INFLUENCE OF SITE PREPARATION ON SOIL MOISTURE AND …
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INFLUENCE OF SITE PREPARATION ON SOIL MOISTURE AND
WEED COMFETITION IN SEMI-ARID TREE PLANTING
BY
ADEL AL-QURASHI
A Thesis submitted to the Graduate School
in partial fulfillment of the requirements
for the Degree
Master of Science
Major Subject Horticulture
New Mexico State University
Las Cruces New Mexico
December 1997
Influence of Site Preparation on Soil Moisture and Weed Competition in Semi-Arid
Tree Planting a thesis prepared by Adel Al-qurashi in partial fulfillment of the
requirements for the degree Master of Science has been approved and accepted by
m rJiLTimomYJ~ Dean of the Graduate School
Chair of the Examining Committee
Date
Committee in charge
Dr John T Harrington Chair
Dr James T Fisher
Dr Leigh Murray
ACKNOWLEDGEMENT
I wish to extend my thanks to my parents my wife and children my family
especially my brother Ibrahim for encouraging and supporting me as I worked
toward completing my graduate degree Also I wish to thank the Government of
Saudi Arabia for providing me with a scholarship and financial support during my
post-graduate education
A special thanks is given to Patrick Glass and Aladdin who were so generous
with their time and knowledge and who helped me tremendously with my research
A special thanks to my friend and advisor Dr John Harrington for all ofhis
support patient and encouragement He is a dedicated researcher and I learned much
from him Also I would like to thank Dr Leigh Murray for her advice and being a
member of my committee
I have a very special thank you for Dr James Fisher who has been a special
person to me during this period of my life He is patient friendly and encouraged me
to excel at my chosen profession
VITA
August 30 1966 - Born at Taif Saudia Arabia
1987 - Graduated from Al-Fasil High School Taif Saudi Arabia
1992 - Bachelor of Science in Arid Land Agriculture King Abdulaziz University
JeddahSaudiArabia
1992 - Teaching Assistant (Demonstrator) at Arid Land Agriculture Department
Jeddah Saudi Arabia
1995-1997 - Graduate Student New Mexico State University
PROFESSIONAL AND HONORAQRY SOCIETIES
Gamma Sigma Delta - National Agriculture Honorary
FIELD OF STUDY
Major Field Horticulture
ABSTRACT
INFLUENCE OF SITE PREPARATION ON SOIL MOISTURE AND
WEED COMPETITION IN SEMI-ARID PLANTING
BY
ADEL DUIF ALLAH AL-QURASHI
Master of Science in Horticulture
New Mexico State University
Las Cruces New Mexico 1997
John T Harrington Chair
A site preparation technique utilizing a synthetic weed barrier and rainfall
harvesting has shown promise in establishing trees in semi-arid area with only one
irrigation at time of planting The objectives of this experiment were to detennine the
effect of two site preparation techniques v-ditch (rainfall harvesting) and synthetic
weed barrier alone and in combination on soil moisture and temperature in the root
zone of target trees A secondary objective was to evaluate the efficacy of these site
preparation treatments on weed control two years after treatment imposition
The planting was located at the New Mexico State University Los Lunas
Agriculture Science Center The planting site was irrigated once with 15 cm ofwater
from a flood irrigation system Seedling survival and height were measured for
Arizona cypress (Cupressus arizonica) Soil moisture content was measured for each
site preparation treatment at nine loci beneath the treatments for seven weeks
following irrigation Soil and air temperature were also measured throughout the
duration (34 days) of this study Competing vegetation w~ measured at the end of
the soil moisture sampling period by using the line intercept method
The low power of the experimental design and high variability within treatments
resulted in the failure to find significant (alpha = 005) differences in seedling
survival and soil moisture even though over twomiddotfold differences existed Two-year
height improved as site preparation intensity increased Site preparation treatments
did not alter crown or soil temperature Even though no significant differences were
detected the observed improved survival growth and soil moisture retention indicate
the combination ofrainfall harvesting and weed barrier is sufficient to established
windbreak in the Middle Rio Grande Valley
TABLE OF CONTENTS
LIST OF TABLES ~ ix
LIST OF FIGURES x
INTRODUCTION 1
LITERATURE REVIEW 4
Tree Establishment in Semi-Arid Lands 4
Site Preparation 5
Rainfall Harvesting 6
Mulches 7
Agriculture in the Middle Rio Grande Region 10
Arizona Cypress 12
MATERIAL AND METHODS 13
Study Site 13
Site Preparation Treatments 13
Plant Measurements 14
Soil Moisture Measurements 14
Soil and Air Temperature Measurement 16
Competing Vegetation Measurements 16
RESULTS 19
Survival and Growth 19
Soil Moisture 19
Crown and Soil Temperatures 34
Weed Competition 37
DISCUSSION 56
CONCLUSION 61
LITERATURE CITED 62
APPENDIX Pressure Potential Equation 68
LIST OF TABLES
Table 1 Temperature probe locations used in the study 18
Table 2 Analysis ofvariance table for two-year survival percent ofArizona Cypress seedling under four site preparation treatments in Los Lunas NM 20
Table 3 Analysis ofvariance table for two-year height of Arizona Cypress seedling under four site preparation treatments in Los Lunas NM 22
Table 4 Analysis ofvariance table for weed coverage along the edge ofsite preparation treatments in Los Lunas NM 49
Table 5 Analysis ofvariance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM 50
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation treatments in Los Lunas NM 51
Table 7 Mean value for weed coverage along the center of site preparation Treatments in Los Lunas NM52
LIST OF FIGURES
Figure 1 The effect of site preparation on 2 years survival ofArizona cypress 21
Figure 2 The effect of site preparation on 2 years height ofArizona cypress 23
Figure 3 Change in soil moisture potential at loci 1 from 0 to 34 days after last irrigation for the four site preparation treatments 24
Figure 4 Change in soil moisture potential at loci 2 from 0 to 34 days after last irrigation for the four site preparation treatments 25
Figure 5 Change in soil moisture potential at loci 3 from 0 to 34 days after last irrigation for the four site preparation treatments 26
Figure 6 Change in soil moisture potential at loci 4 from 0 to 34 days after last irrigation for the four site preparation treatments 27middot
Figure 7 Change in soil moisture potential at loci 5 from 0 to 34 days after last irrigation for the four site preparation treatments 28
Figure 8 Change in soil moisture potential at loci 6 from 0 to 34 days after last irrigation for the four site preparation treatments 29
Figure 9 Change in soil moisture potential at loci 7 from 0 to 34 days after last irrigation for the four site preparation treatments 30
Figure 10 Change in soil moisture potential at loci 8 from 0 to 34 days after last irrigation for the four site preparation treatments 31
Figure 11 Change in soil moisture potential at loci 9 from 0 to 34 days after last irrigation for the four site preparation treatments 32
Figure 12 Graphic (fill) ofdry-down patterns for all giving loci over the duration of the study 33
Figure 13 Daily high and low temperature in the ambient air and in the crown of Arizona cypress seedling growing in control plots 35
Figure 14 Daily high and low temperature in the ambient air and in the crown ofArizona cypress seedling growing in V -ditch and weed barrier plots middot 36
x
Figure 15 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in control plots 39
Figure 16 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 40
Figure 17 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 41
Figure 18 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 42
Figure 19 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in control plots 43
Figure 20 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 44
Figure 21 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 45
Figure 22 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 46
Figure 23 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in control plots 47
Figure 24 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 48
Figure 25 Percent coverage for Salsoa Sporobolus aeroides and other plant coverage along the edge of site preparation treatments averaged across all three blocks 53
Figure 26 Percent coverage for Salsoa kali Sporobolus aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks 54
Figure 27 Percent coverage for Salsoa kaU Sporobolus aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks 55
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INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
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barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
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and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
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land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
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Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
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Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
Influence of Site Preparation on Soil Moisture and Weed Competition in Semi-Arid
Tree Planting a thesis prepared by Adel Al-qurashi in partial fulfillment of the
requirements for the degree Master of Science has been approved and accepted by
m rJiLTimomYJ~ Dean of the Graduate School
Chair of the Examining Committee
Date
Committee in charge
Dr John T Harrington Chair
Dr James T Fisher
Dr Leigh Murray
ACKNOWLEDGEMENT
I wish to extend my thanks to my parents my wife and children my family
especially my brother Ibrahim for encouraging and supporting me as I worked
toward completing my graduate degree Also I wish to thank the Government of
Saudi Arabia for providing me with a scholarship and financial support during my
post-graduate education
A special thanks is given to Patrick Glass and Aladdin who were so generous
with their time and knowledge and who helped me tremendously with my research
A special thanks to my friend and advisor Dr John Harrington for all ofhis
support patient and encouragement He is a dedicated researcher and I learned much
from him Also I would like to thank Dr Leigh Murray for her advice and being a
member of my committee
I have a very special thank you for Dr James Fisher who has been a special
person to me during this period of my life He is patient friendly and encouraged me
to excel at my chosen profession
VITA
August 30 1966 - Born at Taif Saudia Arabia
1987 - Graduated from Al-Fasil High School Taif Saudi Arabia
1992 - Bachelor of Science in Arid Land Agriculture King Abdulaziz University
JeddahSaudiArabia
1992 - Teaching Assistant (Demonstrator) at Arid Land Agriculture Department
Jeddah Saudi Arabia
1995-1997 - Graduate Student New Mexico State University
PROFESSIONAL AND HONORAQRY SOCIETIES
Gamma Sigma Delta - National Agriculture Honorary
FIELD OF STUDY
Major Field Horticulture
ABSTRACT
INFLUENCE OF SITE PREPARATION ON SOIL MOISTURE AND
WEED COMPETITION IN SEMI-ARID PLANTING
BY
ADEL DUIF ALLAH AL-QURASHI
Master of Science in Horticulture
New Mexico State University
Las Cruces New Mexico 1997
John T Harrington Chair
A site preparation technique utilizing a synthetic weed barrier and rainfall
harvesting has shown promise in establishing trees in semi-arid area with only one
irrigation at time of planting The objectives of this experiment were to detennine the
effect of two site preparation techniques v-ditch (rainfall harvesting) and synthetic
weed barrier alone and in combination on soil moisture and temperature in the root
zone of target trees A secondary objective was to evaluate the efficacy of these site
preparation treatments on weed control two years after treatment imposition
The planting was located at the New Mexico State University Los Lunas
Agriculture Science Center The planting site was irrigated once with 15 cm ofwater
from a flood irrigation system Seedling survival and height were measured for
Arizona cypress (Cupressus arizonica) Soil moisture content was measured for each
site preparation treatment at nine loci beneath the treatments for seven weeks
following irrigation Soil and air temperature were also measured throughout the
duration (34 days) of this study Competing vegetation w~ measured at the end of
the soil moisture sampling period by using the line intercept method
The low power of the experimental design and high variability within treatments
resulted in the failure to find significant (alpha = 005) differences in seedling
survival and soil moisture even though over twomiddotfold differences existed Two-year
height improved as site preparation intensity increased Site preparation treatments
did not alter crown or soil temperature Even though no significant differences were
detected the observed improved survival growth and soil moisture retention indicate
the combination ofrainfall harvesting and weed barrier is sufficient to established
windbreak in the Middle Rio Grande Valley
TABLE OF CONTENTS
LIST OF TABLES ~ ix
LIST OF FIGURES x
INTRODUCTION 1
LITERATURE REVIEW 4
Tree Establishment in Semi-Arid Lands 4
Site Preparation 5
Rainfall Harvesting 6
Mulches 7
Agriculture in the Middle Rio Grande Region 10
Arizona Cypress 12
MATERIAL AND METHODS 13
Study Site 13
Site Preparation Treatments 13
Plant Measurements 14
Soil Moisture Measurements 14
Soil and Air Temperature Measurement 16
Competing Vegetation Measurements 16
RESULTS 19
Survival and Growth 19
Soil Moisture 19
Crown and Soil Temperatures 34
Weed Competition 37
DISCUSSION 56
CONCLUSION 61
LITERATURE CITED 62
APPENDIX Pressure Potential Equation 68
LIST OF TABLES
Table 1 Temperature probe locations used in the study 18
Table 2 Analysis ofvariance table for two-year survival percent ofArizona Cypress seedling under four site preparation treatments in Los Lunas NM 20
Table 3 Analysis ofvariance table for two-year height of Arizona Cypress seedling under four site preparation treatments in Los Lunas NM 22
Table 4 Analysis ofvariance table for weed coverage along the edge ofsite preparation treatments in Los Lunas NM 49
Table 5 Analysis ofvariance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM 50
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation treatments in Los Lunas NM 51
Table 7 Mean value for weed coverage along the center of site preparation Treatments in Los Lunas NM52
LIST OF FIGURES
Figure 1 The effect of site preparation on 2 years survival ofArizona cypress 21
Figure 2 The effect of site preparation on 2 years height ofArizona cypress 23
Figure 3 Change in soil moisture potential at loci 1 from 0 to 34 days after last irrigation for the four site preparation treatments 24
Figure 4 Change in soil moisture potential at loci 2 from 0 to 34 days after last irrigation for the four site preparation treatments 25
Figure 5 Change in soil moisture potential at loci 3 from 0 to 34 days after last irrigation for the four site preparation treatments 26
Figure 6 Change in soil moisture potential at loci 4 from 0 to 34 days after last irrigation for the four site preparation treatments 27middot
Figure 7 Change in soil moisture potential at loci 5 from 0 to 34 days after last irrigation for the four site preparation treatments 28
Figure 8 Change in soil moisture potential at loci 6 from 0 to 34 days after last irrigation for the four site preparation treatments 29
Figure 9 Change in soil moisture potential at loci 7 from 0 to 34 days after last irrigation for the four site preparation treatments 30
Figure 10 Change in soil moisture potential at loci 8 from 0 to 34 days after last irrigation for the four site preparation treatments 31
Figure 11 Change in soil moisture potential at loci 9 from 0 to 34 days after last irrigation for the four site preparation treatments 32
Figure 12 Graphic (fill) ofdry-down patterns for all giving loci over the duration of the study 33
Figure 13 Daily high and low temperature in the ambient air and in the crown of Arizona cypress seedling growing in control plots 35
Figure 14 Daily high and low temperature in the ambient air and in the crown ofArizona cypress seedling growing in V -ditch and weed barrier plots middot 36
x
Figure 15 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in control plots 39
Figure 16 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 40
Figure 17 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 41
Figure 18 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 42
Figure 19 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in control plots 43
Figure 20 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 44
Figure 21 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 45
Figure 22 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 46
Figure 23 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in control plots 47
Figure 24 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 48
Figure 25 Percent coverage for Salsoa Sporobolus aeroides and other plant coverage along the edge of site preparation treatments averaged across all three blocks 53
Figure 26 Percent coverage for Salsoa kali Sporobolus aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks 54
Figure 27 Percent coverage for Salsoa kaU Sporobolus aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks 55
xi
INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
ACKNOWLEDGEMENT
I wish to extend my thanks to my parents my wife and children my family
especially my brother Ibrahim for encouraging and supporting me as I worked
toward completing my graduate degree Also I wish to thank the Government of
Saudi Arabia for providing me with a scholarship and financial support during my
post-graduate education
A special thanks is given to Patrick Glass and Aladdin who were so generous
with their time and knowledge and who helped me tremendously with my research
A special thanks to my friend and advisor Dr John Harrington for all ofhis
support patient and encouragement He is a dedicated researcher and I learned much
from him Also I would like to thank Dr Leigh Murray for her advice and being a
member of my committee
I have a very special thank you for Dr James Fisher who has been a special
person to me during this period of my life He is patient friendly and encouraged me
to excel at my chosen profession
VITA
August 30 1966 - Born at Taif Saudia Arabia
1987 - Graduated from Al-Fasil High School Taif Saudi Arabia
1992 - Bachelor of Science in Arid Land Agriculture King Abdulaziz University
JeddahSaudiArabia
1992 - Teaching Assistant (Demonstrator) at Arid Land Agriculture Department
Jeddah Saudi Arabia
1995-1997 - Graduate Student New Mexico State University
PROFESSIONAL AND HONORAQRY SOCIETIES
Gamma Sigma Delta - National Agriculture Honorary
FIELD OF STUDY
Major Field Horticulture
ABSTRACT
INFLUENCE OF SITE PREPARATION ON SOIL MOISTURE AND
WEED COMPETITION IN SEMI-ARID PLANTING
BY
ADEL DUIF ALLAH AL-QURASHI
Master of Science in Horticulture
New Mexico State University
Las Cruces New Mexico 1997
John T Harrington Chair
A site preparation technique utilizing a synthetic weed barrier and rainfall
harvesting has shown promise in establishing trees in semi-arid area with only one
irrigation at time of planting The objectives of this experiment were to detennine the
effect of two site preparation techniques v-ditch (rainfall harvesting) and synthetic
weed barrier alone and in combination on soil moisture and temperature in the root
zone of target trees A secondary objective was to evaluate the efficacy of these site
preparation treatments on weed control two years after treatment imposition
The planting was located at the New Mexico State University Los Lunas
Agriculture Science Center The planting site was irrigated once with 15 cm ofwater
from a flood irrigation system Seedling survival and height were measured for
Arizona cypress (Cupressus arizonica) Soil moisture content was measured for each
site preparation treatment at nine loci beneath the treatments for seven weeks
following irrigation Soil and air temperature were also measured throughout the
duration (34 days) of this study Competing vegetation w~ measured at the end of
the soil moisture sampling period by using the line intercept method
The low power of the experimental design and high variability within treatments
resulted in the failure to find significant (alpha = 005) differences in seedling
survival and soil moisture even though over twomiddotfold differences existed Two-year
height improved as site preparation intensity increased Site preparation treatments
did not alter crown or soil temperature Even though no significant differences were
detected the observed improved survival growth and soil moisture retention indicate
the combination ofrainfall harvesting and weed barrier is sufficient to established
windbreak in the Middle Rio Grande Valley
TABLE OF CONTENTS
LIST OF TABLES ~ ix
LIST OF FIGURES x
INTRODUCTION 1
LITERATURE REVIEW 4
Tree Establishment in Semi-Arid Lands 4
Site Preparation 5
Rainfall Harvesting 6
Mulches 7
Agriculture in the Middle Rio Grande Region 10
Arizona Cypress 12
MATERIAL AND METHODS 13
Study Site 13
Site Preparation Treatments 13
Plant Measurements 14
Soil Moisture Measurements 14
Soil and Air Temperature Measurement 16
Competing Vegetation Measurements 16
RESULTS 19
Survival and Growth 19
Soil Moisture 19
Crown and Soil Temperatures 34
Weed Competition 37
DISCUSSION 56
CONCLUSION 61
LITERATURE CITED 62
APPENDIX Pressure Potential Equation 68
LIST OF TABLES
Table 1 Temperature probe locations used in the study 18
Table 2 Analysis ofvariance table for two-year survival percent ofArizona Cypress seedling under four site preparation treatments in Los Lunas NM 20
Table 3 Analysis ofvariance table for two-year height of Arizona Cypress seedling under four site preparation treatments in Los Lunas NM 22
Table 4 Analysis ofvariance table for weed coverage along the edge ofsite preparation treatments in Los Lunas NM 49
Table 5 Analysis ofvariance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM 50
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation treatments in Los Lunas NM 51
Table 7 Mean value for weed coverage along the center of site preparation Treatments in Los Lunas NM52
LIST OF FIGURES
Figure 1 The effect of site preparation on 2 years survival ofArizona cypress 21
Figure 2 The effect of site preparation on 2 years height ofArizona cypress 23
Figure 3 Change in soil moisture potential at loci 1 from 0 to 34 days after last irrigation for the four site preparation treatments 24
Figure 4 Change in soil moisture potential at loci 2 from 0 to 34 days after last irrigation for the four site preparation treatments 25
Figure 5 Change in soil moisture potential at loci 3 from 0 to 34 days after last irrigation for the four site preparation treatments 26
Figure 6 Change in soil moisture potential at loci 4 from 0 to 34 days after last irrigation for the four site preparation treatments 27middot
Figure 7 Change in soil moisture potential at loci 5 from 0 to 34 days after last irrigation for the four site preparation treatments 28
Figure 8 Change in soil moisture potential at loci 6 from 0 to 34 days after last irrigation for the four site preparation treatments 29
Figure 9 Change in soil moisture potential at loci 7 from 0 to 34 days after last irrigation for the four site preparation treatments 30
Figure 10 Change in soil moisture potential at loci 8 from 0 to 34 days after last irrigation for the four site preparation treatments 31
Figure 11 Change in soil moisture potential at loci 9 from 0 to 34 days after last irrigation for the four site preparation treatments 32
Figure 12 Graphic (fill) ofdry-down patterns for all giving loci over the duration of the study 33
Figure 13 Daily high and low temperature in the ambient air and in the crown of Arizona cypress seedling growing in control plots 35
Figure 14 Daily high and low temperature in the ambient air and in the crown ofArizona cypress seedling growing in V -ditch and weed barrier plots middot 36
x
Figure 15 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in control plots 39
Figure 16 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 40
Figure 17 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 41
Figure 18 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 42
Figure 19 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in control plots 43
Figure 20 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 44
Figure 21 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 45
Figure 22 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 46
Figure 23 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in control plots 47
Figure 24 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 48
Figure 25 Percent coverage for Salsoa Sporobolus aeroides and other plant coverage along the edge of site preparation treatments averaged across all three blocks 53
Figure 26 Percent coverage for Salsoa kali Sporobolus aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks 54
Figure 27 Percent coverage for Salsoa kaU Sporobolus aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks 55
xi
INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
VITA
August 30 1966 - Born at Taif Saudia Arabia
1987 - Graduated from Al-Fasil High School Taif Saudi Arabia
1992 - Bachelor of Science in Arid Land Agriculture King Abdulaziz University
JeddahSaudiArabia
1992 - Teaching Assistant (Demonstrator) at Arid Land Agriculture Department
Jeddah Saudi Arabia
1995-1997 - Graduate Student New Mexico State University
PROFESSIONAL AND HONORAQRY SOCIETIES
Gamma Sigma Delta - National Agriculture Honorary
FIELD OF STUDY
Major Field Horticulture
ABSTRACT
INFLUENCE OF SITE PREPARATION ON SOIL MOISTURE AND
WEED COMPETITION IN SEMI-ARID PLANTING
BY
ADEL DUIF ALLAH AL-QURASHI
Master of Science in Horticulture
New Mexico State University
Las Cruces New Mexico 1997
John T Harrington Chair
A site preparation technique utilizing a synthetic weed barrier and rainfall
harvesting has shown promise in establishing trees in semi-arid area with only one
irrigation at time of planting The objectives of this experiment were to detennine the
effect of two site preparation techniques v-ditch (rainfall harvesting) and synthetic
weed barrier alone and in combination on soil moisture and temperature in the root
zone of target trees A secondary objective was to evaluate the efficacy of these site
preparation treatments on weed control two years after treatment imposition
The planting was located at the New Mexico State University Los Lunas
Agriculture Science Center The planting site was irrigated once with 15 cm ofwater
from a flood irrigation system Seedling survival and height were measured for
Arizona cypress (Cupressus arizonica) Soil moisture content was measured for each
site preparation treatment at nine loci beneath the treatments for seven weeks
following irrigation Soil and air temperature were also measured throughout the
duration (34 days) of this study Competing vegetation w~ measured at the end of
the soil moisture sampling period by using the line intercept method
The low power of the experimental design and high variability within treatments
resulted in the failure to find significant (alpha = 005) differences in seedling
survival and soil moisture even though over twomiddotfold differences existed Two-year
height improved as site preparation intensity increased Site preparation treatments
did not alter crown or soil temperature Even though no significant differences were
detected the observed improved survival growth and soil moisture retention indicate
the combination ofrainfall harvesting and weed barrier is sufficient to established
windbreak in the Middle Rio Grande Valley
TABLE OF CONTENTS
LIST OF TABLES ~ ix
LIST OF FIGURES x
INTRODUCTION 1
LITERATURE REVIEW 4
Tree Establishment in Semi-Arid Lands 4
Site Preparation 5
Rainfall Harvesting 6
Mulches 7
Agriculture in the Middle Rio Grande Region 10
Arizona Cypress 12
MATERIAL AND METHODS 13
Study Site 13
Site Preparation Treatments 13
Plant Measurements 14
Soil Moisture Measurements 14
Soil and Air Temperature Measurement 16
Competing Vegetation Measurements 16
RESULTS 19
Survival and Growth 19
Soil Moisture 19
Crown and Soil Temperatures 34
Weed Competition 37
DISCUSSION 56
CONCLUSION 61
LITERATURE CITED 62
APPENDIX Pressure Potential Equation 68
LIST OF TABLES
Table 1 Temperature probe locations used in the study 18
Table 2 Analysis ofvariance table for two-year survival percent ofArizona Cypress seedling under four site preparation treatments in Los Lunas NM 20
Table 3 Analysis ofvariance table for two-year height of Arizona Cypress seedling under four site preparation treatments in Los Lunas NM 22
Table 4 Analysis ofvariance table for weed coverage along the edge ofsite preparation treatments in Los Lunas NM 49
Table 5 Analysis ofvariance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM 50
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation treatments in Los Lunas NM 51
Table 7 Mean value for weed coverage along the center of site preparation Treatments in Los Lunas NM52
LIST OF FIGURES
Figure 1 The effect of site preparation on 2 years survival ofArizona cypress 21
Figure 2 The effect of site preparation on 2 years height ofArizona cypress 23
Figure 3 Change in soil moisture potential at loci 1 from 0 to 34 days after last irrigation for the four site preparation treatments 24
Figure 4 Change in soil moisture potential at loci 2 from 0 to 34 days after last irrigation for the four site preparation treatments 25
Figure 5 Change in soil moisture potential at loci 3 from 0 to 34 days after last irrigation for the four site preparation treatments 26
Figure 6 Change in soil moisture potential at loci 4 from 0 to 34 days after last irrigation for the four site preparation treatments 27middot
Figure 7 Change in soil moisture potential at loci 5 from 0 to 34 days after last irrigation for the four site preparation treatments 28
Figure 8 Change in soil moisture potential at loci 6 from 0 to 34 days after last irrigation for the four site preparation treatments 29
Figure 9 Change in soil moisture potential at loci 7 from 0 to 34 days after last irrigation for the four site preparation treatments 30
Figure 10 Change in soil moisture potential at loci 8 from 0 to 34 days after last irrigation for the four site preparation treatments 31
Figure 11 Change in soil moisture potential at loci 9 from 0 to 34 days after last irrigation for the four site preparation treatments 32
Figure 12 Graphic (fill) ofdry-down patterns for all giving loci over the duration of the study 33
Figure 13 Daily high and low temperature in the ambient air and in the crown of Arizona cypress seedling growing in control plots 35
Figure 14 Daily high and low temperature in the ambient air and in the crown ofArizona cypress seedling growing in V -ditch and weed barrier plots middot 36
x
Figure 15 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in control plots 39
Figure 16 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 40
Figure 17 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 41
Figure 18 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 42
Figure 19 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in control plots 43
Figure 20 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 44
Figure 21 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 45
Figure 22 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 46
Figure 23 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in control plots 47
Figure 24 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 48
Figure 25 Percent coverage for Salsoa Sporobolus aeroides and other plant coverage along the edge of site preparation treatments averaged across all three blocks 53
Figure 26 Percent coverage for Salsoa kali Sporobolus aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks 54
Figure 27 Percent coverage for Salsoa kaU Sporobolus aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks 55
xi
INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
ABSTRACT
INFLUENCE OF SITE PREPARATION ON SOIL MOISTURE AND
WEED COMPETITION IN SEMI-ARID PLANTING
BY
ADEL DUIF ALLAH AL-QURASHI
Master of Science in Horticulture
New Mexico State University
Las Cruces New Mexico 1997
John T Harrington Chair
A site preparation technique utilizing a synthetic weed barrier and rainfall
harvesting has shown promise in establishing trees in semi-arid area with only one
irrigation at time of planting The objectives of this experiment were to detennine the
effect of two site preparation techniques v-ditch (rainfall harvesting) and synthetic
weed barrier alone and in combination on soil moisture and temperature in the root
zone of target trees A secondary objective was to evaluate the efficacy of these site
preparation treatments on weed control two years after treatment imposition
The planting was located at the New Mexico State University Los Lunas
Agriculture Science Center The planting site was irrigated once with 15 cm ofwater
from a flood irrigation system Seedling survival and height were measured for
Arizona cypress (Cupressus arizonica) Soil moisture content was measured for each
site preparation treatment at nine loci beneath the treatments for seven weeks
following irrigation Soil and air temperature were also measured throughout the
duration (34 days) of this study Competing vegetation w~ measured at the end of
the soil moisture sampling period by using the line intercept method
The low power of the experimental design and high variability within treatments
resulted in the failure to find significant (alpha = 005) differences in seedling
survival and soil moisture even though over twomiddotfold differences existed Two-year
height improved as site preparation intensity increased Site preparation treatments
did not alter crown or soil temperature Even though no significant differences were
detected the observed improved survival growth and soil moisture retention indicate
the combination ofrainfall harvesting and weed barrier is sufficient to established
windbreak in the Middle Rio Grande Valley
TABLE OF CONTENTS
LIST OF TABLES ~ ix
LIST OF FIGURES x
INTRODUCTION 1
LITERATURE REVIEW 4
Tree Establishment in Semi-Arid Lands 4
Site Preparation 5
Rainfall Harvesting 6
Mulches 7
Agriculture in the Middle Rio Grande Region 10
Arizona Cypress 12
MATERIAL AND METHODS 13
Study Site 13
Site Preparation Treatments 13
Plant Measurements 14
Soil Moisture Measurements 14
Soil and Air Temperature Measurement 16
Competing Vegetation Measurements 16
RESULTS 19
Survival and Growth 19
Soil Moisture 19
Crown and Soil Temperatures 34
Weed Competition 37
DISCUSSION 56
CONCLUSION 61
LITERATURE CITED 62
APPENDIX Pressure Potential Equation 68
LIST OF TABLES
Table 1 Temperature probe locations used in the study 18
Table 2 Analysis ofvariance table for two-year survival percent ofArizona Cypress seedling under four site preparation treatments in Los Lunas NM 20
Table 3 Analysis ofvariance table for two-year height of Arizona Cypress seedling under four site preparation treatments in Los Lunas NM 22
Table 4 Analysis ofvariance table for weed coverage along the edge ofsite preparation treatments in Los Lunas NM 49
Table 5 Analysis ofvariance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM 50
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation treatments in Los Lunas NM 51
Table 7 Mean value for weed coverage along the center of site preparation Treatments in Los Lunas NM52
LIST OF FIGURES
Figure 1 The effect of site preparation on 2 years survival ofArizona cypress 21
Figure 2 The effect of site preparation on 2 years height ofArizona cypress 23
Figure 3 Change in soil moisture potential at loci 1 from 0 to 34 days after last irrigation for the four site preparation treatments 24
Figure 4 Change in soil moisture potential at loci 2 from 0 to 34 days after last irrigation for the four site preparation treatments 25
Figure 5 Change in soil moisture potential at loci 3 from 0 to 34 days after last irrigation for the four site preparation treatments 26
Figure 6 Change in soil moisture potential at loci 4 from 0 to 34 days after last irrigation for the four site preparation treatments 27middot
Figure 7 Change in soil moisture potential at loci 5 from 0 to 34 days after last irrigation for the four site preparation treatments 28
Figure 8 Change in soil moisture potential at loci 6 from 0 to 34 days after last irrigation for the four site preparation treatments 29
Figure 9 Change in soil moisture potential at loci 7 from 0 to 34 days after last irrigation for the four site preparation treatments 30
Figure 10 Change in soil moisture potential at loci 8 from 0 to 34 days after last irrigation for the four site preparation treatments 31
Figure 11 Change in soil moisture potential at loci 9 from 0 to 34 days after last irrigation for the four site preparation treatments 32
Figure 12 Graphic (fill) ofdry-down patterns for all giving loci over the duration of the study 33
Figure 13 Daily high and low temperature in the ambient air and in the crown of Arizona cypress seedling growing in control plots 35
Figure 14 Daily high and low temperature in the ambient air and in the crown ofArizona cypress seedling growing in V -ditch and weed barrier plots middot 36
x
Figure 15 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in control plots 39
Figure 16 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 40
Figure 17 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 41
Figure 18 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 42
Figure 19 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in control plots 43
Figure 20 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 44
Figure 21 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 45
Figure 22 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 46
Figure 23 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in control plots 47
Figure 24 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 48
Figure 25 Percent coverage for Salsoa Sporobolus aeroides and other plant coverage along the edge of site preparation treatments averaged across all three blocks 53
Figure 26 Percent coverage for Salsoa kali Sporobolus aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks 54
Figure 27 Percent coverage for Salsoa kaU Sporobolus aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks 55
xi
INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
following irrigation Soil and air temperature were also measured throughout the
duration (34 days) of this study Competing vegetation w~ measured at the end of
the soil moisture sampling period by using the line intercept method
The low power of the experimental design and high variability within treatments
resulted in the failure to find significant (alpha = 005) differences in seedling
survival and soil moisture even though over twomiddotfold differences existed Two-year
height improved as site preparation intensity increased Site preparation treatments
did not alter crown or soil temperature Even though no significant differences were
detected the observed improved survival growth and soil moisture retention indicate
the combination ofrainfall harvesting and weed barrier is sufficient to established
windbreak in the Middle Rio Grande Valley
TABLE OF CONTENTS
LIST OF TABLES ~ ix
LIST OF FIGURES x
INTRODUCTION 1
LITERATURE REVIEW 4
Tree Establishment in Semi-Arid Lands 4
Site Preparation 5
Rainfall Harvesting 6
Mulches 7
Agriculture in the Middle Rio Grande Region 10
Arizona Cypress 12
MATERIAL AND METHODS 13
Study Site 13
Site Preparation Treatments 13
Plant Measurements 14
Soil Moisture Measurements 14
Soil and Air Temperature Measurement 16
Competing Vegetation Measurements 16
RESULTS 19
Survival and Growth 19
Soil Moisture 19
Crown and Soil Temperatures 34
Weed Competition 37
DISCUSSION 56
CONCLUSION 61
LITERATURE CITED 62
APPENDIX Pressure Potential Equation 68
LIST OF TABLES
Table 1 Temperature probe locations used in the study 18
Table 2 Analysis ofvariance table for two-year survival percent ofArizona Cypress seedling under four site preparation treatments in Los Lunas NM 20
Table 3 Analysis ofvariance table for two-year height of Arizona Cypress seedling under four site preparation treatments in Los Lunas NM 22
Table 4 Analysis ofvariance table for weed coverage along the edge ofsite preparation treatments in Los Lunas NM 49
Table 5 Analysis ofvariance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM 50
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation treatments in Los Lunas NM 51
Table 7 Mean value for weed coverage along the center of site preparation Treatments in Los Lunas NM52
LIST OF FIGURES
Figure 1 The effect of site preparation on 2 years survival ofArizona cypress 21
Figure 2 The effect of site preparation on 2 years height ofArizona cypress 23
Figure 3 Change in soil moisture potential at loci 1 from 0 to 34 days after last irrigation for the four site preparation treatments 24
Figure 4 Change in soil moisture potential at loci 2 from 0 to 34 days after last irrigation for the four site preparation treatments 25
Figure 5 Change in soil moisture potential at loci 3 from 0 to 34 days after last irrigation for the four site preparation treatments 26
Figure 6 Change in soil moisture potential at loci 4 from 0 to 34 days after last irrigation for the four site preparation treatments 27middot
Figure 7 Change in soil moisture potential at loci 5 from 0 to 34 days after last irrigation for the four site preparation treatments 28
Figure 8 Change in soil moisture potential at loci 6 from 0 to 34 days after last irrigation for the four site preparation treatments 29
Figure 9 Change in soil moisture potential at loci 7 from 0 to 34 days after last irrigation for the four site preparation treatments 30
Figure 10 Change in soil moisture potential at loci 8 from 0 to 34 days after last irrigation for the four site preparation treatments 31
Figure 11 Change in soil moisture potential at loci 9 from 0 to 34 days after last irrigation for the four site preparation treatments 32
Figure 12 Graphic (fill) ofdry-down patterns for all giving loci over the duration of the study 33
Figure 13 Daily high and low temperature in the ambient air and in the crown of Arizona cypress seedling growing in control plots 35
Figure 14 Daily high and low temperature in the ambient air and in the crown ofArizona cypress seedling growing in V -ditch and weed barrier plots middot 36
x
Figure 15 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in control plots 39
Figure 16 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 40
Figure 17 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 41
Figure 18 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 42
Figure 19 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in control plots 43
Figure 20 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 44
Figure 21 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 45
Figure 22 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 46
Figure 23 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in control plots 47
Figure 24 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 48
Figure 25 Percent coverage for Salsoa Sporobolus aeroides and other plant coverage along the edge of site preparation treatments averaged across all three blocks 53
Figure 26 Percent coverage for Salsoa kali Sporobolus aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks 54
Figure 27 Percent coverage for Salsoa kaU Sporobolus aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks 55
xi
INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
TABLE OF CONTENTS
LIST OF TABLES ~ ix
LIST OF FIGURES x
INTRODUCTION 1
LITERATURE REVIEW 4
Tree Establishment in Semi-Arid Lands 4
Site Preparation 5
Rainfall Harvesting 6
Mulches 7
Agriculture in the Middle Rio Grande Region 10
Arizona Cypress 12
MATERIAL AND METHODS 13
Study Site 13
Site Preparation Treatments 13
Plant Measurements 14
Soil Moisture Measurements 14
Soil and Air Temperature Measurement 16
Competing Vegetation Measurements 16
RESULTS 19
Survival and Growth 19
Soil Moisture 19
Crown and Soil Temperatures 34
Weed Competition 37
DISCUSSION 56
CONCLUSION 61
LITERATURE CITED 62
APPENDIX Pressure Potential Equation 68
LIST OF TABLES
Table 1 Temperature probe locations used in the study 18
Table 2 Analysis ofvariance table for two-year survival percent ofArizona Cypress seedling under four site preparation treatments in Los Lunas NM 20
Table 3 Analysis ofvariance table for two-year height of Arizona Cypress seedling under four site preparation treatments in Los Lunas NM 22
Table 4 Analysis ofvariance table for weed coverage along the edge ofsite preparation treatments in Los Lunas NM 49
Table 5 Analysis ofvariance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM 50
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation treatments in Los Lunas NM 51
Table 7 Mean value for weed coverage along the center of site preparation Treatments in Los Lunas NM52
LIST OF FIGURES
Figure 1 The effect of site preparation on 2 years survival ofArizona cypress 21
Figure 2 The effect of site preparation on 2 years height ofArizona cypress 23
Figure 3 Change in soil moisture potential at loci 1 from 0 to 34 days after last irrigation for the four site preparation treatments 24
Figure 4 Change in soil moisture potential at loci 2 from 0 to 34 days after last irrigation for the four site preparation treatments 25
Figure 5 Change in soil moisture potential at loci 3 from 0 to 34 days after last irrigation for the four site preparation treatments 26
Figure 6 Change in soil moisture potential at loci 4 from 0 to 34 days after last irrigation for the four site preparation treatments 27middot
Figure 7 Change in soil moisture potential at loci 5 from 0 to 34 days after last irrigation for the four site preparation treatments 28
Figure 8 Change in soil moisture potential at loci 6 from 0 to 34 days after last irrigation for the four site preparation treatments 29
Figure 9 Change in soil moisture potential at loci 7 from 0 to 34 days after last irrigation for the four site preparation treatments 30
Figure 10 Change in soil moisture potential at loci 8 from 0 to 34 days after last irrigation for the four site preparation treatments 31
Figure 11 Change in soil moisture potential at loci 9 from 0 to 34 days after last irrigation for the four site preparation treatments 32
Figure 12 Graphic (fill) ofdry-down patterns for all giving loci over the duration of the study 33
Figure 13 Daily high and low temperature in the ambient air and in the crown of Arizona cypress seedling growing in control plots 35
Figure 14 Daily high and low temperature in the ambient air and in the crown ofArizona cypress seedling growing in V -ditch and weed barrier plots middot 36
x
Figure 15 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in control plots 39
Figure 16 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 40
Figure 17 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 41
Figure 18 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 42
Figure 19 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in control plots 43
Figure 20 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 44
Figure 21 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 45
Figure 22 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 46
Figure 23 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in control plots 47
Figure 24 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 48
Figure 25 Percent coverage for Salsoa Sporobolus aeroides and other plant coverage along the edge of site preparation treatments averaged across all three blocks 53
Figure 26 Percent coverage for Salsoa kali Sporobolus aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks 54
Figure 27 Percent coverage for Salsoa kaU Sporobolus aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks 55
xi
INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
Crown and Soil Temperatures 34
Weed Competition 37
DISCUSSION 56
CONCLUSION 61
LITERATURE CITED 62
APPENDIX Pressure Potential Equation 68
LIST OF TABLES
Table 1 Temperature probe locations used in the study 18
Table 2 Analysis ofvariance table for two-year survival percent ofArizona Cypress seedling under four site preparation treatments in Los Lunas NM 20
Table 3 Analysis ofvariance table for two-year height of Arizona Cypress seedling under four site preparation treatments in Los Lunas NM 22
Table 4 Analysis ofvariance table for weed coverage along the edge ofsite preparation treatments in Los Lunas NM 49
Table 5 Analysis ofvariance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM 50
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation treatments in Los Lunas NM 51
Table 7 Mean value for weed coverage along the center of site preparation Treatments in Los Lunas NM52
LIST OF FIGURES
Figure 1 The effect of site preparation on 2 years survival ofArizona cypress 21
Figure 2 The effect of site preparation on 2 years height ofArizona cypress 23
Figure 3 Change in soil moisture potential at loci 1 from 0 to 34 days after last irrigation for the four site preparation treatments 24
Figure 4 Change in soil moisture potential at loci 2 from 0 to 34 days after last irrigation for the four site preparation treatments 25
Figure 5 Change in soil moisture potential at loci 3 from 0 to 34 days after last irrigation for the four site preparation treatments 26
Figure 6 Change in soil moisture potential at loci 4 from 0 to 34 days after last irrigation for the four site preparation treatments 27middot
Figure 7 Change in soil moisture potential at loci 5 from 0 to 34 days after last irrigation for the four site preparation treatments 28
Figure 8 Change in soil moisture potential at loci 6 from 0 to 34 days after last irrigation for the four site preparation treatments 29
Figure 9 Change in soil moisture potential at loci 7 from 0 to 34 days after last irrigation for the four site preparation treatments 30
Figure 10 Change in soil moisture potential at loci 8 from 0 to 34 days after last irrigation for the four site preparation treatments 31
Figure 11 Change in soil moisture potential at loci 9 from 0 to 34 days after last irrigation for the four site preparation treatments 32
Figure 12 Graphic (fill) ofdry-down patterns for all giving loci over the duration of the study 33
Figure 13 Daily high and low temperature in the ambient air and in the crown of Arizona cypress seedling growing in control plots 35
Figure 14 Daily high and low temperature in the ambient air and in the crown ofArizona cypress seedling growing in V -ditch and weed barrier plots middot 36
x
Figure 15 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in control plots 39
Figure 16 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 40
Figure 17 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 41
Figure 18 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 42
Figure 19 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in control plots 43
Figure 20 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 44
Figure 21 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 45
Figure 22 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 46
Figure 23 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in control plots 47
Figure 24 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 48
Figure 25 Percent coverage for Salsoa Sporobolus aeroides and other plant coverage along the edge of site preparation treatments averaged across all three blocks 53
Figure 26 Percent coverage for Salsoa kali Sporobolus aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks 54
Figure 27 Percent coverage for Salsoa kaU Sporobolus aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks 55
xi
INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
LIST OF TABLES
Table 1 Temperature probe locations used in the study 18
Table 2 Analysis ofvariance table for two-year survival percent ofArizona Cypress seedling under four site preparation treatments in Los Lunas NM 20
Table 3 Analysis ofvariance table for two-year height of Arizona Cypress seedling under four site preparation treatments in Los Lunas NM 22
Table 4 Analysis ofvariance table for weed coverage along the edge ofsite preparation treatments in Los Lunas NM 49
Table 5 Analysis ofvariance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM 50
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation treatments in Los Lunas NM 51
Table 7 Mean value for weed coverage along the center of site preparation Treatments in Los Lunas NM52
LIST OF FIGURES
Figure 1 The effect of site preparation on 2 years survival ofArizona cypress 21
Figure 2 The effect of site preparation on 2 years height ofArizona cypress 23
Figure 3 Change in soil moisture potential at loci 1 from 0 to 34 days after last irrigation for the four site preparation treatments 24
Figure 4 Change in soil moisture potential at loci 2 from 0 to 34 days after last irrigation for the four site preparation treatments 25
Figure 5 Change in soil moisture potential at loci 3 from 0 to 34 days after last irrigation for the four site preparation treatments 26
Figure 6 Change in soil moisture potential at loci 4 from 0 to 34 days after last irrigation for the four site preparation treatments 27middot
Figure 7 Change in soil moisture potential at loci 5 from 0 to 34 days after last irrigation for the four site preparation treatments 28
Figure 8 Change in soil moisture potential at loci 6 from 0 to 34 days after last irrigation for the four site preparation treatments 29
Figure 9 Change in soil moisture potential at loci 7 from 0 to 34 days after last irrigation for the four site preparation treatments 30
Figure 10 Change in soil moisture potential at loci 8 from 0 to 34 days after last irrigation for the four site preparation treatments 31
Figure 11 Change in soil moisture potential at loci 9 from 0 to 34 days after last irrigation for the four site preparation treatments 32
Figure 12 Graphic (fill) ofdry-down patterns for all giving loci over the duration of the study 33
Figure 13 Daily high and low temperature in the ambient air and in the crown of Arizona cypress seedling growing in control plots 35
Figure 14 Daily high and low temperature in the ambient air and in the crown ofArizona cypress seedling growing in V -ditch and weed barrier plots middot 36
x
Figure 15 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in control plots 39
Figure 16 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 40
Figure 17 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 41
Figure 18 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 42
Figure 19 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in control plots 43
Figure 20 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 44
Figure 21 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 45
Figure 22 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 46
Figure 23 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in control plots 47
Figure 24 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 48
Figure 25 Percent coverage for Salsoa Sporobolus aeroides and other plant coverage along the edge of site preparation treatments averaged across all three blocks 53
Figure 26 Percent coverage for Salsoa kali Sporobolus aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks 54
Figure 27 Percent coverage for Salsoa kaU Sporobolus aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks 55
xi
INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
LIST OF FIGURES
Figure 1 The effect of site preparation on 2 years survival ofArizona cypress 21
Figure 2 The effect of site preparation on 2 years height ofArizona cypress 23
Figure 3 Change in soil moisture potential at loci 1 from 0 to 34 days after last irrigation for the four site preparation treatments 24
Figure 4 Change in soil moisture potential at loci 2 from 0 to 34 days after last irrigation for the four site preparation treatments 25
Figure 5 Change in soil moisture potential at loci 3 from 0 to 34 days after last irrigation for the four site preparation treatments 26
Figure 6 Change in soil moisture potential at loci 4 from 0 to 34 days after last irrigation for the four site preparation treatments 27middot
Figure 7 Change in soil moisture potential at loci 5 from 0 to 34 days after last irrigation for the four site preparation treatments 28
Figure 8 Change in soil moisture potential at loci 6 from 0 to 34 days after last irrigation for the four site preparation treatments 29
Figure 9 Change in soil moisture potential at loci 7 from 0 to 34 days after last irrigation for the four site preparation treatments 30
Figure 10 Change in soil moisture potential at loci 8 from 0 to 34 days after last irrigation for the four site preparation treatments 31
Figure 11 Change in soil moisture potential at loci 9 from 0 to 34 days after last irrigation for the four site preparation treatments 32
Figure 12 Graphic (fill) ofdry-down patterns for all giving loci over the duration of the study 33
Figure 13 Daily high and low temperature in the ambient air and in the crown of Arizona cypress seedling growing in control plots 35
Figure 14 Daily high and low temperature in the ambient air and in the crown ofArizona cypress seedling growing in V -ditch and weed barrier plots middot 36
x
Figure 15 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in control plots 39
Figure 16 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 40
Figure 17 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 41
Figure 18 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 42
Figure 19 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in control plots 43
Figure 20 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 44
Figure 21 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 45
Figure 22 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 46
Figure 23 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in control plots 47
Figure 24 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 48
Figure 25 Percent coverage for Salsoa Sporobolus aeroides and other plant coverage along the edge of site preparation treatments averaged across all three blocks 53
Figure 26 Percent coverage for Salsoa kali Sporobolus aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks 54
Figure 27 Percent coverage for Salsoa kaU Sporobolus aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks 55
xi
INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
Figure 15 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in control plots 39
Figure 16 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 40
Figure 17 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 41
Figure 18 Daily high and low temperature 1 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 42
Figure 19 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in control plots 43
Figure 20 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch plots 44
Figure 21 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in weed barrier plots 45
Figure 22 Daily high and low temperature 23 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 46
Figure 23 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in control plots 47
Figure 24 Daily high and low temperature 38 cm below the soil surface of Arizona cypress seedling growing in V -ditch and weed barrier plots 48
Figure 25 Percent coverage for Salsoa Sporobolus aeroides and other plant coverage along the edge of site preparation treatments averaged across all three blocks 53
Figure 26 Percent coverage for Salsoa kali Sporobolus aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks 54
Figure 27 Percent coverage for Salsoa kaU Sporobolus aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks 55
xi
INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
INTRODUCTION
Arid and semi-arid lands are defined as a place where the amount of available
water for normal crop growth and development is small (White 1960) with an
average annual rainfall ofless than 200 mm and between 200 and 500 mm
respectively (West 1983) Arid and semi-arid lands comprise approximately 35 of
the earths land surface (Walton 1969) and support a population of 850 million people
(Nierenberg 1995) The increase in demand for food and fiber production has
necessitated dependence upon arid and semi-arid land surfaces to satisfy the needs of
the expanding world population
The harsh dry climates in arid and semi-arid areas inhibit plant growth and
development Much ofNew Mexicos agricultural areas are in arid and semi-arid
areas Even under these challenging climatic regimes agriculture contributes
significantly to the economy ofNew Mexico New Mexico has 13500 farms in
operation which cover forty-four million acres not including 222 million acres of
BLM and Forest Service land which is leased to both farmers and ranchers (USDA
1995) In 1996 the total amount ofcash crops grown in the state was estimated to be
$511567000 (USDA 1996)
Further compounding the limitations of semi-arid climate on plant growth in
the United States are the highly erodible soils associated with 30 million hectares of
agricultural regions such as the Great Plains (Skujins 1991) In New Mexico for
example over 340000 hectares of soil eroded in a seven month period from
November 1983 through May 1984 (Huszar and Piper 1986) In some areas ofthe
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
state including Albuquerque and Las Cruces soil loss by wind erosion is estimated to
be 2727 kilograms per hectare per year (Huszar and Piper 1986)
Wind erosion presents challenges to agricultural production in the State of
New Mexico A potential solution to reduce soil erosion is establishment of perennial
plant covers and trees Two approaches exist to incorporate trees into agricultural
enterprises trees as a fruit or nut crop and establishing trees as windbreaks to reduce
wind effects on soil surface Pistachio (Pistacia vera) and pecan (Carya illinoensis)
are nut tree species being used for crop production by New Mexico farmers
Originally from central Asia pistachio trees appeal to growers because they are
adaptable to both climate and soil in the southern area of New Mexico (Crane and
Maranto 1988 Herrera 1997) Pecans have become a major crop in the state and in
1995 orchards produced 2041166 tons of pecans (USDA 1995) Arizona cypress
(Cupressus arizonca) and eldarica pine (Pinus brutia var eldarica) have also been
used in the southern half of the state as windbreaks to reduce soil erosion
Increasing demands on a finite quantity of irrigation water have resulted in
many agriculture enterprises failing to utilize tree crops or windbreaks as a means of
reducing wind erosion A site preparation technique utilizing a synthetic weed barrier
and rainfall harvesting has shown promise in establishing trees in semi-arid areas with
only one irrigation at time of planting (Maiers 1997) The windbreak technique has
been evaluated for evergreen species and also shows promise in applications using
fruit and nut trees The preliminary effects on seedling survival and growth are now
being monitored but little infonnation exists on the effect of using a synthetic weed
2
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
barrier and rainfall harvesting on soil moisture and temperature in the root zone of the
trees
The objectives of this study were to evaluate the effect of two site-preparation
techniques v-ditch (rainfall harvesting) and synthetic weed barrier alone and in
combination on soil moisture and temperature in the root zone oftarget trees A
secondary objective was to evaluate the efficacy ofthese site preparation treatments
on weed control two years after treatment imposition
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
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Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
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Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
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63
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Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
LITERATURE REVIEW
Tree Establishment in Semi-Arid Regions
Precipitation data for Los Lunas NM indicates that the average annual rainfall
measured over a period of 38 years (1957-1994) was 225 cm (Hooks 1996) with
most falling during the growing season April through mid October (Hooks 1996)
However rainfall was variable ranging from 132 cm to 380 cm during this period
(Hooks 1996) It is recommended that transplanting should be done during the
growing season (April through October 15) when 70 of the annual precipitation
falls (Hooks 1996) Monthly precipitation data support transplanting during this
window of time II when rainfall is at maximum for the year Transplanting outside of
this window of time will subject seedling to severe transplant shock in terms of
inadequate soil moisture
Moisture stress is the main cause of transplant shock Transplant shock may
occur ifroot-to-soil contact is not reestablished and the plant is unable to take up
water (Haase and Rose 1993) Symptoms of transplant shock in conifers are bottle
brushing browning loss of needles and cessation of growth (Haase and Rose 1993)
In another study by Hallgren and Helms (1988) symptoms such as reduction of
internode elongation was induced by moisture stress Data supports a 6-12 water
content with normal root volume resulted in a reduction ofnew terminal and lateral
length ofneedles (Haase and Rose 1990) Both these studies support the assumption
that adequate soil moisture content is necessary to deter seedling transplant shock
4
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
Site Preparation
The objective of site preparation is to manipulate the planting site to improve
the survival and growth of tree seedlings by reducing or eliminating site limitations
In most cases site preparation is used to reduce competition for light or improve the
soil-water relation on the site Site preparation can be mechanical or chemical or a
combination of the two Proper site preparation is instrumental for plantation
establishment Planting failure has been attributed to poor site preparation before
planting and site management neglect after (Rasmussen 1990)
The efficacy of site preparation is a function of the site intensity of treatment
and the plant material being established (McClain and Lavender 1989 McMinn 1981
Fisher and Montano 1977) In semi-arid plantings improving soil moisture
availability is the primary objective ofmost site preparation efforts Eliminating or
reducing competing vegetation is often effective in improving soil moisture reserves
(Westwood 1993 lobiden 1990) This can be achieved several ways including the
use ofherbicides or physical barriers such as mulches or through repeated tillage
operations Site preparation technique can also increase the amount ofmoisture
stored in the soil Most often this is achieved through mechanical rainfall harvesting
techniques A third means of improving soil moisture status through site preparation
is by improving water infiltration into the soil This is often achieved mechanically
by repeated surface crust disturbance such as rototilling or disking Patterson et al
(1990) evaluated pecan tree growth using the influence of both chemical and cultural
weed control Four weed control treatments mowing disking grass control only
5
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
and total control were used and Patterson et al (1990) found that disking was as
effective as total control These latter techniques are considered standard operating
protocol prior to irrigation of pecan orchards in Mesilla Valley
Rainfall Harvesting
One site preparation technique used in arid and semi-arid regions and in areas
prone to droughts during the growing season is using rainfall harvesting Rainfall
harvesting involves manipulation of the soil surface around a seedling to concentrate
precipitation towards the rhizophere of the seedling This technique has been shown
to be effective in areas prone to droughts during the growing season Lantagne and
Burger (1987) used a v-blade and disc to build a rainfall harvesting system in the
Southern Piedmont which resulted in improved growth and survival of transplanted
seedlings Stafford et al (1985) used shear v-blade and disc to capture more rainfall
during periods of seedling establishment when rainfall was scarce This technique
proved to be most cost effective especially in retaining nutrients which proved to be
a significant factor in enhancing loblolly pine (Pinus taeda) seedling growth (Stafford
et al 1985) In the Thal Desert ofPakistan (average rainfall 180-200 mm) one meter
slopes inverted on either side of a planting trench (03 m wide x 03 m deep) proved
to be the best system to use under dry regions conditions (Suleman 1992) In
heavier soils a linear v-ditch system improved survival and early growth ofArizona
cypress and eldarica pine in the Pecos Valley of Southeastern New Mexico (Maiers et
al 1997) This technique in conjunction with a synthetic weed barrier is currently
the recommended technique for establishing windbreaks in the Southwestern United
6
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
r
States (Brown et al 1992) The combination of these two treatments has improved
conifer establishment in several New Mexico agricultural regions (Maiers 1997)
Rainfall harvesting is ideally suited to areas with heavier soils prone to large
episodic rain events This type of climate is common in many ofNew Mexicos
agricultural regions The scalping effect of most rainfall harvesting techniques also
eliminates much of the competing vegetation thereby making niore soil moisture
available to the seedling However little information exists on the effect of rainfall
harvesting on soil moisture and temperature in the rooting zone of the seedling
Mulches
Mulching or covering the soil around a tree seedling is also an effective site
preparation technique in arid and semi-arid areas Mulches can be either organic or
inorganic materials such as rocks or synthetic fabrics Organic mulches (rice straw
pecan hulls pine bark etc) have the advantage of improving soil tilth and releasing
nutrients into the soil or they decompose Inorganic mulches have the advantage of
persistence which can be important in maintaining the influence of the mulch for a
greater duration thereby reducing the need for reapplication (Herrera 1996)
An ideal mulch is one which eliminates competing plant growth while still
permitting gas exchange and moisture infiltration Mulches improve soil moisture
status in several ways Mulches can reduce competing vegetation - weeds compete
more aggressively with plants for soil moisture nutrients and light especially during
the establishment phase of the crop (Lee 1994) As a result plant growth and yield
are reduced if weeds are not controlled (Spedding 1981 Tivy 1990) Plastic mulches
7
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
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Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
absorb most photosynthetically active radiation in the 400 to 700 nm range They
also transmit a large portion ofnear-infrared radiation Weeds are controlled under
these mulches due to the photosynthetically active radiation being blocked and near-
infrared radiation transmitted (Maurer and Frey 1991 Loy and Wells 1989) In
micropropagated raspberry (Rubus fruticosus L) plant establishment black
polyethylene mulch had a significant effect in complete weed control during the
establishment phase straw mulch did not suppress most annual and perennial weed
species during this study (Trinka and Pritts 1992)
Mulches also improve soil moisture retention by reducing evaporation of
moisture from the soil surface to the atmosphere (Fereres and Goldhamer 1991)
Black and Greb (1961) stated that plastic mulch frequently increased plant growth in
nonirrigated regions They reduced evaporation of soil moisture as well as increased
water-use efficiency by the plant as compared with bare soil (Black and Greb 1961
Borland and Weinstein 1989) Maintaining adequate soil moisture and fertility during
the growing season is necessary for successful seedling establishment rvan Sambeek
et al 1995) Lack of weed control decreased soil moisture potential more rapidly in
plots covered with dense vegetation The use of plastic film allowed soil moisture
potential to decline more slowly than in the other treatments rvan Sambeek et al
1995) In a study by Mbagwu (1991) it was reported that on bare plots soil moisture
reserve depleted by 642 on straw plots 577 on black plastic mulch plots
369 and on white plastic mulch plots 20
8
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
Mulches can also improve soil moisture by preventing crusting and improving
infiltration into the soil With the absence ofcultivation and a low amount of
compaction even thin mulches allow the structure of the soil to improve and increase
the infiltration rate This will allow a more uniform distribution ofwater and less soil
erosion (Harris 1992) Tindall et al (1991) found that water infiltration was
improved with the use of both organic and plastic mulches as compared to bare soil
For example plastic mulches will reduce the impact of rainfall and sprinklers on the
surface of the soil and disperse their impact which results in more moisture
infiltration
Depending on the mulch material soil temperature may be either raised or
lowered by the presence of a mulch Most organic mulches absorb incoming solar
radiation and actually cool the soil beneath them However soil temperature beneath
the mulch is a function ofmulch moisture content and mulch thickness In synthetic
mulches color plays an important role in determining the effect of mulch on soil
temperature Clear polyethylene mulches and row covers are currently being used as
a means ofpest control in many bareroot nurseries (Hildebrand 1989) This practice
developed in the Middle East is commonly referred to as soil solarization The clear
film acts as a greenhouse film allowing the high energy shortwave radiation in but
preventing the long-wave reradiation from passing skyward This results in the soil
absorbing the energy associated with the light thus heating the soil Opaque and
colored synthetic mulches may also heat the soil Dark colored and black mulches
can readily absorb solar radiation and heat up significantly in areas ofhigh solar
9
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
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ij 1 i
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62
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63
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64
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McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
radiation such as the Southwest United States It has been suspected by several
investigators that dark mulches can absorb enough heat to effect tree survival (Maiers
1997 McDonald et al 1994) Black mulch acts as an efficient absorption material for
ultraviolet visible and infrared wavelengths of incoming solar radiation (Loy et al
1989) Due to the thermal conductivity of the soil which is related to moisture
content a large portion of the energy absorbed by the black plastic is transferred to
the soil by the process ofconduction (Loy et al 1989) It was found that when the
temperature of the soil was measured a difference as high as 2degC was found between
the loosely covered and the tightly covered black plastic mulch used to cover the soil
(Loy 1989 Ham et al 1993 Lamont 1996)
Splittstoesser and Brown (1991) stated that under black mulch soil
temperatures increased 10-15degC above those of bare soil Temperature beneath black
polyethylene mulch were 4degC warmer than bare soil (Loy and Wells 1990) Mean
soil temperatures under black mulch decreased with depth (Lopushinsky and Beebe
1976)
Agriculture in the Middle Rio Grande Region
In 1540 the Spanish explorer Coronado documented Indians using irrigation
methods in the middle Rio Grande Valley to grow corn and beans Today the
population is concentrated along the Rio Grande in an area approximately six
kilometers wide and forty-two kilometers long Most of the area is used as range
10
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
land Also the main irrigated crops grown are alfalfa and permanent pasture Smaller
farms grow com barley wheat sorghum chile lettuce and fruit orchards
The Los Lunas area is a physiographic trough (Rio Grande graben) which is
fifty-four kilometers wide and bordered by the Manzano Mountains on the east and
the Lucero uplift on the west A majority of soils in Los Lunas were formed by a
variety of alluvial deposits Some of these alluvium deposits were altered by wind
which results in carbonate deposits Other types of soil contain weathered basalt
granite schist limestone sandstone and shale and alluvium deposits (Pease et al
1975) Due to course changes of the Rio Grande the soil tends to be a complex
combination ofsand silt and clay This area has an arid climate and most of the
winter moisture comes from the Pacific Ocean while summer moisture comes from
the Gulf of Mexico This area has clear sunny weather and low relative humidity
three-fourths of the daylight hours Surface winds are controlled by the topography
of the valley with stronger winds late in the winter and in the spring which can cause
periods of blowing dust (Pease et al 1975)
Los Lunas is situated at an elevation of 1475 meters and the average annual
rainfall of 18-25 centimeters which falls during the growing season from April
through October 15th Seventy-seven percent ofannual rainfall occurs during the
growing season (Hooks 1996 Pease et al 1975)
11
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
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62
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Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
Arizona Cypress
Long (1977) stated that the genus Cupressus has shown characteristics which
are promising afforestation plantings in both arid and semi-arid areas Arizona
cypress is drought resistant once it is established and can be grown in alkaline soils
Arizona cypress is found in both the canyons and mountains of southeast and central
Arizona and southwest New Mexico and is found at an elevation of between 1200 and
2000 meters (Tidestrom and Kittell 1941) Traditionally the genus Cupressus has
been used for landscaping and Christmas trees and more importantly for erosion
control and windbreaks (Young and Young 1992)
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
MATERIALS AND METHODS
Study Site
This study utilized an experimental windbreak planting established in Los
LUIlas New Mexico The planting site was part of a state-wide windbreak
establishment project conducted in 1994 and 1995 (Maiers 1997) The original study
examined the influence ofdifferent site preparation techniques and stock sizes of
container grown Arizona cypress (Cupressus arizonica) and eldarica pine (Pinus
brutia var eldarica) Only those treatment combinations involving the largest (656
ml Deepot Steuwe and Sons Corvalis OR) Arizona cypress were used in the present
study
This study was conducted at the New Mexico State University - Los Lunas
Agricultural Science Center in Los Lunas New Mexico (latitude 34deg46 longitude
106deg45) Average annual precipitation ranges from 22 to 25 cm (Hooks 1996) The
soil of the planting site is a loamy sand (872 sand 46 silt 82 clay Maiers
1997) Average monthly soil temperature ranges from 33degC in January to 29degC in
July (Hooks 1996) The site was leveled using a laser level prior to the initial
planting in 1995 The site was initially dominated by sagebrush (Artemesia fllifolia)
Site Preparation Treatments
Four site preparation treatments were monitored in this study These
treatments included an undisturbed control a shallow V -ditch a synthetic weed
barrier and a combination of the V-ditch treatment with the weed barrier laid over the
V -ditch The V -ditch treatment makes use of a shallow trench two meters wide The
13
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
base of the V is one meter in from each edge of the trench The V -ditch treatment
was installed using a blade on the back of a fann tractor
The weed barrier consists of a tightly woven synthetic burlap which allows for
water penetration and prevents weed growth To accommodate the seedling slits
were cut into the weed barrier All seedlings were planted one meter in from the edge
of all site preparation treatments All treatments were two meters wide and 15 meters
longs
The current study began on June 201997 and ran through August 11997 On
the first day of the study the entire plot was irrigated with a minimum of 15 cm of
water from a flood irrigation system The experimental design was randomize
complete block design with three blocks
Plant Measurement
Seedling height was measured from the ground to the tallest growing tip of the
established Arizona cypress seedlings remaining in the study Height was measured
to the nearest centimeter using a meter stick Seedling height and survival were
measured only for those seedlings planted as 656 ml Deepots Height and survival
data were analyzed using analysis ofvariance (PROC GLM SAS Institute 1990)
Treatment separation was done using the LSD means separation procedure (PROC
GLM SAS Institute 1990)
Soil Moisture Measurement
Soil moisture content was measured for each site preparation treatment at
three depths at three points relative to the center of the site preparation treatment
14
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
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Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
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Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
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Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
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64
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65
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66
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67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
The three points relative to the center were 0 30 and 60 cm from the center of the
treatment At each point samples were taken from depths of 10 20 and 30 cm This
sampling design generated a grid ofnine soil moisture measurement per site
preparation treatment per block Soil samples were taken using a bucket sand auger
removed from the auger and placed into pre-weighed ointment cans Lids were
immediately placed onto the cans following filling with samples Cans were then
transported to the laboratory where they were weighed to the nearest milligram using
a top loading balance Lids were then removed and the cans containing the samples
were placed into a drying oven at 105degC for 24 hours or until a constant weight was
achieved Samples were then removed from the oven and placed on a laboratory
bench until they cooled to room temperature and were reweighed as described above
Soil water content (w) was calculated as the mass ofwater per unit mass of dry soil
using the following equation
mass of wet soil - mass of dry soil W = -------------------------------------------shy
mass of dry soil
Soil moisture content was measured twice weekly throughout the duration of
this study (34 days) Measurement ofsoil moisture was terminated due to heavy
rainfall prior to the eleventh sample date No other appreciable (gt 5 mm)
precipitation occurred prior to this rain episode
To prevent sample contamination with backfill sampling was conducted using
both sides of the treatment On alternating days samples were taken from opposite
sides of the treatment Samples were taken at 20 cm intervals along the axis of the
15
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
treatment The final sample (tenth sample date) was located approximately two
meters from the initial sample point Upon reviewing the data this technique was
found to be sufficient in minimizing sample contamination A total of twelve samples
had to be discarded due to contamination
Soil water content was then converted to soil moisture pressure potential by
using a pressure release technique (Klute 1986 Smith and Mullins 1991) Appendix
1 contains the three pressure release equations for the three soil moisture sampling
blocks used in this study Due to the low power of this sampling design only
swnmary data (mean and standard error) are presented
Soil and Air Temperature Measurements
Soil and air temperatures were measured throughout the duration of this study
using remote data loggers (Optic StowAway Temp Onset Computer Corporation
Pocasset MA) Data loggers were programmed to record temperature every hour
Due to limited availability ofdata loggers the entire study could not be monitored
Therefore only portions of two of the three blocks were measured Data logger
locations are provided in Table 1 Due to the restricted sampling design only
summary temperature data are presented
Competing Vegetation Measurements
At the end of the soil moisture sampling period competing vegetation was
measured using a line intercept method (Phillips 1959) This technique involved
suspending a ten-meter string along the long axis of a site preparation treatment The
string was subdivided into one meter increments The string was suspended 30 cm
16
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
off of the soil surface The distance a plant crown intercepted the line was recorded
to the nearest centimeter Three transects were taken for each treatment by block
combination The three transects were the center of the treatment 50 cm from the
center and on the edge of the treatment Weed competition data was analyzed using
analysis ofvariance (PROC GLM SAS Institute 1990) Treatment separation was
done using the Bonferroni means separation procedure (PROC GLM SAS Institute
1990)
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
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62
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Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
Table 1 Temperature probe locations used in the study
ITreatment Location Blocks i
middot Control Plat crown 1
Control
Control
1 cm below soil surface
23 cm below soil surface
12
12 i
Control 38 cm below soil surface 1
Weed Barrier 1 cm below soil surface 12
Weed Barrier i
23 cm below soil surface 1
V-ditch 1 cm below soil surface 12 I
V-ditch
V -ditch Weed Barrier
V -ditch Weed Barrier
V -ditch Weed Barrier
23 cm below soil surface
Plat crown
1 cm below soil surface
23 cm below soil surface
12
1
12
12
I
I
I I
V -ditch Weed Barrier 38 cm below soil surface 1
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
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Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
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McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
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65
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66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
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67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
RESULTS
Survival and Growth
Two-year survival was not influenced by site preparation treatment (Table 2
Figure 1) Two-year height was influenced by site preparation treatment (Table 3)
Two-year height improved as site preparation intensity increased (Figure 2)
Seedlings growing in the combined V -ditch and weed barrier treatment had two-year
heights greater than either treatment alone and two times the height of seedlings
growing in the control treatment The two intermediate site preparation treatments
had two-year heights exceeding control seedlings in excess of 52 (Figure 2)
Soil Moisture
The initial irrigation completely wetted all loci evaluated in the study (Figures
3 - 12) Aliloci in all site preparation treatments remained moist through the fourth
collection date or 13 days into the dry down period The upper three loci loci 1 4
and 7 began to show signs of drying by the fifth collection date or day 17 into the dry
down period in all but the V -ditch weed barrier combined treatment (Figures 3 6 9)
The most intensive site preparation treatment the combination of V -ditch and weed
barrier did not show signs of appreciably (gt03 Mpa) drying until 24 days after the
last irrigation (Figure 12) The second tier of loci (20 cm below the surface) began
drying down much slower with the V -ditch treatment alone appearing to dry down
faster than the other two site preparation treatments and the control However it was
not until the eighth collection period or 27 days into the dry-down period that any
appreciable drying occurred in the V -ditch alon treatment
19
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
Table 2 Analysis of variance table for 2-year survival percent ofArizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums of Sguares Fvalue PrgtF N 0
Block 2 31667 032 07365 Site Prep 3 382500 259 01379 Error 6 295000 Corrected Total II 709167
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
100
80
~ 60-m gt ~
J 40(JJ
20
o
Figure
1
1
I
Control V-Ditch Weed V-Ditch
Barrier Weed Barrier
Treatment
1 The effect of site preparation on 2-year (percent) survival of Arizona cypress (Cupressus arizonica) (mean plusmnSE)
21
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
Table 3 Analysis of variance table for 2-year height of Arizona Cypress seedlings under four site preparation treatments in Los Lunas NM
Source df Sums ofSguares F value PrgtF N N Block 2 11896 033 07334
Site Prep 3 4497360 8234 00001 Block x Site Prep 6 109237 031 09285 Error 61 3562874 Corrected Total 72 8204704
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
LITERATURE CITED
Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
McMinn R G 1981 Root growth capacity and field performance ofvarious types and sizes of white spruce stock following outplanting in the central interior of British Columbia Canadian Forest Research Center pp38-4l
Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
Pease DS Diebold CH Roath AJ and Stevenson A 1975 Soil Survey of Valencia County New Mexico Eastern Part US Dept Agr pp 112-121
Phillips EA 1959 Methods of Vegetation Study Holt Rinehart and Winston Inc New York 107 pp
65
Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
SAS Language Referance 1990 Version 6 First Edition SAS Institute IncCary NCUSA 1042 pp
Skujins J 1991 Semiarid Lands and Deserts Soil Resource and Reclamation New York Marcel Dekker Inc668 pp
Smith K A and Mullins C E (Eds) 1991 Soil Analysis Physical Methods New York Marcel Dekker Inc
Spedding CRW 1981 Vegetable Production on Small Farms Overseas Bristol Great Britain J W Arrowsmith Ltd
Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
Stafford CW Torbert JL and Burger JA 1985 An evaluation of site preparation methods for loblolly pine regeneration on the Piedmont Paper presented at Southern Silvicultural Research Conference Atlanta Georgia
Suleman S 1992 Comparison ofRainwater Harvesting Systems for Increasing Forage in Arid Rangelands ofPakistan PhD dissertation New Mexico State University Las Cruces NM
Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
United States Department ofAgriculture 1995 New Mexico Agricultural Statistics 1995 70 pages
United States Department of Agriculture 1996 New Mexico Agricultural Statistics 1996
Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
Walton K 1969 The Arid Zones Chicago Aldine Publishing Company pp 1-17
West NE 1983 Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts New York Oxford
Westwood NM 1993 Temperate Zone Pomology Portland Oregon Timber Press pp 159-177
White GF 1960 Alternative uses oflimited water supplies In Arid Zone Research - XVIII - The Problems of the Arid Zone Proceedings of the Paris Symposium Oberthur France Imprimeries pp 411-421
Young JA and Young CG 1992 Cupressus L In Seeds ofWoody Plants in North America Timber Press Inc
67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000
140
120
100
--E
-0 80
c C)
CD 60 J J
40
20
0 Control
j
V-Ditch Weed Barrier
Treatment
t
V-Ditch Weed Barrier
Figure 2 The effect of site preparation on 2-year height growth of Arizona cypress (Cupressus arizonica) (mean + SE)
23
--
2
-m 0shy
i
J ()
() 1 0
i
o
c=J Control ~ V-ditch ~ Weed Barrl~r I8888B8 V-ditch + Weed Barrier MD - Missing Data
MO~~ll 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 3 Chang~s in soil moisture potential at loci 1 (60 em from treatment center 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tv VI
-(U Q
~-~ J tn
Control ~ Vcfitch ~ Weed Barrier
2 J ~ Vcfitch + Weed Barrier
tn 1 ~ a
o I P= -1 nzrnr JifN ~ I If9 I ~ I fR I ~ I fI8 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 4 Changes in soil moisture potential at loci 2 (60 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-ca a ~-~ J U)
f=J Control ~ V-ditch ~ Weed Barrier
2 -I IIllB8 V-ditch + Weed Barrier
U) 1 ~ a
o I -r= ~ ~ ItpEI Iqmt I~ 1qst8 I~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 5 Changes in soil moisture potential at loei 3 (60 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N -J
- as c E-e J (f)
cJ Control ~ V-ditch ~ Weed Barrier
2 -I all8BB8 V-ditch + Weed Barrier MD - Missing Data
~ 1 a
o I ~pm I IAfC I fISI ~ I fS1 I ~ I ~ I fU I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 6 Changes in soil moisture potential at loci 4 (30 cm from treatment center 10 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 00
-m Q
iE-~ J
Control ~ V-ditch ~ Weed Barrier
2 -I1l8lISBI V-ditch + Weed Barrier
m ~ 1
D
o I -P=shy 12fih I flI I ~ I ~ I ~ I FfII I ff I ~ 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 7 Changes in soil moisture potential at loci 5 (30 em from treatment center 20 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
N 0
-m a ~ -
~
r=J Control ~ V-ditch ~ Weed Barrier
2 -I ml8B8 V-ditch + Weed Barrier
J rn rn ~ 1 a
o I shy r CrrfV I ~ I JIIi (INKlI
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 8 Changes in soil moisture potential at loci 6 (30 em from treatment center 30 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
II I
w o
rJ Control ~ V-ditch ~ Weed Barrier
2 -l ~ V-ditch + Weed Barrier
-~ lE-~ J gJ ~ 1
Dshy
_TIII
o I --r= rnf= ampfD I tfR I poundfill ~ I f4iI I ~ IpoundfI IQI 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 9 Changes in soil moisture potential at loci 7 (center of treatment 10 em depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
w
C=J Control ~ V-ditch ~ Weed Barrier
2 -I1B8lB88 V-ditch + Weed Barrier
-~ 5-shy l f) f)
1 a
o I jiIF I I flIII I Vf VfD I nttJl4 I I P I 4
3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 10 Changes in soil moisture potential at loci 8 (center of treatment 20 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
W N
(=J Control ~ V-ditch ~ Weed Barrier
2 -I ~ V-ditch + Weed Barrier
-m Q ~- l f) f)
1 a
o I = I - r 0 F I1zti I~ I~ ~ I~ I~ IfPII 3 6 10 13 17 20 24 27 31 34
Days After Irrigation
Figure 11 Changes in soil moisture potential at loci 9 (center of treatment 30 cm depth) from 0 to 34 days after last irrigation for the four site preparation treatments evaluated in this study (mean + 1 SE)
tJ tJ
I ~ ~
- ~ -----~ -~
-----shy
Control 27 Days After Ir(igation
V-ditch _ xgt~ sect ___~_ io
i =-
w ier __ bull__ ~~ii
--shy --shy
Control
_ 00 - 03 Mpa _ 04middot06 Mpa
07 - 09 Mpa IIIIII 10 shy 12 Mpa
cJ 13 - 15 Mpa cJ gt 150 Mpa
Figure 12 Graphic (fill) display ofdry down patterns for all nine loci over the duration of the study The seedling would be located at the upper right
comer ofeach grid
Only on the last collection date or 34 days since the last irrigation that any
appreciable drying occurred in the second tier loci of the control plots Soil drying
never exceeded 03 Mpa in the second or third tier loci in the weed barrier alone or
combined V -ditch and weed barrier treatments In the control and weed barrier
treatments alone the lowest tier of loci (30 cm) were not dried below 03 Mpa
Drying in the upper loci began at the two periphery loci (loci 1 and 7) and
moved inward toward loci 4 This drying trend was most rapid in the two
intermediate site preparation treatments (Figure 12) This pattern ofdrying started at
collection date 5 with the exception of the combined V-ditch and weed barrier
treatment where the trend began 7 days later At the seventh collection date when
signs ofappreciable drying (at loci 7) in the most intensive treatment were beginning
the other two site preparation treatments and control had appreciable drying in all the
loci in the upper tier (Figures 3 6 9 12)
Crown and Soil Temperatures
No differences occurred in daily low temperatures in the crowns ofArizona
cypress seedlings growing in the control and V -ditch weed barrier treatments (Figures
13 14) The daily high temperature was consistently 1 to 2degC higher in the control
seedling versus the tree growing in the combined V -ditch and weed barrier treatment
The seedlings in the combined V -ditch and weed barrier treatment had daily high
temperatures going from 38degC at the beginning of the study to around 40degC at the end
of the study The
34
shy0 Q-~ l-as Q) 0 E ~
50~------------------------------------------~
40
30
20
10 -shy Minimum Crown -0- Maximum Crown ---- Minimum Air -9- Maximum Air
O~--~----~~----~----~----~----~------~~ ~ ~ ~ ~ ~ 0gt-co N co ft 0 N 2 0 s s- - rco 0 0 0 0 0 0
Calendar Date
Figure 13 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
35
50~----------------__________________________~
40
~- 30 ~ I-lt0 Q) Co
20E Q) r
10 - Minimum Crown -ltgt- Maximum Crown -shy Minimum Air -shy Maximum Air
O~--~----~------~----~----~----~----~~ ~ 0) ~ ~ ~ ~-(0 (II co It 0 ~ i2 0
~ ~ - -(0 0 0 0 0 0 0
Calendar Date
Figure 14 Daily high and low temperatures in the ambient air and in the crown of Arizona cypress (Cupressus arizonica) growing in V-ditch amp weed barrier plots
36
control seedlings averaged about 40degC throughout the study with greater day to day
fluctuations than for the other seedlings
In all four site preparation treatments soil temperature at the soil surface
increased as the dry-down period progressed (Figures 15 16 17 18) Again the daily
low temperatures did not differ among the three site preparation treatments and
controL The weed barrier alone treatment had daily high temperatures comparable to
control whereas the V -ditch alone and combined V -ditch and weed barrier
treatments were consistently cooler than either the control or weed barrier alone
treatment
As was expected daily temperature fluctuation was small at the 23 cm depth
Almost no difference laquo10degC) occurred in either the daily high or low soil
temperatures among treatments at this level (Figures 19 20 2122) The same trend
occurred at the 32 cm level with no difference in daily high or daily low temperature
between the control and the V-ditch weed barrier combination treatment (Figures 23
24)
Weed Competition
Site preparation treatments did not effect weed coverage along the edge of the
treatments nor 50 cm from the center of the treatments (Tables 45) The combined
weed barrier and V -ditch treatment did result in significantly less weed coverage
along the center axis of the site preparation treatment (Tables 6 7) The two
treatments alone did not reduce weed coverage relative to control along this center
axis The majority of the weed competition in all transects was Salsoa kali and
37
Sporobolus aeriodes (Figures 25 26 27) The relative proportion of these two
species increased within treatments containing weed barrier in the two internal
transects (Figures 26 27) This was due to the crowns of these two species growing
over the top of these treatments not through them
38
50
45
40 0 -()- 35 l 30 (0 Q) 25 c E Q) 20 I shy
150 Cf)
10
5
0
- Minimum Daily Temperature Block 1 --0shy Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
Ol ~ Ol Ol - lt0 ~ N ~ - CiS qo ~ 2 ~ 2 ~-
Ol
~~ 0 0 0 -0 0 0
Calendar Date
Figure 15 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
39
50
45
40 0 -() 35
G) l-to G) c E ~ 0 fJ)
30
25
20
15
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - - Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
CJ) CJ) ~ (l) ~ ~ N ~- - co oq- ~- C 52 0 shyto (l) C0 C
0 0 - - 0 ~ 0 0
Calendar Date
Figure 16 Daily high and low temperatures 1 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch plots
40
50
45
40 0shy
35pound ~ 30l
~ CI) 25 Co E CI) 20 tshy
150 en
10
5
0
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S en enmiddot S en en lt0 (J Ci3 qo C5 g SO SO ~ ~ 0 0 0 0 0 0
Calendar Date
Figure 17 Daily high and low temperatures 1 em below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
41
50
45
40 0 --Q 35 l 30a ~ 25amp E 20 ~ middot0 15 (J)
10
middot5
0
-- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2
S r-- r-- r-shy10 S r--
N S ltllco St ltI SS2 C3S2 I shy~ I- r-- N0 0 0 ~ 0 0
Calendar Date
Figure 18 Daily high and low temperatures 1 cm below the soil sUrface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
42
50
45
40 Cl -()- 35 e J 30 ~ ltII 25 c E 20 0 15 en
10
5
0
~ ~~~~8a=e--=--~ -~ea
v
- Minimum Daily Temperature Block 1 -- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 - Daily Maximum Temperature Block 2
en ~ ti Ii S eniI~
II) ~ Q Q
~ S2 t Q -Q ~ Q Q
Calendar Date
Figure 19 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in control plots
43
- Minimum Daily Temperature Block 1 --- Maximum Daily Temperature Block 1 - bull Minimum Daily Temperature Block 2 -- Daily Maximum Temperature Block 2 Ol $ S
N S - co~ ~ ~ S (0 52 52 0 N0 0 - ~ 0 0 shy0
Calendar Oate
Daily high and low temperatures 23 cm below the soil sUrface of Arizona cypress(Cupressus arizonica) seedlings growing in V-ditch plots
44
50
45
40 Q -U 35- 30-e co Q) 25
~ 20E 1515
en 10
5
0
- Minimum Daily Temperature - Maximum Daily Temperature
Calendar Date
Figure 21 Daily high and low temperatures 23 cm below the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in weed barrier plots
45
50
45
40 0 -()- 35 tIs 30-e CI) 25 Q
E 20 ~
15=a ()
10 - Minimum Daily Temperature Block 1
5 Maximum Daily Temperature Block 1-0shy
- bull Minimum Daily Temperature Block 2 0 -- Daily Maximum Temperature Block 2
i (l) i i
Cl i ire ~ itlt0 ca S2 0 ~ 0 ~ 0 ~ ~0 ~ 0 0 0 0
Calendar Date
Figure 22 Daily high and low temperatures 23 cm beow the soil surface of Arizona cypress (Cupressus arizonica) seedlings growing in V-ditch and weed barrier plots
46
0 -U-~ 2 nI Q) Q E ~ g C)
50
45
40
35
30
25
20
15
10
5
0
_ 0-0-0- 0-0-0 bull bull bull bull bull bull bull bull bull ~ ~ -- ~ - -------O~-_t
- Minimum Daily Temperature --- Maximum Daily Temperature
Calendar Date
Figure 23 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus arizonica) seedlings growing in control plots
47
50
45
-- 40 0 ()- 35 ~ J 30 (1l 25 0 E 20 ~
15 en 0
10
5
0
bull
-- Minimum Daily Temperature
- Maximum Daily Temperature 0) Oi $ -0) 0) 0)
N (0 0)
CO t S2 0 - ~ - CO 0 0 t t0 -0 0 - 0 0
Calendar Date
Figure 24 Daily high and low temperatures 38 cm below the soil surface of Arizona Cypress (Cupressus
arizonica) seedlings growing in V-ditch and weed barrier plots
48
Table 4 Analysis of variance table for weed coverage along the edge of site preparation treatments in Los Lunas NM
Source df Sums of Sguares F value Prgt F ~ 0
Block 2 157152 111 03900Site Prep 3 164140 077 05514Error 6 426277 Corrected Total 11 747570
Table 5 Analysis of variance table for weed coverage 50 cm from the center of site preparation treatments in Los Lunas NM
Source df Sums of Squares F value PrgtF v 0
Block 2 109274 067 05466 Site Prep 3 757266 309 01113 Error 6 440273 Corrected Total 11 1356812
Table 6 Analysis ofvariance table for weed coverage along the center of site preparation in Los Lunas NM
Source df Sums of Sguares F value Prgt F VI- Block 2 244116 280 01382
Site Prep 3 1435510 1099 00075 Error 6 261350 Corrected Total II 1940977
Table 7 Mean value for weed coverage along the center ofsite preparation treatment in Los Lunas NM Treatment not covered by the letter are different at alpha = 005
Treatment Mean Coverage () LSD Results
Control V-Ditch Weed Barrier V-Ditch amp Weed Barrier
10427 8407 3517 2013
A A B
B B
52
120-------------------------------------------~cJ Sasoa kali GSSl Sporobous aeroides
100 E2Zd Other spp
-f-c 80 o
0
~
~ 60 o (J tJ) Q)0 40 Q) Q
en 20
Control V-clitch Weed Barrier
Site Preparation Treatment
V-clitch Weed Barrier
Figure 25 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the edge of the site preparation treatments averaged across a three blocks
53
120~==~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 E2ZJ Other spp
-~-c 80 o
0= ~
~ 60 o () en ~ 40
8 (J)
20
Control V-ditch Weed Barrier
Site Preparation Treatment
V-ditch Weed Barrier
Figure 26 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage 50 cm from the center of the site preparation treatments averaged across all three blocks
54
120~~~~~__________________________________~
cJ Sasoa kali ISSSl Sporobolus aeroides
100 fZZI Other spp
-~ shyr 80 2shyiii o ~ 60 o
() til
~ 40
8 en 20
Control V-clitch Weed V-ditch Barrier Weed Barrier
Site Preparation Treatment
Figure 27 Percent coverage for Sasoa kali Sporobous aeroides and other plant coverage along the center of the site preparation treatments averaged across all three blocks
55
-DISCUSSION
In the present study none ofthe site preparation treatments evaluated
improved two-year survival of Arizona cypress Even though there appeared to be
over a two-fold improvement in survival for the combined V -ditch and weed barrier
treatment relative to the control the overall variability among the blocks prevented
detection ofthis difference In previous studies using plastic mulches mulches have
been shown to improve survival (Lopushinski and Beebe 1976) However the 30
improvement in survival due to the weed barrier alone treatment in this study was
twice the survival improvement found in the same treatment by Loupushinski and
Beebe (1976) Others have found a lack of detectable difference in survival when
comparing plastic film mulches to untreated controls (Van Sambeek et al 1995
Traux and Gagnon 1993 McDonald et al 1994)
Studies using scalping or mechanical vegetation removal have found these
techniques to improve early two-year survival (Capo-Arteaga and Newton 1991)
However the wide range ofvariability between blocks resulted in the inability of the
over 30 improvement in survival to be significant However mechanical andor
chemical removal ofcompeting vegetation has been shown to be a factor in
improving survival of seedlings planted in dry sites (Capo-Arteaga and Newton
1991)
The improvement in two-year height growth as site preparation intensity
increased in the present study is similar to that reported by others Using a black
plastic (polyethylene) mulch improved the height growth ofbutternut (Juglans
56
cinerea L) bur oak (Quercus macrocarpa Michx) and white ash (Fraxinus
americana L Traux and Gagnon 1993) Similar improvements in growth have been
reported for other deciduous and evergreen species (VanSambeek et al 1995
McDonald et al 1994) Authors have attributed this improvement to several
environmental modifications resulting from the site preparation used including
improved nutrition (Traux and Gagnon 1993) improved moisture availability
(VanSambeek et al 1995 Fleming et al 1994 1996 Parfett et al 1980) and
improved root zone temperature before and after the growing season (Davies 1975)
Only the top two tiers of soil loci monitored in this study had any appreciable
drying over the course of the study In the case of the second tier of soil (20 cm
below the surface) this drying occurred only in the control and V -ditch alone
treatment on the last three sampling periods Only the most intensive site preparation
treatment the V -ditch weed barrier combined treatment appeared to delay surface
(l0 cm) soil drying in this study However the two site preparation treatments
applied independently did not forestall surface drying relative to the control
treatment While most reported studies show that use of a plastic mulch will improve
soil moisture no studies have examined the dry down scenario in either the absence
ofadditional moisture or in a semi-arid environment as was done in this study
In most reported studies illustrating the benefit of plastic mulches in retention
of soil moisture the material evaluated is a solid polyethylene sheet (VanSambeek et
al 1995 Fleming et al 1994 1996 Parfett et al 1980) In the present study a woven
(porous) polyethylene material was used Appleton et al (1990) using the same
57
material found the fabric reduced soil moisture deficit relative to bare soil However
two important differences exist between the two studies First the reference point for
soil moisture measurement used in the Appleton et al (1990) study would have been
located in the second tier of loci in the present study where difference were just
beginning to become evident after 4 weeks Secondly the value reported in the
Appleton et al study was a season long average Had the rain which occurred 35
days into the present study been delayed we expect the curves of soil moisture which
were beginning to diverge would have continued to at an increasing rate
The pattern of dry down regardless of time of initiation seen in all three site
preparation treatments and the control treatment may have been caused by the
associated or adjacent weed competition A likely explanation has to do with the
build up of weed competition at the edges of the weed barrier treatments or within the
V -ditch treatment The weeds growing along the edge of the weed barrier treatment
were larger in stature than individuals of the same species growing in the control and
V -ditch treatments (personal observations) This phenomenon has been reported by
others (Traux and Gagnon 1993 Davies 1988a 1988b) The weed population
adjacent to the treated area may have extended root systems growing under the weed
barrier layer on the soil surface This root mass would result in the depletion of the
water in this portion of the soil This theory is also supported by the pattern of soil
depletion moving in from the edges towards the center of this upper tier of soil
(Figure 12) The depletion from the center would be resulting from the seedlings and
58
associated weeds growing through fabric openings made for the trees at the time of
planting
The large variability within each loci by treatment for a given sampling time
is likely due to the nature of the sampling procedure The systematic sampling
procedure was adhered to regardless of the presence ofvegetation This may have
resulted in some loci being sampled directly under a plant in one or two blocks while
the other sample or samples may have been under minimal influence of a plant This
could result in the large fluctuations in soil moisture observed in this study
While published reports exist that solid black polyethylene plastic mulches
increase the soil temperature beneath the mulch (Loy and Wells 1990) others have
reported no differences in soil temperature using these mulches (Tonn and Graham
1982 Trinka and Pritts 1992) In the present study using a woven weed barrier no
differences were detected in the canopy of the seedling or the soil beneath the weed
barrier or V -ditch treatment The same lack ofsoil temperature effect has been
documented in Virginia using the same weed barrier (Appleton et al 1990)
While no differences in weed canopy coverage occurred along the edges of
the site preparation treatments there was a noticeable increase in the stature of the
weeds growing along the two weed barrier containing treatments The weeds
growing in the two weed barrier containing treatments were noticeably taller and
broader in stature This resulted in the failure to detect differences between the site
preparation treatments along the transect 50 cm from the center of the treatment No
weeds were growing through the weed barrier however the large crowns of the
59
weeds growing along the edge grew over this area of the treatment resulting in
measurable canopy coverage In some instances this was also the case along the
transect going down the center of the treatment However along this transect weeds
growing out of the holes cut for the seedlings were also detectable In the V -ditch
weed barrier treatment the larger seedlings appeared to out compete the weeds and
the weed stature was lower than in the weed barrier alone treatment
CONCLUSIONS
This study a continuation of Richard Maiers original project on tree
establishment in semi-arid regions has illustrated that proper site preparation and
rainfall harvesting can improve trees growth in such areas While this study was
unable to detect significant difference in soil moisture profiles beneath the site
preparation treatment it appears that the combination of the V -ditch and weed barrier
treatments may improve soil moisture reserves in a prolonged drought The effect of
the two site preparation treatments alone while showing improved growth appeared
to lose soil moisture at a rate comparable to untreated controls
There appears to be no effect of using synthetic weed barrier on the
temperature immediately above or below the weed barrier in the present location
The effect of the weed barrier in controlling competing vegetation may be negating to
a certain extent by the enhancement ofplant growth along the edge of the treatment
r
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Appleton BL Derr JF and Ross BB 1990 The effect of various landscape weed control measures on soil moisture and temperature and tree root growth J Arboriculture 16 264-268
Black AL and Greb BW 1961 Nitrate accumulation in soils covered with plastic mulch Agronomy Journal pp 366
Borland J and Weinstein G 1989 Mulch Is it always beneficial Grounds Maintenance pp II-IS
Brown D Brockman H and Houck MJ 1992 In Society ofAmerican Foresters 1992 National Convention October 1992 Richmond Virginia pp 260-264
Capo-Arteaga M and Newton M 1991 Survival and growth of five species of Pinus seedlings after different approaches to competition control bridging studies between Oregon and Mexico New Forests S219-238
Crane JC and Maranto J 1988 Pistachio production Cooperative Extension University of California Division of Agriculture and Natural Resources Publication 2279
Davies JW 1975 Progress in Biometeorology Div C Vol I Swets and Zeitlinger BV Amsterdam 379-389
Davies RJ 1988a Sheet mulching as an aid to broadleaved tree establishment I The effectiveness of various synthetic sheets compared Forestry 61 89-IOS
ij 1 i
Davies RJ 1988b Sheet mulching as an aid to broadleaved tree establishment II Comparison ofvarious sizes ofblack polythene mulch and herbicide treated spot Forestry 61 107-124
Fereres E and Goldhamer DA 1991 Plastic mulch increases cotton yield reduces need for preseason irrigation California Agriculture 4S(3) pp 2Sshy28
Fisher JT and Montano JM 1977 Establishment of tree plantation in northern New Mexico In Proceedings of the 29th Annual Meeting Forestry Committee Great Plains Agricultural Council June 1977 Albuquerque NM pp 167-178
62
Fleming RL Black TA and Eldridge NR 1994 Effects of site preparation on root zone soil water regimes in high-elevation forest clearcuts Forest Ecology and Management 68 173-188
Fleming RL Black TA and Adams RS 1996 Site preparation effects on Douglas-fir and lodgepole pine water relations following planting in a pinegrass-dominated clearcut Forest Ecology and Management 83 47-60
Haase DL and Rose R 1990 Moisture stress and root volume influence transplant shock Preliminary results General Technical Report Rocky Mountain Forest and Range Experimental Station (200) pp 201-206
Haase DL and Rose R 1993 Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-Fir seedlings ofvarying root volumes Forest Science 39(2) pp 275-294
Hallgren SW and Helms JA 1988 Control ofheight growth components in seedlings of California red and white fir by seed source and water stress Can J For Res Vol 18 pp 521-529
Ham J M Kluitenberg GJ and Lamong WJ 1993 Optical properties of plastic mulches affect the field temperature regime J Amer Soc Hort Sci 118(2) pp188-193
Harris R W 1992 Arboriculture New Jersey Prentice Hall Career amp Technology PP 674
Herrera El 1996 Mulches for gardens and landscapes (Rev) Cooperative Extension Service Guide H-121 New Mexico State University Las Cruces NM
Herrera E 1997 Rev Growing pistachios in New Mexico Cooperative Extension Service Circular 532 College of Agriculture and Home Economics New Mexico State University Las Cruces
Hildbrand D M 1989 A review of soil solar heating in western forest nurseries in TDlandis ed Proc Intermountain forest nursery association Agul4-18 1989 Bismarck ND pp 49-51
Hooks R F 1996 Thirty-eight years ofclimatological data 1957-1994 Agricultural Experiment Station Research Report 711 New Mexico State University Las Cruces NM
63
Huszar DC and Piper SC 1986 Estimating the off-site of wind erosion in New Mexico Journal of Soil and Water Conservation 41(6) pp 414-416
Jobidon R 1990 Short-term effect of three mechanical site preparation methods in species diversity Tree Planters Notes 41(4) pp 39-42
Klute A (Ed) 1986 Methods ofsoil analysis Part 1 Agronomy pp 404-408
Lamont WJ Jr 1996 What are the components ofa plasticulture vegetable system HortTechnology 6(3) pp150-154
Lantagne DO and Burger JA 1987 Comparison of site preparation methods for weed control in loblolly pine (Pinus taeda) plantations Weed Science 35590-593
Lee R D 1994 Weed management in pecans Cooperative Extension Service Guide H-632 New Mexico State University Las Cruces NM
Long RV 1977 Desert Forestry Potential in Nevada - Phase 1 In proceedings of the 29th Annual Meeting - Forestry Committee Great Plains Agricultural Council June 1997 Albuquerque New Mexico pp95-100
Lopushinsky W and Beebe T 1976 Effect of black polyethylene mulch on survival of Douglas-Fir seedlings soil moisture content and soil temperature Tree Planters Notes Summer 197617
Loy B Lindstrom J Gordon S Rudd D and Wells O 1989 Theory and development ofwavelength selective mulches Proceedings of the National Agricultural Plastics Conference pp 193-197
Loy B and Wells O 1989 IRT mulch High-tech at ground level American Vegetable Grower pp 14-17
Loy B and Wells O 1990 Effect ofIRT mulches on soil temperature early vegetative development in muskmelon and weed growth National Agricultural Plastics Congress Vol 22 pp 19-27
Maiers RP 1997 The Development ofEfficient Dryland Systems for Establishment of Windbreaks in Aird and Semi-Arid regions Thesis New Mexico State University Las Cruces NM
64
MaiersRP Harrington JT and Fisher JT 1997 Container stock type and site preparation effects on establishments of eldarica pine and Arizona cypress in arid and semi-arid plantings In fifth international conference on desert development Texas Tech University Lubbock TX August 12-17 1996 (In Press)
Maurer F and B Frey 1991 Benefits of wavelength-selective mulch Amer Veg Grower 3965-66
Mbagwu JSC 1991 Influence ofdifferent mulch materials on soil temperature soil water content and yield of three cassava cultivars J Sci Food Agric pp 569-577
McClain KM and Lavender DP 1989 Tissue water relations and survival of conditioned conifer seedlings during drought stress In proceedings of the Tenth North American Forest Biology Workshop July 1988 Vancouver BC pp 177-185
McDonald PM Fiddler GO and Harrison HR 1994 Mulching to regenerate a harsh site effect on Douglas-fir seedlings forbs grasses and ferns Res Paper PSW-RP-222 Albany CA Pacific Southwest Research Station Forest Service US Department ofAgriculture 10 p
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Nierenberg WA 1995 Encyclopedia of Environmental Biology Vol 1 New York Academic Press463-465
Parfett RI Stinchcombe GR and Stott KG 1980 The establishment and growth ofwindbreak trees in polyethylene mulch straw mulch and herbicide maintained bare soil In Proc 1980 British Crop Protection Conference Pp 739 -746
Patterson MG Wehtje G and Goff WD 1990 Effects ofweed control and irrigation on the growth of young pecans Weed Technology Vol 4 pp892-894
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Rasmussen D middot1990 No Need for Renovation-Management is the Answer A Windbreak Renovation Workshop October 1990 Hutchinson Kansas pp 42-50
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Splittstoesser WE and Brown JE 1991 Current Changes in Plasticulture for Crop Production Department ofHorticulture University of Illinois Urbana and Department ofHorticulture Auburn University Alabama
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Tidestrom I and Kittel SJ 1941 A Flora of Arizona and New Mexico The Catholic University of America Press Wasa NC
Tindall JA Beverly RB and Radcliffe DE 1991 Mulch effect on soil properties and tomato growth using micro-irrigation Agron J Vol 83 pp 1028-1034
Tivy J 1990 Agricultural Ecology Longman Scientific amp Technical London pp 99-102
Tonn JR and Graham RT 1982 The effect of brush competition and plastic mulch on moisture stress of planted Douglas-fir USDA For Ser Res Note INT-230 3pp
66
Traux B and Gagnon D 1993 Effects of straw and black plastic mulching on the initial growth and nutrition of butternut white ash and bur oak Forest Ecology and Management 57 17 - 27
Trinka DL and Pritts MP 1992 Micropropagated raspberry plant establishment responds to weed control practice row cover use and fertilizer placement J Amer Soc Hort Sci 117(6) pp 874-880
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Van Sambeek JW Preece JE Huetteman CA and Roth PL 1995 Use of plastic films for weed control during field establishment ofmicropropagated hardwoods 10th Central Hardwood Forest Conference pp496-506
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67
APPENDIX A PRESSURE POTENTIAL EQUATION
a
Where
H = pressure head in Mpa
as = saturated moisture content
a= -moisture content
m = I-lin
n = fitting parameter
tX = air entry potential
Block parameters for pressure potential equation
Block as a m n tX 1 0350 0148 0237 1306 16319 2 0330 0156 0242 1320 9918 3 0274 0120 0228 1295 15000
68
1 1 [(0350)om -1]13ii
Block 1 H= 0148 16319
l 1 [( 0330) 0242 -1] 1320
H- 0156Block 2 9918
1 1
[( 0274) 0228 -1] 1295
H= 0120Block 3 15000