· 2017. 1. 19. · nature’s way of adding diversity to a system which lacks diversity. ADEQUATE...
Transcript of · 2017. 1. 19. · nature’s way of adding diversity to a system which lacks diversity. ADEQUATE...
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IMPORTANT FACTORS
• SHORT-TERM STUDIES ARE NOT ACCURATE IN EVALUATING TREATMENTS SUCH AS TILLAGE OR ROTATIONS WHICH HAVE LONG-TERM IMPACTS.
A FARMER MANAGES
ECOSYSTEMS AND TAKES
SUNLIGHT, WATER, AND
CARBON DIOXIDE AND MAKES
THEM INTO PRODUCTS TO BE
SOLD.
ECOSYSTEM PROCESSES
• WATER CYCLE
• ENERGY FLOW
• MINERAL CYCLE
• COMMUNITY DYNAMICS
Wheat Health ManagementCook and Veseth
Crop rotation allows time for natural
enemies to destroy the pathogens of one
crop while……unrelated crops are grown.
SEQUENCE IS
ONLY ONE
COMPONENT OF A
ROTATION
• Proper Intensity
• Adequate Diversity
• Stable/Sustainable Profitability
Crop Rotations
PROPER INTENSITY
Native vegetation is the
best indicator of the range
of intensities which are
appropriate for a location.
PROPER INTENSITY
Most of the plant growth problems
blamed on no-till are the result of
inadequate diversity or improper
intensity.
PROPER INTENSITY
• Put water saved by no-till to work
• More high water-use crops and Cover Crops or Double Crops
• Proper intensity reduces risk
– Plant growth, nutrients, etc.
WEB SOIL SURVEY
ECOSYSTEM PROCESSES
• MINERAL CYCLE-Are the
nutrients available for plant use and
environmental services”? Or have
they been leached, eroded, or
transported from the landscape?
ECOSYSTEM PROCESSES
• MINERAL CYCLE-
–Ecosystems that leak nutrients become
deserts.
–Saline seeps indicate leakage
–Decreasing pH indicates leakage
–One unit train of soybeans contains
almost 1/2 million pounds of phosphorus
Saline Seep Formation
COVER and FORAGE CROPS
Cover and forage crops provide the opportunity to increase both intensity and diversity in situations where production of a grain crop would not be possible, would be unprofitable, or would be excessively risky.
COVER CROPS
In humid environments (tall-grass prairie or wetter) the goal should be to have something growing at all times. In areas with a limited growing season this will require the use of cover crops and/or forage double crops.
COVER CROPS
In subhumid, semiarid, and arid environments cover crops can be utilized to increase organic matter and biological activity and often as a valuable source of forage.
CATCH AND
RELEASE
NUTRIENTS
Irrigated Corn By Previous Crop
Wheat-Wheat-C-C-SB-SB rotation
2009 Dakota Lakes Res. Farm
Rotation N rate 0 lb
Yield
Bu/ac
N rate 36
Yield
Bu/ac
N rate 72
Yield
Bu/ac
N rate 108
Yield
Bu/ac
CC – lentil,
CVetch, turnip
176.0 236.1 214.0 233.9
Nitrogen rate impact on yields
STN = 108 lbs/ac Yield goal = 220 bu/ac
COVER CROPS
If you get stranded in a rain on the back 40, do you drive home across the tilled field or the pasture?
ADEQUATE DIVERSITY
Weeds and diseases are
nature’s way of adding
diversity to a system which
lacks diversity.
ADEQUATE DIVERSITY
Nature’s efforts to add
diversity can be countered
by adding beneficial
diversity to the system.
ADEQUATE DIVERSITY
AT LEAST THREE CROP TYPES.
LONG INTERVALS OF 2 TO 4
YEARS ARE NEEDED TO BREAK
SOME DISEASE AND WEED
CYCLES.
ROTATION IMPACT ON W.WHEAT15 ROTATION STUDY LYMAN COUNTY, SD
1995, 1997, 1998, 1999, and 2000
Interval Between Wheat
Yield
Alternate Year Wheat-XXX
46.8
Two Years Out Wheat-Corn-XXX
53.0
Two In – Two Out SW-WW-Corn-XXX
48.4
Three Years Out WW-Corn-SB-Pea
57.9
Rotation Impact on W.Wheat
Cost/Unit of Production
1994-1995 & 1997-1999
Lyman County
Rotation Cost in $/bu.
WW-Fallow $4.60
WW-Corn-Fallow $3.79
WW-Corn-Pea $2.45
SW-WW-Corn-SB $2.64
Impact of Rotation & Low Disturbance
On Weed Populations
Weed of Interest: Waterhemp
Number of Weeds Previous:10
Number of Seeds Per Weed:100
Rotation Interval Vs. Weeds
-2.0E+06
0.0E+00
2.0E+06
4.0E+06
6.0E+06
8.0E+06
1.0E+07
1 3 5 7 9 11 13 15 17
Years
Weed
s In
Mil
lio
ns
1 Year Out
2 Years Out
2 In - 2 Out
Natural Control Benefit
Cool-Season Weeds (such as Downy Brome)
2 Years of Warm-Season Crops (or Fallow)
Reduce Number of Seeds > 95%
Same with
Warm-Season Weeds Cool-Season Crops
(W-C-F)
Weed Life Cycle Green Foxtail
Ap May June July Aug Sep Oct
Corn P
W. Wheat
Foxtail ------ ( E ) ------ ** ( F ) **
Weed Life Cycle
Ap May June July Aug Sep Oct
Corn P
W. Wheat X X X
Foxtail ------ ( E ) ------ ** ( F ) **
Green Foxtail
Does it Work ? (Field Trial)
Long-Term Rotation Study
Cool and Warm Season Crops
No-Till : Herbicides - Weed Control
Weed Density After 12 Years
(No Herbicides – Number of Weeds / m2)
94
40
7
0
25
50
75
100
W-CP W-C-CP Pea-W-C-SB
Weeds
(plts/m2)
Rotation Design < - > Weeds
Tillage – Seed Survival
Green Foxtail
Seed Placed at 3 Depths in Soil
0, 2, and 4 inches
Measure Number of Live Seed Yearly
Green Foxtail Survival in Soil
After 2 Years
11
28
55
0
20
40
60
0 2 4
Depth in Soil (inches)
Live Seed (%)
Tillage - Weed Seedling Emergence
Weed Seed Shed: (once)
No-Till
Till (seed 1 – 3 inches deep)
Count Seedlings Yearly, for 3 Years
Several Species, Average of 4 Sites
10088
48
32 33 4
0
25
50
75
100
1 2 3
Seedlings Within a Year
Seedlings (%) Till No-Till
Seedling Emergence - Tillage
10088
48
32 33 4
0
25
50
75
100
1 2 3
Seedlings Within a Year
Seedlings (%)
Till No-Till
Corn Pea WW Corn
10088
48
32 33 4
0
25
50
75
100
1 2 3
Seedlings Within a Year
Seedlings (%)
Till No-Till
Corn Pea Corn
DIVERSITY IN CROP TYPE
•Diversity in seeding date.
•Diversity in rooting pattern.
•Diversity in root architecture.
•Diversity in residue type.
•Diversity in insect pests.
DIVERSITY IN CROP TYPE
•Diversity in weed suppression.
•Diversity in micro organisms.
•Diversity in harvest date.
•Diversity in beneficials.
•Diversity in ………MORE.
SIMPLE ROTATIONS
• Winter Wheat-Corn-Fallow
• Winter Wheat-Corn-Canola
• S. Wheat-W. Wheat-Corn-Sunflower
• Winter Wheat-Corn-Pea
• Corn-Soybean
SIMPLE ROTATIONS
Advantages
Simple-limited number of crops to manage
and market.
Disadvantages
Limited-all corn behind wheat or all winter
wheat into spring wheat.
Rotations With Perennial Sequences
• C-SB-C-SB-C-SB-Alf-Alf-Alf-Alf
• Many other examples
Rotations with Perennial Sequences
Advantages
Simple-limited number of annual crops to
manage and market.
Excellent place to spread manure.
Probably can produce more soil structure
than annual crops (grass or grass mixtures)
Biomass crops may hold potential
Rotations with Perennial Sequences
Disadvantages
Difficult to manage sufficient percentage of
land in a perennial crop without grazing.
(harvesting 40% of farm as forage is tough)
(using less perennial minimizes impact)
Marketing perennial crop is an issue.
COMPOUND ROTATIONS
Combination of two or more simple
rotations in sequence to create a longer
more diverse system.
EXAMPLE:
S. Wheat-W. Wheat-Corn-SB-Corn-SB
COMPOUND ROTATIONS
Advantages
Limited number of crops to manage.
Creates more than one sequence for some
crop types.
Disadvantages
Limited ability to spread workload.
COMPLEX ROTATIONS
Rotations where crops within the same crop
type vary.
EXAMPLE:
Barley-W.Wheat-Corn-Sunflower-Millet-
Pea
COMPLEX ROTATIONS
Advantages
Capable of creating a wide array of crop
type x sequence combinations.
Disadvantages
Requires substantial crop management
and marketing skill.
STACKED ROTATIONS
Rotations where crops or crops within the
same crop type are grown twice in
succession followed by a long break.
EXAMPLE:
Wheat-Wheat-Corn-Corn-Soybean-
Soybean
Stacked Rotation Concepts
• The goal is to allow sufficient time for
pest pressure to decline to very low
levels before sequencing the crop or
crop type 2 times.
Stacked Rotation Concepts
• Attempt to keep pest populations diverse (confused). Diversity in sequences and intervals used.
• Mix of long and short residual herbicide programs. Reduces costs and minimizes the chance of resistance and biotype changes.
• Two year break between corn and wheat
STACKED ROTATIONS
Advantages
May be capable of reducing the risk of
developing of biotype resistance.
Can reduce cost of herbicide programs.
Disadvantages
Not well tested.
Some crop sequences may not be ideal.
The goal is to be
INCONSISTENT
in both sequence and
interval
Rotations Utilizing Both Stacked
and Normal Sequences
• Canola-W.Wheat-Soybean-Corn-Corn
• S.Wheat-W.Wheat-Pea-Corn-Millet-
Sunflower.
• WW-WW-WW-WW-Sorg-Sorg-Sorg-
Sorg-SF-SF-SF
Dryland Rotations at DLRF
• W-W-Corn/Sorg-Corn-Broadleaf
• W.Wheat-W.Wheat-Broadleaf-Milo-
Corn-Pea/Canola/Flax
• WW-Corn-Pea
• WW-Soybean-Corn/Milo-Pea
Irrigated Rotations at DLRF
• Continuous Corn (With CC)
• Corn-Soybean (With CC)
• Corn-Corn-Pinto-WW/CC-Soybean/Pinto
• Wheat-Wheat (CC)-Corn-Corn-Pinto/SB
–Soybean/Pinto
The Rotation Must Fit the
Ecosystem and the Operator
• There is no set recipe or “best” rotation
• Individual fields may need differing treatment due to soils, location, proximity, history, landlord, ownership…….
• Understanding the power or rotations is the key.
Corn-Pea-WW
Sb-Corn-Pea-WW
Rotation Impact on W.Wheat
Dakota Lakes Research FarmRotation Yield Precip*
Corn-Pea-WW 2006 60 7.9
SB-Corn-Pea-WW 2006 29
Corn-Pea-WW 2005 92 23.7
Sb-Corn-Pea-WW 2005 57
Corn-Pea-WW 2002 56 6.4
SB-Corn-Pea-WW 2002 28
2013 Yield DataDakota Lakes Research Farm
• C – SB rotation (Cover Crops historically increases soybean yield 7.3 bu/a on average vs no CC in this rotation).
• Yield 2013: Soybean with WW CC 62.9 bu/a. We would have expected around 55.6 bu/a without CC.
2013 Yield DataDakota Lakes Research Farm
• C – C – SB – Wheat - SB rotation
• 1st year SB yield - NO cover crop = 76.3 bu/ac
• 2nd SB yield – Cover Crop = 81.2 bu/ac
2013 Yield DataDakota Lakes Research Farm
• Cover crop increased SB yield (7.3 bu/ac), but more importantly crop diversity increased SB yield by 15.9 bu/ac.
C – SB rotation = 62.9
C – C – SB – Wheat – SB = 78.8 bu/ac
• CONTINUOUS CORN• 203 bu/a
• CORN-SOYBEAN • 217 bu/a
• C-C-SB-W-SB• 235 Corn
DIVERSITY IMPACT
• CONTINUOUS CORN• 1,015,000 corn, 0 soybean, 0 wheat
• CORN-SOYBEAN • 542,500 Corn, 157,250, 0 Wheat
• C-C-SB-W-SB • 470,000 Corn, 157 ,600, 120,000 Wheat
DIVERSITY IMPACT IF 5,000 ACRES
• CONTINUOUS CORN• 1,015,000 corn, 0 soybean, 0 wheat
• CORN-SOYBEAN • 542,500 Corn, 157,250, 0 Wheat
• C-C-SB-W-SB • 470,000 Corn, 157 ,600, 120,000 Wheat
• Would you trade 72,500 bu of corn for 120,000 bu of wheat plus 350 bu of soybean? I would.
DIVERSITY IMPACT IF 5,000 ACRES
ORGANIC MATTER
MAKES A
DIFFERENCE.
“Within all textural groups, as organic
matter increased from 1 to 3%, the
available water capacity approximately
doubled. When organic matter content
increased to 4%, it then accounted for
more than 60% of total AWC“.8
When soil water storage capacity is low,
much of the rain that falls during extended
periods of precipitation is lost. In contrast, a
high water storage capacity, combined with
the effective capture of rain and snowmelt
over the fall, winter and spring can support
a crop through an extended dry period.
Commonality Among Tillage Tools
• All Tillage Tools Destroy Soil Structure.
• All tillage tools decrease water infiltration
• All tillage tools reduce organic matter
• All tillage tools increase weeds.
Tillage is to Agriculture what
Fracking is to Petroleum.
They both increase the speed and
extent of nutrient removal from a
resource-leaving the resource
degraded
Continuous Low-Disturbance No-
till in Combination with Diverse
Rotations and Cover Crops:
A BIOLOGIC ANSWER TO A
BIOLOGICAL PROBLEM
Looking
backward
Looking
forward
Le Caussanel, in the 70’s Le Caussanel, 2011
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