2013 Master Gardener Trainee Soils Class JOHN ALLISON Charles City New Kent Agricultural and Natural...
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Transcript of 2013 Master Gardener Trainee Soils Class JOHN ALLISON Charles City New Kent Agricultural and Natural...
2013
Master Gardener Trainee
Soils Class
JOHN ALLISONCharles CityNew KentAgricultural and Natural Resources Extension Agent
Who is Virginia Cooperative Extension
Network of experts
and educators who provide information, education, and tools the public can use every day to improve life.
What Virginia Cooperative Extension Does
Brings the
research and resources of Virginia's land-grant universities, Virginia Tech and Virginia State to the public.
ANR Program Area Help sustain the profitability of
agricultural and forestry production by bringing current technology and management practices to the agriculture industry.
Enhance and protect the quality of our land and water resources.
Diagnose soil and crop problems for growers.
Help home owners answer lawn, garden, and landscape questions.
Connect the public with VT and VSU research.
What I Do
SoilsINFILTRATIONPERCOLATION
DOMESTICand
WILD
ATMOSPHERICHUMAN
FORESTPRAIRIEFARMS
SUBURBAN
Soils
Soils vary greatly across landscapes by Physical
Properties such as:
• Organic Matter Content• Color• Density• Texture
• Structure• Depth• Drainage • Porosity
Chemical Properties such as: pH and Nutrient Availability
Soil Physical Properties
Soil Physical Properties
OM mostly in surface horizon
50 percent solids
50 percent pore space
Soil Density
Particle Density – The density of each sand, silt, and clay particle.
Bulk Density – The density of the volume containing sand, silt, and clay particles.
PARTICLE DENSITY
100 % SOLIDS
WEIGHT 2.65 GRAMS
VOLUME 1cm3
BULK DENSITY
50 % SOLIDS, 50 % PORES
WEIGHT 1.5 GRAMS
VOLUME 1cm3
Soil Texture
Solids Made up of sand,
silt, and clay. The mixture of these
components is called Soil Texture.
Soil Texture
Textural Triangle
Soil Texture
Soil Ribbons
Soil Structure
Solids Made up of sand,
silt, and clay. The orientation of
these components is called Soil Structure.
Granular Structure Prismatic Structure
Blocky StructurePlaty Structure
Columnar Structure
Soil Porosity
SOIL PORES are the spaces between soil structural units. They are also made by roots, burrowing insects and animals. They are inhabited by microorganisms and roots. They contain water and air. Their volume is
determined by texture, structure, and bulk density.
Soil Water
SATURATION All pores are filled with
water. All air is excluded. Anerobic conditions
exist. Plants and animals
suffocate. Microbes reduce iron
oxides to obtain oxygen.
Soil Water
FIELD CAPACITY Two thirds of the
pores are filled with water.
Air in one third of pores.
Areobic conditions exist.
Plants, animals, and microbes thrive.
Soil Water
AVAILABLE WATER Water content
between Field Capacity and Wilting Point.
Two thirds to one third of the pores are filled with water.
Soil Water
WILTING POINT Less than one third
of pores filled with water.
Water is adsorbed too tightly to soil particles to be available to plants.
Plants, animals, and microbes die.
Soil Color Iron Oxides coat
every soil particle. Where Organic
Matter does not mask the rust, soils exhibit rusty colors.
Saturated conditions cause microbes to use oxygen from the oxide compounds leaving the Iron soluble in soil water.
RUSTY IRON
Soil Color
REDYELLOW
Soil Color
BROWN GRAY
Organic Matter
PARENT MATERIAL
Actinomycetes are bacteria critical in decomposition of organic matter and humus formation. Their presence is responsible for the sweet "earthy" aroma associated with a good healthy soil.
ActinomycetesMycorrhizaBacteriaFungi
Organic Matter
Symbiotic association between a fungus (Myco) and the roots (rhiza) of the plants.
The plant gains increased exploration of the soil (rhizo sphere) with the intricate net of hyphae that increases the uptake of water and nutrients from the soil.
The fungus uses the carbon provided by the plant for its physiological functions, growth and development.
Mycorrhiza
Organic Matter
Soils with sufficient OM typically have an increased capacityto hold water, requireless fertilizer, and
havehigher yields than
soilsWith little or no OM.
Organic Matter
Soil Horizonation
Soil Horizonation
O Horizon
A Horizon
E Horizon
B Horizon
C Horizon
R Horizon
Soil Horizonation
A Horizon: Top Soil; Zone of Organic Matter accumulation; Horizon with the most biological activity.
B Horizon: Subsoil; Zone of clay accumulation; Horizon with the most water holding capacity.
Soil Horizonation C Horizon is the Parent Material, not soil. PARENT MATERIAL is the geologic material that
soil develops from. It may be:rock that has decomposed in place.sand, silt, and/or clay that has been
deposited by wind, water, or ice. The character and chemical composition of the
parent material plays an important role in determining soil properties.
Soil Horizonation
Horizons are defined by physical and chemical parameters such as:
• Acidity• Nutrient Availability• Organic Matter
Content• Texture• Structure • Density• Porosity• Color• Mineral Content• Drainage
Soil Drainage
Excessively Drained Well Drained Moderately Well Drained Somewhat Poorly Drained Poorly Drained
Soil Drainage
Excessively Drained
Sandy throughout,droughty.
Soil Drainage
Well Drained
No water tablein the root zone.
Soil DrainageModerately Well Drained
Any texture; soil profilehas a well drainedhorizon immediatelybelow the top soilfollowed by a horizonaffected by a SHWT dominated by brightcolors.
Soil Drainage
Somewhat Poorly Drained
Any texture; soil profile hasa horizon affected by aSHWT immediately beneaththe A that is dominated bybright colors, immediatelyfollowed by a horizon affected by a SHWT and dominated by gray colors.
Soil Drainage
Poorly Drained
Any texture; soilprofile is
affectedby a SHWTthroughout. Soilis dominated bygray colors.
Soil Depth
Very Shallow Shallow Moderately Deep Deep Very Deep
Soil Depth
VERY SHALLOW SOILS
10 inches
7 inches
Soil profile thickness is
10 inches or less above the Parent Material.
Soil Depth
14 inches
16 inches
Soil profile thickness
is 10 to 20 inches over Parent Material.
SHALLOW SOILS
Soil Depth
36 inches
24 inches
MODERATELY DEEP SOILS
Soil profile Thickness is
20 to 40 inches over Parent Material.
Soil Depth
44 inches55 inches
DEEP SOILS
Soil profile thickness is 40 to 60 inches over Parent Material.
45 inches
Soil Depth
VERY DEEP SOILS
Soil profile thickness is
greater than 60 inches over Parent Material.
Soil FormationFive Soil Forming Factors
Soil Formation
CLIMATEFreeze - ThawWetting -
Drying
Soil Formation
ORGANISMS
Soil Formation RELIEF
Soil Formation
PARENT MATERIAL
River Deposits
Residual Weathering
CoastalPlain
Sediments
Soil Formation
TIME
Soil Erosion
WIND EROSION WATER EROSION
SALTATION LIQUID SUSPENSION
Soil Erosion
Erosion Controls prevent and/or reduce soil erosion.
Soil Erosion
Sediment Control captures
and contains eroded soil.
Soil ErosionSuburban Soil Erosion and Sediment Control
Practices
HydroSeeding
Rock Dam
Straw Wattles
Sediment Fence
Soil ErosionAgricultural Soil Erosion and Sediment Control
Practices
Cattle Exclusion
Cover Crops No-Till
Strip Cropping
Soil Fertility and FertilizersSoil Supplied Nutrients
Macronutrients: P, K, S, Ca, Mg Micronutrients: B, S, Fe, Cu, Cl, Mn, Mo, Zn
Atmosphere Supplied NutrientsMacronutrients: C, H, O, N
Mos
t P
rod
uct
ive
Soi
ls
Bas
icit
yA
cid
ity
Strong
Medium
Slight
Slight
Moderate
Medium
Strong
Very Strong
9.0
8.0
7.0
6.0
5.0
4.0
Neutrality
pH value defines activity of Hydrogen cation
pH = - log[H+]
Soil pH
pH and Fertilizer Use
Soil acidity can be directly toxic to plants but more often it reduces the ability of the plant to take up nutrients.
pH Importance
Low pH = Mo Deficiency
High pH = Mn Deficiency
Types of Soil Acidity
Exchangeable or Reserve Acidity
Active Acidity• H+ cation in soil solution measured as pH.
• Very small amount of Total Acidity.
• Acidity that affects plant growth.
• Various Al compounds react with water resulting in free
H+ cations in solution.
• 1,000 to 100,000 times greater than active acidity.
Liming the Soil
Water pH = Active pH
Buffer pH • Used for lime recommendations
• Measures Active and Reserve Acidity (Total Acidity)
How Lime WorksA Ca2+ ion from the lime replaces two H+
ions on the cation exchange complex.
The H+ ions combine with OH- to form water.
Soil pH increases because the acidity source (H+) has been
reduced.
How Lime Works
Ca2+ clay- - -
--
-H+
H+
clay---
- ----
---
CaCO3 (Lime)
+ H2O + CO2
Water Carbon Dioxide
Ca++ + HCO3- + OH-
+
Lime 2 to 6 months ahead of planting to allow sufficient time for soil reaction to take place.
Particle Size and Chemical Composition of Liming Materials
PARTICLE SIZE or mesh influences the speed at which the material dissolves and reacts with the Hydrogen ion in solution.
CHEMICAL COMPOSITION determines a liming material’s acid-neutralizing value.
Pure calcium carbonate, CaCO3, is the standard for all liming materials and has an acid neutralizing value
of 100 percent. When a liming material is
evaluated, it is compared to calcium carbonate, and its neutralizing value is called the Calcium Carbonate Equivalent, CCE.
200 mesh
20 mesh
10 mesh
100 mesh
1/8 inch
3/16 inch
1/4 inch
1/2 inch
3/4 inch
IPNI
How Quickly Lime Works
Lime Application• Lime recommendation should last two to three years. After that retest the soil.
• A liming material with a higher CCE value will have a greater effectiveness than one with a lower CCE value.
• Lime can be applied any time of
the year, but late summer and fall applications are preferred.
Fertilizers
Liebig’s Law of the Minimum
Fertilize to prevent yield loss.
Focus $ on correct nutrient.
Do not over-apply• Agronomic• Environmental• Waste Money
Lab Test ResultsShows the relative availability of nutrientsas a rating:
• L=Low - Plants almost always respond to fertilizer. • M=Medium - Plants sometimes respond to fertilizer. A moderate amount of fertilizer is typically recommended to maintain fertility.• H=High to VH=Very High - Plants usually do
not respond to fertilizer.
Fertilizer Recommendations
• Fertilizer recommendations may be used for the same
crop for two to three years then retest the soil.
• When soil tests are High or Very High, retest the following year to determine if fertilizer will be needed.
Fertilizer Recommendations
No soil test is performed for nitrogen because this element is too mobile in the soil for laboratory results to be useful.
Nitrogen fertilizer recommendations are based on the crop/plant to be grown, the previous crop, and yield potential.
Fertilizer Analysis
Complete AnalysisFirst Number:
20 percent Nitrogen (N)
Second Number:
10 percent Phosphorus (P)
Third Number:
20 percent Potassium (K)
Fertilizer AnalysisComplete Analysis
A 50 Pound Bag Would Be:
First Number:
10 pounds Nitrogen (N)
Second Number:
5 pounds Phosphorus (P)
Third Number:
10 pounds Potassium (K)
Fertilizer AnalysisIncomplete Analysis
A 50 Pound Bag Would Be:
First Number:
9 pounds Nitrogen (N)
Second Number:
23 pounds Phosphorus (P)
Third Number:
0 pounds Potassium (K)
Slow-Release Fertilizer (N)Beneath the guaranteed analysis one can find a statement to the effect that X percent of the nitrogen (expressed as a percentage by weight of the package contents) is in slow-release form. The words water insoluble, slowly available or slowly available soluble nitrogen also indicate slow-release sources of nitrogen.
If, for example if a 50 pound bag of 10-10-10 fertilizer
says it contains 5 percent slow-release nitrogen, divide
the 5 percent by the total percent N in the product and
multiply by 100 to get the percentage of nitrogen that
is in slow-release form. In this example it is 5/50 x 100 = 50 percent.
Organic Fertilizers
Cottonseed Meal Blood Meal Bone Meal Manure Bio-Solids
Cottonseed meal is the byproduct remaining after cotton is ginned and the
seeds crushed and the oil extracted.
Organic Fertilizers
Cottonseed Meal Blood Meal Bone Meal Manure Bio-Solids
Blood meal is a dry, inert powder made from blood used as a high-nitrogen fertilizer.
Organic Fertilizers
Cottonseed Meal Blood Meal Bone Meal Manure Bio-Solids
Bone meal is a mixture of finely and coarsely ground animal bones and slaughter-house waste
products. It is a slow-release phosphorus fertilizer.
Organic Fertilizers
Cottonseed Meal Blood Meal Bone Meal Manure Bio-Solids
Common forms of animal manure include dry farmyard manure and liquid farm slurry. Manure may contain plant material such as straw used as bedding for animals to absorb feces and urine.
Organic Fertilizers
Cottonseed Meal Blood Meal Bone Meal Manure Bio-Solids
Green Manures are crops grown for the express purpose of plowing them in, thus increasing fertility through the incorporation of nutrients and organic matter into the soil. Legumes such as clover are often used for this, as they fix nitrogen.
Organic Fertilizers
Cottonseed Meal Blood Meal Bone Meal Manure Bio-Solids
Since the 1920s, the City of Milwaukee Sewerage Commission has been converting Biosolids into Milorganite, a heat-treated, pelletized, organic fertilizer made from processed wastewater municipal treatment plant organic waste.
Nutrient Summary
General Rule of Thumb
N is for leafy top growth. P is for root and fruit production K is for cold hardiness and disease resistance
Soil Sampling
Divide the landscape into areas of unique
use.Examples are
vegetablegardens, lawns, flower beds, and areas wherelandscape plants are growing. Sample and box the soil from each area separately.
Soil Sampling
To collect soil samplesuse a clean stainless steel or chrome platedsoil probe, hand
garden trowel, shovel or
spade.
Soil Sampling Make up the composite
soil sample by taking 10 or more sub-samples from different locations within each area. Use a zigzag pattern to capture the variability of the area. Mix soil samples in a clean plastic bucket and place in a box to be sent to the VT soils testing lab.
Virginia TechSoil Testing Lab 45 Smyth Hall Blacksburg, VA 24061
At The LabSoil Extracts Measure:
• What is considered “plant available”.• DOES NOT extract total nutrients• Based on calibration curves from many years of
research• Each soil test is different and must be compared
to the correct recommendations curves.
• For Instance: You cannot use a Mehlich-1 curve
for Mehlich-3 extract data.
Acknowledgements
Dr. Mark S. ReiterSoils and Nutrient Management SpecialistEastern Shore AREC
Contact InformationJohn AllisonANR Extension Agent
10900 Courthouse Road 11809 New Kent HighwaySuite 240 Suite 1P.O. Box 55 P.O. Box 205 Charles City, VA 23030 New Kent, VA [email protected] [email protected] Office: (804) 652-4743 Main Office: 804-966-9645 Fax: (804) 829-9820 Fax: 804-966-5013