Inspector Training – Basic Crop
Soils Review
Ver. 0711
IOIA Pre -Course
Objectives
Soils Training
Review
At the completion of the module,
participants will have:
Understanding Soil Health,
Soil Tests, Crop Fertility Inputs and
Organic Fertility Management
• a basic understanding of the soil
ecosystem
• be able to recognize the key
components of crop management
that effect soil quality and health.
Compiled by Steve Diver,
Agriculture Specialist, Fayetteville, AR
For the Independent Organic Inspectors Association
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Review ?’s
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What is Soil Health?
What was the % sand, silt and clay for the loam soil?
What is the difference between soil texture and soil structure?
What can you observe about texture and structure as an inspector?
What is the optimum pH range for Phosphate availability?
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List three trace elements.
Which will have a higher CEC – sand or clay?
What is an example of a microflora? – an example of mesofauna?
What is the Rhizosphere? What is a mycorrhizal fungi?
What are the three pools of Soil Organic Matter (SOM)?
Give a specific crop example for each of
– Soil depleting, Soil Neutral and Soil building.
What does C:N mean and what is a “good” number for compost?
What is a high rate of compost application?
What is “good” ratio for Ca:Mg? (based on Albrecht’s Theory)
What is Sul-po-mag?
Cont’d
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Soil Health is the fitness or capacity of soils
to support crop growth and maintain
environmental quality.
Physical
Chemical
Biological
Soil Quality
emerges from a ..
….. balance between
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the three soil components.
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Soil Texture Triangle
Sand - 0.05
What is the % mixture
of a loam soil at this
location?
Silt - 0.002
Soil texture
2.0mm
0.05 mm
relates to the size of the individual
particles
Clay - < 0.002 mm
Soil structure
refers to the clumping together or
“aggregation”
of sand, silt, and clay particles
into larger, secondary clusters.
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Inspector Training – Basic Crop
Soils Review
Ver. 0711
pH level
Effect of
soil pH
Texture and Structure
• Texture is related to mineral components
of the soil and does not change, but
on
plant nutrient
• Soil structure can be improved or destroyed
by choice and timing of farm practices.
availability
high
low
What can you observe as an inspector?
width of the bar
indicates availability
Graphic: www.ca.uky.edu/agc/pubs/agr/agr19/fff00009.gif
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Essential Elements for Plant Growth
Table of Cation Exchange Capacities
Don Schriefer - Agriculture in Transition
Major elements (required in large quantities)
Nitrogen (N)
Phosphorus (P)
Potassium (K)
Carbon (C)
Oxygen (O)
Sand + 2 -3 CEC
Secondary elements
(intermediate requirement)
Calcium (Ca)
Magnesium (Mg)
Sulfur (S)
Trace elements
Silt = 5 - 7 CEC
Clay = up to 60 CEC
(needed in very small amounts)
Copper (Cu)
Zinc (Zn)
Molybdenum (Mb)
Chlorine (Cl)
Iron
(Fe)
Boron (B)
Manganese (Mn)
Nickel (Ni)
Humus = 250 CEC
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The Root-Soil interface
Soil Biota
Classification
Body Width
Examples
Microflora
< 10 µm
Microfauna
<100 µm
Mesofauna
100 µm to 2 mm
Macrofauna
2 mm to 20 mm
bacteria
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fungi
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actinomycete
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algae
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protozoa
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nematode
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m i tes
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springtails
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earthworms
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millipedes
??
The Rhizosphere
The 3-dimensional zone at the interface between plant
roots and bulk soil
Mycorrhizal fungi live in symbiotic association with
plant roots and obtain nutrients from several
centimeters or even several meters further out into the
bulk soil, thus extending the mycorrhizosphere .
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Inspector Training – Basic Crop
Soils Review
Ver. 0711
Soil Organic Matter (SOM) is part of each
component and binds and weaves them
together.
Pools of Soil Organic Matter
Active or Labile SOM
— fresh OM (litter, manure), living organisms,
microbial biomass, partially stabilized OM;
half-life in days to a few years
Physical
Chemical
Slow or Intermediate SOM
— stabilized OM derived from above;
half-life of a few years to decades
Passive or Stable or Recalcitrant SOM
Biological
Organic Matter
— extremely recalcitrant molecules, humus;
half- life of decades to centuries
… the binding thread
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Crop Rotation:
C:N – Carbon:Nitrogen Ratio
of Organic Materials
What does the inspector do?
• Is the grower following their plan?
Material
• Is the same crop being repeated?
Seaweed
Poultry Manure
Dairy Manure
Fall Leaves
Legume Hay
Corn Stalks
Grass Hay
Sawdust
20 (e.g., 20:1)
5-15
5-25
30-80
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60
80
200-700
Compost
10-30
• Is there a balance ofSoil building crops
Soil depleting crops
Soil neutral crops?
• Do you see signs of the past year’s rotation
(crop residues, etc)
Carbon to Nitrogen
Optimum OM digestion
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10-30
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The Albrecht Ratios
Compost Rate of Application
Mg++: 10-20%
H+: 10-15%
Low
2-3 tons per acre
K +: 2 -5%
Na+: 0.5-2%
Regular
5 tons per acre
Ca ++: 60-70%
High
10-20 tons per acre
Base Cation Saturation Ratio
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Inspector Training – Basic Crop
Soils Review
Ver. 0711
Review
Rock Minerals
Evaluating Soil Fertility and Quality
during a Farm Inspection
examples of products used as soil amendments
and fertilizer inputs
Rock phosphate
Greensand
Sul-po-mag (K-Mag)
Gypsum
Limestone
Granite meal
Oyster shell
Rock dusts
Landscape Overview - including fence rows
Crop Rotation - simple or complex
Soil Texture and Structure
Crop and Weed species - patterns
Nutrient Deficiency
Soil Test results
Biological activity
Granular humates
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Soil Conditions and Associated “Weeds ” - based on Hill and Ramsay and Pfeiffer
Fertile cultivated soils
- Lambs quarters
- Chickweed
- Pigweed
- Chickory
Low Fertility
- Wild Carrot
- Mullein
- Wild Parsnip
- Ox-eye daisy
Potassium Levels
- high levels – Red clover, Wormwood, (clay soils)
- low levels - Yarrow (sandy /loam soils)
- unavailable K - Ragweed (wet loam/clay soils)
Alkaline Soils
- Bladder Campion
- Mustards
- Wild Carrot
- Sow Thistle
Acid Soils
- Sorrel
- Horsetail
-Docks
- Hawkweed
Hard pan and/or Crust
- Quack grass(fertile)
- Chamomille
- Mustard
- Bindweed (sandy)
Clay/Heavy, wet
- Buttercup
- Sow thistle
- Coltsfoot
- Canada Thistle
Sandy Soils
- White Cockle
- Horsetail
- Goldenrod
- Toadflax
Biological
Plant roots
Soil fauna
Mycorrhizae
Microbes
Texture
Humus
Structure
pH
Nutrients
Anions/Cations
Tilth
Drainage
Physical
The Soil
Ecosystem
Colloids
Aeration
CEC
Chemical
? Management Practices ?
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Resources on Soil
Biology & Microbial
Ecology
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Soil Biology Primer ?’s
Soil Food Web - what’s missing?
p. 5 – no earthworms
• Life in the Soil video
• Soil Biology Primer
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Where do red wigglers fit in? (Tropical earthworm in vermiculture)
p 42 – earthworms – generalist function as raw organic matter shredders.
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What causes the “Good Earth Smell”?
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How do nitrogen fixing bacteria operate?
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How can protozoa feed a crop with high N requirements?
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What group of organisms plays a significant role in P nutrition?
p. 19 – Actinomycetes
p. 19 – form symbiotic associations with the roots of legumes. ……
p. 26, 27 protozoa eat bacteria and release available N for plants
(based on different C:N)
p. 25 – mycorrhizal fungi
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How can nematodes be both beneficial and pathogenic?
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What is a more proper name for soil “Bugs”?
p. 30 -some species are beneficial and help to control of disease
and cycle nutrients - some are detrimental root feeding plant parasites
p. 34 Arthropods – (they have jointed legs )
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