Organic soil building and how to convert a fertility recommendation from conventional to organic.

1. Building Soil Organically: A Discussion of
Practical Applications and Why They Work
Bo Holland
Screech Owl Farm
Nelson County, VA
Daniel Parson
Oxford College Farm
Oxford, GA

2. Approach to Production
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•
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Diverse vegetable operation
About 3 acres production
Intensive rotation in 12 quarter-acre blocks
Marketing-CSA, Farmers’ Market, Restaurant
sales

3. Organic Production
“A production system that is managed… to
respond to site-specific conditions by
integrating cultural, biological, and
mechanical practices that foster cycling
of resources, promote ecological
balance, and conserve biodiversity”

4. Organic Fertility
• Cultural: Rotation planning
• Mechanical: Mined substances
• Biological
– Cover cropping in rotations
– Plant and animal materials

5. Crop Rotations
• Prevent one crop from robbing nutrients
• Allow maximum use of cover crops
• Provide planning for fertility
– Crop list applies directly to land area
– You know what crop comes next
– Possible to schedule liming or compost/mulch
additions

6. 8
12
7
6
11
13
10
5
9
4
3
2
1

7. Field Rotation Plan 2013
Field
1
Crop
Rye Aisles
Potatoes
Sudex/Soybeans
Garlic
2
Late Squash and Beans
Wheat/Crimson Clover
3
Cabbage and Kale
Buckwheat
Cabbage and Kale
Rye and Clover
4
Peppers/Eggplant
Oats/Winter Peas
5
6
Beets
Soybeans/Buckwheat
Beets
Rye/Crimson Clover
Cucumbers/Squash
Oats/Winter Peas
7
8
Arugula and Lettuce
Soybeans/Buckwheat
Arugula and Lettuce
Rye/Clover
Sweet Potatoes and Okra
Rye and Clover
9
Early Beans, Basil, and Flowers
Rye/Hairy Vetch
10
Broccoli
Buckwheat
Broccoli
Rye and Clover
11
Melons and Winter Squash
Oats and Winter Peas
12
Tomatoes and Late Lettuce
Oats and Winter Peas
13
Carrots
Soybeans/Buckwheat
Carrots
Season
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall

9. Fertility Needs
N-P-K
Field Rotation Plan 2013
Field
1
Crop
Rye Aisles
Potatoes
Sudex/Soybeans
Garlic
2
Late Squash and Beans
Wheat/Crimson Clover
3
Cabbage and Kale
Buckwheat
Cabbage and Kale
Rye and Clover
4
Peppers/Eggplant
Oats/Winter Peas
5
6
Beets
Soybeans/Buckwheat
Beets
Rye/Crimson Clover
Cucumbers/Squash
Oats/Winter Peas
7
8
Arugula and Lettuce
Soybeans/Buckwheat
Arugula and Lettuce
Rye/Clover
Sweet Potatoes and Okra
Rye and Clover
9
Early Beans, Basil, and Flowers
Rye/Hairy Vetch
10
Broccoli
Buckwheat
Broccoli
Rye and Clover
11
Melons and Winter Squash
Oats and Winter Peas
12
Tomatoes and Late Lettuce
Oats and Winter Peas
13
Carrots
Soybeans/Buckwheat
Carrots
Season
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
100-100-150
100-75-100
100-50-100
100-50-100
100-100-150
75-0-75
75-0-75
100-50-100
100-50-100
100-50-100
100-50-100
60-60-60
100-100-100
100-100-100
80-100-150
80-150-200
80-0-75
80-0-75

10. Converting a Conventional
Recommendation to Organic
• UGA online resource
• Apply organic amendments for any
recommendation
• What is your preferred amendment?
– Least expensive
– Most effective
– Locally available
– On-farm resource like compost

11. Converting a Conventional
Recommendation to Organic
• Begin with your preferred amendment
-or• The most balanced in N P K
• Determine what else you need to apply
• Convert amendment pounds/acre to
pounds/field or pounds/bed

20. What Next?
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•
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Calculate application for each field
Chart the amounts for each amendment
Add up those amounts
Put together an order
– Plan ahead for when you need the materials
– Get together with others in your local area

22. Make it Practical
• Write down ‘recipe’ for each field
• Make copies and keep in the barn
• Convert to volume on fertilizing day
– Weigh amendments into bucket/container
– Mark bucket or container
– Use markings each time to get it right
• Load bags into cart and measure in field

24. Is it Effective?
• Previous ‘one-size-fits-all’ approach
– Wasting $ and resources?
– Optimal crop response?
• New system for 2013
– Spent the same $ on amendments
– Improved crop response
– Better use of resources

25. Building Soil Organically:
Practical Applications and Why they Work
Southern Sustainable Agriculture
Working Group Annual Conference
Mobile, AL – January 17, 2014
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26. Principle: Feed the Soil, and
Let the Soil Feed the Crop
• Soil life modulates the release
of plant-available nutrients.
• Its activity is intensified in the
plant rhizosphere (next to root
surfaces) to maximize efficient
nutrient delivery.
 Provided that the soil life
receives an adequate quantity
and diversity of organic
residues and plant root
exudates.
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27. Why it Works: Strengths of the Parson
Produce Cropping System
• 18 cover crops within a 13
year crop rotation.
• Most cover crops grown
to early flowering =
optimum stage for quality
and quantity of fresh OM.
• Organic fertilizers (feather
meal, True 7.5-5-7.5) also
feed soil life.
A vigorous cover crop of
buckwheat occupies a fallow
bed (foreground).
Production crops grow in
other beds (background).
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28. Why it Works:
some Enhancements to Consider
Add compost to the system:
 Provides diverse inoculum
of beneficial soil organisms.
 Good source of P –
calibrate rate to deliver
desired amount.
Shorten interval between
cover crop termination and
vegetable planting:
 Consider no-till or strip-till
planting into rolled cover.
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29. Principle: the Law of Return
Give back to the soil what has
been taken out through
production and cultivation.
(Sir Albert Howard, 1940s)
Nutrients: replenish
nutrients removed in harvest
Organic Matter: feed the soil
life – cover crops, manure,
organic mulch, residues, etc.
Harvest removes nutrients
and organic matter from
the cycle. Tillage burns
up OM, promotes leaching.
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30. Why it Works: Strengths of the System
• Science-based translation of
Clemson U. recommendations
for organic fertilizer use.
• Clemson U. rates for N and K
are conservative, and thus
sufficient.
• Crop- and field-specific NPK
rates optimize outcomes.
• Slow-release organic fertilizers
can be applied pre-plant – no
side-dress needed.
Tomatoes may require
more K and less N than
leafy greens, and are
amended accordingly.
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31. Why it Works:
some Enhancements to Consider
Nitrogen recommendations
ignore soil mineralization and
cover crops:
 Can reduce N inputs by 0.5X
the total cover crop N.
 Healthy, living soil can
provide most or all of a warm
season crop’s N needs.
 Cool season crops need
additional N – succulent
green manures or organic
fertilizer.
Legume or legume-grass
cover crops can provide
35-100 lb available N/ac.31

32. Clemson U. recommendations
for P exceed crop P removal
even where P tests sufficient.
 Vegetable harvests remove
20 – 60 lb phosphate/ac.
 Reduce phosphate
application to this range
except where soil P is
below sufficiency.
 Very high soil P inhibits
mycorrhzal fungi – apply
less P for net drawdown.
Yield
Why it Works:
some Enhancements to Consider
Phosphorus application rate
In low-OM, low-biological
activity soil, much of applied
P is tied up, and rates higher
than actual crop uptake are
needed for optimum economic
yield. In healthy, living soil,
mycorrhizae and other soil
life make more P crop-available.
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33. A couple concerns with the Clemson
recommendations
• Micronutrient recommendations based on
crop only, without reference to soil test level:
– Manganese recommended for snap bean (“Mnsensitive crop”) where soil Mn level is ample.
– No Mn is needed in this case.
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34. Four Principles of Soil Health
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Keep soil covered as much of year as possible.
Maximize living roots in the soil profile.
Minimize soil disturbance.
Energize the soil system with biodiversity.
– Multi-species cover crops - 5 or more species from
3 or more plant families
Based on the work of the NRCS Soil Health Team in Greensboro,
NC – David Lamm, Ray Archuleta, Steve Woodruff, and Terry
Briscoe
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35. Why it Works: Strengths of the System
- maximizing soil coverage, living roots
• Tight Rotation – 18
cover and 18 cash
crops in 13 years
• No unplanted fallow
• Living vegetation
present most of the
year
• Cover crops provide
abundant root
exudates for soil life
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36. Why it Works: Strengths of the System
- minimizing soil disturbance
• No chemical pesticides,
herbicides, fungicides –
protects soil life.
• Limited use of soluble
fertilizer (potassium
sulfate only).
• Minimal, shallow tillage
to plant cover crops
after vegetable harvest.
Cover crops, cash crops, and
even weeds are far better for
the soil than herbicide-fallow.
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37. Why it Works: some Enhancements to
increase cover & roots, reduce disturbance
Pepper starts are no-till transplanted by machine into a
roll-crimped cover crop of
wheat at North Carolina A&T
State University, Greensboro.
• Reduce tillage and waiting
period after cover crop.
• No-till cover crop roll-down
and vegetable planting.
• Practical for tomato, pepper,
broccoli, cabbage, other
transplants, potato, garlic,
squash, beans.
• Possibly cucumber, melon.
• Not suitable for beets,
carrots, direct-sown greens
 spading machine for onepass cover crop tilldown.
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38. Practical considerations: green manure cover
cropping
Pros:
 Readily-available food for soil life
 Maximizes active organic matter
 Biofumigation (brassica covers)
 Fine seedbed for direct-sowing
 Accelerates nutrient release
Cons:
 Tillage burns up SOM, disrupts soil
fungi & earthworms
 May lead to crusting, erosion
 Stimulates weed emergence
Plow-down vetch green
manure feeds soil life,
releases N, facilitates
seed bed preparation.
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39. Practical considerations: roll-crimping
Pros:
 Maximizes stable and total
organic matter.
 Continuous soil coverage.
 Reduces emergence of annual
weed seedlings.
The roller-crimper terminates  Soil fungi, earthworms
mature annual cover crops
undisturbed.
like this without tillage or
Cons:
herbicides.
 Slower nutrient release.
 Lower soil temperature.
 Cannot direct-sow fine seeds.
 Perennial weeds may increase.
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40. Why it Works: Strengths of the System
- energizing with diversity
• 20 vegetable crops from
11 plant families.
• Cut flowers in rotation add
more diversity.
• 9 cover crops from 3 plant
families.
• Each crop fosters a unique
soil microbiota in its
rhizosphere.
Diversified crop rotations
support a wider diversity
of life below ground, thereby
enhancing soil fertility and
soil quality.
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41. Why it Works: Enhancements to
consider to increase diversity
• NRCS soil health teams
in Greensboro, NC and
in North Dakota are
planting cover crop
mixes of 5 – 10 species
from 3 – 5 families.
• Increased benefits to
soil quality and cash
crop yield are seen
compared to grasslegume biculture.
Some examples:
 Rye, oats, hairy vetch, crimson
clover, Austrian pea (winter –
commercially available)
 Rye, wheat, oats, tillage radish,
Aus. pea, crimson clover, vetch,
turnip, mustard (winter – NRCS
trials in VA)
 Sorghum-sudan, pearl millet,
cowpea, buckwheat, sunflower
(summer – used in home garden)
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42. Building Soil Organically: A Discussion of
Practical Applications and Why They Work
Bo Holland
Screech Owl Farm
Nelson County, VA
Daniel Parson
Oxford College Farm
Oxford, GA