Fertility Management at Roxbury Farm
A Personal Narrative
Introduction
page 3
Chapter 1 Physical Properties
page 4
characteristics of good vegetable land
Chapter 2 Soil Structure and Tillage
page 4
page 5
characteristics of stable structure
page 5
strategies to support stable structure
page 5
purpose of tillage
page 6
planting system for vegetables
page 7
Chapter 3 Biological Fertility
page 9
introduction
page 9
compost
page 10
compost process at Roxbury Farm
page 10
compost to offset losses in crop production
page 11
Cover and Green Manure crops
page 12
advantages of cover and green manure
page 12
disadvantages of cover and green manure
page 14
what we seed what month
page 14
Compost or green manure/ a cost analysis
page 15
Crop Rotation
page 15
introduction
page 15
crop plant families
page 16
plant families in rotation
page 17
record keeping of rotations in MS Excel
page 18
sample crop rotations
page 21
disease problems and efficacy of crop rotation
page 22
insect problems and efficacy of crop rotation
page 24
Biodynamic Preparations
compost preparations
page 26
page 26
chamomile
page 27
dandelion
page 27
yarrow
page 28
nettle
page 28
oakbark
page 29
valerian
page 29
The field sprays
page 30
hornmanure
page 30
hornsilica
page 31
© Jean-Paul Courtens 2010
Page 1
Chapter 4 Soil Chemistry
page 32
Cosmic and terrestrial nutrition
page 32
Different schools of thinking on plant nutrients
page 33
Application and removal of plant nutrients
page 34
Assessment of fertilizer needs
page 35
Cation Exchange Capacity (CEC)
page 36
Soil pH
page 36
Plant Minerals
page 38
Nitrogen
page 39
Phosphorus
page 39
Potassium
page 40
Silica
page 40
Calcium
page 40
OMRI sources of plant minerals
different compositions of manure types
page 41
page 42
The correct balance of wood, orchards, bushes, and meadows – with their natural growth of fungi
– is so essential to good farming that your farm will really be more successful even if this means a
slight reduction in your tillable acreage. There is no true economy in using so much of your land
that all the things I have mentioned disappear. The resulting loss in quality will far outweigh the
advantage of the other things. Without this kind of insight into the interconnections and
interactions of nature, it is really almost impossible to engage in an enterprise like farming which
is so closely bound up with nature.”
Rudolf Steiner June 15, 1924
© Jean-Paul Courtens 2010
Page 2
Introduction
Our perspective on soil is modified as soil scientists expand their insight uncovering its secrets.
We are constantly provided with new tools that allow us to improve our management practices.
This document will never be static as we do not have the pretense that the following should be
seen as an ideal system of management but rather a description and explanation of our present
practices.
Soil scientists assess soil quality from three perspectives; the physical, chemical, and biological
characteristics. The physical characteristics though can be described from two very distinct
perspectives. One part can be called the phenotype, the part we can improve through
management practices, while the other can be called the genotype, the soil as we find it and the
characteristics it has in how it was geologically formed. In some ways structural fertility is the
result of good management of the physical, biological, and chemical components that make up
our soil. In this document we distinguish four different qualities to assess the fertility of a parcel
with regards to the best possible use.
Soil
Chemistry
Soil Health
Soil Structure
Biological
components
Physical
Properties
Important Footnote:
The newest version of building better soils for better crops by Magdoff and van Es offers the best foundation to gain a
thorough understanding in the many aspects involving soil health (The above graph is an interpretation taken out of that
book). Some relatively older books like "Bemesting en Meststoffen" by Ir Rinsema, and "Green Manuring" by Adriaan
Pieters (neither one of them are still in print) and Lievegoed "Planetary Forces and Life Processes" served as important
sources of information for this manual. The "Agriculture Course" by Rudolf Steiner is an important source of inspiration for
the particular farming methods at Roxbury Farm. This manual is written from the perspective of the author based on the
unique conditions and his practical experience at Roxbury Farm in Kinderhook, NY.
© Jean-Paul Courtens 2010
Page 3
1. Physical Properties
There are about 350 acres under Roxbury‟s management.
What crop is growing on it is a direct result of the soil type we are working with. The presence of
large rocks, steep slopes, or poor drainage makes some of this land unsuitable for vegetable crop
production.
Good vegetable land has:
Some of the bottomland, seen from the Van Buren field
-High carrying capacity (carry the weight of
equipment
without
creating
irreversible
compaction)
-Good natural or artificial drainage
-Good access to irrigation water
-Deep A horizon (topsoil) that is free from stones
-Almost flat with slopes that do not exceed 2%.
-Located in a long season micro climate
-Good exposure to sunlight
-Good air drainage to avoid late spring frosts.
-Good access to farm roads
-High CEC
At Roxbury Farm of the 120 Acres that are suitable for vegetable crop production, only 45 are
planted in cash crops while another 45 acres are planted in soil improvement crops with the
remaining 30 in tall fescue and orchard-grass combined with ladino and red clover for hay.
Almost all of the vegetable land is rated category I or II (Occum, Unadilla, Knickerbocker, and
Hoosick). The material ranges from coarse sand to a fine silt loam. The remainder of the land at
Roxbury is divided between hayfields, pastures, woods, or wetlands. Those places are important
in providing feed for our livestock and biodiversity to complement the land committed to cash
crops.
When we assess the physical quality of our soils, we determine its physical strength and
limitations. Working land can be like working a horse. First, we need to understand what horse
we are dealing with. Is it a workhorse or a riding horse? Each has different qualities. We will not
try to pull a heavy load with a riding horse for a prolonged period of time. Within this analogy, our
sandy soils are like riding horses. The usefulness of a riding horse is in its speed; while it might
pull a plow, it lacks the persistence of a workhorse to complete the task. Sandy soils are great in
the early spring since they drain well and warm up quickly. This allows us to work these fields
earlier than others. But in the summer, they easily dry out, and can only achieve good yields with
irrigation. Our sandy soils do not hold nutrients well and the lack of clay and low percent of
organic matter is confirmed in the relatively low cation exchange capacity (CEC). A heavier soil,
like a silt loam resembles a workhorse; it works harder at an initially slower pace but with much
greater resilience. Silt loam soils warm up a little later in the spring but their ability to hold
nutrients and water gives them a great advantage during the summer months.
It has proven more difficult to build organic matter on a sandier soil with large granular particles
compared to the soils that contain smaller particles or some clay. Nutrients tend to drain out of a
coarser soil and leaching of nitrogen and other mineral fertilizer can be a problem. The buildup of
organic matter and nutrients are like the muscles and fat on a horse‟s body. At times when lots of
work is demanded it has the reserves to complete its task.
Starting off with a good soil is the best investment a vegetable grower can make. Altering the
state of the soil besides drainage and rock picking is hardly ever cost effective compared to the
cost of prime farmland. Building organic matter and increasing structure do not alter the state of
the soil as they merely improve what is already there.
© Jean-Paul Courtens 2010
Page 4
2. Soil Structure and Tillage
Structural fertility is reflected in the way soil-particles are connected and organized in relation to
each other. We evaluate how the soil particles are spaced and how many and how large the
spaces are in between them. The use of tillage tools and the compaction of tractors can cause
the soil aggregates to fall apart as it disrupts the subtle balances that exists in a virgin soil. When
aggregates separate into their original components of sand, silt, clay, and organic matter, soils
tend to collapse and erode when exposed to the elements. Soils with stable aggregates hold up
better when exposed to heavy rain, tillage, wind, etc. Some soils have better physical
characteristics to create stable aggregates than others. The Soil Health Team at Cornell
University has created a soil test which measures bulk density, water stable aggregates, and
other parameters so farmers can evaluate how their practices create or destroy soil structure.
A stable structure will have:
 An equal distribution between mineral particles
and pores.
 Good ability for roots to penetrate.
 Good ability to hold water.
 Good ability to drain excessive water.
OM
Rye pulled up after spading; soil is held together and the clumps are smooth and round
Soils in hay fields (where manure is applied), in pastures or in cover
Air
Mineral
cropped land are able to maintain a good structure. The decaying
roots, the applied manure, or worked in green plant matter support
Water
many microorganisms that jump start the food chain which results in
increased soil activity. With the grasses providing a source of
carbonaceous materials and the legumes the necessary nitrogen,
together they provide the building blocks for the microorganisms in
the soil. This increased activity connects the soil particles into aggregates. As the broken down
organic matter acts like glue between the particles; the extensive root system of the grasses
holds the soil together. Decaying roots and increased soil activity creates pores, which provide for
drainage and capillary action in times of drought. Vegetables with their poor root development
and need to expose the land tend to degrade the soil structure rapidly creating a need for artificial
structure by means of mechanization.
Strategies to support good structure are:







Add organic materials with high humus conversion rates (containing fiber and lignin) to
increase organic matter.
Add green plant matter or raw manure which increases the water stable aggregates.
Add calcium as building block for clay soils to improve its structure.
Avoid breaking up the soil beyond natural breaking points.
Increase permeation by root systems with crops like sweet clover, chicory, rye with vetch etc.
Increase root activity by using biodynamic preparation 500.
Using frost as an action to fracture compacted soil.
To help determine how we treat the soil during the season, the tillage tool should not fracture the
soil more than when a clump of soil is dropped from a height of three feet. It is ideal to use tillage
equipment that has an action similar to that of a hand-fork. A hand fork fractures the soil at the
© Jean-Paul Courtens 2010
Page 5
soil‟s own breaking points. A spade damages
the aggregates where it slices the soil. The
coloration at the back of the spade (which acts
like a plow) is an indication of smeared soil
particles. The aggregates that allow the soil to
stay cohesive have come apart.
Five different purposes of tillage:





Fracturing hardpans with a sub-soiler;
depth one or two inches below hard or
plow-pan.
Aeration of the soil; Depth anywhere
The shank of a Yeoman Sub Soiler.
between 8 and 12 inches (top-soil only).
Incorporation of organic material; How deep do you want to put your organic material?
Creating a seed or plant-bed; How smooth and level, and free of plant debris depends on the
crop to be grown and the type of seeders and row cultivation tools we have.
Weed Control
Conventional equipment rarely combines all tasks. Only a tractor with a front mounted subsoiler
and a rear mounted spading plow with secondary
attachment will accomplish the first four tasks,
when a relatively rough seedbed is sufficient.
To establish the depth of the hardpan we use a
penetrono or tensionometer. This is a rod
attached to a pressure gauge that reads the
resistance the soil gives when the rod is forced in
the soil. We found a hardpan at about 12 inches
which is deeper than the plowing depth. Plowing
is not the only cause of hardpans and this
compaction was most likely caused by the use of
Yeomanplow breaking up hardpan in sod after first cutting of hay
heavy equipment.
n the right: To break this
hard pan we use a Yeoman plow which is set just
two inches below the hardpan. Sinking it deeper than this is a waste of diesel as the force
needed to penetrate any deeper might cause additional compaction. In subsequent seasons we
might choose to sink our sub-soiler even deeper until all the disturbing layers are broken. It is
important to follow a sub-soiler with a crop like yellow blossom sweet clover that completes the
mechanical action of a sub-soiler.
For primary tillage, a Coulter Chisel plow or an
Imants rotary spading plow is used to aerate
the soil. In order to incorporate cover crops the
use of a rotary mower (which needs to have
more than one set of blades to avoid
windrowing) or flail-mower is necessary. The
chisel plow does not turn the soil and leaves a
lot of plant residue on the surface (which btw
should never referred to as trash). Afterwards,
the land is left quite rough so subsequent
passes of a disc harrow followed by a S-tine
cultivator harrow are used to smooth out the
field. This last tool consists of a combination of
several “S” tines, a leveling bar, and a set of
© Jean-Paul Courtens 2010
Coulter chisel plow with S tine attachment incorporating potato vines
Page 6
crumbling rollers. It leaves the soil level and
smooth to plant cover-crops, certain cole crops,
potatoes, and squash.
Alternatively, the
spading plow is able to incorporate (as the
picture above demonstrates) a thick stand of
sweet clover in one pass. A great disadvantage
of the spading plow is its speed (up to 2½ hrs
compared to 20 minutes per acre for a coulter
chisel plow). For precise placement of small
seeds and optimum weed control we need a
very level seedbed. To obtain this we use a
bed shaper.
For crops that have small seeds and that
Rotary spading plow with power harrow working in sweet clover
require extremely level ground with no clumps or stones on the surface a Bed Shaper is used
both after the use of the spading plow or the Perfecta II cultivator. This tool leaves a trench every
72 inches, creating a soil surface that
resembles raised beds.
The planting surface of the bed is 54
inches wide and allows for:
 One row of squash, tomatoes, melons,
cucumber with 72 inches between
each row
 Two
rows
of
potatoes,
corn,
cauliflower, broccoli, cabbage, kale,
rutabaga, fennel, celery, green beans
with 36 inches between each row
Bed shaper (modified Buckeye) leaving a smooth and level surface for seedbed
 Three rows of lettuce, beets, onions,
carrots, basil, parsley, mei-ching-choi,
broccoli rabe, turnips, celeriac, with 18 inches between each row
 Five rows of baby carrots, radishes, with 9 inches between each row
 Nine rows of salad mix, arugula, spinach, cilantro, dill with 4½ inches between each row
72 inches
18”
row 1
row 2
row 3
row 4
row 5
row 6
row 7
row 8
row 9
The trenches prevent the roots from suffocating during periods of heavy rain. The crops keep
their "feet" dry, as the water flows off the top of the bed into the trenches. The combination of
better drainage and the level plant bed prevents some bottom rot but its real value is by creating
correct conditions for successful mechanical weed control and to avoid compaction with future
passes. the top of the bed is never driven on after primary cultivation.
The chart below shows the number of passes needed in each system:
Cover Crop with small seeded legume
Vegetables
Sub-Soiler 1x
Sub-Soiler 1x
Coulter Chisel Plow 1x
Spader 1x
Disc Harrow 1-2 x
Culti-Mulcher 1x
Bed Former 1x
Grain Drill 1x
Seeder or Transplanter 1x
Culti-Mulcher (to roll) 1x
Row Cultivation Equipment 2-3 x
© Jean-Paul Courtens 2010
Page 7
To avoid future compaction:





Avoid at all circumstances to work the soil when it is too wet. Form a ball out of the soil
to be worked; it is safe to work soil when it crumbles after release. If the ball remains
intact you will risk compaction and smearing of the soil with tillage equipment.
Lowering tire pressure in tires to possibly 6-10 psi for field preparation (on our main field
tractor we keep the rear tires at 12 psi and the fronts at 20 psi to avoid excessive wear)
Use wide radial tires and 4 WD for field preparation
Ballast your tractor so wheel slippage is around 10-15% when pulling tillage tools.
Use light tractors with narrow tires in controlled field traffic (trenches of raised bed are the
traffic lanes) for transplanting, spraying and weed control
Weed Control Cultural Practices:








Reduce tillage
Alternate cereal/legumes with vegetables in crop rotation
Allow for bare fallow between cover crops and vegetables
Precede summer bare fallow for summer vegetables and spring bare fallow for spring
planted vegetables
Cultivate when weeds are in the white germ stage; once you can see them you missed
the best opportunity for complete eradication
Prepare seedbed only to the depth of seed placement (¼ to a full inch only) when a stale
seedbed is required (carrots leafy greens etc)
Cultivate weeds with equipment that does not bring up new weed seeds
Remove weeds before they go to seed to avoid building up seed bank
Weed Control Tools used at Roxbury Farm:


Lely Tine Weeder in potatoes and snap beans
Basket Weeder for very first cultivation in carrots, beets, lettuce and other fine seeded
crops
 Bezzerides Spring Hoe as first cultivation in most transplanted crops (except for lettuce)
like sweet corn, cole crops, and large seeded crops like snap beans and peas.
 Rear mounted Side Knives to complement spring hoes or basket weeder
 Rear mounted parallel suspended S tines to complement Spring Hoes for more
aggressive cultivation.
 Lilliston Cultivator for aggressive hilling in potatoes, cole crops and sweet corn
 Hillside Cultivator for aggressive cultivation in plasti-culture
 Unverferth Perfecta II Combination Seedbed maker for bare fallow cultivation
 Unverferth Perfecta II Bedder for stale seedbed
For more info see crop manuals.
Bezzerides Spring Hoes cultivating Brussels Sprouts
© Jean-Paul Courtens 2010
5 row Buddingh Basket weeder set up for stale seedbed
Page 8
3. Biological components
Here we recognize three areas of importance:
-The cycles in nature, that includes decay and decomposition of organic matter.
-The creation and maintenance of soils.
-The nutritional value of cultivated plants.
According to Elaine Ingham when virgin prairie land, the archetype for a healthy soil ecosystem
is plowed, no pesticides or fertilizers are needed for the first 5 to 15 years. I have no direct
experience with virgin land but we all recognize that disease-suppressive bacteria, fungi,
protozoa, and nematodes can protect plants from infection, while the natural nutrient cycling and
nitrogen retention provides the crops with their nutritional needs. By exposing the soil to the
elements, we diminish the number of beneficial organisms and burn up the organic matter. When
no new organic matter is returned, we not only stop feeding the beneficial organisms we slowly
deteriorate the characteristics of the soil. This process is not any different from overgrazing
pasture land. Overgrazing reduces diversity and population of grasses and clovers in our
pastures just as working the land reduces the microbial population of the soil. A reduction of
these organisms eventually results in disease problems. The challenge of organic farming is to
maintain a balance between what is taken from the land and what is returned to the soil without
shortcuts like the use of artificial fertilizer or pesticides that cause even greater reduction of soil
organism. According to Elaine, one teaspoon of healthy soil should contain about 600 million
bacteria, three miles of mycelia, 10,000 protozoa and 20 to 30 beneficial nematodes.
Recognizing the processes that happen in the soil can help make a contribution maintaining a
healthy ecosystem. Nutrients removed from the field have to be returned to close the cycle. This
type of nurturing is not unlike any other type of husbandry. We need to distinguish the nutritional
requirements of the different creatures that live below the surface of the soil. This process is
similar to putting cows on lush pasture. A good farmer feeds all its animals even the ones that
can only be seen with a microscope.
organic matter in tons/acre
68
Cropland
Sod
Cropland
64
60
56
Total Organic Matter
54
50
5
10
15
20
Based on bemesting and meststoffen by ir W. T. Rinsema et al
25
5
10
Time in Years
Spreading compost has a different effect on soil life and soil quality compared to spreading raw
manure or plowing under green manure. Compost is a finished product with little available
carbon left as a food source for microorganism. We make a distinction between the raw and
stable components of the organic matter in the soil. Raw organic matter like plowed down green
manure or animal manure provide the microorganism with many readily available nutrients. This
increased microbial life protects those nutrients from leaching into the groundwater as they
become part of their cell structure. Soil building crops and raw manure have showed to increase
the water stable aggregates in the soil as their properties act like glue between the soil particles
© Jean-Paul Courtens 2010
Page 9
Ultimately a healthy soil transforms this raw organic matter into humus, which is the most stable
form of organic matter:
Humus has the ability to absorb both nutrients and water. Its negative charge gives it the ability
to absorb positively charged nutrients like K, Mg, Ca, etc. Compared to clay, which has the ability
to hold nutrients and water, humus can hold up to four time more. The nutrients absorbed by
humus are available to plants but cannot be washed out by excessive rainfall. Humus also
increases the structure of the soil as it becomes part of a water stable soil aggregate.
At Roxbury Farm we maintain a healthy soil ecosystem by applying compost, the cultivation of
soil building crops, the application of broad rotations, and the use of the biodynamic preparations.
The following four sections will describe in detail the importance of each component.
A. Compost:
Compost as a finished product provides little means of carbonic nutrition for the microorganism
while it does increase the soil‟s long-lasting organic matter. Compost is an important source of
nutrients so it should be treated as a fertilizer input that also builds soil. Good compost can
introduce new beneficial organisms which could help suppress plant disease. Roxbury Farm
presently purchases compost from a local source that uses a mix of cow manure, horse bedding,
and woodchips. Good compost should ideally have a C/N ratio of 10/1, and should be free of
pathogens and weed seeds, while excellent compost adds a disease suppressing component.
The process of making compost at a Roxbury Farm:
During the winter, the animals are kept in a free-stall setup (we use a greenhouse which allows
for a dry, well lit and relatively warm environment during the winter). In this method, the hay is
fed in the form of round bales and placed inside a feeder on top of the packed manure. The
animals are kept clean by applying bedding on a regular basis. This can consist of old hay,
straw, and/or wood chips. As an unheated greenhouse is subject to collapse during heavy
snowfall we added support braces to the trusses (see picture) creating the outline of the feed isle.
The sows are kept in separate stalls and all animals have outside access which guarantees their
health and well being. Sheep continue to graze all through the winter provided a light snowpack.
After six months, the packed materials can be about a foot deep. In May, the manure is removed
with a skid steer or mini excavator. The pile is built with a manure spreader, with its final shape
created by a compost turner. The biodynamic preparations are inserted into the pile by pushing a
long stick two feet into the pile. Only small amounts are needed in each hole to ensure the
beneficial activity.
Greenhouse converted to barn space with feeding isle in the middle
© Jean-Paul Courtens 2010
The structure provides shelter for 50 ewes (and their lambs in the
spring) and 2 sows (and their litter in the spring)
Page 10
A variety of materials in a
manure-pile allow it to be
mostly self-sufficient in
the
process
of
transformation. A diverse
mix of materials develops
a combination of aerobic
and
semi-anaerobic
bacteria. The piles heat
up 120° to 160° F. and
stay at that point for quite
a few weeks. A specially
designed cover is placed
over the piles to shed of
any excessive rain and to
keep the moisture in the
Compotex© covers to help retain nutrients and
pile. The cover functions
moisture in compost pile and to protect
groundwater against pollution.
like a skin. It protects the
pile from the elements without choking it. A pile has
characteristics like any other animal on the farm: it breathes, consists mostly of water, and has
body warmth, so daily observation is needed. When the piles dry out water needs to be added;
when the piles heat up beyond 160 F˚ we need to stamp it down as excessive heat will burn up
the pile leading to excessive losses, while when it is too cold, we need to turn it to re-activate it.
Completely “finished” compost deprives the microorganisms in the soil of nutritional carbon, so
the whole process of composting takes only about 6 to 12 weeks. The compost, when applied is
not “finished”, but will have lost most of its odor. The most important objective of transforming
raw manure into compost is to kill pathogens like E-coli and to "cook" the weed seeds. The ideal
time of application is on a cloudy day with plenty of rain in the forecast. After application, the
ground is chiseled or spaded. Manure handling can be the weakest link in the farm‟s fertility
cycle. At a biodynamic farm, it is important to keep nutrient and OM losses as low as possible.
AMOUNTS OF ORGANIC MATTER OF DIFFERENT CROPS REMAINING AFTER HARVEST IN SAME YEAR AND FOLLOWING.
All numbers in lbs. /acre
Based on bemesting and meststoffen by ir W. T. Rinsema et al
Crop
Underground
Above ground
Total
Remains after
one year
Rye
1100
3300
4400
1350
Oats
1250
3300
4550
1400
Potatoes
450
3150
3600
750
Beets
450
300
750
250
Cabbage
900
3600
4500
1000
Peas
350
1400
1750
400
Beans
350
1400
1750
400
Onions
Grass-clover
270
180
450
130
1 year
2250
1350
3600
1050
2 years
6000
1350
7350
2300
3 years
9500
1350
10850
3600
1 year
1800
900
2700
700
2years
2700
1350
4050
1200
3years
4500
1350
5850
1850
3270
3000
Alfalfa
© Jean-Paul Courtens 2010
Compost 10 ton
Page 11
As the chart above shows vegetables do not retain organic matter in the soil. Besides their poor
ability to fix carbon they also cause greater breakdown of organic matter due to cultivation. Open
and cultivated land burns up about 2% of its organic matter each season. Living organic matter
burns up at much higher rates than to called dead Organic matter. This breakdown allows our
cash crops to thrive as minerals including nitrogen are released out of the OM to the crops. To
offset the losses we apply compost. As compost brings in more minerals than our cash crops
remove (especially phosphorus) we need to maintain the OM levels with cover crops or sod. If
the total weight of an acre of soil is 2,000,000 lbs, and its OM fraction is 3%, the total weight of
the OM fraction is equal to 60,000 lbs. 2% loss on 60,000 lbs of OM is equal to 1200 lbs per
year. The graph on page 8 shows how quickly organic matter is lost, and how long it takes a sod
to build it back up. The chart above also shows that rotations that do not include imported
compost need to complement the plowing under of full stands of green manure crops to maintain
organic matter levels.
Fibers play an important role in the composting
process. Most fibers are “used up” at the end of the
composting process. Hay and straw are good
examples of being good energy providers for the
microorganism.
Their presence is vital in the
process, but it is important to include materials that
contain lignin. They take a longer time to break
down, and this kind of carbon compound is not
readily available as an energy source for the
microorganisms. But at the end of the composting
process, they contribute to the formation of humus
at a much higher rate than fibers do.
a 14 foot mower is utilized to clip the green manure crops
All carbonaceous materials have a different conversion rate in becoming humus. Materials with
high lignin fractions like peat moss, woodchips, and leaves have a high humification co-efficient
factor. This means that a high portion of the original carbon will eventually become humus.
Materials with easily digestible carbon like hay, straw, and manure have a much lower factor.
The latter group is an essential component of compost as it contributes nitrogen and other
building blocks that are used by the microorganism to grow and multiply. Over time the wood
chips and leaves (very low in nitrogen) will break down at albeit a much slower rate.
The eventual goal in applying good compost to the land is to increase the overall health of the
soil. Compost is an effective remedy when our goal is to increase the organic matter level of our
soils. Disadvantages are the steady increase of minerals in the soil which can create
unmanageable weed problems. High applications of compost on organic vegetable farms have
caused many persistent problems with weeds like chickweed, galinsoga, and purslane and
possible leaching of phosphorus into the ground or surface water. Therefore it is wiser to
maintain soil organic matter through a combination of compost and cover crops.
B. Cover and or green manure crops:
Why we use Cover and or Green Manure Crops:
 Reduction of nutrient leaching
Soluble nutrients are easily washed out over the winter months unless they are taken up by a
cover crop.
 Reduction of soil erosion
A crop of rye seeded in September and plowed under in April is able to keep the soil from
eroding away over the winter months. Rye and hairy vetch as a mix are very effective, as
they will add to soil-life and increase the mineralizable nitrogen fraction. Although if plowed
© Jean-Paul Courtens 2010
Page 12
early, the humification co-efficient can be
low, soil life is greatly benefited by the mere
fact that the ground has not been left
exposed. The roots of the cover crops after
breakdown form the very important
capillaries for drainage as well as water
uptake.
 Increase of pores in soils and breaking up
hard pans
Sweet clover is known for its deep
penetration of the soil and breaking of hard
pans. But any established grass will greatly
A mix of peas and sweet clover
increase the amount of pores in the soil.
Presence of oxygen promotes breakdown of dead organic matter as it increases microbial
activity.
 Increase in soil life activity
Soil particles are held together by soil life activity esp. by the group of mycorrhizae. The
cover crop roots provide the needed sugars and amino acids for the activity of the
mycorrhizae. Mycorrhizae provide the plants with better uptake of minerals esp. phosphorus,
and allow the plant to absorb water more efficiently by enlarging the root hairs. Seventy-five
percent of seed bearing plants have a symbiotic relationship with mycorrhizae unless they
are destroyed by the use of mineral fertilizer. Deriving fertility and esp. nitrogen from the use
of cover-crops in reaction with nitrogen fixing bacteria allow for a beneficial environment for
mycorrhizae. A good example is our heavy reliance on both bell beans and oats to provide
the necessary fertility for demanding crops like cauliflower. The beneficial environment
created by the growth and eventual breakdown of the bell beans allows for more efficient
nutrient uptake by the cauliflower.
 Increase in Organic matter content through carbon intake
Grasses are known for their excellent ability to fix carbon out of the air. For greatest uptake
of carbon in one season, Japanese millet and sorghum-Sudan are favorites. To avoid
reduction of nitrogen content due to breakdown mix these crops with forage soybean (not to
be confused with regular soybeans)
 Fixation of Nitrogen by legumes
Nitrogen fixing bacteria, which exist in symbiosis with the roots of the legumes fix nitrogen out
of the air and form ammonia. Look at the roots of the legume to find out if nitrogen is being
fixed: if the roots have nodules that are red or pink colored inside, it has active bacteria. If
the roots do not show nodules, find out if the soil pH is too low or if the particular bacterium is
in your soil. Many legumes live in symbiosis with different bacteria. Rhizobium japonicum
lives in symbiosis with soy beans, Rhizobium trifolii with clover, Rhizobium meliloti with
alfalfa. These crops are usually inoculated with the bacteria before planting. Azobacter
species are free living bacteria capable of fixing nitrogen. Efficient legume crops are bell
beans, field peas, hairy vetch, sweet, red and ladino clover, and forage soybeans.
 Weed management
Many crops are able to choke out other
weeds. By using short season cover
crops we reduce the number of weeds
going to seed. This results in reduction
of labor needed in the cash crops
 Plant disease management
Most cover crops are in a different plant
family than our cash crops. By allowing
cover crops to grow a full season and
become part of the crop rotation, disease
and insect cycles can be broken. This
results in increases of yields in the cash
Buckwheat flowering in late July early August
crops at lower labor costs, due to
© Jean-Paul Courtens 2010
Page 13
increased efficiency of harvesting and sorting. Some
diseases and insects affect a variety of plant families. It is
important to take great care when planning your rotation
and to be aware diseases and insects that might be
caused or carried by the cover crops. On the other hand
mustard and sorghum can act as a bio-fumigant. Mustard
and sorghum, when properly plowed under, can reduce
incidences of Verticillium wilt, Rhizoctonia root rot,
Fusarium wilt, and Pythium root rot.
 Overall farm diversity
Most insects feed off the pollen of the grains and grasses
when they are left to mature. In some instances, the cash
crop acts as a host to beneficial insects. The pollen of the
sweet corn is a good example as they provide food and
habitat for the trichogramma parasitic wasp. For that same
reason, parsnips can be left in the ground to flower in the
spring. Dill, another member of the Umbelliferae family
can serve the same function. After the dill is cut for
Sweet Blossom Clover in late June, early July
market, the plants remain alive and produce flowers at a
time when the parsnips have gone to seed. Green manure crops provide a source of nectar
to wild bees and we try to have at least on cover crop in full bloom during the growing
season.
Disadvantages of cover crops:
Grains and alfalfa is a host for thrips, tarnished
plant bug, and leafhoppers. Once the grain is
combined or the alfalfa cut, the many insects
including thrips and leafhoppers look for a new
home. As we increased our acreage in grains and
legumes our problems with thrips and leafhoppers
increased. Our solution has been to have another
crop available (besides the vegetables) for the
insects to migrate to and to never mow all the
cover crops at one time.
Sod can provide a cover for the eggs of many
insects.
Flea beetle and carrot-fly take
advantage of this environment over the winter.
Dandelions flowering in late April
Another detriment from too much raw organic
material is the residual activity in the soil that can have the same effects as fresh manure. Many
diseases and pests like aphids increase when too much raw fertility is applied. We also noticed
higher root rot ratings due to pythium or rhizoctonia as clover is a host to both diseases and esp.
rhizoctonia thrives under high OM conditions.
What we seed in different months in New York:
April and May: Bell Beans/Oats, Field-peas/Barley or Oats, Oats as nursing crop for Sweet, Red
Ladino clover, or Alfalfa, Rye with Dutch White Clover and small Fescue Grass
on head lands and harvest lanes (rye will not form a seed head when seeded in
the spring).
May and June: buckwheat, Japanese Millet or Sorghum-Sudan with Forage Soybean.
July:
Red clover, Buckwheat, Japanese Millet or Sorghum-Sudan with Forage
Soybean, Annual Rye Grass.
August:
Red and Sweet Clover, Oats and Peas, Oats and Peas and Hairy Vetch.
September:
Rye and Hairy Vetch, Oats or Barley and peas, Oats and Hairy Vetch, Oats.
October:
Rye, Winter Wheat.
© Jean-Paul Courtens 2010
Page 14
COST OF ORGANIC MATTER AT ROXBURY FARM: MOWING VERSUS COMPOST
Costs
Hours used
Acres used
Cost per hour
Roxbury
Tractor 100HP
300
$
Tractor 75 HP
300
$
45.00
Rotary mower 15 feet
36
$
47.50
$
12.00
180
labor
Cost per acre
Total cost per year
50.00
$
17.00
$
3,000.00
manure spreader
40
35
$
22.00
$
84.00
$
2,900.00
harrow 12 feet
31
200
$
25.00
$
9.50
$
2,000.00
grain-drill
25
70
$
40.00
$
23.00
$
1,700.00
$
40.00
land
First we need to determine the cost of our equipment. Based on our limited use our costs are higher than the national average listed at
most universities.
Costs and return
compost
OM gain equal to 1 yr
mowing
Om gain equal to 2 yr
mowing
Om gain equal to 3 yr
mowing
yards
cost per 20 yards
cost of spreading
value of minerals
total cost
cost per 1 K lb
gain of OM
6
$
150.00
$
27.00
$
87.00
$
90.00
$
100.00
14
$
350.00
$
60.00
$
200.00
$
210.00
$
100.00
22
$
550.00
$
94.00
$
314.00
$
330.00
$
100.00
We know the cost of compost per yard and the value of minerals if purchased separately (OMRI listed). The remainder is the additional
value of the OM. Spreading compost is significantly more expensive than mineral fertilizer as only a portion is plant nutrient, a large portion
consists of water, silica and OM.
Costs and
return mowing
seeding per acre
seed per acre
mowing four times
value of nitrogen
One year
$
42.00
$
two years
$
42.00
three years
$
42.00
land cost
60.00
$
68.00
$
108.00
$
$
60.00
$
136.00
$
216.00
$
60.00
$
204.00
$
325.00
total cost
40.00
$
102.00
$
97.00
$
80.00
$
102.00
$
44.00
$
120.00
$
101.00
$
28.00
The two greatest factors in determining if green manures or sod are cost effective in raising the OM levels is dependent on the duration of
the crop grown and the cost of land. If sod is hayed, we can add the sale of hay, but will need to deduct the cost of nutrients taken off the
land to make a new analysis. Most lasting OM and N is formed in the soil by plant-roots.
C. Crop rotation:
Within the vegetable land we have a system of permanent sections, that each contains eight
beds. Permanent sections allow easier record keeping of where the crops have grown and aid in
exact planning. There is no guesswork in finding where last year‟s crop was planted. The
harvest lanes also serve as a means to easily reach to the cash crops, a place to pull in the
irrigation reel, and as habitat for the bees (since they mostly contain white clover).
Crop rotation is a tool used to break insect, weed, and disease pressure in the vegetable fields.
There are many reports of increased yields of cash crops in fields that adopt rotations. In organic
agriculture, we should not only rotate within the plant families of our cash crops but also include
grasses and legumes in our rotation mix. As seen in the chart on page 8, they fix decent
amounts of organic matter and introduce a broad spectrum of soil life to the farm. They can also
form a habitat for beneficial insects. They are a neutral crop in our rotation since they rarely host
diseases that affect our cash crops. Proper incorporation and time to let the soil digest the plant
© Jean-Paul Courtens 2010
cost per 1K lb
gain of OM
Page 15
matter is important. Too much raw organic matter can greatly affect the health of our cash crops
in a negative way. Introduction of bare fallow periods in “neutral” years are effective in breaking
up both weed cycles and the incorporation of large amounts of plant matter.
The overriding factor in creating a field plan on
a CSA or other diversified farming operation is
to have easy access to the crops. In order to
give a minimum rotation of three years between
the plant families we can choose to either plant
all the same genotypes in one field or to expand
our arable land to include more than vegetable
crops. At Roxbury we rotate vegetable crops
with grains, legumes, and grasses. Diseases
prevalent in vegetables are generally not carried
over by a grass or cereal crop and to a small
degree by legumes (legumes can be the carrier
of many soil pathogens or their plowdown can
Early morning harvest of greens and salad (picture P.Lowy 2002)
reinvigorate their development) Allowing for a
diversity of families in one field creates more efficient harvesting conditions. In this method, the
crew is able to harvest all the salad and cooking greens as well as the culinary herbs from one
section, and moves to another field for the late morning harvest of cukes and tomatoes. As crops
in the previous example generally mature around the same time, all the ground can be worked up
in order to plant a cover crop.
At Roxbury the different plant families are:
Apiaceae or Umbelliferea:
Asteraceae or Compositae:
Brassicaceae:
Chenopodiaceae:
Convolvulaceae:
Cucurbiticeae:
Fabaceae
Liliaceae or Alliums:
Poaceae:
Rosaceae:
Solanaceae:
carrots, parsnips, parsley, celery, dill, etc
all the lettuces, escarole, and certain cut flowers.
all the Cole crops including broccoli, arugula, turnips,
all beets, chard, and spinach.
sweet potatoes
all cucumbers, melons, squashes etc.
or legumes: peas and beans.
all the members of the onion family
all grains including sweet corn.
strawberries
all nightshades, including potatoes, eggplant, peppers,
tomatoes, etc.
Shredding rye straw in between raised beds covered with corn
based mulch. Mulch provides weed control and protects the soil
© Jean-Paul Courtens 2010
Row covers to provide for insect and late frost protection.
Crops generally mature two weeks earlier with this method
Page 16
These families are grouped into four different groups in one rotation:

Sweet-corn (25%)

Plasti-culture (25%)
tomatoes, peppers, eggplant
summer squash, cucumbers, melons
Onions

Mixed veggies (40%)
Two row crops like early broccoli, bok-choi, Chinese cabbage, collards, early kale,
leeks, fennel.
Three row crops like summer cabbage, mei-ching-choi, sugarsnap peas, summer
beets, chard and broccoli rabe for bunching, tatsoi for greens, basil, parsley, head
lettuce, and baby turnips
Five or nine row crops like spinach, salad greens, braising mix, baby carrots, chard
and broccoli rabe for leaves, tatsoi for salad, and herbs like cilantro and dill.

Snap beans (10%)
And in a different rotation for the Storage Crops:

potatoes (15%)

winter-squash (15%)

beets, carrots, parsnips, celeriac (20%)

green and red cabbage, rutabaga, kale, collards, cauliflower, fall broccoli (40%)

Sweet potatoes (10%)
All crops incl. sweet corn are planted in blocks 50 feet wide
allowing for good access with harvesting, irrigation and pest
control. European Corn borer is controlled with parasitic wasp
and the application of entrust with a one sided boom sprayer.
© Jean-Paul Courtens 2010
kale, broccoli and cauliflower planted after a crop of bell
beans. No other fertilizer is applied to produce 4 lbs heads of
cauliflower. Imported cabbage worm is controlled with Dipel
DF
Page 17
Record keeping for crop rotations in MS Excel:
Steps for Creating a DATA sheet.
1. To name the sheet go to Format at the top of the page and click on Sheet. Then click on
Rename. Type in the name of your field and DATA.
2. Then create a table for each section of your field. Each row in the table will represent a
bed in the section.
a. At the top of the table create your Data headings. We use SECTION, BED,
CURRENT PLANTING, DATE, PREVIOUS PLANTING (in case of multiple
plantings in one season) COVER CROP, AND DATE.
b. In the table you can use color to separate the data to make reading easier if you
prefer.
c. In the DATE columns the cells need to be formatted for the date. Go to Format
at the top of the page. Click on Cells. Then click on the tab for Number. The
choose Date from the list. Pick the format for how you want the dates to appear.
3. Highlight the whole table and then to copy use Control C. Then paste a table for each of
your sections in the field by pushing Control V.
4. Now the tables are set up for recording your crop data.
Sample data sheet:
Roxbury Farm
HOME
MAP
2006
Lindenwald Field
SECTION
BED
CURRENT
PLANTING
DATE
SECOND
PLANTING
DATE
COVER
CROP
1
1
1st Peas
26-Mar
Lettuce 15
23-Jul
none
6 bu
2
1st Peas
26-Mar
Lettuce 15
23-Jul
none
48
3
1st Peas
26-Mar
Dill, Cilantro 16
30-Jul
none
4
1st Peas
26-Mar
Lettuce 17
6-Aug
none
5
2nd Peas
2-Apr
Lettuce 17
6-Aug
none
6
2nd Peas
2-Apr
Lettuce 16
30-Jul
none
7
2nd Peas
2-Apr
Lettuce 16
30-Jul
none
8
2nd Peas
2-Apr
Spinach 16, 17
30-Jul
none
CURRENT
PLANTING
SECTION
BED
2
1
Chard
6 bu
2
Scallion 1
48
3
Chard 2
4
Scallion 2
5
6
DATE
SECOND
PLANTING
DATE
COVER
CROP
9-Apr
Spinach 21
3-Sep
none
9-Apr
Spinach 21
3-Sep
none
23-Apr
Lettuce 21
3-Sep
none
23-Apr
Lettuce 21
3-Sep
none
3rd Peas
9-Apr
Lettuce 21
3-Sep
none
3rd Peas
9-Apr
Lettuce 20
27-Aug
none
7
3rd Peas
9-Apr
Lettuce 20
27-Aug
none
8
3rd Peas
9-Apr
Lettuce 20
27-Aug
none
© Jean-Paul Courtens 2010
DATE
DATE
Page 18
Steps for Creating Maps
1. To name this sheet go to Format at the top of the page. Click on Sheets and then
Rename. Type in the name of your field and MAP.
2. Go to Tools at top of page & click on Options. Under Options click on the Gridlines box
so that the check mark disappears. Now you will have a blank screen.
3. The width of columns needs to be narrower. Go to Format at top of page & click on
Columns. Then click on Width and type in desired width. I use 3.
4. Create your first section.
a. Each column represents one bed in the section. To outline the section and each
bed use the Outline box
at the top of the page.
b. First highlight the boxes for the length of the left side of your section. Then click
on the arrow
next to the Outline Box and choose the Left Outline.
c.
Next highlight the boxes for the bottom side.
you have beds per section. Then click on
and choose the Bottom Outline.
Go over as many columns as
arrow next to the Outline Box
d. Then outline the right side & the top.
e. Next to separate the beds in the section highlight each column within the box you
just created and outline one side.
5. Number each bed in the section.
6. Now merge cells and align the text for the data that will be entered later.
a. Highlight 5-6 cells in one bed in your section.
b. Go to Format at the top of the page and click on Cell.
c. Go to the Alignment tab. Then click on the box next to Merge cells and the box
next to Shrink to fit.
d. Then change the alignment of the text to 90 degrees.
e. Highlight the cells you merged and copy them by using Control C.
f. Highlight the cells in the next bed and paste by using Control V. Do this for the
rest of the beds in the section.
1. Now each cell in the section needs to be linked to the data cell they correspond to on
the DATA sheet.
a. Click on your merged cells in the first bed in the section. Then go to the formula
bar at the top of the page and click on the = sign. Then type:
„Field Name DATA‟! Column letter cell name
e.g. „Field DATA‟!D6
then click OK
b. To copy this into the rest of the beds, highlight „Field DATA‟!D6 (not the equal
sign). Then push Control C to copy. Push tab to get to the next bed and go to
the Formula bar and click on the equal sign. Then push Control V and the copied
information should be in the formula bar. Then click OK and copy the information
into the next bed. Repeat for the rest of the beds in the section.
2. Now copy the whole section by highlighting it and pushing Control C. Then paste a
section for each section in your field by pushing Control V.
© Jean-Paul Courtens 2010
Page 19
3. Now you need to change the cell numbers in the formulas to correspond with the
correct cell number on the Data Sheet.
a. Click on the merged cell in the bed. Click on the formula bar at the end of the
information. Delete the incorrect cell number and Column letter if needed and
type in the correct information.
b. Then click Tab and move to the next bed. Repeat for all beds in all sections in
the field.
You can add your field name and include trees, roads, creeks, and other landmarks by filling the
cells with different colors.
Sample Map sheet:
Roxbury Farm
DATA
2006
Section 1
Section 2
1st Peas
2nd Peas
2nd Peas
2nd Peas
2nd Peas
Chard
Scallion 1
Chard 2
Scallion 2
3rd Peas
3rd Peas
3rd Peas
3rd Peas
44.8 bu
1st Peas
5.8 bu/bed
1st Peas
44.8 bu
1st Peas
5.8 bu/bed
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
ROUTE 9H
© Jean-Paul Courtens 2010
Page 20
Use the following rotations as an example:
Year 1
Year 2
Year 3
Year 4
Year 5
Spring
peas/
barley/bell
beans
spring
bare
fallow
oats
potatoes/
wintersquash
rye and
vetch
spring
bare
fallow
Summer
Broccoli/
cauliflower/
kale
Sorghum
Sudan
Forage
Soybean
potatoes/
wintersquash
summer
bare
fallow
carrots,
celeriac,
parsnips
Fall
Broccoli/
cauliflower/
kale
Late
summer
bare fallow
oats
rye and
vetch
oats and
peas
carrots,
celeriac,
parsnips
Here we have a five year rotation in the storage vegetable group. The peas/barley/bell beans fix
the needed nitrogen for the following cole crops which are considered heavy feeders. Summer
weeds are very well controlled in that year but a spring fallow is needed to flush out the spring
weeds for the receding potato crop. Sorghum is used as a bio-fumigant to reduce rhizoctonia and
scab in the potatoes, and black rot in the winter squash. The potatoes and winter squash are
followed with rye and vetch which are harvested for straw to be used in the plasti-culture. A
summer fallow is needed to prepare land for carrots and parsnips. Oats is seeded not until Sept
1to avoid excessive growth.
Year 1
Year 2
Year 3
Year 4
Year 5
year 6
Year 7
Spring
oats, red
and
sweet
clover
red and
sweet
clover
oats and
peas
remains
rye and
vetch
Spring
veggies
spring
bare
fallow
rye and
vetch
Summer
red and
sweet
clover
sweet
corn
plasticulture
summer
bare
fallow
summer
veggies
green
beans
summer
bare
fallow
Fall
red and
sweet
clover
oats and
peas
rye and
vetch
oats and
peas
fall mixed
veggies
rye and
vetch
fall mixed
veggies
Here the ground is prepared to provide sweet corn with the necessary nitrogen to support good
growth. The sweet corn is an excellent crop to precede the plasti-culture crops as sweet corn
does not serve as a host to the many diseases affecting the Solanaceae and cucurbits while
weeds are generally under good control. The following rye and vetch is harvested for straw and a
bare fallow is introduced to clean up the seed bank that generally builds up during a plasti-culture
cycle. The mixed vegetable grown in year 5 are often double cropped as a fine seed bed with
little plant residue is required for optimum seeding and weed control. The following year a crop of
green beans is followed with another crop of rye and vetch. this is again harvested in year 7 for
straw and followed by a summer fallow to create good planting conditions for a seeded crop of fall
vegetables.
© Jean-Paul Courtens 2010
Page 21
Disease problems and efficacy of a Crop Rotation:
disease
Strain
Common name
Rotation
Length
Affected Crop
Alternaria
brassicicola
early blight
yes
4 years
cole crops
Alternaria
cucumerina
leaf blight
yes
4 years
cucurbits
Alternaria
solani
early blight
yes
4 years
tomato, potato
Alternaria
dauci
early blight
yes
4 years
carrots
Ascochyta
rhizoc
wet weather blight
yes
4-6 years
parsnip
Ascochyta
pisi
seedling blight
yes
4-6 years
peas
Botrytis
cinerea
botrytis blight
yes/no
2 years
Bremia
lactuca
downy mildew
yes
2-4 years
lettuce
Cercospora
beticola
leaf spot
yes
5 years
beets
Cladosporium
cucumerinum
Scab
yes
4 years
cucurbits
Clavibacter
michiganensis
bacterial canker
yes
6 years
tomatoes
Colletotrichum
lagenarium
anthracnose
yes
2 years
cucurbits
Colletotrichum
lagenarium
anthracnose
yes
2 years
bean/cucumber
Colletotrichum
coccodes
anthracnose
yes
2 years
tomatoes
Didymella
bryoniae
black rot, gummy
stem blight
yes
3 - 4 years
cucurbits
Erwinia
tracheiphila
bacterial wilt
yes/no
2-4 years
cucurbits
Erwinia
carotovora
potato soft spot
yes
4 years
potatoes
Erwinia
stuarrti
corn stewart's wilt
no
flea beetle
Erysiphe
cichoracearum
powdery mildew
no
airborne
cucurbits
Erysiphe
cruciferarum
powdery mildew
no
airborne
cole crops
Erysiphe
lycopersici
powdery mildew
no
airborne
tomatoes
Erysiphe
pisi
powdery mildew
no
airborne
carrots, parsnips
Erysiphe
heraclei
powdery mildew
no
airborne
beets
Erysiphe
taurica
powdery mildew
no
airborne
solanaceae
Fusarium
oxysporum
fusarium wilt
yes/no
wind/equipment
cucurbits
Hyaloperonospora
parasitica
downy mildew
yes
2-4 years
cole crops
Itersonilia
itersonilia
black canker
yes
4 years
parsnips
Phoma
lingham
black Leg
yes
4 years
cole crops
Phytophthora
capsici
phytophthora blight
yes
4 -5 years
peppers,
cucurbits
Phytophthora
Infestans
late blight
no
freeze/airborne
tomatoes,
potatoes
© Jean-Paul Courtens 2010
many crops
corn
Page 22
Disease problems and efficacy of a Crop Rotation:
disease
Strain
Common name
Plasmodiophora
brassicae
clubroot
Plectosorium
tabacinum
downy mildew
Rotation
Length
Affected Crop
yes
7 years
cole crops
yes/no
4 years
Cucurbits
airborne
Podosphaera
xanthii
powdery Mildew
no
airborne
Cucurbits
Pseudonomas
marginalis
brown interirors
yes
2-4 years
parsnips
Pseudonomas
syringae pv
lachrymans
angular leaf spot
yes
2-4 years
cucurbits
Pseudonomas
syringae
bacterial speck
yes
2-4 years
tomatoes
Pseudoperonospora
cubensis
downey mildew
no
airborne
cucurbits
Puccinia
sorghi
corn rust
no
airborne
damping off, root
rot
yes
?
seedlings, many
hosts
root rot, belly
rot,
yes
10 years
cabbage, lettuce,
Pythium
Rhizoctonia
solani
black rot
potato, tomato
Rhizomonas
suberifaciens
corky root
yes
2 years
lettuce
Sclerotinia
sclerotiorum
white mold
yes
5-10 years
beans
Sclerotinia
sclerotiorum
watery soft rot
yes
5-10 years
cabbage
Sclerotinia
sclerotiorum
drop
yes
5-10 years
lettuce
Sclerotinia
sclerotiorum
stem rot
yes
5-10 years
tomato potato
Septoria
lycopersici
septoria Leaf
spot
yes
4 years
tomato
Septoria
lactucae
blight
yes
4 years
lettuce
Stemphylium
oleraccea
stemphilium leaf
spot
yes
4 years
spinach, clovers
Streptomyces
ipomoea
soil rot (pox)
yes
6 years
sweet potato
Ustilago
maydis
corn Smut
no
airborne
Verticillium
albo-atrum
verticillium wilt
yes
13 years
eggplant, many
hosts
Xanthomonas
campestris pv.
phaseoli
bacterial leaf
spot
yes
2-4 years
lettuce,peas
Xanthomonas
campestris pv.
vesicatoria
bacterial leaf
spot
yes
2-4 years
peppers,tomatoes
Xanthomonas
campestris pv.
campestris
black rot
yes
2-4 years
cole crops
© Jean-Paul Courtens 2010
Page 23
Insect Problems and efficacy of Crop Rotation:
Insect Common name
Rotation
Length
Affected Crop
Notes
aphid, cabbage
limited
1 year
cole crops
limit on nitrogen fertilizer
aphid, corn leaf
limited
1 year
sweet corn
limit on nitrogen fertilizer
aphid, green peach
limited
1 year
many crops
limit on nitrogen fertilizer
aphid, melon
limited
1 year
cucurbits, pepper, eggplant
limit on nitrogen fertilizer
aphid, pea
limited
1 year
peas, favabeans, lentils
overwinters on clover
aphid, potato
limited
1 year
potato, many host plants
limit on nitrogen fertilizer
cole crops
migrates from south
armyworm, common
no
bean leaf beetle
yes
1 year
soybean
cabbage root fly
yes
1 year
cabbage, broccoli
cabbage looper
no
1 year
cole crops
carrot weevil
yes
2 years
carrots
carrot rust fly
yes
1 year
carrots
plant upwind
Colorado potato beetle
yes
1 year
potato, eggplant
plant succession far away
corn ear worm
no
1 year
sweet corn
migrates from south
cross striped cabbage worm
yes
1 year
cole crops
plow under plant debris
cucumber beetle spotted
yes
1 year
cucurbits
overwinter at edge of field
cucumber beetle striped
yes
1 year
cucurbits
use trap crops
cutworm black
no
many plants
fall plowing, weed control
cutworm variegated
no
many plants
both cutworms are migratory
diamond back moth
yes
1 year
cole crops
plow under plant debris
European corn borer
yes
1 year
sweet corn, peppers
shred stalks in fall, plow under
fall armyworm
no
1 year
sweet corn
migrates from south
flea beetle Corn
yes
1 year
sweet corn
plant succession far away
flea beetle crucifer
yes
1 year
cole crops
plant succession far away
flea beetle eggplant
yes
1 year
eggplant, potato
plant succession far away
fungus gnats
no
potting soil, many hosts
hygiene in greenhouse
cole crops
can fly large distances
imported cabbage worm
© Jean-Paul Courtens 2010
limited
1 year
migrates from south
Page 24
Insect Problems and efficacy of Crop Rotation:
Insect Common name
Rotation
Length
Affected Crop
Notes
Japanese beetle
no
1 year
basil, corn,
can fly large distances
leaf miners
yes
1 year
beets, chard, spinach
weed control
leafhopper Aster
no
1 year
lettuce
windblown from the
south
leafhopper potato
no
1 year
potato, lettuce, snap
beans
migrates from south
maggot cabbage
yes
1 year
cole crops
can fly large distances
maggot onion
yes
1 year
alliums
can fly large distances
maggot pepper
yes
1 year
peppers
can fly large distances
maggot seed corn
yes
1 year
sweet corn
can fly large distances
Mexican bean beetle
yes
1 year
snap beans
plow under plant debris
mite, two spotted spider
limited
1 year
tomato, pepper, melons
many host plants
sap beetle
limited
1 year
corn, melons
squash bug
yes
1 year
summer squash, cucurbits
squash vine borer
yes
1 year
cucurbits
stalk borer common
yes
1 year
tomato
stink bug
limited
1 year
many plants
overwinters in sod and
hedgerows
tarnished plant bug
limited
1 year
strawberry, lettuce
many hosts, weed
control
thrips onion
limited
1 year
alliums, colecrops
manage hayfields
tomato hornworm
limited
1 year
tomato
can fly large distances
whitefly
yes
1 year
lettuce, tomatoes
hygiene
wireworm
yes
many crops
when issue reduce
fresh OM input
© Jean-Paul Courtens 2010
plant succession far
away
Page 25
D. Biodynamic preparations:
Within the management practices of the biodynamic preparations we can distinguish two different
types of applications.
1. The compost preparations.
The use of biodynamic preparations in the compost allows plants to become healthier, not
only in the field but also more nutritious as food or feed. When you make compost, the
original materials (which can be manure, woodchips, horse bedding, plant waste etc.)
transform into something completely new. The original organic materials disappear to create
a complete new substance. The original ingredients and the management of the pile
determine the quality of the compost. In organic certification frequent turning is required to
ensure that harmful pathogens are adequately destroyed. The disadvantage of this is similar
to frequent tillage of the soil; we tend to burn up the pile creating greater losses of organic
matter than when we allow it to break down a more natural way.
The compost pile is an opportunity to manage the decomposition processes on the farm.
Organic materials are constantly consumed by different organisms at every different state of
decomposition. Certain types of bacteria, fungi, actinomycetes, nematodes, mites, snails,
slugs, earthworms, millipedes, etc. are the primary consumers of the organic materials in the
compost pile. That is because they live off the manure, grass clippings, leaves, wood chips
etc. But as our primary consumer group gets established they quickly become the food
source of another group of organisms. Springtails, certain mites, beetles, nematodes,
protozoa, rotifera, and soil flatworms live off the first group and are called the secondary
consumers. Finally this group gets eaten as well by centipedes, predatory mites; rove
beetles, fomicid ants, and carabid beetles which we call the tertiary consumers. The density
of animal life in the compost pile is like a high-rise in the city. This complexity of organisms
requires management just like any other animal we keep on the farm.
The decomposition processes are like other
digestive processes. Digestive systems in
higher organism are regulated by our
organs.
In biodynamic agriculture the
preparations help regulate those processes
in the compost pile. The compost
preparations can be compared to organs or
bodily functions that regulate the digestive
processes in the compost. Each preparation
provides a different quality and Steiner
chose from a variety of plants with balancing
qualities.
These herbs combined with
inserting the compost preparations using the handle of a rake
certain animal parts are first fermented and
"charged" in a particular way to be added in minute quantities to the pile. They work by
radiating out a positive channeling of forces that support the decomposition of the organic
materials. In general the preps organize the life forces and are sometimes referred to as bioorganizers. For every ton of organic material a pinch of chamomile, yarrow, oak bark and
yarrow is inserted at all four corners of the pile, while nettle is placed in the middle. The
handle of a rake can be used to create a tube like opening that allows us to insert the
preparation into the pile. In the middle we place the nettle (which can be used more
abundantly), while the valerian is mixed with lukewarm water and sprayed on the surface of
the pile.
© Jean-Paul Courtens 2010
Page 26
There are six different compost preparations:
For a more thorough insight the reader is referred to the original source which is Planetary
Forces and Life Processes by Bernard Lievegoed PhD MD
The
chamomile
preparation
is
associated with the planet Mercury.
Mercury stands for mobility, agility, and
sensitive chaos; a movement without
direction but willing to flow into every crevice
available while taking up its form. Bernard
Lievegoed compares the planetary qualities
the preparations bring to the farm to the
planetary qualities in people. . People can
be described as being endowed with certain
planetary qualities. For example in people,
Mercury works through the lymphatic system and lymph vessels, and is related to humor.
The comedian draws from what can be considered mercurial qualities; by having the ability to
make funny faces, to have wit and a sense of humor, and to allow things to keep moving
draws from mercurial qualities. Good sales persons or politicians show these qualities in
their ability to be realistic and to rapidly adapt to a new situation. In its desperation those
qualities can become deceitful, and here we see the relationship of Mercury to Hermes, the
Greek mercurial God of traders and thieves, who are alike in the way that they remain all
earthly possessions in motion.
Chamomile preparation is made of the dried chamomile flowers (Matricaria chamomilla or
Matricaria recutita). Most seed suppliers sell the common chamomile which is also called
German Chamomile and available from sources like Environmental Seed Producers in
Lompoc, California. According to the USDA database German or common Chamomile grows
wild in the Northeast. When we use purchased in instead of cultivated chamomile, we cannot
be assured that it is of the common type. The question is also in how fresh the supply is and
how vibrant the flowers are. When grown on the farm, chamomile needs to be harvested on
a daily basis with a comb (available at Johnny Selected Seeds) to ensure the use of young
flowers heads. The flowers need to be dried as quickly as possible without losing any of their
aromas.
The finished preparation is a substance that works in the processes of potash and calcium in
the soil, while in the treated manure it creates greater stability of its nitrogen content. Applied
compost helps plants to better take up potassium and calcium. Crops grown on treated land
are healthier and more nutritious with the help of the chamomile preparation.
In the fall before we use the flowers, we will need to briefly soak them in lukewarm
chamomile tea. This substance is then placed in freshly obtained intestines of a cow. A
freshly slaughtered cow is recommended. We avoid using any intestine from a cow that was
recently fed grain. If there is a lot of food stuff in the intestines we carefully flush them out
with water. Also here we do not know exactly how the decomposition process works but it
works better when we work with fresh intestines. We can choose to first blow the intestines
up with a straw (like we do with the stag bladder) which makes stuffing with the flowers
afterwards easier. The stuffed, so-called sausages are then placed in the soil and kept there
over the winter in a place where snowdrift collects. Always bury the preparation in deep soil
like we can find in a fertile garden.
The dandelion preparation is associated with Jupiter. Jupiter is the sculptor of the
world and stands for beauty, wisdom, and the ability to have oversight. Philosophers are
endowed with strong Jupiter qualities. While a person endowed with Mercurial qualities lives
© Jean-Paul Courtens 2010
Page 27
in the valley occupied with all infinite details,
a person with Jupiter qualities would be on
a hilltop having the best view of the world.
In our body we recognize Jupiter by the
roundness of our skull or the ball shaped
joints of the shoulder, knee, or hip. On the
other hand Jupiter is also associated with
surface tension that allows our muscles to
function. In the plant world this surface
tension is facilitated through the silica
processes.
The dandelion preparation is working
through the compost by endowing the soil
with wisdom. The thought is that all the positive influences from stream, pond, forest,
meadow and fields become available to the plant through the soil amended with compost
treated with the dandelion preparation. The idea is that those soils will better be able to
absorb cosmic forces needed to vitalize the farm as a living organism.
The preparation is made from the dried dandelion (Taraxacum officinale) flowers. The
flowers are picked in the morning. Only the flowers that have not yet fully opened are useful.
When they are dried, the flowers that are too mature would enter the seed stage. When we
make this preparation in the fall, we start by soaking the flowers in lukewarm dandelion tea.
The next step is to place this substance in little bags that we form out of the mesentery of a
cow. The mesentery should be free of fat since that would inhibit proper transformation once
it is placed in the soil. Also, when the bags are too large, there is a chance that the
substance will turn into silage. A good size is about the size of a tennis ball or of a small flat
sized package. These pockets are then buried like the chamomile preparation.
The yarrow preparation is associated with
Venus.
Venus stands for care and
reception. People with Venus qualities
have good parenting skills, and a good
ability to nurture and host. People with
strong Venus qualities are good listeners,
and are able to create a space so others
can fill it. Venus allows the conversation to
take place. Think of the ability of a chalice
to hold wine; it can only do so because of its
hollow shape and it is open to what comes
from above. Think of Venus as the hollow
body of a violin that creates the resonance
of the sound created by the friction between
the strings and the bow.
The yarrow preparation Should give the treated manure the ability to vitalize the soil. It
should give the earth the qualities to absorb minute quantities of trace minerals out of space.
Steiner mentions in the "Agriculture Course" that the mere presence of yarrow will have
positive influences on a farm. The yarrow preparation is involved in the processes where
potassium is involved in stem formation and sturdiness.
The preparation is made in the early summer with dried yarrow (Achillea millefolium) flowers
that are briefly soaked in lukewarm yarrow tea. Yarrow flowers are harvested over the
previous summer when the flowers are in full bloom. The soaked dried flowers are placed in
© Jean-Paul Courtens 2010
Page 28
the bladder of a stag and hung on the south side of a barn. The bladder can be enlarged by
being inflated and tied down to maintain its shape. In the fall the bags are brought down and
are buried over the winter months in fertile topsoil.
The nettle preparation is associated
with Mars.
Mars stands for
forcefulness and it is no surprise that nettle
helps plants in the processes of growth.
Mars represents growth especially in the
sprouting buds. It is best described as
movement with clear and concise purpose.
Think of an athlete throwing a spear or a
musician drawing the hairs of a bow across
the strings of a violin. It is in the friction
between the two that sound is created.
Mars becomes visible in the resistance of
its force. The air meets this resistance on our vocal cords, the spear in the target, and the
hairs of the bow on the strings of a violin. People with strong Mars qualities are poor
caretakers often allowing something to be destroyed in order to make space for their fertile
and creative ideas and initiatives. While Mars speaks, Venus listens; together creating a
conversation. In many different cultures these two symbols have been representative of the
male and female element in nature. An ancient symbol for Venus is V, while Mars is
symbolized with Λ.
The nettle preparation has a strong relationship to the iron processes in the plant and its
ability to form proteins. The soil treated with nettle preparation becomes individualized to the
crops we intend to grow with higher nutrition values. Although it is not considered a
biodynamic practice, some people use the nettle fresh as a compost tea with good result.
The nettle‟s properties is said to increase growth when applied as a foliar spray. I personally
do not have any result with this but
Nettle preparation is the easiest to make and can also be used as a foliar spray. The nettle
(Urtica dioica) is harvested before the flowers go to seed. It is then directly placed in the
earth, but not in direct contact with it. We place a layer of peat moss between the nettle and
the moist earth. It is left there for a full season (summer and winter), and is then dug up and
used as a preparation in the compost pile. Nettle does not need an animal organ but is often
placed in a ceramic pipe to help us locate the finished preparation. Often when the nettle is
buried with some peat moss it takes a lot of effort to separate the garden soil from the
preparation. As with all the preparations we need to ensure that plant roots cannot grow into
the preparations so we prefer open garden soil over a perennial plant garden.
The oak bark preparation is
associated with the moon. We can
think here of the moon‟s ability to reflect
the sun. When we consider moon quality
we think of the ability to adjust by means
of reflection.
Moon forces work in
reproduction and genetics and find their
boundaries in our skin. Some actors are
blessed with strong moon qualities as
moon qualities determine our skin, our
ability to imitate, and our sexual attraction
to each other. While the moon represents
growth (almost without boundaries) it also
dampens growth by creating better
boundaries. Just as our body is contained
© Jean-Paul Courtens 2010
Page 29
by our skin, moon forces are retained in nature by the other aspect of those same moon
forces in its quality to reflect and differentiate.
Oak bark preparation works on the farm by containing healthy growth and by giving it
boundaries. This preparation will, if made properly, give the compost a disease suppressing
quality. Oak bark preparation works in the calcium processes of the plants. Calcium in the
plant is found in the cell walls and insufficient amounts will lead to poor resistance to
diseases. While bark in general forms a protective layer on the tree to protect the cambium,
the oak bark is high in calcium.
Oak bark (from Quercus robur - English oak in Europe, Quercus alba -white oak, or Quercus
bicolor-swamp oak in the US) preparation is made of finely ground-up oak bark that is put
inside the skull of a freshly slaughtered cow or other bovine animal. The oak bark is taken
from a white oak and only the living part of the bark (which lies directly underneath the dead
part) is harvested. The harvested oak bark is finely ground up (an old coffee grinder works
great). When we use a fresh skull we need to remove all flesh and other living parts. Great
care is taken when the brains are removed to make place for the oak bark. You can use a
long spoon or flush them out with a hose. After the oak bark is inserted into the cavity we
cover the hole up with a piece of bone making sure we do not seal off the opening. The skull
is then placed in moving water that preferably has a somewhat mucky nature. We can
choose to seal off the foramen magnum with clay as well as bone so that the ground oak bark
is not washed out by the moving water. There are many other, smaller foramina, however, so
with this method the water can still get in contact with the water. In the spring the skull is
taken up and the composted oak-bark removed. The transformed matter will be dark brown
to black and will have little smell left.
The last is the valerian preparation which is
associated with Saturn.
Scientists and
accountants are endowed with strong Saturnal
qualities as they tend to work in the past, although
this is only partly how Saturn works in us. It is about
incarnating the spirit into substance. Saturn stands
both for death and resurrection. In our body Saturn is
represented by our skeleton. Our bones are formed
through a process of crystallization, representing
dead tissue, while its core, the bone marrow creates
new life in the form of blood.
The Valerian
preparation helps the soil absorbing those cosmic
forces allowing the plant to express their archetype.
The valerian acts like a skin and contributes an
element of warmth to the pile. In the spring I take
advantage of this ability by spraying the valerian
tincture on tender plants to protect them from early
morning frost.
Here we use the fresh flowers of Valeriana officinalis
as the juice is pressed out. The timing is when the
plants are in full bloom (August/September). You can
best use a press to squeeze the juice out of the flowers as we want to end up with a clear
liquid. There are two variations available: one is fermented, which I prefer, and the other is
bottled up the way it comes out of the press. The smell of the fermented valerian is
absolutely wonderful. This preparation is like the nettle made without an animal component.
The finished tincture is diluted in lukewarm water, stirred vigorously and sprayed onto the
compost pile.
© Jean-Paul Courtens 2010
Page 30
2. The field sprays:
The
horn-manure
and
horn-silica
preparations are both made with the horn
of a cow.
The field sprays are associated with the
sun each in their own particular way. While
the horn manure works through root
system and organic matter (organic matter
and roots is in effect stored sunlight ), the
horn silica works with the direct influence of
light from the sun by improving
photosynthesis.
Great care is taken in what location the
preparations are buried. The ideal location is where snow usually accumulates. The
processes in a fertile soil covered deeply under a snow cover allow for the best conditions for
proper transformation.
In the fall we make the horn-manure preparation.
Horn manure directly influences the way
organic matter is transformed in the soil. Its
positive influences are similar to what organic
matter and phosphorus does to root
development of our crops. In general, we
notice that horn manure works on
germination, root development, and growth.
Also called preparation 500, it has shown to
increase rooting depth of both cash and
cover crops while providing better conversion
from raw organic matter to humus (building
long lasting soil fertility).
Here we prefer to use cow manure and we
select cow pies with enough form whereby the shape of the intestines are somewhat visible.
Avoid using pies that have too much shape like that of sheep-manure. We stuff the manure
into the horns and then bury them in the ground with the points of the horns sticking up to
avoid rainwater running in. In the month of May this preparation is dug up. The substance in
the horns has by then become odorless. If there is a smell to it or if it still looks like manure,
then you know that it has not been properly transformed. Before this preparation is applied to
the fields as a spray, we have to dilute it in lukewarm water. About a tennis-ball size quantity
per thirty gallons of water is sufficient. This is stirred vigorously in one direction until a vortex
is formed, and then the direction is reversed and stirred in the opposite direction to create
another vortex, etc. The total time of stirring is one hour. The solution will now start smelling
again, not like manure, but definitely alive. For filtering the liquid I found paint bags to work
best. Filtering avoids wasting time in the field cleaning spray-nozzles. Our 3.5 gallon
backpack sprayer covers about one acre. This preparation is sprayed directly on the soil,
previously to tillage in spring or in the fall on hayfields.
© Jean-Paul Courtens 2010
Page 31
The Horn-Silica preparation makes use of
a cow-horn again filled with finely ground
Silica. This is then placed in the ground during
the summer months. A much smaller quantity
than the horn manure, no more than a pea-size
amount, is stirred vigorously in 30 gallons of
water for one hour. This solution is sprayed
directly on the plants. The Horn Silica has a
strong connection to the light and warmth forces
of the summer. Its positive influences are
similar to what the summer sun contributes to
the plants. It slows down growth but increases
the overall plant mass. Plants treated with this
preparation are shown to have better taste and keeping qualities. All preparations including
horn-manure should be stored in peat moss in a dark, cool and damp place, with the
exception of horn-Silica which is left in a glass jar on a windowsill.
4.
Soil Chemistry
To properly discuss the nutritional needs of plants we need to realize that of all the substances
that are taken up by plants, minerals make up the smallest, while carbon and hydrogen and
oxygen make up the greatest fraction. Carbon-dioxide is taken up by way of diffusion out of the
air by the leaves stomata‟s while water (hydrogen and oxygen) and minerals are taken up by the
roots out of the soil. Water is absorbed by means of osmosis. The mineral solutions in the roots
have a higher concentration of salts than the soil which allows the plant to absorb soil moisture
with a slightly lower level of minerals. Consequently, when soluble fertilizer is available in high
concentrations around the roots, the plants are
unable to absorb water.
High salt content can
cause the roots of a plant to “burn”. In extreme
situations it will cause the plants to die. We have
observed this at times in the greenhouse when the
potting soil had a high concentration of soluble salts
(not just sodium).
In biodynamics we make a distinction between plant
nutrition that is cosmic and plant nutrition that is
terrestrial. Minerals come from the earth while the
sun and other cosmic bodies give the plant the
sun solar coronal mass ejection
strength to absorb water, carbon and minerals. The
energy from the sun is cosmic and its forces that
are partly visible as light have an important influence on the quality of the crops we raise. All
living organisms absorb the sun‟s energy either directly or indirectly. Silica plays a facilitating role
between the sun‟s energy and all forms of life on earth. It is not a coincidence that we find silica
in the periphery of all things; in the xylem of the cell walls, in skin and hair and Silicon makes up
of 28% of the crust of the earth. Silica can be considered the mineral that is the medium between
the cosmic and the terrestrial. While it is very much part of the earth, it does not interact much
with its environment. It does not get involved chemically, as it is neither positive nor negatively
charged. It cannot hold nutrients and is considered to be merely an aspect of the soil as an
aggregate. It is not difficult to accept that some people have come to believe that silica is merely
a medium that contributes porosity to hold air and water for plants to grow in.
The challenge as a farmer is to balance the energy of the terrestrial and the cosmic. The two are
a team as their combined energy provides for healthy plant growth. Once minerals are released
in a soluble form the plant has less ability to differentiate. In biodynamics we recognize the need
© Jean-Paul Courtens 2010
Page 32
for proper nutrition, but the addition of fertilizer is seen as a temporary remedy. In a biologically
healthy soil, nutrients are carefully recycled and a good portion of crops in the rotation are
effective carbon and nitrogen fixers, while others crops are selected to retrieve minerals from the
subsoil. As microorganisms play a large role in helping plants to absorb minerals, a biodynamic
farmer hesitates in upsetting the delicate balance that would destroy these ecosystems.
Reduced tillage and the recycling of manure are important components in sustaining the soil
ecology and contributes to the aim of reduced inputs.
Plant nutrition can be viewed from many different perspectives and the different approaches can
appear contradictive to each other creating more confusion than clarity. At that point it will be
good to remember one interesting point; while malnutrition causes many problems and deaths in
the developing world; ample nutrition has become the main cause of death in the rich industrial
world. Lawrence D. Hills (the renowned British organic gardener) is quoted by saying: "We are
starving to death on a full stomach ". The modern nutritional approach tends to focus on the
individual components that only combined provide us with nourishment.
The following
information needs to be placed as one aspect that combined with a holistic approach make for
good soil, plant and animal health.
There are many different approaches when it comes to determining the correct or optimum
amount of nutrients in the soil. The first approach is from Justus von Liebig who claimed that:
“The yield of a crop is determined by the growth factor of the least available nutrient”. It is called
“the law of the minimum” as yield can only be improved when the nutrients that are least available
are increased. It implies that yield losses are caused by mineral deficiencies. Von Liebig‟s
approach is like fixing the weakest link in the chain.
Another approach is from Mitscherlich who formulated his law of growth effects this way: “The
yield of a crop is determined by every factor that is not optimum. The further a factor is removed
from its optimum, the greater its influence”. This means that nutrients can lead to yield losses
when their availability is either excessive or deficient to plants.
The well known American soil scientist William Albrecht believed that the available nutrients
should be optimized based on their percentage of the total saturated base. In other words to
achieve adequate plant nutrition an appropriate balance of nutrients in the soil is necessary. In
his approach calcium should take up 65 -70% of the available cations, magnesium 10%, and
potassium 3% - 5%. His studies showed that in areas west of the Mississippi river where rainfall
is less than 25 inches per year, minerals
like calcium are in abundant supply
creating conditions for good grass and
legume development. As grasses and
legumes that are rich in protein are the
source for muscle development of
ruminants,
he
explained
the
rich
development of the bison on the prairies is
due to the suitable chemical composition of
the soils. We have seen that optimum
calcium conditions allow for better
development of the legumes like clover
and alfalfa.
As a good stand reduces
weed development the Albrecht approach
has become a tool to eliminate weeds in
Spreading gypsum to increase Ca levels
our cover crops. We have also learned to
cut back on compost to avoid build up of potassium which can contribute to excessive weed
development (galansoga, chickweed, and purslane), while we are aware that an excess of
calcium can result in making nutrients unavailable.
© Jean-Paul Courtens 2010
Page 33
Another approach is at times being credited to Mitscherlich. This is the most widely used
methodology which I believe should be credited to farm economists instead of soil scientists.
Here it is recognized that “the increase of a growth effect does not have an even relation to yield
and therefore return”. In other words each extra bag of fertilizer used produces less of a return
on the expense. This phenomenon is therefore called the law of the diminishing returns. The
widespread ecological problems of agriculture are due to this approach as fertilizer has been a
subsidized product and farm economists base the cost of fertilizer on the cost of fertilizer to the
farmer. Once the true cost of runoff and pollution is factored in we will realize that the increased
yield of crops comes at a very high price. As organic farmers we need to rely more on a healthy
soil to produce abundant crops so a diminishing return is reached at far lower levels.
Soils with a high natural fertility reach this diminishing return at far lower application rates
compared to poorer soils. Sandy soils low in organic matter is usually low in nutrients and will
require more fertilizer to obtain a satisfying yield.
Nevertheless no matter what your approach is, the export of minerals and other nutrients from
your farm needs to be replaced. Most of us are faced with a serious deficit of organic matter, and
nutrients as the previous farmer depleted the land with poor farming practices. In this case we
need to import nutrients (including carbon) into our farm to create the proper conditions for a farm
as a healthy organism.
Nutrient removal by crops
N
P
K
Vegetable crop
Asparagus
Beans at 5,000 lbs per acre
Beets
Broccoli at 10 M lbs/acre
Brussels Sprouts
Carrots at 30M/acre
Cantaloupe at 22,5M/acre
Celery at 50M./acre
Lettuce at 20M/acre
Onion at 40M/acre
Peas at 4M/acre
Pepper at 22,5M/acre
Spinach at 20M/acre
Sweet corn at 13M./acre
Sweet Potato at 30M/acre
Potato at 40M/acre
Tomato at 60M/acre
Averages
11
3
6
170
16
100
140
14
140
165
10
210
240
30
235
145
25
345
155
27
155
195
50
425
95
12
170
145
25
155
170
22
80
140
12
140
100
12
100
155
20
105
140
20
200
165
30
225
180
21
280
148
18
187
Adapted from Knott‟s Handbook for vegetable
growers
The above graph shows the complete nutrient removal of all the plant parts. What we need to
realize here is that depending on the crop certain parts esp. the roots are left in the field. When
© Jean-Paul Courtens 2010
Page 34
we harvest potatoes we leave the leaves, when we harvest peppers we leave the whole plant.
Generally speaking, the roots tie up a lot of phosphorus, the stems and leaves tie up a lot of
potassium while phosphorus is removed from the field when we harvest the seed.
Applications of minerals and organic matter can:




Reduce the incidence of deficiencies
Provide conditions for optimum plant development and increase plant health
Improve structural and biological fertility
Enhance the nutritional value of crops
The assessment of the need for mineral or organic fertilizer is based on three factors:
 The soil test (chemical analysis)
 The observation of an excess or deficit of particular nutrients in our crops
 The experience of the farmer
It is important to do annual testing of your soils to make sure the right amount of macro and trace
minerals are available to the crops. When crops show deficiencies we make a distinction
between an absolute or sometimes called primary lack of nutrients or a conditional or sometimes
called secondary lack of nutrients. In the second situation the nutrients are in the soil but are not
available due to a low pH, poor soil structure, drainage et cetera.
A soil test will give
some indication of the
state of your soil. But
besides giving accurate
numbers for its pH and
OM, It does not give a
good prediction of what
yields to expect in an
organic system. I have
seen many instances
where good soil health
(good structure, good
biological diversity, and
good physical qualities)
are the overriding factors
regarding yield.
Organic farmers have to
FERTILIZER RATES FOR VEGETABLES IN NEW YORK (Cornell Cooperative
Extension 1994)
Beans
Beets
Broccoli
Brussels Sprouts
Cabbage
Carrot
Cauliflower
Celery
Cucumber
Eggplant
Endive
Lettuce
Muskmelon
Onion
Parsnip
Pea
Pepper
Potato
Pumpkin
Radish
Rhubarb
Rutabaga
Spinach
Squash Summer
Squash Winter
Sweet corn
Tomato
Turnip
Watermelon
Nitrogen
30-40
150-175
120-150
120-150
120-150
120-150
120-150
180
120-140
130
100-130
100-130
120-140
100-110
120-150
40-50
130
150
120-140
60
50-80
130
130
120-140
120-140
120-140
130
130
120-140
Phosphorus
0-160
0-100
0-200
0-160
0-160
0-160
0-160
0-200
0-160
0-200
0-160
0-160
0-160
0-200
0-160
0-120
0-200
120-300
0-160
0-125
0-160
0-125
50-170
0-160
0-160
0-160
0-200
0-125
0-160
Potassium
0-80
50-400
0-200
0-200
0-200
0-200
0-200
60-300
0-160
0-200
0-200
0-200
0-160
0-200
0-160
0-160
0-200
50-300
0-160
0-200
0-200
0-200
0-200
0-160
0-160
0-160
0-240
0-200
0-160
realize that they depend
greatly on the breakdown
of organic matter for
plant nutrition. Minerals
in compost are tied up
and
their
presence
shows only partly up in a
soil test. But over time
those minerals will be
released by virtue of
mineralization. Organic
farmers rely on improved
soil structure to increase
the yield of their crops. They need to learn to take lab test recommendations with a grain of salt
and the decision to add amendments should be based on a combination of soil tests and field
observations coupled with his or her experience as a farmer.
© Jean-Paul Courtens 2010
Page 35
Cation Exchange Capacity:
The classic theory is that minerals can only be absorbed by plants when they are in solution of
water. There is sufficient evidence that plant roots absorb organic molecules. I do not have
sufficient information on the latter and the following is based on the following hypothesis:
Dissolved minerals fall apart in two electrically charged components called
+1
+1
+2
+2
1) basic cations, like hydrogen (H ), ammonia (NH4 ), calcium (Ca ), magnesium (Mg ),
+1
+1
potassium (K ) but also sodium (Na ).
2) acidic cations also called anions), like, nitrate (NO3-), phosphoric acid (H2PO4-), sulfate (SO4-2),
but also aluminum Al3- and chlorine (Cl-).
Potassium, calcium, and magnesium in solution have a positive charge, while nitrate, aluminum,
sulfate, chlorine and phosphorus have a negative charge. As minerals are available through the
+2
process of osmosis, exchange of ions has to take place. In soluble form Calcium is Ca , a cation
+1
that possesses two positive ions. For the plants to take up calcium, two hydrogen (H ) cations
+2
need to be released from the plant and replaced for the Ca cations. When an acidic cation
(anion) like NO3- is absorbed by plants an equal amount of HCO3 needs to be released.
Respiration of the roots produces carbon dioxide (CO2). Some of the CO2 will form a connection
with water creating hydrogen carbonate (H2CO3). In solution this falls apart in the basic cation
+1
hydrogen H and the acidic cation hydro carbonic acid HCO3 . As a result the area around the
root contains both the necessary basic cations and acidic cation necessary for mineral uptake for
the plants.
Cation exchange capacity (CEC) is a measure of a soil‟s capacity to retain and release nutrients
such as potassium, calcium, magnesium and sodium. Soils with high clay or organic matter tend
to have a high CEC value. In order to understand CEC we can imagine the soil particles as
having “parking spots” for basic material. Parking spots in this picture are negatively charged
allowing a basic material (in this picture “a car”) to be absorbed. Soils high in humus and clay
have a negative charge so are able to provide a lot of “parking spaces” for positively charged
(basic) cations like calcium, potassium and magnesium. Soil CEC is relatively constant over time
although there are reports from growers that were able to dramatically improve the CEC value
with a single application of lake weeds at a rate of 60 tons to the acre.
Base saturation is the percentage of the CEC occupied by each of the basic cations (Ca, Mg, Ca,
and K). In other words what percentage of “parking spots” is occupied by what basic material? If
calcium has a base saturation value of 70% and magnesium has a base saturation value of 12%
then calcium occupies 70% of the total exchange sites (CEC) and magnesium occupies 12% of
the total exchange sites (CEC). When plants absorb these minerals a hydrogen ion is released
from the roots of the plant occupying the “parking space” for the time being. Root activity tends to
raise the pH (potential Hydrogen) in the soil slowly turning the soil more acidic. A hayfield will
almost always show a low reading on a pH test which is quickly raised after plowing as broken
down organic material releases many basic material like calcium and phosphorus to the soil
again.
Soil pH:
Soil pH stands for potential Hydrogen. Liming the soil has created the confusion for some that
the pH is caused by the calcium content of the soil. What matters here is that liming has the
positive consequence of removing some of the hydrogen on the available “parking spaces” by
replacing them with calcium. Adding gypsum does not change the pH even though it contains a
© Jean-Paul Courtens 2010
Page 36
lot of calcium and this is because the sulfate component of gypsum carries a negative charge.
The need to raise the pH is determined by a soil test.
Mg
SO4-2
+22
+2
Ca
H
+
1
root
+1
Na
+1
H
+
1
H
Na
+22
Mg
Soil particle
+
1
+2
Ca
+22
Mg
HCO3
-
NO3-
SO4-2
HCO3
HCO3
H2O4P
-
Soil particle
-
NO3HCO3
-
-
H2O4P
Basic cation
Acidic anion
Drawing after Bemesting en Meststoffen Rinsema et al
The pH value in a soil test indicates whether lime is needed but the soil type will determine how
much lime is needed. The amount of lime to apply is dependent on the reserved soil acidity. This
is measured in the lab and indicated by a buffer index. The lower the number of the buffer index
© Jean-Paul Courtens 2010
Page 37
the more lime is needed. The buffer index is related to the clay and organic matter content and
the structure of the soil. Soils high in organic matter or clay will need more lime to raise the pH as
they have the ability to store more basic material (calcium, magnesium potassium etc) than a
sandy soil low in organic matter. This ability to absorb more basic material reflects in the
requirement for more lime to bring the pH up. In order to understand the buffer index we need to
go back to our picture of imagining the soil particles having “parking spots” for basic material.
Parking spots in this picture are negatively charged allowing a basic material (in this picture “a
car”) to be absorbed. Soils high in humus or clay have a lot of “parking spots” available which
can be occupied with hydrogen. Raising the pH is like kicking those hydrogen ions out of their
“parking spots”. You understand that a soil with a high CEC will need more calcium “cars” to kick
the hydrogen “cars” out of the “parking spots.
Each crop has a different optimum pH while this optimum differs for different soil types. Cropland
on a sandy soil performs best at a pH around 6 while this might fluctuate between 5.4 and 7.2 on
a clay soil. We aim on our cropland for a pH between 6.3 and 6.8.
Adjusting the pH is important for the following reasons:
1. Root development; a low pH has an impact on the ability of the roots to properly develop
2. Microbial activity is enhanced at more neutral pH levels.
3. Nutrient solubility:
Nitrogen: an acidic soil does not promote microbial activity and therefore less organic matter is
converted into ammonia and nitrate through the process of mineralization and nitrification.
Phosphorus is strongly dependent on a correct soil pH. Phosphorus is best available at a nearly
neutral pH. The amount of Calcium can have an impact on the availability of Phosphorus as well
as Ca tends to release the P ion easier than say Iron or Aluminum that are released at low pH
ratings.
Potassium is not affected by the pH
Magnesium is greatly affected by soil pH as low pH can cause leaching of Magnesium esp. on
sandy soils
With the exception of molybdenum, micro nutrients are released at a lower pH which could
cause the crops to take up too much iron, aluminum, or manganese and create toxicity. A high
pH can cause problems as boron, iron, copper and manganese can be tied up.
Plant Minerals:
Plants have a certain ability to choose the minerals or acids they take up although this has
certain limitations. Generally a plant will absorb nutrients that are most beneficial but it does not
have the ability to exclude certain harmful nutrients. Opposite ions have a positive influence in
the uptake of nutrients, while ions with a similar charge limits plant absorption. Here we can
speak of ion competition or ion antagonism. An excess of potassium can cause magnesium
deficiency, while excessive calcium can cause potassium deficiency. We can help the plants by
balancing the available minerals.
+2
Ca
A distinction is made between macronutrients and micronutrients.
The first group consists of
nitrogen, potassium, phosphorus, magnesium calcium and sulfur as they are taken up in relatively
© Jean-Paul Courtens 2010
Page 38
large quantities. The second group includes (but is not limited to) zinc, iron, molybdenum, silica,
boron, copper, chlorine, cobalt and selenium
Nitrogen (N):
Nitrogen is real dilemma for most organic farmers as deficiencies are the first and foremost
reason for achieving lower yields than our conventional neighbor, while we recognize that
liberal applications can create more problems than benefits. Generally speaking excess
nitrogen in plants expresses itself in an outbreak of sucking insects like aphids while
deficiencies show up in the form of eating damage by beetles. Creating the perfect
conditions for plant growth can only be accomplished in high organic matter soils as microbes
slowly release the nitrogen through mineralization. For each percent of organic matter we
can expect to free up about 20lb of nitrogen per acre through the process of mineralization.
Over time this will become unsustainable unless we renew the organic matter. For every 20
lb of nitrogen we will need to replenish about 1600 to 2000 lb of stable organic matter. Clearly
this is a very high energy input conversion, so deriving nitrogen from cover crops while
practicing reduced tillage is much more efficient.
Nitrogen is brought into the farm by the symbiotic activity of nitrogen fixing bacteria and
legumes. The trick is to keep it in the soil until our cash crops need it. Nitrogen is by nature
a gas and therefore elusive. It simply does not like to exist in a mineral form, and it always
needs a host to remain part of the solid part of the world. Large amounts of nitrogen can be
fixed while little or nothing is left in the soil for our cash crops with poor management
practices. Nitrogen gained is easily lost due to leaching, volatilization or erosion.
Nitrogen from cover crops, when plowed under, is released over a very short amount of time
and care should be taken to avoid losses. Deep moldboard plowing wastes most of the
nitrogen from a cover-crop as there is little active biological activity below 9 Inches. Most of
the nitrogen from cover crops consists of ammonia (highly volatile) which becomes toxic
when buried too deep. The nitrogen in manure consists of about half ammonia and the other
half in nitrate. In good compost, all ammonia is converted to nitrate. Generally, volatilization
and leaching of nitrogen is greatly reduced by good soil structure, proper incorporation, and
by crops grown after incorporation that absorb the available nitrogen.
Phosphorus (P):
Phosphorus is an elemental component in the formation of protein. It is an essential element
in the process of reproduction (RNA, DNA), and essential for plant growth. It stimulates
growth of young plants, giving them a good and vigorous start and greatly influences the
quality of the seed. It has an influence on a variety of physiological processes of the plant
like assimilation and respiration.
Phosphorus has a positive influence on root development of all crops which explains some of
the stunting that happens at deficient levels. It enhances maturity of all crops and increases
the sugar content, which is important in all of the fruit type vegetable like peppers, tomatoes,
squash sweet corn etc. It also enhances tillering of grains and improves quality of straw,
increases the number of potatoes per plant and the quality of the starch content. It also
improves the stand of a cover crop or hayfield, while poor stands, inundated with weeds, are
often an indication of low levels of P.
Phosphorus in organic materials is released on our farm solely by mineralization through the
activity of microorganism. Soil moisture and temperature greatly influence these processes.
Deficiency will be visible in the discoloration of the older leaves turn a reddish purple color. In
severe cases the plants will be completely stunted. We see phosphorus deficiency each
spring in our cole crops as the cold soil has little microbial activity. Most crops in this family
© Jean-Paul Courtens 2010
Page 39
(esp. cauliflower) are highly sensitive to P deficiency. As we have good reserves of P in our
soils the discoloration of the leaves disappears once the soil is warmed up.
Generally speaking vegetable crops have a low need for Phosphorus. The average take up
of phosphorus from vegetables out of the soil is only about 20 lb per season. Compost is a
source that is usually very high in phosphorus as the grains fed to animals contain high
amounts of it while very little is utilized by the animals. States like Maryland recognize the
problem of excessive phosphorus leaching out into the ground water from manure
applications. Laws have passed that also restrict the amount of compost spread per acre
each season.
Potassium (K):
Potassium plays an important role in tissue formation. Its role in the plant is indirect,
meaning that it does not make up any plant part. Instead, it acts as a catalyst regulating
enzymatic processes in the plant that are necessary for plant growth.
Potassium is important for a plant's ability to withstand extreme cold and hot temperatures,
drought and pests. Another responsibility in the plant is the regulation of water use.
Potassium affects water transport in the plant, maintains cell pressure and regulates the
opening and closing of stomata‟s (small openings found on the leaf responsible for cooling
and taking in carbon dioxide for photosynthesis).
Symptoms of potassium deficiency include yellowing of the lower leaves and, in severe
cases, leaf-tip dieback. Once symptoms are present, the plant's ability to withstand stress
conditions, such as high heat, drought and pests, is diminished.
Only small amounts the potassium in the soil is available to plants as the majority is tied up in
the mineral part of our soils. Through soil activity we are able to make this available to the
plants. For every lb of available potassium we can assume to have another 100 lb in reserve
tied up in soil particles.
Soil type and environmental conditions have an effect on the amount of potassium available
for plant use. Potassium availability is highest under warm, moist conditions in soils that are
well aerated with a neutral or slightly acidic pH. A wet cold spring provides poor conditions
for potassium uptake. Excessive calcium or magnesium levels will also affect the uptake of
potassium.
Silica (SiO2):
Silicon (Si) is the most abundant element in the soil. Silicon dioxide comprises up to 50
to 70 percent of the soil mass. All plants take up silicic acid as a consequence of silicon
dioxide becoming soluble as silicic acid.
Silica is not recognized as an essential element to plant growth but the beneficial effect on
this element on the growth, development, yield and disease resistance have been observed
in many different plant species. Silicic acid uptake is much greater by monocotyledons
(grains, grasses) than dicotyledons (clovers, most vegetables). It is reported that up to ten
percent of the dry matter of rice can be silica. Most research has been on rice where in some
cases applications of calcium silicate at 5 ton/ha replaced the need fungicides to control neck
and leaf blast (Chad Husby, the Role of Silicon in Plant Susceptibility to Disease,1998). In other studies it is
showed that silica acid promotes the formation of nodules in cowpeas (Nelwamondo, Dakora
Capetown University 1999). In sugar cane silica helps increase the sugar content (numerous studies
© Jean-Paul Courtens 2010
Page 40
1980), while in sorghum it helps the plant to develop greater
studies 1980) or anthracnose (Viçosa Federal University, 2009).
resistance to drought (numerous
Silica is also essential in the nutrition of animals in regulating bone calcification and its
structural role in connective tissues. Nevertheless most of the silica is excreted so the
manure contains high amount of silica. As silica has the ability to lower aluminum levels in
our brain, it has been reported to lower the incidence of Alzheimer‟s.
The application of soluble fertilizer has a large impact on the uptake of plants of silica
therefore indirectly causing a higher incidence of plant diseases. Silicon, the element, occurs
in nature as silicon dioxide (SiO2), often called silica, and an enormous variety of silicates.
Now, plants absorb their silicon from the soil after it is in a soluble form; it's then converted
into silica-containing fibers for their structural support. Plants differ in their ability to absorb Si
from the soil solution. Marschner, (Mineral Nutrition of Higher Plants. Academic Press, London 1995)
identifies three types of plants based on their capacity for Si absorption:
 Silicon accumulators include several primitive plants including the horsetails
(Equisetum) and wetland grasses such as paddy rice that contain Si at 5 percent to 10
percent of their leaf dry weight. This requires an active Si uptake by the roots.
 Si non-accumulators contain .5 percent to 1.5 percent Si in their dry leaf tissues and
include most grasses and cereal grain but also potatoes and turnips. At those levels
silica with its abrasive nature can wear out a few pair of jeans in a season by a person
that handles a lot of hay or straw, while potatoes are an excellent source for silica.
 The Si excluders contain less than .23 percent Si in their dry leaf tissues. But even at
.25 percent to .1 percent of dry tissues, Si is present at levels comparable to sulfur,
phosphorus and magnesium.
Calcium (Ca):
Calcium is very different from Silica. It behaves very differently in the soil. Sometimes it is
helpful to create a picture we can relate to in order to grasp the nature of the object we are
describing. Some people have described silica to a monk in a spotless white robe; a
substance that is part of this world but tends to be uninvolved while it communicates with the
gods. If we want to create a mental picture of calcium Popeye after eating some spinach
comes to my mind; it behaves reactionary, its intent is to better the world through action. This
quality becomes evident when we deal with burnt lime. Burnt lime is made by roasting
crushed limestone in a kiln to drive off carbon dioxide (CO2). This changes the chemical form
of the limestone from a carbonate to an oxide, leaving a material that is highly concentrated
in calcium oxide or calcium and magnesium oxide. Burnt lime is very unpleasant to handle as
it will burn they eyes, skin or lungs when we are exposed to the dust. Burnt lime has a strong
reactivity with moisture in the air. When people apply burnt lime (as it raises the pH very
rapidly) great care has to be taken as it tends to clump up on wet soil, and burn the plants.
Calcium as a being in this world has tied up most of the carbon dioxide. 75% of this gas is
tied up by sea shells and lime deposits. In this form calcium has lost its nature of being
Popeye as it is tied down by the carbon. Calcium carbonate is not very soluble and as
farmers we are aware of this as it will take up to a full season before the lime we spread will
affect the pH. Once in solution though it acts like Popeye again throwing all the hydrogen
ions of their “parking spots”.
Calcium when available in large amounts can tie up nutrients. Calcium rich soils have
problems with nutrient availability so it goes as with everything else, “too much of a good
thing” can be a problem.
© Jean-Paul Courtens 2010
Page 41
Sources of minerals from the OMRI list are:
Nitrogen: N fixation by legumes, compost, animal by-products (blood meal and fish fertilizer),
plant by-products (cotton meal, alfalfa meal, soybean meal, apple, and fermentation wastes),
mined sodium nitrate (Na NO3) (16-0-0) (should not exceed 20% of the total nitrogen need of the
crop).
Phosphorus: Compost (esp chicken), rock phosphate, animal by-products (bone meal; fish,
shrimp, & oyster scraps; leather)
Potassium: Compost, plant by-products (ash, dried seaweed), greensand, SulPoMag
(K2SO4•2MgSO4) (0-0-20-14), sulfate of potash (K2S O4) (0-0-50),
Magnesium: Dolomitic lime, Epsom salts (MgSO4), sulfate of potash magnesium, bone meal,
plant by-products (cottonseed meal, wood ash)
Calcium: chicken compost from layers, high calcium lime, gypsum (CaSO4), bone meal, ash
Sulfur: compost, plant by-products (cotton motes, peanut meal), elemental sulfur, gypsum
(CaSO4), Epsom salt (MgSO4), sulfate of potash (K2SO4) (0-0-50)
Boron: Solubor (17½% boron) (each quart weighs about 1½ lb and adds about ¼ lb of boron to
the acre. Borax (11 % boron) (Na2B4O7·10H2O)
Zn (Zinc): Zinc Cypress (10% zinc soluble)
DIFFERENT COMPOSITIONS OF SEVERAL ORGANIC FERTILIZERS
All quantities in lbs./ton, except the first column
type
manure
of
lbs./
180days
dry
matter
org.
matter
13,000
9,000
22,000
430
52
190
280
20
120
11
8
9
7.6
0.4
4
8
16
10
8
0.2
4
solid
urine
slurry
chicken
770
990
1760
460
40
160
320
10
126
15
13
14
18
1.8
9
7
9
8
1.8
1.2
1.5
solid
slurry
with bedding,
44
88
640
220
1,160
460
160
700
25
16
32
37
13
40
18
10
22
47
22
57
11
6
dairy-cow
solid
urine
slurry
pig
horse
N
P
620
500
10
6
Note: It is fair to say that vegetables -in their particular requirements of high
potassium and nitrogen but lower needs for phosphorus- do best with compost
made with out of hay-fed cow or horse manure. Above numbers are from lactating
cows fed generous amounts of grain (which creates a relative high P number)
K
Ca
Adapted from: Bemesting en Meststoffen by ir. W.T. Rinsema
© Jean-Paul Courtens 2010
Page 42
Roxbury Farm, Meyer Field I
© Jean-Paul Courtens 2010
(photo © by Brian Kimmel 2008)
Page 43