[Compostteas] Re: Organic Farming and Compost Teas

William F. Brinton wbrinton at woodsend.org
Sat Oct 12 14:47:38 EDT 2002


Under the new USDA guidelines for compost practices, fully in effect by
Oct 21, 2002, compost teas are no longer allowed or recognized as organic
for foodstuffs production. Our Compost Task Forced tried to save compost
teas based on a special exclusion that  would hold that unadulterated
extracts from compost that previously fulfilled the NOP compost guidelines
would be acceptable. However,  intense debate ensued and the end effect
was USDA provisionally withdrew acceptance of all compost teas for
food-stuff production (teas could be used on field forage and non edible
crops) until further research is performed.  Now it is up to practitioners
and scientific workers to assemble evidence and data that shows the proper
and safe use of compost teas!

Submitted by William Brinton

PS Our new book (Brinton, Droffner and Traenkner) on compost for disease
control and compost teas will be out early next year!


USDA links:

current rule : http://www.ams.usda.gov/nop/noppolicies.htm
GO TO COMPOST TASK FORCE REPORT

>> Original Task Force recommendation approved by
National Organic Standards Board

Compost Task Force Recommendation
April 18, 2002

INTRODUCTION

Section 205.203(c) of the soil fertility and crop nutrient management
practice standard in the USDA standard sets forth the fundamental
requirement for processing and applying plant and animal materials.
The section states, ?The producer must manage plant and animal
materials to maintain or improve soil organic matter content in a
manner that does not contribute to contamination of crops, soil, or
water by plant nutrients, pathogenic organisms, heavy metals, or
residues of prohibited substances?.  Subsequently, Section
205.203(c) states that plant and animal materials include raw animal
manure (205.203(c)(1)), compost (205.203(c)(2)), and uncomposted plant
materials (205.203(c)(3)).  The USDA standard establishes that raw
animal manure and uncomposted plant materials are distinct materials
that, when combined and processed, yield compost.  The standard also
contains management restrictions for crops on which raw manure has
been applied and specifies the conditions that must be maintained to
process compost.  Other than the common requirement that all
production practices used in organic production must maintain or
improve the natural resources of the operation, including soil and
water quality, there are no processing or application restrictions or
conditions for using composted or uncomposted plant materials that are
not mixed with animal materials.

At its Washington, DC meeting in October 2001, the National Organic
Standards Board (NOSB) reviewed the provisions in the USDA standard
for processing and applying plant and animal materials.  While
supportive of the fundamental requirement established in Section
205.203(c), the NOSB expressed concern that the provisions in Section
205.203(c)(1)-(3) could excessively restrict the processing and
application of beneficial plant and animal materials.  The NOSB
identified specific weaknesses in this part of the practice standard,
including:

*The C:N ratio range for compost is too narrow. Quality compost can be
 made with C:N ratios from as low as 15:1 and up to 60:1.

*The requirement for turning compost in a windrow system five times is too
prescriptive.

*The terms in-vessel, static aerated, windrow, and raw
manure are not defined.

*Compost tea is not addressed

*Vermicompost products are not addressed

*Manures that have been heat treated to eliminate pathogenic organisms
 without composting are not addressed.

The NOSB concluded that the USDA standard should be clarified to
accommodate a broader range of plant and animal materials and related
processing practices than specified in Section 205.203(c)(1)-(3).  The
intent of the crop nutrient and soil fertility management practice
standard should be to identify fundamental management parameters and
to establish threshold requirements for complying with those
parameters.  Site-specific variation in feedstock materials,
management practices, and production requirements dictate that organic
producers exercise flexibility in managing plant and animal materials
on their operations. The NOSB established the Compost Task Force to
clarify the parameters and requirements in the USDA standard for
processing and applying plant and animal materials in organic crop
production.

The Task Force concurs with the NOSB that many certified organic
farmers use plant and animal materials that are not adequately defined
or described in Section 205.203(c)(1) - (3). Examples of materials
that are incompletely addressed in the USDA standard are compost and
its liquid extract compost tea, vermiculture products, and processed
manure products.  The Task Force is especially concerned that many
producers process compost by selecting and managing plant and animal
materials differently than the specifications established in Section
205.203(c)(2)(i)-(iii). This recommendation provides producers and
certifying agents with a more comprehensive description of the plant
and animal materials allowed in organic crop production and the
conditions under which they must be processed.  Since it is
impractical to describe every combination of plant and animal material
and establish how it must be processed, this recommendation should
serve as guidance for producers and certifying agents.  Full
compliance with the provisions of Section 205.203(c) must be
documented in the producer?s organic system plan.

The Task Force endorses the fundamental requirement in Section
205.203(c) that all plant and animal materials used in organic crop
production must be managed to ?maintain or improve soil organic
matter content in a manner that does not contribute to contamination
of crops, soil, or water by plant nutrients, pathogenic organisms,
heavy metals, or residues of prohibited substances?.  The Task
Force interprets the subsequent provision that ?Animal and plant
materials include? not to be restrictive but rather as allowing
examples of such materials other than those specifically provided for
in Section 205.203(c)(i)-(iii).  This recommendation includes
descriptions and conditions for four such allowed plant and animal
materials: compost, compost tea, vermicompost products, and processed
manures. The Task Force recommends that producers and certifying
agents use the parameters established in Section 205.203(c) and the
management practices outlined in this recommendation for specific
plant and animal materials to evaluate compliance on a site-specific
basis.  The Task Force is not recommending changes to the practice
standard provisions for processing or applying raw manure or
uncomposted plant materials.

1. Compost

Definition:

Compost: Organic matter of plant and/or animal origin managed to
promote aerobic decomposition and an increase in temperature to
enhance its physical and nutritive properties as a soil amendment
while minimizing pathogenic organisms.  Compost must achieve a minimum
temperature of at least 131ºF (55 C)and remain there for a minimum of
3 days.

Producing compost that improves soil organic matter while not
contributing to contamination of crops, soil, or water by plant
nutrients, pathogenic and parasitic organisms, heavy metals or
residues of prohibited substances requires careful management.  The
fundamental conditions for composting are: 1) Compost shall
incorporate only allowed feedstock materials, except for incidental
residues that will not lead to contamination; 2) Compost shall undergo
an increase in temperature for a period of time to a level that
minimizes pathogenic organisms; 3) Compost shall release H20 and CO2
with a resultant loss of volume and weight; 4) Compost shall undergo a
decrease in carbon to nitrogen ratio and an increase in nutrient
stability.

The primary feedstock materials for making compost are organic matter
of plant and animal origin.  The USDA standard defines organic matter
as ?the remains, residues, or waste products of any organism.?
Organic matter of plant and animal origin includes crop residues,
non-crop plant material such as leaves and food waste, and manure and
other residues from animal bodies including soil invertebrates.
Compost may be produced from a single material of plant or animal
origin or from the combination of multiple materials.  The producer
may add a natural nonagricultural material or a synthetic material
allowed in organic crop production to compost for a specific
management purpose such as improved porosity.  When sourcing feedstock
materials, the producer must consider their origin and comply with the
requirement to prevent contact between organically managed crops and
prohibited substances.

Composting requires that the producer combine and manage feedstock
materials to achieve a documented increase in temperature.  Composting
begins in the mesophilic range (50ºF - 105ºF) and moves into the
thermophilic range (in excess of 105ºF) as decomposing organic matter
of plant and animal origin releases energy as heat.  Compost must
achieve a recognized minimum temperature of at least 131ºF (55 C) and
remain there for a minimum interval of 3 days to minimize pathogens
and parasites.  Compost piles must be turned or be managed in some
other acceptable way to ensure that all of the feedstock heats to the
minimum temperature.  Composting materials must be passively or
actively aerated by the design of the pile or through turning.
Physical maturation of compost transforms the feedstock materials and
little or no trace of their original nature is distinguishable upon
completion.  Particles in finished compost have been reduced in size
and become consistent and soil like in their texture.  After achieving
a minimum temperature of 131ºF for a minimum of 3 days, compost should
cure in the mesophilic range for at least 45 days or until the
producer can document that it is suitable for soil application.
Compost maturity involves physical and chemical components and must
include an appraisal of potential antagonisms between the compost and
plant or soil health such as excessive nutrients or salts.

A producer must document in their organic system plan all management
provisions or practices related to the fundamental conditions for
making compost: use of allowed feedstock materials, temperature
elevation and maintenance, decreases in weight, volume, and carbon to
nitrogen ratio, and increase in nutrient stability.  The certifying
agent must concur that the provisions in the organic system plan for
making compost will fulfill the parameters for these conditions.
Procedures for documenting compliance include measuring temperature,
time, moisture content, chemical composition, biological activity, and
particle size. These measurements may include testing feedstock
materials and compost for one or more characteristics including
initial and final carbon to nitrogen ratios, stability (using
ammonia/nitrate ratio, O2 demand, CO2 rate or other standard tests),
or pathogenic organisms.

2.  Compost and Vermicompost teas

The use of a liquid compost extract, or ?compost tea?, raises
special issues.  The preparation and use of compost tea and compost
extract has been increasing in the U.S. during recent years.  Organic
producers especially are interested in compost teas and extracts
because the preparations reportedly provide some degree of control of
foliar and root pathogenic organisms.  Various methods and practices
have developed for production of the teas or extracts since the
practice originated some years ago in Europe.  However, recent
research at the USDA Agricultural Research Service?s labs in
Beltsville, MD and Corvallis, OR shows that certain approaches to
compost tea or extract preparation are conducive to growth of enteric
bacterial pathogenic organisms, such as enterotoxigenic E. coli and
Salmonella.  The practices and procedures that lead to pathogen growth
in the prepared teas and extracts involve the addition of supplemental
nutrients such as sugars, molasses or other readily available
(soluble) carbon sources during batch production.

The researchers did not observed growth of enteric pathogenic
organisms when compost tea or extract was prepared only with water and
high quality compost.  By high quality compost, they mean compost that
has met criteria for destroying pathogenic organisms, i.e., 131ºF for
3 days, or compost that has less than 3 MPN salmonella per 4 grams
compost (dry weight) and less than 1000 MPN fecal coliforms.  The
critical determinant regarding pathogen growth in compost teas and
extracts is the addition of the carbon sources like sugars, molasses,
or yeast or malt extracts during the ?brewing? phase.

Recommendation: Compost teas if used in contact with crops less than
120 days before harvest must be made from high quality compost
described above and not prepared with addition of supplemental
nutrients such as sugars, molasses or other readily available
(soluble) carbon sources.


3. Vermicompost materials

Definition:

Vermicomposts are organic matter of plant and/or animal origin,
consisting mainly of finely-divided earthworm castings, produced
non-thermophilically with bioxidation and stabilization of the organic
material, due to interactions between aerobic microorganisms and
earthworms, as the material passes through the earthworm gut.

Vermicomposting, while not contributing to contamination of the
environment by heavy metals, needs careful preparation and management
of the organic wastes. Feed stocks for vermicompost materials include
organic matter of plant or animal origin; either a single material or
mixture, preferably thoroughly macerated and mixed before
processing. Pathogenic organisms are eliminated in 7-60 days,
depending on the technology used. All vermicomposting systems depend
upon regular additions of thin layers of organic matter at 1-3 day
intervals to maintain aerobicity and avoid temperature increases above
35 degrees C (95 degrees F) which will kill the earthworms. Permitted
methods and required duration of vermicomposting include outdoor
windrows (6-12 months), angled wedge systems (2-4 months), indoor
container systems (2-4 months) and continuous flow reactors (30-60
days).

Earthworms fragment the organic wastes into finely-divided materials
with a low C:N ratio, high microbial activity, nitrogen mostly in the
nitrate form, and potassium and phosphorus in soluble forms. For most
organic wastes, no traces of the raw materials are seen. Odors
disappear within 48-72 hours of vermicomposting and the finished
product should have an odor similar to soil. Processing must be
maintained at 70-90% moisture content with temperatures maintained in
the range of 18-30 degrees C (65-86 degrees F) for good
productivity. This should be achieved by monitoring temperatures
regularly to regulate timing of additions of wastes and adding
moisture through fine sprays as required.

4.  Processed manure materials

Manures that have been treated to reduce pathogenic organisms are
considered to be ?processed manure? materials.  Processed manure
materials must be made from manure that has been heated to a
temperature in excess of 150°F for one hour or more, dried to a
moisture level of 12% or less.  Processed manure products should be
negative for salmonella and less than 1000 MPN fecal coliform per 4
grams (dry wt.) material.  Since processed manure materials will not
contribute to contamination of the soil by pathogenic organisms, they
may be managed with many of the same requirements as compost.  Like
compost, processed manure materials do not have to be incorporated
into the soil and therefore can be applied as a top-dress or
side-dress. Similarly, there is no waiting period between application
of processed manure materials and harvest of the crop. Unlike compost,
however, these materials are highly soluble and have reduced
biological activity. Therefore, they should not be used as a primary
source of nutrients.


CONCLUSION

The Compost Task Force concurs with the NOSB that Sections
205.203(c)(1) - (3) of the USDA standard do not sufficiently define
or describe a variety of beneficial soil amendments and fertilizers
that have long been used in organic crop production.  The Task Force
endorses the fundamental requirement in Section 205.203(c) that all
plant and animal materials used in organic crop production must be
managed to ?maintain or improve soil organic matter content in a
manner that does not contribute to contamination of crops, soil, or
water by plant nutrients, pathogenic organisms, heavy metals, or
residues of prohibited substances?.  The Task Force supports
amending the soil fertility and crop nutrient management practice
standard by incorporating a comprehensive understanding of allowed
materials and practices.  Site-specific variation in feedstock
materials, management practices, and production requirements dictate
that organic producers exercise flexibility in managing plant and
animal materials on their operations.  Pending amendment of the USDA
standard, the Task Force recommends that producers and certifying
agents adhere to the management practices contained in this report
when using compost, compost tea, vermicompost materials, and processed

+++++++++++++++++++++++++++
William F. Brinton, Jr.
Woods End Research
PO Box 297
20 Old Rome Road
Mt Vernon ME 04352
207.293.2457 207.293.2488 fx
+++++++++++++++++++++++++++++++


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