From: london@sunSITE.unc.edu (Larry London)
Subject: News from ATTRA: Concept of Organic Vegetable Production
Organization: University of North Carolina, Chapel Hill
Date: Thu, 19 Nov 1992 04:31:04 GMT

APPROPRIATE TECHNOLOGY TRANSFER FOR RURAL AREAS, P.O. BOX 3657,
Fayetteville, AR  72702; 1-800-346-9140


           ATTRA Summary:  Organic Vegetable Production


     Organic methods for vegetable production are based on
applying a system of biologically sound farming practices to
supply fertility and manage pests.  In-depth knowledge of the
soil, water, fertility, insect, animal, and plant systems of a
farm is used to develop management strategies for producing
vegetables organically.

     An important goal of organic production systems is to supply
fertility and other inputs from on-farm sources as much as
possible.  Initial prevention of pest problems is another
important goal of organic production systems.  Management
strategies for organic production promote the wise use of on-farm
resources and the prevention of pest problems by maintaining
balanced fertility, insect, and plant systems.  Strategies that
support this kind of prevention-based, whole-system approach
include:

     - maintaining crop diversity
     - practicing ecological soil management
     - using integrated pest management

     Any materials used for soil fertility or pest management in
organic production systems come from natural or biological sources
and are applied only as needed.  Synthetically manufactured
fertilizers, pesticides, or growth regulators are avoided in
organic systems.  Certification standards are used to verify that
foods labeled "certified organic" are produced without the use of
synthetic chemical fertilizers or pesticides.

     To be certified, farmers must document that they use only
those products acceptable to their certifying program.  They also
must document that they have used no prohibited chemicals on their
land or crops during a period of one to three years prior to
harvest.  Restrictions on other production practices may have to
be met as well.

     Organic growers' associations have been formed in many states
to promote organic farming and to certify organically grown food. 
Legislation defining organic production and labeling is in effect
in at least 17 states, and national certification legislation has
been passed.  Further information about organic certification can
be obtained by contacting ATTRA.


Economics

     Organic production costs and returns may differ from those in
conventional operations.  Organic fertilizers and pest management
materials often cost more than conventional materials.  Also,
during a conversion to organic methods, high initial inputs of
cultural practices, labor, and purchased fertilizers and pest
management materials may be needed until organic systems are
better established.  Prices for organic produce, however, are also
often higher than for conventional produce.

     Published information on the economics of organic production
is not widely available.  Some research that has been done is
summarized in:  "An Analysis of Costs and Returns in Conventional
and Organic Vegetable Production," by the New Alchemy Institute. 
They reported that:

     - labor is the biggest cost of organic vegetable production
       -- averaging 45% of input costs

     - materials are the biggest share of inputs -- averaging 50%
       of costs

     - customers must value organic produce quality over
       conventional quality to pay higher prices

     Farmers are increasingly attracted to organic production for
its income potential.  The organic produce market is expanding,
and premium prices are often paid for organic produce.  Farmer
attraction to organic production is also part of a national trend
toward using farming practices that are more sustainable, and less
chemically intensive, in order to protect soil, water, and
wildlife resources.


Managing Fertility

     A primary goal of organic systems is to supply and recycle
nutrients for fertility within the boundaries of the farm. 
Nutrients that can't be supplied from on-farm sources are obtained
outside the farm, usually as purchased inputs.  Examples of
on-farm sources or systems used to supply fertility are:

     - animal manures
     - composts
     - green manures
     - crop rotations

     Nutrients in animal manures and leftover plant materials can
be recycled on-farm by composting.  The stable, nutrient-rich
compost product that results is used to fertilize crops and is an
important part of organic soil fertility management.

     Crop rotations with cover crops and green manures are also an
important part of organic fertility management.  Cover crops
prevent soil erosion and improve water infiltration and other soil
qualities.  They also serve as green manures if they are later
tilled into the soil.  Green manure crops increase soil tilth,
organic matter, and available nutrients -- especially nitrogen.

     Purchased fertilizers and soil amendments may be especially
needed to meet crop nutritional requirements during a conversion
to organic farming.  Organic sources of nitrogen, phosphorous, or
potassium that can be obtained off-farm include:

     - animal and plant by-products, such as feather, blood, or
       fish meals; or cottonseed, alfalfa, soybean, or seaweed
       meals

     - mined minerals and rock powders, such as limestone, rock
       phosphate, or sulfate of potash magnesia

     Further information can be obtained from ATTRA on composting
and nutrient contributions from green manures and cover crops, on
sources of soluble nitrogen fertilizers, and on how to apply
organic fertilizer materials.


Managing Pests

     Weeds:

     Weeds can be managed in organic vegetable production by a
variety of methods, including:

     - physical control -- using mechanical cultivation and
       tillage, soil solarization, mulches, and flame weeding

     - cultural control -- using rotations and cover crops

     - biological control -- using weeder geese

     - chemical control -- using herbicidal soap

     The most critical period for reducing competition from weeds
is during the first few weeks of crop emergence.  In general, weed
management is a season-long task, especially for crops with a long
growing season and sparse canopy.

     A primary physical control for weeds is mechanical
cultivation and tillage.  For garden-scale vegetable production,
weeds can be managed with market gardening tools to cut emerging
weeds off just beneath the soil surface.  These tools include:

     - hand-held hoes -- such as colinear, shuffle, or oscillating
       hoes

     - wheel hoes -- with a one- or two-wheeled frame, a push
       handle, and attachable implements

     For larger operations of up to five acres, motor-driven
equipment used for overall or between-row cultivation includes:

     - front- and rear-tine rototillers -- for single-swath
       cultivation between rows

     - walk-behind tractors with a variety of implements -- for
       tilling, cultivating, and mowing between rows

     In large-scale operations of five or more acres, mechanical
weed management is handled with PTO-driven or tactor-drawn
implements to till or cultivate over large areas or multiple rows. 
A means of doing mechanized cultivation between plants within rows
can be essential in large-scale organic vegetable operations. 
Specialized tractor-drawn equipment designed to do precision
cultivation between plants is available from several suppliers.

     Another important physical weed management practice in
organic vegetable production is the use of mulch.  Besides
suppressing weeds, mulches can modify soil temperatures in the
spring so earlier planting is possible.  When used in summer,
mulches such as straw help buffer soil temperature highs so hot
weather crop stress is reduced.  Moisture conservation is another
important benefit of using mulch.

     When organic materials used for mulch, such as straw or
leaves, are later incorporated into the soil, they help to improve
soil structure and make nutrients more available.  Other physical
weed control practices include "soil solarization," to kill weeds
by raising soil temperatures, and "flame weeding," to kill
seedling weeds by searing them.

     A major form of cultural weed management is the use of crop
rotations to disrupt weed life cycles.  Cover crops -- especially
those planted as "living mulches" -- also provide effective
cultural suppression of weed growth by shading weeds or competing
with them for moisture and nutrients.

     An effective biological control used for weeds in certain
crops is weeder geese.  Weeder geese graze well on succulent
grassy weeds in vegetable, fruit, and nursery crops, but avoid
most broadleaf weed or crop plants.

     An organically acceptable chemical control for weeds now
available is a "herbicidal soap" product developed by Safers,
Inc., called Sharp-Shooter (TM).  The product is not yet
registered for use in food crops but may have uses in fallow weed
control and land preparation.

     Combining different types of weed management practices can be
a good way to achieve more complete suppression of weeds in
organic production systems.  Further information on mechanical
weed control, mulching, flame weeding, weeder geese, and chemical
controls for weeds in organic vegetable production is available
from ATTRA.


     Insects and diseases:

     Organic treatments for managing insect and disease problems
are generally less potent than conventional insecticides and
fungicides.  Organic farmers must rely more on applying cultural
techniques to prevent pests from getting established initially or
building to problem levels.  Crop rotations, resistant crop
varieties, proper management of fertility and moisture, and good
sanitation are used as basic cultural practices for preventing
outbreaks of insect and disease pests.


     The role of IPM:

     Applying "Integrated Pest Management" (IPM) is an effective
way to reduce economic losses to insects and diseases in organic
operations.  IPM involves combining, or "integrating," a variety
of pest management measures to get improved control while keeping
costs and negative environmental impacts to a minimum.  IPM
techniques are used to identify early signs of developing pest
problems.  Control treatments are applied in IPM only if potential
damage seems likely to exceed limits acceptable to the farmer.

     The key steps for applying IPM are to:

     - identify pests, and know about pest life cycles

     - monitor for signs of pest activity and any developing
       problems

     - know the type and amount of economic damage that can be
       tolerated

     - treat problems that could cause damage exceeding tolerable
       limits with an effective IPM strategy


     Treatment methods:

     Organic methods for treating insect and disease problems
include cultural, physical, biological, and chemical techniques. 
Cultural techniques make the environment less favorable for the
pests and include:  modified planting or harvesting dates, crop
rotations, tillage, and trap crops.

     Physical techniques are effective mainly for insect pests and
include:  handpicking, traps, physical barriers, and abrading
dusts that damage insect exoskeletons.  Soil solarization may
provide control for insect and disease pest organisms, and also
for nematodes.

     Biological controls for insect problems include the release
of predators, parasites, or disease organisms that attack insect
pests.  Biological treatments for plant diseases are also being
studied.

     Any chemical treatments used to control insect and disease
problems in organic operations are generally chosen to cause a
minimum of harm to beneficial organisms or the environment. 
Acceptable treatments dissipate quickly and are as specific to the
target pest as possible.  Organically acceptable chemical
treatments for insects include:

     - insecticidal soaps

     - horticultural oils

     - microbial insecticides -- such as "Bacillus thuringiensis"

     - botanical extracts from plants -- such as pyrethrum,
       rotenone, ryania, sabadilla, and neem

     For treatment of diseases in organic production, acceptable
materials include copper- or sulfur-based fungicides.  Compost
extracts and herbal sprays are examples of materials used to
suppress fungal diseases by farmers using "biodynamic" organic
methods.

     ATTRA has further information available on the management and
treatment of pests, on composting, green manuring, and organic
fertilizers, and on other topics related to organic vegetable
production.


For More Information

     This publication summarizes material from the ATTRA
Information Package:  "Organic Vegetable Production," prepared by
ATTRA Technical Specialist Steve Diver.  To request the full
Package, or for help with a specific question, call ATTRA
toll-free at:  1-800-346-9140.


           ATTRA Summary:  Organic Vegetable Production

     Written by:  Holly Winger
     Editorial and Project Director:  Christine Rugen
     (PageMaker Version Design/Layout:  Jim Tracy)

     May 1991


                    A Word about ATTRA and NCAT

     ATTRA is a federally-funded service offering free technical
information on sustainable agricultural production and marketing. 
ATTRA provides tailored responses to individual questions from
farmers, agricultural researchers and extensionists, wildlife
professionals, and others, and also distributes Information
Packages, Summaries, and Resource Lists on a range of general
topics in sustainable agriculture.

     ATTRA is funded by the U.S. Fish and Wildlife Service, Dept.
of the Interior, and managed by the National Center for
Appropriate Technology (NCAT) -- a non-profit organization
incorporated in 1976 to help communities and individuals find
sustainable ways to improve their quality of life using skills and
resources at hand.  The ATTRA staff includes technical specialists
in horticulture, agronomy, livestock production, aquaculture, and
wildlife management, and information specialists in agricultural
information transfer.  Their combined training and experience
includes advanced degrees in agriculture and years in consulting,
research, Cooperative Extension, large-scale farming, organic
market gardening, agricultural writing, and orchard, nursery, and
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