Healthy soil and sustainable growing

["TradingPostPaul" <tradingpost@riseup.net>]

http://attra.ncat.org/attra-pub/covercrop.html

Principal Uses of Cover Crops and Green Manures

"Green manuring" involves the soil incorporation of any field or forage
crop while green or soon after flowering, for the purpose of soil
improvement. A cover crop is any crop grown to provide soil cover,
regardless of whether it is later incorporated. Cover crops are grown
primarily to prevent soil erosion by wind and water. Cover crops and green
manures can be annual, biennial, or perennial herbaceous plants grown in a
pure or mixed stand during all or part of the year. In addition to
providing ground cover and, in the case of a legume, fixing nitrogen, they
also help suppress weeds and reduce insect pests and diseases. When cover
crops are planted to reduce nutrient leaching following a main crop, they
are often termed "catch crops."

Organic Matter and Soil Structure

A major benefit obtained from green manures is the addition of organic
matter to the soil. During the breakdown of organic matter by
microorganisms, compounds are formed that are resistant to
decomposition—such as gums, waxes, and resins. These compounds—and the
mycelia, mucus, and slime produced by the microorganisms—help bind
together soil particles as granules, or aggregates. A well-aggregated soil
tills easily, is well aerated, and has a high water infiltration rate.
Increased levels of organic matter also influence soil humus. Humus—the
substance that results as the end product of the decay of plant and animal
materials in the soil—provides a wide range of benefits to crop
production.

Sod-forming grass or grass-legume mixtures are important in crop rotations
because they help replenish organic matter lost during annual cultivation.
However, several years of sod production are sometimes required before
measurable changes in humus levels occur. In comparison, annual green
manures have a negligible effect on humus levels, because tillage and
cultivation are conducted each year. They do replenish the supply of
active, rapidly decomposing organic matter. (1)
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Web Resources

USDA's Sustainable Agriculture Network (SAN)
This site offers the second edition of Managing Cover Crops Profitably
online and a database of other sustainable agriculture research and
education projects. Many of these projects have a cover crop component and
some are focused on cover crops.

Managing Cover Crops Profitably
The online version of the second edition mentioned in the paper publication
listed above. It summarizes more than 30 cover crops by region. Published
in 2001.

UC SAREP Cover Crop Resource Page
This is the database of all databases when it comes to cover crops. The
UC-SAREP Cover Crop Database includes more than 5,000 items gleaned from
more than 600 separate sources, including journal articles, conference
proceedings, standard textbooks, unpublished data, and personal
communications from researchers and farmers. The information in the
database concerns the management and effects of more than 32 species of
plants usable as cover crops. More than 400 different cover crop images are
also available for online viewing. One limitation—the database is
regionally geared to the Mediterranean climate of California. Ideally, each
region of the U.S. should enjoy such site-specific information.

The Farming Connection
This site has farmer features and links to other cover crop sites. It also
contains seed sources, general information, Steve Groff's No-till
Vegetables video listing, and the first edition of Managing Cover Crops
Profitably.

Ohio State online Ag Facts
This site has an Online version of Cover Crop Fundamentals by Alan
Sundermeier, publication number AGF-142-99. This publication covers the
benefits of cover crops, planting times, types of cover crops, managing
cover crop growth, and return on investment.

Michigan Cover Crops, Michigan State University and Kellogg Biological
Station

The Basics of Green Manuring
P. Warman. EAP Publication 51, Ecological Agriculture Projects

Cover Crops & Green Manure Crops for Vegetable Farms
Ohio Vegetable Production Guide 2003

Summer Cover Crops for Tomato Production in South Florida

Cover Cropping in Potato Production
EAP Publication 71, Ecological Agriculture Projects

Cedar Meadow Farm's New Generation Cropping Systems
Steve Groff's New Generation Cropping Systems Web page. Shows action shots
of no-till planting into mechanically killed cover crops and ordering
information for Steve Groff's No-till Vegetables video mentioned above.

USDA Web Site
1997. By Aref Abdul-Baki and John R. Teasdale. USDA Farmers' Bulletin No.
2279. 23 p. This Web site provides the USDA Farmer's Bulletin that features
the no-till vegetable cropping system developed by scientists at the
USDA-ARS Vegetable Laboratory in Beltsville, Maryland. This system relies
on hairy vetch established in the fall, followed by a mow-down treatment
the following spring to prepare a no-till bed to transplant tomatoes and
other vegetable crops.

Multiple Impacts Cover Crops
John Luna, Oregon State University
A comprehensive piece on cover crops and their benefits.

Cover Cropping in Row and Field Crop Systems
An online educational slide series that provides visual images and text
describing the benefits and uses of cover cropping in annual crops like
vegetables. 52 slides.

Cover Crop Biology: A Mini-Review
Robert L. Bugg
Sustainable Agriculture Research & Education Program, University of
California

Cover Crops and Living Mulches. Sustainable Practices for Vegetable
Production in the South
Dr. Mary Peet, NCSU

Planting Dates, Rates, and Methods of Field and Forage Crops
University of Florida, Institute of Food and Agricultural Sciences
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paul, tradingpost@riseup.net