Cover Crops for Sustainable Agriculture
Research Highlights
Cover crop definition
Online books
Photos
Acknowledgements
Key sources
Contact
This site contains research on cover crops for sustainable agriculture
developed or published by the Exploration
of Cover Crops for Sustainable Agriculture, with support from IDRC's program
initiatives MINGA (Alternative Approaches
to Natural Resource Management in Latin America and the Caribbean), People,
Land and Water (PLAW), and Community-based
Natural Resource Management (CBNRM) in cooperation with various other
agencies. This site provides empirical evidence of the contribution of
cover crops to sustainable agriculture.
Research Highlights
-
Innovation in agriculture must be needs driven, not technology driven.
Sustained and widespread use of cover crops (and perhaps any other soil
improving practice using organic inputs) will only occur if the biomass
(seeds, leaves, vines) can also be used in food and forage systems. Research
should focus on this challenge.
-
Cover crops provide significant benefits
to soil including nutrients, nutrient cycling, weed control, soil protection
and soil improvement. These benefits vary mainly in light of management
practices and climate affecting the quantity and timing of biomass produced.
-
Weed invasion (e.g. Imperata cylindrica) caused by shorter fallow periods
has significantly increased farm labour costs, especially in West Africa.
Cover crops are an effective, low cost and environmentally sensitive means
of controlling these weeds.
-
Spontaneous adoption of cover
crops by large numbers of small-holders has occurred in several regions.
Farmers adopt cover crops when the opportunity
costs of land are low, returns to labour are declining due to weed
invasion, inexpensive seed is readily available, and relative prices of
inputs such as fertilizers are high.
-
Farmers have led the process of innovation
with cover crops,resulting in feasible and adoptable technologies. Scientists
can speed up this process by building on farmer knowledge and practice.
Cover crops and green manures
H. David Thurston writes: "Considerable confusion occurs relative to the
use of the terms cover crops and green manures, as they are used in different
ways by different authors. The terms are often used interchangeably. Traditionally
the term "green manures" has referred to plants which are turned under
or incorporated into the soil while green, or soon after flowering, in
order to enrich the soil. In recent years however, the term has been used
more loosely, and green manure may sometimes refer to plants or plant vegetation
which may be applied as a mulch to the soil, either slashed and fresh or
after the plant has dried out.
As long ago as 1927 Pieters, in his comprehensive treatment of green
manures, stated that "Green manuring is the practice of enriching the soil
by turning under undecomposed plant material (except crop residues) either
in place or brought from a distance." He further stated "A cover crop is
one planted for the purpose of covering and protecting the soil." The Soil
Science Society of America (1987) defined green manure as plant material
incorporated into the soil while green or at maturity, for soil improvement.
Cover crops are any crops grown to produce soil cover, regardless of
whether they are later incorporated. They are used to cover and protect
the soil surface, although they may be turned under as green manures. Further,
the term cover crop also refers to crops grown between orchard trees or
on fields between cropping seasons to protect the land from leaching and
erosion (Martin 1975). Diver and Sullivan (1992) wrote: 'Any field or forage
crop grown to provide soil cover is a 'cover crop.' Since a crop grown
as a cover crop may later be soil-incorporated as a green manure, the two
practices are often referred to interchangeably.'"
Source: H. David Thurston, http://ppathw3.cals.cornell.edu/mba_project/gmcc/home.html
Acknowledgements
The following organizations have provided financial and technical support
for the research reported on this site.
International Development Research Centre (IDRC)
International Institute of Tropical
Agriculture (IITA)
The Sasakawa Africa Association
(SAA)
International Maize and
Wheat Improvement Center (CIMMYT)
Centro Internacional
de Información Sobre Cultivos de Cobertura (CIDICCO)
Centro Agronómico Tropical
de Investigación y Enseñanza (CATIE) and the English
version
Association of Advisors for a Sustainable, Ecological and Humane Agriculture
(COSECHA)
Cornell
University
Rockefeller Foundation
Online books
The IDRC Focus Collection contains full-text,
online books. By providing these texts online, IDRC aims to ensure that
research findings are disseminated rapidly and efficiently, to achieve
maximum impact from ongoing development research.
Cover Crops in Hillside Agriculture: Farmer
Innovation with Mucuna
Cover Crops in West Africa: Contributing
to Sustainable Agriculture
Indigenous
Strategies for Intensification of Shifting Cultivation in Southeast Asia
Green
Manure - Cover Crop Systems for Smallholders in Tropical and Subtropical
Regions
Photo archives
Please have a look at photographs showing the
use of cover crops by farmers in various regions.
Key sources
To the World - the IDRC Library's
comprehensive list of Internet sites relating to international development.
Cornell
University
Cornell International
Institute for Food, Agriculture and Development (CIIFAD)
The International Institute
for Rural Reconstruction (IIRR)
The Center
for New Crops & Plant Products, at Purdue University
University of California
Sustainable Agriculture Research and Education Program (SAREP) Cover Crop
Resource Page
Cover-Crop
Handbook. This is a searchable database.
Institute for Agriculture and
Trade Policy Global Food Security Resources
Appropriate Technology
Transfer for Rural Areas, Fayetteville, Arkansas, USA
La'akea Permaculture Gardens, a twenty five acre permaculture demonstration
farm, was established in 1991 on the island of Hawaii. Permaculture
and Sustainable Agriculture Related Links
The Agromisa Foundation
is a Dutch NGO that aims to strengthen the socioeconomic position of the
underprivileged rural population in developing countries. The Foundation
actively promotes small-scale sustainable agriculture making optimal use
of local resources.
The World Sustainable
Agriculture Association
The
Sustainable Earth Electronic Library (SEEL) is a digital library devoted
to the collection of publications that educate people on ways to preserve
and restore our natural environment. Plants
and sustainable agriculture selections
Rodale Institute
International
Ag-Sieve Newsletter
International Institute of Tropical
Agriculture (IITA)
Center
for Cover Crops Information and Seed Exchange in Africa
Contact
Daniel Buckles
Program Officer
IDRC
PO Box 8500
Ottawa, ON
Canada, K1G 3H9
Tel: (613) 236-6163 ext. 2358
E-mail: dbuckles@idrc.ca
Copyright 1998 © International Development
Research Centre, Ottawa, Canada
pub@idrc.ca | October 31,
1998
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