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Cover Crops
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Cover Crop Research at the Sustainable Agricultural Systems Lab


Cover crops are plants grown during the off-season when cash crops are not being produced. Research at the Sustainable Agricultural Systems Lab has identified optimum cover crop management systems for cash crop production and has determined many ecological services provided by cover crops.These pages will focus on information developed in this lab.General background information on cover crops can be obtained from the website links listed at the bottom of this page.


Cover Crop Management


Cover crop management systems have been developed for several climates in the U.S.:


Winter annual cover crops for temperate summer vegetable crops..

The development of a sustainable system for no-tillage production of fresh-market tomatoes with legume cover crops has been a hallmark accomplishment.Over 49,000 copies of USDA Farmers Bulletin 2280 have been requested in the past decade.


Abdul-Baki, A.A., and J.R. Teasdale. 2007. Sustainable production of fresh-market tomatoes and other summer vegetables with organic mulches. USDA-ARS Farmers' Bull. No. 2280 (Revised Oct. 2007). Download PDF.


Summer tropical cover crops for subtropical winter vegetable cropsA biologically-based system for winter production of fresh-market tomatoes was developed in collaboration with U.of Florida Homestead. The system consists of a cropping rotation in which nematode-resistant cover crops [cowpea, velvetbean, or sunn hemp] are followed by a nematode and Fusarium/Verticillium resistant tomato cultivar. Tomatoes in these cover crop based systems have produced equivalent or higher yields and net returns in selected years than the conventional methyl bromide fumigation based system).Additional research is needed to define the viability of this system across a wider range of nematode, disease, and soil conditions.These results do highlight that methyl bromide is not necessary under all conditions and that a cover crop based-system can be an economically viable alternative for growers of high-value crops in the southeastern U.S. In addition, the alternative system reduced soil erosion, improved soil fertility, and has great potential for protecting the environmentally fragile agro-ecosystem of the Everglades.

Abdul-Baki, A., Bryan H. H., Zinati, G, Klassen, W., Codallo, M. and Heckert, N.2001. Biomass yield and flower production in sunn hemp: Effect of cutting the main stem. Journal of Vegetable Crop Production 7:83-104.


Abdul-Baki, A.A., Klassen, W.,Bryan, H.H., Codallo, M., Hima, B.L., Wang, Q.R., Li, Y.C., Lu, Y.C., Handoo, Z.A. 2005.A biologically-based system for winter production of fresh market tomatoes in south Florida Proc.Fla.State Hort. Soc. 118:153-159.


Roberts, D.P., Abdul-Baki, A.A. Zasada, I.A. Meyer, S.L.F. and Klassen, W.2005. Biologically-based technologies for suppression of soilborne pathogens of vegetables. In Pandalai, S.G. (Ed.) Recent Research Developments in Applied Microbiology and Biochemistry.


Summer tropical cover crops for desert orchards.

Date production in the U.S. is localized in the Coachella Valley in southeastern California. Tree growth, yield, and fruit quality had been declining in spite of standard management practices including high fertilizer and irrigation inputs. This decline was caused by a number of stresses which included high soil compaction, trees with shallow roots, high salinity due to poor drainage, low fertility, lack of organic matter in sandy soils, and improper management of irrigation water. The ARS Sustainable Agricultural Systems Lab in collaboration with NRCS developed a two-step solution consisting of, first, a one-time slip plowing between the tree rows to a depth of 5 feet to break the hard pan and allow the movement of water and nutrients deeper into the soil profile and, second, a management system using a native legume cover crop, Lana vetch, to cover the soil surface between October and May of each year.The cover crop suppressed weeds, improved soil fertility, recycled macro- and micro-nutrients, improved water percolation, shaded the soil surface, reduced evaporation, and lowered soil temperature that was a source of severe stress to root function in this excessively hot region. Within three years of implementing the cover cropping system, tree growth per year tripled, yields significantly increased by an average of 12 to 20%, and fruit quality also improved. At the same time, production cost was reduced by $100/acre due to savings on cultivation, fertilizer, and water. Approximately 45% of the date orchards in Coachella Valley are presently applying the cover cropping system.In addition, this technology has been extended to other crops resulting in an increase of cover cropping acreage from 500 to 25,000 acres in the Coachella Valley, including use in approximately 40% of the grape acreage.


Characteristics of Hairy Vetch-Tomato System


A highly successful system for no-tillage production of vegetable crops in a hairy vetch cover crop was developed at the Beltsville Agricultural Research Center during the previous decade.Tomatoes grown in a hairy vetch cover crop were shown to:


••   Produce higher leaf area duration, marketable yield, and net returns than those grown with a standard black polyethylene mulch,

••        Reduce inputs of fertilizers, herbicides, and fungicides for producing fresh-market tomatoes.

••        Reduce water runoff, as well as sediment, nutrient, and pesticide losses in runoff by 75 to 95%,

••        Activate a suite of genes that are interlinked with delayed senescence and enhanced disease resistance in vetch grown tomatoes.


For more details click here.


Weed Suppression by Cover Crops


For information on the following topics link to


Understanding the Complexities of Cover Crop Residue Influences on Weed Emergence. 

PDF document available here.


Principles and Practices for using Cover Crops in Weed Management Systems.

See: Teasdale, J.R. 2003. Principles and practices for using cover crops in weed management systems. Pages 169-178 in R. Labrada (ed.) Weed Management for Developing Countries. FAO Plant Production and Protection Paper 120, Add.1, Rome, Italy. This chapter can be accessed online here.


On-Going Research


?         Breeding improved cultivars of hairy vetch with early flowering and improved winterhardiness.  [Tom Devine]

?         Determining molecular mechanisms for crop responses to cover crops.[Autar Mattoo]

?         Understanding rhizosphere and soil microbial populations associated with cover cropping.  [Jeff Buyer]

?         Enhancing weed [John Teasdale] and pest [Don Weber] suppression with cover crops.

?         Determining the behavior of allelopathic compounds in soil.  [Cliff Rice]


Links to Useful Cover Crop Websites


Sustainable Agriculture Network. 1998. Managing Cover Crops Profitably, Second Edition. Handbook Series Book 3. 212 p. Download PDF


University of California Cover Crop Resource Page with links to extensive databases. 


Overview of Cover Crops and Green Manures by Preston Sullivan. Published 2003 ATTRA Publication #IP024