Author
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Teasdale, John |
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Submitted to: Weed Management for Developing Countries
Publication Type: Book / Chapter Publication Acceptance Date: 12/2/2002 Publication Date: 12/1/2003 Citation: Teasdale, J.R. 2003. Principles and practices for using cover crops in weed management systems. In: Labrada, R., editor. Weed Management for Developing Countries. Add. 1, FAO Paper 120. Rome, Italy:FAO. p. 169-178. Interpretive Summary: Weeds are an important deterrent of crop production in the developing world. They compete with crops for essential resources and reduce yields. Because of the absence of expensive control technologies, much time and hardship is endured by women and children who must control weeds by hand. Educational resources are often lacking for training local scientists and extension personnel in ecological approaches to weed management. At the invitation of FAO, this chapter was prepared for a book on weed management for developing countries. This chapter outlines how cover crops may be used for weed management. It describes both the scientific principles that underlie weed responses to cover crop living and dead mulches and practical applications of this knowledge to weed control. This is designed to be a resource to scientists, teachers, students, and extension personnel in developing countries. Technical Abstract: Cover crops are plant species that are introduced into crop rotations to provide beneficial services to the agro-ecosystem. Some of the most important environmental services provided by cover crops include soil protection from erosion, capture and prevention of soil nutrient losses, fixation of nitrogen by legumes, increase in soil carbon and associated improvements in soil physical and chemical characteristics, decrease in soil temperature, increase in biological diversity including beneficial organisms, and suppression of weeds and pests (Sustainable Agriculture Network 1998). This chapter will focus on weed suppression by cover crops but the need to manage cover crops to optimize the totality of impacts on the ecosystem will be emphasized at the conclusion. Cover crops can be grouped into two categories, 1) annuals that are grown during an off-season or period of the year that is not favorable for crop production and that are killed before planting a cash crop and 2) living mulches that grow at the same time as the cash crop for all or a portion of the growing season. Cover crops that are killed before planting a cash crop influence weed control primarily through the influence of their residue on weed germination and establishment. Examples of this kind of cover crop are Vicia villosa Roth, a winter annual legume, and Secale cereale L., a winter annual cereal, which are adapted to grow during the cold season in temperate climates and are killed before planting a cash crop when temperatures become warmer. Examples of cover crops that are adapted to hot summer fallow periods in tropical and sub-tropical climates include annual legumes such as Mucuna spp. and Crotelaria juncea L. or warm-season annual grasses such as Sorghum spp. |
