Spring 1993 (v5n3)
	Role of animals in sustainable agriculture. Parker, Charles F. In: Edwards, C.A., R. Lal, P. Madden, R.H. Miller and G. House (eds.) Sustainable Agricultural Systems. Soil and water Conservation Society, Ankeny, Iowa. pp.238-245.1990. Sustainable agricultural systems involve animals for their unique ability to use noncompetitive, nonrenewable resources, and for their integration with other farm practices. They complement plant production systems, and provide biological and economic diversity. Management of such mixed or integrated systems is the greatest challenge. Forages are grown on over half the land area of the United States. The economic success of forage farming requires animal grazing. Nutrient cycling, soil-water conservation, and enterprise flexibility are also affected. Animal reproductive cycles are timed to seasonal availability of forage, and differences among species (nutrient requirements, behavior, and diet preferences) allow the efficient use of resources in both biological and economic terms. Controlled intensive grazing, made possible by technological advances in electrified fencing, has improved the economic and biological output of animal-forage farming. Sustainable cropping systems often emphasize the use of nitrogen-fixing legumes for their value in soil improvement and as cover crops. Increased production of these legumes, which improve animal performance, should enhance the role of animals in these resource-conserving systems. Animals can also use other crop residues, which are currently produced in the United States in excess of amounts needed to prevent serious soil erosion. Returning animal feces and urine to the soil can help cycle nutrients, and animal grazing can help control weeds in agroforestry or pasture systems. For example, sheep can effectively control leafy spurge, a serious pest in the north central United States and Canada which is toxic to cattle. More attention should be paid to developing farming systems that exploit the complementarity and synergism between plants and animals in resource-conserving systems. (JSA.106) Contributed by Jill Auburn [ Back | Search | Feedback ]