Multiple cropping

Abstract: Tropical environments - climates, soils and cropping systems nitrogen fixing organisms in the tropics nitrogen fixation process and its role in the tropics tropical crops and cropping systems - cereal crops and grasses, wetland rice, grain legumes, legumes as animal fodder, plantation crops, agroforestry optimizing contributions from nitrogen fixation - mixed farming systems, environmental constraints, past approaches, realizing potential benefits

Abstract: Cover crops and living mulches bring many benefits to crop production. Interest in winter annual cover crops such as winter rye and hairy vetch for ground cover and soil erosion control has been increasing in the last 30 yr in some areas. The integration of cover crops into a cropping system by relay cropping, overseeding, interseeding, and double cropping may serve to provide and conserve nitrogen for grain crops, reduce soil erosion, reduce weed pressure, and increase soil organic matter content (Hartwig and Hoffman 1975). Hairy vetch has increased availability of nitrogen to succeeding crops, increased soil organic matter, improved soil structure and water infiltration, decreased water runoff, reduced surface soil temperature and water evaporation, improved weed control, and increased soil productivity (Frye et al. 1988). More recent research with perennial living mulches, such as crownvetch (Hartwig 1983), flatpea, birdsfoot trefoil, and white clover (Ammon et al. 1995), has added a new dimen...

Abstract: Multiple cropping describes forms of cropping practices where total production from a unit area of land in a farming year is achieved through growing crops simultaneously, sole crops in sequence, or a combination of mixed and sole crops in sequence. Multiple cropping for food production is in widespread use by farmers in the warmer parts of the world at all levels of agricultural technology. However, the form of multiple cropping varies from area to area depending on the farmers' total resources. Under conditions of "low level equilibrium" farming, as exists in much of the developing world (e.g., Africa, Latin America, parts of India), farmers operate with difficulties arising from low capital, unfavorable price relations, unsophisticated markets, and rudimentary infrastructure. Multiple cropping involving the growing of rain-fed crops in mixtures matches well the total resources available to these farmers in maintaining low but often adequate and relatively steady production. In conditions of "high level equilibrium" farming, as exists in areas such as the U. S., Taiwan, and parts of India, on-farm agricultural technology is geared towards commercial production. Here multiple cropping mostly involves the growing of sole crops in sequence, but in some cases where farming is both capital and labor intensive due to a high population and an absolute land shortage, growing crops in mixtures has become economically more attractive. In the future much of the food needed by the world's rural and urban population in the areas presently under conditions of low level equilibrium farming will have to be produced by farming communities under conditions of change in agricultural technology. While efforts by governments to improve institutional and administrative structures and support facilities will