Improved rainfed farming for semiarid tropics-implications for soil and water conservationPPathakauthorS MMirandaauthorS AEl-SwaifyauthorAlfisols and Vertisols are major soil orders found in the semiarid tropics. In most semiarid regions, the average annual rainfall would seem to be enough to produce one or two crops per year; however, rainfall patterns are erratic with frequent dry periods within the rainy season. The uncertainties have kept farmers from investing substantially in the development of the land resource base and in the use of high yielding varieties, fertilizers, and other inputs (4). Increased population has resulted in a need for fundamental changes in production systems. Shifting cultivation is being replaced by permanent agriculture, and farmers' attempts to further increase production have caused an extension of agriculture to marginal lands subject to frequent crop failure, primarily because of inadequate moisture. Intensified land use under existing systems may become self-defeating because it results in increased runoff and soil erosion, reduced groundwater recharge and downstream flooding of agricultural lands. As a result, the land resource base is shrinking and its productive capacity is diminishing. Thus, a scheme of resource management combining effective conservation and utilization of soil and water with crop production systems that maintain productivity and assure dependable harvest is urgently required (5).Soil Science1985Soil Conservation Society of AmericaBook Section