Soil and crop management strategies to mitigate agricultural drought impacts

Abstract

Drought, though not considered a disaster by many, is one of the natural calamities encountered by humans. Drought may begin at any time, last indefinitely, and attain many degrees of severity. Its beginning is subtle, its progress is insidious, and its effects can be devastating (World Meteorological Organization [WMO], 1975). Often, drought is associated with aridity, although in reality it is a climatic aberration that can occur in any part of the globe, including humid and per humid regions. It is a condition relative to some long-term average of balance between rainfall and evapotranspiration in a particular area (Wilhite and Glantz, 1985). Droughts are not quick-onset disasters, like floods or typhoons, but are usually the eventual result of a set of weather sequences that require extensive periods of time to develop (Linsley et aI., 1959). Thus, according to Wilhite (1982), drought is a "creeping phenomenon," the effects of which accumulate slowly over a considerable period of time. However, drought means different things to different people and no universally accepted definition has so far been developed (Sastri et aI., 1982). Droughts are classified in three main categories (Das, 1981): meteorological (rainfall substantially below climatological expectations); hydrological (surface and subsurface water [i.e., reservoirs, lakes, rivers, and groundwater] depleted); and agricultural (inadequate soil moisture to support the growth of plants and crops to maturity)