Using GIS to enhance agricultural planning: The example of inter-seasonal rainfall variability in Zimbabwe

Inter-seasonal rainfall variability is evaluated as a potential source of much needed information for agroecological or agroclimatological classifications. For some food crop production areas, inter-seasonal rainfall variability appears to dominate decisions in the crop-production strategy. We constructed 31 years worth of seasonal rainfall surfaces for Zimbabwe using techniques as described by Hutchinson (1995) and his software ANUSPLIN. We evaluated these surfaces in an effort to describe the main rainfall period (October to March) for Zimbabwe in terms of rainfall variability. Our results were then put into the context of an agroecological study which produced a Natural Regions map for Zimbabwe. GIS technology enables the synthesis and integration of many more data than was possible in a pre-computer era and robust rainfall variability surfaces contribute towards improved agroecological and agroclimatological classifications for planning (natural resource management and agricultural) purposes. GIS technology also enables a shift in the design of such agroecological or agroclimatological studies: dynamic characterization can readily produce objective specific classifications, classifications which use the wealth of data readily accessible in a GIS to produce maps and databases reflecting specific boundary conditions.