Analysis of factor productivity in agricultural systems in Zimbabwe and application of Geographic Information Systems in soil erosion prediction

Abstract

Analysis was done to evaluate the utilization and productivity of agricultural factor inputs, calculate and simulate soil erosion rates using Geographic Information Systems (GIS) techniques in Nyota Ward of Chiweshe Communal Land, Zimbabwe and Balley Hooley Farm, Glendale, Zimbabwe. Results from the two areas were used for comparing factor use efficiency and respective rates of land degradation through soil erosion in the two agricultural systems. Crop production figures, crop market prices, variable and fixed costs of production were obtained from Zimbabwe Government publications. These figures were used to calculate rates of return to labor and capital for each of the systems under study. Land use classes of the area delineated from aerial photographs were digitized into an Arc/Info GIS. This was used to determine the area under crops and grazing. Range forage production figures in kilograms per hectare for the area were obtained from Agricultural Technical and Extension Services inventories. These were manipulated using the Grazing Land Applications 2.0.1 software package to calculate a Data on soil particulate composition, rainfall energy and vegetation cover were collected from a survey of the area. Relief data was obtained from orthophotos of the area. This information was digitized into the Arc/Info GIS and used for the calibration of Revised Universal Soil Loss Equation (RUSLE) and Modified Universal Soil Loss Equation (MUSLE) which were both used to predict soil erosion and sediment yield rates. Results from this analysis show higher returns to labor and capital on the commercial fan-n than the communal area. Maize was the only crop that yielded positive returns to labor and capital in the communal area. Returns to land and labor were positive for all crops grown on Balley Hooley farm. Soil erosion figures for the communal area have a higher mean than the commercial farm. Livestock grazing levels in the communal farming were higher than ecologically sound grazing capacity. These results indicate that it is necessary to carefully plan on factor optimization in communal agriculture in Zimbabwe so that farmers will be able to get positive returns to their factor inputs. Policy changes are necessary to bring about an agricultural commodity pricing system that gives fair producer prices so that farmers will be able to produce crops in which they have a comparative advantage without the risk of failing to meet their family food requirements. Socio-economic strategies to reduce livestock holdings in the communal area should be mapped out and implemented. On the basis of the two phenomena analyzed, the communal sector was found to be less sustainable than the commercial farming sector.