The Use of two models to calculate soil loss in Mberengwa communal lands, Zimbabwe
Date
1993
Authors
Bryden, John Andrew
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Abstract
The potential of using the Universal Soil Loss Equation (USLE) and the Soil Loss Estimation Method for Southern Africa (SLEMSA) to calculate soil loss In the Mberengwa Communal Lands of Zimbabwe is investigated. Both models have been used to predict soil loss over large areas of subsistence agriculture in the developing world. Design of the USLE was based on data gathered on conditions common to temperated latitudes of the U.S. In spite of the word "universal", the model was intended not to use globally but to slow soil erosion by water in areas of American commercial agriculture. The SLEMSA model originated in Zimbabwe. While it stresses the importance of ground cover to protect soil from high energy convective rainfall. SLEMSA also was designed for conditions disimilar to that found in Mberengwa's communal lands. Both models require information about soil erodibility, rainfall erosivity, slope angle and length, cropping practices and conservation methods. Both the predicted quantity and the distribution of soil loss vary considerably between the two models. While no conclusions can be made about the relative accuracy of the two models, the wide variation in results indicates that much research is needed in order to accurately model soil erosion in areas of subsistence agriculture.