A comparative study of soil erosion in the Umfolozi Game Reserve and adjacent Kwazulu area from 1937 to 1983.

Abstract

This thesis describes a comparative study of actual and potential soil erosion in the Wilderness area of the Umfolozi Game Reserve, and a biophysiographically comparable adjacent traditional KwaZulu landuse area. Estimates of temporal and spatial variations in eroded surfaces, sparsely vegetated surfaces susceptible to erosion, and active gullies were obtained from five sets of sequential aerial photographs taken between 1937 and 1983. Estimates of the potential influence of rainfall erosivity, soil erodibility, topography, and changes in vegetation communities and landuse practices on these variations, were extrapolated from these aerial photographs as well as from maps, field surveys, records and other studies. Interrelationships between these potential influences, and the extent to which they actually contributed to the temporal and spatial variations in the three 'erosion' surfaces, were assessed visually using a geographic information systems thematic overlay technique, and computationally using a forward stepwise multiple regression procedure.