The erodibility of soils can be described as their sensitivity to the effects of wind and water on the soil structure. This property is expressed as an erodibility index, where low values indicate high susceptibility to erosion, and high values correspondingly indicate a low susceptibility to erosion.

The erodibility index is determined by combining the effects of slope and soil type, rainfall intensity and land use. These aspects are represented by terrain morphology (soil and slope), mean annual rainfall and broad land use patterns.

High erosion potential regions are centered around Sekhukhuneland in the Northern Province and Mpumalanga, the Tugela Basin, and the upper reaches of the Kei, Fish, Sunday, Caledon and Doring Rivers. Since soil formation is a geological process requiring centuries to complete, stable soils can be viewed as important natural resources.

Population pressure on soil resources High population densities in areas of highly erodible soils have resulted in devastating soil erosion occurring in many areas of South Africa, compromising the ability of this resource to sustain vegetation, animals and people in those areas. Large areas of average to high soil erosion susceptibility, coinciding with areas of high population densities, exist both in the metropolitan and in the rural areas of South Africa.