Threats to soil and water resources in South Africa.

South Africa has always been subject to an arid climate, receiving only slightly more than half of the world's average precipitation. This precarious situation is further exacerbated by very high potential evapotranspiration and an extremely rapid population growth. This paper aims to evaluate the threats to the soil and water resources of South Africa. These resources are vital in ensuring sustainable food production. Physically, wind and water erosion, structural decay, subsoil compaction and soil surface crusting are of great concern. Chemically, acidification, salinization, and pollution are the main concerns; with acidification mainly limited to the humid eastern parts and salinization to the arid western parts of South Africa. Biological degradation is mainly driven by organic matter decline, reducing the already low soil organic carbon content of South African soils. The extent of organism decline and the concomitant pathogen increase is not that well-known. Water resources in South Africa are very limited and of variable certainty. Water use efficiency, especially in agriculture and forestry, should receive urgent attention, since these are the main consumers of this valuable resource. Sedimentation, salinization, and pollution constitute the main impacts on water quality. Water pollution arises mainly from point sources such as municipal effluent, with smaller impacts from industry and feedlots. Given the varied nature of institutions and role-players involved in soil and water degradation, it is vital that one or more national institutions take responsibility to monitor and at least attempt to rectify and/or manage the degradation of South Africa's soil and water resources. In this regard substantial financial support from the private sector would also be imperative.