Sustainable land use and soil quality: organic matter as an indicator

Abstract

In this review the most recent approach to sustainable land use and the role that soil quality plays therein are described briefly. The requirements to which indicators must conform for the meaningful evaluation of the quality of soil and sustainability of land use are also elucidated. Thereafter the processes of physical, chemical and biological soil degradation are given. A concise discussion follows on the extent of physical and chemical soil degradation in South Africa, of which there is reliable information. Biological soil degradation is treated in more detail. Attention is given firstly to the role of soil organic matter in biogeochemical cycles. Thereafter the influence of different land use systems in the central parts of South Africa on the organic matter content and consequently the nitrogen, phosphorus and sulphur reserves of soils is discussed by using examples. The conclusion is that organic matter is an important indicator of soil quality and thus also of sustainable land use.