Soil Indicators of Rangeland Degradation in a Semi-arid Communal District in South Africa

Rangeland degradation is a major threat to sustainable livestock production in South Africa. The changes in aboveground vegetation have mainly been used to describe rangeland degradation, but little research has been carried-out to assess the extent of soil degradation, particularly in communally managed grazing lands. The objective of this study is to provide some baseline reference indicators of soil quality and changes at three communal managed grazing sites (Austrey, Southey and Tseoge) in the Bophirima District in the North-West Province. This on-going study forms part of the Desert. Margins Program (DMP) in South Africa. Soils from benchmark plots (grazed and adjacent ungrazed exclosure) were monitored for indicators such as pH, organic carbon and phosphorus, dehydrogenase, beta-glucosidase and acid phosphatase in 2005 and 2006. The soils are predominantly sandy (+/- 95%) with low fertility (organic carbon ranging between 0.06% to 0.10%, and phosphorus from 6.3 to 8.66 mg kg(-1) irrespective of grazing or exclusion). At all sites, there were few significant differences between grazed and ungrazed plots for soil chemical properties, or for enzymes activities, but the sites did differ. The results were presented to and discussed with community members during workshops to raise awareness on soil degradation. At this early stage, it. was difficult to detect significant trends of soil properties resulting from grazing management. Long-term monitoring and further indicators are required for a thorough assessment of-soil properties responses. Furthermore, as land (soil) degradation is not only about the land, but also about people, a multi/interdisciplinary approach should be followed in analyzing soil degradation issues in these areas.