Evaluation of a number of grass species for restoring degraded semi-arid rangelands in Southern Africa

The biophysical environment is an important determinant of land degradation in both commercial and communal land tenure systems in South Africa. According to a recent study on the status of land degradation, approximately 25% of the total land cover in South Africa is degraded. Several technologies exist to restore the soil and vegetation degraded areas in natural pastures. To improve the production and biodiversity potential for agricultural and conservation uses in these rangelands, a common restoration technology includes the cultivation the eroded and compacted soil surfaces by rip-ploughing and the re-vegetation with high productive, palatable and perennial species. Five grasses, Chloris gayana, Digitaria eriantha, Anthephora pubescens, Cenchrus ciliaris and Panicum maximum, were used in over-sowing trials in an semi-arid region with two types of soils, to evaluate their effectiveness to restore the degraded natural pasture. Results show that D. eriantha, C. gayana and P. maximum should be used in an over-sowing treatment to restore high clay or silt soil types, whereas A. pubescens and C. ciliaris are more suitable for sandy soils. The diversity in areas which were only rip-ploughed also increased considerably with palatable, perennial species such as Themeda triandra, Setaria sphacelata and Eragrostis curvula.