Effects of bush encroachment control in a communal managed area in the Taung region, North West Province, South Africa

Abstract

The communally managed Taung rangelands are degraded because of bush encroachment. Bush encroachment is defined as a natural continuous retrogressive ecological succession, resulting in the increase of both alien and indigenous encroacher woody species and a reduction in grass species composition. This in turn result to changes in soil chemical and physical properties. The knowledge of the interaction between bush encroachment, land-use and soil conditions is essential to sustainably manage these areas. More than 80 % of the respondents in the Taung area owns cattle. To mitigate poverty stress; many pastoralists in the Taung area resorted to high stocking rates, leading to high grazing pressures locally and thereby, led to bush encroachment. The Working for Water (WfW) programme identified the need to implement both mechanical and chemical bush control strategies within the Taung area. Eight study sites were selected for this study. Each of the selected sites had a control and an uncontrolled (benchmark) site. The prominent woody encroacher species within these rangelands were Senegalia mellifera, Vachellia tortilis, V. karroo and Tarchonanthus camphoratus. This posed a threat towards the water resources in Taung communal communities and their economic status.Soil samples were collected and analysed for soil chemical properties such as soil pH, carbon (C) and nitrogen (N) concentrations, C: N ratio, soil magnesium (Mg) and exchangeable magnesium content (Mg2+), soil phosphorus (P) and sodium (Na) concentrations, soil calcium (Ca) content, soil exchangeable (Ca2+) concentration, soil CEC and EC values and the percentage base saturation. The results revealed that, soil pH and carbon concentrations were slightly higher in the uncontrolled sites as compared to the controlled sites. Soil Ca2+, Mg2+ and K concentrations and CEC values were higher in controlled sites as compared to the uncontrolled sites. P concentration, N availability and C: N ratios were limited in both the controlled and uncontrolled sites. EC values varied between the controlledand uncontrolled sites.