Soil properties changes after short-term livestock exclusion in “degraded” communally managed rangelands in the western Bophirima District, South Africa

Abstract

Livestock grazing and detrimental overgrazing are commonly associated with severe rangeland degradation particularly in communally managed pastoral systems in South Africa. Effects of grazing exclusion on vegetation are well documented, but there is a dearth of quantitative research conducted in communal managed range-lands to investigate the extent of associated soil properties changes. This study compared soil characteristics between grazed and 6 years adjacent exclosure plots at three communally managed sites namely Austrey, Southey/Eska and Tseoge in the western Bophirima District. A slow rate of change in soil properties between the grazed and exclosure plots was observed and differences were site-specific where detected. Phosphorus was significantly different at Tseoge (p = 0.001) and nitrate at Southey/Eska site (p<0.0001). Soil organic carbon was not affected by grazing exclusion at all sites, but the activity of ß-glucosidase activity was significantly different between exclosure and grazed plots. The activity of dehydrogenase was significantly different at Southey/ Eska site only (p = 0.002), whereas soil microbial biomass showed significant difference only at Tseoge site (p = 0.03). These results suggest that short-term livestock removal does not lead to a significant improvement of soil condition, as reflected by changes in soil properties. Caution is recommended when interpreting these results beyond the constraints imposed by the design of the study and the lack of information about livestock management practices and regimes at the sites.

Keywords:

• bophirima district
• chemical properties
• communal grazing management
• enzyme activity
• exclo-sure
• microbial biomass