Nutrients in soil and vegetation around two artificial waterpoints in Eastern Botswana.
A comparison of the vegetation and soil was made around 2 boreholes, differing in cattle density and exploitation period, in the dry savanna of E. Botswana. Increased grazing and trampling pressure around the boreholes has caused vegetation zonation with a species-poor zone in the inmmediate vicinity of the boreholes, followed by thickets with Acacia species and Dichrostachys cinerea, transitional to tree savanna. Creation of the artificial water points has caused an increase in soil nutrients near the boreholes due to concentrated deposition of dung and urine, the amount dependent on cattle density and borehole age. The increased soil fertility is reflected in the nutrient content of the herbs and trees near the boreholes. A nutrient balance demonstrated that overgrazing severely affected the P balance of the savanna ecosystem.