**Acknowledgements**

This work was funded by the Water Research Commission (Project No. K5 2266). We thank Dr. A. Manson and Charmaine Mchunu from the Soil Fertility and Analytical Services (Cedara) of the Department of Agriculture and Environmental Affairs (DAEA) for their help with laboratory analysis, as well as the Potshini community for granting us access to their communal rangeland.
