Ogbazghi, ZM, et al. “Modelling Maize Grain Yield and Nitrate Leaching from Sludge-Amended Soils across Agro-Ecological Zones: A Case Study from South Africa”. Water SA, vol. 45, no. 4 October, Oct. 2019, doi:10.17159/wsa/2019.v45.i4.7548.