Conradie, W.J. “Timing of Nitrogen Fertilisation and the Effect of Poultry Manure on the Performance of Grapevines on Sandy Soil. I. Soil Analysis, Grape Yield and Vegetative Growth”. South African Journal of Enology and Viticulture 22, no. 2 (May 4, 2017): 53–59. Accessed March 5, 2026. https://www.journals.ac.za/sajev/article/view/2192.