Working Towards a P-Response Model for Pinus radiata in the Tsitsikamma

SYNOPSIS Long-term response of Pinus radiata to P-application at time of planting was recorded on representative soil types of the Tsitsikamma. P-response models were developed for future use on the shale-derived incised plateau. Significant responses on duplex soils derived from TMS have also been recorded, with P-treated P. radiata providing significantly better growth responses than those recorded in Pinus elliottii and Pinus pinaster. However, responses to P-treatment were highly significant for all three species. Recommendations for the use of phosphate fertilisation for the Tsitsikamma plateau are presented.