THE INFLUENCE OF NITROGEN LEVELS, SOIL TY PE AND WATER-STRESS ON THE GROWTH-RATE AND WATER-USE EFFICIENCY OF PANICUM-MAXIMUM CV GATTON

The influence of N fertilisation, soil type and water stress on the gr owth rate and water use efficiency of Panicum maxiMum was evaluated in a pot trial at the University of Pretoria. There were 5 levels of N a pplication on 3 different soil types and the treatments were replicate d under conditions of water stress. it was concluded that N fertilizat ion, at levels higher than 80 kg N.ha-1, does have a significant effec t on both growth rate and water-use efficiency, but that its influence was overshadowed by soil type and availability of groundwater. Water- use efficiency also decreases as the season progresses. From the resul ts of this trial it seems to be good policy, to irrigate only till the first cut or the first half of the summer.