TIMING OF NITROGEN APPLICATION TO ENHANCE CORN (ZEA-MAYS, L) YIELDS IN A DESERT CLIMATE

Experiments were conducted in two consecutive years to investigate the response of two corn (Zea mays, L.) cultivars, Eperon and Challenger, to timing of N fertilizer in a desert climate. Fertilizer was applied three rimes (at planting, 6 weeks after sowing (6WAS) and at 9WAS) to give a seasonal total of 180 kg N ha(-1). The N treatments were N-ooo (control), N-LOH (60 kg N ha(-1) at planting, none at 6WAS and 120 kg N ha(-1) at 9WAS), N-LLL (60 kg N ha(-1) at sowing, 6WAS and at 9WAS) and N-LHO (60 kg N ha(-1) at planting, 120 kg N ha(-1) at 6WAS and no ne at 9WAS). Generally, N-LHO was associated with the highest grain an d dry matter yields. Planes in N treated plots had significantly large r number of leaves and ear leaf N contents than the control at mid-sil k. High ear leaf N was associated with high leaf area index and dry ma tter yield. Based on these results, it would appear that the applicati on of 60 kg N ha(-1) at planting, followed by 120 kg N ha(-1) at 6WAS (N-LHO) is the most suitable for enhancing corn yields in the desert c limate.