EFFECT OF SALINE DRAINAGE WATER AND NITROGEN-FERTILIZATION ON KERNEL YIELD, VEGETATIVE GROWTH, AND NITROGEN AND CHLOROPHYLL CONTENTS OF HASSAWI RICE

A field trial was conducted to test the effect of different rates of fertilizer nitrogen (0, 100, 150, and 200 kg N ha-1) on the growth and yield of Hassawi rice. Drainage water significantly reduced the growth and yield of Hassawi rice, presumably because of its salinity. Drainage water decreased mean straw yield from 666 to 460 g m-2, plant height from 0.88 to 0.73 m, tillers per plant from 8.2 to 5.3, chlorophyll content of leaves from 4.4 to 3.3 mg g-1, and nitrogen content of leaves from 37.2 to 24.9 mmol kg-1. Kernel yield was reduced from 546 to 201 g m-1, spikes from 336 to 251 m-2, number of kernels from 37.9 to 30.4 per spike, and 100-kernel weight from 4.2 to 2.5 g. Yield and yield component increases were noted for all fertilizer treatments; however, yield increases due to fertilizer nitrogen were reduced rapidly as water salinity levels increased. Generally, the application of 150-200 kg N ha-1 significantly improved crop performance and yield. However, with drainage water, even up to 200 kg N ha-1 will not produce kernel yields as high as those produced with normal irrigation water and 0 kg N.