Improvement of Nitrogen Fertilization Practices for Efficient Use by Wheat Irrigated With Saline Water under Mulching Using 15N Technique

Abstract

A FIELD experiment was carried out to investigate the effects of saline irrigation water and soil mulching on the growth and yield of cultivated wheat crop. Wheat yield for nonmulched treatment irrigated by fresh water (3366 kg.ha-1) was higher than the mulched one irrigated with fresh water (3227 kg.ha-1) and also higher than both mulched and non-mulched treatments irrigated by saline water of 6 and 8 dS.m-1. Under non-mulched condition, the treatment of the irrigated by 6 dS.m-1 recorded a higher production of2411 kg.ha-1 than those irrigated by 8 dS.m-1 (2231 kg.ha-1). In thesame sequence mulched treatment of the irrigated by 6 dS.m-1 recorded a higher yield (2936 kg ha-1) than the mulched one irrigated by 8 dS.m-1(2573 kg.ha-1).The nitrogen uptake by grain of wheat irrigated by fresh water and non-mulching treatments was much better thanthat in mulching treatments, but, mulching treatment combined with saline water (6, and 8 dS.m-1) was much better than non-mulched one. Similar trend was noticed with N uptake by straw.Proportion and absolute values ofNitrogen derived from fertilizer(Ndff) as well as nitrogen use efficiency (NUE)gained by grains or straw were severely reduced by increasing water salinity level as compared to those irrigated with fresh water. Mulching has a positive effect on combating salinity stress. It seems that, in general, mulching made the plants more able to derive more nitrogen from fertilizer and improved NUE. Nitrogen derived from fertilizer by grains was significantly higher than those of straw. Similar trend was noticed for NUE.