Effect of Deficit Irrigation on Water and Nitrogen Use of Spring Wheat

The objective of this study is to explore the best coupling form of water and nitrogen in arid areas of northwest China. Field experiment was conducted in the oasis region of Shiyang River Basin, and the interactive impact of water and nitrogen nutrition on use of water and nitrogen of spring wheat was investigated. The results showed that nitrogen rate and irrigation in jointing and heading stages impacted on spring wheat yield remarkably. With nitrogen rate (168 kg/hm2), irrigation (90 mm) in jointing stage, and irrigation (70 mm) in heading stage, grain yield was higher. Water use efficiency would be high, when the irrigation in tillering and filling stages both were 30 mm. Soil mineral nitrogen accumulation was mainly nitrate nitrogen, which was positively correlated with nitrogen rate in earlier stage. Nitrogen rate and irrigation in jointing and filling stage impacted on plant nitrogen accumulation remarkably, plant nitrogen accumulation came to maximum when nitrogen rate (168 kg/hm2), irrigation (90 mm) in jointing stage and irrigation (70 mm) in filling stage were applied. And nitrogen use efficiency came to maximum under nitrogen rate (56 kg/hm2), irrigation (90 mm) in jointing stage. Considering high grain yield and use of water and nitrogen, the primary suggestion on mode of irrigation and nitrogen rate of spring wheat in Shiyang River Basin were nitrogen rate (168 kg/hm2), irrigation (90 mm) in jointing stage and irrigation (70 mm) in tillering, heading and filling stages.