Abstract: In order to establish an efficient irrigation model to save water and fertilizer for winter wheat (Triticum aestivum), a field experiment was conducted to study the effects of different water application amounts of low-pressure sprinkler irrigation on the spatiotemporal distribution of nitrogen in soilwinter wheat system and the wheat grain yield, with the traditional surface irrigation (flooding irrigation) as the control. Lowpressure sprinkler irrigation decreased the soil compaction significantly, increased the soil urease activity after flowering stage, and made the soil NO₃^--N and NH₄⁺-N concentrated in 0-60 cm root zone, preventing the further leakage of water and fertilizer nitrogen. As compared with flooding irrigation, low-pressure sprinkler irrigation decreased the peak of ammonia volatilization rate and the total amount of ammonia volatilization significantly, and increased the total nitrogen content and nitrogen transport rate of plant leaves, sheaths, and stems considerably. Both the wheat grain yield and the water and nitrogen use efficiency under low-pressure sprinkler irrigation were increased to different extent, and the treatment with 15% reduction of water application amount obtained the highest grain yield and the highest water and nitrogen use efficiency while the least losses of water and fertilizer nitrogen.

Key words: wheat, supplemental irrigation based on soil moisture, photosynthetic characteristics, enzyme activity of flag leaf, grain yield.