氮水运筹对苏北平原稻茬麦干物质积累、产量和氮肥利用的影响

为明确苏北平原稻茬麦的最优氮水运筹模式，以淮麦30为材料，在大田测土施肥条件下，设置0 kg·hm^-2（N₀）、180 kg·hm^-2（N₁）、270 kg·hm^-2（N₂）3个施氮量和生育期不灌水（W₀）、灌拔节水（W₁）、灌拔节水+孕穗水（W₂）3个灌水处理，研究小麦干物质积累与转运、产量形成和氮素吸收与利用对不同氮水运筹的响应。结果表明，小麦干物质积累量、转运量和转运效率，氮素积累量、转运量和转运效率，花后干物质贡献率及氮素贡献率均随施氮量和灌水次数的增加而增加，各处理均以N₂W₂效果最佳。氮肥和灌水次数的增加对小麦成穗数、穗粒数、千粒重和产量、氮素收获指数与氮素利用效率均有显著促进作用，以N₂W₂效果最佳。氮肥农学效率、氮肥表观利用率和氮肥偏生产力则随施氮量增加而降低，以N₁W₂效果最佳；在相同氮肥水平下，灌水处理的上述三个指标较不灌水处理高。对本试验条件下各测定指标，氮肥在氮水运筹中起主导作用，且氮肥和灌水有显著的互作效应。综上，在苏北平原稻茬麦区，施氮量180 kg·hm^-2结合浇灌拔节水和孕穗水（W₂）的氮水模式可在协调小麦干物质和氮素的积累、转运与分配、促进增产的同时，提高氮肥利用效率，从而实现节氮增产的目标。

Effect of Nitrogen and Water Management on Dry Matter Accumulation, Yield and Nitrogen Utilization of Wheat Following Rice in Northern Jiangsu Plain

In order to clarify the optimal nitrogen and water management mode for wheat following rice in Northern Jiangsu Plain, Huaimai 30 was used as material. Under the conditions of field soil testing and fertilization, three nitrogen application rates of 0 kg·hm^-2(N₀), 180 kg·hm^-2(N₁), and 270 kg·hm^-2(N₂) and three irrigation treatments of no irrigation(W₀), irrigation at jointing stage(W₁), and irrigation at jointing and booting stage(W₂) were set up to study the response of the accumulation and transport of dry matter, yield formation, and nitrogen uptake and utilization to different nitrogen and water management in wheat. The results showed that the accumulation, transport amount and transport efficiency of dry matter, and nitrogen, post anthesis dry matter contribution rate and nitrogen contribution rate of wheat were increased with the increase of nitrogen application rate and irrigation time. N₂W₂ was the best treatment. The increase of nitrogen fertilizer and irrigation significantly promoted the spike number, grain number per ear, 1 000 grain weight and yield, nitrogen harvest index and nitrogen use efficiency, and N₂W₂ was the best treatment. The agronomic efficiency, apparent efficiency and partial productivity of nitrogen fertilizer were decreased with the increase of nitrogen application rate, and N₁W₂ was the best treatment. However, under the same nitrogen fertilizer level, irrigation treatment can improve the efficiency of the agronomic efficiency, apparent efficiency and partial productivity of nitrogen fertilizer. In this experiment, nitrogen fertilizer played a leading role in nitrogen and water management, and there was a significant interaction effect between nitrogen fertilizer and irrigation. In conclusion, in the wheat following rice area of Northern Jiangsu Plain, the nitrogen application rate is about 180 kg·hm^-2(N₁), combined with the irrigation at jointing and booting stage(W₂), which can coordinate the accumulation, transport and distribution of dry matter and nitrogen in wheat, promote yield, and improve the efficiency of nitrogen use, to achieve the goal of nitrogen saving and yield increase.