水氮运筹对滴灌冬小麦产量和水氮利用效率的影响

为探究水氮运筹对滴灌冬小麦产量和水氮利用效率的效应，于2019—2021年开展了连续2年小麦田间试验，设置2个施氮水平210（N₁）和240（N₂）kg·hm^-2，4个灌水处理W₁（不灌水）、W₂（每次30 mm）、W₃（每次45 mm）、W₄（每次60 mm），分析不同处理小麦产量及水氮利用率相关指标。结果表明，2019—2021年，施氮量和灌水量对冬小麦抽穗期、扬花期和灌浆期叶片净光合速率的影响为极显著（P<0.01）或显著（P<0.05），且三个生育时期均以N₂W₄ 处理最高，与N₁W₄和N₂W₃处理间没有显著差异；三个生育时期的土壤铵态氮和硝态氮含量均以N₂W₃、N₁W₄或N₂W₄处理最低。小麦越冬期、灌浆期和成熟期土壤铵态氮与产量和氮肥偏生产力（NPFP）均呈显著或极显著负相关；抽穗期、灌浆期和成熟期土壤硝态氮与产量和NPFP均呈显著或极显著负相关。2个年度，水氮运筹较对照显著提高了冬小麦的产量和水氮利用效率，产量增幅分别为38.9%~62.0%和40.9%~68.3%，水分利用效率（WUE）增幅分别为8.0%~15.7% 和10.1%~16.4%，NPFP增幅分别为38.9%~62.0%和40.9%~65.5%；冬小麦产量和WUE均以N₂W₄处理最高，N₂W₃处理次之，两者间没有显著性差异；但N₂W₃处理的水分利用效率均显著高于N₂W₄处理。综上，在本试验条件下，施氮量240 kg·hm^-2、每次灌水45 mm（N₂W₃）为该地区滴灌冬小麦最佳水氮运筹组合，可以实现保障产量和提高水氮利用效率的目标。

Effect of Water and Nitrogen Management on Yield, and Water and Nitrogen Use Efficiency of Winter Wheat under Drip Irrigation

In order to explore the effects of water and nitrogen management on winter wheat yield and water and nitrogen use efficiency under drip irrigation, a field experiment of two consecutive winter wheat growing seasons with drip irrigation system was carried out from 2019 to 2021, with two nitrogen application levels: N₁ (210 kg·hm^-2) and N₂ (240 kg·hm^-2), and four irrigation amounts: W₁(no irrigation), W₂, W₃, and W₄ (30 mm, 45 mm, and 60 mm irrigation each time, respectively). The related indices of wheat yield, and water and nitrogen use efficiency under different treatments were analyzed. The results showed that nitrogen application rate and irrigation amount significantly affected on the net photosynthetic rate of leaves in the key growth period of winter wheat, and their effect on the net photosynthetic rate of leaves at heading, flowering and grain-filling stages of winter wheat in two consecutive growing seasons were the highest under N₂W₄ treatment, followed by N₁W₄ or N₂W₃ treatments, yet there was no significant difference among the three treatments. The contents of soil ammonium nitrogen and nitrate nitrogen in the key growth stages of wheat in the two consecutive wheat seasons were the lowest under N₂W₃, N₁W₄ or N₂W₄ treatments. Moreover, soil ammonium nitrogen was significantly negatively correlated with yield and partial factor productivity of nitrogen fertilizer(NPFP) at overwintering, grain-filling and harvest stages. Meanwhile, soil nitrate nitrogen was significantly negatively correlated with yield and NPFP at heading, grain-filling and harvest stages. Water and nitrogen management significantly improved the yield, and water and nitrogen use efficiency of winter wheat, in the two consecutive winter wheat seasons, with the increase rate of 38.9%-62.0% and 40.9%-68.3% for wheat yield, respectively, and 8.0%-15.7% and 10.1%-16.4% for water use efficiency(WUE), respectively, and 38.9%-62.0% and 40.9%-65.5% for the NPFP, respectively. The yield and WUE of winter wheat in the two consecutive growing seasons were the highest under N₂W₄ treatment, followed N₂W₃ treatment, and there was no significant difference between the two treatments. However, the irrigation efficiency of N₂W₃ treatment was significantly higher than that of N₂W₄ treatment in the two consecutive wheat growing seasons. In summary, the nitrogen application rate of 240 kg·hm^-2 and the irrigation amount of 45 mm each time (N₂W₃) was the best water and nitrogen management mode for drip irrigation under this experiment conditions, which can achieve the optimal goal by ensuring yield with improved water and nitrogen use efficiency.