不同测墒补灌水平对小麦水氮利用及土壤硝态氮淋溶的影响

于2012—2014年两个小麦生长季，以全生育期不灌水（W₀）为对照，设置3个测墒补灌处理，即拔节和开花期使0～140 cm土层土壤平均相对含水量分别为65%(W₁)、70%(W₂)和75%(W_3)，研究其对土壤水利用、小麦氮素积累转运和土壤硝态氮分布及籽粒产量的影响.结果表明： W₂处理土壤贮水消耗量及占总耗水量的比例和灌溉水占总耗水量的比例较高，且吸收利用100～140 cm土层土壤贮水量较高.开花期营养器官氮素积累量及开花后氮素积累量均为W₂、W₃＞W₁＞W₀，成熟期营养器官氮素积累量为W₃＞W₂＞W₁＞W₀，营养器官氮素向籽粒中的转移量和成熟期籽粒氮素积累量均为W₂＞W₃＞W₁＞W₀.成熟期0～60 cm土层硝态氮含量表现为W₀＞W₁＞W₂＞W_3，80～140 cm土层为W₃显著高于其他处理，140～200 cm土层各处理间无显著差异.W₂处理的籽粒产量、水分利用效率、氮素吸收效率及氮肥偏生产力均最高.在本试验条件下，综合考虑籽粒产量、水分利用效率、氮素吸收效率及土壤硝态氮的淋溶，W₂处理是高产节水生态安全的最佳灌溉处理.

Effects of supplemental irrigation by monitoring soil moisture on the water nitrogen utilization of wheat and soil NO3--N leaching.

Field experiments were conducted during 2012-2014 wheat growing seasons. With no irrigation in the whole stage (W₀) treatment as control, three supplemental irrigation treatments were designed based on average relative soil moisture contents at 0-140 cm layer, at jointing and anthesis stages (65% for treatment W₁; 70% for treatment W₂; 75% for treatment W₃; respectively), to examine effects of supplemental irrigation on nitrogen accumulation and translocation, grain yield, water use efficiency, and soil nitrate nitrogen leaching in wheat field. Soil water consumption amount, the percentage of soil water consumption and water irrigation to total water consumption in W₂ were higher, and soil water consumption of W₂ in 100-140 cm soil layer was also higher. The nitrogen accumulation before anthesis and after anthesis were presented as W₂, W₃＞W₁＞W₀, the nitrogen accumulation in vegetative organs at maturity as W₃＞W₂＞W₁＞W₀, and the nitrogen translocation from vegetative organs to grain and the nitrogen accumulation in grain at maturity as W₂＞W₃＞W₁＞W₀. At maturity, soil NO₃^--N content in 0-60 cm soil layer was presented as W₀＞W₁＞W₂＞W₃, that in 80-140 cm soil layer was significantly higher in W₃ than in the other treatments, and no significant difference was found in 140-200 cm soil layer among all treatments. W₂ treatment obtained the highest grain yield, water use efficiency, nitrogen uptake efficiency and partial productivity of applied nitrogen. As far as grain yield, water use efficiency, nitrogen uptake efficiency and soil NO₃^--N leaching were concerned, the W₂ regime was the optimal irrigation treatment in this experiment.