推迟拔节水对小麦氮素积累与分配和硝态氮运移的影响

摘要：2007—2008年度以高产冬小麦品种济麦22为材料，设置2个拔节水灌溉时期，为拔节期和拔节后10 d；3个目标相对含水量，灌水后0~140 cm土层土壤相对含水量分别达到65%、75%、80%，以W1、W2、W3表示拔节期灌水处理，DW1、DW2、DW3表示拔节后10 d灌水处理；开花期均灌水至0~140 cm土层土壤相对含水量为70%，研究推迟拔节水对小麦氮素积累与分配和硝态氮运移的影响。结果表明：（1）W2和DW2处理有利于提高0~60 cm土层土壤硝态氮含量，促进籽粒氮素积累；营养器官贮藏氮素向籽粒的转运量、籽粒产量和氮肥偏生产力分别高于W1和DW1，与W3和DW3处理无显著差异；开花后植株氮素积累量、籽粒蛋白质含量和水分利用效率分别高于W3和DW3，是拔节期和拔节后10 d灌水的最优处理。（2）W2和DW2处理比较，DW2成熟期100~140 cm土层硝态氮残留量低于W2，籽粒产量、籽粒蛋白质含量、氮素吸收效率、氮肥偏生产力和水分利用效率均显著高于W2，是本试验条件下的最佳灌水方案。2008—2009生长季试验各处理变化趋势同2007—2008年度。

Effects of delayed irrigation at jointing stage on nitrogen accumulation and its allocation, and NO3-N migration in wheat

Irrigation is one of the most important measures to regulate plant metabolism in winter wheat(Triticum aestivuml). However, unsuitable irrigation managements would cause the decline of nitrogen use efficiency and grain yield, and increase NO₃-N content in deep soil layers. The field experiment was carried out to investigate the effects of delayed irrigation at jointing stage on nitrogen accumulation and its allocation, and NO₃-N migration in wheat with the high-yielding cultivar, Jimai 22. Soil water content was controlled by a new strategy that supplemental irrigation based on measuring soil moisture. In 2007-2008 growing season, the first irrigation was given at jointing stage or 10 d after jointing stage, and the soil relative water content in 0-140 cm soil layer arrived to 65%, 75%, and 80% after irrigations, respectively. The treatments irrigated at jointing stage are represented as W1, W2, W3, and treatments irrigated 10 d after jointing stage are represented as DW1, DW2, DW3. The second irrigation was given at anthesis stage, and the soil relative water content of all irrigation treatments reached to 70% after irrigation.In the treatments irrigated at jointing stage, the nitrogen translocation amount from vegetative organs to grains, nitrogen allocation amount into kernel at maturity stage, grain yield, nitrogen uptake efficiency and partial productivity of nitrogen applied were significantly higher in treatment W2 than in treatment W1, and there was no significant difference between those of treatment W2 and treatment W3. Compared with treatment W3, however, treatment W2 increased the NO₃-N content in 0-60 cm soil layer, plant nitrogen accumulation amount post anthesis, grain protein content, and water use efficiency (WUE), significantly. In the treatments irrigated 10 d after jointing stage, the nitrogen translocation amount from vegetative organs to grains, grain yield, and partial productivity of nitrogen applied were higher in treatment DW2 than in treatment DW1, and there was no significant difference between those of treatment DW2 and treatment DW3. While the NO₃-N content in 0-60 cm soil layer, plant nitrogen accumulation amount post anthesis, nitrogen allocation amount into kernel at maturity, grain protein content, nitrogen uptake efficiency and WUE were higher in treatment DW2 than in treatment DW3. Compared with treatment W2, treatment DW2 decreased the NO₃-N content in 100-140 cm soil layer at maturity stage, and increased the grain yield, grain protein content, nitrogen uptake efficiency, partial productivity of nitrogen applied and WUE, significantly. As a result, treatment DW2 may be considered to be the best irrigation regime under the current experiment condition. The change tendency of different treatments in 2008-2009 growing season was similar to that in 2007-2008 growing season.