地下水埋深和施氮量对冬小麦灌浆及水氮利用影响

探讨地下水埋深和施氮量对华北地区冬小麦灌浆特性和水氮利用效率影响,以百农4199为试验材料,设置地下水埋深(GW2:2 m,GW3:3 m,GW4:4 m)和施氮量(N300:纯氮量300 kg/hm²,N240:纯氮量240 kg/hm²)2个因素,评估地下水埋深和施氮量对冬小麦灌浆特性、产量形成及水氮利用效率等影响.结果表明:小麦千粒质量与快速增长期时间拐点、平均灌浆速率、灌浆持续时间显著正相关;路径分析表明,地下水埋深主要是通过影响小麦单株籽粒质量、穗数、穗粒数来影响产量的,地下水埋深对产量影响的直接标准化路径系数为0.334(P<0.05),施氮量主要是通过影响单株籽粒质量和穗数来间接影响产量;地下水埋深相同时,N240施氮水平氮肥偏生产力NPP和水分利用效率WUE均显著高于N300施氮水平.故建议地下水埋深大于2 m地区小麦高产和农业绿色可持续发展的施氮量为240 kg/hm².

Effects of groundwater depth and nitrogen application rate on grain filling and water and nitrogen use efficiency of winter wheat

In order to investigate the effects of groundwater depth and nitrogen application rate on grain filling characteristics and water and nitrogen use efficiency of winter wheat in North China, taking Bainong 4 199 as experimental material, groundwater depth(GW2: 2 m, GW3: 3 m, GW4: 4 m)and nitrogen application rate(N300: pure nitrogen: 300 kg/hm², N240: pure nitrogen: 240 kg/hm²)were set to evaluate the effects of groundwater depth and nitrogen application rate on winter wheat yield formation, grain filling characteristics and water and nitrogen use efficiency. The results show that the 1 000-kernel weight of winter wheat was significantly positively correlated with turning point t₂, the average grain filling rate G_mean and the grain filling duration P. Path analysis showed that groundwater depth mainly affected wheat yield by influencing grain weight per plant, spike number and kernels per spike, the direct standardized path coefficient of groundwater depth on yield was 0.334(P<0.05), and nitrogen application rate indirectly affected wheat yield by influencing grain weight per plant and spike number. At the same groundwater depth, NPP and WUE of N240 application rate were significantly higher than those of N300 application rate. Therefore, the nitrogen application rate of 240 kg/hm² is recommended for winter wheat high yield and green and sustainable agricultural development.