麦棉套作模式下施氮量对小麦产量及氮素吸收量的影响

Effects of Nitrogen Amount on Wheat Yield and Nitrogen Absorption Amount in Wheat-cotton Intercropping System

在麦棉套作模式下,设纯氮施用量45、90、135、180、225、270和315 kg/hm^2计7个处理,以不施用氮肥处理为对照,研究了不同施氮量对孕穗期小麦旗叶SPAD、植株干物质积累和氮素吸收、植株氮素含量和吸收量、籽料氮素含量和吸收量、小麦产量性状和产量的影响。结果表明：随着施氮量的增加,施氮处理的小麦旗叶叶绿素含量、植株干重、植株氮素含量和吸收量基本呈增加趋势,小麦籽粒氮素吸收量、单位面积穗数、穗粒数、千粒重和产量呈先增加后降低趋势,其中,施氮量225 kg/hm^2处理产量最高,施氮量180 kg/hm^2处理次之。施氮处理的上述指标值均跃CK,除植株干重外,施氮量180-315 kg/hm^2处理的其他指标值差异均不显著,且基本显著跃其他施氮处理。施氮处理的氮素农学效率和生产效率均约CK,且随施氮量的增加呈降低趋势,其中施氮量270和315 kg/hm^2处理的氮素农学效率显著约其他施氮处理,氮素生产效率显著约施氮量45-180 kg/hm^2处理。综合考虑产量和成本,认为麦棉套作种植模式下小麦季的适宜施氮量为180-225 kg/hm^2。

In wheat-cotton intercropping system 7 nitrogen fertilizer treatments（45,90,135,180,225,270 and 315 kg/hm^2） were designed to study the effects of nitrogen amount on SPAD of flag leaves, dry weight accumulation of wheat plants,nitrogen absorption amount at booting stage,and nitrogen absorption amount in grains, wheat yield and yield components at harvest stage using no nitrogen as control.The results showed that with the increasing of nitrogen application,SPAD of flag leaves,dry weight of wheat plants, nitrogen absorption amount of plants increased, nitrogen absorption amount of grains, spike number per area, grain number per spike, 1 000 grain weight and yield first increased and then decreased,the yield reached maximum with the 225 kg/hm^2 nitrogen amount,then 180 kg/hm2 followed.The index value of 7 nitrogen treatments were all higher than CK,with nitrogen amount of 180-315 kg/hm^2 which were all significantly higher than that of others except dry weight.Nitrogen agronomic efficiency and production efficiency of nitrogen fertilizer treatment were all lower than that of CK, which was decreased with the increasing of nitrogen amount.Nitrogen agronomic efficiency of 270 and 315 kg/hm2 nitrogen amount significantly lower than others,andni trogen production efficiency of which was also lower than that of 45-180 kg/hm2 nitrogen amount.Comprehensive consideration of production and cost,the suitable nitrogen fertilizer rate was 180-225 kg/hm2 in wheat season of wheat-cotton intercropping system.