氮肥对豆茬冬小麦氮素利用及产量的影响

Effect of Nitrogen Application Rate on Nitrogen Utilizationand Yield of Wheat after Soybean Stubble

为探明黄淮海地区大豆茬口(S)冬小麦的最佳施氮策略,以玉米茬口(M)为对照,研究了不同施氮水平(0、180、240、300 kg·hm^(-2))下大豆茬口对冬小麦干物质积累动态、氮素吸收利用特征及产量的影响。结果表明,与玉米茬口相比,大豆茬口可显著提高不施氮处理下的小麦干物质积累速率及积累量,尤其在生育后期(开花至成熟期);可以提高0和180 kg·hm^(-2)施氮水平下冬小麦植株氮素吸收量,成熟期小麦籽粒氮素积累量分别提高了32.1%和9.5%,但当施氮量达到300 kg·hm^(-2)后,豆茬小麦的生长及氮素积累均受到显著抑制,总体呈现“低氮促进,高氮抑制”的氮肥效应。两种茬口冬小麦产量均在240 kg·hm^(-2)施氮量达到最高;在0和180 kg·hm^(-2)施氮量下,大豆茬口较玉米茬口均显著增产(P<0.05,25.8%和13.1%),在240和300 kg·hm^(-2)施氮量下,减产幅度分别为5.13%和13.9%,后者差异显著。豆茬小麦的氮肥利用率、生理效率及产量效应均低于玉米茬口。综上,豆茬冬小麦的施氮量应适当低于玉米茬口,黄淮海地区推荐施氮量不宜超过240 kg·hm^(-2),采用豆-麦部分替代玉-麦模式种植,可实现该地区减氮增效目标。

In order to explore the best nitrogen application strategy for wheat after soybean stubble in Huang-Huai-Hai plain,a field experiment was carried out to study the effects of different N application rates(0,180,240 and 300 kg·hm^(-2))on dry matter accumulation,nitrogen uptake and utilization,yield of winter wheat after soybean stubble(S),with that after maize stubble(M)as control.The results showed that S treatment significantly improved the dry matter accumulation rate and amount of wheat under 0 kg·hm^(-2)N application,mainly in the late growth stage(flowering to maturity).S treatment also improved the nitrogen uptake of winter wheat at 0 and 180 kg·hm^(-2)N application levels,and the grain nitrogen accumulation was increased by 32.1%and 9.5%at maturity stage,respectively.However,when the nitrogen application rate reached 300 kg·hm^(-2),the growth and nitrogen accumulation of wheat under S treatment were significantly inhibited.The general effect of nitrogen fertilizer under S was promoted by low nitrogen but inhibited by high nitrogen.The highest yield of winter wheat achieved at 240 kg·hm^(-2).Under the nitrogen application rate of 0 and 180 kg·hm^(-2),the yield under S treatment was significantly higher than that under M treatment(25.8%and 13.1%,respectively).Under the nitrogen application rate of 240 and 300 kg·hm^(-2),the yield was decreased by 5.13%and 13.9%,respectively,with significant difference in the latter.The nitrogen use efficiency and physiological efficiency of wheat after soybean stubble were lower than that after maize stubble,and the effect of nitrogen application on yield of wheat after soybean stubble was weaker than that after corn stubble.In conclusion,the nitrogen application rate of winter wheat after soybean should be lower than that after maize and the recommended nitrogen application rate should not exceed 240 kg·hm^(-2)in Huang-Huai-Hai region.The goal of reducing nitrogen and increasing efficiency in this region can be achieved by using soybean-wheat partially instead of maize-wheat cropping system.