氮肥对麦-玉轮作体系产量和氮肥效率的影响

Effect of nitrogen fertilizer on yield and nitrogen use efficiency in winter wheat-summer maize rotation system

为了评价氮肥周年运筹对冬小麦-夏玉米连作体系产量和氮肥效率的影响,为合理利用氮肥提供科学依据。2015～2017年在山西运城通过田间小区试验研究不同施氮肥水平下两季作物氮肥配比对小麦-玉米轮作体系中产量、干物质积累及养分利用效率的影响。试验设置3个周年氮肥投入水平(300、450、600kg/hm^2),3种小麦玉米氮肥分配比例(4∶6、5∶5、6∶4),共9个处理。结果表明:冬小麦、夏玉米单季作物产量均以450 kg/hm^2水平最高,且施肥量过多均不利于单季作物粒重的增加。周年作物产量以中氮水平450kg/hm^2下氮肥按5∶5分配在麦、玉两季时产量最高;随着施肥量的增加作物生物量、植株总吸氮量不断增加,而氮素利用效率、氮素吸收效率、氮素收获指数、氮肥偏生产力反而降低。氮肥利用率以施氮450 kg/hm^2水平最高,且在中高氮水平下,氮肥一半或重施在小麦上,更有利于作物周年生物量的增加和作物氮素吸收与利用。综合考虑产量和氮肥利用效率,在本试验条件下,周年施氮以450 kg/hm^2而且小麦玉米分配比例为5∶5效果最佳。

In order to evaluate the effects of nitrogen fertilizer on yield and nitrogen use efficiency for realizing the rational use of fertilizer,the experiment was conducted to study the effects of nitrogen amount and ratios on yield,dry matter accumulation and nitrogen use efficiency in winter wheat-summer maize rotation system in Yuncheng,South Shanxi Province.Three total nitrogen amounts(300,450 and 600 kg/hm^2)and three nitrogen distribution ratios in winter wheat and summer maize(4∶6,5∶5 and 6∶4)were used in 2015 to 2017.Highest yield were gained at 450 kg/hm^2 for winter wheat and summer maize in their single growth seasons,and excess nitrogen decreased grain weight.The highest total yields in the year was gained at 450 kg/hm^2 with 5∶5 nitrogen distribution ratio between winter wheat and summer maize.Dry matters and total nitrogen absorption increased,and nitrogen use efficiency,nitrogen absorption efficiency,nitrogen harvest index and nitrogen partial factor productivity decreased with nitrogen increase.The highest nitrogen use efficiency was gained at 450 kg/hm^2 with 5∶5 or 6∶4 nitrogen distribution ratio between winter wheat and summer maize.It is suggested applying N 450 kg/hm^2 with 5∶5 nitrogen distribution ratio between winter wheat and summer maize would gain the highest yield and higher nitrogen use efficiency.