不同水氮管理模式对玉米地土壤氮素和肥料氮素的影响

Effects of Different Water and Nitrogen Managements on Soil Nitrogen and Fertilizer Nitrogen in Maize Field

为了解决东北地区灌溉条件下水氮合理施用问题,以大田试验为基础,采用15 N同位素示踪技术,设置3个灌水定额水平(W1:40 mm,W2:60 mm,W3:80 mm)和3个施氮量水平(N1:180 kg/hm^2,N2:240 kg/hm^2,N3:300 kg/hm^2),分析比较了不同水氮管理模式对玉米地土壤氮素的吸收、土壤无机氮残留、土壤-作物氮平衡以及肥料氮去向的影响。结果表明:随着施氮量的增加,0~100 cm土层铵态氮、硝态氮的含量和累积量均呈现增加的趋势;提高灌水量可以提高60~100 cm土层铵态氮累积量、80~100 cm土层硝态氮累积量。对土壤-作物氮平衡的研究表明,增加施氮量可以提高土壤无机氮残留量和氮素盈余,而作物氮素吸收量随着施氮量的增加呈先增后减的趋势,氮素盈余量和表观损失量随灌水量的增加表现为先降低后增加。肥料氮累积量随着施氮量的增加呈先增后减的趋势,施氮量300 kg/hm^2时肥料氮累积量占比21.27%~31.23%,肥料氮残留量和损失量所占比例均有所提高。玉米植株氮素中有66.70%~75.05%来自于对土壤氮的累积,随着施氮量的增加,玉米植株土壤氮素累积量呈先增后减的趋势。综合不同水氮管理模式对玉米地土壤无机氮残留、土壤-作物氮平衡以及肥料氮去向的影响得出,灌水60 mm、施氮240 kg/hm^2的水氮组合可保证肥料氮的充分利用,减少无机氮的残留和损失。

In order to solve the problem of rational application of water and nitrogen under irrigation conditions in Northeast China,an experiment with three irrigation levels(W1:40 mm,W2:60 mm,W3:80 mm)and three nitrogen levels(N1:180 kg/hm^2,N2:240 kg/hm^2,N3:300 kg/hm^2)was carried out in the field conditions with 15 N isotope tracer technique.The results showed that the accumulations of ammonia nitrogen and nitrate nitrogen in the 0~100 cm soil layer was increased with the increase of nitrogen application,so did the contents in the different layers.The ammonia nitrogen accumulation in 60~100 cm layer and the nitrate nitrogen accumulation in 80~100 cm layer were increased due to the increase of irrigation amount.The soil inorganic nitrogen residue and nitrogen surplus were increased with the increase of nitrogen application,however,the crop nitrogen absorption was decreased first and then increased.The nitrogen surplus and apparent loss was decreased first and then increased with the increase of irrigation water amount.The accumulation of fertilizer nitrogen was increased first and then decreased with the increase of nitrogen application.The proportion of accumulated fertilizer nitrogen was 21.27%~31.23%,and the proportion of residual fertilizer nitrogen and nitrogen loss were increased when 300 kg/hm^2 nitrogen was applied.As the nitrogen in maize plants,of which 66.70%~75.05% came from the accumulation of soil nitrogen.The accumulation of soil nitrogen in maize plants was increased first and then decreased with the increase of nitrogen application.Combined with the effects of different water and nitrogen management on inorganic nitrogen residue in maize soil,soil-crop nitrogen balance and the fate fertilizer nitrogen,the water and nitrogen combination of 60 mm irrigation and 240 kg/hm^2 nitrogen application can ensure the full utilization of fertilizer nitrogen and reduce the residue and loss of inorganic nitrogen.