不同施氮量对冬小麦田氮去向和气态损失的影响

Ampact of Different Nitrogen Application on Nitrogen Movement and Gaseous Loss of Winter Wheat Fields

该文研究氮肥对冬小麦田肥料氮素去向和气态损失的影响。通过布置田间微区试验,采用15N微区示踪技术和密闭室间歇通气法、密闭式静态箱法田间原位监测冬小麦氮肥的去向和气态损失。随着施氮量的增加,冬小麦产量和地上部吸氮量增加,但当施氮量高于150 kg/hm2时,产量出现降低的趋势,地上部吸氮比例也以土壤氮为主转变为肥料氮为主。4个施氮处理N75、N150、N225和N300的0-100 cm的土壤氮残留分别为32.6,26.8,34.7,40.6 kg/hm2。冬小麦田间土壤氨挥发排放总量随着施氮量的增加而增加,排放量在6.03～13.26kg/hm2之间,占施N量的5.4%～11.4%。N2O排放造成的氮素损失比例为0.08%～0.28%,苗期是冬小麦季N2O排放的主要时期。化肥氮在冬小麦当季作物吸收、土壤残留及损失量分别为37.2%～50.2%,26.7%～40.6%,17.4%～22.2%,且随着施氮量的增加而升高。在本试验条件下,150 kg/hm2是适宜的氮肥用量,产量最高,土壤氮残留最低,气态损失占肥料氮总损失的比例高于75 kg/hm2处理,但差异不显著(p<0.05)。因此控制氮肥用量是提高氮肥利用率的一项关键措施。

The impact of different nitrogen application on nitrogen movement of winter wheat fields and gaseous loss.By the methods of field micro-plot experiment with four nitrogen treatment： N75,N150,N225 and N300,15N tracer technique and closed micro-area chamber intermittent ventilation,sealed and static chamber in situ field to monitor nitrogen movement and gaseous loss of winter wheat fields.The yield of winter wheat and aboveground N uptake were increased with the nitrogen,except when the amount of nitrogen is higher than 150 kg/hm2,yield become falling,the N uptake proportion of aboveground turn from the main soil nitrogen into nitrogen-based fertilizers.The soil nitrogen residues of N75,N150,N225,and N300 of 0-100 cm were 32.6,26.8,34.7,40.6 kg/hm2.The winter wheat field emissions of ammonia volatilization from soil increase with the amount of nitrogen,the emissions were from 6.03 kg/hm2 to 13.26 kg/hm2 and accounted for 5.4%～11.4% of the amount of nitrogen.The nitrogen losses caused on the emissions of N2O by the ratio of 0.08%～0.28%,centralized in the period of wheat seedlings.The winter wheat seasonal crops absorption,residues and losses of fertilizer nitrogen were respectively 37.2%～50.2%,26.7%～40.6%,17.4%～22.2%,and increased with the amount of nitrogen.In the present the appropriate amount of nitrogen is 150 kg/hm2,in the level,the yield and the nitrogen utilization of crop both were the highest,yet,the residual of soil nitrogen was the lowest,the gaseous losses of nitrogen fertilizer higher than 75 kg/hm2 treatment,but the difference was not significant（p0.05）.Hence,the control was a key measure to increase nitrogen fertilizer efficiency.