优化施氮对河套灌区氧化亚氮排放和氨挥发的影响

以河套灌区盐化潮土为研究对象,采用静态暗箱-气相色谱法和通气法研究了4个施肥处理(不施肥(CK)、传统施肥(CON)、优化处理1(OPT1,减氮53.3%)、优化处理2(OPT2,减氮53.3%+硝化抑制剂))对河套灌区玉米农田氧化亚氮(N_2O-N)排放、氨挥发(NH_3-N)损失和玉米产量的影响.结果表明:氮肥减量显著降低了土壤N_2O-N排放和NH_3-N挥发;相比于CON处理,OPT1处理的N_2O-N排放量和NH_3-N挥发量分别降低了45.2%和68.8%(p0.05),但N_2O-N损失氮素比率增加了9.7%(p0.05).施用硝化抑制剂可显著降低土壤N_2O-N排放,与OPT1处理相比,OPT2处理可降低34.6%(p0.05)的N_2O-N排放和41.5%(p0.05)的N_2O-N损失氮素比率,但NH_3-N挥发增加了47.5%(p0.05).OPT1处理显著降低了玉米产量,降幅达22.1%(p0.05),而OPT2处理相对于OPT1处理增产32.9%(p0.05),与传统施肥处理无差异.因此,综合N_2O-N排放、NH_3-N挥发及玉米产量可知,OPT2是较为合理的施肥措施,值得在河套灌区推广.

Effect of optimized nitrogen application on nitrous oxide emission and ammonia volatilization in Hetao irrigation area

A field study was conducted to investigate the effect of optimization of the nitrogen fertilizer management on nitrous oxide (N₂O-N) emission and ammonia volatilization (NH₃-N) from maize fields in the Hetao irrigation area. Seasonal variations of N₂O-N flux and NH₃-N volatization were monitored using static chamber-gas chromatography method and aeration method, respectively. Four treatments, i.e. non-fertilizer (CK), conventional fertilization (CON), optimized treatment 1 (OPT1, reducing the nitrogen fertilization rate by 53.3%), optimized treatment 2 (OPT2, OPT1 plus the use of nitrification inhibitor), were tested in the experiment. The results showed that reducing nitrogen fertilizer significantly reduced N₂O-N emission and NH₃-N volatization. Compared to treatment CON, treatment OPT1 reduced N₂O-N emission and NH₃-N volatization by 45.2% and 68.8% (p<0.05), respectively, while increasing the amount of applied N lost as N₂O-N by 9.7%(p<0.05). The use of nitrification inhibitor significantly reduced N₂O-N emission and the amount of applied N lost as N₂O-N by 34.6%(p<0.05) and 41.5% (p<0.05), respectively, in comparison with Treatment OPT1, but its NH₃-N volatization was 47.5%(p<0.05) higher than that of treatment OPT1. Compared to treatment CON, treatment OPT1 reduced maize yield by 22.1% (p<0.05), treatment OPT2 increased yield by 32.9%(p<0.05) compared to treatment OPT1 (p<0.05) and there is no difference in maize yield between treatment OPT2 and treatment CON. Therefore, based on comprehensive consideration of N₂O-N emission, NH₃ volatilization and maize yield, combination of reduction of nitrogen fertilization rate and the use of nitrification maybe is a reasonable field management practice in Hetao irrigation area.