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通过3年田间试验,研究了减量施氮(N)对雨养区春玉米产量、温室气体排放、土壤硝态氮(NO_3~--N)残留的影响。试验于2013年4月至2015年9月在中国科学院长武黄土高原农业生态试验站进行,供试作物为春玉米,半覆膜种植,设常规施氮(N200)和减量施氮(N150)2个处理,定期测定土壤矿质N和氧化亚氮(N_2O)气体含量。结果表明:虽然N150处理较N200处理施N量减少了25%,但玉米产量无显著变化(P>0.05),三年平均为13.4(N200)、13.3(N150)t·hm~(-2);N150处理N2O累积排放量较N200处理降低24.3%;N200处理0~200 cm土壤剖面NO_3~--N残留量平均为210.2 kg·hm~(-2),N150处理则低至115.1 kg·hm~(-2);N200和N150处理的生育期耗水量差异不显著(P>0.05)。在渭北雨养农业区,春玉米在常规施N的基础上减量25%,不仅能维持作物产量,还能有效降低N_2O排放和NO_3~--N的残留。
The effects of nitrogen application on spring maize yield, greenhouse gas emissions and soil nitrate nitrogen (NO_3 - N) residues in rainfed areas were studied through field experiments in three years. The experiment was conducted at the Changwu-Loess Plateau Agro-Ecological Experimental Station, Chinese Academy of Sciences from April 2013 to September 2015. The test crops were spring maize and semi-plastic film mulching. The conventional nitrogen application (N200) and nitrogen application reduction (N150 ) 2 treatments, soil mineral N and nitrous oxide (N 2 O) gas content were measured regularly. The results showed that the yield of maize did not change significantly (P> 0.05), but the average annual yield of N50 was 13.4 (N200) and 13.3 (N150) t · hm -2 ; N150 cumulative N2O emission decreased by 24.3% compared with N200 treatment; N200 treatment 0-200 cm soil profile NO 2 - N residual average 210.2 kg · hm -2, N150 treatment as low as 115.1 kg · hm ~ (-2). There was no significant difference in water consumption during the growth period between N200 and N150 (P> 0.05). In Weibei rainfed farming area, the spring maize is reduced by 25% on the basis of conventional application of N, which can not only maintain the crop yield, but also effectively reduce the N_2O emission and NO_3 ~ -N residual.