为了解氮肥运筹和秸秆还田对麦田土壤温室气体排放的影响,在秸秆还田条件下设置基肥∶壮蘖肥∶拔节肥∶孕穗肥为3∶1∶3∶3(N1)、5∶1∶2∶2(N2)、7∶1∶2∶0(N3)三个氮肥运筹方式,在秸秆不还田条件下设置5∶1∶2∶2一个氮肥运筹方式(N4),采用静态暗箱-气相色谱法对不同处理下麦田土壤排放的二氧化碳(CO2)、甲烷(CH4)和氧化亚氮(N2O)进行观测,测定小麦籽粒产量,估算土壤温室气体排放强度(GHGI)和麦季全球增温潜势(GWP)。结果表明,与秸秆不还田相比,秸秆还田显著促进了麦季CH4和CO2的排放,显著降低了N2O的排放,显著提高了麦季GWP。秸秆还田条件下,不同氮肥运筹方式间CH4、CO2累积排放量和GWP差异不显著,但N3处理显著提高了N2O累积排放量,分别较N1、N2处理提高61.22%、51.92%。N1、N2处理的GHGI最低,分别较N4处理降低41.27%和39.67%,N3处理的GHGI较N4处理增加3.30%。因此,麦季秸秆还田下采用3∶1∶3∶3和5∶1∶2∶2氮肥运筹方式有显著地增产与综合减排作用,是低碳生产的合理施肥措施。
A field experiment was conducted to investigate the effects of straw returning with different application ratios of nitrogen [3 : 1 : 3 : 3(N1),5 : 1 : 2 : 2(N2),7 : 1 : 2 : 0(N3)] and no straw re- turning with 5 : 1 : 2 : 2 nitrogen application ratio(N4) on the emissions of CH4 ,CO2 and N20. Com- bined with the yield,greenhouse gas intensity(GHGI) and global warming potential(GWP) were esti- mated. Gas fluxes were analyzed using the static opaque chamber gas chromato-graphy method. Com- pared with no straw returning, rice straw returning significantly increased the emissions of CO2 and CH4 ,hut decreased N2O emission, and increased GWP during wheat growing season. No significant difference was noted between the cumulative emissions of CH4 and CO2 and GWP under different ni- trogen application ratios. However,the N3 treatment significantly increased the cumulative emission of N2O,with an increase of 61.22% and 51.92%,compared with N1 and N2. The GHGI of N1 and N2 was decreased by 41.27% and 39.67%,compared with N4. The GHGI of N3 was 3.30% higher thanthat of N4. Our study indicated that the nitrogen application ratios of 3 :1 : 3 : 3 significant effects on reducing greenhouse gas emission and could be used as an carbon production of wheat. and5: 1: 2: 2had effective way of low