麦秸还田与土壤耕作对稻季CH_4和N_2O排放的影响

2008年在大田试验条件下,设置麦秸还田旋耕、麦秸不还田旋耕、麦秸还田翻耕、麦秸不还田翻耕4个处理,采用静态暗箱-气相色谱法田间原位观测稻麦两熟制农田水稻生长季CH_4和N_2O排放通量,研究小麦秸秆全量还田与土壤耕作两项技术措施对稻季CH_4和N_2O排放的影响及其温室效应,以期为稻麦两熟制农田温室气体减排提供对策.结果表明:麦秸还田对稻季CH_4排放总量的影响达极显著水平,麦秸还田与耕作方式的互作效应对CH_4排放总量有显著影响,麦秸还田和耕作方式对N_2O排放总量的影响均达极显著水平;不同麦秸还田与土壤耕作处理稻季OH4排放总量为:麦秸还田旋耕>麦秸还田翻耕>麦秸不还田翻耕>麦秸不还田旋耕,N_2O的排放总量为:麦秸不还田翻耕>麦秸不还田旋耕>麦秸还田翻耕>麦秸还田旋耕;与麦秸不还田相比,相同耕作措施下麦秸还用排放CH_44和N_2O所产生的全球增温潜势(GWP)明显提高.麦秸还田条件下旋耕处理的GWP高于翻耕处理,而"单位产量的GWP"无明显差异,麦秸不还田条件下采用旋耕措施较翻耕可减轻温室效应.

Effects of wheat straw returning and soil tillage on CH_4 and N_2O emissions in paddy season

A field experiment was conducted in 2008 to investigate the effects of wheat straw returning and soil tillage on CH_4 and N_2O emissions in paddy season in a wheat-rice double cropping system by using the method of static chamber-gas chromatographic techniques. Four treatments(i.e. wheat straw returning + rotary tillage, SRT; wheat straw returning + conventional tillage, SCT; no wheat straw returning + rotary tillage, RT; no wheat straw returning + conventional tillage, CT) were implemented in this experiment. Results showed total CH_4 emissions were significantly influenced by wheat straw returning treatments, the interaction between wheat straw returning and soil tillage treatments on total CH_4 emissions was significant. The total N_2O emissions within four treatments were significantly different. The order of the total CH_4 emissions was SRT > SCT > CT > RT, and the order of the total N_2O emissions was SCT > SRT > CT > RT. As comparing with no wheat straw returning treatments under the same soil tillage, wheat straw returning significantly increased the total global warming potential(GWP) of CH_4 and N_2O emissions. Relative to SCT, SRT increased GWP, but there is no obvious difference in GWP per yield between SCT and SRT. In contrast with CT, RT effectively decreased greenhouse effect.