秸秆条带状覆盖对稻田CH4和N2O排放的影响

CH_4 AND N_2O EMISSIONS FROM RICE FIELDS AS AFFECTED BY MULCHING OF STRIPS OF WHEAT STRAWS

采用3种秸秆还田方式(对照、秸秆均匀混施和秸秆条带状覆盖)进行田间试验,观测稻田CH4和N2O的排放通量,以探讨秸秆条带状覆盖对稻田CH4和N2O排放的影响。结果表明:秸秆条带状覆盖的CH4排放量是对照的2.7倍,二者的N2O排放量无明显差异;秸秆条带状覆盖的稻田CH4排放量较秸秆均匀混施减少32%,其N2O排放量是后者的5.1倍;稻田排放CH4和N2O的全球增温潜势(GWP)为:秸秆均匀混施>秸秆条带状覆盖>对照,且差异显著;秸秆条带状覆盖的水稻产量分别较对照和秸秆均匀混施增加27%和17%。秸秆条带状覆盖是值得推荐的稻季秸秆还田方式。

A field experiment was conducted in 2006 to monitor CH4 and N2O emissions from rice fields as affected by strip mulching of wheat straws. The experiment was designed to have three treatments, i.e. （i） no wheat straw applied （Treatment CK） ; （ii） incorporating wheat straws evenly into the topsoil （Treatment WI） ; and （iii） strip mulching of wheat straws over the field （ Treatment WM）. Results show that compared with Treatment CK, Treatment WM significant- ly increased CH4 mission by 2.7-fold. No significant difference in N20 emission was observed between Treatments CK and WM. Compare with Treatment WI, Treatment WM decreased CH4 emission significantly by 32% , while enhancing N2O emission by 5. 1-folds. The GWP of ca4 and N2O emitted from rice field was greatest in Treatment WI, which was followed by Treatments WM and CK, and the differences between them reached significant level. Compared with Treatments CK and WI, Treatment WM increased rice grain yield by 27% and 17% , respectively. Based on these results, the best management of wheat straw prior to rice cultivation is mulching of strips of wheat straws over the field.