不同冬季覆盖作物对稻田甲烷和氧化亚氮排放的影响

Effects of winter cover crop on methane and nitrous oxide emission from paddy field

采用静态箱-气相色谱法对不同冬季覆盖作物处理[免耕直播黑麦草-双季稻(T1)、免耕直播紫云英-双季稻(T2)、翻耕移栽油菜-双季稻(T3)、免耕直播油菜-双季稻(T4)和冬闲-双季稻(CK)]下稻田甲烷(CH4)和氧化亚氮(N2O)排放进行观测,分析了不同冬季覆盖作物对稻田CH4和N2O排放的影响.结果表明:在冬季作物生长期,不同冬季覆盖作物稻田CH4和N2O总排放量与对照(CK)的差异均达到极显著水平(P<0.01);T3和T1处理的稻田CH4和N2O排放量最高,其CH4排放量分别为0.88和0.60g·m-2,N2O排放量分别为0.23和0.20g·m-2;冬季作物还田后,各处理早、晚稻田CH4排放量均明显高于对照.早稻田CH4排放量最高的为T1和T2处理,分别达21.70和20.75g·m-2;晚稻田CH4排放量最高的为T3和T4处理,分别为58.90和54.51g·m-2.各处理早、晚稻田N2O总排放量均显著高于对照,T1、T2、T3和T4处理的早稻田N2O总排放量分别比对照增加53.7%、12.2%、46.3%和29.3%,晚稻田分别比对照增加28.6%、3.8%、34.3%和27.6%.

Static chamber-GC technique was employed to study the effects of different treatment winter cover crops,including no-tillage and directly sowing ryegrass （ T1） ,no-tillage and directly sowing Chinese milk vetch （ T2） ,tillage and transplanting rape （ T3） ,no-tillage and directly so-wing rape （ T4） ,and fallowing （ CK） ,on the CH4 and N2O emission from double cropping rice paddy field. During the growth period of test winter cover crops,the CH4 and N2O emission in treatments T1-T4 was significantly higher than that in CK （ P 0. 01） . Treatments T1 and T3 not only had the largest CH4emission （ 0. 60 and 0. 88 g·m -2） ,but also had the largest N2O emission （ 0. 20 and 0. 23 g·m-2,respectively） . After the winter cover crops returned to field,the CH4 emission from early and late rice fields in treatments T1,T2,T3,and T4 was larger than that in CK. In early rice field,treatments T1 and T2 had the largest CH4 emission （ 21. 70 and 20. 75 g·m -2） ; while in late rice field,treatments T3 and T4 had the largest one （ 58. 90 and 54. 51 g·m-2, respectively）. Treatments T1-T4 also had larger N2O emission from early and late rice fields than the CK did. The N2O emission from early rice field in treatments T1,T2,T3,and T4 was increased by 53. 7% ,12. 2% ,46. 3% ,and 29. 3% ,and that from late rice field in corresponding treatments was increased by 28. 6% ,3. 8% ,34. 3% ,and 27. 6% ,respectively,compared with CK.