不同冬季覆盖作物对稻田甲烷和氧化亚氮排放的影响

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0.20 g·m^-2；冬季作物还田后，各处理早、晚稻田CH4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20.75 g·m^-2；晚稻田CH₄排放量最高的为T₃和T₄处理，分别为58.90和54.51 g·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%.

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

Static chamber-GC technique was employed to study the effects of different treatment winter cover crops, including no-tillage and directly sowing ryegrass (T₁), no0tillage and directly sowing Chinese milk vetch (T₂), tillage and transplanting rape (T₃), no tillage and directly sowing rape (T₄), and fallowing (CK), on the CH₄ and N₂Oemission 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 T₁and T₃not only had the largest CH₄ emission(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, andT₄was larger than that in CK. In early rice field, treatments T₁ and T₂had the largest CH₄emission (21.70 and 20.75 g·m^-2); while in late rice field, treatments T₃ and T₄had the largest one (58.90 and 54.51 g·m^-2, respectively). Treatments T₁-T₄also had larger N₂O emission from earlyand late rice fields than the CK did. The N₂Oemission from early rice field in treatments T₁, T₂, T₃, andT₄ 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.