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以位于西南大学农业部重庆紫色土生态环境重点野外科学观测试验站内的稻-油轮作农田为研究对象,采用静态暗箱/气相色谱法,对覆膜与常规(不覆膜)两种处理下稻-油轮作农田CH_4和N_2O的排放特征及影响因素进行了为期一年的原位观测.结果表明,两种处理下,CH_4和N_2O的排放均主要集中在各作物的生长前期,水稻季CH_4和油菜季N_2O的排放通量均具有较明显的季节变化;全年CH_4的排放通量介于-0.45~1.90 mg·(m~2·h)~(-1),N_2O的排放通量介于-46.1~2 040.7μg·(m~2·h)~(-1).地膜覆盖提高了CH_4和N_2O排放总量,其中覆膜处理全年CH_4排放总量为(27.22±4.48)kg·hm~(-2),相比常规处理(19.93±0.56)kg·hm~(-2)提高了26.22%;覆膜处理N_2O的年排放总量为(13.14±0.82)kg·hm~(-2),较常规处理下(11.27±2.77)kg·hm~(-2)增加了16.6%.覆膜显著提高了油菜季土壤含水率,而对全年各作物季土壤温度(地下5 cm温度和地表温度)没有明显的影响.覆膜处理下油菜季CH_4和N_2O的排放与土壤含水率呈负相关,幼苗期达显著负相关;两种处理下,各作物季CH_4和N_2O的排放与土壤温度的相关性均很小.研究表明,地膜覆盖影响作物各生育期内CH_4和N_2O的排放规律,改变了作物各生育期内2种气体排放占全季排放量的比例,促进了稻-油轮作农田CH_4和N_2O的排放.在100 a时间尺度上,覆膜处理下全年排放的CH_4和N_2O所引起的综合GWP(CO_2量)为4 213.00 kg·hm~(-2),较常规处理3 454.17 kg·hm~(-2)提高了22.0%,表明覆膜不是一种有效的碳减排措施.
Taking paddy field-rice crop rotation farmland located in Key Laboratory of Purple Soil Ecology Environment of Chongqing Agricultural University located in Southwest University as the research object, static black box / gas chromatography was used to study the effects of both the coating and the conventional The results showed that the emission of CH 4 and N 2 O mainly concentrated in the early growth stage of each crop, and the CH 4 and N 2 O emissions of rice crop The emission fluxes of N_2O in rapeseed season all had obvious seasonal changes. The annual CH_4 emission flux ranged from -0.45 to 1.90 mg · (m ~ 2 · h) -1, and the emission flux of N_2O was between -46.1 ~ 2040.7μg · (m ~ 2 · h) -1. Mulching increased the total amount of CH_4 and N_2O, and the total amount of CH_4 emission during the whole year was (27.22 ± 4.48) kg · hm ~ (-2), which was increased by 26.22% compared with that of conventional treatment (19.93 ± 0.56) kg · hm -2, and the annual emission of N 2 O was (13.14 ± 0.82) kg · hm -2 ), Which was increased by 16.6% compared with that of conventional treatment (11.27 ± 2.77 kg · hm -2). Mulching significantly increased the soil water content of rapeseed season, but the soil temperature (5 cm underground temperature and Surface temperature) Had a significant effect on the rapeseed season.The emission of CH_4 and N_2O in the rapeseed season was negatively correlated with the soil water content and significantly negatively correlated with the seedling stage.The correlation between CH_4 and N_2O emissions and soil temperature The results showed that the plastic film mulching affected the emission of CH 4 and N 2 O during the whole growth period of crops and changed the ratio of the emission of 2 gases to the total amount of the whole crop during each growth period of crops and promoted the growth of CH_4 and N 2 O. The total GWP (CO 2 content) caused by CH 4 and N 2 O released during the whole year under the film mulching treatment was 4 213.00 kg · hm -2 on the 100 a time scale, which was 3 454.17 kg · hm ~ (-2) increased by 22.0%, indicating that the film is not an effective carbon reduction measures.