亚热带稻田生态系统CO_2排放及影响因素

CO_2 emission from the paddy ecosystem in subtropical region and its influence factors.

采用静态箱法对亚热带稻田生态系统CO2排放进行了定位观测.结果表明,水稻生长条件下的稻田CO2总排放通量(Rt)随晚稻生育期进程波动幅度较大,平均值为926.2mg/(m2·h);土壤CO2排放通量(Rs)则波动较小,平均值为285.4mg/(m2·h).二者与气温、不同土层(0,5,10,15cm)土壤温度均呈极显著的指数相关关系,温度系数(Q10)分别为2.33和1.70.稻田生态系统CO2累积排放量与水稻生物量间存在极显著的对数关系.在晚稻整个生育期,稻田生态系统从大气中净固定碳量为3.85t/hm2.

The orientational observation of CO2 emission from paddy ecosystem in subtropical region was carried out, adopting closed static chamber technique. Under the growth condition of paddy rice, the total emission flux (Rt) of paddy CO2 had greater fluctuation in the growth course of late rice, with an average value of 926.2 mg/(m2·h). The soil CO2 emission flux (Rs) had small fluctuation, with an average value of 285.4 mg/(m2·h). Both fluxes appeared marked exponential relationships with air temperature and soil depth (0, 5, 10, 15 cm). The temperature coefficients (Q10) were 2.33 and 1.70 respectively. There was a very marked logarithmic relationship between CO2 accumulative emission amount of paddy ecosystem and rice biomass. During the entire growing period of late rice, the net carbon amount of paddy ecosystem fixed from atmosphere was 3.85 t/hm2.