华南丘陵地区农林复合生态系统晚稻田甲烷和氧化亚氮排放

CH_4 and N_2O Emission from Paddy Field of an Agroforestry Ecosystem in the Hilly Area of South China

采用静态箱-气相色谱法对晚稻田甲烷(CH4)和氧化亚氮(N2O)排放进行田间原位测定。结果表明,有植株参与的稻田CH4排放通量季节变化与地下5cm温度呈显著正相关关系。稻田CH4和N2O季节平均排放通量在有植株参与时分别为1.16±0.38mgm-2h-1和42.33±20.00μgm-2h-1,而无植株参与的分别为0.15±0.11mgm-2h-1和51.69±15.87μgm-2h-1。水稻种植对CH4的排放影响较大,对N2O的排放影响较小,有植株参与的稻田CH4平均排放量显著高于无植株参与的稻田,N2O的平均排放量无显著差异。

To quantify the emission of greenhouse gases methane （CH4） and nitrous oxide （N2O） from paddy field of an agroforestry ecosystem in the hilly area in Guangdong, measurements were made with closed static chamber and a modified gas chromatograph （HP5890 Ⅱ） in situ. In this paper, gas samples were taken simultaneously from plot with rice and plot without rice. The seasonal emission of CI-L from plot with rice in the second crop season was significantly correlated to soil temperature at 5 cm depth. Rice plants played a key role in CH4 emission from paddy field. Mean seasonal emission of CH4 and N2O from plot with rice in the second crop season were 1.16±0.38 mg m^-2h^-1 and 42.33±20.00 μg m^-2h^-1, respectively. Mean seasonal emission of CH4 and N20 for plot without rice in the second crop season were 0.15±0.11 mg m^-2h^-1 and 51.69±15.87μg m^-2h^-1, respectively. The results showed that the average seasonal emission of CH4 in plot with rice was significantly higher than that in plot without rice, while no difference in average seasonal emission of N20 was found.