CH4 and N2O Emission from Paddy Field of an Agroforestry Ecosystem in the Hilly Area of South China

Abstract:

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 CH₄ 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.