三江平原稻田N_2O通量特征

Characteristics of N_2O Fluxes in Paddy Fields of the Sanjiang Plain

利用静态暗箱-气相色谱法于2004年11月—2005年10月对三江平原稻田进行了全年连续田间原位观测。结果表明,三江平原稻田全年N2O平均通量为0.052mg·m-·2h-1;冻融期N2O通量范围为0.008～0.029mg·m-·2h-1,融冻时排放量显著增加;生长期平均通量为0.059mg·m-·2h-1,施肥后及淹水期间水面落干时各出现了两个明显的N2O排放峰,排水后N2O排放通量较淹水期稍增加,但幅度不大。同时分析了冻融期、生长期N2O通量季节变化特征和日变化特征以及和相关环境因子的关系,分析表明,温度决定了稻田全年N2O排放通量的大小,而水分状况则是影响三江平原稻田N2O排放季节变化特征的主要因素。

Nitrous oxide （N20） emission from paddy field was observed by static-closed-chamber and GC （Agilent 4890） through the continuous experiment from 2004.11 to 2005.10 in the Sanjiang Plain. The results showed that the annual mean flux of N20 was 0.052 mg·m^-2·h^-1 and the mean flux during the growing season was 0.059 mg·m^-2·h^-1. The N20 flux increased significantly during the thawing and ranged from 0.008mg·m^-2·h^-1 to 0.029 mg·m^-2·h^-1 during freezing and thawing. Two humps appeared after fertilization and the other two appeared when the water level declined during the growing period. N2O flux increased slightly after drainage. The seasonal and diurnal variations of N2O flux were analyzed. The analysis of relationship between N2O flux changes and environmental factors showed that temperature was the determinative factor that influenced the mean annual N2O flux, while water management was the main factor that influenced the seasonal variation of N20 flux in the paddy field of SanJiang Plain.