沼泽湿地CO_2、CH_4、N_2O排放对氮输入的响应

CO_2,CH_4 and N_2O emissions to the atmosphere upon nitrogen addition in the swamp wetland

利用静态暗箱气象色谱法,选取小叶章沼泽化草甸进行野外原位试验,研究氮输入对沼泽湿地CO2、CH4和N2O等3种温室气体排放的影响.结果表明:氮输入对沼泽湿地CO2和CH4排放有明显影响,其季节排放总量分别是对照处理的1.3和2.5倍,但对CO2和CH4的季节变化模式无明显影响;氮输入对N2O的排放强度和季节变化模式均有显著影响.CO2排放通量与5cm深土壤温度存在显著的正相关关系,与地表温度和1.5m气温存在指数关系,而CH4和N2O排放与温度之间没有显著的相关性.在20、100和500年时间尺度上氮输入处理的CH4和N2O全球增温潜势(GWP)分别比对照处理增加了150%、150%和80%,表明氮输入在长、短时间尺度上都是增强CH4和N2O的温室效应的.

By using the static opaque chamber-GC techniques, the influence of nitrogen addition in situ on emissions of CO2, CH4 and N2O from Doyeuxia angustifolia wetland was studied. The results showed that there were no significant differences in patterns of seasonal variations of CO2 and CH4 among the treatments, but the CO2 and CH4 emission with nitrogen addition treatment increased 30% and 150% respectively compared to the control treatment. However, both the seasonal pattern and emissions of the N2O were significantly affected by the nitrogen addition. The CO2 flux increased with the increase of the temperature, and there was no significant statistical correlation between the CH4 flux and temperature, so is the N2O. On long time scale of 20, 100, and 500-year period, the integrated global warming potential （GWP） of CH4 ＋ N2O released during the growing season for the treatments of nitrogen addition was 150% , 150% and 80%, respectively, higher than that for the control treatment, which suggested that the nitrogen addition could enhance the GWP of the CH4 and N2O either in long time or short time scale.