Effects of water table changes on soil CO_2, CH_4 and N_2O fluxes during the growing season in freshwater marsh of Northeast China

摘要

A field control experiment was carried out to determine the influence of water table changes on soil CO_2, CH_4, and N_2O emissions in Calamagrostis angustifolia freshwater marsh in Northeast of China. The results showed that the water depth of 5 cm below the ground surface increased soil CO_2 emission, but there was no significant influence of deeper water table on gas emission. CH_4 emission was accelerated by deep standing water and approached the peak in the plant booming time. This suggests that root activity has influence on CH_4 production. The result also demonstrated that both low water table level and inundated environment would inhibit N_2O emission. Comparing the total global warming potential of three gases under different conditions, it can be concluded that maintaining a comparatively steady water table near the soil surface can benefit soil carbon sequestration in the C. angustifolia marsh, and decrease of the greenhouse gases emissions to the atmosphere.