Abstract: Through two years located field observation,this paper studied the responses of marsh soil temperature to air temperature and the effects of soil temperature on CO₂ emission from marsh soil-vegetation system,and calculated the seasonal variation of CO₂ emission.The results showed that from the beginning of thawing,an increasing trend of soil temperature was exerted by the change of air temperature,and there was a significant exponential correlation between soil temperature in root layer and air temperature (R²=0.94,P<0.01).Despite of the decreased responses of soil temperature to air temperature with increasing soil depth,the CO₂ emission from marsh soil-vegetation system was strongly exponentially correlated with soil temperature in root layer (R²=0.84,P<0.01).An improved model equation was used for calculating the mean CO₂ efflux from marsh soil-vegetation system during the growth season in 2003,and the calculated CO₂ efflux was 664.5±213.9 mg·m^-2·h^-1,approaching the value of located field observation (634.0±227.7 mg·m^-2·h^-1),indicating that this model equation was effective to evaluate the CO₂ emission from marsh during growth season.

Key words: N₂O emission, Fertilising, Tilling, Upland soils, DNDC model