Studies On Emission Fluxes Of CO₂ From Soil-Crop Ecosystem In The Hilly Area Of The Central Sichuan Basin

That the whole globe's climate has been warming and warming was predominant environmental questions and was one of the most talking object. Most specialist thank the most important reasons was emission of the greenhouse gas ,For example CO₂ CH4, N₂O et.al. and the contribution of CO₂ was most biggest. Its proportion was almost 60%. Human activities .especially the burning of coal, petroleum, natural gas and changing land-use or land-cover, released vast CO₂ to atmosphere.Soil-cropping ecosystem was the central part of terrestrial ecosystem and acted important impact in the cycle of biogeochemistry, Escpecially ,in the study of climate and environment, interaction of soil-plant-atmosphere and its affection on climate and ecologysystem had been one of the most research object.Based on the observation of CO₂ emission from soil-crop ecosystems, daily and seasonal variation characteristics, influence factors were discussed in this paper. CO₂ emission was measured by static chamber-gas chromatographic techniques in the hilly area of the central Sichuan Basin. Meanwhile, soil respiration of different plant cover was measured by LI-6400.Results showed:(1) CO₂ emission of Soil-plant ecosystem had obviously dynamic variation ,its affected factors were 5cm soil temperature ,air temperature ,soil moisture, depth of ground surface .growing of crop, physical and chemical characteristic of soil and fertilizers and so on.(2)Soil respiration of up-land wheat and wheat-rice rotation by LI-6400 has similarly daily and seasonal changes.The meanwhile,contribution rate of root respiration and matter decomposed by microorganism from soil by estimated by different ways.(3) Soil respiration rate of up-land wheat was measured by static-chamber and LI-6400 had obvious difference .former was almost 61.76% of latter .The reasons that was their theory of opration was dissimilar.(4) CO₂ emission of Soil-rice ecosystem and soil respiration of soil-maize ecosystem had obviously seasonal variation ,They were affected by environmental factor and factitious factor.Unlike transitions of dissimilar ecosystem had different meanly fluxes and yield.(5) According to dynamic growing of up-land wheat and rape-rice rotation and fluxes of hetero-respiration ,NEP of soil-plant ecosystem could calculated on whole growing season, former was sink of C and latter was resource of C.