Study On The Soil Microbial Biomass And Greenhouse Gas Emission From Paddy-soil System

Since industrial revolution, greenhouse gases such as CO₂, CH4 and N₂O have rised constantly because of human activity and fossil fuel combustion. A series of serious global environmental problems, such as sea level rising, a variation of precipitation distribution, vegetation and production change, made great challenge on living of human beings and the sustainable development of social economy.Carbon circle in ecosystem is a core topic in the global change study. Carbon circulation in land ecosystem is crucial to predict the content of CO2 and other greenhouse gases in atmosphere in the future, so as to know the interaction between the atmosphere and the biosphere, and it is foundation to know water circulation, nutrient circulation and bio-diversity change in the earth ecosystem.Based on the observation of CO₂, CH₄ and N₂O emission,measured by static chamber-gas chromatographic techniques from different paddy rotation ecosystems, daily and seasonal variation characteristics.Using the static chamber-gas chromatographic techniques,the quatity of CO₂, CH₄ and N₂O from different paddy field rotation ecosystem,daily and seasonal variation aspects in the hilly area of the central Sichuan Basin was determined ,the results were as the following:(1) There was highly significant relation between paddy soil microbial biomass and CO₂, CH₄ and N₂O emission flux from paddy field in autumn, while the correlation between the microbial biomass and the mean plant biomass out-chamber, and fertilizer used parting reached 0.05 and 0.01 level,respectively.(2) Both methanic gas and carbon dioxide emission from rice-rape system , rice-wheat system and winter paddy field varified remarkably seasonally. Methane emission from rice-rape system and winter paddy field was low in the earlier and latter growth stage; while the CO2 emission fluxes from different rotation paddy system rised gradually during the whole growth period.(3) During the rice growth season , methane emission flux from rice-rape system , rice-wheat system and winter paddy field was 11.52, 6.88 and 25.41mg · m^-2 · h^-1 respectively .The mean methane emission flux from winter paddy field was higher than that...