Effect Of Warming And Nitrogen Addition On Soil Greenhouse Gases Fluxes Of Desert Steppe Ecosystem

Global warming is a big challenge for human and a global problem was generally accepted by international society, and it's an undoubted result, the outcome of global ecosystem brought by global warming is a highlight of ecology. The global warming mainly raised greenhouse gases fluxes. The experiment of controlled warming, nitrogen addition in rain season was conducted under desert steppe ecosystem with infrared heater, and a static box-gas chromatography was used to study the influence of warming and nitrogen addition to soil greenhouse gases fluxes on desert steppe in Inner Mongolia, aiming to get data for global warming, the greenhouse gases emission regularity on desert steppe ecosystem.The results showed as follows.1. Controlled warming significantly increased soil temperature each layer in growth season(P<0.05), and the soil temperature increased 1.14℃,0.75℃,0.55℃,0.68℃and 0.59℃in 0cm,7.5cm,15cm,30cm and 50 cm soil layer,respectively;Except for 7.5cm , nitrogen addition to soil temperature showed negative effect; Their interaction also showed positive effect and warming positive effect was much more than nitrogen addition negative effect.2. Controlled warming significantly enhanced soil water content in each layer, and season change was accorded to the regularity of non-warming plot(P<0.05).3. Soil greenhouse gases fluxes on desert steppe ecosystem generally acted as the source of CO₂ and N₂O, the sink of CH₄. Warming significantly enhanced soil absorption of CH₄ and emission flux of N₂O in desert steppe ecosystem(P<0.05), and there is no significant influence to the emission flux of CO₂(P>0.05). Nitrogen addition had no significant influence to three gases(P>0.05). Interaction of warming and nitrogen significantly increased emission flux of soil N₂O(P<0.05), but had no significant influence on CO₂ and CH₄(P>0.05).4. Daily dynamics variation analysis of soil greenhouse gases emission on desert steppe ecosystem showed that three gases had same change regularity in different treatments and there were no significant differences of three gases daily dynamics in different treatments(P>0.05).