Short term effect of precipitation amount change on greenhouse gas emissions from alpine grassland in the eastern Qinghai-Tibetan Plateau

The effects of a change in the precipitation amount on greenhouse gases (GHGs) emission from the alpine grassland ecosystem have not yet to be elucidated. In this research, the GHGs (CO2, CH4 and N2O) fluxes in the eastern Qinghai-Tibetan Plateau were measured with an artificially increased precipitation (increase of 200 mm) and a decreased precipitation (decrease of 200 mm) by using the static chamber meteorological chromatography method in a growing season (from May to September). Under both increased precipitation (IP) and decreased precipitation (DP) experimental treatments, the alpine grassland functioned as the source of CO2 and N2O and as the CH4 sink. Compared to the control check (CK), the IP slightly enhanced the average CO2 and N2O emission fluxes by 4.2% (P>0.05) and 17.2% (P>0.05), respectively, but it declined the average CH4 absorption flux by 21.9% (P<0.05). In contrast, the DP decreased the average CO2 emission fluxes by 10.2% (P<0.05), slightly enhanced the average N2O emission fluxes by 4.6% (P>0.05), and increased the average CH4 absorption flux by 15.9% (P<0.05).