CH4, CO2 and N2O flux among three types of alpine meadow in the north regions of Qinghai-Tibetan Plateau

Greenhouse gas flux from alpine grassland has been one of hotspots to study the relationship between climate change and alpine grassland. Most of these studies focused on gas flux of one type grassland and differences in gas flux among different alpine meadows receives little attention. A experiment was conducted in three types of grassland, ie. alpine meadow, artificial pasture and shrub meadow to investigate the Greenhouse gas fluxes in three types of grassland by using static chambers and gas chromatography. This study indicated that three types of alpine grassland were the sink of atmospheric CH4, and were the source of atmospheric CO2 and N2O. CH4 flux rates were -21.4, -28.1 and -41.1 μg·m-2·h-1 for FC, FCP and GG. CO2 flux rates were 360.6, 447.9 and 475.1 mg·m-2·h-1 for FC, FCP and GG. N2O flux rates were 34.2, 51.6 and 50.6 μg·m-2·h-1 for FC, FCP and GG. CH4, CO2 and N2O flux in growing season accounted for 42.4%～45.6%, 64.1%～67.8% and 37.9%～66.7% of the whole year, respectively. Soil temperature at 5 cm depth negatively correlated with CH4 flux rate (P0.01) and positively correlated with CO2 and N2O flux rate (P0.01). Soil moisture positively correlated with CO2 and CH4 flux rate, negatively correlated with N2O flux rate. Q10 revealed that CO2 flux rate was more sensitive to increase in temperature than CH4 and N2O flux rate. The three grasslands for controlling greenhouse effect were in the following order: GGFCPFC. The CO2 flux rate was much higher than CH4 and N2O flux rate, then contributing an important role to greenhouse effect of grassland.