Soil CO2,CH4 and N2O Fluxes from Alpine Meadows on the Plateau of Southern Qinghai Province During Snow Cover Period and Growing Seasons

Abstract

To understand the fluxes of soil greenhouse gases from Alpine meadows on the Qinghai-Tibet plateau during non-growing season, a static chamber method was used to sample gases of soil CO2, CH4 and N2O from alpine meadow on the plateau of Southern Qinghai province during snow cover period, and gas chromatography was used to analyze concentrations of these gases. The results showed that soil CO2 flux was 1.33 g·(m2·h)-1, soil CH4 flux was -0.19 mg·(m2·h)-1, and soil N2O flux was 0.21 mg·(m2·h)-1 when the snow depth was 9-10 cm on March 3 and 4 during the prevalence period of snow cover; soil CO2 flux was 4.70 g·(m2·h)-1 ,and soil N2O flux was 0.24 mg·(m2·h)-1, and soil CH4 flux was -1.23 mg·(m2·h)-1 when the snow depth was 8-9 cm on April 30 during the end period of snow cover. And soil CO2 and N2O fluxes were low or negative, soil CH4 flux was negative and its absolute value was low when the snow depth was less than 4 cm during snow cover period. In addition, soil CO2 or N2O flux was positively correlated with the snow depth, and soil CH4 flux was negatively correlated with the snow depth (P<0.05). Additionally, soil CO2 or N2O flux was negatively correlated with CH4 fluxes, and soil CO2 was positively correlated with soil N2O flux. In addition, soil CO2 flux was the highest during the growing season, followed by the end period of snow cover, and it was the lowest during the prevalence period of snow cover; soil N2O flux was high during the growing season, followed by the end period of snow cover, and it was the lowest during the prevalence period of snow cover; soil CH4 flux was negative, and its absolute value was higher during the growing season than other seasons, and it was the lowest during the prevalence period of snow cover. The results suggested that the change in snow cover would influence the fluxes of soil greenhouse gases from alpine meadow on the Qinghai-Tibet plateau.