Effects of grazing season and degradation degree on the soil organic carbon in alpine meadow

Alpine meadow is the major vegetation type in the Qinghai-Tibet Plateau. This study investigated the differences in soil organic carbon content and storage under different grazing seasons and degradation degree alpine meadow of Qinghai Province. The result of this study showed that soil organic carbon content decreased with the decrease of soil depth from surface to 30 cm depth, and it was not significantly different between cold-season grazing meadow and warm-season grazing meadow at 0―30 cm soil layer. Soil physical properties and biomass at 0-30 cm soil layer varied with different grazing seasons. Soil organic carbon content was the biggest in non-degradation meadow at 0-5 cm layer and in the light-degradation meadow except for 0-5 cm layer. Soil physical properties varied with different degradation stages. The underground biomass increased at first and then decreased while the aboveground biomass decreased as the degradation degree of meadow increased. The soil organic carbon decreased within the cold-season grazing meadow while it increased at first and then decreased in the warm-season grazing meadow. The soil organic carbon density was lower in the cold-season grazing meadow than that in the warm-season grazing meadow but it was not significant. These results implied that the degradation degree played great impact on soil organic carbon.