Effects of land cover types on soil organic carbon stock in alpine meadow

The soil organic carbon (SOC), total nitrogen (TN), particulate organic carbon (POC), light fraction organic carbon (LFOC), carbohydrate, soil organic carbon density were determined on-site under different land cover types with the similar altitude and landform in alpine grassland in Eastern Qilian Mountain. The results showed that SOC and TN changed consistently and performed differently in different land cover types. Soil organic carbon density also performed differently in different land cover types which was highest in grassland (40.42 kg·m-2), moderate in shrub land (32.42 kg·m-2) and lowest in bare land (9.33 kg·m-2) in 0-60 cm depth soil. The content of the POC, LFOC and carbohydrate performed differently in different land cover types, which were highest in grassland, moderate in shrub land and lowest in bare land. With the degrading of alpine grassland to bare land or black beach due to overgrazing, there was an obvious decrease of SOC, TN, POC, LFOC and carbohydrate which result in serious degradation of alpine soil and meadow ecosystem. Therefore, reasonable grazing and regulation of human activities were the effective ways to maintain alpine meadow and achieve sustainable development and social stability of Eastern Tibet Plateau.