Distribution characteristics and influencing factors of soil organic carbon in alpine desert ecosystem of Qinghai Province

Alkaline deserts soils acted as important soil pools in arid and semiarid regions. Contents of soil organic carbon (SOC) and its driven factors remained still not clear in alpine deserts on the Tibetan Plateau. In this study, we analyzed 223 soil organic carbon contents and total nitrogen and pH values, and its space distribution pattern under 0-30 cm. It was indicated that average and median SOC were approximate 4.86 and 3.80 g/kg with variation coefficient of 81.14%. SOC contents ranged from 0.54 to 24.34 g/kg. Soils organic carbon contents were divided into four groups. The largest group was around 3.32 g/kg (145 sites) when air temperature and altitude were higher than 1.49 oC and 2793 m. Alpine desert SOC were mainly controlled by total nitrogen (TN) and pH and precipitation with R2 of 0.87 (P<0.001). Furthermore, soil pH was positively affected by air temperature not precipitation (P<0.05). Models may predict SOC through precipitation, air temperature and altitude (R2= 0.40, P<0.001). In addition, increasing regional precipitation perhaps decreased desert soils organic carbon storage in future climate scenarios.