Variation and Influencing Factors of Soil Organic Carbon Across an Alpine Desert Ecosystem of Tibetan Plateau

Abstract

Deserts soils acted as important soil carbon pools in arid and semiarid regions. Soil organic carbon (SOC) contents and its driven factors remained unclear in alpine deserts on the Tibetan Plateau. In this study, we sampled 223 soil profiles, and analyzed SOC values under 0-30 cm. It was indicated that average and median of SOC were approximately 4.86 and 3.80 g/kg. SOC contents were divided into four groups. The largest group was approximately 3.32 g/kg (145 profiles, P<0.05) when air temperature and altitude were higher than 1.49ºC and 2793 m with lower precipitation of 173.4 mm encircling with Qaidam basin. Future increasing precipitation scenario would be an effective countermeasure to increase SOC in this region. Furthermore, SOC of the smallest group was 13.7 g/kg when precipitation was over 371.5 mm in the south of Qinghai Lake. Alpine desert SOC were mainly controlled by total nitrogen and pH and precipitation with R2 of 0.87 (P<0.001). In addition, increasing nitrogen deposition and mineral decomposition significantly increased desert soils organic carbon storage.