Abstract:

[Objective] This study was conducted to assess the soil organic carbon （SOC） contents of five types of alpine deserts and to reveal their regulatory factors. [Method] The alpine desert ecosystems of Qaidam Basin and Gonghe Basin in Qinghai Province were selected as the research objects. A total of 221 soil profile samples were collected using surface investigation method to analyze their SOC contents. In addition, structural equation model was used to reveal the main influencing factors of SOC content. [Result] The SOC contents of the five types of alpine deserts in Qinghai Province exhibited strong heterogeneity. The highest SOC content was observed in chestnut soil, followed by saline soil, brown calcic soil, grey-brown desert soil, and aeolian sandy soil. The SOC contents in chestnut soil and saline soil were significantly （P<0.05） higher than the other three soil types. The pH value of the alpine desert soils had weak heterogeneity, with the order from high to low being aeolian sandy soil, chestnut soil, brown calcic soil, grey-brown desert soil, and saline soil. The SOC content of the alpine deserts was mainly affected by total soil nitrogen content and precipitation, while the pH value was mainly regulated by annual average temperature. [Conclusion] The SOC contents of the alpine deserts in Qinghai Province was relatively higher and had strong heterogeneity, which was mainly attributed to the input of carbon sources from plant roots.

Key words: alpine desert, soil organic carbon, soil type, structural equation model