Both soil organic carbon (SOC) and inorganic carbon (SIC) are important components of soil carbon storage. However, few studies have attempted to estimate the magnitude and patterns of SIC in arid areas. We measured the concentrations of SOC and SIC in alpine steppe grasslands along a climate gradient in the Tibetan Plateau. At all sites, an opposing trend was found in the distribution of SOC compared with SIC. SOC increased with increasing precipitation, while SIC decreased. Within sites, SOC decreased with soil depth, while SIC increased. Among the variables considered, soil total nitrogen (TN) and soil water content explained the most variability in SOC (r² = 0.95 for TN, r² = 0.93 for soil water content), and soil pH had the highest correlation with SIC (r² = 0.90). This finding indicates that SOC is closely related to biological processes, such as biomass input and litter accumulation, while SIC is determined by abiotic factors such as chemical and physical processes of soil formation. SOC and SIC densities showed that the SOC pool comprised 91% of total carbon (TC) storage in these alpine steppe soils. A decrease in SOC density occurred with depth, but this pattern was the opposite for SIC density in all soil profiles. These findings help to characterize the C cycle in the alpine steppe of the Tibetan Plateau.

土壤有机碳（SOC）和无机碳（SIC）都是土壤碳存储的重要组成部分。但是，很少有研究试图估计干旱地区SIC的规模和格局。我们测量了青藏高原沿气候梯度的高寒草原草地上SOC和SIC的浓度。与SIC相比，在所有站点上，SOC的分布都呈现出相反的趋势。SOC随着降水增加而增加，而SIC则下降。在场地内，SOC随土壤深度而降低，而SIC则升高。在考虑的变量中，土壤总氮（TN）和土壤水分解释了SOC的变化最大（TN的r ²  = 0.95  ，土壤水分的r ² = 0.93），并且土壤的pH与SIC的相关性最高（r ^2个 = 0.90）。这一发现表明，SOC与生物过程（例如生物量输入和垫料积累）密切相关，而SIC则由非生物因素（例如土壤形成的化学和物理过程）决定。SOC和SIC密度表明，在这些高山草原土壤中，SOC库占总碳（TC）储量的91％。SOC密度随深度而降低，但在所有土壤剖面中，SIC密度均相反。这些发现有助于表征青藏高原高山草原的碳循环。