干旱区生态环境知识资源中心

The inorganic and organic components of soil carbon (C) constitute the largest C pool in the terrestrial biosphere. Determining changes in soil organic C (SOC) and inorganic C (SIC) under different climates is necessary for assessing C sequestration. The effects of arid, semiarid, and semihumid climates on SOC, SIC, and soil total C (STC) storage in 27 pedons along a soil climosequence were investigated. Results showed that SIC constituted 85%, 65%, and 74% of STC in the arid, semiarid, and semihumid regions, respectively, highlighting the importance of inorganic C in the C cycle. Soil organic C and SIC content and storage showed inverse trends with increasing soil depth. The mean content of STC storage in the semihumid region (113.12 Mg ha(-1)) was larger than in the semiarid (62.78 Mg ha(-)1()) and arid (37.49 Mg ha(-1)) regions. The average times needed to store SIC in the semihumid, semiarid, and arid regions were estimated as 15,400, 23,100, and 26,000 years, respectively, suggesting that SIC is storedmore rapidly in wetter climates because of more weathering.