Shuitu baochi tongbao (Feb 2023)
Spatial Variation Characteristics and Influencing Factors of Soil Organic Carbon in a Rocky Beach of Sejila Mountain, Tibetan Plateau
Abstract
[Objective] The characteristics of surface soil soluble organic carbon (DOC), readily oxidized organic carbon (ROC), carbon pool stability, and carbon storage changes, as well as influencing factors of soil organic carbon (SOC) and DOC at different elevations in Tibetan Plateau were analyzed in order to provide a scientific basis for subsequent research on the stability of SOC in cold regions with complex terrain. [Methods] Data were collected from a rocky beach of the Sejila Mountain. One-way ANOVA was used to analyze soil physical properties and DOC, ROC, and SOC content characteristics at altitudes ranging from 4 300 m to 4 700 m. Pearson correlation analysis and redundancy analysis were used to determine the relationship between DOC, ROC, and influencing factors. [Results] ① Soil bulk density and dry density were negatively correlated with altitude, and their maximum values were 1.56 g/cm3 and 1.12 g/cm3, respectively. Soil water content and porosity were positively correlated with altitude, and the maximum values were 74.22% and 58.70%, respectively. ② SOC content initially increased with increasing altitude and then decreased. DOC and ROC showed fluctuating trends with elevation. ③ DOC/SOC and ROC/SOC reached maximum values at 4 400 m. The average DOC and SOC values were 40.779 kg/m2 and 8.105 kg/m2, respectively. The stability of the soil carbon pool in the rocky beach area was relatively good. ④ DOC had no correlation with soil physical properties, but was correlated with average SOC. ROC was correlated with physical properties, SOC, and its related factors. Each factor was correlated with changes in DOC and ROC in the rocky beach area of the Sejila Mountains. Explanatory contribution rate follow the order of average DOC>soil porosity>ROC/SOC>soil water content>SOC>average SOC>DOC/SOC>soil dry density. [Conclusion] Soil DOC and ROC at different elevations were correlated, and average DOC, soil porosity, and ROC/SOC were important factors affecting the contents of DOC and ROC. There were close relationships among these factors.
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