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| DOI：10.13522/j.cnki.ggps.2025020 |
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| Variation and coupling of soil moisture and soil carbon along an elevation gradient in the region of Western Sichuan, China |
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CAO Shining, LUO Yutian, YU Bohang, ZHAO Yuze, WANG Jianming
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1. School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China;
2. Sichuan Wanglang National Nature Reserve Administration Bureau, Pingwu 622550, China
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| Abstract: |
| 【Objective】Soil carbon and soil moisture are two critical factor influencing ecosystem stability and carbon cycling. This paper studies the variations in soil moisture, organic carbon (SOC) and inorganic carbon (SIC) in soil profiles in the region of Wanglang in Western Sichuan, as well as their interrelationships and underlying mechanisms.【Method】 Soil samples were collected from the 0-15 cm and 15-30 cm soil layers in different locations with an altitude gradient across the region. SOC, SIC, total carbon and soil moisture in the samples were measured. Their spatial distribution pattern and correlation with altitude were analyzed using the Mann-Whitney U tests and the linear regression.【Result】Organic carbon contributed more significantly to total carbon than inorganic carbon in both soil layers. Total carbon was strongly correlated with SOC, with R2=0.998 for the topsoil surface and 0.995 for the subsoil (P＜0.001), but less so with SIC, with R2=0.566 for the topsoil and 0.551 for the subsoil (P＜0.001). SOC, SIC, total carbon and soil moisture were significantly higher in the topsoil than in the subsoil (P＜0.05). Both carbon and soil moisture showed positive correlations with altitude (P＜0.001 for the topsoil and P＜0.05 for the subsoil). In the topsoil, SIC was correlated to soil moisture more significantly (R2=0.421) than SOC (R2=0.403), whereas in the subsoil, SOC showed a stronger correlation with soil moisture (R2=0.611) than SIC (R2=0.375). A positive correlation between SOC and SIC was observed in both soil layers (P＜0.001), suggesting a biogeochemical coupling between them.【Conclusion】Soil carbon in the study area is predominantly composed of organic carbon. Both soil carbon content and soil moisture increase with elevation, though at varying rates. Soil moisture has a stronger influence on SOC than on SIC, indicating greater sensitivity of organic carbon to soil moisture changes. |
| Key words: altitude; soil moisture; soil organic carbon; soil inorganic carbon |
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