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Spatial distributions, driving factors, and threshold effects of soil organic carbon stocks in the Tibetan Plateau
Soil and Tillage Research ( IF 6.1 ) Pub Date : 2025-01-21 , DOI: 10.1016/j.still.2025.106457
Zheng Sun, Feng Liu, Fei Yang, Decai Wang, Gan-Lin Zhang

The Tibetan Plateau (TP), known as the “Earth's Third Pole”, has a fragile ecological environment, and is sensitive to global changes, which can easily lead to fluctuations of soil organic carbon (SOC). The spatial variations of soil organic carbon stocks (SOCS), and their driving factors in TP remain unclear. Here. we used quantile regression forest (QRF) model to map soil organic carbon density (SOCD) in TP at 90 m spatial resolution, and estimated the spatial uncertainty of the mapping. Generalized additive model (GAM) was used to analyze the nonlinear responses of SOCD to the driving factors. The results showed that the QRF model can explain about 32 %–51 % of SOCD variation, and the explanatory power decreased with increasing depth. The SOCD decreased gradually from southeast to northwest, and showed a decreasing trend with increasing depth. The SOCS of 0–100 cm soil was 37.26 Pg C of the entire TP, where the grassland occupied 54.59 % of the total stock. Vegetation and land surface temperature were important environmental covariates at all depths. SOCD has obvious nonlinear responses and threshold effects on temperature (MAAT), precipitation (MAP) and aridity (1–AI). The results are of great significance for understanding the status of SOC sequestration, and the response of SOCS in TP to climate conditions.

中文翻译:


青藏高原土壤有机碳储量的空间分布、驱动因素及阈值效应



被称为“地球第三极”的青藏高原 (TP) 拥有脆弱的生态环境,对全球变化敏感,很容易导致土壤有机碳 (SOC) 的波动。土壤有机碳储量 (SOCS) 的空间变化及其对 TP 的驱动因素尚不清楚。这里。我们使用分位数回归森林 (QRF) 模型在 90 m 空间分辨率下绘制 TP 中的土壤有机碳密度 (SOCD),并估计映射的空间不确定性。广义加性模型 (GAM) 用于分析 SOCD 对驱动因素的非线性响应。结果表明,QRF 模型可以解释约 32 %–51 % 的 SOCD 变化,解释力随着深度的增加而降低。SOCD 由东南向西北逐渐降低,并随深度的增加呈下降趋势。0–100 cm 土壤的 SOCS 为整个 TP 的 37.26 Pg C,其中草原占总存量的 54.59%。植被和地表温度是所有深度的重要环境协变量。SOCD 对温度 (MAAT) 、降水 (MAP) 和干旱度 (1-AI) 具有明显的非线性响应和阈值效应。研究结果对于理解青藏高原土壤有机碳封存状况以及青藏高原土壤有机碳对气候条件的响应具有重要意义。
更新日期:2025-01-21
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