Spatial distributions, driving factors, and threshold effects of soil organic carbon stocks in the Tibetan Plateau

作     者：Sun, Zheng Liu, Feng Yang, Fei Wang, Decai Zhang, Gan-Lin 

作者机构：Chinese Acad Sci Inst Soil Sci State Key Lab Soil & Sustainable Agr Nanjing 211135 Peoples R China Henan Agr Univ Coll Forestry Zhengzhou 450002 Peoples R China Nanjing Hydraul Res Inst Natl Key Lab Water Disaster Prevent Nanjing 210029 Peoples R China Nanjing Hydraul Res Inst Ctr Ecoenvironm Res Nanjing 210029 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Qinghai Normal Univ Sch Geog Sci Key Lab Phys Geog & Environm Proc Qinghai Prov Xining 312366 Peoples R China Chinese Acad Sci Nanjing Inst Geog & Limnol Key Lab Watershed Geog Sci Nanjing 210008 Peoples R China 

出 版 物：《SOIL & TILLAGE RESEARCH》 (Soil Tillage Res.)

年 卷 期：2025年第248卷

核心收录：

学科分类：09[农学] 0903[农学-农业资源与环境] 

基　　金：National Natural Science Foundation of China [42071072, 41930754] National Key Basic Research Special Foundation of China [2014FY110200] The "14th Five-Year Plan" Autonomous Deployment Project of the Institute of Soil Science, Chinese Academy of Sciences [ISSASIP2202] 

主　　题：Digital soil mapping Carbon pools Quantile regression forest Generalized additive model 

摘      要：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.