Improving soil thickness estimations and its spatial pattern on hillslopes in karst forests along latitudinal gradients

作者：Zidong Luo, Jinjiao Lian, Yunpeng Nie, Wei Zhang, Fa Wang, Li Huang, Hongsong Chen · 发表于：Geoderma · 年份：2023 · DOI：10.1016/j.geoderma.2023.116749 · 被引用次数：35 · 研究领域：Landslides and related hazards、Soil and Unsaturated Flow、Karst Systems and Hydrogeology

Soils provide storage space for nutrients and water, which governs many hydrological processes and functions in the natural ecosystems. Due to the complex soil-rock structures and localized climate, soil thickness and stock vary distinctly in different karst areas in southwest China. The difficulties of soil detection and the non-transparent underground soil-rock structures limit a deeper understanding of the spatial distribution of soils and their ecological functions. In this study, we employed electrical resistivity tomography (ERT) combined with soil probes to detect the spatial distribution of soils on hillslopes in karst forests in southwest China. The ERT surveys were conducted at six sites with 19 plots (20 × 30 m2) along latitudinal gradients. The results show that the ERT method performs well in visualizing the complex soil–bedrock interfaces and patchy distribution of soils in karst hillslopes, with remarkable consistency with the observed soil thickness and rock outcrops. Soil probes often hit rocks in soils (which we call a “rock barrier effect”), resulting in an underestimation of the mean soil thickness within the one-meter exploration depth by ∼0.18 m. This indicates that soil stock estimates derived from soil probes may be obviously underestimated in karst areas where the rock barrier effects are widespread. Meanwhile, the concept of equivalent soil thickness is proposed to remove the impact of scattered bedrock on soil stock estimation. For the six selected ...