Impact of soil and fluid physicochemical properties on erodibility: a review

Soil surface erosion, a process of removing earth materials such as soils or rocks by flows and/or waves, poses significant threats to the environment, infrastructure, and economy. The erodibility of soil is profoundly influenced by the physicochemical properties of both soil and eroding fluids; however, these effects are not yet fully understood. Therefore, it is essential to establish a clear relationship between these physicochemical factors and soil erodibility. Significant progress has been made over the past few decades in understanding how factors such as temperature, pH, and salt concentration affect soil erosion behaviour. Despite this progress, the results often remain inconsistent and difficult to apply in practice due to variations in research methodologies and an incomplete understanding of erosion mechanisms. This paper reviews and synthesises existing research on the physicochemical effects of soils and fluids on the erodibility of different soil types, addressing these inconsistencies by proposing the Mechanistic Hierarchy Hypothesis, which identifies background salt concentration as the master variable modulating soil sensitivity to secondary drivers like temperature and pH. Furthermore, we discuss recent advancements in sensing technologies that enable high-precision soil–water interface temperature monitoring and erodibility quantification. Finally, this paper outlines practical implications for climate-adaptive infrastructure design and sustainable stabilisation methods, serving as a forward-looking guide for future soil erosion research.