A review of impacts of soil rock fragments on slope erosion: Mechanism and processes

Rock fragments play a pivotal role in influencing slope erosion processes, attracting increasing scientific interest and growing concerns regarding their potential impacts on erosion. This paper reviews the studies published in recent decades concerning the various impacts of rock fragments on soil erosion processes by water, highlighting the research gaps and outstanding challenges in exploring the erosion evolution process involving rock fragments. Systematic studies and illustrative examples have shown that the impacts of rock fragments characteristics (such as coverage, content, size, position, shape, and spatial heterogeneity) on erosion processes are complex and inconsistent (positive/negative). This uncertainty can be attributed to the intricate erosion process and the diverse rock fragment characteristics, complicating the development of accurate erosion prediction models. Current models predominantly focus on rock cover and often ignore the essential factors including rock size, position, and shape, thus impeding the precise understanding of how rock fragment characteristics specifically affect soil erosion within existing erosion models. Furthermore, this review discusses the perspectives for enhancing the research on rock fragment impacts on soil erosion processes and provides insights into potential research requirements and solutions.