Role of soil erosion in biogeochemical nitrogen cycles: a mini review

Soils function as the primary terrestrial reservoirs of essential nutrients, including carbon and nitrogen. The transport and redistribution of soil particles through erosion significantly modify soil properties and nutrient dynamics, thereby profoundly influencing terrestrial biogeochemical processes. Despite substantial advancements in understanding the role of erosion in biogeochemical cycles, the specific effects of erosion on nitrogen cycling across erosional landscapes remain insufficiently characterized. This review synthesizes current knowledge on the impact of soil erosion on nitrogen cycles, with particular emphasis on nitrogen pools, transformation and transport processes, and the underlying mechanisms. Erosion-induced redistribution generally decreases nitrogen stocks in eroding zones and increases accumulation in depositional areas; however, the magnitude and composition of redistributed nitrogen depend on specific erosional conditions. Erosion alters soil physicochemical properties by disrupting aggregates and sorting particles, which negatively affects microbial communities and soil multifunctionality. These changes regulate nitrogen transformation processes, such as mineralization and immobilization. Although most research has focused on hillslope and catchment scales, future investigations should address watershed and regional scales by employing cross-scale approaches, such as integrating regional soil erosion and nitrogen models. Further studies are required to clarify the mechanisms by which erosion influences nitrogen transformation, particularly those involving microbial processes. This review offers insights into the role of soil erosion in biogeochemical nitrogen processes within terrestrial ecosystems.