Water erosion and its mitigation in sloped black soil farmlands in Northeastern China: A review

【Background and Objective】 Water erosion is a common form of soil degradation, affecting 1.071 4 million km2 of soil in China, accounting for 40.77% of national soil erosion. While the soil surface in most regions in Northeastern China is relatively flat, the black soils are susceptible to water erosion due to their unique environment and unsustainable agricultural practices, threatening food production and ecological security. Tremendous efforts have been made in improving the black soil and water conservation to ameliorate water erosion. This paper reviews the progress made over the past decades. 【Method】 The review was based on literature and data related to water erosion in sloped black soils and their mitigation technologies, with the focus on the influence of rainfall, topography, vegetation, soil condition and human activities. 【Result】 The area of soils affected by water erosion was approximately 133 200 km2, accounting for 63.76% of total eroded black soils in the region. Hillslope and gully erosion are the predominant erosion patterns, forming a hillslope-gully system that is a major source of sediment. Key erosion-control technologies included ridge tillage, straw return, ridge planting, hedgerows, terracing, minimal tillage with residue mulching, no-tillage, and gully control. Critical issues in implementing these technologies include a detailed understanding of their underlying mechanisms, effectiveness, optimal configurations, and selection for different regions. Future research should focus on improving understanding of the mechanisms of these technologies, establishing a comprehensive erosion-control system, and developing strategies for regulating runoff and soil consolidation. 【Conclusion】 Water erosion is a great challenge in sloped black soil farmland in Northeastern China, influenced by both natural factors and human activities. Significant efforts have been made in alleviating water erosion both theoretically and practically. This review serves as a foundation for advancing research and developing strategies to mitigate water erosion in sloped black soils and similar environments.