Freeze-thaw cycles (FTC) influence soil erodibility (K-r) by altering soil properties. In seasonally frozen regions, the coupling mechanisms between FTC and water erosion obscure the roles of FTC in determining soil erosion resistance. This study combined FTC simulation with water erosion tests to investigate the erosion response mechanisms and key drivers for loess with varying textures. The FTC significantly changed the mechanical and physicochemical characteristics of five loess types (P < 0.05), especially reducing shear strength, cohesion, and internal friction angle, with sandy loam exhibiting more severe deterioration than silt loam. Physicochemical indices showed weaker sensitivity to FTC versus mechanical properties, with coefficients of variation below 5 %. Wuzhong sandy loess retained the highest K-r post-FTC, exceeding that of the others by 1.04 similar to 2.25 times, highlighting the dominant role of texture (21.37 % contribution). Under different initial soil moisture contents (SMC), K-r increased initially and then stabilized with successive FTC, with a threshold effect of FTC on K-r at approximately 10 FTC. Under FTC, the K-r variation rate showed a concave trend with SMC, turning point at 12 % SMC, indicating that SMC regulates freeze-thaw damage. Critical shear stress exhibited an inverse response to FTC compared to K-r, displaying lower sensitivity. The established K-r prediction model achieved high accuracy (R-2 = 0.87, NSE = 0.86), though further validation is required beyond the design conditions. Future research should integrate laboratory and field experiments to expand model applicability. This study lays a theoretical foundation for research on soil erosion dynamics in freeze-thaw-affected areas.

The Sanjiangyuan region, known as the Chinese Water Tower, serves as a crucial ecological zone that is highly sensitive to climate change. In recent years, rising temperatures and increased precipitation have led to permafrost melt and frequent occurrences of thermokarst landslides, exacerbating soil erosion issues. Although studies have explored the impact of freeze-thaw action (FTA) on soil properties, research on this phenomenon within the unique geomorphological unit of thermokarst landslides, formed from degrading permafrost, remains sparse. This study, set against the backdrop of temperature-induced soil landslides, combines field investigations and controlled laboratory experiments on typical thermokarst landslide bodies within the permafrost region of Sanjiangyuan to systematically investigate the effects of FTA on the properties of soils within thermokarst landslides. Furthermore, this study employs the EPIC model to establish an empirical formula for the soil erodibility (SE) factor before and after freeze-thaw cycles (FTCs). The results indicate that: (1) FTCs significantly alter soil particle composition, reducing the content of clay particles in the surface soil while increasing the content of sand particles and the median particle size, thus compromising soil structure and enhancing erodibility. (2) FTA initially significantly increases soil organic matter content (OMC); however, as the number of FTCs increases, the magnitude of these changes diminishes. The initial moisture content of the soil significantly influences the effects of FTA, with more pronounced changes in particle composition and OMC in soils with higher moisture content. (3) With an increasing number of FTCs, the SE K-value first significantly increases and then tends to stabilize, showing significant differences across the cycles (1 to 15) (p < 0.05). This study reveals that FTCs, by altering the physicochemical properties of the soil, significantly increase SE, providing a scientific basis for soil erosion control and ecological environmental protection in the Sanjiangyuan area.

Freeze-thaw cycles (FTCs) influence soil erodibility through alterations in soil structure and mechanical properties. Despite existing studies, the quantitative relationship between soil erodibility and the number of freeze-thaw cycles (FTCs) at different initial soil water contents (ISWC) is still not fully understood. This study employed direct shear tests, soil disintegration tests, and pore size distribution (PSD) tests to quantify soil erodibility indices and soil structure characteristics for brown soil in Northeast China. Five FTCs (zero, one, five, ten, and fifteen) and five ISWC (10, 15, 20, 25, and 35%) were considered. The results revealed that as ISWC increased, soil cohesion generally declined, particularly with the rise in FTCs, making the difference in cohesion between high and low ISWC more pronounced. In contrast, the differences in internal friction angles between different ISWC gradually decreased as the FTCs increased. The soil disintegration rate was significantly affected by ISWC, showing an initial increase followed by a decrease as ISWC rose (p < 0.05). Notably, the range of 10-15% ISWC was the most easily disintegrated ISWC. FTCs could decrease the soil pore volume of lower ISWC and increase the soil pore volume of higher ISWC. 0.4 mu m radius pores were a critical threshold for pore changes in soil under FTCs and five FTCs might be the critical value for influencing macropores. FTCs could affect 0.1-4 mu m radius pores indirectly influencing the internal friction angle, and affect 4-25 mu m radius pores indirectly influencing the cohesion and disintegration rate. This paper introduces novel insights into the erosion characteristics and micro-mechanisms of brown soil under freeze-thaw conditions.

Human activities to improve the quality of life have accelerated the natural rate of soil erosion. In turn, these natural disasters have taken a great impact on humans. Human activities, particularly the conversion of vegetated land into agricultural land and built-up area, stand out as primary contributors to soil erosion. The present study investigated the risk of soil erosion in the Irga watershed located on the eastern fringe of the Chota Nagpur Plateau in Jharkhand, India, which is dominated by sandy loam and sandy clay loam soil with low soil organic carbon (SOC) content. The study used the Revised Universal Soil Loss Equation (RUSLE) and Geographical Information System (GIS) technique to determine the rate of soil erosion. The five parameters (rainfall-runoff erosivity (R) factor, soil erodibility (K) factor, slope length and steepness (LS) factor, cover-management (C) factor, and support practice (P) factor) of the RUSLE were applied to present a more accurate distribution characteristic of soil erosion in the Irga watershed. The result shows that the R factor is positively correlated with rainfall and follows the same distribution pattern as the rainfall. The K factor values in the northern part of the study area are relatively low, while they are relatively high in the southern part. The mean value of the LS factor is 2.74, which is low due to the flat terrain of the Irga watershed. There is a negative linear correlation between Normalized Difference Vegetation Index (NDVI) and the C factor, and the high values of the C factor are observed in places with low NDVI. The mean value of the P factor is 0.210, with a range from 0.000 to 1.000. After calculating all parameters, we obtained the average soil erosion rate of 1.43 t/(hm2 center dot a), with the highest rate reaching as high as 32.71 t/(hm2 center dot a). Therefore, the study area faces a low risk of soil erosion. However, preventative measures are essential to avoid future damage to productive and constructive activities caused by soil erosion. This study also identifies the spatial distribution of soil erosion rate, which will help policy-makers to implement targeted soil erosion control measures.

Purpose: The research examines the variation of soil erodibility index and physical characteristics due to iron placer mining activities and assesses the environmental impact of mining project by using MICOLD matrices.Methods: The research employed field samplings, laboratory analysis, and statistical analysis to study the variation of soil erodibility index and physical characteristics caused by iron placer mining activities. The study collected soil samples from the study area and conducted laboratory analysis to examine the physical and chemical properties of the soil. Statistical analysis was performed to analyze the data and identify the variation in soil erodibility index compared to natural conditions. Also, by modifying ICOLD matrices, environmental impact assessment of the project was evaluated.Results: The results of the paper indicate that there are significant differences between treated and untreated soils in terms of physical and chemical properties. The soil erodibility property (Ks) differs by -14.71% from natural conditions in top soils, although not significant statistically. In subsoil, Ks, clay, sand, Sp, Cu, Zn, Mn, Fe, and K differ significantly from untreated conditions (-43.38%, 35%, -15.07%, 5.28%, -192.50%, -242.55%, -101.86%, -333.34%, and -31.41%). The matrix of prediction and identification of the impacts related to the implementation of the mining project was created in two phases (construction phase and exploitation phase), the results of which show the total points in the construction phase and the exploitation phase have positive impacts and are equal to +71 and +171, respectively.Conclusions: The study examines the effects of iron placer mining operations on soil erosion characteristics and erodibility and suggests environmentally friendly solutions for minimizing the effects of mining on soil erosion. The research findings highlight the importance of considering physical characteristics of soils such as texture, infiltration, bulk density, and soil erodibility in evaluating the performance and efficiency of any project implemented on the Earth's surface. It emphasizes the need for designing well-operated devices and structures with little environmental damage to promote eco-innovation and green growth. The paper suggests that the environment is the most critical aspect of green surface mining, followed by efficiency and safety, and highlights the importance of microorganisms in mining environments and their role in constructing and producing primary succession for plant communities.