Biochar amendment is widely recognized for its potential to enhance soil quality and control erosion over mid- to long-term periods. However, its short-term impact on rill erosion, particularly on soil detachment capacity (Dc) and rill erodibility (Kr), remains poorly understood across different soils. This study conducted flume experiments under varying hydrodynamic conditions (15° and 25° slope gradients; 12, 24, 36 L min−1 flow discharge rates) on five representative loess soils from the Loess Plateau, China, comparing untreated controls with soils amended with 3% corn straw biochar. Contrary to the common assumption of erosion mitigation, this study found that short-term biochar amendment universally increased Dc (by 19–264%) and generally raised Kr (by up to 218%) across all soil types, with the finest-textured clay loess being the most sensitive, whereas critical shear stress (τc) responses were soil-dependent. This unintended effect is likely associated with freshly incorporated biochar acting as discrete particles that disrupt native soil structure before stable organo-mineral associations develop. Soil organic carbon (SOC) was identified as the dominant factor controlling Dc and Kr. However, its accumulation was temporarily decoupled from erosion resistance, as its effects were expressed primarily through indirect pathways involving aggregate stability and porosity. Stream power (ω) was the optimal hydrodynamic predictor for Dc. Accordingly, we developed multivariate predictive models for Dc (including ω, SOC, mean weight diameter (MWD), capillary porosity (CP), and median particle diameter (D50); R2 = 0.669) and for Kr (SOC, MWD, specific surface area (SSA), and CP; R2 = 0.832). Our findings reveal a critical short-term erosion risk window, where biochar application may initially exacerbate rill erosion, providing a crucial temporal perspective for its management in erosion-prone landscapes.

The runoff coefficient (RC), defined as the proportion of precipitation converted into surface runoff during an individual rainfall event, exhibits pronounced spatial variability across different geomorphic regions owing to the combined influences of climate, topography, vegetation, and human activities. Using the Loess Plateau as a representative study area, we integrated multi-site observations and conducted a cross-regional comparative analysis to quantify the regional variability of event-based RC and identify its driving mechanisms. The results showed that the hilly–gully region (HG) showed the highest mean RC (0.14), followed by the rocky–mountainous zone (RM, 0.11), whereas the sandy zone (SD, 0.08), gully region (GR, 0.07), and valley plain (VP, 0.06) exhibited considerably lower values. RC showed a distinct land use gradient, with bare land > cropland > orchard > forest > shrub > grassland. Under Light, Moderate, and Heavy Rain, HG showed the highest RC, whereas RM exhibited the highest RC under Storm Rain. Structural equation modeling identified rainfall characteristics and land use as the dominant drivers of RC. Rainfall exerted positive total effects on RC in RM (0.41), GR (0.36), HG (0.31), and SD (0.29), but a slightly negative total effect in VP (−0.08). Land use exerted positive total effects on RC, particularly in RM, VP, and SD (0.42, 0.36, and 0.49, respectively), whereas vegetation exerted negative total effects (−0.37, −0.22, and −0.19, respectively). Soil moisture and terrain generally exerted weaker total effects on RC, with total effects varying markedly among regions. Overall, these results provide new insights into the regional variability and controlling mechanisms of RC across the Loess Plateau, supporting region-specific soil and water conservation.

Soil erosion, particularly inter-rill erosion, plays a critical role in the redistribution of soil organic carbon (SOC) and its associated fractions. However, the effects of rainfall kinetic energy (KE) on the dynamics of sediment and organic carbon loss remain poorly understood. This study investigates the influence of varying rainfall KE on sediment yield, runoff, particle size distribution (PSD), and SOC fraction loss during inter-rill erosion. To address these questions, micro-plots covered with iron mesh screens of varying apertures (1, 2.5, 5, 10, and 20 mm) were established to modulate rainfall KE, with a bare plot serving as the control. The objectives were to quantify the variations in sediment and SOC fractions in response to different rainfall KE levels, examine the relationships between rainfall KE and erosion parameters, and explore the mechanisms behind SOC fraction loss during erosion. The results indicated that increasing rainfall KE enhanced sediment and runoff yields, as well as sediment concentration, with a clear relationship between rainfall intensity, duration, and KE. PSD analysis revealed that the proportion of clay and silt initially decreased with increasing KE but later increased under higher KE, suggesting selective transport of fine particles as aggregates. Notably, SOC losses, including particulate organic carbon (POC) and mineral-associated organic carbon (MOC), decreased by 48.57% to 71.14% and 49.79% to 75.59%, respectively, compared to the control plot. MOC, the dominant fraction within SOC, was impacted by KE, both in terms of content and loss. Structural equation modeling (SEM) revealed that the loss of SOC fractions was primarily mediated by sediment yield, which was indirectly influenced by rainfall KE. Our findings highlight the complex interplay between rainfall KE, sediment dynamics, and SOC fraction transport during inter-rill erosion. This study contributes novel insights into the role of rainfall KE in shaping organic carbon distribution and provides a deeper understanding of erosion-induced carbon fluxes in the context of global carbon cycling.

Soil erosion in saline–sodic lands is a major driver of land degradation and sediment transport, necessitating innovative and sustainable soil conservation strategies. This study evaluated the effectiveness of waste-derived Morph-Genetic Porous Carbon (MGPC) as an emerging soil amendment for erosion control in saline–sodic soil from the Incheboron Region in Golestan Province, Iran. Biochar and MGPC were produced from problematic and underutilized waste biomasses, including various agricultural, industrial, and horticultural wastes, using three activation agents (H3PO4, KOH, and CO2). Based on specific surface area and porosity analyses, the three KOH-activated products from problematic straws, sawdust, and palm tree pruning were identified as the optimal samples. The selected MGPCs were mixed with soil at a 5 % by weight ratio and tested on small erosion plots under simulated rainfall on a 10 % slope. The results showed that, compared with the control, the sawdust-, straw-, and palm pruning-derived MGPC treatments significantly reduced soil loss by 88.52, 85.38, and 79.58 %, respectively (p < 0.001), and also significantly decreased sediment concentration (p < 0.001). These findings demonstrate that porous waste-derived carbon materials, particularly MGPC with favorable surface and pore characteristics, can substantially improve erosion resistance in saline–sodic soils. Therefore, MGPC represents a promising and sustainable option for soil and water conservation and for strengthening land management practices in saline and degraded environments.

The increasing generation of solid waste is recognized as one of the leading environmental and economic challenges. Optimal waste management, particularly in the agricultural and industrial sectors, necessitates innovative approaches for the efficient management of vital resources, including soil and water. One practical solution is the production of morpho-genetic porous carbon (MGPC) as a type of activated biochar, which has wide applications due to its porous structure, chemical and thermal stability, and high specific surface area. In this study, biochar was prepared with eight types of waste, including rice straw, vineyard prunings, palm prunings, sawdust, vinasse, poultry slaughterhouse waste, paper mill waste, and tissue paper production waste. Biochar production was carried out through a pyrolysis process under low-oxygen conditions and at a temperature of 400 °C. Biochar was converted into MGPC at a temperature of 800 °C using KOH and H3PO4 as activators at three different levels and CO2 at a single level. Then, using data obtained from the Brunauer–Emmet–Teller (BET) test, the game theory approach, and the Condorcet algorithm for evaluation, 64 MGPC samples were analyzed. BET analysis was performed to measure the specific surface area and pore structure. The data obtained from this analysis were extensively reported, encompassing approximately 40 criteria. However, only 12 criteria were selected, while about 28 criteria were excluded from the Condorcet algorithm due to the incompleteness of some of their data. This study investigated the process of biochar and MGPC production using agricultural and industrial wastes, with an emphasis on the role of game theory in promoting environmentally sound decision-making and optimizing MGPC applications. From 64 prepared samples, by examining their physical properties and environmental impacts, five priority samples, i.e., rice straw-KOH-level 2, sawdust-KOH-level 2, palm tree pruning waste-KOH-level 2, vineyard pruning waste-KOH-level 2, and tissue factory waste-KOH-level 2, with respective surface areas of 1071.47, 672.04, 860.54, 667.49, and 133.45 m2 g−1 and t-plot micropore volumes of 0.29, 0.24, 0.17, 0.19, and 0.02 cm3 g−1. were prioritized using the Condorcet algorithm. They were identified as suitable candidates for advanced applications in soil and water conservation due to their favorable porous structures and highly performed BET properties. The present study shows that innovative methods for producing MGPC can improve the performance and properties of porous materials for various applications.

Accurate mean flow velocity measurement is vital for rill-erosion and rill-flow hydraulic characteristics study. In dye tracing method, the velocity correction factor (alpha) is key to accurate mean flow velocity. In sediment-laden rill flow, sediment load and properties may affect alpha, but this effect is unclear. This study explored the variation mechanism of alpha with soil type and sediment load via indoor rill flume experiments under various combinations of five soil types, sediment loads, slope gradients, and flow discharges. Results showed alpha ranged from 0.40 to 0.95 under the experimental conditions; its mean values for transitional and turbulent flow were 0.61 and 0.67, respectively. Among soil properties, ultimate clay content was the core index that significantly influences alpha. The negative effect of sediment load and ultimate clay content on alpha is mainly achieved by inhibiting the turbulence intensity of flow, and their contributions rang from 0 % to 31.8 % and 8.6-83.1 % under different hydrodynamic conditions. As slope gradient and flow discharge increased, the influence of the sediment load on alpha diminished. The impact of the ultimate clay content on alpha was relatively weak under a low slope gradient combined with a high flow discharge. An estimation equation for alpha was constructed, which includes independent variables such as sediment load and ultimate clay content (R2 = 0.858). This equation showed a high accuracy in alpha prediction. These results provide a reliable basis for the rill erosion dynamic research and thus help improve the rill-erosion model precision.

Under climate change, soil erosion on the Loess Plateau has intensified, and the pronounced southeast-northwest gradients in climate, soils, and vegetation have produced marked regional differences in erosion processes. However, the mechanisms underlying these spatial variations remain insufficiently understood. Using seven years of observations from 32 monitoring stations, covering 672 natural rainfall events, hillslope runoff and soil loss were quantified across geomorphically distinct subregions. The result indicates that soil erosion is primarily controlled by rainfall, slope, and land use, while extreme rainfall and inadequate land management substantially amplify erosion risks. From light to torrential rain, runoff depth increased more than ninefold and soil loss more than thirty-fivefold, while bare land produced over seven times more soil loss than forestland. A southeast-northwest transition in dominant controls was identified: runoff generation becomes increasingly rainfalldriven, while the influence of land use and vegetation diminishes. Soil-loss pathways displayed distinct regional patterns-controlled primarily by the joint influence of runoff and land use in sandy regions, by topography-land use interactions in valley plains, and by runoff dynamics in hilly-gully and mountainous areas. Together, these results clarify the key processes underlying spatial variability in dryland erosion and provide a robust framework for assessing erosion risks and supporting adaptive land-management strategies under increasingly extreme climatic conditions.

Biochar impacts on soil respiration (Rs) remain uncertain, particularly in dryland regions where significant CO2 emissions result from rewetting. To examine these impacts, we conducted a three-year field experiment during the millet growing season to investigate the response patterns of Rs to biochar-induced changes in vertical soil temperature (Ts) and volumetric water content (VWC). Before Rs observation, the experimental site underwent three years of biochar amelioration (no planting) with five application rates of 1 %, 2.5 %, 4 %, 5.5 % and 7 % (BC1, BC2.5, BC4, BC5.5 and BC7, applied to the 0-20 cm soil layer). Rs was monitored within the 0-20 cm soil layer while Ts and VWC were measured simultaneously at soil depths of 5, 10 and 20 cm (Ts5, Ts10, Ts20, VWC5, VWC10 and VWC20). Moisture status within the Rs measurement range was partitioned by 0.093 m(3) m(-3) (the optimal VWC for Rs) for non-biochar amended soil (control). Overall, compared with the control, BC4, BC5.5 and BC7 significantly increased Rs (33.3-63.5 %) and experienced water stress earlier at a soil depth of 5 cm. In addition, high moisture levels caused significant differences in Rs among treatments. In terms of the relationship between Rs and Ts, the Gaussian-Ts model performed better than exponential-Ts in control only at a soil depth of 5 cm under low moisture conditions. For biochar treatments, Rs did not continue to rise with increasing Ts for BC1 and BC2.5 treatments under low moisture conditions and for BC5.5 and BC7 treatments under high moisture conditions across soil depths. With biochar application rate, Rs was dominantly shaped by VWC20 and Ts20 under low moisture conditions, while it was significantly influenced by Ts under high moisture conditions. These findings elucidate how Rs responds to biochar-induced changes in vertical Ts and VWC across moisture levels, providing valuable insights for comprehensively evaluating the environmental effects of biochar-amended soil in dryland areas.

During soil erosion, sediment load of rill flow changes dynamically and may affect its hydraulic characteristics. However, current research on hydraulics of sediment-laden rill flow primarily uses river sand/artificial homogeneous materials as sediment, which significantly differ from natural soil, leaving a research gap on how soil quantity impacts rill flow hydraulics. This study uses natural soil in an indoor rill flume simulation experiment to explore how sediment load influences hydraulic characteristics of rill flow, including flow velocity (V), Darcy-Weisbach friction coefficient (f), Reynolds number (Re), Froude number (Fr), and flow depth (h). Experiments were conducted under combinations of six different sediment loads, five flow discharges, and five slopes. The results indicated that V, f, Re, Fr were significantly influenced by sediment concentration. V and Fr show an upward trend as the sediment load increases, while f, Re, and h demonstrate a downward trend. The sediment load predominantly influences V, f, and Fr, accounting for contributions of 0.33, 0.49, and 0.39, respectively. The influence of slope gradient on V and Fr intensifies as the sediment load increases, while the impact of flow discharge on V, f, and Fr diminishes. As flow discharge increases, the effect of sediment load diminishes on V and Fr, and that of slope gradient strengthens. Two kinds of prediction equations were developed for estimating the hydraulic parameters of sediment-laden rill flow. The models demonstrate high R2 values (0.74 to 0.98), suggesting strong performance of the prediction equations. These findings lay a foundation for the better development of a physical process-based rill erosion model. Given the differences in the properties of natural soils, which may impact hydraulic characteristics, it is a limitation of this study that it only focuses on a single soil type, and thus future research should explore the effect of sediment properties on hydraulic characteristics.

Soil detachment and sediment transport are the two primary rill erosion processes. The sediment load in rill flow undergoes continuous variation due to the continuity and feedback of soil detachment and sediment transport processes, potentially impacting the soil detachment rate in the next stage. However, numerous studies focus on the soil detachment process by clear rill flow, and the few existing studies on soil detachment process by sediment-laden rill flow fail to consider the effect of soil properties. Therefore, this study was conducted to analyze the effect of soil properties and sediment load on the soil detachment rate by sediment-laden rill flow (Dr), decipher the variation in Dr, and establish a model equation to predict Dr, where soil properties and sediment load were introduced. An indoor rill flume simulation experiment was conducted under combinations of five soil types, five slopes, five flow discharges, and five sediment loads. The results revealed that the Dr of Shenmu sandy loess is the largest with a mean of 2.06 kg m- 2 s-1, followed by Dr of Ansai loess (1.57 kg m- 2 s-1), Yangling clay loess (1.37 kg m- 2 s-1), Dingbian sandy loess (1.19 kg m- 2 s-1), and Changwu loess (1.14 kg m- 2 s- 1). The effective clay content was the optimal soil property index correlation with Dr. Dr decreased with increasing sediment load and effective clay content. Variation partitioning revealed that the explanatory fraction of flow discharge was the highest (0.32), followed by the sediment load (0.21), slope (0.19), and effective clay content (0.14). There are interactions among the influencing factors in process of soil detachment. The sediment load level and effective clay content could inhibit the influence of flow discharge on the Dr. The higher the slope, flow discharge, and sediment load level, the greater the influence of the effective clay content on the Dr. Dr by sediment-laden rill flow can be modeled using a quaternary power function of the slope gradient, flow discharge, sediment load, and effective clay content (R2 = 0.863). Introducing the sediment load and effective clay content as factors in the model equation of Dr can improve the simulation precision. These findings aid in advancing the development of a physical process-based rill erosion model.

Revealing the spatial distribution mechanism of the coupling effect between soil water and salt is essential for managing saline-alkali farmland. This study utilized the multifractal method to analyze soil water and salt under varying water content levels in arid saline-alkali farmland. Soil samples were collected on the second (S1), fifth (S2), eighth (S3), eleventh (S4), and fourteenth (S5) days after a rainfall event. The findings showed that a significant decrease in soil water content, contrasting with an increase in soil salt content throughout the soil layers post-rainfall. As water content decreased, the spatial variability of soil water initially increased from S1-3 and then decreased, while the spatial variability of soil salt decreased. The spatial distribution between soil water and salt exhibited a high correlation at S3-4 (with relative water content of soil ranging from 0.52 to 0.75) due to their coupling effect. However, soil salt was unevenly leached by rainfall at high water content levels (S1-2) and precipitated at low water content levels (S5), resulting in low spatial variability correlations between soil water and salt. This study elucidated the coupling process of soil water and salt, identifying their spatiotemporal distribution mechanism in dryland agricultural areas.

Investigating the spatial distribution characteristics of the interaction between soil salinity and moisture is crucial in revealing moisture–salinity interaction in semi-arid farmland. The sampling of soil was performed on the second (S1), fifth (S2), eighth (S3), eleventh (S4), and fourteenth (S5) days after the erosive rainfall. The multifractal method was used to analyze spatial distribution parameters of soil moisture and salinity under the different stages. The findings showed that the soil moisture content decreased from 22.44% to 12.73%, while the salinity increased from 0.71 to 1.18 g kg–1 after the rainfall. As the amount of moisture in the soil decreased, the variability in the distribution of moisture initially increased from S1 to S3 and then decreased, while the salinity content also decreased. The spatial distribution of soil moisture and salinity content showed a strong correlation at S3 to S4 (with the relative water content of soil ranging from 0.52 to 0.75), indicating a significant coupling effect in these stages. However, the distribution of soil salinity was not uniform under high moisture content conditions (S1 to S2), as it was leached unevenly by rainfall, and under low moisture content conditions (S5), it precipitated, resulting in a low correlation between the spatial distribution of soil moisture and salinity content. This research has provided insight into the coupling dynamics of soil moisture and salinity content, revealing the mechanisms governing their spatial distribution in dryland agricultural regions.

Understanding the interactions between influencing factors on sheet erosion is crucial for model development and mechanism elucidation. Simulation rainfall tests using a full-factorial design were conducted in 0.4 m wide flumes with five slope lengths (0.4, 0.8, 1.2, 1.6, and 2 m), five slope gradients (17.63, 26.79, 36.40, 46.63 and 57.74 %) and five rainfall intensities (48.0, 62.4, 102.0, 148.5, and 170.1 mm & sdot;h-1) to quantity interactions between these factors on sheet erosion and runoff rate by using Multiple Linear Regression. The results revealed that adding all two-way interaction terms into the equation, such as Rainfall intensity * Slope length (IL), Slope gradient * Rainfall intensity (SI) and Slope gradient * Slope length (SL), significantly improved the interpretation of erosion and runoff rate. Under various slope gradients, the interaction item IL had a negative impact on erosion rate with an average slope of-0.86, but a positive impact on runoff rate with an average slope of 4.33, which improved the interpretation of regression equations for erosion and runoff rate by 0.86 %-1.83 % and 0.21 %-0.47 %. SI exhibited a positive effect on both erosion and runoff rate with an average slope of 4.36 and 8.44, and enhanced the interpretation for erosion and runoff rate by 0.70 %-3.54 % and 0.02 %-0.32 % under various slope lengths. SL had a negative effect on both erosion and runoff rate with an average slope of-3.55 and -6.93, and increased the interpretation of erosion and runoff rate by 1.15 %-6.84 % and 0.10 %-2.26 % under various rainfall intensities. The roles of I and S on erosion and runoff are both mutually promoting, of S and L are both mutually hindering, and of I and L on erosion are mutually hindering but on runoff are mutually promoting. Additionally, the interactions between I, L and S were even higher than that of a single influencing factor in some cases. Our findings highlight the need to consider the two-way interactions between influencing factors when predicting soil loss and provide methodological guidance for quantifying the interactions on soil erosion.

To identify the key parameters and develop accurate experimental models of detachment and transport, splash detachment and transport of loess soil were investigated in relation to the rainfall characteristics and slope. The experiment was conducted under 25 combinations of five rainfall intensities (60, 84, 108, 132 and 156 mm h−1) and five slope gradients (0°, 5°, 10°, 15° and 20°), using a custom splash pan. Raindrop characteristics (diameter, velocity and kinetics) and splash mass were measured in downslope and upslope. The results indicated that rainfall intensity and slope contributed 94.77% and 0.46%, respectively, to the detachment rate, and 24.39% and 67.82%, respectively, to the transport rate. From a holistic viewpoint, the positive effect of slope became more visible on the detachment rate when the rainfall intensity exceeded 108 mm h−1, and on the transport rate when the slope exceeded 15°. Based on the rainfall simulator in this study, the rainfall kinetic energy (KE, J), raindrop median particle size (D50, mm) and raindrop terminal velocity (V, m s−1) all increased with increasing rainfall intensity (I) within the 60~108 mm h−1 range but decreased with increasing rainfall intensity within the 132~156 mm h−1 range. The rainfall intensity and raindrop characteristics (D50/V/KE) are the key parameters of splash detachment (Dr, g·m−2 min−1), and three detachment models were developed: (1) Dr = 0.1153 I1.09D500.79 (R2 = 0.99, NSE = 0.98, p < 0.01); (2) Dr = 0.0162 I1.11V1.22 (R2 = 0.99, NSE = 0.99, p < 0.01); and (3) Dr = 0.0813 I1.10KE0.18 (R2 = 0.99, NSE = 0.99, p < 0.01). The rainfall intensity and slope are the key parameters for splash transport (Tr, g·m−2 min−1), and the developed transport models could be expressed as: (1) Tr = 0.00657 I1.343S0.116 (R2 = 0.914, NSE = 0.874, p < 0.01) (slopes of 0°, 5° and 10°) and (2) Tr = 0.00218 I1.165S1.033 (R2 = 0.986, NSE = 0.986, p < 0.01) (slopes of 15° and 20°). The results of this study could enhance the understanding of soil splash detachment and transport on loess slopes.

Large-scale vegetation restoration can reduce local watershed water yield, limit vegetation establishment and subsequent growth, and influence regional ecosystem functions. Clipping management by reducing aboveground parts of grassland was gradually recommended and adopted in Grain-for-Green project management to offset these additional issues. Thus, scientific evaluation of the effectiveness of clipping management on infiltration and runoff processes is necessary for maintaining the stability of the surface water system and the sustainability of vegetation restoration in semi-arid regions. A field simulated rainfall experiment was conducted with four managed clipping grasslands (mainly bunge needlegrass and Stipa grandis), including no clipping, light clipping, heavy clipping, and complete clipping under three slope gradients (10, 20, and 30°) and three rainfall intensities (60, 90, and 120 mm/h) to explore the mechanism of runoff and infiltration responses to clipping using structural equation modeling and variation partitioning based on an SCS-CN model. The results showed the runoff coefficient of the light clipping, heavy clipping, and complete clipping plots were 1.33, 2.22, and 4.22 times that of the no clipping plot. The light clipping, heavy clipping, and complete clipping plots decreased the infiltration coefficients by 0%, 5%, and 26% relative to the no clipping plot. Rainfall intensity dominated runoff and infiltration amounts, and clipping intensity's total effect was stronger than slope gradient. Clipping intensity and slope gradient were more influential on runoff with increasing rainfall intensity. The mutual inhibition effect was between clipping intensity and slope gradient on runoff. In order to maintain the sustainability of restoration, a 25–50% vegetation coverage after clipping maximizes the benefits of increasing runoff and maintaining enough soil water supply that prevents possible soil drought. We propose that future vegetation restoration policies should evaluate the appropriate clipping intensity; meanwhile, local physiographic and climate conditions should be considered. These findings may offer guidance for the development of measures for runoff regulation and ecosystem functions of the watershed during vegetation restoration on the northern Loess Plateau.

Clipping management, which alters vegetation conditions by removing aboveground vegetation while preserving the underground root system, directly impacts hydrological processes and flow dynamics, ultimately affecting soil erosion processes. This study conducted field experiments (2 x 6 m) encompassing four clipping intensities (with vegetation coverage of 70%, 50%, 25%, and 0%), three rainfall intensities (60, 90, and 120 mm center dot h(-1)), and three slope gradients (10(degrees), 20(degrees), and 30(degrees)). The results showed that clipping treatments significantly reduced the Darcy-Weisbach resistance coefficient (f). Elevated levels of clipping intensity, rainfall intensity, and slope gradient led to increased flow velocity (v), Reynolds number (Re), and stream power (omega). The shear stress (tau) exhibited an upward trend with rising slope and rainfall intensity, with no significant difference in the effect of clipping intensity. Variation partitioning analysis demonstrated that the influence of steep slopes amplified the effects of rainfall intensity while diminishing the impact of clipping intensity on v values. Critically, the Bayesian network model suggested that, in comparison to the influence of raindrop splashing, soil detachment and transportation by runoff were the predominant driving mechanisms for erosion on slopes with clipped vegetation. Rainfall intensity and clipping intensity were found to raise the runoff depth and enhance the v value, which ultimately influenced soil erosion. Overall, these results contribute to an improved comprehension of the hydraulic dynamics of soil erosion on slopes with clipped vegetation and provide invaluable perspectives for developing effective clipping management strategies to ensure sustainable land utilization and judicious water resource governance.

通过野外微小区原位观测试验,基于降雨过程中降雨的集中时段对 2017-2021 年 34 次侵蚀性降雨雨型进行划分,系统分析雨型变化对黄土坡面细沟间侵蚀的影响及坡度效应.结果表明:研究区以前期型降雨为主,占总场次的 52%,中期型和后期型降雨各占 24%.中期型降雨对总产流量的贡献(25.56%±3.83%)显著低于前期型(36.70%±2.07%)和后期型(37.74%±4.01%)(p<0.05).不同雨型场均径流量依次为后期型>中期型>前期型,后期型和中期型降雨显著高于前期型.而降雨的场均产沙量则表现为后期型>前期型>中期型,且后期型降雨显著高于中期型(p<0.05).雨型对细沟间侵蚀影响的坡度效应变化不明显,但随着坡度增大,后期型降雨的场均径流量和产沙量均大于前期型和中期型,说明后期型降雨的产流产沙对坡度变化相对较为敏感.次降雨径流量、坡度和降雨参数组合与次降雨产沙非线性拟合中,方程决定系数后期型(0.939～0.942)>中期型(0.776～0.845)>前期型(0.220～0.537),说明区分雨型模拟可提高模拟精度.

Effective soil particle size composition can more realistically reflect the particle size sorting process of erosion. To reveal the individual contributions of rainfall intensity and slope to splash erosion, and to distinguish the enrichment ratio of each size and the critical size in splash, loessial soil collected on the Loess Plateau in May 2019 was tested under different rainfall intensities (60, 84, 108, 132, 156 mm h−1) and slopes (0°, 5°, 10°, 15°, 20°). The results demonstrated that 99

Clipping management by reducing the above-ground parts of grassland has been gradually introduced to offset some of the additional issues caused by large-scale vegetation restoration, such as the formation of a dry soil layer, approaching the limits of watershed water resources, and reducing the sustainability of vegetation. Therefore, there is a scientific and practical need to evaluate the effectiveness of clipping management on runoff and erosion processes to ensure a balance between erosion control, surface water supply, and vegetation sus-tainability. In this study, simulated rainfall experiments with four levels of clipping intensities (no clipping, light clipping, heavy clipping, and clear clipping) were conducted to explore the mechanism of runoff and soil loss response under three rainfall intensities (i.e., 60, 90, and 120 mm center dot h-1) and three slope gradients (i.e., 18, 36, and 58 %) using structural equation modeling and variation partitioning. The results showed that the runoff depth increased by 42 %, 119 %, and 299 %, respectively, and the soil loss increased by 76 %, 80 %, and 470 %, respectively, in the light, heavy, and clear clipping treatments compared with the no clipping treatment, indi-cating that the increase in the percentage of runoff production and soil loss was not synchronized. According to the optimizing results of response surface method, the recommended vegetation cover after clipping was 23 % -48 %, and the slope gradient of clipped vegetation should not exceed 36 %, which increased surface runoff while limiting soil erosion within an acceptable range. Runoff production and soil loss were primarily determined by rainfall intensity, followed by clipping intensity and slope gradient. Increasing rainfall intensity and slope gradient increased the effect of clipping on soil loss. Therefore, local rainfall and topography need to be considered in the application of clipping management. This study provides valuable insights into the use of clipping treatment as a sustainable management strategy for mitigating soil erosion and conserving surface water resources, and has important implications for developing restoration plans to promote sustainability in semi-arid ecosystems.

Biocrusts play a critical role in prevention of erosion, but little is known on the relationship between biocrust cover and raindrop detachment capacity at the slope scale. Evaluating the raindrop detachment capacity on biocrusted slope is essential for better knowledge of the rainfall-induced erosion of biocrusted slope. Thus, laboratory simulated rainfall experiments were conducted on plots (140 x 120 cm) representing moss-dominated biocrusted slopes to measure the amounts of raindrop detachment under a complete combination of different biocrust cover (0%, 20%, 40%, 50%, 60%, and 80%) and rainfall intensities (42, 60, 90, 120, and 150 mm h-1) at 26.79% slope gradient with two replications. The results showed that the biocrust cover, rainfall intensity, and their interaction all significantly affected the raindrop detachment modulus (RDm). The RDm in biocrust plot was significantly lower than in bare soil plot under rain events with the same rainfall intensities. The lower biocrust cover or the larger rainfall intensities led to higher RDm. Reduction benefit of raindrop detachment modulus (RB-RDm) were greater than its corresponding biocrust cover values. When the biocrust cover increased from 20% to 40%, the increase range and growth trend of RDm decreased with increasing rainfall intensity. Our results indicated that the development of biocrusts on slope is an effective way of reducing raindrop detachment by protecting soil in their covered area and increasing flow depth. When moss-dominated biocrust cover reached 40%, the raindrop detachment capacity effectively weakened even under rain events with large rainfall in-tensities. These findings may conducive to offer a scientific guidance for soil erosion control in the Loess Plateau and in other arid and semiarid regions.