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• Dynamic change of soil erosion resistance were quantified. • Soil erosion resistance showed more spatial variation than temporal variation. • Mean weight diameter was the optimal index to describe the soil erodibility. • The critical shear stress was only affected by clay content. • Data strongly support an important effect of plant life-period on soil resistance. The water level fluctuations, rainstorms, and plants could lead to the variation in soil properties in the water-level fluctuation zone (WLFZ) and thus may influence the soil erosion resistance (soil erodibility, K r , and critical shear stress, τ c). However, variation in soil properties and its influence on the dynamic change of soil erosion resistance to overland flow in the WLFZ of the Three Gorges Reservoir (TGR) still unclear and need to be further quantified. Therefore, soil samples from different elevations were collected along a slope profile at different times in the WLFZ of the TGR, then the soil properties and plant biomass were measured and the soil detachment capacity (D c) were estimated by conducting a scouring experiment. Then the K r and τ c were obtained according to the linear relationship between D c and shear stress. The results indicated that most measured soil properties suffered low variability but organic matter content showed the moderate variability. K r varied from 0.10 to 0.17 s m−1 and τ c varied in the range of 1.56–2.24 Pa for all sampling points, and both showed spatial and temporal variations. K r decreased with increasing elevation until reaching a minimum value and then increased spatially, while it showed a decreasing trend or a decreasing trend followed by an increasing trend over time for different elevation segments temporally. τ c increased with increasing elevation spatially and increased or showed an increase followed by a decrease over time for different elevation segments temporally. K r was significantly influenced by clay, silt, and sand content, mean weight diameter and soil organic matter content, while τ c was only affected by clay content. These research results highlight the dynamic change of soil erosion resistance and are helpful for understanding the spatial and temporal variations in soil erosion resistance in the WLFZ of the TGR area. [ABSTRACT FROM AUTHOR]

Large areas of farmland have been established in China's Loess Plateau region by backfilling forest and grasslands in gullies with topsoil from hillslopes. High amounts of plant litter are incorporated into the topsoil during such processes; however, their effects on soil erosion resistance under natural conditions are not fully understood. Therefore, the present study investigated seasonal variation in soil erosion resistance to overland flow and the underlying factors in the gully-filled farmland. Two typical plant litter species were selected in this study, i.e., Artemisia sacrorum Ledeb. (ASL) and Bothriochloa ischaemum (L.) Keng. (BIL). Overland water flow was tested under six shear stress levels (5.66–22.11 Pa) in natural soil samples incorporated with plant litter and without plant litter to determine soil erosion resistance parameters (rill erodibility K r and critical shear stress τ c). The study was conducted over 524 days (through May 6, 2017, to October 11, 2018), covering two rainy seasons and one winter. Soil properties changed significantly over time, with physical crust thickness and cohesion increasing from 0 to 10.7 mm and 2.9–13.4 kPa, respectively. In contrast, the mass density of incorporated plant litter decreased from 0.7 to 0.2 kg m−2. Soil erosion resistance increased with time, which showed that K r decreased (from 0.516 to 0.021 s m−1) and τ c increased (from 0.49 to 7.98 Pa). Compared with the initial state of new farmland (K r = 0.507 s m−1, τ c = 0.48 Pa), K r decreased by 77–96% and τ c increased 8–14 times at the end of the study. Plant litter incorporation markedly enhanced soil erosion resistance in a time- and species-dependent manner. Compared with the bare soil without plant litter, the K r values of ASL and BIL treatments were 3–64% and 2–83% lower, and their τ c values were 0–81% and 0–55% higher, respectively. K r was significantly and positively correlated with cumulative precipitation, cumulative rainfall kinetic energy, soil cohesion, and physical soil crust thickness, while τ c was negatively correlated with the influencing factors. Further, both K r and τ c could be well predicted by physical soil crust thickness and cohesion (R2 = 0.79 and 0.87, p < 0.01, n = 27). According to the results, seasonal patterns of soil erosion resistance in the gully-filled farmland established under plant litter incorporation were mainly controlled by rainfall and physical soil crust structure. This study provides a reference resource for soil erosion prediction in farmland ecosystems on the Loess Plateau. • We monitored K r , τ c and potential influencing factors over 524 days. • The soil with litter incorporation has better soil erosion resistance. • Litter in the soil promotes the formation of physical soil crust by increasing SCT and Coh. • K r and τ c can be well predicted by SCT and Coh. [ABSTRACT FROM AUTHOR]

The rate of soil erosion from agricultural fields is driven by climate erosivity and by soil erodibility or resistance, commonly represented through the interrill (K i) and rill erodibility (K r), and critical shear stress (τ c) parameters. These parameters are affected by factors showing high variability in time and space, such as soil properties, land use, and management practices. Estimating the site-specific time-varying values for K i , K r , and τ c can require laborious field or laboratory experiments and detailed datasets. The objective of this research was to develop a non-linear regression model for estimating temporal adjustments for K i , K r , and τ c considering different types of crops and management practices. One thousand sampling sites were randomly selected across the Kaskaskia watershed in Illinois, and the needed parameters to develop the regression models were extracted from the two-year simulation results of the Water Erosion Prediction Project (WEPP) model on a daily basis. The predicted values of the regression models showed good agreements with the sample data, with the coefficient of determination (r 2) ranging from 0.62 to 0.98, capturing the spatio-temporal variations of the three variables under different crops and management practices. In addition, daily soil loss estimations using the predicted adjustments showed good agreements with the WEPP simulations, with r 2 ranged from 0.98 to 0.99, confirming their possible use in soil erosion models. This is especially useful as the regression models require only a few explanatory variables, which are available at high resolution across the United States. Therefore, the models will facilitate estimating spatio-temporal variations of interrill and rill erodibility, and critical shear stress and thus a new platform of large-scale soil erosion models can be developed using readily available environmental datasets. • Derived non-linear regression models for erodibility and critical shear stress. • The equations can capture the spatio-temporal variations in topsoil's resistance. • Explanatory variables are readily available at fine resolution. • The regression models can be applied to different crops and tillage practices. • The presented work can facilitate the estimations of soil erosion at larger scales. [ABSTRACT FROM AUTHOR]

In cold regions, frozen soil has a significant influence on runoff and water erosion. In the U.S. Inland Pacific Northwest, major erosion events typically occur during winter as frozen soil thaws and exhibits low cohesion. Previous applications of the WEPP (Water Erosion Prediction Project) model to a continuous bare tilled fallow (CBF) runoff plot at the Palouse Conservation Field Station (PCFS) in southeastern Washington State showed that WEPP reproduced the occurrence of the large erosion events, but the amount of sediment yield was either under- or overestimated. The inability of WEPP to reproduce the magnitude of field-observed erosion events at the PCFS suggests the need for an examination of the dynamic changes in soil erosion properties and for improving the representation of such dynamics. The objective of this study was to evaluate the seasonal changes of rill erosion parameters for two CBF runoff plots at the PCFS. Field-observed runoff and erosion events during 1984-1990 were used to estimate WEPP hydraulic and erosion parameters, including soil effective hydraulic conductivity, critical shear stress (τc), and rill erodibility (Kr). The parameters for each event were best-fitted using WEPP single-event simulations to reproduce the observed runoff and sediment yield on both plots. The results suggest that the adjustment factors for τc and Kr of frozen and thawing soils in the WEPP model could be modified to better describe the changes of these parameters in winter. [ABSTRACT FROM AUTHOR]

As forest management scenarios become more complex, the ability to more accurately predict erosion from those scenarios becomes more important. In this second part of a two-part study we report model parameters based on 66 simulated runoff experiments in two disturbed forests in the northwestern U.S. The 5 disturbance classes were natural, 10-month old and 2-week old low soil burn severity, high soil burn severity, and logging skid trails. In these environments the erosion rates were clearly detachment limited, and the rill erodibility parameters calculated from four hydraulic variables increased by orders of magnitude. The soil shear stress based erodibility parameter, K r, was 1.5 × 10−6 s m−1in the natural plots, 2.0 × 10−4 s m−1 in the high soil burn severity plots, and 1.7 × 10−3 s m−1 in the skid trail plots; K r values for the low soil burn severity plots had negative sign. The erodibility value for the skid trail plots fell within ranges reported for tilled agricultural fields and also for forest roads. The K r values decreased as erosion occurred in the plots and therefore should not be a constant parameter. The stream power produced the largest R2 value (0.41) when hydraulic predictors and the sediment flux were log-transformed, but none of the four hydraulic variables (soil shear stress, stream power, unit stream power, and unit length shear force) explained much of the variability in sediment flux rates across the five levels of disturbance when evaluated in the linear form of the erosion models under consideration. [ABSTRACT FROM AUTHOR]

The article reports on the result of the study of a field on rilling carried out in the experimental Sparacia area in South Italy. It stated that the measurement of the study were made on a plot six meter wide and 22 meter long subjected to natural rainfalls. It is revealed that the rill morphology was measured for five rainfall events while the rill profile was surveyed for three events. Moreover, it is observed that for three events detailed information on rill erosion and rill morphology allowed verification of the applicability of Water Erosion Prediction Project (WEPP) and estimation of the rill erodibility constant.

Abstract: Fire in sagebrush rangelands significantly alters canopy cover, ground cover, and soil properties which influence runoff and erosion processes. Runoff can be generated more quickly and in larger volume following fire resulting in increased risk of severe erosion and downstream flooding. The Water Erosion Prediction Project (WEPP) model was developed to predict erosion on cropland, forest, and rangeland. WEPP is a tool that has potential to model the effect of fire on hillslope hydrological processes and help managers address erosion and runoff risks following fire. Experimental results on a steep (35 to 50% slope) sagebrush site suggest that rill erosion is the dominant erosion process following fire and the WEPP parameterization equations related to the rill erosion process need improvements. Rill detachment estimates could be improved by modifying regression-estimated values of rill erodibility. Also, the interactions of rill width and surface roughness on soil shear stress estimates may also need to be modified. In this paper we report the effects of prescribed fire on runoff, soil erosion, and rill hydraulics and compare WEPP estimated erosion for several modeling options with measured erosion. [Copyright &y& Elsevier]

Abstract: There is a lack of quantitative information describing the physical processes causing soil erosion in the Andean Highlands, especially those related to interrill and rill erodibility factors. To assess how susceptible are soils to erosion in this region, field measurements of interrill (Ki) and rill (Kr) erodibility factors were evaluated. These values were compared against two equations used by the Water Erosion Prediction Project (WEPP), and also compared against the Universal Soil Loss Equation (USLE) erodibility factor. Ki observed in situ ranged from 1.9 to 56×105 kg s m−4 whereas Kr ranged from 0.3 to 14×10−3 s m−1. Sand, clay, silt, very fine sand and organic matter fractions were determined in order to apply WEPP and USLE procedures. Most of the evaluated soils had low erodibility values. However, the estimated USLE K values were in the low range of erodibility values. Stepwise multiple regression analyses were applied to ascertain the influence of the independent soil parameters on the Ki and Kr values. After this, we yield two empirical equations to estimate Ki and Kr under this Andean Highlands conditions. Ki was estimated using as predictors silt and very fine sand, while Kr used as predictors clay, very fine sand and organic matter content. Relationship among Ki, Kr and K are described for the Highland Andean soils. [Copyright &y& Elsevier]

The aim of this study was to determine the soil-erodibility parameters of the WEPP erosion model (Water Erosion Prediction Project) for an Andisol used to raise cattle in the Patzcuaro Lake watershed, Michoacan, Mexico. It was used a solenoid-operated rainfall simulator. Interrill detachment was measured in 0.5 m wide, 1.2 m long plots, and the detachment of flowing water was measured in 1 m wide, 3 m long plots; in both cases it was used a completely randomized design with four replications. Soil moisture affected runoff and interrill erosion, whereas the bulk density of the surface layer was lower in the cropland use than under the rangeland use. The interrill and rill erodibility parameters were 774.7x10³ kg sec m-4, and 0.5x10-4 sec m-1. These values in comparison with those reported in the literature permit to establish that the rangeland Andisol under study showed a moderated susceptibility to interrill erodibility and low detchment of flowing water. Soil compaction due to livestock trampling may have limited the erosivity of the concentrated flow and therefore the rill erosion. [ABSTRACT FROM AUTHOR]

• Rill detachment capacity (D c) was simulated in a flume varying sediment size, bed slope and flow rate. • Dc was significantly higher for sediments over 1 mm compared to other soil fractions. • Unit stream power is the best predictor of Dc using power equations. • Linear regression models between Dc and shear stress were very accurate. • Rill erodibility and critical shear stress are higher for sediments over 1 mm. Rill detachment is the most important erosive process in steep slopes and its comprehension and prediction accuracy is important to properly develop soil conservation practices in forest areas. This process is largely influenced by sediment size, soil slope and water flow characteristics, but the results of the studies that have explored these influences are contrasting. This study has simulated in an experimental flume the rill detachment capacity (D c) of soil with five particle sizes (0–0.25, 0.25–0.5, 0.5–1, 1–2, and 2–3 mm) at five water flow rates (0.26, 0.35, 0.45, 0.56, and 0.67 L m−1 s−1) and five bed slopes (3.5%, 9.1%, 19.2%, 29.1%, and 38.3%) on samples collected in a forestland of Northern Iran. D c was significantly higher (by 70%) for sediments size over 1 mm compared to the other soil fractions and increased primarily with soil slope and secondarily with water depth. A modelling approach has shown that the unit stream power is the best predictor of D c using power equations (NSE over 0.87). Linear regression models between D c and shear stress (τ) were very accurate (r2 over 0.80 with few exceptions) in predicting both rill erodibility and critical shear stress, when developed separately for each particle size class. Sediments with size higher than 1 mm had lower resistance to rill erosion compared to the finer fractions. Overall, the study helps to better understand particle detachment of the erosion process, on which particle size is a key parameter. The modelling activity proposes to land planners values of the rill erodibility and critical shear stress of forested areas for applications in process-based erosion models. [ABSTRACT FROM AUTHOR]

• The effects of plant roots on rill erosion were studied under contrasting textured soils. • Sand content significantly affected root biomass traits. • Erosion-reducing effects of root traits were less efficient in heavy-textured soils. • Plant with dense fibrous roots could be the optimal species mixtures to stable sandy slopes. The effects of plant roots on water erosion are likely to vary according to the range of root traits and soil textures. However, little is known about the erosion-reducing potential of roots under different soil textures due to the lack of sufficient texture variations which come from a comparable system. In this study, we systematically investigate how root functional traits respond to soil sand contents and their combined effects on rill erosion. Seeding of Cynodon dactylon (L.) Pers. were grown in a greenhouse under varied proportions of sand mass (ranging from 14% to 83%) by mixing silty clay soil (Ultisols derived from quaternary red clay) and engineering sand. After six months growing, the root-soil composites were subjected to concentrated flow in a hydraulic flume to obtain soil detachment capacity (D c), then roots were separated to measure their morphology and architecture traits. The results showed that sand content significantly affected root morphology traits (e.g., RD and RLD) (p < 0.01). In contrast, root architecture traits (e.g., root fractal dimension, topological index and radius frequency distribution function) showed no significant changes with soil texture (p > 0.05). Generally, root strongly promoted soil cohesion and they mitigated rill erodibility in a coordinated way. Rill erodibility was mostly determined by soil texture even in soils with dense roots, and the erosion-reducing effects of roots were less efficient in heavy-textured soils. Moreover, no significant correlations were found between critical flow shear stress (τ c) and root traits, and soil with a loam texture displayed the lowest τ c. Those relationships are likely to exist elsewhere, but its strength and direction could be changed according to the root trait variability and the varied root-soil feedbacks. The results of this study would be quite relevant for soil erosion modeling and imply the bare sandy soils are more urgent to be recovered during engineering constructions. Moreover, the inclusion of plant with dense fibrous roots could be the optimal species mixtures to stable sandy slopes. [ABSTRACT FROM AUTHOR]

• Rill detachment capacity (D c) was measured in hydromulched and bare plots after deforestation. • D c was 40% to 54% lower in the hydromulched soil compared to the untreated plot. • This reduction was due to the higher weight density and lower diameter of hydromulch roots. • Rill erodibility was much lower (−81%) in the hydromulched soil. • Critical shear stress and rill erodibility for deforested hillslopes (also after hydromulching) are given. Deforestation, which removes soil protection by plant leafs and roots, causes severe soil erosion, since the beneficial effects of plant cover and root actions on soil erodibility are lost. Hydromulching has been found to be a suitable technique for erosion control, but little research has been carried out to evaluate the effectiveness of hydromulch roots in controlling rill erosion in deforested areas due to overland flow. This study has evaluated rill detachment capacity (D c) and erodibility (K r , which is the slope of the equation regressing D c and critical shear stress) in hydromulched and bare plots (1.3-m long and 0.5-m wide) on soils sampled in deforested hillslopes of Northern Iran; the most important root parameters of the grass used for hydromulching were also measured, such as root density and diameter. D c has been measured in a laboratory flume under four bed slopes (10, 15, 20, and 25%) and five water discharges (0.26, 0.35, 0.45, 0.56, and 0.67 L m−1 s−1) with five replications per experiment. D c was lower (on average − 44%, with a minimum reduction of −40% at a slope of 25% and a maximum −50% at a slope of 15%) in the hydromulched soils compared to the untreated plot. D c was positively and negatively correlated, with diameter and density of hydromulch roots, respectively. Rill erodibility was noticeably lower (−81%) in the hydromulched soil compared to the bare plot. By regressing D c on shear stress, rill erodibility and critical shear stress for deforested hillslopes (treated with hydromulching or left bare) were given. These parameters are useful to hydrologists in applications of physically-based erosion models. [ABSTRACT FROM AUTHOR]

• An understanding the soil erosion under natural and planted forestlands is needed. • This study shows the effect of different vegetal species on rill detachment capacity. • Power regression equations to predict the detachment rate were developed. • The natural forest species control better the soil losses compared to the planted species. • Parrotia persica showed the lowest values of rill detachment capacity and Rill erodibility. Planted forests and management operation method can potentially alter the soil properties as a consequence of changes in the characteristics of tree and plant species. However, the effects of planted forest species with different root systems on the soil detachment capacity (D c) have not well been quantified. This study investigates the effects of plantation practice on the soil detachment capacity of soil with six vegetal species (Quercus castaneifolia, Alnus glutinosa, and Zelkova carpinifolia, as planted forest species) and Carpinus betulus , Parrotia persica , and Pinus taeda (as natural forest species) based on a comparison between natural and planted forests in forestland of the Saqalaksar Park (Northern Iran). To this aim, the soil detachment capacity on samples collected under trees of the studied species was measured in an experimental flume at five slopes (0.26, 0.35, 0.46, 0.57 and 0.69 m m−1) and flow rates (0.037, 0.086, 0.185, 0.285 and 0.376 L m−1 s−1). Moreover, simple prediction equations are suggested to evaluate the soil detachment capacity and rill erodibility (K r) for studied species. The soils of natural forestland showed the lower soil detachment capacity compared to soils of the planted forestland, due to the different influence of plant root systems. Moreover, the inappropriate management practices in planted forestland could have worsened the soil properties and thus increased the soil detachment rate. The unit stream power was better predictor of Dc compared to other hydraulic parameters in both natural and planted forestlands. The rill erodibility of soils was higher in planted forestland than in natural forestland. According to the results, the natural forestland is able to show higher resistance against soil erosion in comparison with the planted forestland. These findings indicate that for sustainable management of forest ecosystems, the maintenance of natural vegetal species can be an effective practice to reduce the soil erosion. [ABSTRACT FROM AUTHOR]

The beneficial effects of plant roots in decreasing soil detachment in forest ecosystems exposed to rill erosion are well known. However, these effects vary largely between different plant species. There has been lots of research into the relationship between root-soil systems and rill erodibility with a particular focus on grass species. Conversely, fewer studies are available for tree species, especially in forests of semi-arid or arid environments. Greater knowledge is therefore needed to identify the most effective tree species against rill erosion in these ecosystems, where water availability is the limiting factor for vegetation growth and afforestation is often the only solution to control erosion. To fill this gap, this study evaluates the rill detachment capacity of soils with four tree species (Parrotia persica, Carpinus betulus, Quercus castaneifolia, and Pinus taeda) in a semi-arid forest ecosystem in Northern Iran. These species are typical of these forests, but they also grow in other environmental contexts. The rill detachment was simulated in a laboratory flume at five slope gradients (1% to 5%) and five flow rates (0.22 to 0.69 L m−1 s−1) on soil samples with each of the tree species. The specific goal of the study was to evaluate which tree species with its specific root characteristics is most effective at reducing the rill detachment capacity. Moreover, simple prediction models are proposed to evaluate if it is possible to estimate the rill detachment capacity and rill erodibility (K r) from the unit stream power for the investigated tree species. The soils with Parrotia persica and Carpinus betulus showed the lowest and the highest rill detachment capacity, respectively. The greater root system biomass of Parrotia persica could have played a binding effect on the soil, thus improving its aggregate stability thanks to the action of plant's root system. Based on these results, Parrotia persica is able to provide a higher soil protection capacity against erosion compared to the other tree species. A logarithmic function was accurate in predicting the rill detachment capacity from the unit stream power at water flow rates over 0.0025 m s−1. By a regression between the rill detachment capacity and the shear stress of the soil, rill erodibility and critical shear stress of soils were estimated for the four tree species; the rill erodibility and critical shear stress are important input parameters for physically-based erosion models. Overall, the results of this study can support land planners in the choice of tree species most indicated for soil conservation as well as in the extensive application of erosion prediction models. [ABSTRACT FROM AUTHOR]

Plant root systems can greatly reduce soil loss, and their effects on soil erosion differ across species due to their varied root traits. The purpose of this study was to determine the effects of root morphology traits of herbaceous plants on the soil detachment process. Ten herbaceous plants (dominant species) in the Loess Plateau were selected, and 300 undisturbed soil samples (including living roots from the selected herbages) were scoured with flowing water to measure their soil detachment capacities under six levels of shear stress (4.98 to 16.37 Pa). Then, the root traits of each soil sample were measured, and the rill erodibility and critical shear stress were estimated based on the Water Erosion Prediction Project (WEPP) model. The results showed that root morphology traits varied greatly among the ten selected herbages. Accordingly, resulting variations in soil detachment capacity (0.030 to 3.297 kg m−2 s−1), rill erodibility (0.004 to 0.447 s m−1), and critical shear stress (4.73 to 1.13 Pa) were also observed. Plants with fibrous roots were more effective than those with tap roots in reducing soil detachment. Their mean soil detachment capacity and rill erodibility were 93.2% and 93.4% lower, respectively, and their mean critical shear stress was 1.15 times greater than that of the herbaceous plants with tap root systems. Of all the root traits, root surface area density (RSAD) was the primary root trait affecting the soil detachment, and it estimated the soil detachment capacity well (R2 = 0.91, normalized squared error (NSE) = 0.82). Additionally, an equation with few factors (soil aggregate and RSAD) was suggested to simulate the soil detachment capacity when the plant root parameters and soil properties were limited. Unlabelled Image • The effects of plant roots on D c was detected by overland flow under six shear stress. • Differences of root morphology traits among herbaceous species resulting great variations in D c , K r and τ c. • Plant roots decreased D c and enhance the soil resistance to flowing water. • RSAD would well present the effects of plant roots on soil detachment. [ABSTRACT FROM AUTHOR]

Permanent gullies are often initiated from rill erosion, followed by the formation of abrupt, deep and wide gullies when topsoil and subsoil are carried away by fast-flowing surface water. Few studies have been performed to evaluate soil detachment processes on hillslopes with permanent gullies, which may significantly affect the further development of gully erosion. Soil detachment was investigated by using natural undisturbed soil samples collected in different spatial locations (upper catchment, middle slope, lower slope, and scour channel) of hillslopes with permanent gullies. The relationships of soil detachment capacity with soil property, root system, and hydraulic parameters were quantified. Selected samples were tested in a hydraulic flume (3.8 m length × 0.2 m width) under five different shear stresses (3.67, 7.81, 10.50, 13.97 and 17.28 Pa). Soil detachment capacity was found to be significantly greater in the scour channel than in the other three hillslope positions. For the initial and stable gullies, the soil detachment capacity was notably reduced in the middle slope relative to the upper catchment and lower slope, while a different trend was observed in the active gully. The variability of soil detachment capacity at different spatial locations showed a negative correlation to bulk density, soil cohesion, clay, organic matter, and root density (P < 0.05), and a positive correlation to total porosity (P < 0.01). The rill erodibility (K r) showed a power function decrease with soil bulk density, organic matter, and root density (P < 0.01). Critical shear stress (τ c) had a significant and positive correlation with soil cohesion. Based on the WEPP model, detachment capacity of soil on hillslopes with permanent gullies could be achieved by using measurable parameters such of shear stress, bulk density, organic matter, root density, and soil cohesion. • Soil detachment capacity was investigated on hillslopes with permanent gullies. • The key factors influencing soil erosion resistance were analyzed. • Rill erodibility was influenced by bulk density, organic matter, and root density. • Critical shear stress had a positive correlation with soil cohesion. • An equation was developed for predicting soil detachment capacity. [ABSTRACT FROM AUTHOR]