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Solifluction processes in the Arctic are highly complex, introducing uncertainties in estimating current and future soil carbon storage and fluxes, and assessment of hillslope and infrastructure stability. This study aims to enhance our understanding of triggers and drivers of soil movement of permafrost-affected hillslopes in the Arctic. To achieve this, we established an extensive soil deformation and temperature sensor network, covering 48 locations across multiple hillslopes within a 1 km2 watershed on the Seward Peninsula, AK. We report depth-resolved measurements down to 1.8 m depth for May to September 2022, a period conducive to soil movement due to deepening thaw layers and frequent rain events. Over this period, surface movements of up to 334 mm were recorded. In general, these movements occur close to the thawing front, and are initiated as thawing reaches depths of 0.4-0.75 m. The largest movements were observed at the top of the south-east facing slope, where soil temperatures are cold (mean annual soil temperatures averaging −1.13 °C) and slopes are steeper than 15°. Our analysis highlights three primary factors influencing movements: slope angle, soil thermal conditions, and thaw depth. The latter two significantly impact the generation of pore water pressures at the thaw-freeze interface. Specifically, soil thermal conditions govern the liquid water content, while thaw depth influences both the height of the water column and, consequently, the pressure at the thawing front. These factors affect soil properties, such as cohesion and internal friction angle, which are crucial determinants of slope stability. This underscores the significance of a precise understanding of subsurface thermal conditions, including spatial and temporal variability in soil temperature and thaw depth, when assessing and predicting slope instabilities. Based on our observations, we developed a factor of safety proxy that consistently falls below the triggering threshold for all probes exhibiting displacements exceeding 50 mm. This study offers novel insights into patterns and triggers of hillslope movements in the Arctic and provides a venue to evaluate their impact on soil redistribution.

To comprehensively consider the influence of boundary conditions, non‐Darcy flow, load forms, and soil stratification on soil consolidation, a one‐dimensional soil consolidation equation is established. By subdividing the soil layer and employing time discretization, the nonlinear consolidation equation is linearized, resulting in an analytical solution for layered soil foundation at any given time. Subsequently, an iterative approach for time solution is employed to obtain a semi‐analytical solution. The correctness of the solution is verified by comparison with solutions based on Darcy's flow and the semi‐analytical method under traditional drainage boundary conditions. Subsequently, the influence of interface parameters, loading conditions, flow index, and other factors on consolidation characteristics is analyzed. The results indicate that higher interface parameter values for continuous drainage boundaries correspond to faster average consolidation rates for stratified soil foundations, while these parameters have little effect on the time required for complete consolidation of the soil layers. Improved boundary drainage performance amplifies the influence of exponential flow on pore water pressure and average consolidation degree. Conversely, poor boundary drainage performance diminishes the impact of exponential flow on soil consolidation, rendering it negligible. Moreover, faster loading rates accentuate the influence of the flow index on the average consolidation degree defined by pore pressure. [ABSTRACT FROM AUTHOR]

This study investigated the impact of thinning and felled logs (random- and contour-felled logs) on overland flow, soil erosion, and litter erosion in a Japanese cypress forest plantation (2400 tree ha−1) with low ground cover, from 2018 to 2023 in central Japan. Monthly measurements of overland flow and soil and litter erosion were carried out using small-sized traps across three plots (two treatments and one control). In early 2020, a 40% thinning (tree ha−1) was conducted in the two treatment plots. Overland flow increased in the plot with random-felled logs during the first year post-thinning (from 139.1 to 422.0 L m−1), while it remained stable in the plot with contour-felled logs (from 341.8 to 337.1 L m−1). A paired-plot analysis showed no change in overland flow in the contour-felled logs plot compared to the control plot from the pre- to post-thinning periods (pre-thinning Y = 0.41X − 0.69, post-thinning Y = 0.5X + 5.46, ANCOVA: p > 0.05). However, exposure to direct rainfall on uncovered ground areas post-thinning led to increased soil and litter erosion in both treatment plots. These findings suggest that thinning combined with contour-felled logs effectively stabilizes overland flow. Therefore, thinning with contour-felled logs can be considered a viable method for mitigating overland flow in monoculture plantations with low ground cover. [ABSTRACT FROM AUTHOR]

This study aims to address the harmful effects of excessive nitrogen fertilizer by investigating the mobility retardance effect of zeolite on nitrate movement in loam soil columns. Disturbed and undisturbed soil columns, treated with zeolite, as well as control soil columns, were analysed over a span of three years. Breakthrough curves generated from the experiments were evaluated using the HYDRUS1D code with mobile–immobile water (MIM) and dual-permeability (DP) models. Our findings highlight that zeolite application significantly reduced nitrate mobility, with recovery rates decreasing by 8% in disturbed and 11% in undisturbed columns. The DP model, which accurately reflects real soil water flow conditions, outperformed the MIM model in predictive accuracy. This research offers a novel long-term perspective on the benefits of zeolite in enhancing soil properties and mitigating nitrate leaching, recommending the DP model for superior prediction of contaminant transport in structured soils within the vadose zone. [ABSTRACT FROM AUTHOR]

ABSTRACT Cohesive material columns have been extensively used in foundation improvement projects to enhance the bearing capacity of composite foundations and mitigate post‐construction settlement. However, the low permeability of cohesive material columns restricts the dissipation of pore water primarily through the top surface of the foundation, potentially resulting in longer drainage paths compared to foundations treated with granular material columns or vertical drains. Moreover, the impact of non‐Darcian flow within soils on consolidation behavior becomes increasingly pronounced as the drainage path increases. Consequently, a novel analytical model for the consolidation of impervious column‐assisted foundations is established, which can incorporate the seepage model accounting for the initial hydraulic gradient. The accuracy and reasonableness of the obtained solution are then validated by conducting a comparative analysis with existing models and through a detailed case study. Furthermore, a parametric analysis is conducted to delve into the influence of several crucial factors on the consolidation performance. The findings demonstrate that non‐Darcian flow has a greater influence on composite foundations compared to natural foundations. Additionally, the threshold value of the well‐diameter ratio decreases with the increase in the initial hydraulic gradient. Finally, the final seepage front remains at a shallower position when the column–soil modulus ratio becomes larger, and the influence of non‐Darcian flow on the consolidation rate becomes more pronounced. [ABSTRACT FROM AUTHOR]

Since aquifers deform under applied stresses, it is important to understand the interaction between fluid flow and soil deformation, as the deformation of the solid matrix affects the storage of water in the void space and may reach an extent that causes land subsidence under certain conditions. Geological heterogeneity has a major influence on groundwater movement and can therefore affect the amount of compaction. The aim of this work is, therefore, to perform a stochastic analysis of the influence of the variability of hydraulic conductivity fields on the interaction between excess fluid flow and soil deformation in heterogeneous, deformable porous media. The stress equilibrium equation and the storage equation together form a pair of coupled constitutive equations to describe the interaction of deformation (volume strain) and excess pore fluid pressure head. Using the Fourier–Stieltjes representation approach and a perturbation approximation, the coupled equations are solved analytically in the Fourier space domain for the case of unidirectional excess mean flow. Based on these solutions and the representation theorem, results are obtained for the variances of excess pore fluid pressure head and volume strain. They serve as an index of variability quantification for the evaluation of the variability of the log conductivity field and the compressibility coefficient of the soil on the variability of pressure head and volume strain fields. An illustration of the application of the proposed stochastic theory to predict the excess pore pressure and volume strain under uncertainty is also given. [ABSTRACT FROM AUTHOR]

Xerophytic vegetation re-regulates and allocates water resources through canopy interception, root water uptake and transpiration, and changes the water budget among precipitation, runoff, interception and infiltration, thus having a significant impact on the processes of the hydrological cycle. In this study, we investigated the effect of xerophytic shrub-Salix on soil water redistribution and water budget through an in situ monitoring experiment combined with two-dimensional vegetation water consumption modeling. The results showed that, due to the interception effect of root water uptake, it was difficult for precipitation infiltration to recharge deep soil water and groundwater. The measured data of soil moisture content, hydraulic head and precipitation were used to verify and calibrate the performance of the soil water flow model in the vadose zone by HYDRUS-2D. The effect of roots system on soil water was simulated, and the appropriate spacing of Salix replanting was estimated. Combined with the relationship between the transverse roots system and the crown width obtained by the investigation, it was determined that the spacing between the Salix should be greater than five times the crown width, so that the balance between the water consumption of Salix and the water supply of deep soil by precipitation could be considered. The results of this study are important for estimating groundwater recharge in arid areas and provide practical vegetation replanting options for similar regions. [ABSTRACT FROM AUTHOR]

Carbon and nitrogen leaching and seepage with subsurface flow is one of the main paths of soil carbon and nitrogen loss. However, as great challenges lie in direct observation, soil carbon and nitrogen leaching related research is relatively lagging behind. Especially due to the complexity of the soil subsurface flow, some problems have not been fully elucidated. In this paper, the characteristics and observation methodologies of soil carbon and nitrogen leaching under the influence of soil, environment and subsurface flow were first summarized, and numerous complicated factors demonstrated to affect carbon and nitrogen leaching, where the influence of rainfall and soil properties were pre-dominant. Field measurement could reflect the natural process of leaching, the indoor experiment could effectively quantify the influential factors on leaching, and the mathematical model could help understand the physical mechanism of carbon and nitrogen leaching by simulating water flow and matter transport in porous media. Future research could combine these methods to achieve a better research effect. The aim of this paper was to provide a certain understanding of the role of carbon and nitrogen in the process of matter cycling and nutrient transfer, and to provide a scientific basis for better regulation of the dynamics of carbon and nitrogen mineralisation, sequestration, leaching and plant uptake in future ecosystems. [ABSTRACT FROM AUTHOR]

Aiming at the problems of low soil cover and serious wear and tear of transmission parts in the soil lifting device of potato planters, this paper carries out innovative optimization design of its key parts based on TRIZ theory. The discrete element model of the soil model and the multi-body dynamic model of the soil lifting device are established, the upper scraping and lower scraping soil lifting devices are simulated respectively through the method of DEM-MBD coupling, and the working mechanism of the soil lifting device is further explored. The simulation results show that the lower scraping type lifting device has a large conveying capacity and a stable flow rate at the soil outlet. The results of the soil tank performance comparison test show that: the improved soil lifting device has a simple structure, large conveying capacity, stable flow rate, and fast flow speed and is not easily congested. It meets the standard requirements of dryland potato seedling strip mulching planting technology on mulching parameters and is of great significance for improving dryland food production on the Loess Plateau. [ABSTRACT FROM AUTHOR]

This study presents a novel approach for modeling unsaturated flow using deep neural networks (DNNs) integrated with spacetime radial basis functions (RBFs). Traditional methods for simulating unsaturated flow often face challenges in computational efficiency and accuracy, particularly when dealing with nonlinear soil properties and complex boundary conditions. Our proposed model emphasizes the capabilities of DNNs in identifying complex patterns and the accuracy of spacetime RBFs in modeling spatiotemporal data. The training data comprise the initial data, boundary data, and radial distances used to construct the spacetime RBFs. The innovation of this approach is that it introduces spacetime RBFs, eliminating the need to discretize the governing equation of unsaturated flow and directly providing the solution of unsaturated flow across the entire time and space domain. Various error evaluation metrics are thoroughly assessed to validate the proposed method. This study examines a case where, despite incomplete initial and boundary data and noise contamination in the available boundary data, the solution of unsaturated flow can still be accurately determined. The model achieves RMSE, MAE, and MRE values of 10−4, 10−3, and 10−4, respectively, demonstrating that the proposed method is robust for solving unsaturated flow in soils, providing insights beyond those obtainable with traditional methods. [ABSTRACT FROM AUTHOR]

The boundary at anode was generally assumed to be impermeable in previous work. However, the horizontal electro-kinetic geosynthetics are typically arranged at intervals, forming a permeable anode that allows pore water in original soil to flow through the gaps, which inevitably affects the consolidation process of electroosmotic layer. A one-dimensional analytical model for the coupled consolidation of original soil and electroosmotic layer is established to study this effect. The rationality of the one-dimensional model is justified by comparing the results of a two-dimensional model. To obtain the analytical solution, new dummy variables are proposed to homogenize the continuity conditions. The analytical solution is derived using the separate variable method and verified by existing analytical solutions and numerical results. Parametric analysis reveals that the consolidation time would be more significantly delayed in the thicker original soil. Both the permeability and compressibility of original soil influence the delayed effect on the consolidation of electroosmotic layer but the latter is more significant. For the equivalent thicknesses of original and electroosmotic layers, the time to reach 90% average degree of consolidation increases up to more than 6 times for the compression coefficient ratio of original and electroosmotic layers being equal to two. [ABSTRACT FROM AUTHOR]

This investigation explores the erosion dynamics in sandy soils triggered by underground pipeline fractures, applying transparent soil technology for visualization. Through this approach, the erosion process within the transparent soil model was meticulously recorded using photography, enabling the quantitative analysis of collapse pit dimensions over time. Results reveal that soil erosion primarily manifests directly above the pipeline fracture, varying significantly with hydraulic conditions. In scenarios devoid of water flow within the pipeline, an increase in collapse pit depth is halted, attributed to the accumulation and blockage of soil particles at the fracture point. Contrastingly, under half-pipe and full-pipe flow conditions, the depth of the collapse pit swiftly reaches the fracture site. The flow of water notably escalates the expansion rate of the erosion pit, especially above the rupture, leading to continuous enlargement of the central area and subsequent secondary and tertiary collapses at the pit's apex. The study further identifies the impact of water flow on soil scouring near the pipeline rupture, with pronounced effects in full-pipe flow, predominantly ahead of the rupture point, and less significant impacts observed in half-pipe flow scenarios. Differential image analysis facilitated the categorization of soil into distinct zones: collapsed, loosened, stable, and eroded, with a direct correlation observed between the extent of the loosened zone and the velocity of water flow. [ABSTRACT FROM AUTHOR]

Based on the principle of water supply and demand flow and the natural flow of water, this paper analyzes the flow direction and discharge of water resources in the study area. In order to provide scientific and systematic implementation suggestions for regional water resource protection management and ecological compensation, a SWAT (Soil and Water Assessment Tool) model was constructed to quantify the water resource supply of the upper Hanjiang River basin at three spatial scales: pixel, sub-basin, and administrative unit. The water demand at the three spatial scales was calculated using the LUCC (Land Use and Land Coverage) and water consumption index. The supply and benefit zones under different spatial and temporal scales were obtained. Simultaneously, this study uncovered the spatiotemporal dynamics inherent in water resource supply and demand, alongside elucidating the spatial extent and flow attributes of water supply. The ecological compensation scheme of water resource supply–demand was preliminarily determined. The findings indicate an initial increase followed by a decrease in both the water supply and demand in the upper reaches of the Han River, accompanied by spatial disparities in the water supply distribution. The direction of the water supply generally flows from branch to main stream. The final ecological compensation scheme should be combined with natural conditions and economic development to determine a reasonable financial compensation system. [ABSTRACT FROM AUTHOR]

Riparian vegetation plays a major role in maintaining biodiversity and reducing the negative impact of nutrient leaching into aquatic ecosystems. However, the knowledge on the interactions between riparian vegetation and other environmental factors is still incomplete for planning sustainable riparian forest management. The aim of this study was to explore interactions between riparian forest ecosystem components along a small stream. Interactions between vegetation structure, chemical composition of soil and groundwater, as well as chemical element flows via litterfall and precipitation were studied in seven 50 m long transects located in the riparian forest of different characteristics along a 1.4 km river section in the northern part of Latvia. Our results showed that throughfall input of total nitrogen (TN) and potassium (K) was higher in transects with predominantly deciduous tree stands, but the concentration of TN in forest floor was higher in coniferous tree stands. At some soil layers, a positive correlation between organic soil carbon (OC) and the concentration of TN in groundwater was detected. The concentration of TN and nitrate-nitrogen (N-NO3–) in groundwater correlated positively with the deciduous tree basal area. The obtained results suggested that element flows are strongly dependent on tree species' composition and a comparatively small riparian area is able to provide diverse ecological conditions. [ABSTRACT FROM AUTHOR]

The main aim of this study is to explain periglacial processes on the summits of Mount Honaz (2571 m a.s.l.), define periglacial landforms, and determine the relationships between morphometric features and topographic factors. Mud circles, stony earth circles, non sorted steps, and non sorted stripes were identified on the summits of Mount Honaz. Pearson's correlation coefficient (r) and linear regression analyses were performed by taking metric measurements from 125 periglacial landforms to describe their morphometric features (length, width, height) of periglacial landforms and explain the relationships between them and topographic factors (elevation, slope). To explain the relationships between periglacial landforms and soil properties, soil samples from 11 periglacial landforms were taken and analysed. Periglacial landforms, which continue to develop on the summits of Mount Honaz today, have been evaluated with present climate data. Analysis of soil samples indicates a notable impact of parent material on the genesis of periglacial landforms. The high ratio of organic matter in mud circle and non sorted step landforms and the high lime ratio in stony earth circle landforms prove a strong relationship between the formation mechanisms of landforms and the soil properties. Furthermore, it is consistent with the findings obtained from the analysis that severe periglacial processes and washing and scavenging events are experienced more on the northern slopes. [ABSTRACT FROM AUTHOR]

Proper characterization of the unsaturated hydraulic properties in rocks is significant for predicting fluid flow in soil, hydrogeologic, and petroleum science and engineering problems. In this study, we contributed rigorous analysis of the unsaturated hydraulic properties of three reservoir rock samples (Berea Sandstone, Guelph Dolomite, and Indiana Limestone). An improved version of the standard evaporation method (HYPROP) was developed to cater specifically to rock samples. The improved HYPROP setup enables measurements of local water pressures within rock samples without disturbing the upper portion of the samples. The obtained results were compared with those obtained using the conventional pressure plate method and a state-of-the-art nuclear magnetic resonance (NMR) method. Observed data were analyzed in terms of four different unimodal and bimodal hydraulic functions. The HYPROP data were found to be relatively close to the pressure plate data of two carbonate rocks. The NMR-based data were reasonably consistent with the HYPROP data, with differences likely due in part to the fact that they were obtained using two different 5-cm long plugs taken from the same core. Heterogeneity along the rock cores from which the samples were taken could be a major reason for the observed differences, and hence should be considered in reservoir analyses. [ABSTRACT FROM AUTHOR]

The permeability in the natural clay layer is obviously anisotropic, and the flow of water in the pores often deviates from Darcian law. In order to analyze the effect of anisotropic non-Darcian flow on the two-dimensional consolidation of a saturated clay layer, the vertical and horizontal permeability laws of saturated clay were measured by the falling-head permeability test. It was found that the flow of water in both directions can be described by Hansbo's flow equation, and Hansbo's flow parameters in these two directions were obviously different. Then, the two-dimensional Terzaghi consolidation equations were modified considering the anisotropic Hansbo's flow and discretized into finite-element formulations. The validity of the numerical model was verified through comparison with the literature solutions. The effect of the anisotropic Hansbo's flow on the consolidation process of a two-dimensional saturated clay layer was analyzed under different lower boundary conditions. The numerical results indicated that in the initial stage of consolidation, the excess pore pressure is slightly concentrated in a specific area below the loading boundary. Moreover, variations in the lower boundary conditions have little effect on the distribution of excess pore pressure, and the influence of the different Hansbo's flow parameters in the vertical direction on the dissipation rate of excess pore pressure is not evident. However, in the middle and late stages of consolidation, the pore-water pressure with the permeable lower boundary condition is significantly lower compared to that with the impermeable lower boundary condition. Additionally, increasing the values of Hansbo's flow parameters in the vertical direction further impedes the dissipation rate of excess pore pressure, which in turn slows down the consolidation process of the clay layer. [ABSTRACT FROM AUTHOR]

This research aims to forecast, using various criteria, the flow of soil erosion that will occur at a particular geographical location. As for the training dataset, 80% of the dataset from the sample sites, four hybrid algorithms, namely heap-based optimizer (HBO), political optimizer (PO), teaching-learning based optimization (TLBO), and backtracking search algorithm (BSA) combined with artificial neural network (ANN) was used to create an erosion susceptibility model and establishes a unique and original approach. After it was confirmed to be successful, the algorithms were applied to create a susceptibility map for this area, demonstrating the integrity of the results. The AUC values were computed for every optimisation algorithm used in this study. The optimal estimated accuracy indices for populations of 450 were determined to be 0.9846 using the BSA-MLP training databases. The maximum AUC value for the HBO-MLP training databases with different swarm sizes was 0.9736. A swarm size of 350-300 is considered optimal for forecasting erosion susceptibility mapping in hybrid models. With the same swarm size constraints, the AUC value for training in the TLBO-MLP scenario was 0.996. After 150 swarm size conditions were used to train the PO-MLP model, the AUC values were 0.9845. According to these findings, the TLBO-MLP and PO-MLP algorithms worked best with populations of 50 and 150, respectively. [ABSTRACT FROM AUTHOR]

In the Russian Federation, a significant part of the forest fund territory is located on permafrost. Many regions of the country have large reserves of mature and overmature commercial forests, and a significant part of these reserves are located in hard-to-reach places, not only due to the underdeveloped road network, but also due to the difficult terrain. Currently, the vast majority of timber harvesting in Russia is carried out using modern machine complexes, mainly including wheeled forestry machines of various layouts and purposes (harvesters, forwarders, skidders, etc.). At the same time, the problem of the negative impact on the soil of forestry machines and skidding systems based on them not only remains relevant, but becomes even more acute, since the ecosystems of mountain forests, forests on the slopes of hills, etc. are among the most vulnerable, subject to water and wind erosion. As is known, the track in the soil is formed under the influence of normal load transmitted through the contact spot of the mover, as well as under the influence of the tangential force realized by the mover when moving the machine. When lifting a machine onto a slope, the tangential tractive effort of the propulsion is required than when moving across the plain. Consequently, the intensity of track formation on the slope is higher, all other things being equal. Machine systems are known where, when working on slopes, winches are used to help machines go down and up the slope. Winches can be either separate units or units integrated into the transmission of machines. The research has shown that using winches when lifting the machine onto a slope significantly reduces fuel consumption and transmission loads, which is a consequence of a decrease in the tangential tractive effort required to move the machine, realized by the engine. Then the intensity of track formation on the slope when the machine is working with a winch is less compared to working without a winch.

The Ryshkovo paleosol of the Mikulino Interglacial (MIS 5e), Late Moscow loess (MIS 6), and buried small erosional landforms were studied in the Taneyev Quarry of Kursk oblast, in the center of the East European Plain. Macro- and micromorphological and palynological analyses of the soil samples were carried out, and the OSL age and physicochemical properties were determined. The history of erosional landforms, soils, and landscapes was reconstructed on the basis of the facial analysis of the paleosol catena. It was concluded that the differentiation of the paleosol profile into the Ah–E–Bt horizons was developed during the Mikulino Interglacial, whereas the initial heterogeneity of the parent material had been formed earlier, during the Late Moscow (Saalian) Glaciation, under the impact of slope and cryogenic processes. The lithological matrix of the Ryshkovo paleosol did not remain unchanged due to the different history of interaction of eolian and slope (solifluction and colluvial) processes, initial pedogenesis, and interglacial soil formation. [ABSTRACT FROM AUTHOR]

This study examines the effect of electroosmotic (EO) and hydraulic flow on the removal of heavy metal (Pb2+, total Cr, and Fe2+) and salt (K+ and Clˉ) ions from artificially contaminated soil. For this purpose, the vertical electrokinetic (VEK) and hydraulic setups with wet sponges are introduced to reduce water consumption and avoid the accumulation of contaminants near the soil surface. In this study, during VEK experiments, different continuous and pulsed voltage gradients (i.e., 0.5, 1, and 2 V cm−1) are applied across the contaminated soil via iron mesh electrodes for 48 h, while during the hydraulic experiment, no voltage gradient is applied. The outcomes revealed that EO and hydraulic flow were directed downward from the top of the soil column, while EO flow was higher for a relatively higher voltage gradient. Therefore, the removal of cations (Pb2+ and K+) was higher than anions (total Cr and Clˉ) due to the effect of electromigration and EO flow. In contrast, under relatively low continuous and pulsed voltage gradient, the removal of anions was higher than cations due to electromigration and diffusion. In addition, during the hydraulic experiment, the removal of ions was comparatively lower than in all VEK experiments due to the low hydraulic flux. However, the accumulation of Fe2+ ions in soil increased with the intensity of voltage gradient due to the corrosion of anode during all VEK experiments, except in the case of the hydraulic experiment where no voltage gradient was applied and the removal efficiency of Fe2+ ions was 21%. [ABSTRACT FROM AUTHOR]

The two-phase seepage fluid (i.e., air and water) behaviors in undisturbed granite residual soil (U-GRS) have not been comprehensively studied due to a lack of accurate and representative models of its internal pore structure. By leveraging X-ray computed tomography (CT) along with the lattice Boltzmann method (LBM) enhanced by the Shan–Chen model, this study simulates the impact of internal pore characteristics of U-GRS on the water–gas two-phase seepage flow behaviors. Our findings reveal that the fluid demonstrates a preference for larger and straighter channels for seepage, and as seepage progresses, the volume fraction of the water/gas phases exhibits an initial increase/decrease trend, eventually stabilizing. The results show the dependence of two-phase seepage velocity on porosity, while the local seepage velocity is influenced by the distribution and complexity of the pore structure. This emphasizes the need to consider pore distribution and connectivity when studying two-phase flow in undisturbed soil. It is observed that the residual gas phase persists within the pore space, primarily localized at the pore margins and dead spaces. Furthermore, the study identifies that hydrophobic walls repel adjacent fluids, thereby accelerating fluid movement, whereas hydrophilic walls attract fluids, inducing a viscous effect that decelerates fluid flow. Consequently, the two-phase flow rate is found to increase with then-enhanced hydrophobicity. The apex of the water-phase volume fraction is observed under hydrophobic wall conditions, reaching up to 96.40%, with the residual gas-phase constituting 3.60%. The hydrophilic wall retains more residual gas-phase volume fraction than the neutral wall, followed by the hydrophobic wall. Conclusively, the investigations using X-ray CT and LBM demonstrate that the pore structure characteristics and the wettability of the pore walls significantly influence the two-phase seepage process. [ABSTRACT FROM AUTHOR]

The literature regarding how rill longitudinal profile (concave and convex) affects soil loss and flow resistance is still lacking. The only analysis available in the literature for rills is limited by the fact that measurements were performed for a unique mean slope value sp (18%). In this article, further rill measurements were conducted on a plot with sp = 15% and complex profile shapes and were used to widen the knowledge about the influence of longitudinal profile shape on rill scour, eroded volume, and flow resistance. The findings highlighted that the concave profile has a homogeneous spatial distribution of moderate scours, whereas the scours in the convex one are deeper and more confined, but they are not placed after the slope change as found for sp = 18%. The mean scour depth, which accounts for the discharge and profile shape effects, is not (concave) or is weakly (convex) related to the flow discharge. The concave profile determined a reduction of approximately 57% of the total eroded volume when compared with the convex profile shape, confirming that a concave hillslope limits erosive phenomena. Finally, the flow resistance equation guaranteed a precise estimation of the Darcy–Weisbach friction factor. [ABSTRACT FROM AUTHOR]

Subsurface tile drainage systems are common in agricultural regions of the Midwestern United States. Drainage systems remove excess water from the surface and soil profile of agricultural fields, allowing crop production in previously unsuitable locations. However, these systems impact watershed hydrology and could influence flooding events. Therefore, this study aimed to determine whether tile drainage systems influence downstream flood days in a Midwestern agricultural watershed, specifically the Skunk Creek watershed. The Soil and Water Assessment Tool (SWAT) model was used to simulate the hydrologic processes of the Skunk Creek Watershed for an 18-year period (2004-2021). The model was calibrated and validated using observed daily streamflow data with the SWAT Calibration and Uncertainty Program (SWAT-CUP) software and through the manual modification of missed precipitation data. Three tile drainage scenarios--ranging from 15% to 75% tile-drained agricultural land--were individually incorporated into the model. Results indicated that with increased tile drainage, surface runoff, groundwater flow, deep aquifer recharge, and percolation decreased, whereas lateral soil flow, tile flow, evapotranspiration, and water yield increased. A comparison of tile drainage scenarios suggests that increasing the area of tile-drained agricultural land decreases total flood days. However, the impact of tile drainage systems on downstream peak flood flows varied by event, with large precipitation events initiating flood days across all scenarios. While tile flow decreased flood days on a daily time step, flash floods might have occurred on a subdaily time step but were not captured in this study. Future studies can replicate the approach with a sub-daily time step for simulating hourly flood events with various tile drainage scenarios. [ABSTRACT FROM AUTHOR]

The hysteresis response of tree sap flux (SF) to its main driving factor of incoming short‐wave radiation (Rsi) has been widely reported, affecting the accuracy of sap flux and transpiration estimates in forest ecosystems. The diurnal cycle of SF usually lags the Rsi cycle by certain hours, thereby generating a closed counterclockwise hysteresis pattern. However, a few studies have reported that diurnal SF cycle may advance Rsi cycle, and such a response pattern has not been fully explored. In this study, we reported a rarely seen crossed hysteresis response pattern of SF to Rsi in 1/3 trees of a young temperate pine forest. We found that the diurnal SF cycle advances Rsi cycle especially in the morning induced by the early stomatal closure, thereby generating the crossed hysteresis response of SF to Rsi. We also proposed a method to quantify the magnitude of hysteresis (Ahys) for both the crossed and closed hystereses. Our analysis suggests that a lower Ahys of two time series results in (a) a larger crossing degree of hysteresis, and (b) a stronger linear correlation between the two time series. The seasonal variation of soil water content can explain the variation in Ahys for the hysteresis response of SF to Rsi, and the crossed hysteresis of SF is more likely to occur under water stress conditions. This study contributes to advancing our understanding of forest transpiration and how forests may respond to drought stress, which are expected to become more frequent and longer under future climate change. Plain Language Summary: Sap flux (SF) is widely used as a surrogate of transpiration in field studies. It is broadly reported that the diurnal cycle of SF lags its driving force—incoming short‐wave radiation (Rsi). Correspondingly, a closed counterclockwise loop appears when plotting SF against Rsi on a diurnal basis. Such phenomenon is widely identified as a hysteresis response of SF to Rsi. In our study, we reported that the diurnal SF cycle can advance the Rsi cycle especially in the morning, with a crossed SF‐Rsi hysteresis loop emerging. The crossed hysteresis is more complex in terms of the direction and pattern than the closed hysteresis loop; we further found the crossed hysteresis pattern contributes to reducing the magnitude of hysteresis and improving the correlation between SF and Rsi. We developed a method to quantify the magnitude for both the crossed and closed hystereses. We found that the closure of stomatal conductance drives the early decline of the diurnal SF cycle, resulting in the crossed hysteresis. We also found that soil water content plays an important role in controlling the seasonal variation of hysteresis and the crossed hysteresis is more likely to emerge in water stress conditions. Key Points: A novel crossed hysteresis response of sap flux to solar radiation is reported and investigatedThe early stomatal closure drives the variation of the hysteresis pattern of forest transpirationSoil water stress induces the seasonal variation of the sap flux‐radiation hysteresis [ABSTRACT FROM AUTHOR]

Preferential flow (PF) processes are governed by subsurface soil structures at various scales. Still, model validation and mechanistic understanding of PF are very lacking. We hypothesize that PF at hillslope and larger scales cannot be described and quantified when neglecting small‐scaled spatially variable processes and simplifying the model dimensionality. The objective was to learn from comparing simulation results of multidimensional (1D, 2D, and 3D) and multiscale (pedon, catena, and catchment) modeling approaches with comprehensive datasets, and so as to evaluate PF simulations based on the Richards' equation (solved by the HYDRUS software). Results showed limited alignment between 1D simulations and soil moisture data, mainly affected by vertical changes in porosity, permeability, and precipitation features. 2D and 3D simulations outperformed 1D models. 3D simulations provided satisfactory description of PF dynamics at the pedon scale, considering accurate representations of soil and bedrock structures for three dimensions (vertical, horizontal, and surrounding area). In 2D simulations at the pedon scale, models incorporating dual‐porosity and anisotropy of soils yielded more accurate predictions of water dynamics than single‐porosity and isotropic models. Furthermore, the application of 2D simulation at the catena scale identify PF pathways owing to the enhanced representation of the hydraulic connectivity between different locations along the slope. The results confirmed the significance of multidimensional and multiscale modeling approaches for PF simulations in hillslope hydrology. Considering the complexity and parameterization of 2D and 3D "bottom‐up" physically based models in representing spatial variability within and between soil profiles and/or underlying bedrock geology, the results contribute to creating a modeling framework applicable to identify the PF processes and thus their implications in managing water resources. Core Ideas: The 3D model was better than 2D model to detect the preferential flow.A dual‐porosity or anisotropy model produced more accurate predictions than a single‐porosity or isotropy model.A model domain that considered fractured bedrock performed better than without it. [ABSTRACT FROM AUTHOR]

The Peters–Durner–Iden (PDI) model system for describing soil hydraulic properties (SHP) has been developed over a decade. Inspired by Rien van Genuchten's seminal work, the PDI system focuses on an efficient and simple parameterization of water retention curves and hydraulic conductivity curves (HCC) across the entire soil moisture spectrum. By combining capillary and non‐capillary components for water retention and conductivity, it aims to reconcile mathematical simplicity and insights on water adsorption and film flow in soils. Recent developments have reduced the number of free parameters of the conductivity model to zero, enhancing the model's applicability in cases of limited data availability. The first reduction was achieved by a prediction of absolute non‐capillary conductivity based on the consideration of film and corner flow on the pore scale, and the second by a prediction of absolute capillary conductivity by a capillary bundle model. This allows a complete characterization of SHP over the entire moisture range with only four retention curve parameters. The inclusion of a maximum pore size in the capillary conductivity model prevents an unrealistic drop of the HCC near saturation. This paper provides a comprehensive overview of the PDI model system, emphasizing its conceptual features and mathematical details. An Excel sheet and a Python code stored in a repository are provided for accessibility. Core Ideas: Compact and comprehensive mathematical overview of the current PDI system.The model integrates elements of capillary and non‐capillary soil water storage and conductivity in a simple manner.Hydraulic conductivity can be completely predicted from the retention curve.Improved applicability in cases where conductivity data are scarce or available only in a limited moisture range. [ABSTRACT FROM AUTHOR]

Earthworms and plant roots are vital for macropore formation and stabilization. The organo‐mineral coating of biopore surfaces also regulates macropore‐matrix mass exchange during preferential flow. The influence of finer‐textured burrow coatings on macroscopic soil properties during shrinkage could potentially be assessed by upscaling pore‐scale hydraulic and mechanical simulations. The aim was to investigate the influence of micro parameters (particle size, stiffness, and bond strength) on macro parameters (i.e., shrinkage curve and soil hydraulic properties). Drainage experiments and simulations were carried out using biopore‐coated clod‐size samples compared to those without coating. Simulations were performed using a two‐phase pore‐scale finite volume coupled with discrete element model (DEM‐2PFV). The structural dynamics was characterized by analyzing the pore volume and soil shrinkage curve obtained from numerically determined data. The soil hydraulic parameters were described using uni‐ and bimodal van Genuchten (vG) functions. The drainage simulations revealed hydro‐mechanical dynamics characterized by Braudeau‐shrinkage curve subdomains: The matrix‐only samples, with lower particle bond strength, exhibited relatively higher shrinkage. The coated samples, with higher particle stiffness and bond strength, displayed greater hydro‐mechanical stability. The numerically determined initial value of the saturated hydraulic conductivity (Ks) was about 70 times larger for matrix‐only samples than for coated samples. As expected, for the nonrigid soil structures, constant Ks, α, and n values for bimodal vG model resulted in prediction errors. Upscaling DEM‐2PFV pore‐scale model outcomes quantifies micro‐coating effects on macro hydro‐mechanics. This yields void ratio‐based soil water retention and hydraulic conductivity functions, advancing macroscopic soil hydraulic models and enhancing structured soil flow and transport descriptions. Core Ideas: Constant hydraulic properties led to prediction errors in nonrigid soil structures.Upscaling pore‐scale simulations quantified shrinkage and water retention curves.Coated biopore surfaces increase soil horizontal hydro‐structural stability. [ABSTRACT FROM AUTHOR]

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Under a warming climate, occurrences of wildfires have been increasingly more frequent in boreal and arctic forests during the last few decades. Wildfires can cause radical changes in the forest ecosystems and permafrost environment, such as irreversible degradation of permafrost, successions of boreal forests, rapid and massive losses of soil carbon stock, and increased periglacial geohazards. Since 2016, we have gradually and more systematically established a network for studying soil nutrients and monitoring the hydrothermal state of the active layer and near-surface permafrost in the northern Da Xing'anling (Hinggan) Mountains in Northeast China. The dataset of soil moisture content (0–9.4 m in depth), soil organic carbon (0–3.6 m), total nitrogen (0–3.6 m), and total phosphorus and potassium (0–3.6 m) have been obtained by field sampling and ensuing laboratory tests. Long-term datasets (2017–2022) of ground temperatures (0–20 m) and active layer thickness have been observed by thermistor cables permanently installed in boreholes. The present data can be used to simulate changes in permafrost features under a changing climate and wildfire disturbances and to explore the changing interactive mechanisms of the fire-permafrost-carbon system in the hemiboreal forest. Furthermore, can provide baseline data for studies and action plans to support the carbon neutralization initiative and assessment of ecological safety and management of the permafrost environment. This dataset can be easily accessed from the National Tibetan Plateau/Third Pole Environment Data Center (https://doi.org/10.11888/Cryos.tpdc.300933 , Li and Jin, 2024). [ABSTRACT FROM AUTHOR]

The drained shear strength of overconsolidated glaciolacustrine clays in the Seattle area can range from the overconsolidated peak to residual strength depending on its geologic history, depth, softening, prior shear displacements, size of excavation, and application, e.g., long-term cut slope versus short-term braced excavation. An inverse analysis of slope failures shows the mobilized shear strength for cut slopes in the overconsolidated and sparsely jointed Qvgl glaciolacustrine clay ranges from the fully softened strength to in between fully softened and residual strength depending on the level of jointing, prior shear displacements, assumed piezometric levels, and Atterberg limits used in the analysis. Conversely, an inverse analysis of a 2011 slope failure in the frequently jointed and random slickensided overconsolidated Qpgl glaciolacustrine clay shows the mobilized shear strength for this deposit near residual to in between residual and fully softened strengths because of repeated glaciation cycles, softening, and local shear displacements due to glacial bulldozing, solifluction, and high lateral stresses. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to reduce the dimensionality of unknown coefficient vectors of finite-element (FE) solutions in two-grid (CN) FE (TGCNFE) format for the nonlinear unsaturated soil water flow problem by using a proper orthogonal decomposition (POD) and to design a new reduced-dimension iteration TGCNFE (RDITGCNFE). For this objective, a new time semi-discrete CN (TSDCN) scheme for the nonlinear unsaturated soil water flow problem is first designed and the existence, stability, and error estimates of TSDCN solutions are demonstrated. Subsequently, a new TGCNFE format for the nonlinear unsaturated soil water flow problem is designed and the existence, unconditional stability, and error estimates of TGCNFE solutions are demonstrated. Next, a new RDITGCNFE format with the same FE basis functions as the TGCNFE format is built by the POD method and the existence, unconditional stability, and error estimates of RDITGCNFE solutions are discussed. Ultimately, the rightness of theory results and the superiority of the RDITGCNFE format are verified by two sets of numerical tests. It is worth noting that the RDITGCNFE format differs completely from all previous reduced-dimension methods, including the authors' previous works. Therefore, the study of this paper can not only provide a new theoretical method for the dimensionality reduction of numerical models for nonlinear problems but also provide an algorithm implementation technology for the numerical simulation of practical engineering problems. [ABSTRACT FROM AUTHOR]

Climate prediction is of great significance to the prevention of drought and flood. "Ground-synoptic" map is a method for short-term climate prediction. The main content of this method is "Geothermal Vortex"(GV). Therefore, some characteristics of 3.2 m soil temperature anomaly (hereinafter abbreviated as T′ 3.2 m) and GV are analyzed by using the data of monthly soil temperature at the depth of 3.2 m from 1980 to 2017 in China. Results show that there are regional differences in the frequency of positive anomaly. Overall, there are more positive anomalies in southern China and fewer in Western China. Soil temperature anomaly has good memory, the shortest being 5 months and the longest being nearly 2 years. Moreover, results show the nonuniform distribution of memory duration and decreases from northwest to southeast as a whole. Statistical analysis of GV shows that the average life cycle of each GV is 9.7 months, with an average horizontal scale of 604 km and a characteristic scale of 2.4 cm/s. Spatially, the GV scale is largest in Northwest, with a horizontal scale of 1087 km, and the GV appear most frequently in North China. The central location of GV is uneven, mainly in the central area with strong crustal activity and large absolute vertical deformation rate or in the high value area of soil heat flow. [ABSTRACT FROM AUTHOR]

In order to achieve the resource utilization of high moisture content shield soil in underground engineering and explore the feasibility of using geopolymer materials to solidify shield soil, this paper adopts slag-base geopolymer to solidify shield soil. By studying the influences of alkali activator modulus, mineral ratio, alkali activator dosage and temperature on unconfined compressive strength and engineering performance of different types of shield-cured soil, the design of cured soil mix proportion was determined. The influence of geopolymer content on water stability of cured soil was studied. Microscopic analysis of shield-cured soil using SEM to reveal the solidification mechanism. The results show that under the proposed water solid ratio in the test, the two kinds of fluid shield-cured soil with different soil properties have good mechanical and engineering properties. The aggregate of slag base produces amorphous gel, which enhances the cementation and compactness between soil particles. The unconfined compressive strength of shield-cured soil with 22% dry soil mass as cementing agent can reach 5.38 MPa in 28 d under standard curing, 8.08 MPa under 40 °C curing, and the water stability coefficient can reach 0.98. [ABSTRACT FROM AUTHOR]

In this study, we investigate the combined effect of different rainfall‐runoff event types and antecedent soil moisture (ASM) on runoff processes in the headwater elementary discharge area of a small forested upland catchment. The study focuses on (i) the relationship between soil moisture thresholds and runoff generation; (ii) the combined effect of ASM and tree vicinity and (iii) the relationship between different rainfall‐runoff event types and different types of runoff (baseflow and stormflow). The results suggest that ASM has a strong impact on local runoff generation processes. Soil water content (35%–36%) threshold exceedance was related to stormflow runoff generation caused by the activation of quick preferential flow paths in the soil during storm events, especially in the upper and the deepest soil layers. At the same time, unexpected non‐linear increases in baseflow runoff ratios were documented during dry, precipitation‐free, periods and when the 31%–34% soil moisture threshold was exceeded, presumably due to the hydrological connection of farther slope areas during these conditions. Multiple stormflow periods, which exhibited the lowest runoff coefficient, were the most significant events in terms of water retention and soil water recharge due to increased vertical hydrological connectivity enabling more rapid transport to deeper soil layers. However, this rainfall type occurred least often over the study period. The important role of forest stands (individual trees) in creating spatial patterns of soil moisture and preferential infiltration paths to deeper soil layers was also confirmed. These results contribute towards a better conceptualisation of hydrological behaviour in elementary headwater discharge areas and highlight the potential dangers associated with expected increases in extreme weather events. [ABSTRACT FROM AUTHOR]

The relationship between catchment storage and discharge is nonlinear. The dynamicity of this relationship is dependent on the distance of the storage measurement from the stream, the depth of the soil moisture (SM) measurement, antecedent SM storage, and precipitation characteristics. Understanding the relative influence of these factors is critical for interpreting runoff generation processes and predicting discharge. In this study, we used a hysteresis index approach and analysed the nonlinear dynamics of catchment storage–discharge relationship across points, hillslope and catchment scales, and their controlling factors. A small headwater forested catchment located in the southern part of the Sierra Nevada region, California, was selected as a case study. In this Mediterranean catchment, the anticlockwise class IV hysteresis loop, indicating an earlier discharge peak than SM, was observed as a prevalent hysteresis class across all the scales, irrespective of seasons (i.e., dry vs. wet) and years (i.e., normal vs. drought). A few clockwise hysteresis loops were observed at the shallow depths (10 and 30 cm) of upslope and lower slope topographic positions. Further, we found a shorter lag time between SM peak to discharge peak at 60 and 90 cm soil depths during the wet season, and during the drought period. The shorter lag at the deeper depth was due to the presence of subsurface flow during high antecedent SM storage conditions and preferential flow through the soil pores during the drought periods. The variability in hysteresis at catchment and hillslope scales was controlled by peak rainfall intensity and antecedent SM storage. However, rainfall characteristics (intensity and depth) were major governing factors for most of the point scale locations. Overall, the current study highlighted the role of SM sensor's location in characterizing storage–discharge behaviour. [ABSTRACT FROM AUTHOR]

Rapid and unstable preferential flow has a significant impact on soil carbon cycle. This review aims to explore the effects of preferential flow on the soil carbon cycle and indicate its characteristics and ecological responses in different ecosystems. This study concluded that preferential flow influences soil carbon cycle through various mechanisms, such as facilitating rapid transport of dissolved organic matter, shaping the distribution and aggregation patterns of soil organic carbon, and enhancing soil microbial activity and organic matter decomposition. The characteristics of preferential flow include surrounding characteristics, rapid non-equilibrium infiltration characteristics, fluctuating characteristics, universal characteristics, lateral infiltration characteristics. Those characteristics could also affect the spatial distribution of soil organic carbon. In addition, this review examines the phenomenon of preferential flow in farmland, forest, wetland, desert, and permafrost ecosystems. Finally, we provide insightful perspectives on future research directions, emphasizing the importance of advancing our understanding of preferential flow mechanisms. It also serves as a valuable resource for future research aimed at unraveling the underlying mechanisms of preferential flow and developing effective soil carbon management strategies. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Cyclic stress-dilatancy relations and plastic flow potentials for soils based on hypothesis of complementarity of stress-dilatancy conjugates" published in Acta Geotechnica. The correction states that figures 5, 6, and 18 in the original publication were published incorrectly and provides the correct versions of these figures. The correction is made by Anteneh Biru Tsegaye. Springer Nature, the publisher, remains neutral regarding jurisdictional claims and institutional affiliations. [Extracted from the article]

Microbial-induced carbonate precipitation (MICP) is a promising process with applications in various industries, including soil improvement, bioremediation, and concrete repair. However, comprehensive bibliometric analyses focusing on MICP research in hydrodynamics are lacking. This study analyses 1098 articles from the Scopus database (1999–2024) using VOSviewer and R Studio, identifying information on publications, citations, authors, countries, journals, keyword hotspots, and research terms. Global participation from 66 countries is noted, with China and the United States leading in terms of contributions. The top-cited papers discuss the utilisation of ureolytic microorganisms to enhance soil properties, MICP mechanisms, concrete deterioration mitigation, soil and groundwater flow enhancement, biomineral distribution, and MICP treatment effects on soil hydraulic properties under varying conditions. Keywords like calcium carbonate, permeability, and Sporosarcina pasteurii are pivotal in MICP research. The co-occurrence analysis reveals thematic clusters like microbial cementation and geological properties, advancing our understanding of MICP's interdisciplinary nature and its role in addressing environmental challenges. [ABSTRACT FROM AUTHOR]

Finding effective ecosystem services (ESS) management practices to counteract land degradation and poverty is becoming increasingly urgent in the Ethiopian highlands, where livelihood security is strongly dependent on local ESS, particularly those provided by water and soil. In this paper, we test the effects of widely implemented soil and water conservation (SWC) interventions on storm flow and sediment concentration in the Debre Mawi watershed (representative of watersheds in the upper Blue Nile basin and Ethiopian highlands). The SWC interventions were tested with a Parameter Efficient Distributed (PED) model. The PED model simulates saturation excess runoff from degraded and saturated valley bottoms, and base and interflow from hillsides. The model was calibrated with observed runoff and sediment data in a 95-ha subcatchment. We found that the PED model simulated the discharge and soil loss well by decreasing the proportion of degraded lands due to installing SWC practices. The results show that four years after the implementation of SWC practices, the infiltration of rainwater was improved in 53% of the degraded lands. Thus, installing SWC practices on hillsides where infiltration is limited is most beneficial and will result in greater water availability during the dry phase, especially in locations where volcanic dikes block the lateral flow. [ABSTRACT FROM AUTHOR]

The occurrence and development of rill erosion depends on the hydraulic characteristics of water flow and underlying soil surface features. Our experiments include one-rainfall-intensity treatments (2.0 mm min−1) and various microtopographic levels based on different tillage practices with smooth slope (CK), artificial digging (AD), and ridge tillage (RT) on a 15° slope. The results indicate the following: (1) The soil roughness index values were in the order of CK < AD < RT, and the spatial variability of different tillage practices had strong autocorrelations during different rill erosive stages. The codomain values decreased with the increase in microtopography. (2) The multifractal dimension values of tillage practices in various erosive stages were in the order of RT > AD > CT. The microtopography of different tilled slopes showed strong multifractal characteristics, and the multifractal characteristics were stronger as the microrelief heterogeneity increased. For the CK slope, the generalized fractal dimension span (ΔD) ranged between 0.0019 and 0.0058. For the AD slope, ΔD was between 0.2901 and 0.5112. And, for the RT slope, ΔD was between 0.4235 and 0.7626. (3) With the evolution of rill erosion, the flow pattern on different tilled slopes changed from subcritical transition flow to supercritical transition flow. (4) Soil roughness index and ΔD had good correlations with hydrodynamic parameters. The stronger the erosive energy of runoff was, the higher the spatial heterogeneity of microtopography was. This study is expected to provide a theoretical basis for revealing the hydrodynamic mechanism of rill erosion in slope farmland. [ABSTRACT FROM AUTHOR]

Maritime Antarctica (M.A.) contains the most extensive and diverse lithological exposure compared to the entire continent. This lithological substrate reveals a rich history encompassing lithological, pedogeomorphological, and glaciological aspects of M.A., all influenced by periglacial processes. Although geophysical surveys can detect and provide valuable information to understand Antarctic lithologies and their history, such surveys are scarce on this continent and, in practice, almost non-existent. In this sense, we conducted a pioneering and comprehensive gamma-spectrometric (natural radioactivity) and magnetic susceptibility (κ) survey on various igneous rocks. The main objective was to create ternary gamma-ray and κ maps using machine learning algorithms, terrain attributes, and a nested-leave-one-out cross-validation method. Additionally, we investigated the relationship between the distribution of natural radioactivity and κ to gain insights into pedogeomorphological and periglacial processes and dynamics. For that, we used proximal gamma-spectrometric and κ data in different lithological substrates associated to terrain attributes. The geophysical variables were collected in the field from various lithological substrates, by use field portable equipment. The geophysical variables were collected in the field from various lithological substrates using portable equipment. These variables, combined with relief data and lithology, served as input data for modeling to predict and spatially map the content of radionuclides and κ by random forest algorithm (RF). In addition, we use nested-LOOCV as a form of external validation in a geophysical data with a small number of samples, and the error maps as evaluation of results. The RF algorithm successfully generated detailed maps of gamma-spectrometric and κ variables. The distribution of radionuclides and ferrimagnetic minerals was influenced by morphometric variables. Nested-LOOCV method evaluated algorithm performance accurately with limited samples, generating robust mean maps. The highest thorium levels were observed in elevated, flat, and west beach areas, where detrital materials from periglacial erosion came through fluvioglacial channels. Lithology and pedogeomorphological processes-controlled thorium contents. Steeper areas formed a ring with the highest uranium contents, influenced by lithology and geomorphological-periglacial processes (rock cryoclasty, periglacial erosion, and heterogeneous deposition). Felsic rocks and areas less affected by periglacial erosion had the highest potassium levels, while regions with sulfurization-affected pyritized-andesites near fluvioglacial channels showed the lowest potassium contents. Lithology and pedogeochemical processes governed potassium levels. The κ values showed no distinct distribution pattern. Pyritized-andesite areas had the highest levels due to sulfurization and associated pyrrhotite, promoting iron release. Conversely, Cryosol areas, experiencing freezing and thawing activity, had the lowest κ values due to limited ferrimagnetic mineral formation. Lithology and pedological-periglacial processes in Cryosols played a significant role in controlling κ values. In regions characterized by diverse terrain attributes and abundant active and intense periglacial processes, the spatial distribution of geophysical variables does not reliably reflect the actual lithological composition of the substrate. The complex interplay of various periglacial processes in the area, along with the morphometric features of the landscape, leads to the redistribution, mixing, and homogenization of surface materials, contributing to the inaccuracies in the predicted-spatialized geophysical variables. [ABSTRACT FROM AUTHOR]

The primary factors controlling regional gully distribution in mountainous areas are poorly understood. To investigate the spatial characteristics and controlling factors of mountainous gullies at the regional scale, kernel density (KD) estimation, semivariogram, and Geodetector methods were used based on 11 environmental factors of gullies in the Yuanmou dry-hot valley. The results show that (a) gullies are widely but unevenly distributed in the valley, with an average KD of 1.155 km/km2, and gully distribution displays spatial autocorrelation with environmental factors over diverse scales; (b) relief amplitude (Ra), landform type, and slope are the primary factors controlling gully distribution, and land use type, precipitation, and elevation are also important factors; and (c) a high risk of gully erosion occurs in areas with an elevation of more than 1437 m, slope greater than 15°, and Ra greater than 173 m, with grassland vegetation or luvisols and cambisols soil types. These results will not only help to understand the spatial pattern and formation mechanism of gullies at the macroscopic scale but also provide a scientific reference for regional gully management. [ABSTRACT FROM AUTHOR]

Soil invertebrates are a major element of soil biodiversity, which play critical roles in soil ecosystems. However, the impacts of urban landscapes on the genetic diversity and gene flows of soil arthropods remain unclear.Here, we studied the genetic diversity and gene flow of Scolopendra mutilans in an urban area using mitochondrial Cytb genes and eight novel microsatellite loci.A total of 22 haplotypes and 24 variation sites were identified based on 556 bp Cytb sequences from 84 individuals of five populations in Nanjing, Jiangsu Province, China. There were 5.63–8.00 alleles in the average of eight microsatellites found in the S. mutilans arthropod populations, which showed high genetic diversity in urban landscapes. There was no correlation between the natural habitat size and genetic diversity of S. mutilans. The global Fst value based on microsatellites was 0.115, which suggested a medium genetic differentiation and population isolation.The genetic structure of S. mutilans might be affected by urbanisation, as urban patches might hinder gene flow between populations. Ecological corridors preserved in cities might serve as pathways for population migration, which increases gene flow. The gene flows of S. mutilans might not be hindered by natural barriers within cities, as there were strong relationships between populations separated by rivers.These results may contribute to the conservation of S. mutilans diversity and elucidate its adaptation to urbanisation. [ABSTRACT FROM AUTHOR]

This paper reports a field case of the excavation of a large-scale basement parallel to twin existing shield-driven tunnels in soft soils. A comprehensive field monitoring program was conducted to measure the performances of the shield tunnels during excavation. The trapezoid-shaped basement with an excavation area of 26,982 m2 was excavated at the side of twin existing shield tunnels using a bottom-up excavation sequence. The tunnel horizontal and vertical displacements, and the tunnel convergence, were extensively measured. Based on field observations, the existing shield tunnels developed horizontal movements toward the excavation side, and settlements in the shield tunnels were observed due to the stress relief of the excavation of the large basement. The tunnel rings within the excavation width generally experienced horizontal elongation as a result of the reduction in the lateral earth pressure because of excavation. During the excavation of the elevator shaft, soil flow occurred, which resulted in a sudden and continuous increase in the tunnel horizontal displacements, tunnel settlements, and tunnel convergences. The down track suffered more serious adverse impacts than the up track, with eight leakages and 61 cracks observed in the down track. The newly induced cracks mainly occurred in a range within the excavation width, and were generally consistent with the distributions of the tunnel horizontal displacement and tunnel convergence. The measured data for the normalized tunnel horizontal and vertical displacements mainly fell between δh/|δhm| = δv/|δvm| − 0.5 and δh/|δhm| = δv/|δvm| + 0.4, and it was difficult to establish a direct linear relationship between them. However, a fairly good relationship between the tunnel convergence and horizontal displacement can be observed, the measured data mainly falling along δc/|δcm| = δh/|δhm|. An approximately linear relationship can be roughly found between the normalized tunnel vertical displacement and the tunnel convergence. The data mainly fell between δc/|δcm| = δv/|δvm| + 0.2 and δc/|δcm| = δv/|δvm| − 0.3. [ABSTRACT FROM AUTHOR]

Helical anchors have been extensively employed as foundation systems for carrying tension loads due to their installation efficiency and large uplift capacity. However, the installation influences of helical anchors are still not well understood, especially for multi-helical anchors. The matrix discrete element method was used to model the process of helical anchor penetration and pull-out in dense sand to investigate the effects of the anchor geometry and advancement ratio (AR, the relative vertical movement per rotation) on soil disturbance, the particle flow mechanism, and the uplift capacity. For shallow helical anchors, the overall disturbance zone is the shape of an inverted cone after installation, while for deep helical anchors, it is funnel-shaped. The advancement ratio has significant effects on the soil particle movement and uplift capacity of helical anchors. The soil particle flow mechanism around helical plates has been identified for single-helix anchors at various advancement ratios, and for double-helix anchors, the influence of the top plate on particle movement during installation was investigated. The uplift capacities of both single- and double-helix anchors increase with the decrease in the AR (AR = 0.5~1), and the influence decreases with the anchor embedment ratio. The efficiency of double-helix anchors induced by installation is close to 1 at pitch-matched installation (AR = 1), indicating that the impact of the top plate during installation is minimal in this case. [ABSTRACT FROM AUTHOR]

Direct information about the soil structure can be obtained with X‐ray computed microtomography, and the imaged macropore networks can be used as geometries in the lattice Boltzmann flow simulations. This method has not been widely applied for near‐saturated flows due to methodological issues related to diffuse‐interface two‐phase flow simulations in samples with limited resolution. Here, a simple pore‐scale lattice Boltzmann approach to simulate steady‐state water flow in partially saturated soil macropore networks that circumvents these problems is presented. The actual simulation is preceded by the determination of water–air distribution, for example, by using morphological operations. Flow through the water‐filled part of the pore space is done by using no‐slip conditions at water–solid boundaries and slip conditions at water–air interfaces. The method was tested by simulating film flow over a solid surface, and the numerical results are shown to agree with the analytical expression available for this flow geometry. The method is further tested, and its use is demonstrated with real tomographic reconstructions of clay soil samples. Core Ideas: Lattice Boltzmann method was used to simulate near‐saturated flow in the imaged soil macropore system.The approach uses static water–air distribution in soil macropores that were determined by a morphological model.Slip boundary condition at water–air interfaces was realized with a bounce‐back rule from a moving boundary.The approach reduces the computational costs for simulating water flow in pore networks at near‐saturated condition. [ABSTRACT FROM AUTHOR]

Soil water sustains life on Earth, and how to quantify water equilibrium and kinetics in soil remains a challenge for over a century despite significant efforts. For example, various models were proposed to interpret non‐Darcian flow in saturated soils, but none of them can capture the full range of non‐Darcian flow. To unify the different models into one overall framework and improve them if needed, this technical note proposes a theory based on the tempered stable density (TSD) assumption for the soil‐hydraulic property distribution, recognizing that the underlying hydrologic processes all occur in the same, albeit very complex and not measurable at all the relevant scales, soil‐water system. The TSD assumption forms a unified fractional‐derivative equation (FDE) using subordination. Preliminary applications show that simplified FDEs, with proposed hydrological interpretations and TSD distributed properties, effectively capture core equilibrium and kinetic water processes, spanning non‐Darcian flow, water retention, moisture movement, infiltration, and wetting/drying, in the soil‐water system with various degrees and scales of system heterogeneity. Model comparisons and evaluations suggest that the TSD may serve as a unified density for the properties of a broad range of soil‐water systems, driving multi‐rate mass, momentum, and energy equilibrium/kinetic processes often oversimplified by classical models as single‐rate processes. Plain Language Summary: This technical note introduced a framework aimed at unifying and enhancing existing theories/models for interpreting various soil‐water processes in soils. A unified physical law, termed the "tempered stable density law," was assumed for soil‐water properties, leading to a unified model which well captures the core soil water processes that have been modeled (many times inefficiently) by tens of different and sometimes competing theories/models over the past century. This unified theory/model has the potential for expansion to other land‐surface equilibrium and kinetic processes that cover a wide range of spatiotemporal scales and share a similar dynamic nature as water in soils. Key Points: A tempered stable law with subordination built a unified model governing water equilibrium and kinetics in saturated/unsaturated soilsFractional‐derivative equations fitted soil‐water data sets, such as non‐Darcian flow, as well as or better than classical modelsThe assumed tempered stable density distribution for soil‐hydraulic properties led to multi‐rate moisture dynamics [ABSTRACT FROM AUTHOR]