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Polarimetric imaging technology plays a crucial role in de-scattering, particularly in the field of underwater image restoration. Circularly polarized light (or the underlying circular polarization memory effect) has been proven to better preserve the polarization characteristics of detected light. Utilizing circularly polarized light as illumination can further enhance the effectiveness of polarization de-scattering techniques. After rethinking the advantages of circularly polarized light, this paper proposes a new method for underwater polarimetric imaging restoration that leverages the pre-processing of polarized sub-images and the correlation of polarization characteristics (i.e., the angle of polarization and degree of polarization). Additionally, to address the challenge of selecting scattering light parameters due to uneven light fields in target scenes, an intensity adjustment factor search algorithm is designed. This algorithm eliminates the need for the manual selection of scattering light parameters, effectively solving the problem of uneven illumination in restoration results. A series of experiments demonstrate that, compared to traditional algorithms, the proposed method offers superior detail restoration and higher robustness. [ABSTRACT FROM AUTHOR]

Soil erosion has become a serious ecological problem hindering the agricultural and economic development in Northeast China. Soil aggregates are basic units that regulate soil fertility and microbial activity. However, there have been few reports on the role of soil erosion in regulating the microbial diversity, multiple ecosystem services, and functions (multifunctionality) of soil aggregates. In this study, we investigated the effects of soil erosion on microbial diversity and the activities of various extracellular enzymes associated with soil aggregates by using Mollisol soil in Northeastern China at different positions of a slope, and how soil erosion affects soil multifunctionality indexes obtained by normalized calculation of soil enzyme activities. The results showed that soil erosion could reduce the physicochemical properties, soil enzyme activity, and microbial diversity of the aggregates, resulting in accumulation of aggregate nutrients and increase in microbial diversity and enzyme activity in the sedimentation area. Compared with smaller soil aggregates, larger soil aggregates had higher nutrient content, enzyme activity, and microbial diversity. However, with the intensification of soil erosion, the differences in microbial diversity and soil enzyme activities among different sizes of aggregates were reduced. Soil erosion also significantly reduced soil multifunctionality (p < 0.001). The multifunctionality of 2000–250 μm, 250–53 μm, and <53 μm aggregates respectively declined from 0.52, 0.20, and 0.08 (no erosion sites) to −0.17, −0.66, and −0.77 (heavy erosion sites). Additionally, microbial diversity was found to have a linear positive correlation with soil multifunctionality (R2 = 0.23, p < 0.01). Structural equation modeling and random forest analysis revealed that soil organic carbon and aggregate water stability are main predictors of soil multifunctionality. Furthermore, soil physicochemical properties had a greater influence on soil multifunctionality than microbial diversity. Collectively, our results demonstrate that soil erosion negatively affects the structure, resource effectiveness, and microbial activity of soil aggregates, thereby reducing to differential soil multifunctionality. [ABSTRACT FROM AUTHOR]

Rock fragments play a pivotal role in influencing slope erosion processes, attracting increasing scientific interest and growing concerns regarding their potential impacts on erosion. This paper reviews the studies published in recent decades concerning the various impacts of rock fragments on soil erosion processes by water, highlighting the research gaps and outstanding challenges in exploring the erosion evolution process involving rock fragments. Systematic studies and illustrative examples have shown that the impacts of rock fragments characteristics (such as coverage, content, size, position, shape, and spatial heterogeneity) on erosion processes are complex and inconsistent (positive/negative). This uncertainty can be attributed to the intricate erosion process and the diverse rock fragment characteristics, complicating the development of accurate erosion prediction models. Current models predominantly focus on rock cover and often ignore the essential factors including rock size, position, and shape, thus impeding the precise understanding of how rock fragment characteristics specifically affect soil erosion within existing erosion models. Furthermore, this review discusses the perspectives for enhancing the research on rock fragment impacts on soil erosion processes and provides insights into potential research requirements and solutions. [ABSTRACT FROM AUTHOR]

Filling mining technology is an important representative technology to realize green and low-carbon mining. The backfill materials have distinct rheological characteristics under the long-term action of formation loads and groundwater seepage. In order to study the creep characteristics of backfill materials under different moisture contents and reveal their aging-mechanical properties, based on the Riemann-Liouville fractional calculus and damage mechanics theory, the fractional element and damage variables are introduced to improve the traditional Bingham model, and the fractional Bingham creep damage model is proposed. Based on the experimental data of gangue cemented backfill under different moisture content, the parameters of the creep model are obtained by using user-defined function fitting and the least square method. The results show that the improved Bingham fractional creep damage model can describe the whole creep process of backfill materials under different moisture contents, and the rationality of the model is verified. Compared with the traditional Bingham model, the fitting degree of the Bingham fractional creep damage model is higher, which solves the problem that the traditional Bingham model cannot describe the nonlinear creep stage. Model parameter α and ξ increase with the increase of axial stress and moisture content. Under the same moisture content, η gradually increases with the increase of axial stress. This work has a certain reference significance for studying the mechanical properties and creep constitutive model of backfill materials containing water. [ABSTRACT FROM AUTHOR]

Hybrid power system which consists of a proton exchange membrane fuel cell and a battery has great perspective for Unmanned Underwater Vehicles (UUVs). As fuel cell’s working point has a direct relationship with its efficiency and lifetime, a key concern of the hybrid power system is the power distribution between the two parts. Aiming at minimizing the equivalent hydrogen cost, this work presents an optimal real-time energy management strategy based on the Pontryagin’s minimum principle. Compared with some other methods, this method possesses shorter calculation time and smaller storing space, which is helpful for online optimization in actual applications. In this research, a typical UUV working profile is tested with different initial co-state values to evaluate the proposed method, and the results indicate good robustness and effectiveness.

The diagnostic horizon in a soil is reflective of the environment in which it developed and the inherent characteristics of the material, therefore quantitative approaches to horizon delineation should focus on the diagnostic horizon. Moreover, it can enable the exchange and transfer of soil information between different taxonomic systems. This study aims to explore the use of deep learning and RGB images to train a soil diagnostic horizon identification model that can help field workers determine soil horizon information quickly, efficiently, easily, and cost-effectively. A total of 331 soil profile images of the main soil categories (five soil orders, including Primosols, Ferrosols, Argosols, Anthrosols, and Cambosols) from Hubei and Jiangxi Provinces were used. Each soil profile image was preprocessed and augmented to 10 images and then inputted into the UNet++ architecture. The mean intersection over union and pixel accuracy of the model were 71.24% and 82.66%, respectively. Results show that the model could accurately identify and delineate the soil diagnostic horizons. Moreover, the model performance varied considerably due to the definition of the horizon and whether the diagnostic conditions applied to a wide range of visual features on RGB images, the number of samples, and the soil characteristics of the study area. [ABSTRACT FROM AUTHOR]

Two-dimensional direct stability analysis and numerical simulation are used to identify and characterize the primary instability of the flow around two tandem cylinders with different diameters. The ratio of the diameter d of the upstream cylinder to the diameter D of the downstream cylinder is varied from 1.0 to 0.4, while the distance L from the center of the upstream cylinder to the front stagnation point of the downstream cylinder is varied from 1.0D to 8.0D. Three typical spacings are chosen to describe the different scenarios observed, and the results for each configuration are described in detail. Three different unstable modes are identified, and the structural sensitivity and nonlinear characteristics of each mode are investigated. The results show that when d/D = 0.6 and L / D ≥ 3.5 , the migration of the eigenvalues corresponding to the most unstable modes can be observed for a range of Reynolds numbers. This is ultimately shown to be caused by the transition of the unstable mode. At the same time, this mode transition changes the core region of the instability mechanism. Moreover, two different mechanisms that lead to vortex shedding in the gap between the two cylinders and a secondary bifurcation behavior of the flow around the downstream cylinder under a specific configuration are observed. To obtain a more comprehensive view of the first instability, a transient growth analysis of the flow is also performed, and the critical Reynolds number in each case is discussed. [ABSTRACT FROM AUTHOR]

In the in situ modified fluidized mining engineering, the surrounding rock of the shaft wall is prone to creep instability damage under the action of disturbance and seepage water pressure, which seriously affects the stability of the surrounding rock of the deep in situ modified fluidized mining. In order to study the nonlinear creep damage and fracture characteristics of deep rocks under the combined action of seepage water pressure and disturbance load, a self-developed rock perturbation creep test rig under the action of seepage water pressure was used, and shale was used as the rock sample. In the method of staged loading, the rock uniaxial compression perturbation creep test under static axial pressure, different perturbation frequencies, and different seepage water pressures was carried out, and the creep characteristics of shale under the combined action of perturbation and seepage were studied. The results show that with the increase of seepage water pressure, the creep failure time of the rock decreases, and the ultimate strain value increases; with the increase of the disturbance frequency, the creep failure mode of the rock gradually transitions from shear failure to tension failure. When water pressure and disturbance load exist at the same time, rock creep is more sensitive to seepage water pressure; based on experimental results, a shale perturbation creep damage model considering the influence of seepage water pressure and disturbance frequency is established, and the model is verified. The research results have important theoretical significance for guiding the wellbore stability control of in situ modified fluidized mining engineering. [ABSTRACT FROM AUTHOR]

Adding plant fibers such as rice husks or sisals to the mortar is one of the main methods to reuse the agricultural wastes and reduce the energy consumption of building industry. However, recent research showed some limitation of the mortar mixed with plant fibers. In this paper, sisal fibers and rice husks were added together into cement mortar to investigate its mechanical properties and the optimum mixture ratio of sisal fiber and rice husk by mix ratio test and orthogonal test. The microstructure of the sisal fiber was observed using scanning electron microscopy (SEM) to understand how the properties of the mortar were affected. Results showed that adding sisal fiber and rice husk into cement mortar significantly improved the mechanic property, anticrack performance, and impermeability of the mortar. The highest compressive strength and flexural strength can reach 17.1 MPa and 3.3 MPa. The area of early cracks was reduced by 100%, and the maximum seepage pressure was 0.36 MPa. The microstructure analysis also indicated that adding rice husk and sisal fiber have a positive effect on the mortar. These results support that adding 0.1% volume admixture of 16 mm length sisal fiber with 35% rice husk into mortar is helpful for engineering application. [ABSTRACT FROM AUTHOR]

To investigate the compressive strength and permeability of deep mudstone under stress disturbance, a triaxial rheometer is used to conduct seepage experiments on mudstone specimens with different buried depths under triaxial compression and unloading conditions. The experimental results show that the compressive strength of mudstone specimen with a depth of 1000 m is much lower than that of specimen with a depth of 200 m, and the compressive strength of mudstone increases with the increase in confining pressure. Under constant axial pressure and unloading of the confining pressure, the mudstone with a depth of 200 m exhibits brittle failure, and the strain fluctuates in a pointwise manner with the increase in axial stress. In this case, the mudstone with a depth of 1000 m exhibits a transition from brittle failure to ductile failure, and the strain fluctuates linearly with the axial stress. Further, when the volumetric strain change reaches 0.01, it shows an oblique "Z" fluctuation. During the initial stage of unloading of confining pressure, the permeabilities of both the mudstone specimens (with depths of 200 and 1000 m) decrease gradually. As the confining pressure is unloaded, the permeability of mudstone with a depth of 1000 m increases. Until the specimen is completely destroyed, the permeability of mudstone increases rapidly. Overall, this study can serve as a useful reference for analyzing the engineering disasters associated with deep rock mass, tunnel ventilation, and gas storage. [ABSTRACT FROM AUTHOR]

Purpose: Severe water erosion of coarse-textured soils, thereby exposing subsurface horizons at the surface, is a serious problem in southern China. Currently, there are few systematic studies on erosion processes and features as the various coarse-textured subsurface horizons are exposed. Materials and methods: The main objective in this study was to investigate the effects of rainfall intensity and inflow rate on the runoff, soil loss, and erosion features of three horizons of a typical soil developed from granite (topsoil horizon, illuvial horizon, and parent material horizon) in the steeply sloped region. A series of laboratory simulation tests were conducted in a 0.8-m by 3-m flume using two combined rainfall and upslope inflow condition (90 mm h−1 plus 2 L min−1 and 120 mm h−1 plus 2.66 L min−1, respectively). Results and discussion: Runoff coefficient and soil loss increased with the evolution of erosion phase from sheet erosion to rill advancement to rill maturity phase. Runoff generation increased as soil horizons with higher bulk density were exposed on the surface and as the rainfall-inflow rate increased. Additionally, rainfall-inflow rate and soil horizon had significant effects on soil loss rate, headward erosion rate, and rill density (p < 0.01). The hillslope roughness was dependent on the interaction of soil properties (clay content) and rainfall characteristics (rainfall intensity and duration). Despite the different hillslope roughness levels exhibited as result under the different rainfall-inflow treatments, the topsoil horizon always exhibited low soil loss. Moreover, as rainfall duration increased, coarse grains (quartz) were gradually enriched on the hillslope surface, which worked as "armoring" to protect the soil surface of interrill areas from further erosion, especially for the topsoil horizon. Due to the surface armoring, rill erosion was considered the main sediment source during the rill maturity phase. Conclusions: These results suggested that coarse grains could be an effective on-site soil conservation practice controlling soil erosion, which should be considered in future erosion prediction and bare land restoration in coarse-textured soils. [ABSTRACT FROM AUTHOR]

Land degradation induced by water erosion is a worldwide problem for sustainable agriculture. Erosion results in the alteration of soil properties to a varying extent that depends on soil type. However, limited attempts have been made to assess the impact of erosion‐induced land degradation on soil infiltration on a wide range of soil types. Herein, field rainfall simulation experiments were performed on prewetted bare heavy‐textured soils at three erosion degrees (no, moderate, and very severe) for five types of soils (Calcic Luvisol, Ferric Luvisol, Plinthic Alisol, Plinthic Acrisol, and Acric Ferralsol). Soil infiltration rate was determined at two rainfall intensities (45 and 90 mm hr−1) and 3‐min intervals for 60‐min runoff duration on microplots (3 m long × 0.8 m wide, 10° slope). At the low rainfall intensity, the impact of erosion‐induced land degradation on rainfall infiltration increased from Calcic Luvisol to Plinthic Acrisol, and the steady state infiltration rate (fc) was well characterized by bulk density and 1.4‐nm intergrade minerals (Adj‐R2 = 0.79, p < 0.001). At the high rainfall intensity, fc was negatively related with illite solely (Adj‐R2 = 0.25, p < .05) and generally increased with an increase of erosion severity; the impact of erosion‐induced land degradation on fc was magnified for Calcic Luvisol and Acric Ferralsol but lessened for other soil types. Collectively, the impact of erosion‐induced land degradation generally increased with increased soil structural stability at the low rainfall intensity and was determined by the interaction between soil structure and rainfall at the high rainfall intensity. [ABSTRACT FROM AUTHOR]

Abstract: Soil erosion is a serious problem world‐wide for the environment or humankind, exacerbating land degradation. However, little systematic knowledge is available about the erodibility of various types of soils at different erosional degradation levels, especially at the field scale. In this research, the spatiotemporal variations of the erodibility for 5 soil types (calcic luvisol, ferric luvisol, plinthic alisol, plinthic acrisol, and acric ferralsol) from temperate to tropical climate were investigated with field rainfall simulation experiments on prewetted bare fallow heavy‐textured soils (silty clay loam, silty clay, and clay) derived separately from loess deposits, quaternary red clays, and basalt. The experiments were performed in 3 erosion classes (noneroded, moderately eroded, and very severely eroded) and at 2 rainfall intensities (45 and 90 mm hr−1). Soil erodibility was represented by the K factor of the Revised Universal Soil Loss Equation. Soil erodibility was the lowest for the ferralsols among all the soil types and was significantly lower in the very severe than in the no or moderate erosion classes. Soil erodibility tended to be larger at the high than at the low rainfall intensity (p < .05) except for the very severely eroded luvisols, and their difference between rainfall intensities in the erodibility varied with rainfall duration. Soil erodibility could be well predicted by the combination of illite, dry aggregate stability, and amorphous aluminium oxides (adjusted R2 = .51, p < .001), and its temporal variations were significantly related with particle density, 1.4‐nm intergrade mineral, and capillary porosity (p < .05). Furthermore, soil properties selected to account for soil erodibility varied with rainfall intensity. The integrated data indicated that soil erodibility was mainly influenced by clay minerals at the region scale and soil degradation degree at the pedon scale. [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]

In the subtropical hilly areas of China, a collapsing gully, a particular type of permanent gully, poses a great threat to the productivity and sustainability of the local ecological and agricultural systems. However, few studies have been performed regarding the effects of collapsing gully erosion on soil degradation. The aim of this study was to evaluate the effects of collapsing gully erosion on soil-quality-related physical and chemical properties. The collapsing gullies that were severely affected by erosion processes were considered at three stages (initial, active and stable stages) and corresponding soil samples were collected to analyze the spatial variation of the soil physical and chemical quality at each stage. The changes in the properties were assumed to be considerable in the regions affected by the erosion process compared with those unaffected by this process. Soil physical properties were more susceptible than soil nutrients to collapsing gully erosion in different spatial locations. The soil quality index (SQI) system consists of total nitrogen (TN), total phosphorus (TP), pH, capillary porosity (CP), sand content (SA), soil cohesion (SC) and root density (RD). Collapsing gully erosion was found to affect the soil physical and chemical properties by progressively reducing the SQI. The mean SQI value was the lowest in the active stage of the collapsing gully, with a higher soil degradation. For the different spatial positions in the collapsing gullies, the scour channel showed the lowest SQI value. The limiting indicators varied in the different stages or spatial sites in the collapsing gullies. [ABSTRACT FROM AUTHOR]

Soil erosion poses a major threat to the sustainability of soil and water resources. Soil horizons differ in their properties due to pedogenic differentiation. Currently, limited research attempts have been made to assess the impact of the removal of topsoil horizons on the subsequent erosion process. The main objective in this study was to investigate the effects of erosion degree and rainfall intensity on erosion process and sediment transport mechanism. Field plot experiments were conducted on pre-wetted bare fallow Ultisols (derived from quaternary red clay) under four erosion degrees (no (E0), moderate (E1), severe (E2), and very severe (E3)) and two rainfall intensities (60 and 120 mm h −1 ). The erosion degrees were judged according to the outcrop of eluvium, illuvium (B1, B2) and parent material horizons. The simulated rainfall lasted one hour after runoff generation, and runoff and sediment were sampled at 3-min intervals to determine the runoff coefficient, sediment concentration, soil detachment rate and sediment effective size distribution. Runoff coefficient was negatively correlated with bulk density (r = −0.76, p < 0.05). Sediment concentration and soil detachment rate decreased with an increased erosion degree at the low rainfall intensity while they decreased in the order of E1 > E0 > E2 > E3 at the high rainfall intensity. Rainfall intensity and clay content played the negative and positive roles in the erosion process, respectively (Adj-R 2 > 0.80, p < 0.01). For E3, sediment transport was dominated by suspension/saltation (<0.1 mm) while for the other erosion degrees it was dominated by mechanisms of both suspension/saltation and rolling (2–0.5 mm). The average sediment size was positively correlated with silt content (r = 0.82, p < 0.05). The high variation of erosion process with erosion degree was intrinsically attributed to the difference in soil horizon nature (mainly soil texture and bulk density) and also influenced by rainfall intensity to varying extent, which should be considered in future erosion prediction. [ABSTRACT FROM AUTHOR]

The mechanism of soil structure stabilization has been rarely investigated from the perspectives of both soil material composition and porosity due to the complexity of soil structure and its formation process. Here, the relative importance of soil physicochemical properties in aggregate stability was evaluated for soils with different weathering degrees. Typical zonal soils derived from quaternary clay were collected from central to south China with increasing precipitation and temperature. Aggregate stability against slaking (MWD FW ), mechanical breakdown (MWD WS ) and swelling (MWD SW ) was determined, as well as basic properties (including clay content, soil organic matter (SOM), different forms of sesquioxides and pore size distribution (PoSD)). The degrees of soil weathering increased from central to south China with increasing free oxides content. PoSD in the eluvium (A) horizon exhibited triple and double peaks, indicating the decreasing heterogeneity of pore structures, while that in parent material (C) horizon was dominantly characterized by textural pores (< 0.05 μm). Slaking was the most disruptive mechanism in aggregate breakdown, followed by the mechanical breakdown. MWD FW decreased with soil depth. Correlation analysis showed that soil binding agents interacted significantly with pore characteristics ( P < 0.05). MWD FW and MWD WS increased with an increase in the amorphous iron oxides excluding complex form (Fe u ) content and a decrease in pH. Moreover, complex iron oxides (Fe p ) and crypto-pores (0.006–0.1 μm) enhanced the aggregate stability against slaking logarithmically and mechanical strength linearly. MWD SW was positively related with SOM ( P < 0.05). The overall results suggest that the combination of amorphous iron oxides (especially Fe u ), pH and crypto-pores play a synergetic role in the stabilization of soil structure for the highly weathered soils in subtropical and tropical areas. [ABSTRACT FROM AUTHOR]

The world has a growing need for advanced Unmanned Undersea Vehicles (UUVs) that can complete various types of missions autonomously. Power and energy systems that maximize vehicles’ range and endurance are critical to the success of these missions. The current fleet of UUVs is usually powered by lithium batteries, which have relatively low energy density and thus limit the range and endurance of UUVs. On the other hand, high energy conversion efficiency of fuel cells as well as energy-dense reactant storage may provide much longer range and endurance for UUVs. The aim of this study is to review recent progress on fuel cells and energy storage technologies for UUVs. Due to pure oxygen supply and closed-cycle operation, underwater fuel cells require adaption to existing fuel cells in terms of membrane electrode assembly (MEA), bipolar and safety measures, as evidenced by this review. For energy storage, the key issue concerned is to store fuel and oxidizer in high energy density format. From this perspective, a comparative assessment of potential fuel and oxidizer storage technologies is conducted in this study. The results indicate that aluminum fuel is the most promising candidate among hydrogen sources, whereas lithium perchlorate is the best option among oxygen sources. [ABSTRACT FROM AUTHOR]

• Aggregate microstructure along a climatic gradient was investigated by X-ray CT. • The aggregate pore size was dominated by 30–75 µm (mesopores). • SOC and Al oxides were key to aggregate pore characteristics with positive effect. Pore structure can reflect the soil aggregation process, determine various physical, chemical and biological processes in aggregates. This study investigates variations in the intra-aggregate microstructure (porosity, pore size distribution, and pore shape) of six different weathered soils across temperate (Haplic Phaeozems, HP; Haplic Luvisols, HL; Calcic Luvisols, CL), subtropical (Ferric Luvisols, FL; Plinthic Alisols, PA) and tropical (Acric Ferralsols, AF) climates. For this purpose, the three-dimensional microstructure of the soil aggregates using X-ray micro-computed tomography was quantified. Significant differences were found in the intra-aggregate microstructure of different soil types. The porosity of different effective pore diameters inside soil aggregates showed a U-shaped pattern of change, which gradually weakened with the increase in soil profile depth. HL, PA, and AF had higher total porosity and pore number, with a more uniform pore distribution, due to high content of SOC (soil organic carbon) or Fe–Al oxides. Large and long-shaped pores were found in the intra-aggregates of FL. The dominant soil intra-aggregate pores were mesopores (the porosity of effective pore size between 30 and 75 µm, P 30-75) and the soil aggregate microstructure exhibited an elongated pore morphology. SOC and Al oxides were two determinants of the intra-aggregate microstructure with a significant positive effect, whereas Fe oxides' negative effect was observed. These results have shed light on the main reasons for the differences in the microstructure of different weathered zonal soil intra-aggregates and the relationship between aggregate microstructure and cementing substances. [ABSTRACT FROM AUTHOR]

[Display omitted] • Coarse-textured soil surface morphology evolution is studied by simulated rainfall. • Surface enriched coarse grains are quantified by photography and binarization. • Soil loss in inter-rill areas is controlled by surface coarse-grain coverage. • Soil clay content and stream power is shown to fit erosion prediction. The evolution of slope surface morphology directly affects the hydrological process and forms a dynamic feedback loop with the runoff and sediment production. However, the unique erosion processes and feedback mechanism for the surface morphological changes of coarse-textured granite soils have been rarely studied previously. Here, a series of rainfall simulation experiments (intensity of 90 mm h−1) were conducted under continual intermittent rainfall conditions (duration of 20 h) on a 0.8 m by 3.0 m soil flume packed with the four coarse-textured granite soils (sieved soils from the counties of Tongcheng, Ganxian, Changting, and Wuhua, China, defined as TCA, GXA, CTA and WHA, respectively) to measure the surface roughness, coarse grain coverage, soil erosion rate, stream power and sediment sorting. The results showed: 1) the coarse grain coverage of the four soils gradually increased with rainfall duration, with the final maximum (74.89%) for CTA soil, which corresponded to the enrichment of fine particles in the sediments; 2) the mean soil erosion rate of the four soils ranged from 0.090 to 0.76 kg m−2 min−1 with the decrease of clay content from 24.19% to 13.60% in the original soils, coinciding with the surface roughness controlled by rill erosion around the coarse grains; 3) the coarse grain cover provided a protective layer to reduce further soil loss in inter-rill areas; 4) the model of soil clay content and stream power was shown to be suitable for soil erosion prediction of coarse-textured soils (R2 = 0.93). The results highlighted soil mechanical composition and coarse grain coverage on the surface as the key factors affecting the coarse-textured soil erosion. This study facilitates our understanding of the unique erosion processes and the erosion feedback mechanism of coarse-textured soils. [ABSTRACT FROM AUTHOR]

Ecosystem conservation and restoration are the primary practices for enhancing ecosystem services (ESs) and achieving sustainable development goals. However, inappropriate land use interventions and revegetation projects may lead to an imbalance between the supply and demand of ESs. This study applied the ES matrix approach and spatial panel models to quantify the supply–demand balance of ESs in the southwest karst region and to identify their spatial determinants and spillover effects. The overall patterns for landscape metrics between 1980 and 2015 remained relatively stable, while landscape fragmentation and population growth weakened the ES supply capacity but increased the demand, which caused an imbalance (i.e. the demand exceeded the supply), particularly in the surrounding areas of the urban agglomerations. Population density and individual landscape metrics were significantly associated with ES balance (p < 0.01) and were identified as the dominant spatial determinants. Additionally, the spillover effects of determinants also influenced ES balance patterns, which should be considered in integrated landscape planning and ecosystem management to coordinate collaborations from local and adjacent regions to mitigate ES imbalance. Excessive reclamation and urbanisation temporarily improved grain provision and economic profits, respectively, but caused an imbalance in ESs and threatened ecological security. Additionally, excessive conservation practices ignored economic costs and the livelihood of residents, which threatened food security and exacerbated poverty. Therefore, a balance between the contrasting targets should be maintained through the lens of ES balance to reconcile ecosystem conservation and socioeconomic development. This study provides a complete and feasible perspective to examine and optimise human interventions, with the aim of achieving win-win goals. [ABSTRACT FROM AUTHOR]