Erosion Research Articles

Study on Soil and Water Loss on Slope Surface and Slope Stability Under Rainfall Conditions

For a binary structure slope with a soil layer on the top and a rock layer on the bottom, during the rainfall process, surface runoff will cause soil and water loss on the slope surface and damage to the slope environment. When rainwater infiltrates into the slope, the pore water pressure in the soil gradually increases, the shear strength of the soil decreases, and a weak zone is formed at the soil–rock interface, which has a significant impact on the stability of the slope. Therefore, to study the soil and water loss on the slope surface and the stability of the slope under rainfall conditions, we used theoretical analysis, indoor model tests, and numerical simulations to conduct a comprehensive exploration of this issue, and the following conclusions were formed: the pore water pressure in the shallow layer is greater than that in the deep layer, and the pore water pressure at the toe of the slope is greater than that at the top of the slope; as the slope gradient increases, the time when the pore water pressure at the toe of the slope begins to respond gradually speeds up; the slope displacement first occurs at the lower part of the slope, then in the middle, and finally at the upper part; the time when the displacement at each point on the slope surface begins to respond gradually speeds up with the increase in the slope; the damage form at a small slope gradient is mainly flow sliding, and the damage process is continuous; the damage form at a large slope gradient is mainly flow sliding and overall sliding, and the damage process is continuous and sudden; when the binary structure slope fails, the sliding surface includes the internal sliding surface of the soil and the sliding surface at the soil–rock interface, but when the slope gradient is small, the relative sliding at the soil–rock interface is small, and a continuous sliding surface cannot be formed; and when the slope gradients are small (30° and 40°), the displacement decreases continuously from top to bottom, and no overall sliding surface is formed. The larger values of plastic strain mainly occur in the upper and middle parts of the slope, there is no formation of a continuous plastic strain zone, and the damage mode is flow sliding; when the slope gradients are large (50° and 60°), the displacement is the largest in the upper part, and a large displacement also occurs in the lower part, forming a sliding surface that penetrates through the soil–soil and rock–soil layers. The larger values of plastic strain occur in the upper, middle, and lower parts of the slope, a continuous plastic strain zone is formed, and the damage modes are flow sliding and overall sliding; numerical simulations were carried out on a typical actual slope, and consistent results were obtained.

Fire Reduces Soil Nitrate Retention While Increasing Soil Nitrogen Production and Loss Globally.

Elucidating the response of soil gross nitrogen (N) transformations to fires could improve our understanding of how fire affects N availability and loss. Yet, how internal soil gross N transformation rates respond to fires remains unexplored globally. Here, we investigate the general response of gross soil N transformations to fire and its consequences for N availability and loss. The results showed that fire increased gross N mineralization rate (GNM; +38%) and ammonium concentration (+47%) as a result of decreased soil C/N ratio but decreased microbial nitrate immobilization (INO3; -56%), resulting in increased nitrous oxide (N2O; +50%) and nitric oxide (+121%) emissions and N leaching (+308%). Time since fire affected soil N cycling and loss. Fire increased GNM, ammonium concentration, and N2O emission, and decreased INO3 only when time since fire was less than one year, while increased N leaching in the short (<one year) and long (>one year) terms. Thus, the consequences of fire were a short-lived increase in N availability and N2O emissions (lasting less than one year) but with persistent risks of N loss by leaching over time. Overall, fire increased the potential risks of N loss by stimulating N production and inhibiting nitrate retention.

Rainfall Erosivity Projection in South‐East Australia Using the Improved Regional Climate Simulations

ABSTRACTRainfall erosivity is one of the most dynamic factors in the soil erosion process. The increase in soil erosion caused by high rainfall erosivity, and the subsequent loss of soil nutrients, can lead to reduced food production and ecosystem services. This research program under the New South Wales (NSW) Climate Change Adaptation Strategy, assesses rainfall pattern change, rainfall erosivity and erosion risk across NSW under future climate conditions. Daily rainfall erosivity and erosion risk were modelled by Revised Soil Loss Universal Equation (RUSLE) approach and compared with that driven by observed rainfall data. Future rainfall erosivity and soil erosion risk change were investigated from daily precipitation projection of the updated NSW and Australian Regional Climate Modelling (NARCliM1.5) for two future scenarios, RCP4.5 and RCP8.5, from the historical (1986–2005) to far future (2060–2079) periods. The annual average rainfall erosivity is projected to increase about 8% under RCP 4.5 and further decrease 5% under RCP 8.5 in NSW due to the predicted temperature rises. More frequent heavy rainfall events are projected to occur during summer (December–January–February), and the rainfall from these extreme rainfall events is expected to account for 51% of the total annual rainfall in the far future. NARCliM‐derived results underestimate annual rainfall erosivity compared with observation‐derived erosivity. There are greater instability (root mean squared error [RMSE]: 803.2) and erosivity uncertainty (Bias: 16%~48%) in high rainfall zones. At a monthly scale, dry months (June–July–August) are becoming drier, while wet months (December–January–February) are becoming wetter and more erosive. 67% of NSW is predicted to experience increased rainfall erosivity under RCP4.5, whereas most of NSW will shift to drought and its consequent effects under the high‐end emission scenario (RCP 8.5). To address the dual challenges of excessive wetness in coastal and north‐east NSW and increasing aridity in Western NSW, it is necessary to develop climate change adaptation management strategies based on high‐risk areas and monthly or seasonal conditions. With the emerging launch of NARCliM2.0, we anticipate further improvements of these predictions will be achieved by more accurate models and data at higher spatial and temporal resolutions.

LATE GLACIAL AND HOLOCENE EROSIONAL DISSECTION AND FILL IN THE TEMPORAL (EPHEMERAL) STREAM VALLEY ON THE RIGHT BANK OF THE SELENGA RIVER

The structure, composition and cut and fill sequence of the Late Glacial and Holocene erosional landforms in the Kuitunka River basin on the right bank of the Selenga River were studied based on a detailed analysis and radiocarbon dating of the soil-sedimentary sequence in the Studenyi Klyuch 2 and Kovalev Pad’ sections. A correlation was carried out between seven sections in the intermittent stream valleys in the Kuitunka River basin. There are three episodes of the Late Glacial and Holocene cutting dated back to ~18–17, ~14.7–14.3, and 0.25–0 cal. kyr BP (ka BP). There are distinguished the periods of colluvial, colluvial-deluvial and aeolian-deluvial sediment deposition in the intermittent stream valleys (17.0–14.7 ka BP) and predominantly aeolian-deluvial loess-like sediment accumulation involving pedogenetic stages (14.30–0.25 ka BP). The climatic warming and humidification led to a decrease in sedimentation rate, prevalence of loessification processes in formation of loess-like deposits, and formation of organic–accumulative soil horizons of different thicknesses. The Late Glacial warming, comparable to the Bølling – Allerød Interstadial (14.3–12.9 ka BP) and the Holocene (11.7–0 ka BP), is characterized by a dynamic change in the stages of loess-like deposit accumulation and pedogenesis. The Younger Dryas cooling (12.9–11.7 ka BP) is associated with the activation of aeolian and cryogenic processes and a short phase of pedogenesis. It was revealed that the most frequent changes in sedimentary phases and soil formation occurred during the Late Glacial Interstadial and the Early (11.7–8.2 ka BP) Holocene. The Middle Holocene (8.2–4.2 ka BP) is characterized by a decrease in the rate of accumulation of intermittent-stream valley loess-like bottom deposits and a long-term (several ka) active pedogenetic process. The cross-sections of the Late Holocene (last 4.2 ka BP) draws and valley-bottom gullies exhibit the stages of pedogenesis (4.2–1.0 ka BP), activation of erosion–accumulation processes (1.00–0.25 ka), gullying, accelerated erosion, and accumulation (last 0.25 ka BP).

Hybrid model approach for hilly sub-watershed prioritization using morphometric parameters: a case study from Bakkhali river watershed in Cox’s Bazar, Bangladesh

ABSTRACT This study investigates the morphometry of the Bakkhali watershed (BW) in the hilly districts of Cox’s Bazar and Bandarban, Bangladesh, to analyze its hydrological characteristics. Morphometric parameters were utilized to prioritize sub-watersheds (SWs) through a hybrid approach combining principal component analysis (PCA) and the weighted-sum approach (WSA). Using ArcGIS Pro 2.7.0, streams, the watershed, and SWs were delineated from a 30-m resolution COP30 DEM. Preliminary priority ranks (PPR) were determined based on direct and inverse relationships of morphometric parameters to soil erodibility. Weighted compound factors (CF) were calculated from PCA results for final prioritization. The BW, a fifth-order watershed with a drainage area of 571.52 km², shows a consistent decrease in the number of streams with increasing stream order, indicating an erosional landform. The mean bifurcation ratio of 4.09 suggests a higher tendency for soil erosion. Shape factors indicate an elongated watershed with less pronounced peak flow characteristics. The analysis identified SW2 and SW3 as high-erosion zones, SW4 and SW9 as medium-erosion zones, and SW1 as a low-erosion zone. The study demonstrates the efficacy of combining geospatial and statistical tools for SW prioritization.

Assessment and mapping of water erosion by the integration of Gavrilovic's "EPM" model in the MENA region: case study of the Admer-Ezem sub-watershed, upper Oum-Rbaa basin, Morocco.

The main goal of the research is to assess soil erosion while analyzing the spatial distribution of its evolution using the EPM (erosion potential model). Situated northwest of the upper Oum-Rbaa watershed in Morocco, the Admer-Ezem watershed is part of the research area. Its climate is Mediterranean, ranging from semi-arid to subhumid bioclimate, which favors fairly scattered vegetation and poor soil. Separating the factors of complexity and interdependence in the analysis of erosion risk was made possible quickly and effectively by the Geographic Information System (GIS) integration of thematic maps of the various Gavrilovic Equation EPM factors with their databases. It also made it possible to evaluate each factor's influence and determine how much it contributed to soil loss. The priority of the various watershed regions was made possible by the use of Gavrilovic's calculations. This basin covers a total area of 197.59 km2, experiences relatively abundant rainfall (800 mm/year), and is subject to significant anthropogenic pressure. This will have an impact on the overexploitation of natural resources in general and soils in particular. Excessive use of agricultural land has led to its fragility and increased susceptibility to erosion. These natural and anthropogenic conditions have induced an intense erosive dynamic, which can be seen in its various forms (badlands, landslides, flows, concentrated active ravines…). The use of the "EPM" model for estimating soil losses approximates the severity of the erosion phenomenon. Soil loss due to water erosion according to the model used is estimated at 32.89 t/ha/year as the highest value and 0.11 t/ha/year as the lowest value. In addition, the analysis of these results made it possible, using GIS, to determine the factors that control water erosion.

Transforming Agricultural and Sulfur Waste into Fertilizer: Assessing the Short-Term Effects on Microbial Biodiversity via a Metagenomic Approach

Fungi and soil bacteria are vital for organic matter decomposition and biogeochemical cycles, but excessive synthetic fertilizer use contributes to soil degradation and loss of biodiversity. Despite this, about 97% of soil microorganisms are unculturable, making them difficult to study. Metagenomics offers a solution, enabling the direct extraction of DNA from soil to uncover microbial diversity and functions. This study utilized metagenomics to analyze the rhizosphere of two-year-old Tonda di Giffoni hazelnut saplings treated with synthetic NPK, composted olive pomace, and an innovative fertilizer derived from sulfur-based agro-industrial waste stabilized with bentonite clay. Using 16S rDNA for bacteria and ITS2 for fungi, Illumina sequencing provided insights into microbial responses to different fertilizer treatments. The results highlighted a significant increase in the abundance of beneficial microorganisms such as Thiobacillus, Pseudoxanthomonas, and Thermomyces, especially when organic materials were included. Additionally, microbial biodiversity improved with organic inputs, as shown by increased species richness (Chao1) and diversity (Bray-Curtis) greater than 20% compared with NPK and unfertilized soils (CTR). These findings emphasize the importance of organic fertilization in enhancing soil microbial health, offering a sustainable approach to improving soil quality and hazelnut productivity.

Based on AHP, The Ecological Environment of Fenhe River Basin Is Evaluated

he evaluation of the ecological quality of the Fenhe River Basin is of great significance for the high-quality development of the Yellow River Basin and Shanxi Province. In this paper, the analytic hierarchy process (AHP) is used to evaluate the ecological environment of Fenhe River Basin. Firstly, based on the relevant research literature, the ecological environment evaluation index is determined, and the influencing factors of the evaluation index are determined. Secondly, the weight of different influencing factors is determined based on AHP method, and the weight of evaluation index is obtained. Finally, the ecological environment of Fenhe River Basin in different years was analyzed by weight analysis results and expert scoring method. The results show that the ecological environment evaluation indexes of Fenhe River Basin are : water loss, soil loss, water pollution and vegetation reduction; the influencing factors of the evaluation index are : rainfall factors, soil and water conservation measures, reservoir construction, industrial water use, coal mining, engineering construction, solid waste pollution, urban development, industrial structure change, population change; from 2000 to 2020, the ecological quality of the Fenhe River Basin continued to improve, indicating that the policies and measures adopted for ecological management were effective. The ecological deterioration near the main stream and tributaries of the middle and lower reaches of the Fenhe River is related to the pollution of mine environment and industrial sewage.

Delayed environmental pollution caused by transient landscape storage - An example from the Lesser Antilles.

The strong pest pressure on intensive banana cultivation in the French West Indies led to the intensive use of chlordecone (an organochlorine insecticide) between 1972 and 1993. Due to its high toxicity for the population and the environment, many studies were conducted on the transfer of chlordecone over the last 20 years. However, most studies focused on the dissolved fraction of chlordecone, while the particle-bound fraction was understudied. Therefore, this study reconstructs pluri-decadal erosion rates (i.e. 1980-2023) and associated chlordecone particle-bound transfers from soil and sediment cores sampled in a cultivated headwater catchment (Saint-Esprit, Martinique). Based on sediment accumulation analysis in an agricultural reservoir, high erosion rates (i.e. 10 t ha-1 yr-1) were found in the investigated catchment during the study period, with values exceeding the estimated tolerable soil loss rate in tropical context (i.e. 2.2 t ha-1 yr-1). Based on the analysis of soil cores sampled along a banana plantation hillslope, this study highlights the formation of colluvial deposits with high levels of chlordecone contamination. When these areas are affected by erosion processes, this leads to massive remobilization of particle-bound chlordecone to water bodies. Indeed, in sediment sampled in the downstream reservoir, we observed a drastic increase in these transfers since 2006, synchronous with changes in agricultural practices. This study therefore highlighted the occurrence of legacy contamination at toeslope positions, which was estimated to potentially persist for 4000 to 11,000 years. Such a residence time highlights the need to implement changes in land management to effectively reduce agricultural soils erosion, particularly in areas identified as "temporary deposition zones" for chlordecone contamination, in order to protect downstream water bodies from chlordecone transfer. To achieve this, agricultural practices that may increase soil erosion, such as herbicide application or intensive ploughing, should be minimized. Overall, this study improved our understanding of erosion and associated chlordecone transfers in tropical environments.

Why do people live in disaster-prone char regions? Perspectives from Assam, India

People residing in the char regions of Assam are among the most vulnerable in the state, and particularly susceptible to multiple disasters such as floods, storms, and land erosion. Despite the existing vulnerabilities and widespread poverty, people continue to live in these areas. Our research aims to investigate why people continue to reside in these areas in such conditions and explore the feasibility of relocation as a possible solution to catastrophe risk mitigation, considering people's perceptions of living in these locations. This study uses a mixed method’s approach to achieve its objectives, based on primary data, collected through a household survey and focus group discussions. A total of 394 char residents from four districts of Assam participated in data collection. The Contingent Valuation Method (CVM) has been applied to understand residents' living preferences. Additionally, we used regression models to determine the factors influencing char residents' preference for living in these vulnerable areas. Our findings reveal that while most people prefer to live in the char areas, the risks of multiple disasters are driving some to consider leaving, exacerbated by infrastructure bottlenecks. However, char dwellers do not view relocation as a desirable solution. Alternatively, improving infrastructure and reducing disaster risks could lead to higher-levels of development and satisfaction for char residents.

Assessing the Global Sensitivity of RUSLE Factors: A Case Study of Southern Bahia, Brazil

Global sensitivity analysis (GSA) of the revised universal soil loss equation (RUSLE) factors is in its infancy but is crucial to rank the importance of each factor in terms of its non-linear impact on the soil erosion rate. Hence, the goal of this study was to perform a GSA of each factor of RUSLE for a soil erosion assessment in southern Bahia, Brazil. To meet this goal, three non-linear topographic factor (LS factor) equations alternately implemented in RUSLE, coupled with geographic information system (GIS) software and a variogram analysis of the response surfaces (VARSs), were used. The results showed that the average soil erosion rate in the Pardo River basin was 25.02 t/ha/yr. In addition, the GSA analysis showed that the slope angle which is associated with the LS factor was the most sensitive parameter, followed by the cover management factor (C factor) and the support practices factor (P factor) (CP factors), the specific catchment area (SCA), the sheet erosion (m), the erodibility factor (K factor), the rill (n), and the erosivity factor (R factor). The novelty of this work is that the values of parameters m and n of the LS factor can substantially affect this factor and, thus, the soil loss estimation.

Use of Geomatic Techniques for Mapping Suspended Solids in Aquatic Ecosystems: The Case Study of Guayas River, Ecuador

Satellite images cover large remote areas and are useful for detecting and monitoring water bodies. In Ecuador, since 1950, the lower Guayas River basin has undergone significant natural and anthropogenic changes that have impacted its dynamics and sustainability. This study aims to analyze through in situ data and geomatic techniques the change that the river has undergone in a decade by mapping the Suspended Sediment Concentration (SSC). Increasing levels of pollution in the river have raised concerns, prompting various approaches to measure and mitigate sedimentation to maintain the sustainable quality of the watershed. The spatiotemporal variations of SSC in the Guayas River revealed a remarkable variability, influenced by the operation of reservoirs, changes in land use, erosion, and sedimentation causing SSC in 2013 to range from 64.82 to 707.06 mg/l in the satellite image of 9/16/2013 and from 87.58 to 933.36 mg/l in the image of 7/26/2023. Understanding this distribution is crucial for the environmental protection and sustainability of aquatic ecosystems. This study used Landsat 8 data, an atmospheric pre-correction, and a remote sensing model. The results indicate a creasing trend of SSC in the stretches of the Guayas River between 2013 and 2023, which allows the understanding of the spatiotemporal dynamics of suspended sediment transport.

Effect of bedrock permeability on runoff and soil loss in soil-mantled karst slopes under successive rainfall conditions

Soil-mantled karst slopes exhibit rapid surface-belowground hydrological responses to rainfall because thin soil layers cover the bedrock. Bedrock features may play important roles in surface-belowground hydrological processes; however, the underlying mechanisms remain unclear. Herein, the effects of impermeable (no fissures) and permeable (3 % fissure rate) bedrock (BS1 and BS2, respectively) on the surface and belowground runoff and soil loss processes were investigated during three successive rainfall events. During each event, the surface runoff (SR), subsurface runoff (SBR), soil–rock interface flow (SRIF) and bedrock fissure permeation flow (BFPF) were recorded. The results showed that the SR and SBR rates for the BS1 slope were significantly greater than those for the BS2 slope (P < 0.05) under all rainfall events. During rainfall, the SR and SBR accounted for ∼ 19 % and 8 %-12 % of the rainwater on the BS1 slope, respectively, and both were less than 5 % of the rainwater on the BS2 slope. Approximately 40 %-55 % of the rainwater was partitioned into SRIF on BS1 slope, and 54 %-74 % of the rainwater was partitioned into the BFPF on the BS2 slope. Furthermore, the BFPF on the BS2 slope was 33 % greater than the SRIF on the BS1 slope at the 1st rainfall and it increased to 50 % at the 3rd rainfall, suggesting that the successive rainfall increased the difference in rainwater loss from the bedrock surfaces between the slopes with different permeabilities. The surface soil loss rate was very low (< 0.01 g·m2·s−1) due to the low SR, and a significant positive correlation was found between the SR rate and surface soil loss rate (P < 0.01) for both slopes. Compared with that on the BS2 slope, the soil loss on the BS1 slope was greater because of the higher SR rate. The belowground soil loss curves were discontinuous, indicating that the belowground soil loss process was very different from the surface soil loss. Therefore, bedrock permeability has a strong influence on runoff and soil loss in soil-mantled karst slopes, and this effect further increases with successive rainfall events.

Photovoltaic Soiling Loss in Europe: Geographical Distribution and Cleaning Recommendations

Despite being one of the major issues that photovoltaic systems face worldwide, estimating the energy and economic magnitude of soiling of solar collectors still represents a challenge. This work presents a first European assessment of the soiling loss and of the cost-effectiveness of soiling mitigation. New soiling maps are generated through the interpolation of reanalysis data, calibrated against ground-measured losses from sensors installed across the continent. The results show that Europe experiences an average annual soiling loss of 0.9% if rain is considered a perfect cleaning agent. However, if a cleaning effectivity by rain of 10% is assumed, this annual loss increases up to 5.3%. In some southern locations, soiling losses are markedly seasonal, while these are more consistent in central Europe. These losses can have repercussions on the economics of photovoltaics, increasing the levelized cost of electricity up to 4% or 15% depending on the cleaning effectivity of rain. The losses are also found to vary significantly in some sites from year to year, highlighting the need for continuous monitoring. The study concludes that implementing adequate soiling mitigation measures is strongly recommended in most of the regions due to the high electricity prices and the comparatively low cleaning costs.

The effect of surface flow conditions on WEPP interrill erodibilities

The Water Erosion Prediction Project erosion model (WEPP) was developed as an event-based more process-based replacement for Universal Soil Loss Equation (USLE) based models in predicting soil erosion as a guide to conserving soil in the USA. However, WEPP has not been shown to predict event soil losses for bare fallow USLE plots better than USLE-based models when stipulated input values have been used. To some extent, this problem can be attributed to the availability of more refined and site-specific input parameters for the USLE-based models. This is true with respect to WEPP’s capacity to model raindrop-driven erosion on USLE plots under natural rainfall. Stipulated values for WEPP interrill erodibilities in the USA were determined only for ridge side slopes but USLE-based models focus on the prediction of long-term average annual soil loss caused by both sheet and rill erosion on planar surfaces. The interrill erodibilities determined for ridge side slopes did not correlate well with those on adjacent flat surfaces sloping along the land slope under the same rainfall conditions. Surface flow conditions, particularly flow depth, differ between the short high gradient side slopes associated with ridges, and the lower gradient slopes in interrill and sheet erosion areas on USLE plots. Failure of WEPP to account for the influence of different flow conditions between ridged and flat areas on raindrop-driven erosion affects the veracity of WEPP to predict average annual soil loss on USLE plots under natural rainfall and the use of WEPP to act as a replacement for USLE based models as an aid to make land management decisions to conserver soil in the USA.

Evolution of mechanical behavior in granular soil during fine particle loss simulated by salt dissolution: Insights from ring shear tests

Fine particle loss in soil is one of the main causes of slope instability and geotechnical structure failure. Loss of fines can cause instability in granular assembles by changing the fabric and microstructure of the sample. However, real-time monitoring of the evolution of mechanical behavior in granular soils during the particle loss process is still poorly explored. This study presents a novel approach by simulating fine particle loss through salt dissolution in ring-shear tests, offering real-time insights into the mechanical evolution of granular soils under realistic stress conditions. Meanwhile, the shear resistance, shear displacement, vertical displacement, salt content, and acoustic emissions were simultaneously recorded. The test results showed that the instability of the sample was triggered by the loss of fine particles. With a gradual loss of fine particles, both the vertical and shear deformations and the void ratio increased. The evolution of shear resistance in the sample can be divided into three stages: stress weakening, then strengthening, and finally recovery to the initial value. We infer that the evolution of shear resistance originated from the collapse and rearrangement of its granular fabric and microstructure. Additional evidence for this hypothesis was provided by high-frequency acoustic emissions (approximately 150 kHz), suggesting buckling of the force chains accompanying the particle loss process. Furthermore, the sample experienced greater shear deformations and stress weakening that developed under a larger initial fine content or a higher normal stress. This finding may provide valuable insights into the mechanical behavior of granular soil during the fine particle loss process.

Evaluation of adaptive capacity of slope regulation and storage measures on the Loess Plateau under drought stress

The study evaluated the adaptive ability of slope regulation and storage measures (SRASM) under drought stress, providing scientific basis for improving water resource management and ecological protection in the arid environment of the Loess Plateau region. Four SRASM including afforestation on the hilltop (forestland engineering), returning farmland to forest on the hillside (grassland engineering), building terraces on the hillside (terraced fields engineering) and damming and silting on the valley floor (silting dam engineering) can effectively solve the problem of water and soil loss on the Loess Plateau. However, it is still unclear how the adaptive capacity (resistance and resilience) of these SRASM under drought stress. This study took the above four SRASM as the study object, used the performance of the four SRASM after drought and rehydration events as the basis for judging the adaptive capacity under drought stress. It proposed evaluation methods for drought and rehydration events, as well as calculation methods for resistance and resilience. Furthermore, it analyzed the adaptive capacity of different SRASM and different sub-basins in the middle reaches of the Yellow River under drought stress, as well as the impact of slope on adaptive capacity. The results showed that when light and moderate drought occurred, four SRASM recovered to their normal state after rehydration. In terms of resilience, forestland engineering > grassland engineering > terraced fields engineering > silting dam engineering, and grassland engineering had the most prominent ability to resist drought. As the slope increased, the adaptive capacity decreased. From a spatial perspective, the resilience in the western part of the middle reaches of the Yellow River was lower than that in the eastern, and the spatial distribution of resistance in the middle reaches of the Yellow River generally decreased from northwest to southeast.

Biobased hydrophobic liquid mulch film from soybean oil and starch for enhanced terraced field cultivation.

Terraced agriculture faces soil loss during rainstorms leading to natural disasters and crop growth impediments. This study describes a novel biobased hydrophobic liquid mulch film comprised of waste soybean oil, starch, and acrylate monomers that can be used to enhance terraced field cultivation. The novel film, optimized at a 3:7 soybean oil to acrylate monomers ratio, exhibited superior spray ability, reduced wicking, and excellent film formation, which are crucial for its effectiveness as a water erosion barrier. The wet state of the SOSA film demonstrated optimal impact resistance, with increased elongation at break and reduced breaking strength compared to its dry state, facilitating seedling emergence. It significantly improved soil moisture retention (4.8-5.7 %) and temperature (0.9-5.6 °C) and boosted maize seed germination by 28 %. Under extreme conditions of a 24° slope and 90 mm/h rainfall, the SOSA film achieved an 80.6 % reduction in soil loss and a 57.4 % increase in pakchoi yield over bare soil. This study's comprehensive analyses confirmed the film's formation mechanism and provided a scientific basis for its practical application performance, highlighting the film's unprecedented success in using waste materials for sustainable terrace farming and its potential as a transformative approach to soil conservation and crop productivity.

Mitigating rainfall induced soil erosion through bio-approach: From laboratory test to field trail

Extreme rainfall events exacerbated by global warming can pose great threats to soil stability, causing severe soil erosion and triggering various disasters, such as landslide, debris flow, and land degradation. This study explores the efficacy and critical influence factors of a bio-approach utilizing microbially induced calcite precipitation (MICP) for soil erosion control by conducting a series of laboratory tests. The field trial was also performed to explore the long-term effectiveness of MICP treatment on soil slope under natural rainfall. The laboratory tests results indicate that the peak penetration strength increased 4.43 times, and the soil slaking index and soil loss during rainfall decreased by up to 65.7 % and 92.6 % after MICP treatment. The optimal concentration of cementation solution was found to be 1.0 M. Both the one-phase and two-phase MICP methods proved effective in enhancing soil erosion resistance. However, the two-phase MICP method demonstrated a more pronounced impact on surface soil improvement, while the one-phase MICP method achieved a more uniform treatment effect. The 11-months field erosion trials validated the remarkbale durability of MICP treatment in controlling soil erosion. Additionally, more cycles of MICP treatment further enhanced the soil erosion resistance to rainfall. The bonding and filling effect of MICP-produced CaCO3 precipitates played a crucial role in the improvement of soil water stability and mechnical strength, thereby significantly mitigating soil erosion caused by raindrop and surface runoff during natural rainfall. This study provides valuable suggestions for the pratical application of MICP approch on soil erosion control against increasing extreme rainfall, which is also expected to offer a controllable and sustainable soil improvement solution under the climate change.

Morphological changes of river Bank Erosion and channel shifting assessment on Arial Khan River of Bangladesh using Landsat satellite time series images

The continuous processes of erosion and deposition in rivers are intricately linked to changes in land use and land cover (LULC), reflecting dynamic landscape transformations. This study investigates the rate of riverbank erosion, channel shifting, and the impact of erosion on LULC dynamics along the Arial Khan River. Utilizing GIS and remote sensing techniques, we analyzed time-series satellite images from 1993 to 2024 within a 2 km buffer zone of the floodplain. Supervised classification methods were applied for LULC analysis, with results validated using confusion matrices to assess classification accuracy. ArcGIS 10.8 was employed to analyze channel centerline migration, while NDVI analysis assessed vegetation health. The study reveals that between 1993 and 2024, 5142.60 ha were lost to erosion, while deposition affected 4756.52 ha, with erosion surpassing deposition overall. The river shifted an average of 0.66 km during this period, with higher migration rates in Muladi Upazila compared to Babuganj Upazila. Settlement areas expanded significantly from 137.82 ha in 1993 to 2768.68 ha in 2024, while agricultural land declined substantially. These findings provide valuable insights for policymakers to address erosion severity in confluence zones and lay the groundwork for sustainable land management practices.