High Erosion Research Articles

Tailoring microstructural features of Cr3C2-25NiCr coatings through diverse spray variants and understanding the high-temperature erosion behavior

Thermal sprayed Cr3C2-NiCr coatings are widely used to protect industrial components from ambient or elevated erosive degradation. Various thermal spraying techniques such as plasma spray, detonation spray (DS), high velocity oxy-fuel (HVOF) and high velocity air-fuel spray (HVAF) are widely used to deposit Cr3C2-NiCr coatings. The choice of thermal spraying technique governs the inflight particle velocity and temperature, resulting in unique coating microstructural features, characteristics and erosion performance. In this study, Cr3C2-NiCr coatings are deposited through HVAF, DS and axial plasma spray. A comprehensive comparative analysis was performed to understand the process-structure-property relationship of Cr3C2-NiCr coatings, which correlated with the room and high temperature erosion performance. HVAF spray deposited Cr3C2-NiCr coatings with preferred microstructural features and properties, ensuring superior (high/room temperature) erosive resistance. Cr3C2-NiCr coatings deposited via DS spray performed second best, while plasma sprayed exhibited defective microstructure with inferior mechanical properties, resulting in substandard erosion performance.

The evolution of the Maya coastal landscape in the Mexican Caribbean during the last 6200 years

The modern configuration of tropical coastlines is a result of changes in sea level and regional hydroclimates during the Holocene. In some regions, such as the Yucatan Peninsula, human occupation has also played an important role in defining coastal dynamics. We use a multiproxy analysis of a 6200-year-long sedimentary record from La Encantada lagoon, located near the Bay of Chetumal, Mexican Caribbean, to reconstruct local and regional environmental dynamics. By characterizing the record in terms of pollen and charcoal content, and geochemical composition, we aim to determine the relative importance of sea level rise, long term trends of moisture availability, and anthropic influences in the evolution of the Mayan coastal landscape. Our findings indicate a dominance of marine influences between ∼6200 and 5000 cal yr. BP, probably resulting from the rapidly rising sea level. During this time, whereas the water column was brackish, fluvial dynamics seem characterized by high erosion and the development of riparian mangroves. The geochemical record indicates a millennial-scale trend towards drier conditions, likely associated with the southward migration of the Intertropical Convergence Zone through the Holocene. This trend is also reflected in a progressive increase in the abundance of deciduous taxa in the vegetation. Centennial-scale climatic dynamics, on the other hand, seem associated with variability of the North Atlantic Subtropical High. Anthropogenic influence is evident around ∼5000 cal yr. BP, when local fires became more frequent and riparian mangroves were depleted. Taxa associated with human influence substantially increased at ∼3600 cal yr. BP, coinciding with an erosion increase indicated by the geochemical record. At ∼2200 cal yr. BP, anthropic disturbance indicators decrease, suggesting a potential role of modified agricultural practices to control soil erosion. The last ∼1000 years have been characterized by a decline of agricultural activity and a recovery of the riparian mangroves, suggesting modern vegetation is a result of forest recovery during the last millennium. Overall, our results show that sea level rise and changes in the regional hydroclimate modulate the evolution of the regional landscape, particularly through influences on the sedimentation rates. However, human occupation represents an overpowering influence that can modulate processes associated with natural forcings.

Google earth engine based assessment of soil loss using the RUSLE Model: A study of Cauvery Delta Zone, Tamil Nadu, India

Tamil Nadu is very susceptible to soil erosion due to its deforestation, urbanization, complicated terrain and heavy rainfall. The objective of this study was to estimate soil erosion in the Cauvery-delta zone (CDZ) of Tamil Nadu, India, using the Revised Universal Soil Loss Equation (RUSLE) model in Google Earth Engine (GEE) platform. The GEE environment provides a faster and better method for spatial output maps. Several parameters including runoff-rainfall erosivity factor (R), soil erodability factor (K), topographic factor (LS), cropping management factor (C), and support practice factor (P) takes into consideration for RUSLE model. The result revealed that the annual average soil loss within the Cauvery delta zone is approximately 49.08 t/hac/year (metric tonne per hectare per year). The study area has a 45 % very high erosion risk, 42.6 % severe erosion risk, and 8.4 % high risk. Other erosion risk classes, such as slight and moderate erosion, accounted for 3 % and 1 % of the total area, respectively. The results of the study indicate that GEE allow targeted solution to reduce future soil erosion.

Google earth engine based assessment of soil loss using the RUSLE Model: A study of Cauvery Delta Zone, Tamil Nadu, India

Tamil Nadu is very susceptible to soil erosion due to its deforestation, urbanization, complicated terrain and heavy rainfall. The objective of this study was to estimate soil erosion in the Cauvery-delta zone (CDZ) of Tamil Nadu, India, using the Revised Universal Soil Loss Equation (RUSLE) model in Google Earth Engine (GEE) platform. The GEE environment provides a faster and better method for spatial output maps. Several parameters including runoff-rainfall erosivity factor (R), soil erodability factor (K), topographic factor (LS), cropping management factor (C), and support practice factor (P) takes into consideration for RUSLE model. The result revealed that the annual average soil loss within the Cauvery delta zone is approximately 49.08 t/hac/year (metric tonne per hectare per year). The study area has a 45 % very high erosion risk, 42.6 % severe erosion risk, and 8.4 % high risk. Other erosion risk classes, such as slight and moderate erosion, accounted for 3 % and 1 % of the total area, respectively. The results of the study indicate that GEE allow targeted solution to reduce future soil erosion.

Identification of priority areas for soil erosion control based on minimum administrative units and karst landforms in karst areas of Guizhou

Soil erosion is one of the most serious ecological threats in karst areas of Southwest China. The identification of priority areas for remediation and its driving factors is essential to improving the efficiency of prevention and control. The present study systematically considered natural and socio-economic factors not involved in the revised universal soil loss equation (RUSLE) model, and determined priority areas for soil erosion management based on minimum administrative units and karst landforms. Then, the driving factors were identified by using geographic detector. The results showed that the priority areas were mainly concentrated in the southwest, southeast and northeast, overlapping with the severely eroded areas (Erosion rate=45.79 t·ha−1·a−1). Gradient risk zones had geomorphological differences, but the most eroded zones were all controlled by bedrock exposure rates, elevation, or slope position. The spatial correlation and high erosion rate of priority areas provided opportunities to optimize the efficiency and cost of control. Driving factors were affected by karst landforms. The explanation power of slope position on soil erosion was higher in the peak cluster depressions and karst basins with small undulations ([Formula: see text]), while the karst gorges, trough valleys and plateaus with large undulations gradually decreased ([Formula: see text]). The interaction of driving factors will enhance the explanatory power for soil erosion. Among them, the repetition rate of elevation was 60%, and the repetition rate of lithology and development index was 40%. This study provides useful information for identifying and managing priority areas for soil erosion control, and enriches the theory of soil and water conservation in karst areas.

Numerical assessment of cavitation erosion risk on the Delft twisted hydrofoil using a hybrid Eulerian-Lagrangian strategy

Cavitation damage is a major threat to the life span of fluid machinery and has been a hot research issue in engineering for a long time. The current work aims to show the ability to assess cavitation erosion risk on the twisted hydrofoil using a hybrid Eulerian-Lagrangian solver. The volume of fluid method is used for the liquid-vapor interface of resolved vapor structures, while the discrete bubble model is utilized to track micro-scale unresolvable bubbles. A two-way coupling approach is introduced to enable the transition between resolved cavities and bubbles based on their volume, relative location, and shape. A Lagrangian erosion model considering the effect of asymmetric bubble collapse is proposed to predict cavitation erosion risk. Compared with the experimental result, the current model can accurately identify the high erosion risk regions on the hydrofoil surface. The distribution and intensity of the high impact pressures emitted from bubbles is quantitatively evaluated. In addition, the erosion sensitive zones at different stages of the one cloud cavitation cycle are determined and the hydrodynamic mechanisms of aggressive collapse events are analyzed in detail. The results reveal that the potential erosion risk is highest in areas where primary shedding occurs, which causes the macroscopic cavity to roll up. Bubbles with high impact pressures are mainly focused around the edges of the shedding cavity. The secondary shedding contributes to erosive structure in a limited middle angle of attack area, such that when the primary shedding U-shaped structure evolves and begins to collapse, it becomes less erosive, and only isolated points of erosion is found. Further investigation demonstrates that this is due to a transformation from U-shaped vortex to O-shaped vortex, moving the bubbles gradually away from the hydrofoil surface, thereby reducing the cavitation erosion risk.

Modelling Water Erosion and Mass Movements (Wet) by Using GIS-Based Multi-Hazard Susceptibility Assessment Approaches: A Case Study—Kratovska Reka Catchment (North Macedonia)

Kratovska Reka is a short (17.3 km) left tributary of Kriva Reka, whose watershed (68.5 km2) is located on the northwestern slopes of the Osogovo Mountains (North Macedonia). Due to the favorable natural conditions and anthropogenic factors, the Kratovska Reka catchment is under a high risk of natural hazards, especially water erosion and landslide occurrences. For this reason, the paper presents an approach of modelling of potential erosion and areas susceptible to the above-mentioned hydro-meteorological hazards in the Kratovska River catchment. Firstly, this study analyzed the main geographical features that contribute to intensive erosion processes in the area. Then, using the Gavrilović EPM erosion potential method, an average value of 0.56 was obtained for the erosion coefficient Z, indicating areas prone to high erosion risk. Furthermore, by using landslide susceptibility analysis (LSA), terrains susceptible to landslides were identified. The results shows that 1/3 of the catchment is very susceptible to mass movements in wet conditions (landslides). According to the combined multi-hazard model, 3.13% of the total area of the Kratovska River catchment is both at high risk of landslides and under severe erosion. The Kratovska River catchment is significantly endangered by the excessive water erosion processes (39.86%), especially on the steep valley sides, i.e., terrains that are completely exposed, under sparse vegetation, and open to the effects of distribution/concentration of the rainfall amounts throughout the year. Identifying locations with the highest erosion risk serves as the initial step in defining and implementing appropriate mitigation measures across local and regional scales, thus enhancing overall resilience to environmental challenges.

Spatiotemporal Variation in the Coupling Relationship between Human Activities and Soil Erosion—A Case Study in the Weihe River Basin

Studying the relationship between human activities and soil erosion on a regional scale is of great significance for macro-decision-making in soil erosion prevention and control. The entropy weight method and RUSLE model are used to analyze the spatiotemporal variation in human activity intensity (HAI) and soil erosion in the Weihe River Basin (WRB) from 2005 to 2020. Through geographic detectors and a four-quadrant model, the impact of various driving factors and the coupling degree of the human–land relationship are studied. The results showed: (1) During the past 15 years, the moderate, high, strong, and severe erosion areas in the WRB decreased by 9.88%, 35.89%, 45.17%, and 70.05%, respectively. The ratio of the historical sand transport modulus to the RUSLE model result is 0.83, indicating that the results obtained by the RUSLE model can be used for further analysis. (2) Slight and weak degrees account for 80% in the northwest region. The high and strong regions are mainly distributed in the Shaanxi section, accounting for 3% of the total basin. (3) The coupling between human activities and soil erosion is constantly strengthening, and the joint effect of pop and crop is the main reason for the slowdown and spatial differences in soil erosion. This indicates that the ecological environment became stable. These findings contribute by acting as references for soil and water conservation and management in the WRB to promote a harmonious relationship between humans and the environment.

PALEOLITHIC SITE SUKHAYA MECHETKA (VOLGOGRAD) IN THE CONTEXT OF STRATIGRAPHY AND PALEOGEOGRAPHY OF THE LOWER VOLGA RIVER AREA

The Sukhaya Mechetka is the most important Middle Paleolithic site in the Eastern Europe. The paper presents the analysis of the section, including its cultural layer, in the context of stratigraphy and paleogeography of the Lower Volga River region. The structure of the section represents 11 main stages of sedimentation and paleogeographic evolution of the site territory, which are closely related to global and regional changes in the climate and the level of the Caspian Sea. The base of the section reflects the stage of a river existence on the territory of the site that flowed into the Volga River estuary, formed by the Early Khazarian transgression of the Caspian Sea at the end of the Middle Pleistocene (MIS 6). A long continental period of evolution under multi-directional climate fluctuations of different amplitudes from the Mikulino interglacial (MIS 5e) till the Late Valdai glacial epoch (MIS 2) is reflected in the middle part of the section. The Late Khazarian and Hyrcanian transgressive basins (MIS 5), as well as the Paleo-Khvalynian stage (MIS 3) of the Caspian Sea did not reach the latitude of Sukhaya Mechetka. The stage of Early Khvalynian transgression (MIS 2, 16 190 ± 200 years ago) during the degradation of Ostashkovo glaciation is expressed in the upper part of the section. Three paleosoils have been found that reflect the warming periods of the MIS 5 stage and are related to its 5e, 5c and 5a sub-stages. The middle paleosoil contains a cultural layer assigned to the Micoquian/KMG community of Northern Eurasia. The climate was moderately warm during the Neanderthal settlement of the territory, steppe landscapes dominated the interfluve, and the forests grew in the balka. The Hyrcanian transgression of the Caspian Sea with an estuary in the Volga River valley predetermined a high erosion basis and the formation of a balka with a wide bottom and gentle banks. A permanent fresh watercourse attracted mammals which were an object of hunting for ancient men. All this, obviously, became a basis for the organization of settlement in the Sukhaya Mechetka balka. Correlation of the section with detailed studied loess-soil sections of the Lower Volga River region makes it possible to determine the age of its cultural horizon in between 97-110 thousand years ago.

Linear Macropore Installation to Reduce Red-Soil Erosion in Sugarcane Fields

This study determines the cause of soil erosion in red soils in sugarcane fields, especially even with the use of subsoiling fissures, and to compare the effectiveness of a novel artificial linear-macropore with the insertion of fibrous material into the fractures. Four column treatments (tillage, subsoiling, linear-macropore with plant residue fillings, and no-tillage-with-mulching) were established. A subsoiler was used to break up hard soil layers to enhance infiltration, whereas mulching reduced the impact of raindrops on the soil. Sugarcane residue was inserted in the empty fissure to reinforce the structure, making linear macropore. Simulated rainfall with 20 mmh−1 was applied to the soil surface for 6 h per day for two days. Surface runoff, soil erosion, and drainage were measured during each run. Erosion was minimal (1/7 reduction), and bottom drainage was observed in the linear-macropore and no-tillage-with-mulching plots. Conversely, due to the formation of an impermeable layer or surface crust, high erosion (0.282 t-C ha−1 yr−1) and decreased drainage levels were detected in the subsoiling and tillage plots. Moreover, the aboveground protrusion of fibrous material at the linear-macropore maintained infiltration, even following crust formation. Field application of these four management strategies revealed the effectiveness of linear-macropore and mulching in reducing surface flow. Linear-macropore application maintains appropriate levels of infiltration, and insertion of plant residue fillings reinforces the macropore structure while also avoiding clogging. Hence, the linear-macropore scheme may represent an effective strategy for reducing surface runoff and red soil erosion.

Mitigasi Longsor Dengan Penataan dan Peningkatan Kemampuan Kawasan Perbukitan Pada by Pass BIL-MANDALIKA Sebagai Infrastruktur Penunjang Kawasan Ekonomi Khusus (KEK) Mandalika Lombok

One of the tourist destinations in Lombok, West Nusa Tenggara is the Special Economic Zone Mandalika (KEK Mandalika), a coastal tourism area with various supporting infrastructures on an international scale covering an area of 1,035.67 hectares. The pace of development brings environmental impacts, especially the morphology of the land in the form of mountains and hills is exposed by the conversion of land functions from proteced forest to agricultural areas without the application of land conservation methods. Bypass BIL-KEK Mandalika as the main connecting road for this tourism area is 17.2 km long flanked by hills with a slope of >30o and almost all hilly areas have been converted into agricultural areas. In this area there is minimal standing vegetation accompanied by unstable physical conditions, making all hilly areas on the BIL-KEK Madalika bypass classified as a Very High Erosion Hazard Level which reaches > 560 tons/ha/year which triggers more potential hazards. big like landslides and floods. Various steps have been taken, such as: 1) Integration of porang (Amorphopallus) and standing vegetation (canopy) applied in hilly areas in the Bypass BIL-KEK Mandalika area; 2) Emphasizing and preventing the conversion of buffer zones; 3) Rehabilitation of the Bypass BIL-KEK Mandalika Hills Area.

Modelling and mapping of soil erosion risk based on GIS and PAP/RAC guidelines in the watershed of Tassaoute (Central High-Atlas, Morocco)

Morocco watersheds, which provided many ecosystem services necessary for the socio-economic life of rural communities, are experiencing significant change and environmental problems. Therefore, examining potential soil erosion considered a major problem in the Moroccan highlands is very important to prioritize high erosion severity areas. Keeping in view of the above aspects, the present study aimed to evaluate and map areas at risk of water erosion in the upstream Tassaoute watershed (central High Atlas, Morocco), using the Priority Action Program/Regional Activity Center (PAP/RAC) method associated with Geographic Information Systems (GIS) and remote sensing. The PAP/RAC approach consisted of integrating the natural factors that influence water erosion, namely slope, lithology, vegetation cover and land use. This method provided an accurate cartographic product that reflects the reality of the state of soil degradation and the qualitative assessment of erosion. The generated erosion risk map of the study area showed that the phenomenon of erosion threatens this basin, especially in the middle and downstream, such that 40% of the basin surface has significant erosion and the high and very high degree of erosion represented 27% of the total surface of the study area. These results therefore demonstrated the PAP/CAR model reliability in assessing and mapping of water erosion risks in the upstream Tassaoute basin.

Assessment of the Impact of Climate Change on Streamflow and Sediment in the Nagavali and Vamsadhara Watersheds in India

Climate-induced changes in precipitation and temperature can have a profound impact on watershed hydrological regimes, ultimately affecting agricultural yields and the quantity and quality of surface water systems. In India, the majority of the watersheds are facing water quality and quantity issues due to changes in the precipitation and temperature, which requires assessment and adaptive measures. This study seeks to evaluate the effects of climate change on the water quality and quantity at a regional scale in the Nagavali and Vamsadhara watersheds of eastern India. The impact rainfall variations in the study watersheds were modeled using the Soil and Water Assessment Tool (SWAT) with bias-corrected, statistically downscaled models from Coupled Model Intercomparison Project-6 (CMIP-6) data for historical (1975–2014), near future (2022–2060), and far future (2061–2100) timeframes using three Shared Socioeconomic Pathways (SSP) scenarios. The range of projected changes in percentage of mean annual precipitation and mean temperature varies from 0 to 41.7% and 0.7 °C to 2.7 °C in the future climate, which indicates a warmer and wetter climate in the Nagavali and Vamsadhara watersheds. Under SSP245, the average monthly changes in precipitation range from a decrease of 4.6% to an increase of 25.5%, while the corresponding changes in streamflow and sediment yield range from −11.2% to 41.2% and −15.6% to 44.9%, respectively. Similarly, under SSP370, the average monthly change in precipitation ranges from −3.6% to 36.4%, while the corresponding changes in streamflow and sediment yield range from −21.53% to 77.71% and −28.6% to 129.8%. Under SSP585, the average monthly change in precipitation ranges from −2.5% to 60.5%, while the corresponding changes in streamflow and sediment yield range from −15.8% to 134.4% and −21% to 166.5%. In the Nagavali and Vamsadhara watersheds, historical simulations indicate that 2438 and 5120 sq. km of basin areas, respectively, were subjected to high soil erosion. In contrast, under the far future Cold-Wet SSP585 scenario, 7468 and 9426 sq. km of basin areas in the Nagavali and Vamsadhara watersheds, respectively, are projected to experience high soil erosion. These results indicate that increased rainfall in the future (compared to the present) will lead to higher streamflow and sediment yield in both watersheds. This could have negative impacts on soil properties, agricultural lands, and reservoir capacity. Therefore, it is important to implement soil and water management practices in these river basins to reduce sediment loadings and mitigate these negative impacts.

Contribution and behavioral assessment of physical and anthropogenic factors for soil erosion using integrated deep learning and game theory

Ensuring sustainable management of soil erosion is of utmost importance to prevent its adverse effects. Unfortunately, this issue has received limited attention in the past, therefore, a comprehensive study was undertaken to identify key indicators for soil erosion and develop an Ensemble Deep Neural Network (EDNN) model for predicting soil erosion probability (SEP) zones in the Guwahati urban watershed. To conduct this study, Revised Universal Soil Loss Equation (RUSLE) was employed to estimate potential soil loss (PSL). The study identified 17 physical and landscape parameters as priority factors for soil erosion initiation based on the PSL. These priority variables were analyzed using three hyper-tuned models i.e., Gradient Boosting Machine (GBM), Random Forest (RF), and Deep Neural Network (DNN) within the H2O framework. Furthermore, the study developed EDNN and hyper-tuned DNN models to predict SEP and analyzed the behavior of priority variables in high and low soil erosion probability zones using DNN-based game theory. The findings indicated that the study area experiences soil loss ranging from 140 to 181 tonnes/ha/year. Rainfall, Ff, Dd, slope, and elevation identified as the most critical factors influencing soil erosion. The EDNN model successfully predicted very high and high SEP zones, covering 172.13 km2 and 22.60 km2 respectively. Further, the result shows that high values of drainage density, cohesion, TWI, LULC, and rainfall contribute to significant soil erosion, while low values of slope, SHDI, ED, and Ff act as preventive factors. The study offers valuable insights into the construction of an EDNN model and the integration of deep learning with game theory for robust and scientific soil erosion modeling. The analysis of behavior of the priority parameters provides a novel approach for understanding the impact of individual parameter samples on soil erosion, facilitating the development of effective prevention strategies.

LULC dynamics and application of nature based solution in high erosion prone areas of Malappuram District

Kerala State is highly vulnerable to natural disasters, mainly soil erosion due to changing climatic dynamics in the steep slope. In 2018 and 2019 flood, some districts in Kerala State were affected by significant floods due to extreme and prolonged rainfall, leads to large and small landslides. Malappuram is one of the districts that got affected in 2018 and 2019 flood. Disaster risks are augmented by a critical factor that has been silently rising in the State now, which is change in the land use pattern and practices. Hence, the Land Use and Land Cover Dynamics study was conducted in the selected watersheds (Kakkarathode – Pulikkal and Palathingal) of Malappuram district, and spotted major landslides in the area. The LULC dynamics were carried out in the different time periods like 2013, 2018 and 2020. LISS IV (5.8 m resolution) satellite images were used for the analysis and field visit, to identify the related changes. Accuracy of the classification was evaluated using error matrices and kappa statistics. The overall accuracies for 2013, 2018 and 2020 were 84.93%, 86.21% and 87.5% respectively and the corresponding Kappa values were 0.82, 0.84 and 0.85 which indicates the high accuracy of the classification. The flood has mainly affected Plantation, Paddy and Mixed Plantation which had been decreased during 2018-20 and has resulted in the emergence of more Barren land and Waste Land. LULC helps in identifying the changes in the erosion prone areas. Moreover, erosion hazardous area and its prioritization in applying the soil management and conservation practices can be effectively done using LULC change assessment. Nature based solutions such as planting trees and grasses (like shrubs, vetiver grass etc.), construction of ponds, creation of green walls and assemblage of vegetations can be adopted in the region of high-risk hazardous area depending on the categorized zone.

Water Erosion Risk Assessment for Conservation Planning in the East Hararghe Zone, Ethiopia

Water erosion is accelerating soil loss rates in the East Hararghe Zone due to inappropriate human activities and their complex and intertwined interactions with natural factors, particularly in sensitive agroecosystems that lack soil and water conservation (SWC) measures. Although these dynamic processes cause prolonged impacts, a comprehensive assessment of the risk of soil erosion has not yet been undertaken at the zonal level. To bridge this gap, we employed the revised universal soil loss equation (RUSLE) prediction model, along with remote sensing and geographic information systems (GIS), to estimate annual soil erosion rates, analyze the temporal-spatial patterns of erosion risk, and evaluate the potential of standard conservation practices to reduce soil loss in croplands. Total soil erosion (in millions of tonnes/year; Mt yr−1) was estimated to be 9 in 1990, 14 in 2000, 12 in 2010, and 11 in 2020, with average rates of 33, 50, 44, and 39 t ha−1 yr−1, respectively. This suggests an overall 18% increase in soil erosion from 1990 to 2020. Over 75% of the area showed a tolerable soil loss rate (<10 t ha−1 yr−1) and low susceptibility to erosion risk. A mountainous landscape in the northwest presents extremely high erosion (>120 t ha−1 yr−1), which accounts for more than 80% of soil loss, making SWC planning a priority. Analysis of land-use land-cover change (LULCC) confirmed a higher increase in soil loss for LULCC that involved conversion to croplands, with average rates of 36.4 t ha−1 yr−1 (1990–2000), 70 t ha−1 yr−1 (2000–2010), and 36 t ha−1 yr−1 (2010–2020). The results have further revealed that implementing supportive practices such as terracing, stripping, and contouring could reduce average soil erosion by approximately 87%, 65%, and 29%, respectively, compared to the baseline model’s prediction. Therefore, a rigorous cost–benefit analysis is essential to design and implement optimal location-specific practices that maximize investment returns in SWC efforts and ecological restoration. However, we acknowledge the limitations of this study, associated with an empirical model that does not account for all forms of erosion, as well as reliance mainly on secondary data, which may affect the accuracy of the predicted outcomes.

Sustainable assessment and carbon footprint analysis of polysaccharide biopolymer-amended soft soil as an alternate material to canal lining

Kuttanad region in Kerala, India, is a place that predominantly consists of soft soil formations with low shear strength and low water resistance rendering them problematic for construction purposes. Pavements constructed on such soft deposits have been subjected to structural rutting and the high erodibility of the in-situ soil necessitates the need to use suitable ground improvement techniques. The present environmental scenario demands the implementation of sustainable techniques for ground rejuvenation and effective stabilizers for enhancing engineering properties. This study investigates the amelioration of Kuttanad soft soil using chitosan as a soil amendment to improve its durability and erodibility characteristics. The untreated and chitosan-treated samples were exposed to 5 h of wetting cycle followed by 43 h of drying cycles until their failure. The unconfined compressive strength (UCS) of samples prepared with different dosages (0.5, 2, 4%) and cured for 14, 28, 60, and 90 days was evaluated at the onset and after each drying cycle to measure their durability index. Kuttanad soil was amended with 2% and cured for 90 days withstood five cycles with a UCS of more than 1,000 kPa. The drip erosion tests were used to check the erodibility performance for the aforementioned different dosages and curing periods. The 2% and 4% chitosan amended samples resisted the entire test duration of 10 min indicating the highest water erosion resistance. The findings of the current study evaluated through durability and erosion tests reinforced the effectiveness of chitosan as an effective biopolymer for soft soils subjected to constant water attack and can be easily implemented in places with such vulnerability. A typical earthen canal lining amended with chitosan reduced the carbon emissions by 8.74 and 7.44 times compared to conventional amendments like lime and cement in Carbon Footprint Analysis.

Does helimulching after severe wildfire affect soil fungal diversity and community composition in a Mediterranean ecosystem?

Straw helimulching was applied to an area with a high soil erosion risk one month after the Navalacruz megafire (Iberian Central System, Ávila, Spain) to mitigate soil erosion and to maintain soil quality. To determine whether the soil fungal community, which is key to soil and vegetation recovery after fire, is altered by straw mulching, we examined the effect of helimulching one year after its application. Three hillside zones were chosen with two treatments in each zone (mulched and non-mulched plots), with three replicates of each treatment. Chemical and genomic DNA analyses of soil samples from mulched and non-mulched plots were performed to assess the soil characteristics and the soil fungal community composition and abundance. The total fungal operational taxonomic unit richness and abundance did not differ between treatments. However, there was an increase in the richness of litter saprotrophs, plant pathogens and wood saprotrophs associated with the application of straw mulch. The total fungal composition of mulched and non-mulched plots differed significantly. Fungal composition at the phylum level correlated with the soil potassium content and marginally with the pH and phosphorus content. The application of mulch promoted the dominance of saprotrophic functional groups. Fungal composition according to guilds was also significantly different between treatments. As conclusion, the application of mulch could mean a faster recovery of saprotrophic functional groups that will be responsible for decomposing the available dead fine fuel.

Estimating Soil Erosion to Highlight Potential Areas for Conservation Priority in Rukarara Catchment, South-western Rwanda

Soil erosion is one of the major environmental problems in tropical ecosystems; however, the lack of information on the amount of eroded soils in Rwandan mountainous watersheds hinders effective decision-making toward sustainable soil management. This study aimed at predicting soil erosion in the Rukarara River watershed, one of the mountainous watersheds in Rwanda, and identifying potential areas of high erosion risk using the revised universal soil loss equation (RUSLE) implemented in a GIS environment. The annual soil loss was estimated by computing and performing a spatial overlay analysis of relevant layers including rainfall erosivity (R), soil erodability (K), slope length and steepness (LS), cover management (C), and conservation practice (P) factors. The results indicate that the annual soil erosion varies from 54 to 134 t ha−1 year−1 (95% confidence interval) with a mean of 39.96 t ha−1 year−1. The study area is generally characterized by very low and low soil erosion classes and the mean erosion correlated with literature results in the tropics. Agricultural lands are the hotspots of soil erosion with a mean of soil loss of 61.29 t ha−1 year−1. The produced maps and soil loss estimates can facilitate informed decision-making toward sustainable soil management in mountainous areas of Rwanda, especially in the Rukarara River watershed.

Using Dye and Bromide Tracers to Identify Preferential Water Flow in Agricultural Hillslope Soil under Controlled Conditions

Processes in hillslope soils present a particular challenge for agricultural production and soil management due to their hydropedological specifics and high soil erosion risk. Soil heterogeneities can cause preferential and/or lateral flow on the entire hillslope resulting in the off-site movement of water, fertilizers and chemicals used in crop production. A study was conducted under controlled conditions in a laboratory with undisturbed soil cores (250 cm3), which were used to estimate the soil hydraulic properties (SHP) using HYPROP and WP4C devices, while undisturbed soil columns (diameter = 16 cm, length = 25 cm) were used for the evaluation of preferential flow pathways using potassium bromide and Brilliant Blue. Samples were excavated in triplicate from the hilltop, backslope and footslope regions within the inter-rows of a vineyard from a critical zone observatory, SUPREHILL, in Croatia in Dystric Luvic Stagnosol. The aim of this study was to determine if the erosion-affected hillslope position affected the physical, chemical and hydraulic properties of soil and to identify water flow and possible preferential flow using dye and bromide tracers. The results of the sensor measurements and estimated SHPs were in agreement, showing a faster leaching of the irrigated rainwater in the footslope column. The tracer experiments showed variability even in the columns taken from the same position on the hillslope, which can be linked to plant roots and soil fauna activity. Altogether, the results showed a deeper loose layer at the footslope as a consequence of the soil erosion, which then resulted in higher hydraulic conductivity and the leached mass of the bromide due to better soil structure and pore connectivity. Thus, due to significant differences in the leached mass of bromide, this research should be later expanded in field experiments to reveal the impact of surface runoff, subsurface preferential and lateral flow on a larger scale.