Amount Of Soil Erosion Research Articles

Impacts of Land Use Conversion on Soil Erosion in the Urban Agglomeration on the Northern Slopes of the Tianshan Mountains

The serious problem of soil erosion not only has a profound impact on people’s lives but also results in a series of ecological and environmental challenges. To determine the impact of changes in land use type on soil erosion in the urban agglomeration on the northern slopes of the Tianshan Mountains, this study commences by employing the InVEST-SDR (integrated valuation of ecosystem services and tradeoffs–sediment delivery ratio) model to calculate soil erosion levels spanning from 2000 to 2020. Subsequently, it forecasts land use and land cover (LULC) conditions for the year 2030 under three scenarios: Q1 (natural development), Q2 (ecological protection), and Q3 (economic priority). This projection is accomplished through the integration of a coupled Markov chain and multi-objective planning model (MOP) alongside patch-generating land use simulation (PLUS) models. Ultimately, based on these outcomes, the study predicts soil erosion levels for the year 2030. There has been a consistent decline in soil erosion from 2000 to 2020 with high-intensity erosion concentrated in the Tianshan Mountain region. Grasslands, glaciers, and permafrost are identified as the most erosion-prone land types in the study area, with forests exhibiting the highest capacity for soil retention. Converting from grassland and barren land to forest within the same area results in a substantial reduction in soil erosion, specifically by 27.3% and 46.3%, respectively. Furthermore, the transformation from barren land to grassland also leads to a noteworthy 19% decrease in soil erosion. Over the past two decades, the study area has witnessed a significant decline in the area of grasslands, with a notable shift towards barren and impervious surfaces due to economic development and mining activities. The three predicted scenarios depict significant expansion towards barren land, grassland, and impervious area, respectively. Soil erosion decreases under different shared socio-economic pathway (SSP) scenarios relative to 2020. There is an increase in soil erosion in the Q1 scenario and in the Q3 scenario, whereas the amount of soil erosion in the Q2 scenario exhibits a continued decrease when only the effect of land change on soil erosion is considered. Persistently rapid economic development can exacerbate soil erosion problems, underscoring the need to find a balance between economic growth and ecological conservation. As economic expansion slows down, greater emphasis should be placed on environmental protection to maintain ecological stability.

Effects of sediment-storage dams on suspended sediment transport in the Sera Lake Watershed, northeast Turkey

In this study, the effects of cascade sediment-storage dams (SSDs) on the suspended sediment (SS) transport in the Sera Lake Watershed (northeast Turkey) were investigated. Ten SS monitoring stations from upstream (S01) to downstream (S10) were selected for the study considering the locations of the SSDs and Sera Lake. In a gauging station, where S05 was selected, the water stage monitoring studies were also conducted, and daily discharges and SS loads were computed. The Spearman correlation coefficient between SS and discharges data was computed as 0.592. The deterioration of the naturalness of the watershed with external interventions was effective on this value. While the Sera Lake trapped 33% of the SS transport, this value varied between –25.8 and 44% for SSDs. Although the SSDs have been proportionately succeed in trapping the SS, they have been insufficient in preventing sedimentation and problems caused by sediment transport in the watershed. In addition, the annual average soil erosion amount was determined by the revised universal soil loss equation (RUSLE) method in the watershed. According to the RUSLE method, the annual average soil loss of the watershed is 1.65 tons/ha. The SDR value of the watershed was calculated as 0.104. Integrating different environmental management tools to achieve a balanced and sustainable decision, a strategic environmental management plan should be constituted.

Response of road erosion to hydrological connectivity under a heavy rainstorm in an agricultural watershed on the Loess Plateau

Road network extension is closely associated with soil erosion in watersheds during frequent extreme rainfall events. Identifying potential risk areas that actively deliver surface runoff to road structures and channel networks is critical for comprehending hydrological processes and controlling road erosion. In this study, the road erosion (landslides, collapses, scour pits, and gullies on monitored roads) on the Loess Plateau during a heavy rainstorm was analyzed using field survey and unmanned aerial vehicle (UAV) data. We defined hydrological connections as the intersections of roads and channel networks, and the activated hydrological connections represent hydrological connectivity. The results of this study highlight the exacerbating effect of hydrological connectivity on road erosion during a rainstorm in an agricultural watershed in the Loess Plateau region. The results showed that the road erosion intensity ranged from 2.16 × 102 to 1.02 × 104 t/ha. Strong hydrological connectivity resulted in average soil erosion amounts of landslides, collapses, scour pits, and gullies in the downslope area that were 2.16, 1.78, 5.46, and 6.98 times greater than those without hydrological connectivity, respectively. The presence of hydrological connectivity generated a 1.88 times higher road surface erosion intensity than that without hydrological connectivity. The Upslope-Road connections created the most significant enhancement effect on road erosion, and up to 65.37 % landslide erosion and 41.97 % collapse erosion amounts were influenced by these connections.The enhancement effect of Upslope–Road connections on road erosion varied with different road types, this impact of Upslope–Road connections on road erosion were only observed on the landslide erosion of petroleum transport roads and the collapse erosion of agricultural roads. Conversely, Road–Downslope connections did not significantly impact road erosion (p > 0.05). To effectively control the negative effect of road erosion, hydrological connections should be identified and regulated to impede hydrological connectivity activation during rainstorms by modifying tillage activities, improving road maintenance, and strengthening drainage systems.

Soil erosion-based sub-watershed prioritization through coupling various crop management and erosivity scenarios using game theory

The soil erosion of the watershed is different in temporal and spatial scales due to complex climatic and environmental conditions and their dynamic state over time. Accordingly, it is necessary to prioritize sub-watersheds based on their dynamic conditions to reduce the destructive effects of soil erosion. However, this issue has to be sufficiently reported on the scale of the watershed. Towards that, a game theory-based prioritization approach was planned concerning changes in vegetation cover and rainfall in the Shazand Watershed of the Markazi Province, Iran. To achieve the purpose of the study, the amount of soil erosion was first estimated in different scenarios resulting from the changes in rainfall erosivity and vegetation cover using the RUSLE model. Next, pairwise comparisons between 24 sub-watersheds in all scenarios were made based on the sub-watersheds' ranks in soil erosion in each scenario. Considering all scenarios, the priority of the sub-watersheds was assessed using the Condorcet approach. The results showed that the mean soil erosion in the watershed ranged from 5.4 and 36 t ha−1 y−1 while applying various scenarios. It is worth mentioning that the prioritization results obtained from the Condorcet algorithm and the current soil erosion rate are highly similar. On the other hand, sub-watersheds 2 and 9 were selected as the first and last priority, providing an appropriate roadmap for managers and relevant departments to adopt appropriate soil erosion inhibition measures.

The Impact of Group- and Single-Tree-Selection Cuttings on Runoff and Sediment Yield in Mixed Broadleaved Forests, Northern Iran

Silvicultural treatment and the forest harvesting operations using different methods can lead to an increase in the production of runoff and sediment by changing the canopy and soil surface where they are conducted. In order to investigate this issue, sampling plots were established in the Namkhaneh district of the Kheyrud forest with three replications for every treatment: control stand and tree harvesting systems using single-selection cuttings and group-selection cuttings. The amount of runoff and sediment was collected and estimated from precipitation over a period of one year. Also, some soil physical properties such as bulk density, penetration resistance, sand, silt, and clay content, soil moisture, and soil organic matter were measured. The results showed that tree harvesting systems has a significant effect on runoff, the runoff coefficient, and sediment but the season (growing season and fall) and the combined effect of tree harvesting systems and the season have no significant effect on the runoff coefficient and sediment. The mean runoffs of each rainfall event for the control, single-tree, and group-selection treatments were 5.67, 8.42, and 10.28 mm, respectively, and the sediment amounts were 3.42, 6.70, and 11.82 gr/m2, respectively. Furthermore, the total annual erosion amounts of the control, selection, and grouping treatments were 0.427, 0.838, and 2.178 t/ha, respectively. The bulk density, penetration resistance, and percentage of sand and silt were positively related and the percentages of clay and organic matter were negatively related with the amount of runoff and sediment. In the method of individual selection cuttings, the damage to the forest in terms of the amount of runoff and soil erosion was less than for the group-selection cuttings. Forest harvesting by the selection method (single-selection and group-selection) has caused different changes in the vegetation canopy. The final summary of our results could be the advice to predominantly use the single-selection method in high-slope stands.

Soil erosion estimation and erosion risk area prioritization using GIS-based RUSLE model and identification of conservation strategies in Jejebe watershed, Southwestern Ethiopia.

Erosion of soil refers to the process of detaching and transporting topsoil from the land surface by natural forces such as water, wind, and other factors. As a result of this process, soil fertility is lost, water bodies' depth is reduced, water turbidity rises, and flood hazard problems, etc. Using a numerical model of erosion rates and erosion risks in the Jejebe watershed of the Baro Akobo basin in western Ethiopia, this study mapped erosion risks to prioritize conservation measures. In this study, the Revised Universal Soil Loss Equation (RUSLE) model was used, which was adapted to Ethiopian conditions. To estimate soil loss with RUSLE, the rainfall erosivity (R) factor was generated by interpolating rainfall data, the soil erodibility (K) factor was derived from the soil map, the topography (LS) factor was determined from the digital elevation model (DEM), cover and management (C) factor derived from the land use/cover data, and conservation practices (P) factor generated from digital elevation model (DEM) and land use/cover data were integrated with remote sensing data and the GIS 10.5 environment. The findings indicated that the watershed annual soil loss varies from nearly 0 on a gentle slope of forest lands to 265.8 t ha-1 year-1 in the very steep slope upper part of the watershed, with a mean annual soil loss of 36.2 t ha-1 year-1. The total annual soil loss in the watershed is estimated to be around 919,886.5 tons per year. To minimize the amount of soil erosion in the watershed that had been most severely affected, we identified eight conservation strategies that could be implemented. These strategies were based on the participatory watershed development (PWD) principles established by the Ethiopian government and the severity of the erosion in the watershed. The study's findings showed that a GIS-based RUSLE soil erosion assessment model can provide a realistic prediction of the amount of soil loss that will occur in the watershed. This tool can also help identify the priority areas for implementing effective erosion control measures.

Suitability of 210Pbex, 137Cs and 239+240Pu as soil erosion tracers in western Kenya

Land degradation resulting from soil erosion is a global concern, with the greatest risk in developing countries where food and land resources can be limited. The use of fallout radionuclides (FRNs) is a proven method for determining short and medium-term rates of soil erosion, to help improve our understanding of soil erosion processes. There has been limited use of these methods in tropical Africa due to the analytical challenges associated with 137Cs, where inventories are an order of magnitude lower than in the Europe. This research aimed to demonstrate the usability of 239+240Pu as a soil erosion tracer in western Kenya compared to conventional isotopes 210Pbex and 137Cs through the determination of FRN depth profiles at reference sites. Across six reference sites 239+240Pu showed the greatest potential, with the lowest coefficient of variation and the greatest peak-to-detection limit ratio of 640 compared to 5 and 1 for 210Pbex and 137Cs respectively. Additionally, 239+240Pu was the only radionuclide to meet the ‘allowable error’ threshold, demonstrating applicability to large scale studies in Western Kenya where the selection of suitable reference sites presents a significant challenge. The depth profile of 239+240Pu followed a polynomial function, with the maximum areal activities found between depths 3 and 12 cm, where thereafter areal activities decreased exponentially. As a result, 239+240Pu is presented as a robust tracer to evaluate soil erosion patterns and amounts in western Kenya, providing a powerful tool to inform and validate mitigation strategies with improved understanding of land degradation.

Assessment of the soil-protecting services of the forest ecosystem: a case study in Ilam catchment, Iran

Abstract The natural forests of western Iran play a key role in delivering services and goods to local society. Nonetheless, this forest ecosystem, despite its importance, is threatened by natural factors and anthropogenic activities, resulting in decreasing soil quality and soil erosion. The present research aimed to assess the effects of the forest ecosystems on soil erosion control in Ilam catchment in southwest Iran. For this purpose, after estimating the soil loss in natural conditions (NC), we predicted the amount of soil erosion under two scenarios: (i) convert natural forest with 20% canopy cover to destructed forest with 0% canopy cover (SC.1), (ii) increase forest cover by 40% (SC.2). Our results indicate that the estimated mean soil erosion was within the range of 9.36 t ha-1 yr-1 in irrigated and garden use to about 256 t ha-1 yr-1 in bare soils under NC. We found that when converting natural forest to destructed forest, the mean annual soil erosion rate increased 105.75 t ha-1 yr-1, 118.1 t ha-1 yr-1, and 19.57 t ha-1 yr-1 in the dense forest, sparse forest, and Agri-Forest use, respectively. These results show the protective effect of the forest against soil erosion.

Impacts of upslope inflow and soil pipe collapse on slope water erosion in the typical Chinese Mollisol region

Understanding the effects of upslope runoff and soil pipe collapse on slope water erosion can provide scien-tific basis for preventing Mollisol degradation caused by soil erosion. We conducted an experiment to investigate the effects of upslope inflow rate and soil pipe collapse on slope water erosion and to quantify the contribution of soil pipe erosion to slope soil erosion. The experiment included three inflow rates (30, 40, and 50 L·min-1) and three near-surface soil hydrological conditions (without soil pipe: NP; with soil pipe but no pipe flow: PF0; with pipe flow: PF1). The results showed that: 1) Slope soil erosion increased with increasing inflow rates; when the inflow rate increased from 30 L·min-1 to 40 and 50 L·min-1, slope soil erosion increased by 100.0%-111.5% and 214.8%-289.2%, respectively. 2) The soil pipe occurrence and pipe flow formation aggravated the slope water erosion process. At inflow rates of 30, 40, and 50 L·min-1, slope soil loss under the PF0 and PF1 treatments were 1.4-1.6 times and 1.7-2.1 times of that under the NP treatment. The contribution of soil pipe erosion to slope soil loss was 26.7%-37.6% under the PF0 treatment and 40.5%-51.9% under the PF1 treatment. 3) Soil pipe collapse intensified the rill erosion process. Compared with the NP treatment at 30, 40, and 50 L·min-1 inflow rate, rill erosion amounts under the PF0 and PF1 treatments increased by 38.1%-66.0% and by 93.7%-128.4%, respectively. Our results suggested that increasing upslope inflow rate resulted in higher surface runoff velocity, which promoted runoff detachment and transport capacity, and then aggrandized the amount of slope soil erosion. Moreover, soil pipe collapse exacerbated rill erosion process. When the soil pipe collapsed, all surface runoff was converted to soil pipe flow, which accelerated flow velocity and slope soil erosion process, and then increased the amount of slope soil erosion.

Assessing the Effects of Conservation Measures on Soil Erosion in Arasbaran Forests Using RUSLE

Vegetation cover is known as one of the most dominant parameters in soil erosion that can considerably affect soil erosion drivers. This study aimed to assess the effects of vegetation cover on soil conservation in Arasbaran Forests, Iran. A part of Arsbaran forests has been protected for 45 years. The other part has not been under protection during these years. This study was carried out in order to investigate the effects of forest protection management on the changes in the amount of soil erosion and compare it with the non-protection sector. To this end, 66 samples were grouped in the two selected elevation classes. Out of every three sample plots, one plot was randomly selected for collecting soil samples. Landsat 8 images and a Digital Elevation Model were utilized for sample collection via ENVI (Environment for Visualizing Images) and GIS (Geographic Information System), respectively. Then, the Revised Universal Soil Loss Equation (RUSLE) was employed to estimate the annual soil loss in the studied sites. The results showed the annual soil erosion of 9.84 and 10.06 tons per hectare/year for protected and non-protected areas, respectively. Moreover, the average annual soil erosion of 9.95 tons per hectare/year was calculated for the whole Arasbaran Forests. The results of the statistical test revealed no significant difference between protected and non-protected sites in terms of erosion rates (p > 0.05). Based on the findings, despite the non-significant and slightly lower soil loss per unit area in the protected site, there is a notable soil loss throughout the entire non-protected area. It appears necessary to conduct a thorough review of existing conservation laws and to closely monitor their effective implementation. This step is crucial for enhancing the effectiveness of forest conservation management in mitigating soil erosion. The results show that absolute forest protection alone cannot make a big difference in preventing soil erosion. In this regard, there is a need to carry silviculture measures to manage protected forest stands to increase the sustainability of the forest. Obviously, in the case of proper management along with protection, it is possible to have a greater effect in preventing soil erosion.

Compound erosion effect of snowmelt, wind, and rainfall on sloping farmlands of Chinese typical Mollisol region.

Research on the processes and mechanisms of compound soil erosion by multiple forces can provide scientific guidance for precisely controlling cropland soil erosion. Based on the seasonal alternation of freezing-thawing, snowmelt, wind, and rainfall erosion forces on sloping farmlands under natural conditions from November to next October of each year, we used a set of indoor simulation experiments of multi-force superimpositions to analyze the compound soil erosion processes of snowmelt (1 and 2 L·min-1), wind (12 m·s-1), and rainfall (100 mm·h-1). We further discussed the erosion effects of multi-force superimpositions. The results showed that, under single snowmelt erosion, an increase in snowmelt flow had a greater effect on sloping snowmelt erosion intensity than that of sloping runoff rate. When sloping snowmelt flow increased from 1 L·min-1 to 2 L·min-1, sloping runoff rate and erosion intensity increased by 2.7 and 4.0 times, respectively. Under snowmelt-wind superimposition erosion, previous sloping snowmelt erosion inhibited late wind erosion occurrence. As sloping snowmelt flow increased from 1 L·min-1 to 2 L·min-1, the inhibiting action subsequently increased and wind erosion intensity caused by previous snowmelt reduced by more than 50%. Both wind erosion and snowmelt-wind superimposed erosion intensified late rainfall erosion. The early wind erosion increased rainfall erosion by 24.5%. The snowmelt-wind superimposed effect increased the later slope rainfall erosion by 132.8% and 465.4% under 1 and 2 L·min-1 snowmelt runoff rates, respectively. The compound soil erosion amount driven by multiple force superimposition was not the sum of the corresponding erosion amount caused by single erosion force, with promoting or inhibiting effects of erosion force superimposition. The erosion effect of snowmelt-wind superposition was negative, but that of wind-rainfall superposition and snowmelt-wind-rainfall superpositions were positive.

Assessment of the Implementation Effect of a Gully Consolidation and Highland Protection (GCHP) Project Based on the GeoWEPP Model

The Gully Consolidation and Highland Protection (GCHP) project is an important governance measure for controlling source erosion and reducing soil erosion in the Loess Plateau, which has been explored and developed continuously in recent decades. However, there is no international precedent for research on the implementation effect of the GCHP project, and it is still relatively weak. In order to quantify the erosion of a small watershed under the construction of a gully head landfill, this study selected Yangjiagou (YJG) as the research area. The spatial analysis function of ArcGIS was used to process DEM and soil type data, the GeoWEPP model was used to simulate soil erosion, and the changes of runoff and sediment yield before and after gully head landfill were analyzed. The results showed that compared with the simulated original soil erosion amount, the annual runoff decreased by 13.13%, and the sediment yield decreased by 37.61% after gully head landfill, indicating that the GCHP project positively influenced soil erosion control. After the gully head landfill measures are taken, the flow path becomes shorter, so the flow scour capacity is weakened. Soil and water control is very effective in the short term, but if long-term maintenance is not carried out, the intensity of soil and water loss is likely to be aggravated. This study provides an effective verification method for the feasibility of a soil loss control scheme on the Loess Plateau and provides a reference for promoting ecological priority and efficient management in the Loess gully area. Ultimately, it will serve the ecological protection and high-quality development of the Yellow River Basin.

Assessing current and future soil erosion under changing land use based on InVEST and FLUS models in the Yihe River Basin, North China

The Yihe River Basin is a key area for water conservation and soil erosion control in northern China. The excessive development of land resources is a major factor causing soil erosion and ecological degradation. However, the impacts of land use change on soil erosion in the basin are not yet clearly. Understanding the complex relationship between land use and soil erosion is an important way to promote the development of land resources utilization and ecological construction from cognition to decision-making. This study simulated the temporal-spatial changes of soil erosion in the basin from 1956 to 2020 using Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, and evaluated the changes of soil erosion under different land use scenarios from 2020 to 2050 using Future Land Use Simulation (FLUS) model. From 1956 to 2020, the overall soil erosion intensity showed a slight decreasing trend, and the average annual soil erosion modulus was 38.21 t/ha/year. Soil erosion intensity was higher in the central and northern mountainous areas, while it was lower in the flat alluvial plains in the south. Arable land (4.07 t/ha/year) was the largest contributor to the amount of soil erosion, and land use changes caused the soil erosion intensity to fluctuate and decrease after 1995. From 2020 to 2050, soil erosion varied widely under different land use scenarios, and the land use pattern targeting ecological priority development would effectively mitigate soil erosion. Therefore, optimizing land use patterns and structures are critical initiatives to prevent soil erosion.

Estimation of surface soil erosion using the RUSLE Model of Jalpaiguri Sadar Block in Jalpaiguri District, West Bengal, India

Land degradation is a pervasive environmental and “economic challenge of the present time, especially in developing countries. Soil erosion caused by water is considered as one of the major types of land degradation processes. Soil loss estimation and detection of soil erosion-prone areas are the most important for agricultural planning and various other land management plannings in the recent era. The amount of annual average soil loss was calculated by using the Revised Universal Soil Loss Equation (RUSLE) model. This model was popularized for identifying soil loss zone areas or zones and soil erosion risk areas. This study provided a creditable prediction of soil erosion and the probable soil erosion severity zones of Jalpaiguri Sadar Block in Jalpaiguri District, West Bengal. GIS Environment was used to create the raster layer in the RUSLE factors. RUSLE data layers including rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover management (C), and conservation practice (P) factors were calculated to account for the average annual soil loss of the study area. The results of this work show that the range of soil erosion is >100.00 tons hac-1year-1 to <25.00 tons hac-1year-1 while the amount of soil erosion is more in the upper part of the Jalpaiguri Sadar block, mainly along the right bank of the Tista river and the bank of the Karala river, because the soil texture is very loose in nature and the area also receive heavy rainfall. Therefore, the high level of risk of soil erosion can be checked through the processes of various soil conservation techniques.

Using geochemical elements to discriminate sediment sources in a typical karst watershed

Knowledge of temporal variations in sediment sources is necessary to identify the principal sources of sediment for effective implementation of soil conservation measures and to improve the calibration and validation of process-based soil erosion models. Quantitative information on sediment provenance is often limited in karst regions because of their complex surfaces and underground three-dimensional erosion systems. Peak-cluster depressions are typical landforms in karst areas and can well intercept most sediment from hillsides such as dams or reservoirs. Thus, peak-cluster depressions are suitable areas for sediment source identification. The objective of this study was to quantify the contribution of sediment sources in a typical karst watershed and to identify temporal variations in sediment sources in the watershed in the past 60 years. We collected 194 soil samples from three sediment profiles in a karst depression and 58 source samples from cropland, fissure soil, and forestland. We used a composite fingerprinting method based on 45 geochemical properties and an IsoSource multivariate mixed model in a typical karst watershed. The results indicate that cropland was the principal sediment source (89.2 %) in the last 60 years, followed by fissure soil (9.6 %) and forestland (1.2 %). Importantly, compared with the period from 1949 to 1999, the contribution of sediment from fissure soil reached a maximum value of approximately 20 % from 1999 to 2015. This result implies that the “Grain for Green” program, which was implemented in 1999, clearly reduced the amount of soil erosion from cropland. Therefore, the program may greatly affect sediment deposition in karst depressions. Using metal ratios as fingerprint factors, the IsoSource mixed model can be effectively used to study the source of sediments in karst watersheds quantitatively. This study can aid the existing understanding of soil erosion processes and contributes to the sustainable development of agro-ecology in karst watersheds.

Trade-off analyses between food provision and soil conservation service of Grain for Green Program in Mountainous Area

The Grain for Green Program and soil and water conservation engineering initiatives are crucial for controlling erosion in steep-slope agriculture. However, it is still unclear how these two management methods should be carried out in respect to the situation in mountainous areas. Therefore, taking a typical mountainous area in southwest China as an example, we simulated six scenarios in order to compare the food provisioning service (FPS) and soil conservation service of the Grain for Green Program (converting to grassland) and Construction Measures (converting to sloping terrace) under different slopes. Results showed that when farmland with a >25° slope was converted into grassland, the amount of soil erosion (M) decreased by 21.0%, while FPS decreased by only 0.7%. However, when farmland with a >25° slope was converted into sloping terrace, M decreased by 31.3% while FPS increased by 18.7%. With the increases of farmland slope ranges in the Construction Measures scenario, M gradually decreased and FPS gradually increased. Particularly when farmland >15° was converted into sloping terrace, M decreased by 63.9% and FPS increased by 52.7%. Furthermore, the trade-offs of Construction Measures are lower than that of Grain for Green on different slope ranges. Therefore, we conclude that Construction Measures are a more suitable method in mountainous areas than the Grain for Green, and we suggest that further research be conducted to consider the ecological risks of construction engineering measures.

Application of Geo-informatics for Soil Erosion Mapping

Soil erosion is a most severe environmental problem in hilly area. The study is carried out on Upper Bagmati River basin, North of Kathmandu valley having an area of 61 Sq.km. (approx). Universal Soil Loss Equation (USLE) model, with Geographic Information System (GIS) has been used to quantify the soil loss. Erosion modelling requires huge amount of information and data, usually coming from different sources and available in different formats and scales and for management of these data, GIS was used, which helped considerably in organizing the spatial data representing the effects of each factor affecting soil erosion. Five essential parameters of USLE Rainfall erosivity factor (R), Soil erodibility Factor (K), Slope length and steepness (LS) factor, Cropping management factor (C) and Support practice factor (P) have been used to estimate soil loss amount in the study area. All of these layers have been prepared in Arc GIS using various data sources and data preparation methods. DEM was prepared from the contour data with the interval of 20m which was used to generate LS factor. The monthly rainfall data (2010) of 17 rain gauge stations within the catchment area have been used to predict the R factor. K, C and P factors in basin area are adopted from the literature. The spatial distribution map of soil loss of the basin has been generated and classified into six categories depending on the calculated soil erosion amount. The annual predicted soil loss ranges between 0 and 292.878 t/ha/y. Low soil loss (mean 9.7 t/ha/y) have been recorded under forested areas. The high rate (mean 40.4 t/ha/y) of soil erosion was found in the cultivation area.

Evaluating land degradation by gully erosion through soil erosion indices and rainfall thresholds

Among the land degradation processes, gully erosion is the one that poses more environmental and societal challenges in arid regions. Predicting spatiotemporal gully development in a region under changing conditions is important to adopt proper mitigation measures. Here we investigate the Ghapan-Olya watershed in Golestan province in Iran, which is affected by many erosional landforms, including gully phenomena. We apply the pixel-based distributed LANDPLANER model to predict where rainfall induced gullies will occur by exploiting input maps including UAV data, the region soil, and seasonal land use information. We compare our topographic thresholds and an erosion index with field observations through the application of quantitative metrics such as sensitivity, specificity, fallout, precision, and recall. Our study reveals that the spatial density of the gully’s location is more frequently predicted in the areas with an altitude of about 200–300 m, steep slope (between 15 and 30 degrees), and low average accumulation value (< 100) in the southeast facing slope. We obtain higher values of erosion index and topographic threshold for the minimum curve number where intense rainfalls are more frequent and where land use and cover conditions are more predisposing for gully occurrence. We obtain the largest values of soil erosion indices in the fall scenario when the daily rainfall is 80 mm (6.27), followed by the summer scenario with 80 mm daily rainfall (4.88), and spring again with 80 mm daily rainfall (2.99). In addition, topographic threshold maps illustrate the largest amount of soil erosion for the curve number scenario (without considering daily rainfall) in autumn. Our approach allows simulating gully erosion under changing conditions.

Analysis of the Effect of Soil Erosion in Abandoned Agricultural Areas: The Case of NE Area of Basilicata Region (Southern Italy)

Land abandonment is among the most complex la nd use change processes driven by a multiplicity of anthropogenic and natural factors, such as agricultural over-exploitation, implementation of agricultural policies, socio-economic and climatic aspects. Therefore, it is necessary to deepen the effects of land abandonment based on methodologies that are as multidisciplinary as possible. Environmental and social problems related to abandonment include soil erosion and environmental degradation. Approaches combining GIS (Geographic Information System), remote sensing, and image analysis techniques allow for assessments and predictions based on integrating theoretical models with advanced geospatial and geostatistical models. One of the most widely used models for soil erosion estimation is the Revised Universal Soil Loss Equation (RUSLE). The present work developed a model using remote sensing and GIS tools to investigate some factors of the RUSLE equation to evaluate the adverse effects of soil erosion in areas covered by arable crops and subsequently abandoned. To identify potentially degraded areas, two factors of the RUSLE were related: the C Factor describing the vegetation cover of the soil and the A Factor representing the amount of potential soil erosion. Through statistical correlation analysis with the RUSLE factors, based on the deviations from the average erosion values and mapping of the areas of vegetation degradation relating to arable land, the areas identified and mapped are susceptible to soil degradation.

Spatiotemporal Variation of Soil Erosion Characteristics in the Qinghai Lake Basin Based on the InVEST Model

The present study aims to quantitatively assess soil erosion intensity (SEI) and amounts in the Qinghai Lake Basin (QLB) over the 1990-2020 period using the Integrated Valuation Ecosystem Services and Tradeoffs (InVEST) model based on multi-source data. In addition, the changing trends and driving factors of soil erosion (SE) in the study area were systematically analyzed. The result showed: (1) An increasing-decreasing trend in the total soil erosion amount (SEA) in the QLB over the 1990-2020 period, with an average SEI of 579.52 t/km2. In addition, very low and low erosion classes covered 94.49% of the total surface area, while areas with high SEI were mainly distributed in alpine areas with low vegetation coverage (VC). (2) The highest average SEI was observed in bare land, while grassland and unused land were the main land use (LU) types where SE mainly occurred, with the ratio of the two being 95.78%. (3) The average value of SEI was positively correlated with altitude values below 4800 m. In addition, areas with altitude ranges of 4000-4400 m, 3600-4000 m, and 4400-4800 m were the main areas where SE occurred, with an average total soil erosion ratio (SER) value of 88.73%. (4) The average SEI was directly proportional to the slope degrees. SE occurred mainly in the areas with slope degree ranges of 15-25°, 25-35°, 8-15°, and >35°, accounting for 93.16% of the average total SER value. (5) The q value of the two-factor interaction was greater than that of the single-factor interaction. In addition, the areas with a high SE risk were mainly those with 1220-2510 m rainfall, <0.104 VC, the land use/land cover (LULC) type bare land, the altitude range 4400-4800 m, and a slope of >35°. The interaction between rainfall, VC, LULC, elevation, and slope had a significant impact on the spatial distribution of SEI.