Soil Erosion Protection Research Articles

Exploring the Adaptation of Native Shrub Species to Different Levels of Shading: Augmenting their Sustainable Exploitation Framework

Abstract The environmental adaptation potential of regional wild germplasm resources should be investigated in a species-specific manner in terms of the sustainable exploitation of underutilized native species. In the current work, three fruit/ornamental shrub species (Rosa canina L., Sambucus nigra L. and Cornus sanguinea L.) originating from regional wild germplasm of Greece with a previously set domestication framework have been investigated in terms of their environmental adaptation to different levels of shading. To this end, targeted experimentation was conducted on ex situ adapted material by applying different shading levels (0%, 30% and 60% shading) in purpose-built netting tunnels. Rosa canina showed similar growth patterns among the shading levels applied but with increased chlorophyll fluorescence patterns and increased abaxial leaf stomatal density with increased shading. Sambucus nigra showed similar results to R. canina in photosynthetic efficiency and leaf stomatal density but with additional effects on plant growth patterns. Cornus sanguinea, on the other hand, was not affected by shading level in the measured parameters. These results outline the adaptation potential in a species-specific manner of the studied species to shading in terms of adding novel exploitation options for agroecosystems, agroforestry, and landscape management in peri-urban green spaces and peri-urban forest understory enrichment to mitigate climate change impacts in temperate and semi-arid climates. Study Implications: This study explores the adaptation potential to increasing levels of shading of ex situ adapted germplasm of wild origin of three underutilized shrub species with known multifaceted value. The work builds on the sustainable utilization framework of the focal species in terms of novel exploitation options in landscape management for peri-urban green spaces and peri-urban forest understory enrichment for enhancing biodiversity and soil erosion protection. Therefore, this work offers an example of an underlying research line towards systematized screening and utilization of wild plant species for climate change impact mitigation in agroecosystems, agroforestry, and landscape management in temperate semi-arid climates.

Estimating the Extent of Water Erosion in Darbandikhan Lake Using a Model Gavrilović Method (EPM) (Erosion Potential Method)

Through the research, it became evident that the soil erosion protection index (Xa) in the very severe category appears to correlate with the spatial distribution of vegetation cover. It covers an area of 80.73 km2, accounting for 17.54%. However, the very weak category is among the weakest in soil protection, occupying areas characterized by water bodies, covering an area of 49.65 km2, or 10.79%. The probability erosion coefficient (Z) indicates a very weak probability of erosion, covering an area of 143.19 km2, or 31.11%. Thes means that 31.11% of the total study area of 460.21 km2 is subject to very weak erosion. The last category, very severe potential erosion, is the least extensive, covering an area of 21.06 km 2, or 4.58%. Regarding the amount of soil lost in the study area, apparent erosion ranges from 0.29 to 50 m3/km2/year. This category is prevalent in the northeastern and northwestern parts, with a clear concentration in the northern parts, covering an area of 35.04 km2, or 7.61%. Severe erosion ranges from 501 to 1500 m3/km2/year, making it the least extensive category in the region, covering the smallest area among the categories, at 19.92 km2, or 4.33%.

Thermal conductivity of dried biocemented sand at higher calcification

Thermal conductivity of dried biocemented sand at higher calcification

Study on soil erosion and its driving factors from the perspective of landscape in Xiushui watershed, China

Soil erosion (SE) is one of the most serious disasters in the world, which directly damage the productivity of the land and affect human well-being. How to effectively mitigate soil erosion is a challenge faced by all countries in the world. In this study, soil erosion was quantitatively assessed base on the RULSE model in an ecologically fragile area [Xiushui watershed (XSW)], and the effects of three major categories of factors (land use/cover change, landscape fragmentation and climate) on soil erosion were investigated using correlation analysis and structural equation model. The results indicated that there was no continuous increase or decrease trend on the SE of XSW with impact of rainfall, the mean values of SE were 2205.27 t/ha, 3414.25 t/ha and 3319.44 t/ha from 2000 to 2020 and the hot areas of SE were mainly distributed around the Xiushui river channel, respectively. The expansion of urbanization (the area of impervious increased from 113.12 to 252.57 km2) aggravated landscape fragmentation, and the landscape fragmented area had some overlap with the hot zone of SE. Additionally, the LUCC factor dominated by NDVI, landscape fragmentation factor and climate factor dominated by rainfall had a directly driving effect on SE, where the path coefficient of landscape fragmentation was 0.61 (P < 0.01), respectively. We also found that except increasing forest area, improving forest quality (NDVI, canopy closure, structure) deserved emphasized in SE management, and the effect of landscape fragmentation on SE also should not be ignored. Moreover, soil erosion assessment at large scales over long time periods tends to underestimate the driving force of rainfall on SE, and it is a great challenge to evaluate the effect of extreme rainfall on soil erosion at short time scales in a downscale manner. This research provides insights for ecological sustainable management and soil erosion protection policies.

Analysis of the sediment sources of flood driven erosion and deposition in the river channel of the Fu River Basin

Studying the characteristics of runoff and sediment processes and revealing the sources of sediment provide key guidance for the scientific formulation of relevant soil erosion protection measures and water conservancy development plans. In the current study, the flow and sediment data of five hydrological stations on the main stream of the Fu River Basin (FRB) from 2007 to 2018 were selected to identify flood events, explore the variation of sediment transport along the FRB, and clarify the sediment sources. The results found that the Jiangyou–Fujiangqiao section is the main source of sediment in the FRB during the flood season. The runoff volume and sediment load during flood events in the Jiangyou–Fujiangqiao section accounted for 35% and 145% respectively of that of Xiaoheba station. These results combined with the change of the sediment load before and after the 2008 Wenchuan Earthquake (May 12) show that the sediment in this section mainly comes from the Fu River tributary–the Tongkou River watershed. The calculation results for the sediment carrying capacity of the Fu River show that the main stream was in a state of erosion in theory. However, according to the calculation results for the interval sediment yield during flood events, the sediment load at the Xiaoheba station was smaller than that at the Shehong station upstream. The analysis indicates that this was not because of sediment deposition in the river channel, but because of sand mining in the river channel and sediment interception by water conservancy projects. If heavy rainfall occurs in the FRB, the sediment accumulated upstream will move downstream with the resulting flood, and the sediment yield in the FRB may further increase. These research conclusions can provide reference information for improving the prediction and management ability of soil and water loss in the FRB and scientific regulation of the Three Gorges Reservoir.

Self-Organizing Feature Zoning and Multiple Hotspots Identification of Ecosystem Services: How to Promote Ecological Refined Management of Chengdu-Chongqing Urban Agglomeration

Reasonable ecological function zoning is conducive to balancing ecological security and social development. Previous studies of evaluation for urban ecosystem services (ESs) have great progress. However, there is a lack of integrating ES stable hotspots into urban planning and refined management. In this research, we are interested in how hotspot identification can help promote ecological refined management. To achieve this, Chengdu-Chongqing urban agglomeration (CY) was chosen as a case study. First, we employed coefficient of variation and linear regression to analyze ESs temporal and spatial evolution trend from 2000 to 2017. Then, the stable ES hotspots were identified in the time dimension, and the results were superimposed on the dominant function zoning map obtained by a self-organizing feature map (SOFM). Finally, the refined zoning results were obtained, and we added corresponding control measures and policy guidance. The results showed the following: (1) from 2000 to 2017, water conservation (WR) and biodiversity conservation (Sbio) in the study area fluctuated greatly and showed a significant improvement trend on the whole; soil erosion protection (Spro), carbon sequestration and oxygen production (CSOP) showed a degradation trend in a few areas; (2) the area with at least one kind of ES stable hotspot accounted for 35.22% in the study area, and only 0.8% covered the four kinds of ES hotspots; and (3) the two-level zoning system of CY-refined management was designed. Eighteen cells have been designed within five main functional zones: urban agglomeration zone, modern agricultural development zone, ecological farming zone, ecological transition zone, and core ecological protection zone. Overall, the research based on natural ecological zoning management can provide a decision-making basis for urban planning, policy making, and sustainable development.

Tree insect pests and pathogens: a global systematic review of their impacts in urban areas

Trees contribute greatly to urban environments and human well-being, yet relatively little is known about the extent to which a rising incidence of tree insect pests and pathogens may be affecting these contributions. To address this issue, we undertook a systematic review and synthesis of the diverse global empirical evidence on the impacts of urban tree insect pests and pathogens, using bibliographic databases. Following screening and appraisal of over 3000 articles from a wide range of fields, 100 studies from 28 countries, spanning 1979–2021, were conceptually sorted into a three-part framework: (1) environmental impacts, representing 95 of the studies, including those reporting on tree damage, mortality, reduced growth, and changes in tree function; (2) social impacts were reported by 35 of studies, including on aesthetics, human health, and safety hazards; and (3) economic impacts, reported in 24 of studies, including on costs of pest management, and economic losses. There has been a considerable increase in urban impact studies since 2011. Evidence gaps exist on impacts on climate-regulating capacity, including temperature regulation, water retention, soil erosion, and wind protection, but also on specific hazards, nuisances, human well-being, property damages, and hazard liabilities. As a knowledge synthesis, this article presents the best available evidence of urban tree insect / pathogen impacts to guide policy, management and further research. It will enable us to better forecast how growing threats will affect the urban forest and plan for these eventualities.

Spatial and Temporal Changes in Vegetation Cover in the Three North Protection Forest Project Area Supported by GEE Cloud Platform

The alterations in vegetation cover in the Three North Protection Forest Project area influence its ecological and environmental management. It helps to study soil erosion, environmental change, and ecosystem protection to provide basic data support. Based on the Google Earth Engine cloud platform, this paper selects MODIS 3Q1 data from 2000–2020 and uses the image element dichotomous model to estimate the fractional vegetation cover (FVC) of the Three North Protection Forest Project area, evaluates the stability and temporal and spatial variation of FVC, investigates the coupling relationship between the FVC and temperature and rainfall through evaluation indexes such as the slope of inter-annual variation and partial correlation coefficient, and then analyzes the influence of land use changes on the FVC. The results show that the fractional vegetation cover of the Three North Protection Forest Project area as a whole has increased significantly over the past 20 years, the medium and high vegetation coverage areas have reached 36.4%, the high vegetation FVC has increased from 20.66% in 2000 to 21.59% in 2020, and the vegetation activity is increasing. The vegetation cover is significantly affected by the topographic effect, with the vegetation cover improving relatively well at slopes between 5–13° and elevations ranging from 2000–2500 m. The overall positive correlation between vegetation and temperature and vegetation and precipitation in the study area was 54.08% and 70.04%, respectively, and precipitation was the key factor influencing vegetation growth in the research region. Human activities have a stronger effect on vegetation construction than destruction, and this study contributes to the evaluation of the benefits of the Three North Protection Forest Project and the understanding of human influence on environmental change.

The complete chloroplast genome sequence of Castanopsis fordii Hance (Fagaceae)

Castanopsis fordii Hance 1884 is a typical evergreen broad-leaved forest plant in the south subtropical and middle subtropical regions of China. It has high utilization value in wood production and soil erosion protection. Here, we first reported and characterized the complete chloroplast (cp) genome sequence of C. fordii based on Illumina paired-end sequencing data. The complete cp genome sequence of C. fordii was 160,853 base pairs (bp) in length which contained two inverted repeats (IRs) of 25,699 bp separated by a large single-copy (LSC) and a small single copy (SSC) of 90,474 bp and 18,981 bp, respectively. The cpDNA contained 129 genes, comprising 85 protein-coding genes, 36 tRNA genes, 8 rRNA genes. The overall GC content of the plastome was 36.8%. Phylogenetic analysis base on 14 chloroplast genomes indicated that C. fordii was closely related to the species C. tibetana and C. concinna in Fagaceae.

Tracking Changing Evidence of Water Erosion in Ordos Plateau, China Using the Google Earth Engine

Ordos Plateau is one of the primary sources of sediment in the Yellow River, and changes in regional soil erosion directly affect the ecological status of the lower reaches of the Yellow River. Many recent studies have been published using remote sensing (RS) and geographic information systems (GIS) to evaluate soil erosion. In this study, much satellite remote sensing data in the Google Earth Engine (GEE) can better track soil erosion protection, which is significant in guiding the ecological protection and restoration of the Ordos Plateau and the Yellow River basin. In this study, we used GEE to observe the changes in soil erosion in the Ordos area from 2013 to 2021. The Theil–Sen procedure and Mann–Kendall significance test methods were used to evaluate the trend of land erosion in the Ordos area from 2013 to 2021. Based on GEE, the RUSLE is applied to evaluate soil erosion and analyze the changing trend. As a result, (1) we found that the annual change of soil and water loss in the Ordos Plateau showed three stages: 2013–2015, 2016–2018, and 2018–2021. After 2018, soil loss decreased from 14 × 1017 Mg in 2018 to 4 × 1017 Mg in 2021, which indicates that the environmental restoration project started in 2018 has achieved encouraging results. (2) The results showed that 40.9% of the regional soil erosion trend showed a significant decline, and 45.7% of the regional soil erosion trend showed a slight decline. Only 13.3% of the regional soil erosion is on the rise. (3) The test results of different land use types show that 87.3% of soil erosion occurs in bare and cultivated land. Because the terrain of Ordos is relatively flat, 95.39–96.17% of soil erosion occurs in areas with a slope of 0 to 5. (4) The reliability of the RUSLE model based on the GEE platform is proved by regression model verification of observation data and model prediction results. (5) GEE’s cloud-based features can provide data and scripts to users in developing countries which lack sufficient observation data or the necessary computing resources to develop these data. The results show that GEE has robust analysis and processing ability, can analyze a large amount of data, and can provide efficient digital products for soil erosion research.

Agricultural heritage systems and agrobiodiversity

Agriculture is one of the main human activities with direct and indirect effects on the environment. The abandonment of many traditional agricultural practices, mainly for their inability to meet the current requirements of industrial agriculture, has brought to unsustainable agricultural systems characterized by high external energy inputs and by a high fragility to environmental and political shocks. Therefore, sustainable agriculture is nowadays crucial for preserving the environment. Agricultural heritage systems are receiving increasing attention at the international level, as testified by the establishment of the Globally Important Agricultural Heritage Systems (GIAHS) Programme by the Food and Agriculture Organization (FAO). The aim of the GIAHS Programme is, in fact, to identify and safeguard agro-silvo-pastoral systems resulting from the co-existence between humans and nature, which survived using traditional techniques are still providing many ecosystem services, while maintaining magnificent landscapes, wild and agricultural biodiversity, ancestral knowledge, and strong cultural and social values. These systems, based on sustainable practices, are still able to provide food and livelihood security, resources and services to local communities, but are also examples of adaptation and mitigation to climate change and to different and often difficult environmental conditions, as well as models of resilience and sustainability. In 2018 the Italian Agency for Development Cooperation (AICS), together with the Department of Agriculture, Food, Environment and Forestry (DAGRI) of the University of Florence, developed a project called “GIAHS Building Capacity”, aimed at identifying agricultural heritage sites in different parts of the world. This Special Issue collects the results of investigations carried out in thirteen sites in Central and South America, Europe, Africa and Asia offering a wide an coherent perspective on agricultural heritage systems across the world. The papers included in the Special Issue proved that agricultural heritage systems, despite some vulnerabilities mainly due to socio-economic causes rather than to environmental ones, still provide different ecosystem services to local communities, including: food and byproducts supply, soil erosion protection, hydrogeological risk and deforestation defense, agrobiodiversity and biodiversity conservation, cultural landscape preservation, agro-tourism; at the same time they can be important for transmitting traditional knowledge to new generations and for the local identity. The GIAHS programme can play a key role in preserving traditional agricultural systems, and their related agrobiodiversity and ecosystem services, both in developing and developed countries. In fact, its aim is not limited to the conservation of these systems, but the whole Programme is based on the concept of dynamic conservation, as sustainable innovations are needed for the preservation of agricultural heritage systems and, therefore, for the future of rural areas and of rural communities. The research is part of the activities promoted by the UNESCO Chair on Agricultural Heritage Landscapes established at the University of Florence.

Identification of Infiltration Features and Hydraulic Properties of Soils Based on Crop Water Stress Derived from Remotely Sensed Data

Knowledge of the spatial variability of soil hydraulic properties is important for many reasons, e.g., for soil erosion protection, or the assessment of surface and subsurface runoff. Nowadays, precision agriculture is gaining importance for which knowledge of soil hydraulic properties is essential, especially when it comes to the optimization of nitrogen fertilization. The present work aimed to exploit the ability of vegetation cover to identify the spatial variability of soil hydraulic properties through the expression of water stress. The assessment of the spatial distribution of saturated soil hydraulic conductivity (Ks) and field water capacity (FWC) was based on a combination of ground-based measurements and thermal and hyperspectral airborne imaging data. The crop water stress index (CWSI) was used as an indicator of crop water stress to assess the hydraulic properties of the soil. Supplementary vegetation indices were used. The support vector regression (SVR) method was used to estimate soil hydraulic properties from aerial data. Data analysis showed that the approach estimated Ks with good results (R2 = 0.77) for stands with developed crop water stress. The regression coefficient values for estimation of FWC for topsoil (0–0.3 m) ranged from R2 = 0.38 to R2 = 0.99. The differences within the study sites of the FWC estimations were higher for the subsoil layer (0.3–0.6 m). R2 values ranged from 0.12 to 0.99. Several factors affect the quality of the soil hydraulic features estimation, such as crop water stress development, condition of the crops, period and time of imaging, etc. The above approach is useful for practical applications for its relative simplicity, especially in precision agriculture.

Entrapment of clay particles enhances durability of bacterial biofilm-associated bioclogging in sand

Utilization of bacterial biofilms and extracellular polymeric substances (EPS) for engineered bioclogging has recently garnered increasing attention in various geotechnical practices, such as leakage sealing in water-front structures, soil erosion protection, earthquake-induced liquefaction mitigation, and hydraulic barrier installation. However, the long-term durability is still questioned as to how long the biofilm-associated bioclogging would last as the biofilms readily degrade in nutrient-poor conditions. Therefore, we explore the feasibility of using fine clay particles to enhance the durability of biofilm-induced bioclogging. A series of column experiments were performed to compare the clogging durability of bentonite-associated biofilms against that of biofilms only. The results confirmed that a continuous feed of nutrients to the model bacteria, Bacillus subtilis, stimulated biofilm formation and caused a ~ 99% reduction in hydraulic conductivity of sands. However, nutrient-poor fluid flow caused instantaneous sloughing of biofilms and removal of bioclogging. By contrast, bioclogging associated with bentonite–biofilm aggregates demonstrated enhanced durability against shear detachment by fluid flows in a starved condition. EPS analysis and SEM imaging revealed that bentonite particles in the introduced suspension formed aggregates with biofilms by coating and being embedded within biofilms. This study suggests that the exploitation of bentonite–biofilm aggregations can remarkably enhance bioclogging durability in nutrient-poor conditions. This coupled clay–biofilm clogging approach is expected to provide benefits in developing a strategy for engineered bioclogging in geotechnical practices.

Comparison of Topsoil Organic Carbon Stocks on Slopes under Soil-Protecting Forests in Relation to the Adjacent Agricultural Slopes

Soil erosion is one of the major processes degrading the natural environment but also agricultural production areas. Soil erosion may lead to soil organic carbon (SOC) loss, especially from sloping agricultural terrain units. The use of phytomelioration in environmental management, particularly long-term, permanent forest vegetation, is widely recognized as a possible measure for soil erosion protection and mitigation of climate change through carbon sequestration. The aim of this study was to compare of the topsoil organic carbon stocks on the slopes under soil-protecting forests in relation to the adjacent agricultural slopes. The research was conducted in the young glacial landscape of North-Central Poland. The study indicated the significant role of forest management on the increase of soil organic matter content and SOC stock. The results show that land use and slope gradients are important factors controlling soil organic carbon pools in topsoil in young glacial areas. This topic is extremely important particularly as the effects of climate change become more and more visible, and society faces new challenges in preventing these changes.

Social Demand for Ecosystem Services Provided by Peri-Urban Forests: the Case Study of the Tlemcen Forest (Algeria)

Recently, many studies have highlighted the role of urban and peri-urban forests in mitigating environmental pollution and maintaining human quality of life by integrating the concepts of ecosystem services into forest management strategy. To increase the social acceptance and to reduce the conflicts between users, citizens' preferences towards ecosystem services should be included in the decision-making process. In the present study, a structured questionnaire was administered to a sample of 180 citizens and 50 forest managers of the Tlemcen peri-urban forest (Algeria). The collected data was processed to show convergent and different preferences between forest managers and citizens towards the main categories of ecosystem services -- provisioning, regulating, supporting, and cultural services -- provided by the Tlemcen peri-urban forest. The results show that for both groups of respondents the three most important ecosystem services are: tourism and recreation (cultural services), soil erosion protection (regulating services), and biodiversity conservation (supporting services). Conversely, provisioning services (wood and non-wood forest products) are considered marginal by the two groups of respondents. These results are in line with international literature, which highlights in post-modern society an increase in importance of intrinsic values of nature at the expense of instrumental values.

Opinions towards the water‐related Payments for Ecosystem Services (PES) schemes: The stakeholders’ point of view

AbstractSustainable forest management provides a wide range of water‐related ecosystem services (WES) fundamental for human well‐being such as groundwater recharge, runoff and water discharge to streams, soil erosion protection, and recreational opportunities. Payments for Ecosystem Services (PES) promote sustainable forest management by reducing negative externalities. To implement PES schemes, many stakeholders with different interests and needs must be involved in the design and implementation process. The aim of this study is to investigate stakeholders’ opinions on the relationships between forests and water resources and the water‐related PES schemes in Italy. A semi‐structured questionnaire was administered to a sample of stakeholders. The results show that the most important WES provided by forests are soil erosion reduction, provision of habitats for different species, surface runoff reduction. The respondents emphasize the importance of regulating and supporting services, while they minimize the importance of cultural services related to the water resource.

RUSLE Model Based Annual Soil Loss Quantification for Soil Erosion Protection: A Case of Fincha Catchment, Ethiopia

In this study, Revised Universal Soil Loss Equation (RUSLE) model and Geographic Information System (GIS) platforms were successfully applied to quantify the annual soil loss for the protection of soil erosion in Fincha catchment, Ethiopia. The key physical factors such as rainfall erosivity ( R-factor), soil erodibility ( K-factor), topographic condition (LS-factor), cover management ( C-factor), and support practice ( P-factor) were prepared in GIS environment from rainfall, soil, Digital Elevation Model (DEM), Land use/Land cover (LULC) respectively. The RUSLE equation was used in raster calculator of ArcGIS spatial tool analyst. The individual map of the derived factors was multiplied in the raster calculator and an average annual soil loss ranges from 0.0 to 76.5 t ha−1 yr−1 was estimated. The estimated annual soil loss was categorized based on the qualitative and quantitative classifications as Very Low (0–15 t ha−1 yr−1), Low (15–45 t ha−1 yr−1), Moderate (45–75 t ha−1 yr−1), and High (&gt;75 t ha−1 yr−1). It was found from the generated soil erosion severity map that about 45% of the catchment area was vulnerable to the erosion with an annual soil loss of (&gt;75 t ha−1 yr−1), and this demonstrates that the erosion reduction actions are immediately required to ensure the sustainable soil resources in the study area. The soil erosion severity map generated based on RUSLE model and GIS platforms have a paramount role to alert all stakeholders in controlling the effects of the erosion. The results of the RUSLE model can also be further considered along with the catchment for practical soil loss protection practices.

Understanding Soil Erosion Protection Capabilities of Four Different Plants on Silty Soil

Soil is a natural wealth to human which need to be preserved, huge amount of soil is normally eroded due to rain and other activities, also anthropogenic occurrences increases the chance of erosion. Multiple methods are being employed to preserve soil erosion along hill slopes but all most of them end up as non-viable or costly. Vegetation plays key role in protecting soil from erosion, presence of vegetation increases the soil burden stability along slopes which increases the shear strength and reduce the soil erosion. In this work we had tried to study the soil binding nature of four different plant roots via soil bioengineering procedures. Primary aim of this paper is to obtain information related to the method of soil binding by the plant roots on silty-clay soil. We had studied the root growth nature and how they really tie up the soil as a monolithic mass to provide soil erosion protection. Plants were grown in pot culture allowing the plants to reach full root growth potential since roots play major role in protection soil from erosion. Triaxial shearing tests were conducted on the soil-root mass obtained using cores from soil. Also pull out tests were done to obtain the load required to pull out a fully grown root which indicates its composite ability. Also, root properties like Root Area Ratio (RAR), Root Biomass (RB), Tensile strength of root, root angle, thickness of root, deep rooting, root length density, root decay rate.

Reassessment of the potential risk of soil erosion by water on agricultural land in Germany: Setting the stage for site-appropriate decision-making in soil and water resources management

Accelerated soil erosion by water on agricultural land is considered one of the most critical forms of soil degradation, as it threatens both agronomic productivity and environmental quality. Given that both the costs and the benefits of soil erosion control measures are subject to spatial variation, the criterion of cost-effectiveness calls for spatially heterogeneous soil conservation policies. Under the German Direct Payments Regulation, federal state authorities are obliged to assess the potential risk of soil erosion by water on arable land in accordance with ABAG – the German version of the well-established Universal Soil Loss Equation (USLE) – and to impose appropriate management restrictions on farmers. However, the responsible federal state authorities have considerable degrees of freedom with regard to the methodology of erosion modelling - and thus in the designation of soil erosion protection areas: First, classification is carried out by multiplication of soil erodibility (K) and slope steepness (S) factors; the inclusion of rainfall erosivity (R) and slope length (L) factors is only optional. Second, classification of RKS- and RKLS-factors corresponds to the assumption of cross-regional standard estimates for R and L, which do not adequately reflect the heterogeneity of local conditions. This inevitably leads to over- and underestimation of local soil erosion hazards. As a consequence, the official risk assessment of soil erosion by water in Germany consists of a patchwork of cadastral risk maps at federal state level, which are neither publicly available nor fully comparable with each other. Hence, under current legislation there is a great danger that management requirements will be imposed on German farmers, which are economically inefficient, distort competition and do not achieve their environmental objectives. The aim of this study is to identify methodological and conceptual potential for improvement and harmonization in the risk assessment of soil erosion by water in Germany. For this purpose, high-resolution nationwide maps of rainfall erosivity (R-factor), soil erodibility (K-factor), slope length (L-factor), and slope steepness (S-factor) are produced in accordance with the revised ABAG using High Performance Computing (HPC) resources. The study area covers arable land, permanent grassland, vineyards, and orchard plantations. The modelling shows that the potential risk of soil erosion by water on agricultural land in Germany is much higher than previously assumed.

APPLICATION OF THE ANALYTIC HIERARCHY PROCESS FOR MANAGEMENT OF SOIL EROSION IN OMAN

The level of soil degradation worldwide is alarming due to its potential for causing serious problems such as threatening food security. The sultanate of Oman faces the problem of soil erosion which also disturbs waterways, infrastructure and agriculture. The problem of soil erosion has become increasingly apparent in Oman and is due to inappropriate land management. This occurs particularly with dams where sedimentation is a common issue and in the aflaj water systems. Currently, there are no appropriate methods being practiced that would overcome the problem of soil erosion in Oman, and no specific studies are available that discuss suitable methods for soil protection in Oman. Therefore, this study is an initiative to overcome the problem of soil erosion in Oman by proposing the best soil erosion protection method using the Analytic Hierarchy Process (AHP). In order to achieve this goal, this study reviews different methods of preventing soil erosion and the factors governing their selection. The important and controlling factors were considered in an AHP model to rank the soil erosion protection methods. Based on the AHP model, pairwise comparisons were conducted with the help of 15 experts from different sectors including authorities responsible for soil conservation in Oman, decision-making governmental departments and research institutes. The results of the AHP analysis indicated that the most suitable soil erosion protection method, based on the considered factors, is erosion control fences, followed by protection of the gully head and revetment. As no previous studies on suitable methods for soil conservation in Oman exist, this study bridges the gap by providing valuable information on the best soil protection methods that could help soil conservation authorities in Oman as they decide about possible future strategies.The study also indicated that the AHP model is a suitable guiding framework for decision-making because it involves a group of experts for the selection of soil protection methods based on the situation in Oman.