USLE Model Research Articles

Introduction pages, Nova Geodesia 4(3), 2024

Nova Geodesia (https://novageodesia.ro), Issue 3, Volume 4, 2024: The papers published in this issue represent interesting novelties in different topics of geodetic science or related fields. Nova Geodesia publishes significant papers in geodesy and close topics related to cartography, engineering projects and construction, planetology, hydrography, geography, sociodemographic factors, urban administration, planning and environment, landscape, biodiversity, and ecology. Among the exciting articles, we invite readers to find news about: Forest sampling techniques in different types of vegetation applying plot sampling, non-plot sampling, and remote sensing; Soil surface erosion susceptibility analysis using the USLE model. Case study: Bran - Dragoslavele Corridor, Romania; Feeding butterflies with Tridax procumbens (L.), a beneficial plant for maintaining butterfly populations; Impacts of climate-smart soil and water conservation practices and slope gradient on selected soil chemical properties in Eastern Ethiopia: A case study of the Kulkullessa Sub-watershed, Goro Gutu District; Comparative assessment of different rose cultivars under environmental conditions in central Transylvania, Romania; Plants associated with water towers in the Saharan environment: Floristic diversity and therapeutic virtues.

Soil Nutrient Inflow-Outflow Dynamics and Balance on Agricultural Cultivated Farms in Northern Ethiopia

Soil fertility is the controlling factor of agricultural production worldwide including Waghimera zone, Ethiopia. However, it has been diminished from time to time and leads to low crop yield. Measuring of soil nutrient inflow-outflow affords necessary information about the current nutrient status of the soils, and to take appropriate nutrient management practices. The study was conducted to estimate the full soil nutrient balance of cultivated farms in the northern, of Ethiopia, in the 2020/21 main season. Inflow and Outflow of N, P, and K into, and out of farms were measured through the interview, field measurement, laboratory analysis, USLE model, and pedo-transfer functions. The full N balance of barley, tef, and wheat were -66.7, -8.9, and -47.1 kg ha-1 yr-1, respectively. P full balance was -5.4, 1.4, and -1.9 kg ha-1 yr-1 for barley, tef, and wheat farms, respectively. Whereas, K balance was also -12.4, -3.3, and -6 kg ha-1 yr-1 for barley, tef, a nd wheat, respectively. The balance quantification was done by subtracting nutrient outflows from the inflows. The results revealed that N, P, and K had negative balances except for P in tef. Grain yield and crop residue removal were the major paths of nutrient loss. To sustain, and boost agricultural production, reversing the imbalance between inflows, and outflows is critically essential for the study area. The current highly depleted nutrient should be corrected by adding sufficient organic, and inorganic nutrient sources, like in situ manuring, biochar, green manure, and remaining crop residue in the fields.

English

Soil degradation is a global problem. Over the last several decades, the effects of land degradation in Tunisia are starting to have increasingly serious socio-economic and environmental repercussions. The agricultural sector is most seriously affected. The Tunisian Sahel, despite its modest topographical conditions, has not escaped this threat, especially upstream of the El Maasra Wadi. The fertile soils and homogeneous topography of this area, which dates to Roman times, are highly favorable to a wide range of agricultural practices. The Central Sahel has a long history of olive-growing, followed by a shift to irrigated farming in the 1970s. Today, it is given a multifunctional and multidimensional importance due to the complexity of conflicts of interest between different users. Rural abandonment, mining activity and pastoral pressure have all been behind the soil crisis, which is still largely unknown in detail in terms of the processes involved, the mechanisms behind them and the pace at which they are occurring. Today, there is an urgent need for tools and reliable methods to diagnose the state of soils, to elucidate the various facets of erosive processes and create the structural conditions necessary for their preservation. In the same vein, this research project was initiated in the Wadi El Maasra watershed to quantify soil losses using two methods: empirical model (USLE equation) and experimental based on the isotopic tracer of the Caesium-137. The two methods showed an almost identical geographical distribution, but slightly different loss rates. The specific soil loss obtained from the USLE model was of the order of 15 t ha-1 year-1, which appears to be largely underestimated compared with the loss rate obtained by the Caesium-137 method, which was of the order of 32 t ha-1 year-1.

Spatial Planning Decision Based on Geomorphic Natural Hazards Distribution Analysis in Cluj County, Romania

Spatial planning decisions form the basis of territorial progress by enhancing the resilience and opportunities for local and regional development. Therefore, decisions made as a result of multidisciplinary studies based on GIS assessment of all involved factors can provide a real and up-to-date image of the analyzed territory. In this context, geomorphic processes are among the factors restricting development, affecting built-up areas, transport infrastructure, and economic activities. This paper assesses geomorphic processes at the level of Cluj County, Romania, which mainly consist of active landslides that directly impact the accessibility of communities and their degree of safety, while accelerated soil erosion severely affects the output of land used for agriculture. GIS technology and a semi-quantitative model for determining the landslide hazard were used to classify landslides across occurrence probability classes. This methodology was implemented in Romania through Government Decision no. 447/2003. The USLE model was used to determine the soil erosion. As a result, the territory of Cluj County, which is the study area of this paper, was entirely included in one of the classes of risk concerning active geomorphic processes. Another important aspect consisted of categorizing transport infrastructure according to risk classes. A population risk assessment was also performed, taking into account the degree of accessibility of the territorial emergency department in the event that such hazards and processes occur. These results form the basis of proposals to efficiently plan the county territory, adapting decisions to the present trends in the evolution.

Calculation of the crop and crop menagment factor for assasment of potential erosion using usle model – case study Derenovac site, Paraćin

Calculation of the crop and crop menagment factor for assasment of potential erosion using usle model – case study Derenovac site, Paraćin

Potential Erosion in Mining, Oil Palm Plantations, and Watersheds Reforestation Areas

Erosion forecasting is a complex issue generated by numerous causes, the extent of which varies based on the unique area and conditions. Changes in rainfall, land cover, and watershed function are the primary causes of increased erosion. This study aims to scrutinize the actual and potential erosion in the mining area (MA), oil palm plantations (OPP), and watersheds reforestation (WR) in Asoloe, South Konawe, Indonesia. We utilized qualitative research methods and surveys with the USLE model. MA shares the highest actual erosion with 332.30 tons/ha/year, with an average erosion of 27.69 tons/ha/year from 2011 to 2022. Meanwhile, the potential erosion is 4747.19 tons/ha/year, with an average of 395.60 tons/ha/year. In terms of current conditions, 44.6% of rainfall engenders erosion with more than 0.5 t/ha and 33.9% with more than 1 t/ha. This study successfully demonstrates that for given location and area characteristics, high amounts of rainfall and changes in land function eminently affect soil erosion and that the potential erosion changes that occur in the Asoloe watershed every year are exceptionally influenced by changes in land use and land function. Therefore, some mitigation strategies and policies must be taken to reduce the risk of future erosion. Doi: 10.28991/CEJ-2023-09-09-07 Full Text: PDF

Assessment of carbon loss related to Soil loss in the tropical watershed of Maharashtra, India

Soil carbon pools have a significant impact on the global carbon cycle and soil erosion caused by natural or human activities is one of the main drivers of changes in soil carbon sequestration. The present study aimed to estimate the carbon loss associated with soil loss in the watershed using remote sensing and GIS techniques. The study was carried out at the Central MPKV Campus Watershed, Rahuri, located in the rain shadow region of the Maharashtra state, India. The soil loss from the watershed was estimated using USLE model. The soil loss and carbon loss from the watershed were estimated before the implementation of conservation measures and after the implementation of conservation measures. It was found that the average annual soil loss from the watershed before and after conservation measures was 18.68 t/ha/yr and 9.41 t/ha/yr, respectively. Carbon loss was determined by soil loss rate, organic carbon content and the carbon enrichment ratio. The carbon loss from the watershed before and after conservation measures was 348.71 kgC/ha/yr and 205.52 kgC/ha/yr. The findings revealed that soil and carbon erosion was very severe on steep slopes without conservation measures and with limited vegetation cover. It was found that by reducing the carbon loss associated with soil loss, soil conservation measures not only aid in the conservation of natural resources but also serve as a climate change mitigation measure.

Integrated use of GIS, RS and USLE model for LULC change analysis and soil erosion risk mapping in the Lake Hawassa Watershed, Southern Ethiopia

Soil erosion is a worldwide problem leading to loss of nutrient rich top soil resulting in reduction of agricultural productivity that threatens the livelihood of agrarian societies. Assessment of soil loss due to water-induced erosion using Models is essential to quantify and map erosion prone areas for possible application of soil conservation measures. In the current study, GIS, RS, and USLE model were integrated with the aim to quantify LULC classes, estimate soil loss rates, and identify priority areas for conservation in the Lake Hawassa Watershed for the two temporal instants, 1975 and 2020. The use of thematic recoding and model maker during LULC classification process has improved the accuracy of thematic classes, producing more than 89% for both classified images. The LULC change analysis showed that agricultural land and built-up area expanded by 0.44% and 15.26% per annum, respectively over the last 45 years. The declines in vegetation cover coupled with steep slopes have contributed to the increase in soil loss from 1975 to 2020 by 65%. The model estimated annual soil erosion rate in 1975 that ranged from nil to 158.77 t ha−1 yr−1 with a mean annual soil loss rate of 25.16 t ha−1 yr−1. Likewise, the annual soil loss estimated for the year 2020 varied from zero to 262.48 t ha−1 yr−1 with a mean annual soil loss rate of 28.20 t ha−1 yr−1. Generally, a total of 23,580.59 and 27,783.35 tons of soil have been lost per annum for the year 1975 and 2020, respectively, which is a direct reflection of vegetation clearance. The identified highest three severity classes combined accounted for 50.54% in 1975 and 55.40% of the entire soil loss in 2020 and these losses occurred on areas less than 2% in both 1975 and 2020 periods. Besides, 23.48% and 31.04% of soil loss rates exceeded the established tolerable limit of soil loss for the study area. The integrated use of USLE model, GIS and RS have identified erosion risk areas that could help apply conservation measures.

Trade-offs of multiple urban ecosystem services based on land-use scenarios in the Tumen River cross-border area

Land use change affected by rapid urbanization, economic development and political influences. As a crucial factor to ecosystem services (ESs), irrational land use is likely to bring about loss of some ecosystem services (ESs). In the meanwhile, the trade-offs occur among the ESs are also changing. This research aims to coordinate the relationship of ESs for land use planning under different scenarios in Tumen River Region. The essay has been organized in the following way. Initially, we analyzed the impact on 6 ESs in the context of the local land use change. Furthermore, we explored their trade-offs among the ESs and seek to provide theoretical support to planning and management in the Tumen River Region. Here, we used data from 1996 to 2006 and 2006–2016 to examine how the ecosystem services are affected by trade-offs in three different scenarios: Baseline Development (BD), Fast Development (FD), and Harmonious Development (HD) by using CASA and USLE models. Additionally, with the help of integrated valuation of ecosystem services and trade-offs (InVEST) model, we assessed 6 ecosystem services not only including Meat production (MP), Net primary production (NPP), Habitat quality (HQ), but Crop production (CP), Soil conservation (SC), Water retention (WR) as well during 1996–2016. Firstly, we demonstrated the numerous trade-offs and/or synergistic interactions between ESs. Then we assessed these ESs at the regional scale based on the 3 scenarios. Finally, we explored the optimal scenario. Results show that (1) it was significant that the dramatic land use change in the study area from 1996 to 2016, especially in cultivated land and forested land;(2) the total ESV in the study area initially decreased and then increased, and showed a gradual improvement trend during 1996–2016;(3) multiple ESs in addition to 2 ESs, containing Habitat Quality (HQ) and Soil Conservation (SC), there are also Water Retention (WR) and Net Primary Productivity (NPP) during 1996–2016 showed positive correlations. However, Crop and Meat Production vs Soil Retention was not significantly correlated in the study period;(4) among all scenario simulations, ESs showed the most improvement in the HD scenario, and following closely behind are the BD scenario and the FD scenario. The BD scenario had fewer trade-offs compared with against 2016, and the HD and FD scenarios had more;(5) relative to the catchment area, the HD scenario is the optimal situation. Our findings will provide some references for the construction of land use management and ecological civilization in cross-border area.

Response of soil erosion to vegetation restoration and terracing on the Loess Plateau

Soil erosion exhibited significant decrease due to the implementation of considerable soil and water conservation practices on the Loess Plateau, and further induced less sediment discharged into the Yellow River. However, the influences of these practices on soil erosion have not been comprehensively investigated over large-scale regions. This study analyzed spatiotemporal variation of vegetation cover, and identified the distribution of terraces by using Google Earth remote sensing images in the whole Loess Plateau. The USLE model (Universal Soil Loss Equation) was applied to estimate responses of soil erosion to vegetation restoration and terraces. The annual regional-averaged NDVI increased from of 0.46 in 2000 to 0.63 in 2018, suggesting significant vegetation improvement due to afforestation. We detected 4.73 × 104 km2 of terraces by 2018, which covered approximately 1.5% of the whole Loess Plateau. The terraces were mainly distributed in the upstream of the Weihe River, Fenhe, Zuli, Jinghe, and Taohe River basins. The validated soil erosion model showed that vegetation changes caused a remarkable reduction of 51.2% soil erosion from 2000 to 2018 across the Loess Plateau. A scenario modelling with terraces reduced 19.4% of soil erosion, indicating their significant effects on soil erosion controlling. This study could give a useful reference to assess soil erosion changes response to vegetation restoration and terrace at a large scale. The results can be used to optimize the spatial layout of the measures for soil erosion control in the Loess Plateau in the future.

Estimation of Erosion Potentials through Utilization of Remote Sensing Data and The Universal Soil Loss Equation Model

Remote sensing data and USLE models have been used widely for erosion analysis. In Indonesia, the USLE model is a reference in erosion analysis to assess land suitability for agricultural crop development. Erosion analysis using remote sensing data provides various advantages, including good accuracy, lower costs, and can analyze erosion rates quickly compared to direct measurement methods. The aim of this study was to analyze the potential erosion in the Arui watershed - Manokwari Regency – West Papua Province using remote sensing data and USLE models. The research was conducted from April to July 2022, with three main stages i.e data inventory, data analysis, and erosion rate estimation. The research shows that the potential erosion rate in the Arui watershed is 15 tons/ha/year or 3.480 tons/year, thus exceeding the tolerable soil loss (TSL) erosion rate threshold of 9.6 tons/ha/year. Therefore, a conservation and restoration program is needed to control the erosion rate in the Arui watershed. Keywords: Erosion rate, Remote sensing, Tolerable soil loss, USLE, Watershed

Study on the relationship between topological characteristics of ecological spatial network and soil conservation function in southeastern Tibet, China

Many regions on the globe are at risk of soil erosion, especially in the ecologically fragile areas of the Qinghai-Tibet Plateau. Enhancing the soil conservation capacity of regional vegetation is one of the main ways to address soil erosion. However, most studies ignore the relationship between the spatial distribution structure of vegetation and soil conservation capacity, and the construction of ecological spatial networks is an effective means to study the spatial distribution structure of vegetation. In this study, we extracted the ecological spatial network of Southeast Tibet by the minimum resistance model (MCR) and combined the ecological network with complex network theory to calculate the topological indices of the ecological spatial network and ecological nodes. Subsequently, the soil conservation capacity of ecological nodes is calculated based on the USLE model, and the relationship between it and topological indices is analyzed. It was shown that the degree, closeness centrality, betweenness centrality and eigenvector centrality of forest nodes showed a positive linear correlation with their soil conservation capacity, and the clustering coefficient of grassland nodes showed a positive linear correlation with their soil conservation capacity. This study calculates habitat quality based on the Invest model. We propose a Integrated Soil Conservation and Habitat Quality Evaluation (ISHE) Model to determine the direction of network optimization and propose an optimization strategy. We analyze the network robustness and soil conservation capacity and find that the optimized network robustness and soil conservation capacity are significantly improved. This study provides strategies and methods to protect ecologically vulnerable areas, optimize the spatial distribution of vegetation, and enhance soil conservation capacity. In addition, this can provide a theoretical reference for planning national ecological projects. We use the ISHE model to filter out three types of nodes that need to be focused on optimization and propose different optimization strategies.

Forecasting Erosion Induced Landslide Risk Level in Cameron Highlands Towards Environmental Sustainability

The Cameron Highlands are particularly susceptible to erosion because of their agricultural and urban expansion. Numerous existing and proposed development projects in the Cameron Highlands have contributed to this scenario which risks the environment. Thus, this study uses the USLE model with a GIS application to assess the risk of soil loss in Cameron Highlands. An earlier study by PLANMalaysia and the Department of Agriculture Malaysia, which documented varying land use and land cover, yielded different soil loss risk estimates in the Cameron Highlands. Town growth and development are reflected in land-use statistics from PLANMalaysia, whilst agricultural influence is reflected in land-use data from the Department of Agriculture. Based on the findings, REDAC USM's soil loss risk level estimated that 6.72 per cent of the Cameron Highlands have a 'HIGH' risk or higher. With the use of this new soil loss risk level developed by REDAC USM, farmers and local authorities may be able to regulate present land-use habits, reduce soil loss and erosion, and promote environmental sustainability in the Cameron Highlands.

Soil Loss Estimation Coupling a Modified USLE Model with a Runoff Correction Factor Based on Rainfall and Satellite Soil Moisture Data

Satellite observations (Copernicus Sentinell-1) can supply antecedent soil moisture data, which helps to predict thresholds triggering runoff and runoff volume. In the paper, we developed a runoff correction factor to the USLE, using rainfall and satellite antecedent soil moisture data, following the approach of the modified USLE models such as the USLE-M and USLE-MM. The runoff and soil loss estimations accuracy are validated by plot-scale measurements (2008–2020 period) provided by SERLAB (Soil Erosion Laboratory) of the University of Perugia. The results show that the event rainfall depth added to the antecedent soil moisture is a fairly suitable predictor of the runoff. Using the simulated runoff in a USLE-MM model, the capability to predict event soil losses is enhanced with an RMSE = 0.57 Mg/ha lower than the RMSE ≈ 3.1 Mg/ha obtained by the USLE model. Using a modified USLE model, albeit with remote estimated runoff data, is still more advantageous at the event scale than the USLE model, which does not consider the runoff. These results are particularly significant for the estimation of runoff and soil losses. Satellite data shows the potential of applying the modified USLE models for large-scale monitoring and quantification of event soil erosion and runoff.

Prediction of Erosion-Prone Areas in the Catchments of Big Lowland Rivers: Implementation of Maximum Entropy Modelling—Using the Example of the Lower Vistula River (Poland)

It is common knowledge that erosion depends on environmental factors modified by human activity. Erosion within a catchment area can be defined by local lithological, morphometric, hydrological features, etc., and land cover, with spatial distribution described by means of remote sensing tools. The study relied on spatial data for the catchment of the Lower Vistula—the biggest river in Poland. GIS (SAGA, QGIS) tools were used to designate the spatial distribution of independent environmental variables that determined the process of erosion according to land cover types within the Lower Vistula catchment (Corine Land Cover). In addition, soil loss in the catchment area was calculated using the USLE model (Universal Soil Loss Equation). The spatial data was used to determine the predictive power of variables for the process of erosion by applying the maximum entropy model (MaxEnt) commonly used in fields of science unrelated to fluvial hydrology. The results of the study pointed directly to environmental features strongly connected with the process of erosion, identifying areas susceptible to intensified erosion, and in addition positively verified by USLE. This testifies to the correct selection of the proposed method, which is a strong point of the presented study. The proposed interdisciplinary approach to predict erosion within the catchment area (MaxEnt), widely supported by GIS tools, will allow the identification of environmental pressures to support the decision-making process in erosion-prone areas.

Estimation of soil erosion in loess plateau based on geographic information system

One of the core problems in soil erosion research is the estimation of soil erosion. It is a feasible method and technical approach to estimate soil erosion in Loess Plateau region by using USLE model, GIS and RS technology and using DEM data, meteorological data and land-use type data. With the support of GIS and RS technology, the USLE factors and soil erosion in Loess Plateau region were estimated, and the soil erosion intensity was classified according to the Chinese soil erosion intensity classification standard. The results can provide reference for the development of soil erosion control measures in the Loess Plateau.

Soil erosion prediction using USLE model in Cangkringan micro watershed model, Yogyakarta

Land use that is not in accordance with ecological principles causes’ excessive soil erosion. Soil erosion has an impact on decreasing soil productivity, increasing critical land and causing land degradation. It is essential to predict the amount of soil lost due to soil erosion to determine the conservation efforts applied to suppress the erosion rate. The estimation of erosion in this study using the USLE model, using 5 factors, namely erosivity (R), erodibility (K), slope length (LS), crop management (C), and soil conservation (P). The results showed that the level of erosion hazard in Cangkringan Micro Watershed Model consisted of 5, namely very light covering an area of 29.14 ha (2.15%), mild covering an area of 642.31 ha (47.44%), moderate covering an area of 545.62 ha (40.30%), heavy area of 129.00 ha (9.53%) and very heavy area of 7.94 ha (0.58%).

GIS-BASED WATER EROSION MODELLING: THE CASE OF HIGH SLOPE WATER CATCHMENT AREA, ROMANIA

This paper shows the results of a series of hydrographic simulations by mathematical modelling of the erosion phenomenon. The main goal is to show the importance of using the GIS technique to analyse the erosion process. Our research uses several well-known mathematical models and GIS software. Mathematical modelling was performed with the USLE model running under Geo-Graph software and the WEPP model running under ArcGIS 9.2 software. The multitude of factors involved in modelling and especially their spatialization is the main argument for choosing these two models. Finally, in order to be able to compare the results, in both cases the erosion simulation was conducted in the same hydrographic area, under the same geographical, climatic, pedological and relief conditions. The research focuses on a location with steep slopes affected by significant soil degradation processes. This paper used five input parameters in the simulation process using the USLE model: daily weather forecasting, vegetation or food growing management, land and soil topography. The model is based on daily regulates the hydrological state of the tested soils. Since climate change has had a major impact on soil erosion, the WEEP model has proven to be an efficient tool in erosion modelling, as it allows the entry of a large set of climate data. The WEEP model has also been used worldwide due to its ability to accept a multitude of data sets of soil characteristics. In the present case, in our research, the USLE model was used first, being launched before WEEP, as it has been used worldwide, but the results obtained with the WEEP model were good in almost all our simulations. The main results of this phase of our research show that the erosion is significant and exceeds acceptable limits. Therefore, in conclusion, major support practice actions and an appropriate agricultural practice are recommended to mitigate the effects of erosion process.

Establishment and application of soil hydraulic erosion model based on GIS and USLE model

Soil erosion is the most common form of soil degradation, which is the main problem of soil environmental destruction worldwide. Based on the USLE and GIS remote sensing inversion and superposition analysis technology, this study simulated and calculated soil hydraulic erosion in Fangshan World Geological Park, China in 2011, 2012 and 2013, analyzed its spatial-temporal dynamic changes, and explored the key points of soil erosion control in the study area. The results show that (1) The main erosion occurred at 25°-35° steep slope and 400-800m height, which accounted for more than 30% of the total soil erosion in all the three years. (2) The average erosion modulus and erosion amount in 2012 were significant higher than that in 2011 and 2013 at each slope grade, shown that the soil erosion of 2012 is influenced by natural disaster.With the increase of slope grade, the average modulus also increased.

Assessment of the soil loss-prone zones using the USLE model in northeastern Iran

This research attempted to evaluate the soil loss-prone zones and affecting key factors in a suburb agricultural area in the western Mashhad city, northeastern Iran, using the universal soil loss equation model. All erosion factors and components were produced in GIS grid-based modeling. Therefore, the required data, such as topography, climate, and soil characteristics, were collected from global databases. The estimated annual soil loss values were classified into five classes from slight soil losses (0–3 t ha−1 year−1) at the plain lowland in the northern region to severe soil losses (25–55 t ha−1 year−1) at the hillsides and terraces in the middle part of the study area. The results revealed that about 9.36% of the study area (6743 km2) is under critical erosion-prone zones of high and severe soil losses (over 15 t ha−1 year−1). Ultimately, the relationships between soil loss-prone zones and soil taxonomy order/sub-orders were investigated to prevalence the results in the other alike geo-climatic status. Correlation analysis conveniently confirmed a very strong, significant, and direct relationship (R equal to 0.997) between high/severe soil losses and xerolls in the study area at the 95% confidence level. In the study area, the most soil loss and sedimentation were predicted for xerolls soil sub-order (mollisols) with 5.5 t ha−1 year−1 and 14.69 million t year−1 (over 60% of total sedimentations).