Soil Erosion Survey Research Articles

Spatial Quantification of Cropland Soil Erosion Dynamics in the Yunnan Plateau Based on Sampling Survey and Multi-Source LUCC Data

The mapping and dynamic monitoring of large-scale cropland erosion rates are critical for agricultural planning but extremely challenging. In this study, using field investigation data collected from 20,155 land parcels in 2817 sample units in the National Soil Erosion Survey, as well as land use change data for two decades from the National Land Use/Cover Database of China (NLUD-C), we proposed a new point-to-surface approach to quantitatively assess long-term cropland erosion based on the CSLE model and non-homologous data voting. The results show that cropland in Yunnan suffers from serious problems, with an unsustainable mean soil erosion rate of 40.47 t/(ha·a) and an erosion ratio of 70.11%, which are significantly higher than those of other land types. Engineering control measures (ECMS) have a profound impact on reducing soil erosion; the soil erosion rates of cropland with and without ECMs differ more than five-fold. Over the past two decades, the cropland area in Yunnan has continued to decrease, with a net reduction of 7461.83 km2 and a ratio of −10.55%, causing a corresponding 0.32 × 108 t (12.12%) reduction in cropland soil loss. We also quantified the impact of different LUCC scenarios on cropland erosion, and extraordinarily high variability was found in soil loss in different basins and periods. Conversion from cropland to forest contributes the most to cropland erosion reduction, while conversion from grassland to cropland contributes 56.18% of the increase in soil erosion. Considering the current speed of cropland regulation, it is the sharp reduction in land area that leads to cropland erosion reduction rather than treatments. The choice between the Grain for Green Policy and Cropland Protecting Strategy in mountainous areas should be made carefully, with understanding and collaboration between different roles.

Geomorphic factors influencing the spatial distribution of eroded Chernozems in automated digital soil erosion mapping

Among the factors influencing the intensity of soil erosion by water, the relief sets the basic conditions for the occurrence of erosion-sedimentation processes: the geometry of the contact surface with water runoff and its primary spatial characteristics. We developed a model that describes the categories of the intensity of soil erosion by water only by geomorphic parameters using a DEM. The study was conducted in arable soils in the southeastern part of the Central Russian Upland, namely, typical Chernozems (TCh) in the forest-steppe zone and ordinary Chernozems (OCh) of the northern steppe of the temperate climate zone. Based on 1146 ground soil-erosion survey points, the relationship between the category of soil erosion intensity and terrain parameters (slope steepness, slope length and exposure, topographic position index, and slope profile curvature, etc.) was analyzed. The results of the revealed dependencies for the studied soils made it possible to develop prognostic models using ordinal logistic regression with an assessment of their accuracy. It was found that the model for OCh soils shows in all parameters a stronger relationship between geomorphic factors and the category of soil erosion intensity than the model for TCh soils. The regression model for OCh exceeds the model for TCh by 12 % in overall accuracy. For both soils, eroded areas are determined with much less accuracy (50–60 %) than non-eroded areas (80–95 %). Based on the modeling results, maps of soil erosion by water were constructed, where belonging to the category of soil erosion intensity was determined by the maximum probability. It is also shown that soil erosion intensity modeling based only on a set of geomorphic predictors is not inferior in accuracy to the conventional visual-expert cartographic method and can be a more objective and efficient alternative in automated digital soil erosion mapping.

Comparison and quantitative assessment of two regional soil erosion survey approaches

Regional soil erosion surveys are the first step of soil conservation planning. Grid and sampling approaches are commonly used for soil erosion surveys at the regional scale. With the grid approach, the region is divided into grids (e.g., 1 km × 1 km), and the soil erosion rate of each grid was calculated. With the sampling approach, a small portion of the area (typically 4% or less) was taken and then the soil erosion rate was calculated. Based on the above calculation, both approaches evaluated the soil erosion area (which is the area where the soil erosion rate is greater than the soil loss tolerance (t)) and its distribution in the whole region. The purpose of this paper is to compare the assessment results of the two approaches and analyse their practicality using Yunyang County, Chongqing, China (area is 3636 km2). The soil erosion rate, percentage of soil erosion area (PSEA, which is the ratio of the area where the soil erosion rate is greater than the soil loss tolerance (t) to the area of the total study region) and its spatial distribution were compared between the two approaches. The results showed that the grid approach overestimated the average soil erosion rate and PSEA overall for all 33 sample units and the whole region in comparison to the sampling approach. The sampling approach can yield a reasonable spatial distribution of the soil erosion rate in the whole region. In addition, the soil erosion regions were more clustered than those using the grid approach, which can be more suitable for soil conservation planning. Therefore, the sampling approach is an efficient and practical approach in regional soil erosion surveys. The results can provide insights into regional soil erosion surveys.

Application of geoinformation systems for a complex analysis of data from agrochemical and soil-erosion monitoring of soils

The article describes the development of a geoinformation system module (using the example of GIS “Agroecologist Online”) to automate the complex analysis of agrochemical and soil-erosion monitoring data. With the help of an additional GIS module, it allows you to generate reports with tabular data of various groupings: by soil type and degree of erosion; by soil type and slope steepness; by soil type, degree of erosion and exposure; by soil type, slope steepness and exposure; by soil type, degree of erosion, slope steepness and exposure. Based on the presented tables, using the module, it is possible to analyze the indicators of agrochemical and soil-erosion survey in a comprehensive manner. The module also allows you to predict the level of yield of certain crops, to timely identify the deterioration of soil resources for a certain territorial unit (within a specific farm, a specific region, as well as on the territory of the entire Russian Federation).

Изменение поглотительной способности почв по элементам рельефа балочных водосборов ЦЧР

Работа посвящена изучению особенностей состава почвенного поглощающего комплекса (ППК) по элементам рельефа балочного водосбора. Целью работы является выявление зависимости ППК от степени развития и характера водной эрозии и аккумуляции. Для достижения поставленной цели был решен ряд задач: проведение площадной почвенно-эрозионной съемки балочного водосбора; определение физико-химических и физических свойств почв по ГОСТированным и общепринятым методикам; сравнительный анализ поглотительных свойств почв по элементам рельефа балочного водосбора. Высокая степень эродированности территории определяет актуальность исследования поглотительных свойств почв, подверженных смыву и намыву. Объектом исследования являются почвы водосборной площади балки «Лог Репный». Согласно почвенно-эрозионному районированию Воронежской области объект исследования расположен в Семилукско-Нижнедевицком районе. Наблюдалось обеднение всего профиля почв водораздельных склонов и берега балки илистой фракцией за счет влияния эрозии почв и денудации. На днище балки было зафиксировано обогащение верхней части почвенного профиля илистой фракцией под влиянием аккумуляции почвенного материала, смываемого с вышележащих склонов. Поглотительная способность почв различных элементов рельефа водосборной площади балки «Лог Репный» может быть охарактеризована с помощью величины суммы поглощенных оснований. Наибольшая сумма поглощенных оснований наблюдалась на водораздельном плато (15.73 ммоль/100 г почвы). На берегу балки в условиях влияния процесса денудации зафиксировано уменьшение суммы поглощенных оснований в 2.5 раза. На днище балки в зоне преимущественной аккумуляции смываемого со склонов почвенного материала сумма поглощенных оснований была ниже, чем на водоразделе в 1.4 раза. Это связано с различным содержанием илистой фракции в этих почвах. Так, в почвах водоразделов илистая фракция составляла 24.8%, на берегу балки ее содержание было в 2.5 раза ниже, а на днище балки вновь возрастало до 22.4 %. Установлена зависимость суммы поглощенных оснований почв от перераспределения илистой фракции под влиянием эрозии и аккумуляции почв.

The assessment of soil loss by water erosion in China

Soil erosion is a major environmental problem in China. Planning for soil erosion control requires accurate soil erosion rate and spatial distribution information. The aim of this article is to present the methods and results of the national soil erosion survey of China completed in 2011. A multi-stage, unequal probability, systematic area sampling method was employed. A total of 32,948 sample units, which were either 0.2–3 km2 small catchments or 1 km2 grids, were investigated on site. Soil erosion rates were calculated with the Chinese Soil Loss Equation in 10 m by 10 m grids for each sample unit, along with the area of soil loss exceeding the soil loss tolerance and the proportion of area in excess of soil loss tolerance relative to the total land area of the sample units. Maps were created by using a spatial interpolation method at national, river basin, and provincial scales. Results showed that the calculated average soil erosion rate was 5 t ha−1 yr−1 in China, and was 18.2 t ha−1 yr−1 for sloped, cultivated cropland. Intensive soil erosion occurred on cropland, overgrazing grassland, and sparsely forested land. The proportions of soil loss tolerance exceedance areas of sample units were interpolated through the country in 250 m grids. The national average ratio was 13.5%, which represents the area of land in China that requires the implementation of soil conservation practices. These survey results and the maps provide the basic information for national conservation planning and policymaking.

Quantitative Assessment of Soil Erosion Based on CSLE and the 2010 National Soil Erosion Survey at Regional Scale in Yunnan Province of China

Regional soil loss assessment is the critical method of incorporating soil erosion into decision-making associated with land resources management and soil conservation planning. However, data availability has limited its application for mountainous areas. To obtain a clear understanding of soil erosion in Yunnan, a pixel-based estimation was employed to quantify soil erosion rate and the benefits of soil conservation measures based on Chinese Soil Loss Equation (CSLE) and data collected in the national soil erosion survey. Results showed that 38.77% of the land was being eroded at an erosion rate higher than the soil loss tolerance, the average soil erosion rate was found to be 12.46 t∙ha−1∙yr−1, resulting in a total soil loss of 0.47 Gt annually. Higher erosion rates mostly occurred in the downstream areas of the major rivers as compared to upstream areas, especially for the southwest agricultural regions. Rain-fed cropland suffered the most severe soil erosion, with a mean erosion rate of 47.69 t∙ha−1∙yr−1 and an erosion ratio of 64.24%. Lands with a permanent cover (forest, shrub, and grassland) were mostly characterized by erosion rates an order of magnitude lower than those from rain-fed cropland, except for erosion from sparse woods, which was noticeable and should not be underestimated. Soil loss from arable land, woodland and grassland accounted for 52.24%, 35.65% and 11.71% of the total soil loss, respectively. We also found significant regional differences in erosion rates and a close relationship between erosion and soil conservation measures adopted. The CSLE estimates did not compare well with qualitative estimates from the National Soil Erosion Database of China (NSED-C) and only 47.77% of the territory fell within the same erosion intensity for the two approaches. However, the CSLE estimates were consistent with the results from a national survey and local assessments under experimental plots. By advocating of soil conservation measures and converting slope cropland into grass/forest and terraced field, policy interventions during 2006–2010 have reduced soil erosion on rain-fed cropland by 20% in soil erosion rate and 32% in total soil loss compared to the local assessments. The quantitative CSLE method provides a reliable estimation, due to the consideration of erosion control measures and is potentially transferable to other mountainous areas as a robust approach for rapid assessment of sheet and rill erosion.

Trends of Soil Processes in Natural Landscapes of Mountain and Piedmont Provinces of Dagestan

Data of long-term researches for revealing the trend of modern processes of soil formation and degradation in the mountain and piedmont provinces of Dagestan are given. The aim of the researches was to study the modern soil-erosion and ecologic-ameliorative status of the soil cover and changes in the naturalresource potential of slope lands under the effect of natural and anthropogenic factors over a 50-year period. A strong effect of exogenic and endogenic factors on slope ecosystems results in development of erosion and degradation processes. The soil cover is formed under conditions of intensive geomorphologic, geochemical, and biological processes. The increasing anthropogenic load and climate aridization exert a strong effect on their dynamics. The comparison of data of earlier soil-erosion survey with modern ones shows great changes in the spatial pattern of eroded soils. The areas of noneroded lands became two times smaller over the period of studies. There is a tendency for a decrease in the areas of brown forest soils of a hydromorphic type of soil formation and for enlargement in the area of semihydromorphic and automorphic brown and chestnut soils. A great diversity of soil–plant cover in the areas with vertical zonality is related to differences in slope aspects, topography, and steepness. Soil evolution is characterized by a trend from hydromorphic and semihydromorphic to automorphic stages of soil formation.

The CSLE model based soil erosion prediction: Comparisons of sampling density and extrapolation method at the county level

The Universal Soil Loss Equation (USLE) is an empirical equation commonly applied to predict soil erosion throughout the world. In China, the Chinese Soil Loss Equation (CSLE) has been developed for estimating annual soil erosion by water on the basis of the USLE. It is proven that two factors (i.e., sampling density and extrapolation method) are important in the application of CSLE for soil erosion survey and evaluation. In this study, based on the SPOT 6 image (1.5 m resolution) and the 1:10,000 topographic map in Yishui county of the Yimeng Mountain Area (YMA), eastern China, two sampling densities (1% and 4%) were selected and three extrapolation methods (grid based calculation, direct extrapolation, and Kriging extrapolation based on sampling units) were adopted to compare their effect on the CSLE calculated soil erosion condition and status. Results showed that estimated soil erosion by direct extrapolation and Kriging extrapolation methods varies largely with sampling density. The discrepancy of the soil erosion area ratios calculated by the two methods are 6.5% and 7.7% under the 1% and 4% sampling density, and the relative discrepancies are 15.9% and 16.2%, respectively. But the grid calculation method is less affected by sampling density. The discrepancy of soil erosion area ratios is only 0.9% and 2.0%, respectively, under the 1% with 4% sampling density. Considering both field workload and prediction accuracy of soil erosion, the 1% sampling density with the grid calculation method is recommended when high resolution remotely sensed data are available. Otherwise, the 4% sampling density with either extrapolation method should be used. The research can provide useful reference information for ensuring the accuracy and reducing the survey workload on the application of CSLE in other areas.

Environmental effectiveness of GAEC cross-compliance Standard 1.1a (temporary ditches) and 1.2g (permanent grass cover of set-aside) in reducing soil erosion and economic evaluation of the competitiveness gap for farmers

This paper shows the results of the monitoring carried out in three hilly farms of the MONACO project in order to verify the effectiveness of the Standard 1.1 (commitment a) (temporary ditches) and Standard 1.2 (commitment g) (Vegetation cover throughout the year in set-aside land) in the reduction in soil erosion, contained in Rule 1: ‘minimum land management that meets specific conditions’ of the decree Mipaaf 2009 and following modifications, until the recent decree No. 180 of January 23, 2015. In addition, the assessment of the competitiveness gap was done. That is the evaluation of the additional costs borne by the beneficiary of the single payment determined from agronomic commitments. Monitoring has also compared the erosion actually observed in the field with that predicted by RUSLE model (Revised Universal Soil Loss Equation) (Renard et al., 1997) in the two situations: with and without the presence of temporary ditches, i.e. assuming Factual (compliance rules) and in that Counterfactual (infringement). This comparison was made in view of the fact that the RUSLE model was chosen by the 'European Evaluation Network for Rural Development (EEN, 2013) as a forecasting tool for the quantification of' Common Indicator ‘soil erosion by water’. The results of soil erosion survey carried out by using a new UAV-GIS methodology on two monitoring farms in two years of observations have shown that temporary ditches were effective in decreasing erosion, on average, by 42.5%, from 36. 59 t ha-1 to 21.05 t ha-1 during the monitoring period. It was also evaluated the effectiveness of grass strips (at variance with the commitment of temporary ditches). The results showed a strong, highly significant, reduction in erosion by about 35% times respect soil erosion observed in bare soil and also a significant reduction in the volume of runoff water.  With regard to Standard 1.2 (commitment g) the statistical analysis shows a strong and highly significant decrease in the erosion due to the vegetation cover of the soil compared to bare soil. The economic competitiveness gap of Standard 1.1(commitment a) stood at € 4.07±1.42 € ha-1 year-1, while CO2 emissions due to execution of temporary ditches was 2.58 kg ha-1year-1. As for the Standard 1.2 (commitment g) the average differential competitiveness gap amounted to 50.22±13.7 € ha-1 year-1 and an output of CO2 equal to 31.52 kg ha-1 year.

Characteristics of water erosion and conservation practice in arid regions of Central Asia: Xinjiang, China as an example

Located in the inland arid area of Central Asia and northwest China, Xinjiang has recently received heightened concerns over soil water erosion, which is highly related with the sustainable utilization of barren soil and limited water resources. Data from the national soil erosion survey of China (1985–2011) and Xinjiang statistical yearbook (2000–2010) was used to analyze the trend, intensity, and serious soil water erosion regions. Results showed that the water erosion area in Xinjiang was 87.6×103km2 in 2011, mainly distributed in the Ili river valley and the northern and southern Tian Mountain. Soil erosion gradient was generally slight and the average erosion modulus was 2184t/(km2a). During the last 26 years, the water erosion area in Xinjiang decreased by 23.2%, whereas the intensity was still increasing. The driving factors from large to small impact included: population boom and human activities>vegetation degradation>rainfall and climate change>topography and soil erodibility>tectonics movement. Soil water erosion resulted in eco-environmental and socioeconomic losses, such as destroying farmland and grassland, triggering floods, sedimentation of reservoirs, damaging transportation and irrigation facilities, and aggravating poverty. A landscape ecological design approach is suggested for integrated control of soil erosion. Currently, an average of 2.07×103km2 of formerly eroded area is conserved each year. This study highlighted the importance and longevity of soil and water conservation efforts in Xinjiang, and offered some suggestions on ecological restoration and combating desertification in arid regions of Central Asia.

Organic carbon stocks and erosion in the soils of Guangdong, South China

Soil organic carbon (SOC) storage and erosion in South China at the regional scale in the past decades remains far from being understood. This paper calculated the SOC density, storage and erosion in 14 soil classes in Guangdong Province, South China, based on statistical data from the soil survey and soil erosion survey of Guangdong, which was performed in the 1990s. The purpose of this study is to understand the relationships between soil classes and SOC erosion at the regional scale. The results indicated that the SOC density in the soils of Guangdong varied from 12.7 to 144.9 Mg ha−1 over the entire profile and from 12.6 to 68.4 Mg ha−1 in the top 20-cm soil layer. The average area-weighted SOC density in the topsoil (0–20 cm) and the entire profile was 32 ± 3 and 86 ± 4 Mg ha−1, respectively. The total SOC storage was 1.27 ± 0.06 Pg, with 35.6 % (0.46 ± 0.04 Pg) located in the topsoil. The average area-weighted strength of the SOC erosion in the 1990s was 20.6 ± 0.8 Mg km−2 year−1. The results indicated that SOC erosion was strongly related to soil class.

Soil Erosion and Preventive Measures in the 3<sup>rd</sup> Expansion Project of Xiaolongtan Power-Station

Based on the regional topography, engineering geology, hydrology, vegetation, soil, and soil erosion survey of Xiaolongtan power plant, this paper will analyze the area of influence according to the soil and water loss and its effects in this project, and according to the characteristics of construction projects and the local natural conditions, combined with the characteristics of soil and water loss control degree of each region and the affected, The biological measures with engineering measures together, take slag retaining engineering, drainage engineering, land consolidation engineering and plant measures for the comprehensive management.So the effect of soil erosion will be reduced to minimum level, the area of new erosion will be effectively controlled. And this will provide guarantees for the security run of the power plant, protect and improve environment quality in and around the project construction area.

Research on Sensitivity for Soil Erosion evaluation from DEM and Remote Sensing Data source of Different Map Scales and Image Resolutions

Abstract Current evaluation on soil erosion in the scale of watershed mostly use the different scale DEM (Digital Evaluation Model) datas and different resolution remote sensing images without considering their sensitivity for soil erosion evaluation. In this study, three different scale DEM maps of 1:50 000,1:100 000 and 1:250 000 and two different resolution remote sensing images in a same watershed are used to study their sensitivity for soil erosion evaluation in the method of multi-factors space superposed assessment which was the main method for the second soil erosion survey of China. Results show that: 1) With the smaller scale DEM data, there are bigger area in the small slope range calculated from the DEM maps, the information from the small scale DEM just represent macroscopically terrain. 2) The graded soil erosion area changes from three DEM data have same trends, the percentage of soil erosion area calculated from small scale DEM data is bigger than that from the big scale DEM data in the slight and light erosion intensity range, but there are reverse results above the light erosion intensity range. 3) Different scale DEM data affects the calculation of the erosion amount. The calculated erosion amount is greater with the bigger scale DEM data source. 4) The change trend of area of different land-use types interpreted from 30 meters LANDSAT TM image and 10 meters SPOT image is same. They embody the same land-use patterns in the watershed. The high resolution image has greater interpretation accuracy, and the vegetation coverage taken from two resolution images have same change trend. The vegetation coverage was affected by the obtaining time of remote sensing image.

Soil erosion in China based on the 2000 national remote sensing survey

This paper discussed the spatial distribution of soil erosion in China at the end of the 20th century based on the second national soil erosion survey. The result indicated soil erosion is still the prime environmental problem in China. Soil erosion mainly occurs in the western regions of China, and the slight erosion type, ion the whole, exerts the greatest impact on soil erosion pattern. The distribution of water erosion shows the impact of landforms: slight water erosion mainly in mountainous and hilly areas, and half of violent water erosion on the loess landforms. Farmland, forestland and grassland are the major land use types of slight hydraulic erosion distribution, while the serious hydraulic erosion and slight wind erosion mainly occur on grassland. Thus, the conservation of the grassland is the key to either hydraulic and wind erosion control. The huangmian soil (a major type of cultivated soil developed from loess mother material) is the one facing the most serious threat from soil erosion in Chinas soil resources. Further discussion on the soil erosion distribution still needs more research on the method and relevant data analysis.

Soil erosion survey of the central part of the Swaziland Middleveld

Soil erosion has worsened considerably in the Middleveld of Swaziland over the last 20 years. Most of the erosion has occurred on deep colluvial and saprolitic materials and is associated with convex-slope breaks and rejuvenation shoulders on valley sides. Although the risk of erosion seems to reflect natural instability in the landscape, the way in which the land is used determines the ultimate severity of the problem. Land systems can serve as functional units as far as erosion assessment is concerned. The most severely eroded land occurs within the Manzini, Jabuleni, Lobamba and Chibidze land systems. The universal soil loss equation (USLE) and the soil loss estimator for southern Africa (SLEMSA) give vastly different estimates of the rate of soil loss but no information is available to validate or refute the predictions.

A Technique for Local Soil Erosion Survey

Abstract A procedure for erosion assessment representation by symbols, using aerial photography, is required for use at the local scale. This scheme (employing 1:10 000 scale orthophotomaps as a base) was developed within the Bethlehem Runoff Augmentation Research (BRAR) project as a preliminary to hydrological modelling for investigating changes in soil erosion rates. A full legend of the symbols, as well as a description of their relevance to erosion assessment is discussed. As overlays onto the orthophoto base-map, the graphic erosion data and a simple slope classification were found to be of use in defining erosion sensitive areas. Present soil erosion activity and localities that may be prone to a high erosion potential could be identified with a view to selecting experimental and monitoring sites. The suggested sequence of survey procedure is outlined and a list of potential uses for the map is proposed besides that for which it was initially designed. These range from detailed specific collection of data through regional land capability assessments to forming a part of a nationwide survey, such as that proposed by SARCCUS.

Soil Erosion Survey in Southeastern States

Soil Erosion Survey in Southeastern States