Estimation and mapping of water erosion and soil loss:Application of Gavrilovic erosion potential model(EPM)using GIS and remote sensing in the Assif el mal Watershed,Western high Atlas

Water erosion is a serious problem that leads to soil degradation,loss,and the destruction of structures.Assessing the risk of erosion and determining the affected areas has become crucial in order to understand the main factors influencing its evolution and to minimize its impacts.This study focuses on evaluating the risk of erosion in the Assif el mal watershed,which is located in the High Atlas Mountains.The Erosion Potential Model(EPM)is used to estimate soil losses depending on various parameters such as lithology,hydrology,topography,and morphometry.Geographic information systems and remote sensing techniques are employed to map areas with high erosive potential and their relationship with the distribution of factors involved.Different digital elevation models are also used in this study to highlight the impact of data quality on the accuracy of the results.The findings reveal that approximately 59%of the total area in the Assif el mal basin has low to very low potential for soil losses,while 22%is moderately affected and 19.9%is at high to very high risk.It is therefore crucial to implement soil conservation measures to mitigate and prevent erosion risks.

Dynamics of Soil Erosion in Xingguo County, China, Determined Using Remote Sensing and GIS

The spatial and temporal dynamics of soil erosion in Xingguo County, Jiangxi Province, China were studied using multi-period remote sensing images and GIS. The results indicated that the soil erosion status of the region has been improving, particularly since the 1980s, with the erosion rate showing an evident decline over the past 30 years. The improvement showed not only in the decline of eroded soil area, but also with the reduction in the extent of erosion. The extent of erosion mainly changed by one level, and the change primarily occurred with the severely or moderately eroded soil types. However, in general, soil erosion was still an overriding problem in the region with some areas becoming more serious, especially those with large quantities of granite.

Assessment of soil erosion by RUSLE model using remote sensing and GIS-A case study of Nethravathi Basin

Soil erosion is a serious problem arising from agricultural intensification, land degradation and other anthropogenic activities. Assessment of soil erosion is useful in planning and conservation works in a watershed or basin. Modelling can provide a quantitative and consistent approach to estimate soil erosion and sediment yield under a wide range of conditions. In the present study, the soil loss model, Revised Universal Soil Loss Equation （RUSLE） integrated with GIS has been used to estimate soil loss in the Nethravathi Basin located in the southwestern part of India. The Nethravathi Basin is a tropical coastal humid area having a drainage area of 3128 km2 up to the gauging station. The parameters of RUSLE model were estimated using remote sensing data and the erosion probability zones were determined using GIS. The estimated rainfall erosivity, soil erodibility, topographic and crop management factors range from 2948.16 to 4711.4 MJ/mm.ha-1hr-1/year, 0.10 to 0.44 t ha-1 -MJ-1.mm 1, 0 to 92,774 and 0 to 0.63 respectively. The results indicate that the estimated total annual potential soil loss of about 473,339 t/yr is comparable with the measured sediment of 441,870 t/yr during the water year 2002 2003. The predicted soil erosion rate due to increase in agricultural area is about 14,673.5 t/yr. The probability zone map has been derived by the weighted overlay index method indicate that the major portion of the study area comes under low probability zone and only a small portion comes under high and very high probability zone. The results can certainly aid in implementation of soil management and conservation practices to reduce the soil erosion in the Nethravathi Basin.

Application of Remote Sensing in Study of Slope Land Use and Soil Erosion in Subtropic Region of China

This paper introduces briefly two remote sensing case studies on land use in the subtropic region of China. One is on slope land use in the Yangtze River Three Gorges area. This is a large area of 60497 km2.First of all, geometric correction and supervised classification were conducted for ten scenes of Landsat-5 TM or MSS images. The resolution of the processed images is 50 m ×50 m on ground. By the classification the land use/cover categories in this area were discriminated. Then the croplands including rice fields and upland fields were extracted from the land use/cover maps. Simultaneously the slope grade maps were prepared based on the topographic maps. Overlaying the slope grade maps and the cropland maps, the area and percentage of the croplands in different slope grades were determined. This case study indicated that 71.5% of the uplands was situated on the slope above 15° and 25% on the slope above 25° in this area. It is dangerous, and urgent cultivation or engineering measures should be taken. Another case study is on soil erosion in Linshan County of Guangxi Province. Airphoto interpretation and supervised classification of a Landsat TM image were carried out for discriminating land cover/use categories in an area of 3557.8 km2.And the soil erosion intensity grades were determined according to the land cover/use maps and slope maps.It wed discovered that the land suffering soil erosion accounted for 2404.0 km2, 67.6% of the total area of the county. Necessary measures to control soil erosion should be taken also.

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.

Remote-sensing data reveals the response of soil erosion intensity to land use change in Loess Plateau, China

Developing an effective approach to rapidly assess the effects of restoration projects on soil erosion intensity and theirextensive spatial and temporal dynamics is important for regional ecosystem management and the development of soilconservation strategies in the future. This study applied a model that was developed at the pixel scale using water soilerosion indicators （land use, vegetation coverage and slope） to assess the soil erosion intensity in the Loess Plateau,China. Landsat TM/ETM＋ images in 2000, 2005 and 2010 were used to produce land use maps based on the object-oriented classification method. The MODIS product MOD13Q1 was adopted to derive the vegetation coveragemaps. The slope gradient maps were calculated based on data from the digital elevation model. The area of watersoil-eroded land was classified into six grades by integrating slope gradients, land use and vegetation coverage. Resultsshow that the Grain-To-Green Project in the Loess Plateau worked based on the land use changes from 2000 to 2010and enhanced vegetation restoration and ecological conservation. These projects effectively prevented soil erosion.During this period, lands with moderate, severe, more severe and extremely severe soil erosion intensities significantlydecreased and changed into less severe levels, respectively. Lands with slight and light soil erosion intensities increased.However, the total soil-eroded area in the Loess Plateau was reduced. The contributions of the seven provincesto the total soil-eroded area in the Loess Plateau and the composition of the soil erosion intensity level in eachprovince are different. Lands with severe, more severe and extremely severe soil erosion intensities are mainly distributedin Qinghai, Ningxia, Gansu and Inner Mongolia. These areas, although relatively small, must be prioritised andpreferentially treated.

Study on soil erosion dynamics in typical regionof southern China based on remote sensing, GISand gray forecast model

This paper StUdies soil erosion dynamics in the typical region of southem China based onremote sensing, GIS tecndques and gray forecast model. The resultS of survey on Xingguo countyshown the soil eroded area and annual soil erosion amount decreased by 19.09% and 43.05%reSPectively from 1958 to 1988. The results of gray forecast model presented that soil eroded areaincreased from 818.04 km2 in 1988 to 1276.69 km2 in 1995. in the meanthne the total soil erosiollamount decreased from 607.21×104 ba in 1988 to 472. 12 ×104 t/a in 1995. By comparing differentlanduse types, the soil loss modulus of the forest was the lowest with 177. 16~187.75t/km2. a, on thecontraly the bare land was the highest with 10626.76~11265.48 t/km2. a. so the high vegetationcoverage can decrease soil and water loss effectively.

Using remote-sensing technologies in combination with Cesium-137 measurements to estimate soil-erosion quantity in semi-arid steppe areas

Soil erosion by wind is one of the most important processes in the changing the earth's surface in semi-arid areas,Thus it is of great importance to study soil-erosion action.Using integrated technologies of remote sensing and geochemistry radioactivity iso-tope to extract regional soil-erosion information and to calculate quantity of soil erosion is accomplished successfully in this paper by means of beneficial experiments in the Talatan region of the Gonghe Basin,which is located in northeastern Qinghai-Tibet Pla-teau in China.The results show that the soil erosion by wind is not intensive in this region;the erosion types belong to the classes of very-soft erosion and soft-erosion type,which account for 47.12 percent and 35.58 percent,respectively,of the total study area.In total,two kinds of soil erosion account for 82.70 percent of the study area;only a small area belongs to the classes of severe erosion and very-severe erosion;this area is about 22.14 km2.Severe deposition activity has taken place in this region,and has appeared in a large area(322.67 km2),which accounts for 11.78 percent of the total study area.The results of this study show that soil erosion and deposition inventories are 870,000-1,150,000 tons and 550,000-780,000 tons,respectively,per year.The soil in-ventory shows about 320,000-370,000 tons from Talatan to Longyangxia reservoir per year.Using remote-sensing technology and 137Cs techniques is a valid means to analyze and to evaluate the quantity of soil erosion by wind in semi-arid environments.

Research on the Optimal Vegetation Cover for Remote Sensing Assessment of Soil Erosion Risk Using the Temporal Matching Relationship between Rainfall and Vegetation

Vegetation cover derived from remote sensing image is widely used for soil erosion risk assessment, but there is no clear guideline to select the most appropriate temporal satellite data. It is common practice that satellite data during growing season are randomly selected and used in soil erosion risk assessment. However, the effectiveness of vegetation in protecting the soil is quite different even if it is the same growing season since vegetation covers change as they grow. This article aims to provide a method of choosing optimal vegetation cover for studying soil erosion risk using remote sensing, that is, the vegetation cover in the most appropriate temporal period. Based on the temporal relationship of the two most active impact factors, rainfall and vegetation, an index of RV is developed and used to indicate the relative erosion risk during the year. The results show that annual variation of rainfall is significant, and vegetation is relatively stable, resulting in their matching relationship is different in each year. The correlation coefficient reaches 0.89 between RV and real sediment transport during the period when rainfall can cause soil erosion. In other words, RV is a good indicator of soil erosion. Therefore, there is a good correlation between RV maximum and the optimal vegetation cover, which can help facilitate erosion research in the future, showing good potential for successful application in other places.

Environmental Factors Affecting Temporal and Spatial Dynamics of Soil Erosion in Xingguo County, South China

By using soil erosion maps of four different time periods and a digital elevation model (DEM), in combination withthe remote sensing and GIS technologies, soil erosion dynamics in Xingguo County of Jiangxi Province in South Chinawere analyzed on both temporal and spatial scales in soils of different parent materials, altitudes and slopes. The resultsshowed that from 1958 to 2000 severe soil erosion was coming under control with a decreasing percentage of the land undersevere erosion. It was also found that the soils developed from Quaternary red clay, granite and purple shale were moresusceptible to soil erosion and that areas sitting between 200 to 500 m in altitude with a slope less than 3° or between7° to 20° where human activities were frequent remained to be zones where soil erosion was most likely to occur. Theseareas deserve special attention in monitoring and controlling.

An Integrated GIS/RS Approach for Soil Erosion Assessment and Modeling in Syrian Coastal Soils

An integrated remote sensing (RS) and geographic information system (GIS) technique was employed to characterize the spatial distribution of the risk of soil erosion by water on Latakia district, Syria. The universal soil loss equation (USLE) was used to calculate the annual soil loss rates for Latakia soils. Mainly, remote sensing data, soil survey, land use inventory, elevation data and climatic atlases are used as resource data sets to generate USLE factor values. The results revealed that integration of GIS/RS with USLE was a practical and effective approach for monitoring soil erosion over large areas.

Temporal and Spatial Conversion Analysis of Soil Erosion in the Three Gorges Region Based on RS and GIS Technique——A Case Study in Kaixian County

In this paper, Kaixian County, situated in the hinterland of the Three Gorges Reservoir Region, was selected for the case study. Factors of soil erosion were obtained based on the technique of remote sensing （RS） and geographic information system （GIS）. Combining with field survey, soil erosion data in the years of 1988, 2000 and 2004 which covered the period from the beginning of the Three Gorges Reservoir Project to nowadays were investigated through the judgment model established on soil erosion intensity. With the function of spatial analysis in the geographic information system, the analysis and appraisal of dynamic soil erosion changes were carried out, and the spatial characteristics of the vicious change were highlighted, and the main causes of the vicious change of soil erosion were explored.

Mapping of Soil Erosion Zones of Meghadrigedda Catchment, Visakhapatnam, India for Conservation <br/>—A Geospatial Approach

Meghadrigedda, a non-perennial drainage system is one of the major water resources of Vishakhapatnam city located in the northern coastal region of Andhra Pradesh, India. It traverses through the hilly terrain of Eastern GhatMobile Belt (EGMB) characterized by khondalitic rock formations. Excessive siltation scenario aggravated due to soil erosion in its catchment is threatening the very existence of Meghadrigedda reservoir. In order to assess the intensity of soil erosion as well as silt deposition in the reservoir, an integrated study has been undertaken which takes into consideration various topographic, morphological, soil, and land use/land cover characteristics of the basin. The study aims at identification and mapping of erosion prone zones with respect to silt deposition using remote sensing and GIS techniques.Alteration in human induced land use practices in its catchment due to rapid growth in population, urbanization and industrialization are found to be of prime reasons for various forms of erosion. The study has noticed that various forms of erosion like sheet, gully and stream erosion are responsible for the siltation at large scale which is causing reduction of its designed storage capacity by 40%. Various sub-watersheds of the basin have been prioritized on the basis of erosion intensity for suggesting various mitigation measures like check-dam construction, afforestation etc. to protect the reservoir from the silting problem.

基于RUSLE模型的京津冀地区土壤侵蚀时空变化分析

【目的】土壤侵蚀是一种日益严重的生态问题,已经成为全球性的环境挑战,对人类的生存和可持续发展产生了极大的威胁。因此基于多源遥感数据,【方法】通过RUSLE模型和地理探测器模型研究了1990—2020年京津冀地区土壤侵蚀在时空尺度上的动态变化,并对其驱动因素进行了分析。【结果】结果显示:(1) 1990—2020年京津冀地区的土壤侵蚀总体呈现东南低西北高的分布特征,且以微度和轻度侵蚀为主,其百分比达到73.79%。(2)京津冀大部分地区土壤侵蚀等级主要由高向微强度侵蚀转移,且转移比例都在50%以上,整体有所好转,但存在局部加剧。(3)各个影响因子对土壤侵蚀的解释力依次为:坡度>高程>土地覆盖类型>植被覆盖度>降雨量>人口密度>GDP。【结论】相关结论可为水土流失治理以及防治提供一定的科学参考,同时也可为其他地区的土壤侵蚀治理提供参考。

东北典型黑土区耕地侵蚀沟形态系统分类方法构建

侵蚀沟形态分类是认识其发展现状和潜在危害的重要方法,探究耕地侵蚀沟形态分类特征和分布特征对把握耕地侵蚀沟防治重点,预防坡耕地水土流失具有重要意义。针对现有侵蚀沟形态分类体系指标获取难、分类结果不完整等问题,利用遥感解译数据,根据系统分类和信息科学理论,结合东北黑土区现实需求,构建了耕地侵蚀沟系统分类方法,并在典型黑土耕作区海伦市进行了验证。结果表明:1)海伦市耕地侵蚀沟具有小面积、大宽度、短长度的特点,Ⅰ类和Ⅱ类为数量最多的一级分类;Ⅱ类四等微型沟(Ⅱ4T)和Ⅱ类四等小型沟(Ⅱ4S)在二级和三级分类中数量居多,易通过高标准农田建设进行治理。2)地形要素下耕地侵蚀沟形态分布差异明显,需要特别关注在高程180~<240 m,坡长35~<55 m,坡度2°~6°,西南坡区域内的Ⅰ4T、Ⅱ4S、Ⅱ4T等发育程度较低的侵蚀沟向更高发育程度的Ⅳ4M、Ⅴ4M等类型转变,建议结合农田建设及时采取综合防治措施,以防止耕地侵蚀沟的潜在破坏。3)构建的“类+等+型”耕地侵蚀沟分类定级方法,兼顾指标的易获取性和方法的易操作性,能够精准、直观地揭示耕地侵蚀沟的形态特征及其危害情况,可为侵蚀沟和黑土耕地的协同综合治理提供方法借鉴。

农田土壤理化参数快速获取技术研究进展与展望

[目的/意义]土壤是农业基本的生产资料,其质量与农业高效生产和可持续发展密切相关。由于以往对农田的高强度利用以及土壤侵蚀等原因,导致部分农田出现土壤有机质明显下降、地力减弱和生态功能退化等现象。土壤理化参数作为揭示土壤空间特征、评估土壤肥力的关键指标,对农田可持续利用起着至关重要的作用。因此,土壤理化参数信息的快速获取极为必要。[进展]探讨了农田土壤理化参数获取技术的研究意义,总结了当前用于农田土壤理化参数信息获取的主要技术,包括以电化学分析和光谱分析为主的实验室快速检验技术,以电磁感应、探地雷达、多光谱、高光谱和热红外为主的近地快速感知技术,以直接反演法、间接反演法和结合分析法为主的卫星遥感技术,以及近年的新型快速获取技术,如生物传感、环境磁学、太赫兹光谱和伽马能谱等,梳理了各方法的优缺点及适用情况。[结论/展望]结合农田环境的作业需求,依据未来研究的侧重方向提出发展建议,包括开发便携化、智能化和经济型的近地土壤信息获取系统及设备,实现土壤信息的原位快速检测。优化低空土壤信息获取平台的性能,完善数据的解译方法;联合多因素构建卫星遥感反演模型,利用多种共享开放的云计算平台实现数据的深度挖掘。深入探索多源数据融合在土壤理化参数信息获取中的研究与应用,构建泛化能力强、可靠性高的土壤信息感知算法和模型等,从而实现土壤理化参数信息快速、精准和智能化获取。

基于数字孪生的水土流失防治责任范围变化预测模型

为建立实用、高效的水土流失防治责任范围变化预测模型,提高合规性判断的准确性,在总结水土流失防治责任范围可撤销性、时空交错性、临时性和条件适用性等4个主要动态特性的基础上,提出一种基于数字孪生的水土流失防治责任范围变化预测模型。数学模型为描述防治责任范围状态的虚拟模型,防治责任范围为物理实体,模型基于防治责任范围变化主要因素的孪生数据,对防治责任范围有效性状态进行评估和预测。结果表明:模型对防治责任范围变化进行预测的正确率提升约38%,具有良好的预测防治责任范围变化的性能,有助于进一步提升提高遥感监管成果的质量,在生产建设项目遥感监管应用领域有一定的借鉴意义。

基于高分遥感调查东北黑土区10年尺度切沟治理效果

[目的]分析黑土区切沟治理措施的存量、区域差异及治理后切沟演化特征,评估10年尺度切沟治理效果。[方法]以松嫩典型黑土区为研究区,采用系统抽样方法与3期高分遥感影像解译相结合,分析了耕地切沟治理效果和复发情况。[结果]在松嫩典型黑土区的998个抽样单元中,有切沟治理措施调查单元73个,占耕地抽样单元的10.11%,93.2%分布于黑土带。2010—2018年,有治理措施的情况下,仍约30%的抽样单元切沟密度增加,尤其是强度侵蚀以上抽样单元数量增加。切沟治理措施能够有效阻控切沟的发育,约80%的切沟保持稳定或缩短,但仍有8%的切沟持续增长,另有12%的新生切沟。[结论]东北黑土区耕地切沟治理措施在2010年之后广泛分布且能够有效阻控切沟的发育,但还需要进一步改进切沟治理策略,提高切沟治理的长效性,保障黑土资源的可持续利用。

基于无人机遥感的植被覆盖与管理因子计算

[目的]研究传统遥感的混合像元分解法在无人机遥感中的应用,提出小区域尺度的植被覆盖与管理因子(C因子)快速估算方法。[方法]借助无人机航拍获取南京江宁谷里地区土地利用情况的遥感影像,采用面向对象分类法提取各类型用地的地物盖度,基于混合像元分解的C因子模型计算了研究区C值,通过与已有研究成果的分析比较,评价该方法的准确性。[结果]对象分类结果(植被、裸地和非光合地物)总正确率都在95%以上,基于混合像元分解的C因子模型估算南京江宁谷里地区的林地、耕地和草地的C值分别为0.057,0.176,0.043,结果与已有研究成果接近。[结论]利用无人机遥感进行C因子估算是可行的,且相较于传统的径流小区实测法,更为高效便捷。

基于遥感技术的东北黑土区水土流失动态监测研究

东北黑土区是我国重要的商品粮基地,近年来面临水土流失严重、面积减小、土壤质量下降等问题,已成为目前土壤保护工作中亟待解决的重要问题。以东北黑土区2018年和2022年两期遥感影像与水土保持措施的实地调查数据作为数据源,利用目视识别法开展影像解译,并通过中国土壤流失方程CSLE进行土壤侵蚀模数的计算,对东北黑土区的水土流失变化情况及原因进行分析,结果表明:耕地、草地、建设用地、其他土地面积减少,园地、林地、交通运输用地、水域及水利设施用地面积增加,造林、种草、封育、地埂、水平阶/反坡梯田等面积共增加0.84万km^(2);对比2018—2022年东北黑土区的水土流失情况,整体呈向好趋势,土壤侵蚀面积共减少约1.01万km^(2);从侵蚀强度来看,除轻度侵蚀面积增加约0.45万km^(2)外,中度、强烈、极强烈、剧烈侵蚀面积分别减少约0.43万、0.24万、0.28万、0.51万km^(2);从不同省份侵蚀面积变化情况分析,内蒙古自治区东四盟的侵蚀面积减少最多,共减少约0.37万km^(2),辽宁省侵蚀面积变化最小,共减少约0.06万km^(2);耕地、建设用地等土地利用类型面积的减少,以及林地、交通运输用地等土地利用类型面积的增加,均可大幅减少土壤侵蚀面积,同时水土保持措施面积的增加也可有效阻止土壤侵蚀的发生。总体来看,东北黑土区水土流失治理效果显著,生态环境得到改善,持续进行东北黑土区水土流失治理对环境保护具有重要意义。