Influence of landuse on soil erosion risk in the Cuyaguateje watershed (Cuba)

Landuse changes may dramatically enhance erosion risk. Besides deforestation, also arable landuse may have an important influence on soil loss. We investigated the erosion risk in a 151 km² subwatershed of the Cuyaguateje watershed (Cuba) using the RUSLE model. It was found that the valleys used for agriculture have the highest erosion risk, with actual erosion surpassing soil loss tolerance. Over the period 1985–2000, about 14 km² of forest has been converted into arable land. As a result, the area with a very high erosion risk increased with 12%. On arable land it was found that the crop management factor C of a “tobacco/maize” rotation was 0.478, compared to 0.245 for a rotation of various crops (sweet potato, beans, maize, cassava and fallow). When maize in the “tobacco/maize” rotation was intercropped with a leguminous crop (hyacinth bean) the C factor decreased to a value of 0.369. Also contouring may halve soil loss on moderate slopes (< 10%) when high ridges are applied, which is in Cuba generally the case for maize, cassava and sweet potato.     

A detailed reconstruction of changes in the factors and parameters of soil erosion over the past 250 years in the forest zone of European Russia (Moscow region)

Accelerated soil erosion is a major threat to soil, and there are great variations in the rate of soil erosion over time due to natural and human-induced factors. The temperate forest zone of Russia is characterized by complex stages of land-use history (i.e. active urbanization, agricultural development, land abandonment, etc.). We have for the first time estimated the rates of soil erosion by the WaTEM/SEDEM model (rainfall erosion) and by a regional model (snowmelt erosion) over the past 250 years (from 1780 to 2019) for a 100-km² study site in the Moscow region of Russia. The calculations were made on the basis of a detailed historical reconstruction of the following factors: the location of the arable land, crop rotation, the rain erosivity factor, and the maximum snow water equivalent. The area of arable land has decreased more than 3.5-fold over the past 250 years. At the end of the 20th century, the rates of gross erosion had declined more than 5.5-fold (from 28 × 10³ to 5 × 10³ t?ha^?1?yr^?1) in comparison with the end of the 18th century. Changes in the boundaries of arable land and also the relief features had led to a significant intra-slope accumulation of sediments. As a result of sediment redeposition within the arable land, the variation in net soil erosion was significantly lower than the variation in gross soil erosion. The changes in arable land area and in crop composition are the factors that have to the greatest extent determined the changes in soil erosion in this territory.     

Assessment of soil erosion risk in England and Wales

Abstract. Information on rainfall erosivity, soil erodibility and land capability is combined to produce a map of England and Wales showing areas with a risk of soil erosion at rates above the soil loss tolerance level. About 20 500 km² or 37% of the arable area is at risk. Given the shallow soils and current rates of erosion, sustained use of this area for cereal, sugar beet and vegetable production beyond the first quarter of the next century is threatened. A further 4000 km² is at risk in non-arable areas, mainly associated with blanket peat in the uplands and with coastal sand dunes.     

Soils at risk of accelerated erosion in England and Wales

Abstract. The 296 soil associations of the National Soil Map of England and Wales are placed into five categories of erosion risk. These are based on land use, landform and soil properties and take into account the extent of erosion in the uplands, and its frequency, extent and rates in the lowlands. Erosion of arable land is by water or wind, but in the uplands frost action and disturbance by sheep are also important. A large proportion of arable England (36%) is at moderate to very high risk of erosion, including much of the better drained and more easily worked land, especially sandy soils. In the uplands thin soils or deep peats are most at risk. If land use changes, because of increasing intensification of agriculture or in response to climatic changes, many soil associations will become more at risk of erosion.     

基于黄土沉积速率的土壤侵蚀危险度评价

土壤侵蚀危险度是评估和预测侵蚀作用破坏土地资源和生态环境危险性的重要指标,也是科学防治水土流失的基础。利用14 C测年技术对陕北黄土高原黄土沉积速率进行研究,并通过计算土壤侵蚀模数与黄土沉积速率的比值,对该研究区的土壤侵蚀危险度进行评价。结果表明:洛川县、延长县和横山县采样点的黄土沉积速率分别为0.017 9cm/a,0.015 3cm/a和0.021 3cm/a,土壤侵蚀危险度分别为14.1,43.3和24.8,均远远大于临界危险度值1,因此该地区为水土流失重点防治区域。通过该项研究可以为水土保持治理及规划提供科学参考,并为环境治理决策部门提供理论依据。     

山东低山丘陵土地整治区耕地生态价值评价

耕地具有重要的生态价值,但难以定量评价。低山丘陵是中国土地整治的重要区域,整治前后耕地生态价值发生变化。该文以山东省莱芜市里辛土地整治项目为例,基于生态服务价值评价理论,采用替代法、市场定价法等方法,探讨了低山丘陵土地整治区耕地生态价值评价方法及整理前后耕地生态价值变化。结果表明,研究区耕地气体调节、营养循环、水源涵养和土壤保持4种生态服务功能的整理前后总价值分别为428.61和774.90万元,耕地具有较高的生态价值,其中气体调节价值最大。整理后耕地生态价值比整理前增加346.29万元,增值率80.79%,土地整理生态效益显著,其中气体调节价值增加最多。该研究方法对耕地生态价值定量评价有借鉴意义,评价结果可为莱芜市里辛土地整理绩效评价提供科学依据。     

基于GF-6 WFV影像和CSLE模型的山区耕地侵蚀定量评价及特征分析

坡耕地是高原山区水土流失最主要的策源地,其严重的土壤侵蚀已经威胁到山区粮食安全和农业可持续发展。该研究以云南省土壤侵蚀较为严重的文山州为例,在第三次全国国土调查数据、水利普查抽样单元和GF-6 WFV等多源遥感数据基础上,结合随机森林算法快速自动提取梯田,利用CSLE模型对山区耕地土壤侵蚀进行精细定量评估,并以空间自相关分析揭示土壤侵蚀空间分布特征。结果表明：1）文山州耕地空间异质性显著,以广南、西畴、马关一线为界,呈自西向东递减格局;坡耕地占耕地总面积的79.27%,3 929.57 km2耕地采取水土保持工程措施,占49.79%。2）全区耕地平均侵蚀模数为5 180.72 t/(km²•a),其中69.99%的耕地遭受轻度及以上侵蚀;耕地总侵蚀量达4 081.50万t,其中未采取保护措施耕地的侵蚀贡献率为79.40%,土壤侵蚀对坡度和高程的响应存在差异,具有明显垂直地带性特征,1 000～1 800 m高程带侵蚀情况严峻,3 073.65万t侵蚀量源于20°以上陡坡,占侵蚀总量的75.30%。3）侵蚀空间聚集特征鲜明,文山州南部和东部为侵蚀高值中心,低值中心见于中西部和北部。利用区域侵蚀因子自动提取产品和空间自相关分析能够快速完成侵蚀精细定量评估,可为区域水土保持资源精准分配和生态环境建设提供参考。     

基于综合判别法的广东省水土流失状况遥感分析

以2009和2010年10 m分辨率的ALOS多光谱遥感影像为数据源,采用计算机自动分析与人机交互判别相结合的方法,对广东省水土流失状况进行了遥感分析。结果表明:广东省土地利用以林草地、水田、建筑用地、水域和旱地为主,植被覆盖状况良好,珠三角和粤西地区地形平缓,粤北山区地形起伏较大;全省水土流失总面积20945.87 km 2,其中自然侵蚀面积14781.06 km 2,人为侵蚀面积6164.81 km 2;全省水土流失以轻度和中度侵蚀为主,主要分布在河源、梅州和云浮等地,其中生产建设活动导致的人为侵蚀集中分布在惠州、清远和广州等地。     

基于GIS的太原市土壤侵蚀定量研究

基于GIS和RS技术,采用修正版的通用土壤流失方程(RUSLE),在对区域土壤侵蚀影响因子进行分析的基础上,对太原市土壤侵蚀进行定量研究,并根据土壤侵蚀强度进行了分级。结果表明,太原市土壤侵蚀以微度和轻度所占比例最大,主要分布在中南部的林地,以及东部和南部的以梯田为代表的耕地地带(坡耕地除外),约占市区总面积的1/2以上。土壤侵蚀较严重的地带主要分布在北部以及边缘地带。其中,荒草地、裸岩石砾地等未利用地的侵蚀强度最大,其次是建设用地、水体和耕地,林地的侵蚀强度最小。总体上看,太原市大部分地区的土壤侵蚀程度相对较低,土地利用状况相对较为合理,但亦有一部分地区的土壤侵蚀较为严重,尽管所占面积较小,但不可忽视。     

Erosion rates on bare loamy sand soils in east Shropshire, UK

Abstract. Results from over seven years of monitoring of erosion rates on bare arable loamy sand soils at the Hilton experimental site, Shropshire, UK, are reported. On bare plots, rates are very variable; erosion during one summer convectional storm exceeded that recorded during six individual years of plot measurement. Exposure of erodible arable soils to convectional storms puts them at risk of excessive erosion. Plot erosion rates were frequently high, with rates up to 67.4 t/ha occurring during an individual storm. Rates were influenced by rainfall erosivity, slope steepness and soil organic content. Mean soil organic content on the bare plots decreased over five years by 0.08%/yr.     

我国水土流失状况与发展趋势研究

利用第3次水土流失普查数据,分析我国目前水土流失总体状况,水蚀、风蚀和冻融侵蚀等不同类型水土流失状况以及东部、东北、中部和西部地区4大经济区域水土流失状况,并对水蚀区侵蚀危险度现状进行了评价。结合水利部开展的第1、2次全国水土流失普查数据,分析15年来水土流失的动态变化情况,以及我国主要江河流域多年来土壤流失量变化的状况。     

澜沧江中下游流域土壤侵蚀时空演变特征

为了探究土壤侵蚀演变机制,以澜沧江中下游流域为研究区域,利用改进的土壤流失方程(RUSLE)模型,开展流域内土壤侵蚀时空演变特征研究,引入随机森林算法探讨了流域内土壤侵蚀因子的相对重要程度。结果表明:澜沧江中下游流域2005—2015年土壤侵蚀量为0～1.89万t/(km²·a),平均土壤侵蚀模数为0.252万t/(km²·a),中下游子流域平均土壤侵蚀模数处于较低风险以上和中风险侵蚀以下级别。自2005年以后,澜沧江中下游流域土壤侵蚀空间分布特征呈现中度侵蚀风险区域扩张,高度和低度侵蚀风险收缩的趋势。随机森林算法结果发现植被覆盖管理因子和地形因子是影响澜沧江中下游流域土壤侵蚀的主要因素,土壤可蚀性因子、降雨侵蚀因子和水土保持措施因子的相对重要程度偏低,均未超过20%。可见,土壤侵蚀的时空异质性主要是由于植被覆盖和地形影响改变了局部气候而导致的。     

十大孔兑流域水土流失分布特征及防治对策

[目的] 通过分析十大孔兑水土流失面积、强度及水土流失动态变化,为流域综合治理提供参考依据。[方法] 基于全国土壤侵蚀遥感调查结果和全国水土流失动态监测成果,对比分析流域水土流失及其分布、动态变化。[结果] 十大孔兑流域植被面积占流域面积的63.97%,以中低覆盖和低覆盖为主,分别占植被覆盖面积的48.85%和36.54%。2021年水土流失面积为4374.98 km²,占流域面积的40.63%;与2020年、1999年和1985年相比,2021年水土流失分别减少46.32,3 664.50,4 958.03 km²,水土流失主要分布在草地、林地、耕地和其他土地4个地类上,占水土流失总面积的96.69%。[结论] 十大孔兑依然是黄河流域水土流失治理的难点地区,高强度侵蚀减少与年度监测成果未考虑沟道侵蚀有关;该区应坚持以“以沙棘种植为主的植被建设,以淤地坝建设为重点的工程布局,以锁边固沙为前提的治沙方针,大力推进拦沙换水试点工程”的流域综合治理策略。     

东露天煤矿区采矿对土地利用和土壤侵蚀的影响预测

黄土区大型露天矿区是一种剧烈的人工扰动区域,采矿活动对土地资源和生态与环境破坏非常严重,正确预测人工开采引发的人为加速土壤侵蚀与土地利用变化,可为生态脆弱煤矿区的生态恢复和重建提供依据。该文采用RS、GIS技术、统计分析、类比和趋势外推相结合的方法,对东露天矿区2005～2080年的土地利用变化和水土流失进行了预测性研究。结果表明：75年间,在没有采取生态重建的措施下,农用地减少3666.07 hm²,未利用地减少1402.13 hm²,居民点用地减少121.80 hm²,全部变为独立工矿用地。土地利用结构和类型由多样性向单一类型的裸露的独立工矿用地发展,水土流失量由54.50万t/a变为77.85万t/a。     

Soil erosion: An important indicator for the assessment of land degradation neutrality in Russia

This review of soil erosion (SE) studies in Russia focuses on two main tasks: (i) ensuring the completeness and reliability of SE data in Russia, a large country (17.1 million km²) with a variety of natural and socio-economic causes of land degradation, (ii) assessing the possibility of including a SE indicator among the indicators of land degradation neutrality (LDN). A wide range of statistical, remote sensing, mathematical modeling data, the results of scientific and field studies obtained at different levels were analyzed. It is asserted that in Russia the total area of eroded lands and those under erosion risk occupy more than 50% of all agricultural lands, whereas soil fertility of croplands decreased in Soviet time (from 1950s to 1980s) by 30–60% only due to water erosion. However, recent scientific studies indicate a decrease in erosion rate and in the area of eroded land during the last 30–40 years as a result of abandonment of arable land and subsequent overgrown with natural vegetation. The climate change resulting in decrease of the depth of soil freezing, flow of spring runoff also adds to the decrease of soil erosion. The SE indicator was suggested as an important complement to three global LDN indicators. At national and subnational level, it can be interpreted through such indices as “Rate of soil loss” (ton ha-1 yr-1) and “Total soil loss” (1000 tons, in certain area during selected time period). At local level the set of indices can be wider and site-specific, including those obtained through remote sensing data by using the classifier of thematic applications of remote sensing technologies; the example was tested at the local site.     

Soil erosion potential of organic versus conventional farming evaluated by USLE modelling of cropping statistics for agricultural districts in Bavaria

Abstract. Organic agriculture (OA) aims to identify a production regime that causes less environmental problems than conventional agriculture (CA). We examined whether the two systems differ in their susceptibility to soil erosion by water. To account for the large heterogeneity within the rotations practised on different farms, we chose a statistical evaluation which modelled erosion using the USLE method from the cropping statistics for 2056 districts in Bavaria (70 547 km²; 29.8% arable). Physical conditions of erosion were determined in a rectangular grid yielding 13 125 grid-cells of c. 5 km² each. For validation, erosion was measured in 10 sub-watersheds on two neighbouring OA and CA farms over 8 years (287 erosive events). On average, about 15% less erosion on arable land was predicted for OA than for CA due to the larger area of leys, although OA occupies areas that are susceptible to erosion more often than CA. The same conclusions could be drawn from the validation data. These data also demonstrated that erosion could be reduced considerably below 1 t ha⁻¹ yr⁻¹ with best management practices under both farming systems. In contrast, at the countrywide scale, cropping did not change adequately with site conditions favouring erosion. The need for erosion control seems not to influence crop rotation decisions on erosion-prone sites.     

基于土壤侵蚀时空演变的县域生态承载力评价

[目的]探究土地类型变化背景下土壤侵蚀和生态承载力的时空演变及相关关系,对提高生态承载力水平、优化土地利用结构和水土保持措施配置具有重要意义。[方法]以江西省宁都县为研究区域,基于自然资源和社会经济数据,运用InVEST模型与空间主成分方法,分析了土壤侵蚀变化对生态承载力的影响。[结果](1)宁都县主要土地利用类型为林地、耕地和草地,9年来土壤侵蚀程度2010年>2015年>2018年,分别为597.42,591.29,583.51 t/(km²·a),侵蚀类型以微度为主,在中部、西北部和东南部等地区,建设用地和耕地土壤侵蚀程度严重。(2)宁都县生态承载力西南低、东北高,9年来生态承载力整体上略有好转;三期土壤侵蚀程度严重的区域,生态承载力水平低。(3) 2010—2018年,宁都县开展规模化整地,使林地、荒地(未利用地)转为园地、耕地,增加了土地覆被度,加之降雨量减小,径流冲刷减弱,侵蚀模数大幅降低,分别减少了178.19,876.32,2 205.07 t/(km²·a),其他土地利用类型侵蚀模数变化较小,总体来看土壤侵蚀模数...     

A comparison of runoff and erosion rates on bare and grassed loamy sand soils

Abstract. Runoff and erosion rates on loamy sand soils were measured at the Hilton experimental site, Shropshire. Little runoff and no erosion occurred on a steep runoff plot inserted into permanent grassland. Most precipitation infiltrated into the soil and was transmitted down slope as interflow within the Ah horizon. In contrast, considerable amounts of runoff and erosion occurred on the bare arable plots. These results suggest that incorporation of strips of permanent grassland into arable systems could assist soil and water conservation. Considering the high erosion rates on bare steep plots, conversion of slopes > 12° to permanent grassland seems appropriate.     

基于GIS的广东省水土流失潜在危险度评价

以GIS为支撑,选取整个广东省为研究区域,基于对自然界潜在水土流失强度的客观认识,综合考虑区域内坡度、坡长、土壤、降雨及地质等因子,通过空间叠加分析,对区域水土流失潜在危险度进行了度量和评价,生成了广东省水土流失潜在危险度分布图。分析结果表明,广东省水土流失潜在危险分布区以无险、轻险型区为主,其面积占全省面积的80%以上,主要分布在平原区;重险型区域面积占该省面积的18.3%,主要分布在东部、南部、北部地势较高,降雨量较大的山丘区,区内植被一旦遭到破坏,极易发生流失,是水土保持工作中的重点预防保护区域。     

利用CSLE模型的东北漫川漫岗区土壤侵蚀评价

东北黑土区是中国重要的商品粮基地,土壤侵蚀正日益破坏着宝贵的黑土资源,严重威胁到中国粮食生产安全。土壤侵蚀评价是土壤侵蚀防治的依据和水土保持效益评估的重要途径。土壤侵蚀的多尺度特征及其影响因素的复杂性对土壤侵蚀评价提出更高的要求。为探讨土地利用和地形对土壤侵蚀的影响,以及更好地呈现土壤侵蚀评价的结果,该研究以位于东北漫川漫岗区的拜泉县为例,运用中国土壤流失方程(Chinese Soil Loss Equation,CSLE)定量评价了拜泉县的土壤侵蚀状况,分析了土地利用和地形因素对土壤侵蚀的影响,并提出了实现区域土壤侵蚀评价"落地"的方案。结果表明:拜泉县平均土壤侵蚀模数为6.77 t/(hm~2·a),土壤侵蚀面积比例为39.35%,极强烈和剧烈侵蚀的高侵蚀主要分布于拜泉县的东南部丘陵区和西北部的漫川漫岗区。坡度越大,土壤侵蚀模数越高。但随着坡长的变长,土壤侵蚀模数呈现出先增大后减小的变化趋势。对侵蚀量的贡献,来源于1～2°的坡度范围侵蚀量最大,其次为3～5°和2～3°。100～200 m的坡长对侵蚀的贡献最大,其次为200～400 m和50～100 m的坡长。坡耕地应该是土壤侵蚀防治的重点区域。在小流域的尺度上,选取土壤侵蚀面积比例进行土壤侵蚀评价,可以更好地服务于区域水土保持规划,是实现区域土壤侵蚀评价"落地"的有效途径。