Soil Erosion In Region Research Articles

Rainfall and tillage impacts on soil erosion of sloping cropland with subtropical monsoon climate — A case study in hilly purple soil area, China

Under global warming, storm events tend to intensify, particularly in monsoon-affected regions. As an important agricultural area in China, the purple soil region in the Sichuan Basin, where it has a prevailing monsoon climate, is threatened by serious soil erosion. Tillage operations alter runoff and soil erosion processes on croplands by changing the physical properties of the soil surface. To clarify the relationship between tillage and soil erosion in the purple soil region, three different tillage practices in this region were investigated at the plot scale over 4 years: bare land with minimum tillage (BL), conventional tillage (CT) and seasonal no-tillage ridges (SNTR) which was initially designed to prevent soil erosion by contoured ridges and no-tillage techniques. The results showed that although there were no significant differences in the surface runoff and soil erosion among the three practices, BL caused relatively high surface runoff and soil erosion, followed by CT and SNTR. Classification and comparison of the rainfall events based on cluster analysis (CA) verified that the surface runoff was not significantly different between most intensive event and long intensive events but was significantly different between most intensive and short and medium-duration events. Only the rainfall events with the highest rainfall intensity could trigger serious soil erosion, up to moo kg ha(-1) in the region. Further detailed investigations on the effects of tillage operations on the soil erosion in a subtropical region with a monsoon climate are needed to provide a basis for modeling catchments and designing better management practices.

Improved Hillslope Erosion Module for the Digital Yellow-River Model

AbstractSevere soil erosion in the Loess Plateau region and associated large sediment discharge downstream in China have been of great concern for years. A physically based distributed model, the Digital Yellow River model (DYRIM), was developed in 2007 for land management at the basin scale in this region. In DYRIM, an explicit sediment yield equation was derived based on simple assumptions where sediment discharge would increase nonlinearly with the slope length, leading to unrealistic results as the spatial scale increases. The main aims of this study were to reformulate the module of DYRIM in comparison with other process-based erosion models; to develop a generic framework for erosion prediction and simulation of erosion and sediment delivery processes within storm events; to validate the new hillslope erosion module for improved performance across a range of spatial scales; and to evaluate parameter consistency among different runoff events. Observed flow and sediment discharge data for 16 runoff ev...

The Transformation of Agricultural Development towards a Sustainable Future from an Evolutionary View on the Chinese Loess Plateau: A Case Study of Fuxian County

The Loess Plateau in China receives lots of attention from around the world. The expansion of bad agricultural practices for hundreds of years aggravated the soil erosion on the Loess Plateau, however, and a lot of efforts were and are being made to reduce the serious soil erosion as well as regional poverty. Agricultural development of the Loess Plateau is still confronted with intricate challenges such as food concerns, environment concerns, and regional poverty. The strategy of development towards sustainability offers a possible and important way to face the challenges. This study tried to develop a holistic “variation-selection-replication-retention” model to analyze the transformation of agricultural development from an evolutionary view which is generally integrative. It is indicated that policies should be lively and vibrant organisms full of innovations owning to ever-changing environment in the evolutionary view. Under this analytical framework, one possible path from serious soil erosion region to region with sustainable agriculture could be recognized in the case study of Fuxian County: serious soil erosion regions → regions with poor production conditions → production-optimized regions → regions with developed agriculture → regions with sustainable agriculture. Diversified integrative development is suggested due to regional differences and the possible developing order in Fuxian County. State-subsidized “Grain for Green” policy and diversified land use are necessary for the transformation of serious soil erosion regions which are usually trapped in regional poverty. To the transformation of regions with poor production conditions, a state-subsidized “production optimization” policy and diversified land use deserve to be considered, due to regional poverty in regions with poor production conditions. Agricultural scale operation is priority for the transformation of production-optimized regions towards agricultural modernization. Ecological thinking is very helpful for the transformation of regions with developed agriculture. The area of serious soil erosion regions in Fuxian County has dropped down from 1760 km2 in 1949 to 360.6 km2 in 2010. The diversified integrative routine tends to be one possible way to realize the development towards sustainability.

Geomorphological inheritance for loess landform evolution in a severe soil erosion region of Loess Plateau of China based on digital elevation models

The influence of pre-quaternary underlying terrain on the formation of loess landforms, i.e., the geomorphological inheritance issue, is a focus in studies of loess landforms. On the basis of multi-source information, we used GIS spatial analysis methods to construct a simulated digital elevation model of a pre-quaternary paleotopographic surface in a severe soil erosion area of the Loess Plateau. To reveal the spatial relationship between underlying paleotopography and modern terrain, an XY scatter diagram, hypsometric curve, gradient and concavity of terrain profiles are used in the experiments. The experiments show that the altitude, gradient and concavity results have significant linear positive correlation between both terrains, which shows a relatively strong landform inheritance relationship, particularly in the intact and complete loess deposit areas. Despite the current surface appearing somewhat changed from the original shape of the underlying terrain under different erosion forces, we reveal that the modern terrain generally smoothes the topographic relief of underlying terrain in the loess deposition process. Our results deepen understanding of the characteristics of geomorphological inheritance in the formation and evolution of loess landforms.

冻融交替后不同尺度黑土结构变化特征

PDF HTML阅读 XML下载 导出引用 引用提醒 冻融交替后不同尺度黑土结构变化特征 DOI: 10.5846/stxb201307031829 作者: 作者单位: 东北林业大学 林学院,东北林业大学 林学院,东北林业大学 林学院,东北林业大学 林学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(41271293);国家自然科学青年科学基金项目(41302222)资助 Effects of freeze-thaw cycles on black soil structure at different size scales Author: Affiliation: Northeast Forestry University,College of Forestry,Northeast Forestry University,College of Forestry,Northeast Forestry University,College of Forestry,Northeast Forestry University,College of Forestry Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:冻融交替是改变黑土结构、加剧土壤侵蚀的重要因子.以典型黑土区耕作土壤为研究对象,采用野外季节性冻融循环与室内模拟冻融循环相结合、X射线计算机断层摄影(CT)与扫描电子显微镜(SEM)相结合的方法,通过水分物理性质、团聚体破坏率、孔隙数目、孔隙面积、孔隙成圆率、孔隙Feret直径的测定与分析,研究了冻融交替后0-40 cm、40-80 cm和120-160 cm 3个土层以及田间季节性冻融环刀、室内模拟冻融CT扫描和室内模拟冻融SEM3种方式下黑土结构特征的变化规律.结果表明:冻融交替能够对不同土层和不同尺度的耕地黑土结构产生不同程度的影响.季节性冻融后,表层土壤容重升高,非毛管孔隙度和持水能力显著降低(P < 0.05),40-80 cm土层团聚体破坏率增加40.97%(P < 0.05),土壤抗蚀性有所削弱,120-160 cm土壤没有受到季节性冻融的显著影响.CT扫描尺度上,3个土层均以1-2 mm径级的孔隙数目为最多,形状也相对规则、接近圆形;冻融循环没有对表层土壤大孔隙结构产生影响,却能够显著降低40-80 cm土层范围内大孔隙面积以及Feret直径(P < 0.05).SEM扫描显示冻融后土壤表面粗糙度增加,颗粒松散、脱离,孔壁断裂,证明了冻融交替对土壤微结构的破坏作用;同时结合电子能谱的元素分析可知冻融交替能够改变土壤颗粒表面化学特征. Abstract:Alternating freezing and thawing is a critical factor associated with soil structure change and accelerates soil erosion in the black soil region of Northeast China. Based on the soils sampled from fields of the black soil region, the effects of freeze-thaw cycles on soil structure at different soil depths (0-40 cm, 40-80 cm, 120-160 cm) and size scales (field core sampling scale of seasonal freeze-thaw cycles, computerized tomography [CT] scale of artificial freeze-thaw cycles, and scanning electron microscope [SEM] scale of artificial freeze-thaw cycles) were studied. We measured and analyzed the hydro-physical properties, percentage of aggregate disruption (PAD), pore number, pore area, pore roundness, and Feret diameter of pores in the field and lab by using CT and SEM methods. Results showed that: freeze and thaw alternation affected black soil structure from different soil depths and different size scales both in seasonal field condition and artificial freeze and thaw cycles condition. At the scale of seasonal freeze-thaw cycles, bulk density of top soil (0-40 cm) increased, total porosity decreased significantly, with non capillary porosity decreasing dramatically. Water holding capacity decreased consequently(P < 0.05). Within the soil depth of 40-80 cm, bulk density and porosity did not change significantly, but PAD increased by 40.97%(P < 0.05)resulting in weak erosion resistance. Hydro-physical properties and aggregate breakdown characterization of soils in the depth range of 120-160 cm were not changed significantly by seasonal freeze and thaw cycles. At the size scale of CT, the alternation did not change the characterization of macro pores in 0-40 cm but significantly reduced the average pore area, roundness and diameter after freeze and thaw cycles. While the average area and diameter decreased significantly in the 40-80 cm depth, this might result in poor infiltration and water movement to the subsoil. Pore area of 1-2 mm and > 5 mm decreased 9.58% and 42.19% (P < 0.05), respectively. Structure of soils from 120-160 cm underwent by artificial freeze-thaw cycles showed similar results as field scale did, were not affected significantly by alternate artificial freeze and thaw cycles. The number of pores with diameter between 1 and 2 mm was predominant the pore size distribution through three soil depths. At the scale of SEM, the roughness of the soil surface and alveolate cells were significantly increased; we also observed micro-aggregate displacement and rearrangement, and disruption of the pore walls. Integrating electron spectroscopy results of 40-80 cm depths, carbon and calcium did not change after 6 freezing and thawing cycles, but oxygen group elements decreased. Magnesium, silicon, aluminum, potassium and iron elements increased to different degrees, and the total increment equaled to the decrease quantity of oxygen group element. The packing arrangement of oxygen group elements and metallic oxide are the key factors to determine the type and surface chemistry of soil clay minerals, so the amount of change in oxygen group and other elements gives indirect evidence that freeze and thaw cycles can affect soil microstructure. But to determine whether or not freeze and thaw cycles would change the crystal lattice structure of clay minerals, further research will be needed and must be approached from the view of soil chemistry and minerology. 参考文献 相似文献 引证文献

Research of coupling of eco-economic systems of soil erosion regions based on the PSR model— A case study of Zhuxi River Basin

本研究利用2000年和2009年两期社会经济和自然地理数据, 建立了朱溪河流域生态 经济系统PSR模型, 并采用熵权法为指标体系确权; 利用压力、状态、响应、综合发展水平和耦合协调度等指标, 分析了流域生态 经济系统演化态势和主要驱动因素。结果表明: (1)压力指标呈不均衡变化, 得分从80.0微降为79.0; 系统状态改善明显, 人类响应积极, 得分分别从70.9和67.5上升到94.0和87.5; 综合发展水平快速上升(得分从66.1上升为93.6)且空间差异缩小(变异系数从0.07缩小为0.05), 耦合协调程度下降(得分从92.7下降为83.8)且空间差异有所扩大(变异系数从0.09扩大为0.19), 表明流域生态 经济系统演化迅速但还没有实现系统耦合协调。(2)种植业比重、非农收入、耕地面积、人口流出、土地流转、纯收入和水土保持投入等关键因子控制着流域生态 经济系统演化; 压力、响应因子是系统耦合协调的主要影响因子, 状态因子则是系统综合发展水平的主要影响因子; 这些影响因子是人为调控关键着力点。(3)流域生态 经济系统正从高水平不稳定状态向高水平稳定状态过渡, 处于"系统重建"向"系统耦合"演进的阶段。

Comments on “Monitoring soil erosion in Cappadocia region (Selime–Aksaray–Turkey)” by Yilmaz et al. (Environ Earth Sci 2012, 66:75–81)

Yilmaz et al. (2012) presented a monitoring survey on soil erosion carried out around fairy chimneys of Cappadocia region of Turkey. They scanned the study area by geodetic robotic total station at five different times and calculated the volume differences in order to find out the total erosion during that given time interval. They finally analyzed the relationship between erosion and meteorological data and proposed that climatic conditions, especially rainfall, are an important eroding agent in the formation of this landscape. Whereas we welcome quantitative erosion surveys that are practically nonexistent in Turkey, the geological and geomorphological descriptions of the study area and scientific background contain vital mistakes that are totally unacceptable. Herein, some important ones are commented upon. Although the aim of Yilmaz et al.’s work is presented as ‘‘the study of the role of erosion of the surrounding soil in the formation of fairy chimneys’’, it is clear from their Figs. 1 and 4, where they show a photograph of the study area, that their work does not deal with any soil formation but rather is an outcrop of eroding ignimbrite. Therefore, the title of their work is misleading to say the least and do not represent their survey topic. On the other hand, even if we assume that the scanned area was covered by soil, which we insist is not the case, we are than entitled to question the use of such a method to measure the fairy chimneys erosion rates where no soil is involved during their formation. During the description of their study area the authors state, ‘‘the region was formed sixty billion years ago’’! It is common knowledge that the age of the Earth is 4.54 ± 0.05 billion years based on evidence from radiometric dating of meteorite material, which is similar to the ages of the oldest known terrestrial and lunar rocks (Dalrymple 2001). We believe that the authors and the reviewers did not see this obvious mistake. However, even if we assume that they meant ‘‘sixty million’’ instead of ‘‘sixty billion’’ they are still very far away from the calculated age of the rocks in the area. The reality is that the volcanism in Cappadocia situated in Central Anatolian Volcanic Province (CAVP), dates back to Late Miocene (around 10 My, My = Million years) to Holocene (Le Pennec et al. 2005; Aydar et al. 2012) (Fig. 1). The authors scientific inconsistencies do not end on the formation age of the study area as they claim that all rocks forming fairy chimneys were produced ‘‘by soft layers of lava and ash erupted from Erciyes, Hasan and Gullu volcanoes’’. Actually, these three stratovolcanoes are mainly Quaternary in age (around 2.5 My) (Aydar et al. 1995; Aydar and Gourgaud 1998; Kurkcuoglu et al. 1998; Şen et al. 2003) while the youngest ignimbrite layer (Kizilkaya Ignimbrite) that is known to form basin-wide mesas in the region is 5.2 My of age (Le Pennec et al. 1994; Aydar et al. 2012), hence was emplaced well before the eruption of these volcanoes. The stratigraphical framework of the region is very well established by several works where Ar–Ar and U–Pb zircon ages between 10 and 5.2 My are proposed for the formation of the ignimbrites that are susceptible to form fairy chimneys (Pasquare 1968; Innocenti et al. 1975; A. Ciner (&) Geological Engineering Department, Hacettepe University, Ankara, Turkey e-mail: aciner@hacettepe.edu.tr

Dynamic of soil exposure intensity and its effect on thermal environment change

AbstractLarge area exposure of bare soils caused by soil erosion has serious impacts on the regional ecological environment, such as the rise of land surface temperature (LST). As a typical reddish soil erosion region in southern China, the hilly area in County Changting has been called flame hilly area because of extensively exposed reddish soils and hot weather in the area. This study utilizes remote sensing technology to investigate dynamic of soil exposure intensity (SEI) and accompanied soil heat flux and LST changes during the period from 1988 to 2010 in the county. Results show that owing to the 22‐year treatment of soil erosion, the SEI in the main soil loss areas of the county has declined by 20.26%, high SEI area has reduced by 81.95%, and soil heat flux has decreased by 33.28%. All of these have contributed to the decrease in LST differences between exposed and vegetated areas by 20.8% during the study period. This indicates an improvement of the thermal environment in the flame hill area once severely exposed. Detailed quantitative relationship analysis can find that (1) SEI is positively linearly correlated with soil heat flux and LST and (2) each decrease in SEI by 0.1 unit in the future would reduce LST difference by 0.88 °C (or 1.01 °C when accompanied by an equal increment in fractional vegetation cover).

Spatial Application of WEPS for Estimating Wind Erosion in the Pacific Northwest

<abstract> <bold><sc>Abstract.</sc></bold> The Wind Erosion Prediction System (WEPS) is used to simulate soil erosion by wind on cropland and was originally designed to run simulations on a field scale. This study extended WEPS to run on multiple fields (grid cells) independently to cover a large region and conducted an initial investigation to assess how well WEPS performed in that environment by comparing simulations for two historical dust events with field observations and satellite images in the Columbia Plateau region of Washington. We modified the WEPS source code to allow it not only to run on multiple grid cells but also to save the state of the simulation so that it can be re-initiated from that state in future runs, allowing the model to be started and then stepped through time incrementally under various future climate or forecast weather scenarios. We initially ran WEPS on the entire state of Washington, with the entire Pacific Northwest region as our ultimate target area, to provide PM₁₀ and eventually PM_2.5 emissions from wind erosion events as input to the chemical transport model CMAQ, which is used by the AIRPACT regional air quality modeling system for the Pacific Northwest. Three principal inputs to WEPS are meteorological data, soil data, and crop management practices. These data, at a 1 km × 1 km grid cell resolution, are the basic input data for running the spatially distributed model. The climatic data from a three-year period were stochastically generated based on statistical representations of past meteorological measurements from stations in the region and were used for initializing WEPS, and then a three-day set of meteorological data corresponding with historical dust storm events were selected for simulation by WEPS of wind erosion of cropland in the state of Washington. The crop management data were selected based on the land use and USDA Natural Resources Conservation Service (NRCS) crop management zones, and the soil data were derived from the NRCS SSURGO database. We aggregated the outputs from 1 km × 1 km grid cells into 12 km × 12 km grid cells for easier visualization and then mapped the total surface soil erosion, suspension, and PM₁₀ emissions for each 12 km × 12 km grid cell. This study shows that WEPS can be successfully extended to run from one field grid cell to multiple field grid cells, and the model can identify regions with high potential for soil erosion by wind. It also demonstrates that WEPS can be used for real-time monitoring of soil erosion and air quality in a large region if actual and forecast weather inputs are available.

福建省长汀县河田水土流失区植被覆盖度变化及其热环境效应

南方红壤典型水土流失区——福建省长汀县河田盆地区的大片山地曾由于植被稀少、山岭裸露、气候炎热,而被称之为"火焰山"。通过20多年的水土流失治理,该区的生态环境有了很大的改善。利用遥感技术,计算了长汀县河田盆地区在1988-2010年间的植被覆盖度变化及其伴随的地表温度变化。结果表明,通过近22a的水土流失治理,该区的平均植被覆盖度有了明显的升高,从1988年的48.83%上升到2010年的59.78%;而同期盆地内外的温度差异也随之下降,盆地裸露区和周边地区的温差降低了近1 ℃。定量研究表明,河田盆地区的植被覆盖度每增加10%,可降低地表温度0.6-1℃。;Soil erosion has caused severe ecological problems in China. Being a typical reddish soil erosion region in southtern China, the hilly areas of the Hetian Basin in County Changting, Fujian province, have been called flame mountainous area, due to lack of vegetation covers, extensively exposed bare soils, and hot weathers. After more than 20 years of soil-loss treatment, the local ecosystem and environment have been greatly improved. This study used remote sensing techniques and four scenes of Landsat Thematic Mapper (TM) images, enquired in 1988, 1998, 2004, and 2010, to study the fractional vegetation cover changes and accompanied land surface temperature variations in the Hetian basinal area during the period from 1988 to 2010. Two remote-sensing based models for estimating fractional vegetation cover have been compared in order to select a suitable model for the retrieval of the fractional vegetation cover in the study area. The two models compared are the Carlson-Ripley and Gutman-Ignatov models. The comparative analysis confirmed that the Carlson-Ripley model had a higher accuracy than the Gutman-Ignatov model as it has a lower systematic error value. Therefore, the Carlson-Ripley model was used to retrieve the fractional vegetation cover for the study area. While, the land surface temperature change during the study period was evaluated through the temperature difference between the areas inside and outside the basin in each study year. The results indicate that the 22-year effort for the treatment of the soil loss in the Hetian basinal area has resulted in the notably increase in fractional vegetation cover in the area, averagely from 48.83% in 1988 to 59.78% in 2010. Meanwhile, the difference in land surface temperature between the areas inside and outside the basin has also been reduced from 3.39℃ in 1988 to 2.48℃ in 2010, almost 1℃ declined. This suggests a lowering of the temperature in the area inside the basin. Obviously, the increase in fractional vegetation cover was accompanied with the lowering of regional temperature. Spatial and temporal analysis indicates that the changes in both fractional vegetation cover and land surface temperature mainly took place in the areas inside the Hetian Basin, while the areas outside the basin were rather consistent either in fractional vegetation cover or in land surface temperature. Quantitatively analysis suggests that each 10% increment in fractional vegetation cover would result in the lowering of local land surface temperature approximately by 0.6 to 1℃ based on regression models of the four study years.

生态植被建设对黄土高原农林复合流域景观格局的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 生态植被建设对黄土高原农林复合流域景观格局的影响 DOI: 10.5846/stxb201306071389 作者: 作者单位: 北京林业大学水土保持学院,北京林业大学水土保持学院,北京林业大学水土保持学院,北京林业大学水土保持学院 作者简介: 通讯作者: 中图分类号: F321.1 基金项目: 国家自然基金青年科学基金项目(41001362);水利部黄土高原水土流失过程与控制重点实验室开放课题基金项目(201301) Impact of ecological vegetation construction on the landscape pattern of a Loess Plateau Watershed Author: Affiliation: School of Soil and Water Conservation,Beijing Forestry University,Beijing,;China,School of Soil and Water Conservation,Beijing Forestry University,Beijing,;China,School of Soil and Water Conservation,Beijing Forestry University,Beijing,;China,School of Soil and Water Conservation,Beijing Forestry University,Beijing,;China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:自1999年以来,黄土高原大规模地实施了退耕还林工程,生态环境呈显著恢复态势。采用2002年和2008年两期Spot5遥感影像,评估了退耕还林工程实施前后黄土高原典型农林复合流域土地利用与景观格局的动态变化。结果表明:在退耕还林工程实施的驱动下,流域土地利用变化剧烈,总变化率高达36.77%,主要变化的土地利用类型包括耕地、果园、幼林地、林地等。28.95%的耕地转为其他土地利用类型,其中48.83%转为果园,44.69%转为幼林地。景观格局变化呈明显的空间分布规律,山腰缓坡区以转化为果园为主,中、高海拔多转化为幼林地。退耕后流域生态景观得以优化,呈现良好发展态势。 Abstract:Due to loose soil property and sparse vegetation coverage, the Loess Plateau is a famous soil erosion region in China or even the world. Although widespread ecological restoration efforts have been devoted in past decades, little progress could be seen in the loess region as a result of its unique natural environments. The ecological environment has not been significantly restored until 1999 with the introduction of the Grain for Green Project. As the largest program in history to restore ecological environment, this project has attracted the participation of huge number of farmers. Furthermore, it has involved the most extensive area and the largest amount of domestic investment and as a result, the degraded ecological environment has been gradually restored. With the implementation of the project, it is expected the land use/landscape has been changed accordingly. Prior studies have widely investigated the spatial-temporal dynamics and their driving forces of landscape patterns in medium-to-large watersheds by analyzing Landsat TM remote sensing data. In contrast, studies on landscape patterns in small watersheds through high-resolution remote sensing images are lacking, in particular on the land use dynamics resulted from various ecological restoration projects. Up to now, the Grain for Green projects has been implemented for more than 10 years, and it is now in the benefit consolidation phase. Therefore, an urgent need at present is to quantitatively evaluate the impacts of the ecological restoration project on land use change and landscape patterns through remote sensing and GIS techniques, with which to provide guidelines for future policies and decision making. Based on the Luoyugou watershed in Tianshui (Gansu Province), this study evaluated the dynamic changes of land use and landscape patterns between 2002 and 2008 by analyzing Spot5 remote sensing images. The results show that its land use and landscape patterns have been substantially changed due to the implementation of the Grain for Green project, with a total change of 36.77%. Major changed land use categories were cropland, orchards, young forest plantation, and forestland. In particular, 28.95% of the cropland had been converted to other land use patterns during the study period, of which, 48.83% had been converted to orchards and 44.69% to young forest plantation. The changes of landscape patterns showed an obvious spatial distribution, with most of the gentle slope regions being converted to orchards and the medium-to-high altitudes mainly to young forest plantation regions. After the implementation of the Grain for Green project, the ecological landscape in the Luoyugou watershed has been greatly improved, indicating a good sign for future development. 参考文献 相似文献 引证文献

Late Quaternary soil erosion and landscape development in the Apennine region (central Italy)

This study on past soil erosion processes focuses on a catchment located in a mountainous sector of the Central Apennines, 60 km northeast of Rome. Humans are known to have interacted with the landscape in this region at least since the early Iron Age. The area is highly sensitive to climatic changes and human intervention and thus is susceptible to soil erosion. The environmental impact of past human activities has been examined by geomorphological and sedimentological investigations and supported by modelling operations.Percussion drillings in the floodplains reveal up to 10 m thick alluvial deposits. Combined sedimentological and geomorphological analysis suggests that the total sediment volume of the valley infill totals about 300,000 m3 of sediments. Radiocarbon dating documents that this alluvial sedimentation started during the sub-Atlantic period (between the 1st and 2nd centuries BC) and coincides with a shift from a flood-quiescent to a flood-prone phase. According to historical sources, the flood phase correlates chronologically with the Roman occupation of the area, when they practiced extensive logging in their territories. GIS modelling operations show a loss of soil surface of about 71 cm on average for the entire catchment (1,600,000 m3 loss of soil), if long-term land exploitation for wood supply is assumed. The modeling showed that approximately 80% of the eroded soil has been fluvially transported out of the catchment, so the present alluvial plains may represent only about 20% of the overall lost soil mass.

Estimating Medium-Term Soil Erosion Rates under Different Types of Land Use in Red Soil Region of Jiangxi, Southern China Using &lt;sup&gt;137&lt;/sup&gt;Cs Technique

Soil erosion has been recognized as one of the major environmental problem in red soil region of southern China. The spatial variation of soil erosion was studied using 137Cs technique at three sites (site A, site B, site C) under different type of land use in Jiangxi province. To understand the spatial distribution of soil erosion is important for taking proper soil and water conservation measures. 280 samples were collected at three sites. Medium-term average soil erosion rates estimated for dry farmland is 83.1 kg ha-1 a-1 at site A, and that for paddy fields with terraces on the middle-lower slope is 79.2 kg ha-1 a-1 at site B. Among the uncultivated lands, the average soil erosion rate of bare land is 3700 kg ha-1 a-1 on the upper slope at site A, that of woodland covered with masson pines on the upper slope is 1106 kg ha-1 a-1 at site B and that of economic forest that covered with orchard is 1380.5 kg ha-1 a-1 at site C. On the whole, the soil erosion rate of cultivated land is lower than that of uncultivated land. Bare land, woodland and orchard are the three main sources of soil erosion in red soil region of southern China. Protective measures of cultivated land, such as terraces, field ridge and ditch beside the land, had been demonstrated effectively in controlling soil erosion. The findings provide more information on agricultural land under different type of land use and managed measures which play an important role in controlling the soil loss in Southern China to a certain degree.

Increasing occurrence of high-intensity rainstorm events relevant for the generation of soil erosion in a temperate lowland region in Central Europe

Summary Rainfall times series with a high temporal resolution of 1 min for the Emscher–Lippe catchment area were analysed for trends in regard to erosion-relevant storm events with intensities larger than 0.3 mm/min (>20 mm/h) for the last 70 years using the Mann–Kendall test. The analysis data showed for all investigated stations an increase of rainstorm events with erosion-relevant rainfall intensities; the trend was more pronounced over the last 35 years and was shown to be statistical significant for a critical zone with rainfall characteristics of: intensity iRain = 0.3–0.7 mm/min, duration tRain = 2–10 min and depth hRain = 1–3 mm. The increase of rainstorm events over the last 35 years was more pronounced in the summer season (July–September), but increases were detected also in the other seasons. The high-intensity storm events occured only ca. 4–15 times/year; the estimated trend increases of up to 0.5 events/year could therefore result in a multiplication of the occurrence of these storm events within only a few decades. This study has shown for the first time that the rainfall regime for temperate lowland regions in Germany has changed within its erosion-relevant spectrum over the last couple of decades. Parallel to the changes in the rainfall regime, increases in the annual and seasonal average temperature and changes in the occurrence of circulation patterns responsible for the generation of high-intensity storms were found, however not in the occurrence of thunderstorms. A climate-change driven increase of rain storm events over the last couple of decades and a potential future continuation of this trend may have several adverse effects for the study area and potentially for a larger region in Central Europe, for example an increase of soil erosion on slopes, the depletion of soil nutrients, an increased transport of nutrients and contaminants attached to sediment particles, their transfer into surface water bodies and consequential negative effects on stream habitats.

Monitoring of soil erosion in Cappadocia region (Selime-Aksaray-Turkey)

A fairy chimney is a conical rock formation, typically found in the Cappadocia region of Turkey. The geology of areas where fairy chimneys exist typically comprise a thick layer of tuff, covered by a thin layer of basalt or other volcanic rocks that are more resistant to erosion than the underlying tuff. Fairy chimneys are formed where a small cap or boulder of the original basalt remains, protecting a cone of tuff beneath it from erosion. Eventually, the tuff will be undercut to the extent that the cap falls off, and the remaining cone is then quickly eroded. In this study, the formation of fairy chimneys in the Cappadocia region was examined by investigating the surface soil erosion. A study area was selected and then scanned at five different times by a geodetic robotic total station at 40 cm horizontal and vertical intervals. The volumes of the study area were calculated from the same height and erosion was calculated from the volume differences indicated by the data. The relationship between erosion and meteorological data was analyzed, and showed that erosion had increased due to climatic conditions, particularly from the effect of rainfall.

Sediments deposition due to soil erosion in the watershed region of Mangla Dam

Soil erosion is the most important reason of sedimentation load of water reservoirs in the world. In Pakistan, Mangla dam is one of the most important water reservoirs used for the production of electricity and for the supply of water for irrigation purposes. However, the capacity of Mangla dam reservoir has reduced by more than 20% since its construction. This study highlights the impact of rainfall on soil erosion and consequently on sedimentation deposition in Mangla dam reservoir. Sedimentation, annual rainfall, and normal rainfall data of 39 years were used in this study. Shuttle Radar Topographic Mission data were used to calculate the total drainage area of the Mangla watershed region. The sedimentation data of Mangla reservoir from 1967 to 2005 were retrieved from Water and Power Development Authority in Pakistan. The meteorological observatories in the Mangla watershed region are identified. Annual rainfall data from 1967 to 2005 for the meteorological observatories in the Mangla watershed regions were retrieved from Pakistan Meteorological Department (PMD). In addition, normal rainfall data for the years 1949 to 1978 and for the years 1979 to 2008 were also retrieved from PMD. The impact of annual rainfall is observed on sedimentation load in Mangla dam. The correlation coefficient between annual rainfall and sedimentation load is 0.94. This study shows that with an increase in rainfall, the soil erosion of the area increases which subsequently is responsible for the increase in the rate of sedimentation load in Mangla dam. This study further demonstrates that better soil management can reduce the sedimentation load in the Mangla reservoir.

Soil erosion in the Three Gorges Reservoir area

Spatial and temporal change in soil erosion in the Three Gorges Reservoir area since the water storage of the reservoir began filling to 135 m in 2003 is poorly understood. Using a modified soil erosion model, this study quantifies and analyses change in the extent and intensity of soil erosion in the region from 2000 to 2008. MODIS-NDVI remote sensing data (with 250 m spatial resolution) are used in the modelling and analysis of the study. The total amount, area, and intensity of soil erosion in the reservoir region presented a declining trend from 2000 to 2008. Yet there was an anomaly in the trend, in which extreme soil erosion occurred in 2003 and lasted until 2005. The average volume of soil erosion per year decreased by 4.10 × 106 t and the mean area of land experiencing soil erosion reduced by 1129.6 km2 from the pre-storage period (2000–02) to post-storage period II (2006–08). Land suffering soil erosion at high, very high, and severe levels mainly comprises forest and cropland on slopes with gradients ≥15° and is largely distributed in the eastern and south-western sections of the reservoir area. Land experiencing soil erosion at slight or moderate levels mainly involves cropland and forest on slopes with gradients ≥10° in the central section of the reservoir area. The impact of the Three Gorges Project on soil erosion since 2000 has been mainly mediated through three mechanisms: near-resettlement of rural and urban people; increased frequency and severity of geological hazards induced by rising storage of the reservoir; and implementation of ecological projects in the region. Through the former two mechanisms, soil erosion in the affected communities has been exacerbated, while the ongoing ecological projects appear to offset both the extent and intensity of soil erosion in the reservoir region. Other important factors influencing soil erosion include urban reconstruction and expansion, varying intensity of precipitation, and soil degradation.

Response of runoff and soil loss to reforestation and rainfall type in red soil region of southern China

To evaluate the long-term effects of reforestation types on soil erosion on degraded land, vegetation and soil properties under conventional sloping farmland (CSF) and three different reforestation types including a Pinus massoniana secondary forest (PSF), an Eucommia ulmoides artificial economic forest (EEF) and a natural succession type forest (NST), were investigated at runoff plot scale over a six-year period in a red soil region of southern China. One hundred and thirty erosive rainfall events generating runoff in plots were grouped into four rainfall types by means of K-mean clustering method. Erosive rainfall type I is the dominant rainfall type. The amount of runoff and the soil loss under erosive rainfall type III were the most, followed by rain-fall type II, IV and I. Compared with CSF treatment, reforestation treatments decreased the average annual runoff depth and the soil loss by 25.5%-61.8% and 93.9%–96.2% during the study period respectively. Meanwhile, runoff depth at PSF and EEF treatments was significantly lower than that in NST treatment, but no significant difference existed in soil erosion modulus among the three reforestation treatments. This is mainly due to the improved vegetation properties (i.e., vegetation coverage, biomass of above- and below-ground and litter-fall mass) and soil properties (i.e., bulk density, total porosity, infiltration rate and organic carbon content) in the three reforestation treatments compared to CSF treatment. The PSF and EEF are recommended as the preferred reforestation types to control runoff and soil erosion in the red soil region of southern China, with the NST potentially being used as an important supplement.

Land abandonment, landscape evolution, and soil erosion in a Spanish Mediterranean mountain region: The case of Camero Viejo

AbstractThe Spanish Mediterranean mountains have played an important social and economic role for many centuries. However, since the 1950s these regions have been considered of little economic interest, and this has led to the abandonment of villages, reduced productive activity, and significant changes in the landscape. In the last 50 years the Camero Viejo region (Iberian System, northeast Spain) has been subject to these changes, and was selected as our study area. Landscape evolution and soil erosion, as a result of agricultural abandonment, were studied using different analysis techniques: photointerpretation, geographic information systems and rainfall simulation. The results showed that a large proportion of previously cultivated land has been subject to plant recolonization processes. From 1956 to 2001, woodlands area increased from 10·1 per cent to 37 per cent, and scrubland increased from 42 per cent to 60 per cent. Changes in landscape structure in the same period suggest that the Camero Viejo is in a transitional stage from a highly humanized landscape to a more natural landscape. Although plant cover expansion is evident on most Camero Viejo hillslopes, in some terraced areas erosion processes are active. The generalized abandonment of agricultural terraces has favored the collapse of the stone walls of the terraces, with sliding of the soil. Surface runoff on abandoned terraces is also important. These erosion processes are related to the hydrological functioning of slopes following abandonment, neglect, and in some areas the intensification of grazing. Terrace destruction has a negative impact on the landscape and represents the loss of fertile soils. Landscape diversity should be preserved as an essential element of the economic potential of the Camero Viejo. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Soil erosion changes over the past five decades in the red soil region of Southern China

This paper reports the dynamic changes of soil and water loss in the red soil region of Southern China since the 1950s. The red soil region covers eight provinces: Jiangxi, Zhejiang, Fujian, Anhui, Hubei, Hunan, Guangdong and Hainan. From the 1950s to 1986, the annual rate of soil erosion increased by 3.4%. From 1986 to 1996 and from 1996 to 2000, the annual rates of soil erosion decreased by 2.0% and 0.32%, respectively. Field surveys showed that from 2000 to 2005, the area of soil and water loss decreased annually by 1.2%. This decrease was a result of large-scale erosion control activities across China. Although the eroded soil has been restored, the restoration process is very slow and full restoration will take a long time. Our report suggests that controlling soil and water loss is a challenging task, and additional measures must be taken to effectively control the soil erosion in the red soil region.