A large number of loose piles formed by mountain hazards are highly susceptible to hydraulic erosion under rainfall conditions.The use of ecological substrate materials for erosion control and ecological restoration o...A large number of loose piles formed by mountain hazards are highly susceptible to hydraulic erosion under rainfall conditions.The use of ecological substrate materials for erosion control and ecological restoration of gravel soil slopes has become a current research hotspot and the study difficulty.The post-earthquake slump accumulation gravel soil in Jiuzhaigou was selected as the research object,and the self-developed modified glutinous rice-based material was used to reinforce the gravel soil.The variable slope flume erosion test and rainfall simulation test were carried out to study the water erosion resistance of the material reconstructed soil under the influence of runoff erosion and raindrop splash erosion.The results show that:As the material content reached 12.5%,the reconstructed soil did not disintegrate after 24 hours of immersion,the internal friction angle was increased by 42.26%,and the cohesion was increased by 235.5%,which played a significant reinforcement effect.In the process of slope erosion,the soil rill erodibility parameter Kr was only 3‰ of the gravel soil control group,the critical shear force τ increased by 272%,and the soil erosion resistance was significantly improved.In the process of rainfall and rainfall on the slope,the runoff intensity of the reconstructed soil was stable,and the ability to resist runoff erosion and raindrop splash erosion was enhanced.The maximum value of soil loss rate on different slope slopes is 0.02-0.10 g·m^(-2)s^(-1),which is significantly lower than that of the control group and has better erosion reduction effect.展开更多
Both tillage erosion and water erosion are severe erosional forms that occur widely on sloping agricultural land.However,previous studies have rarely considered the process of landform change due to continuous simulat...Both tillage erosion and water erosion are severe erosional forms that occur widely on sloping agricultural land.However,previous studies have rarely considered the process of landform change due to continuous simulation experiments of alternating tillage erosion and water erosion.To identify such changes,we applied a scouring experiment(at a 60 L min-1 water discharge rate based on precipitation data from the local meteorological station and the catchment area in the Yuanmou County,Yunnan Province,China)and a series of simulated tillage experiments where plots were consecutively tilled 5,10,and 15 times in rotation(representing 5 yr,10 yr,and 15 yr of tillage)at slope gradients of 5°,10°,and 20°.Close-range photogrammetry(CRP)employing an unmanned aerial vehicle(UAV)and a real-time kinematic global positioning system(RTK-GPS)was used to measure landform changes,and highresolution digital elevation models(DEMs)were generated to calculate net soil loss volumes.Additionally,the CRP was determined to be accurate and applicable through the use of erosion pins.The average tillage erosion rates were 69.85,131.45,and 155.34 t·hm-2·tillage pass-1,and the average water erosion rates were 1892.52,2961.76,and 4405.93 t·hm-2·h-1 for the 5°,10°,and 20°sloping farmland plots,respectively.The water erosion rates increased as tillage intensity increased,indicating that tillage erosion accelerates water erosion.Following these intensive tillage treatments,slope gradients gradually decreased,while the trend in slope gradients increased in runoff plots at the conclusion of the scouring experiment.Compared to the original plots(prior to our experiments),interactions between tillage and water erosion caused no obvious change in the landform structure of the runoff plots,while the height of all the runoff plots decreased.Our findings showed that both tillage erosion and water erosion caused a pseudo-steady-state landform evolutionary mechanism and resulted in thin soil layers on cultivated land composed of purple soil in China.展开更多
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 an...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 87.6103 km^(2) 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 2184 t/(km^(2) a).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 activities4vegetation degradation4rainfall and climate change4topography and soil erodibility4tectonics 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 2.07×10^(3) km^(2) 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.&2015 International Research and Training Center on Erosion and Sedimentation and China Water and Power Press.Production and Hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).展开更多
Water erosion process induces differences to the nitrogen(N)functional microbial community structure,which is the driving force to key N processes at soil-water interface.However,how the soil N trans-formations associ...Water erosion process induces differences to the nitrogen(N)functional microbial community structure,which is the driving force to key N processes at soil-water interface.However,how the soil N trans-formations associated with water erosion is affected by microorganisms,and how the microbial respond,are still unclear.The objective of this study is to investigate the changes of microbial diversity and community structure of the N-cycle function microorganisms as affected by water erosion under application of organic manure and straw cover.On the basis of iso-nitrogen substitution,four treatments were set up:1)only chemical fertilizer with N 150 kg ha^(-1),P2O560 kg ha^(-1) and K2O 90 kg ha^(-1)(CK);the N was substituted 20%by 2)organic manure(OM);3)straw(SW);and 4)organic manure+straw(1:1)(OMSW).The results showed that applying organic manure and straw to sloping farmland can increase soil N contents,but reduce runoff depth,Kw,sediment yield and N loss,especially in the OMSW.Straw cover and straw+organic manure increased the diversity(Chao1)of nitrifier(AOB),and both diversity and uniformity(Shannon)of denitrifier(nirK/S)were increased in the OMSW.All erosion control mea-sures reduced N-fixing bacteria diversity and increased their uniformity,and the combined application of organic manure and straw cover was a better erosion control measure than the single application of them.Improved soil chemistry and erodibility were the main drives for the changes of N-functional microbial community structure and the appearance of dominant bacteria with different organic materials.展开更多
To quantify water erosion rates and annual soil loss in mountainous areas,two different empirical models were used to estimate the effects of soil erosion in a small mountain basin,the Guerna Creek watershed,located i...To quantify water erosion rates and annual soil loss in mountainous areas,two different empirical models were used to estimate the effects of soil erosion in a small mountain basin,the Guerna Creek watershed,located in the Central Southern Alps(Northern Italy).These two models,Revised Universal Soil Loss Equation(RUSLE) and Erosion Potential Model(EPM),were implemented in a Geographical Information System,accounting for the geographical,geomorphological,and weather-climate parameters,which are fundamental to evaluating the intensity and variability of the erosive processes.Soil characterization was supported by laboratory analysis.The results(computed soil loss of 87 t/ha/year and 11.1 m^(3)/ha/year,using RUSLE equation and EPM method,respectively,and sediment yield of 7.5 m^(3)/ha/year using EPM method) were compared to other studies reported in the literature for different case studies with similar topographic and climatic features,as well as to those provided by the European Soil Data Centre(ESDAC).In both cases,the agreement was satisfactory,showing consistency of the adopted procedures to the parametrization of the physical processes.展开更多
The aim of this study is to map the areas exposed to water erosion risks in the High Atlas Mountains of Morocco around the Hassan-I dam.The methodology is based on the analysis of the water power index(WPI)as a hydrol...The aim of this study is to map the areas exposed to water erosion risks in the High Atlas Mountains of Morocco around the Hassan-I dam.The methodology is based on the analysis of the water power index(WPI)as a hydrological parameter,the vegetation cover,and the litho-logical units.The WPI was derived from a Digital Elevation Model(DEM)and the litho-logical units and vegetation cover were derived from Advanced Land Imager sensor on the Earth Observing-1 satellite platform.The image was corrected from radiometric and atmospheric effects,and geometrically rectified using a DEM and grounds control points.These variables were integrated in a Geographical Information Systems environment,and Multi-Criteria Analyses were used to derive the water erosion risks map pointing out the most exposed areas requiring the implementation of suitable conservation measures.The validation of the obtained results shows the simplicity and the potential of this approach for water erosion risks mapping.展开更多
The revised Morgan,Morgan and Finney(rMMF)water erosion model calculates annual surface runoff and soil loss from field-sized areas.The original version of the rMMF is neither suited to calculate water erosion along i...The revised Morgan,Morgan and Finney(rMMF)water erosion model calculates annual surface runoff and soil loss from field-sized areas.The original version of the rMMF is neither suited to calculate water erosion along irregular hillslopes,nor capable to allow infiltration of once generated surface runoff at places where the runoff speed slows down,and infiltration could occur under natural conditions.The aim of this article is to describe a new hillslope version of the rMMF model that allows infiltration of surface runoff,and to show examples of soil erosion modelling along real and hypothetical hillslopes.The new hillslope version(hMMF)splits the entire hillslope into a number of sections that have individual properties,such as slope angle,slope length,soil properties and vegetation characteristics.The surface runoff along the slope is calculated by summing the volume of surface runoff generated in a particular section with the surface runoff coming from the immediate upsiope section.The related sediment transport is calculated for each section using the calculated detachment for the section,the sediment coming from the upsiope section and the transport capacity.A new variable is introduced to account for infiltration of surface runoff and allows simulating the effects of soil and water conservation structures on water erosion.The model was tested using measured data from plots in Africa,Asia,the US and Europe,as well as for a surveyed hillslope in Tunisia(Barbara watershed).Overall,the performance of the hMMF was reasonable for surface runoff and poor for soil loss when recommended input variable values are used.Calibration of the model resulted in a good performance,which shows the capability of the hMMF model to reproduce measured surface runoff and erosion amounts.In addition,realistic water erosion patterns on hillslopes with soil and water conservation can be simulated.展开更多
Our work focuses on the assessment of trends,erosion states and causal risk factors for soil erosion of the Asfalou watershed through the use of the Priority Actions Program/Regional Activity Center(PAP/RAC).This qual...Our work focuses on the assessment of trends,erosion states and causal risk factors for soil erosion of the Asfalou watershed through the use of the Priority Actions Program/Regional Activity Center(PAP/RAC).This qualitative study model for water erosion makes it possible to assess susceptibility and determine potential fragile areas in order to diagnose the state of soil degradation.We adopted the PAP/RAC crossed matrices,the geographic information system(GIS)and remote sensing(RS)to develop the classical modelling.This method is based on three main approaches:predictive,descriptive and integration.Introducing soil types,slope length(LS)and climatic factors into our model,including rainfall erosivity(R),slope exposure,soil moisture index(SMI)and land surface temperature(LST),improved the reli-ability of our model.The correlation analysis identified these factors that explain erosion states and the risk of soil erosion.The coefficients of determination(R2)of the various erosive states resulting from the modified PAP/RAC approach explain respectively 98.30%,77%and 49.3%of the observed variability of the erosive states.These factors provide information on the current state of soil degradation depending on the degree of influence of the different factors that control erosion.The descriptive approach has shown that soil loss manifests itself in different forms,whether for sheet erosion(L)and ravines(C1)succes-sively affecting 79.95%and 17.84%of the land.The integration approach identifies factors and areas requiring intervention to counter the effects of soil erosion in the Asfalou watershed effectively and sustainably.展开更多
Soil erosion is one of the most serious environmental issues constraining the sustainable development of human society and economies.Soil compound erosion is the result of the alternation or interaction between two or...Soil erosion is one of the most serious environmental issues constraining the sustainable development of human society and economies.Soil compound erosion is the result of the alternation or interaction between two or more erosion forces.In recent years,fluctuations and extreme changes in climatic factors(air temperature,precipitation,wind speed,etc.)have led to an increase in the intensity and extent of compound erosion,which is increasingly considered in soil erosion research.First,depending on the involvement of gravity,compound erosion process can be divided into compound erosion with and without gravity.We systematically summarized the research on the mechanisms and processes of alternating or interacting soil erosion forces(wind,water,and freeze-thaw)considering different combinations,combed the characteristics of compound erosion in three typical regions,namely,high-elevation areas,high-latitude areas,and dry and wet transition regions,and reviewed soil compound erosion research methods,such as station observations,simulation experiments,prediction models,and artificial neural networks.The soil erosion model of wind,water,and freeze-thaw interaction is the most significant method for quantifying and predicting compound erosion.Furthermore,it is proposed that there are several issues such as unclear internal mechanisms,lack of comprehensive prediction models,and insufficient scale conversion methods in soil compound erosion research.It is also suggested that future soil compound erosion mechanism research should prioritize the coupling of compound erosion forces and climate change.展开更多
Soils in the hydro-fluctuation belts of the reservoirs are most highly influenced by the special hydro-conditions and reservoir operation,leading to unique soil erosion process and largely accelerate soil erosion inte...Soils in the hydro-fluctuation belts of the reservoirs are most highly influenced by the special hydro-conditions and reservoir operation,leading to unique soil erosion process and largely accelerate soil erosion intensity.The present study aimed to estimate soil erosion rate in the hydro-fluctuation belt of the Pubugou Reservoir,Southwest China,based on the framework of Universal Soil Loss Equation(USLE).An attempt has been made to modify the original USLE by including the reservoir water erosivity(W),a new factor into the model.Soil erosion rate from different land use types were quantitatively estimated,using the USLE and the modified USLE respectively.Field observation showed that soil erosion rate in dry farmland,bare land and grassland was 4700,44600 and 5050 t/km2,respectively.The erosion rate assessed by the modified USLE was closely related to that recorded from the field monitoring data.The findings of this study clearly highlight the importance of inclusion of the W factor to the original USLE model while assessing soil erosion in the reservoir hydro-fluctuation belt.展开更多
The watershed of the Arbaa Ayacha River is an environment favorable to the development of the phenomena of water erosion as a result of its topographic features, lithological and climate. Therefore it has been the sub...The watershed of the Arbaa Ayacha River is an environment favorable to the development of the phenomena of water erosion as a result of its topographic features, lithological and climate. Therefore it has been the subject of evaluation of states erosive and of different causal factors of the risk of erosion by adaptation of cross-matrices based on directives PAP/RAC (Priority Actions Programme/Regional Activity Centre) [1]. This method is based on three approaches. The predictive approach provides a synthetic map of the distribution of the erosive states, with 51% of the basin subjected to high risks. The descriptive mapping of the various forms of erosion shows an enormous extension of stripping and sheet erosion (91%), superficial gullies and moderately deep gullies are growing in view of the gathering of runoffs from upstream to the downstream. The superposition of the results of both predictive and descriptive approaches gives a consolidated map PAP/RAC whose analysis shows that soils’ loss throughout the basin is proportional to the increase of the major factors of water erosion according to the level of importance: The topographical factor—soil types—slope-lithology following a positive linear relationship, while the order of the parameters that are negative linear relationship is density of vegetation cover-land cover [2]. This same map gives maximal losses corresponding mainly to friable lithologic natural areas of badlands at the center of the basin which correspond to Tensift’s terraces [3]. In the downstream basin, the combined effect of deep ravines and banks sapements promotes high risk while in the upstream, the localized solifluxions and gravity screens participate in serious losses.展开更多
To improve soil carbon sequestration capacity,the full soil carbon cycle process needs to be understood and quantified.It is essential to evaluate whether water erosion acts as a net source or sink of atmospheric CO_(...To improve soil carbon sequestration capacity,the full soil carbon cycle process needs to be understood and quantified.It is essential to evaluate whether water erosion acts as a net source or sink of atmospheric CO_(2)at the basin scale,which encompasses the entire hydrological process.This study introduced an approach that combined a spatially distributed sediment delivery model and biogeochemical model to estimate the lateral and vertical carbon fluxes by water erosion at the basin scale.Applying this coupling model to the Dongting Lake Basin,the results showed that the annual average amount of soil erosion during 1980-2020 was 1.33×10^(8)t,displaying a decreasing trend followed by a slight increase.Only 12% of the soil organic carbon displacement was ultimately lost in the riverine systems,and the rest was deposited downhill within the basin.The average lateral soil organic carbon loss induced by erosion was 8.86×10^(11)g C in 1980 and 1.50×10^(11)g C in 2020,with a decline rate of 83%.A net land sink for atmospheric CO_(2)of 5.54×1011g C a^(-1)occurred during erosion,primarily through sediment burial and dynamic replacement.However,ecological restoration projects and tillage practice policies are still significant in reducing erosion,which could improve the capacity of the carbon sink for recovery beyond the rate of horizontal carbon removal.Moreover,our model enables the spatial explicit simulation of erosion-induced carbon fluxes using costeffective and easily accessible input data across large spatial scales and long timeframes.Consequently,it offers a valuable tool for predicting the interactions between carbon dynamics,land use changes,and future climate.展开更多
Climate,land use and land cover(LULC)changes are among the primary driving forces of soil loss.Decoupling their effects can help in understanding the magnitude and trend of soil loss in response to human activities an...Climate,land use and land cover(LULC)changes are among the primary driving forces of soil loss.Decoupling their effects can help in understanding the magnitude and trend of soil loss in response to human activities and ecosystem management.Here,the RUSLE model was applied to estimate the spatial-temporal variations of soil loss rate in the Three Gorges Reservoir(TGR)area during 2001-2015,followed by a scenario design to decouple the effects of climate and LULC changes.The results showed that increasing rainfall generated as much as 2.90×10^(7)t soil loss in the TGR area.However,such effect was offset by changes in LULC particularly afforestation,which retained about 1.10×10^(7)t soil annually.Other human activities such as dam development and urbanization aggravated soil loss by as much as 1.40×10^(6)t annually.Because of land use policies that favor economic development,distinct spatial variances of soil loss were observed in TGR area.Soil loss in some counties located downstream of the TGR area(i.e.,close to the dam)was more influenced by dam development,but soil loss in the other counties was more influenced by urbanization.As climate change(i.e.,increasing rainfall)did not affect plant performance in TGR area,our findings suggested that ecological restoration was more beneficial to curb the amount of soil loss caused by urbanization and dam construction.展开更多
The soils of Benin in general and those of the department of Zou, in particular, are highly degraded. This study aimed to evaluate the effectiveness of sustainable land management practices on soil erodibility in two ...The soils of Benin in general and those of the department of Zou, in particular, are highly degraded. This study aimed to evaluate the effectiveness of sustainable land management practices on soil erodibility in two villages in the Plateau of Abomey. Soil samples were collected on plots under Sustainable Land Management (SLM) measures (direct seeding, maize residue management and soybean-cereal rotation) and on their adjacent control. The soil samples were prepared and analyzed in laboratory to determine variables such as soil permeability, organic matter content, and particle size. Soil erodibility was determined as proposed by Wischmeier & Smith. The effect of SLM practices was significant (0.02) on soil permeability. On plots under SLM measurements, soil permeability is higher with an average of 93.97 mm/h at Folly and 82.43 mm/h at Hanagbo. SLM measurements significantly (0.04) added organic matter to the soil. The average organic matter of the plots under SLM measures in Folly varies from 0.73% to 1.39% while it varies from 0.49% to 0.73% in the control plots. In Hanagbo, the average organic matter of the plots under SLM measures varies from 1.86% to 2.48% against 1.41% to 1.66% for the control plots. Regarding soil erodibility, it was found that the influence of SLM measures is significant in both villages. In villages, direct seeding and maize residue management significantly (0.008) reduced soil erodibility compared to their adjacent controls, while the soybean-cereal rotation measure increased soil erodibility compared to plot witnesses. The average soil erodibility of plots under SLM measures varies by 0.21 t⋅h/Mj⋅mm at 0.38 t⋅h/Mj⋅mm in the village of Hanagbo and 0.25 t⋅h/Mj⋅mm at 0.38 t⋅h/Mj⋅mm in the village of Folly. It varies from 0.24 t⋅h/Mj⋅mm at 0.28 t⋅h/Mj⋅mm for the control plots at Hanagbo and 0.31 t⋅h/Mj⋅mm at 0.37 t⋅h/Mj⋅mm in Folly. These practices can therefore be used for the sustainable use of agricultural land.展开更多
Among the models used to assess water erosion,the RUSLE model is commonly used.Policy makers can act on cover(C-factor)and conservation practice(P-factor)to reduce erosion,with less costly action on soil surface chara...Among the models used to assess water erosion,the RUSLE model is commonly used.Policy makers can act on cover(C-factor)and conservation practice(P-factor)to reduce erosion,with less costly action on soil surface characteristics.However,the widespread use of vegetation indices such as NDVI does not allow for a proper assessment of the C-factor in drylands where stones,crusted surfaces and litter strongly influence soil protection.Two sub-factors of C,canopy cover(CC)and soil cover(SC),can be assessed from phytoecological measurements that include gravel-pebbles cover,physical mulch,annual and perennial vegetation.This paper introduces a method to calculate the C-factor from phytoecological data and,in combination with remote sensing and a geographic information system(GIS),to map it over large areas.A supervised classification,based on field phytoecological data,is applied to radiometric data from Landsat-8/OLI satellite images.Then,a C-factor value,whose SC and CC subfactors are directly derived from the phytoecological measurements,is assigned to each land cover unit.This method and RUSLE are implemented on a pilot region of 3828 km^(2) of the Saharan Atlas,composed of rangelands and steppe formations,and intended to become an observatory.The protective effect against erosion by gravel-pebbles(50%)is more than twice that of vegetation(23%).The C-factor derived from NDVI(0.67)is higher and more evenly distributed than that combining these two contributions(0.37 on average).Finally,priorities are proposed to decision-makers by crossing the synthetic map of erosion sensitivity and a decision matrix of management priorities.展开更多
Soil erosion prediction technology began over 70 years ago when Austin Zingg published a relationship between soil erosion(by water)and land slope and length,followed shortly by a relationship by Dwight Smith that exp...Soil erosion prediction technology began over 70 years ago when Austin Zingg published a relationship between soil erosion(by water)and land slope and length,followed shortly by a relationship by Dwight Smith that expanded this equation to include conservation practices.But,it was nearly 20 years before this work's expansion resulted in the Universal Soil Loss Equation(USLE),perhaps the foremost achievement in soil erosion prediction in the last century.The USLE has increased in application and complexity,and its usefulness and limitations have led to the development of additional technologies and new science in soil erosion research and prediction.Main among these new technologies is the Water Erosion Prediction Project(WEPP)model,which has helped to overcome many of the shortcomings of the USLE,and increased the scale over which erosion by water can be predicted.Areas of application of erosion prediction include almost all land types:urban,rural,cropland,forests,rangeland,and construction sites.Specialty applications of WEPP include prediction of radioactive material movement with soils at a superfund cleanup site,and near real-time daily estimation of soil erosion for the entire state of Iowa.展开更多
The effect of different rainfall patterns on surface runoff,infiltration and thus soil losses and sediment concentrations are still in the focus of current research.In most simulated rainfall experiments,pre-cipitatio...The effect of different rainfall patterns on surface runoff,infiltration and thus soil losses and sediment concentrations are still in the focus of current research.In most simulated rainfall experiments,pre-cipitation is applied at a fixed intensity for a fixed time.However,the impact of rainfall patterns on soil erosion processes may be different varying the rainfall duration and intensity that produces an event with similar rainfall erosivity values.Twenty-five rainfall events were applied on micro-scale runoff plots in a soil covered with corn straw to evaluate the sediment yield and runoff rates.The different rainfall types were composed by association of duration(Dur)and intensity(IP)with the same erosivity value.The Dur varied from 38 to 106 min and the IP varied from 75.0 to 44.6 mm h^(-1).The sediment yield varied from 1.89±1.26 g m^(-2) to 4.02±2.66 g m^(-2) and runoff ranged from 16.9±8.74 mm to 32.63±10.67 mm with highest rates occurring with high intensity and low duration.The highest rainfall intensity provides the maximum sediment yield(0.138 g m^(-2) min^(-1))and runoff rates(0.87 mm min^(-1)).The time to start surface runoff varied from 14 to 19.2 min and it was longer in treatments with longer durations and low precipitation intensity.No difference was found in the amount of sediments applying rain with the same erosivity and different associations of duration and intensity.However,the intensity and duration of the rain,with the same erosivity,altered the amount and time of runoff.In rainfall experiments with con-stant intensity and fixed time,the erosion rates depend on the duration of the applied rain.Therefore,the results of this study can contribute to the development of new perspectives in the design of water erosion experiments with simulated rain considering the duration,intensity and also the association of these variables to produce rainfall that delivery the same soil erosion capacity.展开更多
基金jointly funded by the Sichuan Provincial Natural Science Foundation of China (Grant No.2023NSFSC0378)the Jiuzhaigou Lake Swamp and River Ecological Restoration Research Project (N5132112022000246)。
文摘A large number of loose piles formed by mountain hazards are highly susceptible to hydraulic erosion under rainfall conditions.The use of ecological substrate materials for erosion control and ecological restoration of gravel soil slopes has become a current research hotspot and the study difficulty.The post-earthquake slump accumulation gravel soil in Jiuzhaigou was selected as the research object,and the self-developed modified glutinous rice-based material was used to reinforce the gravel soil.The variable slope flume erosion test and rainfall simulation test were carried out to study the water erosion resistance of the material reconstructed soil under the influence of runoff erosion and raindrop splash erosion.The results show that:As the material content reached 12.5%,the reconstructed soil did not disintegrate after 24 hours of immersion,the internal friction angle was increased by 42.26%,and the cohesion was increased by 235.5%,which played a significant reinforcement effect.In the process of slope erosion,the soil rill erodibility parameter Kr was only 3‰ of the gravel soil control group,the critical shear force τ increased by 272%,and the soil erosion resistance was significantly improved.In the process of rainfall and rainfall on the slope,the runoff intensity of the reconstructed soil was stable,and the ability to resist runoff erosion and raindrop splash erosion was enhanced.The maximum value of soil loss rate on different slope slopes is 0.02-0.10 g·m^(-2)s^(-1),which is significantly lower than that of the control group and has better erosion reduction effect.
基金supported by the National Key Research and Development Program of China(2017YFC0505102)the National Natural Science Foundation of China(No.41401313)+2 种基金the Major Science and Technology Program for Water Pollution Control and Treatment(2017ZX07101001)the Applied Basic Research Program of Sichuan(2018JY0034)the Major Science and Technology Projects in Sichuan Province(2018SZDZX0034)。
文摘Both tillage erosion and water erosion are severe erosional forms that occur widely on sloping agricultural land.However,previous studies have rarely considered the process of landform change due to continuous simulation experiments of alternating tillage erosion and water erosion.To identify such changes,we applied a scouring experiment(at a 60 L min-1 water discharge rate based on precipitation data from the local meteorological station and the catchment area in the Yuanmou County,Yunnan Province,China)and a series of simulated tillage experiments where plots were consecutively tilled 5,10,and 15 times in rotation(representing 5 yr,10 yr,and 15 yr of tillage)at slope gradients of 5°,10°,and 20°.Close-range photogrammetry(CRP)employing an unmanned aerial vehicle(UAV)and a real-time kinematic global positioning system(RTK-GPS)was used to measure landform changes,and highresolution digital elevation models(DEMs)were generated to calculate net soil loss volumes.Additionally,the CRP was determined to be accurate and applicable through the use of erosion pins.The average tillage erosion rates were 69.85,131.45,and 155.34 t·hm-2·tillage pass-1,and the average water erosion rates were 1892.52,2961.76,and 4405.93 t·hm-2·h-1 for the 5°,10°,and 20°sloping farmland plots,respectively.The water erosion rates increased as tillage intensity increased,indicating that tillage erosion accelerates water erosion.Following these intensive tillage treatments,slope gradients gradually decreased,while the trend in slope gradients increased in runoff plots at the conclusion of the scouring experiment.Compared to the original plots(prior to our experiments),interactions between tillage and water erosion caused no obvious change in the landform structure of the runoff plots,while the height of all the runoff plots decreased.Our findings showed that both tillage erosion and water erosion caused a pseudo-steady-state landform evolutionary mechanism and resulted in thin soil layers on cultivated land composed of purple soil in China.
基金supported by the National Science and Technology Support Plan(No.2014BAC15B03)the Recruitment Program of High Level Talents in Xinjiang,and the Young Talents Cultivation Program for Science and Technology Innovation in Xinjiang(No.2014731010).
文摘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 87.6103 km^(2) 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 2184 t/(km^(2) a).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 activities4vegetation degradation4rainfall and climate change4topography and soil erodibility4tectonics 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 2.07×10^(3) km^(2) 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.&2015 International Research and Training Center on Erosion and Sedimentation and China Water and Power Press.Production and Hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).
基金Financial support for this study was provided by the National Nature Science Foundation of China(No.41977072)the Special Fund for Agro-scientific Research in the Public Interest(201503119)the Agricultural Science and Technology Innovation Program(ASTIP).
文摘Water erosion process induces differences to the nitrogen(N)functional microbial community structure,which is the driving force to key N processes at soil-water interface.However,how the soil N trans-formations associated with water erosion is affected by microorganisms,and how the microbial respond,are still unclear.The objective of this study is to investigate the changes of microbial diversity and community structure of the N-cycle function microorganisms as affected by water erosion under application of organic manure and straw cover.On the basis of iso-nitrogen substitution,four treatments were set up:1)only chemical fertilizer with N 150 kg ha^(-1),P2O560 kg ha^(-1) and K2O 90 kg ha^(-1)(CK);the N was substituted 20%by 2)organic manure(OM);3)straw(SW);and 4)organic manure+straw(1:1)(OMSW).The results showed that applying organic manure and straw to sloping farmland can increase soil N contents,but reduce runoff depth,Kw,sediment yield and N loss,especially in the OMSW.Straw cover and straw+organic manure increased the diversity(Chao1)of nitrifier(AOB),and both diversity and uniformity(Shannon)of denitrifier(nirK/S)were increased in the OMSW.All erosion control mea-sures reduced N-fixing bacteria diversity and increased their uniformity,and the combined application of organic manure and straw cover was a better erosion control measure than the single application of them.Improved soil chemistry and erodibility were the main drives for the changes of N-functional microbial community structure and the appearance of dominant bacteria with different organic materials.
基金supported by MC s.r.l.,by the university research project (University of Brescia) Health and Wealth 2015“URBAID (Rigenerazione urbana assistita e integrata)”by the call H2020-SwafS-2016-17 Science with and for Society (European project:“SciShops”: Enhancing the Responsible and Sustainable Expansion of the Science Shops Ecosystem in Europe)。
文摘To quantify water erosion rates and annual soil loss in mountainous areas,two different empirical models were used to estimate the effects of soil erosion in a small mountain basin,the Guerna Creek watershed,located in the Central Southern Alps(Northern Italy).These two models,Revised Universal Soil Loss Equation(RUSLE) and Erosion Potential Model(EPM),were implemented in a Geographical Information System,accounting for the geographical,geomorphological,and weather-climate parameters,which are fundamental to evaluating the intensity and variability of the erosive processes.Soil characterization was supported by laboratory analysis.The results(computed soil loss of 87 t/ha/year and 11.1 m^(3)/ha/year,using RUSLE equation and EPM method,respectively,and sediment yield of 7.5 m^(3)/ha/year using EPM method) were compared to other studies reported in the literature for different case studies with similar topographic and climatic features,as well as to those provided by the European Soil Data Centre(ESDAC).In both cases,the agreement was satisfactory,showing consistency of the adopted procedures to the parametrization of the physical processes.
文摘The aim of this study is to map the areas exposed to water erosion risks in the High Atlas Mountains of Morocco around the Hassan-I dam.The methodology is based on the analysis of the water power index(WPI)as a hydrological parameter,the vegetation cover,and the litho-logical units.The WPI was derived from a Digital Elevation Model(DEM)and the litho-logical units and vegetation cover were derived from Advanced Land Imager sensor on the Earth Observing-1 satellite platform.The image was corrected from radiometric and atmospheric effects,and geometrically rectified using a DEM and grounds control points.These variables were integrated in a Geographical Information Systems environment,and Multi-Criteria Analyses were used to derive the water erosion risks map pointing out the most exposed areas requiring the implementation of suitable conservation measures.The validation of the obtained results shows the simplicity and the potential of this approach for water erosion risks mapping.
文摘The revised Morgan,Morgan and Finney(rMMF)water erosion model calculates annual surface runoff and soil loss from field-sized areas.The original version of the rMMF is neither suited to calculate water erosion along irregular hillslopes,nor capable to allow infiltration of once generated surface runoff at places where the runoff speed slows down,and infiltration could occur under natural conditions.The aim of this article is to describe a new hillslope version of the rMMF model that allows infiltration of surface runoff,and to show examples of soil erosion modelling along real and hypothetical hillslopes.The new hillslope version(hMMF)splits the entire hillslope into a number of sections that have individual properties,such as slope angle,slope length,soil properties and vegetation characteristics.The surface runoff along the slope is calculated by summing the volume of surface runoff generated in a particular section with the surface runoff coming from the immediate upsiope section.The related sediment transport is calculated for each section using the calculated detachment for the section,the sediment coming from the upsiope section and the transport capacity.A new variable is introduced to account for infiltration of surface runoff and allows simulating the effects of soil and water conservation structures on water erosion.The model was tested using measured data from plots in Africa,Asia,the US and Europe,as well as for a surveyed hillslope in Tunisia(Barbara watershed).Overall,the performance of the hMMF was reasonable for surface runoff and poor for soil loss when recommended input variable values are used.Calibration of the model resulted in a good performance,which shows the capability of the hMMF model to reproduce measured surface runoff and erosion amounts.In addition,realistic water erosion patterns on hillslopes with soil and water conservation can be simulated.
文摘Our work focuses on the assessment of trends,erosion states and causal risk factors for soil erosion of the Asfalou watershed through the use of the Priority Actions Program/Regional Activity Center(PAP/RAC).This qualitative study model for water erosion makes it possible to assess susceptibility and determine potential fragile areas in order to diagnose the state of soil degradation.We adopted the PAP/RAC crossed matrices,the geographic information system(GIS)and remote sensing(RS)to develop the classical modelling.This method is based on three main approaches:predictive,descriptive and integration.Introducing soil types,slope length(LS)and climatic factors into our model,including rainfall erosivity(R),slope exposure,soil moisture index(SMI)and land surface temperature(LST),improved the reli-ability of our model.The correlation analysis identified these factors that explain erosion states and the risk of soil erosion.The coefficients of determination(R2)of the various erosive states resulting from the modified PAP/RAC approach explain respectively 98.30%,77%and 49.3%of the observed variability of the erosive states.These factors provide information on the current state of soil degradation depending on the degree of influence of the different factors that control erosion.The descriptive approach has shown that soil loss manifests itself in different forms,whether for sheet erosion(L)and ravines(C1)succes-sively affecting 79.95%and 17.84%of the land.The integration approach identifies factors and areas requiring intervention to counter the effects of soil erosion in the Asfalou watershed effectively and sustainably.
基金supported by the key research and development and transformation project of Qinghai Province,China(2022-SF-173)the Second Tibetan Plateau Scientific Expedition and Research Program,China(2019QZKK0606)the National Natural Science Foundation of China(42101027).
文摘Soil erosion is one of the most serious environmental issues constraining the sustainable development of human society and economies.Soil compound erosion is the result of the alternation or interaction between two or more erosion forces.In recent years,fluctuations and extreme changes in climatic factors(air temperature,precipitation,wind speed,etc.)have led to an increase in the intensity and extent of compound erosion,which is increasingly considered in soil erosion research.First,depending on the involvement of gravity,compound erosion process can be divided into compound erosion with and without gravity.We systematically summarized the research on the mechanisms and processes of alternating or interacting soil erosion forces(wind,water,and freeze-thaw)considering different combinations,combed the characteristics of compound erosion in three typical regions,namely,high-elevation areas,high-latitude areas,and dry and wet transition regions,and reviewed soil compound erosion research methods,such as station observations,simulation experiments,prediction models,and artificial neural networks.The soil erosion model of wind,water,and freeze-thaw interaction is the most significant method for quantifying and predicting compound erosion.Furthermore,it is proposed that there are several issues such as unclear internal mechanisms,lack of comprehensive prediction models,and insufficient scale conversion methods in soil compound erosion research.It is also suggested that future soil compound erosion mechanism research should prioritize the coupling of compound erosion forces and climate change.
基金financially supported by the National Key Research and Development Program of China(Grant No.SQ2018YFD080041)the Sichuan Science and Technology Program(Grant No.2017SZ0188)。
文摘Soils in the hydro-fluctuation belts of the reservoirs are most highly influenced by the special hydro-conditions and reservoir operation,leading to unique soil erosion process and largely accelerate soil erosion intensity.The present study aimed to estimate soil erosion rate in the hydro-fluctuation belt of the Pubugou Reservoir,Southwest China,based on the framework of Universal Soil Loss Equation(USLE).An attempt has been made to modify the original USLE by including the reservoir water erosivity(W),a new factor into the model.Soil erosion rate from different land use types were quantitatively estimated,using the USLE and the modified USLE respectively.Field observation showed that soil erosion rate in dry farmland,bare land and grassland was 4700,44600 and 5050 t/km2,respectively.The erosion rate assessed by the modified USLE was closely related to that recorded from the field monitoring data.The findings of this study clearly highlight the importance of inclusion of the W factor to the original USLE model while assessing soil erosion in the reservoir hydro-fluctuation belt.
文摘The watershed of the Arbaa Ayacha River is an environment favorable to the development of the phenomena of water erosion as a result of its topographic features, lithological and climate. Therefore it has been the subject of evaluation of states erosive and of different causal factors of the risk of erosion by adaptation of cross-matrices based on directives PAP/RAC (Priority Actions Programme/Regional Activity Centre) [1]. This method is based on three approaches. The predictive approach provides a synthetic map of the distribution of the erosive states, with 51% of the basin subjected to high risks. The descriptive mapping of the various forms of erosion shows an enormous extension of stripping and sheet erosion (91%), superficial gullies and moderately deep gullies are growing in view of the gathering of runoffs from upstream to the downstream. The superposition of the results of both predictive and descriptive approaches gives a consolidated map PAP/RAC whose analysis shows that soils’ loss throughout the basin is proportional to the increase of the major factors of water erosion according to the level of importance: The topographical factor—soil types—slope-lithology following a positive linear relationship, while the order of the parameters that are negative linear relationship is density of vegetation cover-land cover [2]. This same map gives maximal losses corresponding mainly to friable lithologic natural areas of badlands at the center of the basin which correspond to Tensift’s terraces [3]. In the downstream basin, the combined effect of deep ravines and banks sapements promotes high risk while in the upstream, the localized solifluxions and gravity screens participate in serious losses.
基金supported by the National Natural Science Foundation of China(Grant No.U19A2047)the Natural Science Foundation of Hunan Province(Grant No.2023JJ20030)。
文摘To improve soil carbon sequestration capacity,the full soil carbon cycle process needs to be understood and quantified.It is essential to evaluate whether water erosion acts as a net source or sink of atmospheric CO_(2)at the basin scale,which encompasses the entire hydrological process.This study introduced an approach that combined a spatially distributed sediment delivery model and biogeochemical model to estimate the lateral and vertical carbon fluxes by water erosion at the basin scale.Applying this coupling model to the Dongting Lake Basin,the results showed that the annual average amount of soil erosion during 1980-2020 was 1.33×10^(8)t,displaying a decreasing trend followed by a slight increase.Only 12% of the soil organic carbon displacement was ultimately lost in the riverine systems,and the rest was deposited downhill within the basin.The average lateral soil organic carbon loss induced by erosion was 8.86×10^(11)g C in 1980 and 1.50×10^(11)g C in 2020,with a decline rate of 83%.A net land sink for atmospheric CO_(2)of 5.54×1011g C a^(-1)occurred during erosion,primarily through sediment burial and dynamic replacement.However,ecological restoration projects and tillage practice policies are still significant in reducing erosion,which could improve the capacity of the carbon sink for recovery beyond the rate of horizontal carbon removal.Moreover,our model enables the spatial explicit simulation of erosion-induced carbon fluxes using costeffective and easily accessible input data across large spatial scales and long timeframes.Consequently,it offers a valuable tool for predicting the interactions between carbon dynamics,land use changes,and future climate.
基金the National Key R&D Program of China(Grant No.2017YFC0505603)the Special Fund for Basic Scientific Research of Central Colleges,China University of Geosciences,Wuhan.
文摘Climate,land use and land cover(LULC)changes are among the primary driving forces of soil loss.Decoupling their effects can help in understanding the magnitude and trend of soil loss in response to human activities and ecosystem management.Here,the RUSLE model was applied to estimate the spatial-temporal variations of soil loss rate in the Three Gorges Reservoir(TGR)area during 2001-2015,followed by a scenario design to decouple the effects of climate and LULC changes.The results showed that increasing rainfall generated as much as 2.90×10^(7)t soil loss in the TGR area.However,such effect was offset by changes in LULC particularly afforestation,which retained about 1.10×10^(7)t soil annually.Other human activities such as dam development and urbanization aggravated soil loss by as much as 1.40×10^(6)t annually.Because of land use policies that favor economic development,distinct spatial variances of soil loss were observed in TGR area.Soil loss in some counties located downstream of the TGR area(i.e.,close to the dam)was more influenced by dam development,but soil loss in the other counties was more influenced by urbanization.As climate change(i.e.,increasing rainfall)did not affect plant performance in TGR area,our findings suggested that ecological restoration was more beneficial to curb the amount of soil loss caused by urbanization and dam construction.
文摘The soils of Benin in general and those of the department of Zou, in particular, are highly degraded. This study aimed to evaluate the effectiveness of sustainable land management practices on soil erodibility in two villages in the Plateau of Abomey. Soil samples were collected on plots under Sustainable Land Management (SLM) measures (direct seeding, maize residue management and soybean-cereal rotation) and on their adjacent control. The soil samples were prepared and analyzed in laboratory to determine variables such as soil permeability, organic matter content, and particle size. Soil erodibility was determined as proposed by Wischmeier & Smith. The effect of SLM practices was significant (0.02) on soil permeability. On plots under SLM measurements, soil permeability is higher with an average of 93.97 mm/h at Folly and 82.43 mm/h at Hanagbo. SLM measurements significantly (0.04) added organic matter to the soil. The average organic matter of the plots under SLM measures in Folly varies from 0.73% to 1.39% while it varies from 0.49% to 0.73% in the control plots. In Hanagbo, the average organic matter of the plots under SLM measures varies from 1.86% to 2.48% against 1.41% to 1.66% for the control plots. Regarding soil erodibility, it was found that the influence of SLM measures is significant in both villages. In villages, direct seeding and maize residue management significantly (0.008) reduced soil erodibility compared to their adjacent controls, while the soybean-cereal rotation measure increased soil erodibility compared to plot witnesses. The average soil erodibility of plots under SLM measures varies by 0.21 t⋅h/Mj⋅mm at 0.38 t⋅h/Mj⋅mm in the village of Hanagbo and 0.25 t⋅h/Mj⋅mm at 0.38 t⋅h/Mj⋅mm in the village of Folly. It varies from 0.24 t⋅h/Mj⋅mm at 0.28 t⋅h/Mj⋅mm for the control plots at Hanagbo and 0.31 t⋅h/Mj⋅mm at 0.37 t⋅h/Mj⋅mm in Folly. These practices can therefore be used for the sustainable use of agricultural land.
文摘Among the models used to assess water erosion,the RUSLE model is commonly used.Policy makers can act on cover(C-factor)and conservation practice(P-factor)to reduce erosion,with less costly action on soil surface characteristics.However,the widespread use of vegetation indices such as NDVI does not allow for a proper assessment of the C-factor in drylands where stones,crusted surfaces and litter strongly influence soil protection.Two sub-factors of C,canopy cover(CC)and soil cover(SC),can be assessed from phytoecological measurements that include gravel-pebbles cover,physical mulch,annual and perennial vegetation.This paper introduces a method to calculate the C-factor from phytoecological data and,in combination with remote sensing and a geographic information system(GIS),to map it over large areas.A supervised classification,based on field phytoecological data,is applied to radiometric data from Landsat-8/OLI satellite images.Then,a C-factor value,whose SC and CC subfactors are directly derived from the phytoecological measurements,is assigned to each land cover unit.This method and RUSLE are implemented on a pilot region of 3828 km^(2) of the Saharan Atlas,composed of rangelands and steppe formations,and intended to become an observatory.The protective effect against erosion by gravel-pebbles(50%)is more than twice that of vegetation(23%).The C-factor derived from NDVI(0.67)is higher and more evenly distributed than that combining these two contributions(0.37 on average).Finally,priorities are proposed to decision-makers by crossing the synthetic map of erosion sensitivity and a decision matrix of management priorities.
文摘Soil erosion prediction technology began over 70 years ago when Austin Zingg published a relationship between soil erosion(by water)and land slope and length,followed shortly by a relationship by Dwight Smith that expanded this equation to include conservation practices.But,it was nearly 20 years before this work's expansion resulted in the Universal Soil Loss Equation(USLE),perhaps the foremost achievement in soil erosion prediction in the last century.The USLE has increased in application and complexity,and its usefulness and limitations have led to the development of additional technologies and new science in soil erosion research and prediction.Main among these new technologies is the Water Erosion Prediction Project(WEPP)model,which has helped to overcome many of the shortcomings of the USLE,and increased the scale over which erosion by water can be predicted.Areas of application of erosion prediction include almost all land types:urban,rural,cropland,forests,rangeland,and construction sites.Specialty applications of WEPP include prediction of radioactive material movement with soils at a superfund cleanup site,and near real-time daily estimation of soil erosion for the entire state of Iowa.
基金financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nivel Superior-Brazil(CAPES)(Finance Code 001)supported by grant from the Con-selho Nacional de Desenvolvimento Científicoe Tecnològico(CNPq)financed in part by the Agênda da Bacia do Rio Paraíba do Sul(AGEVAP)Guandu Committee(Grant number 02/2016).
文摘The effect of different rainfall patterns on surface runoff,infiltration and thus soil losses and sediment concentrations are still in the focus of current research.In most simulated rainfall experiments,pre-cipitation is applied at a fixed intensity for a fixed time.However,the impact of rainfall patterns on soil erosion processes may be different varying the rainfall duration and intensity that produces an event with similar rainfall erosivity values.Twenty-five rainfall events were applied on micro-scale runoff plots in a soil covered with corn straw to evaluate the sediment yield and runoff rates.The different rainfall types were composed by association of duration(Dur)and intensity(IP)with the same erosivity value.The Dur varied from 38 to 106 min and the IP varied from 75.0 to 44.6 mm h^(-1).The sediment yield varied from 1.89±1.26 g m^(-2) to 4.02±2.66 g m^(-2) and runoff ranged from 16.9±8.74 mm to 32.63±10.67 mm with highest rates occurring with high intensity and low duration.The highest rainfall intensity provides the maximum sediment yield(0.138 g m^(-2) min^(-1))and runoff rates(0.87 mm min^(-1)).The time to start surface runoff varied from 14 to 19.2 min and it was longer in treatments with longer durations and low precipitation intensity.No difference was found in the amount of sediments applying rain with the same erosivity and different associations of duration and intensity.However,the intensity and duration of the rain,with the same erosivity,altered the amount and time of runoff.In rainfall experiments with con-stant intensity and fixed time,the erosion rates depend on the duration of the applied rain.Therefore,the results of this study can contribute to the development of new perspectives in the design of water erosion experiments with simulated rain considering the duration,intensity and also the association of these variables to produce rainfall that delivery the same soil erosion capacity.