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
Wind and water erosion are among the most important causes of soil loss, and understanding their interactions is important for estimating soil quality and environmental impacts in regions where both types of erosion o...Wind and water erosion are among the most important causes of soil loss, and understanding their interactions is important for estimating soil quality and environmental impacts in regions where both types of erosion occur. We used a wind tunnel and simulated rainfall to study sediment yield, particle-size distribution and the fractal dimension of the sediment particles under wind and water erosion. The experiment was conducted with wind ero- sion firstly and water erosion thereafter, under three wind speeds (0, 11 and 14 m/s) and three rainfall intensities (60, 80 and 100 ram/h). The results showed that the sediment yield was positively correlated with wind speed and rain- fall intensity (P〈0.01). Wind erosion exacerbated water erosion and increased sediment yield by 7.25%-38.97% relative to the absence of wind erosion. Wind erosion changed the sediment particle distribution by influencing the micro-topography of the sloping land surface. The clay, silt and sand contents of eroded sediment were also posi- tively correlated with wind speed and rainfall intensity (P〈0.01). Wind erosion increased clay and silt contents by 0.35%-19.60% and 5.80%-21.10%, respectively, and decreased sand content by 2.40%-8.33%, relative to the absence of wind erosion. The effect of wind erosion on sediment particles became weaker with increasing rainfall intensities, which was consistent with the variation in sediment yield. However, particle-size distribution was not closely correlated with sediment yield (P〉0.05). The fractal dimension of the sediment particles was significantly different under different intensities of water erosion (P〈0.05), but no significant difference was found under wind and water erosion. The findings reported in this study implicated that both water and wind erosion should be controlled to reduce their intensifying effects, and the controlling of wind erosion could significantly reduce water erosion in this wind-water erosion crisscross region.展开更多
Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evalua...Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evaluation and hazard control in the real world. Analyzing the related scale issues is thus urgent for a better understanding of erosion variations as well as reducing such erosion. In this review article, water erosion dynamics across three spatial scales including plot, watershed, and regional scales were selected and discussed. For the study purposes and objectives, the advantages and disadvantages of these scales all demonstrate clear spatial-scale dependence. Plot scale studies are primarily focused on abundant data collection and mechanism discrimination of erosion generation, while watershed scale studies provide valuable information for watershed management and hazard control as well as the development of quantitatively distributed models. Regional studies concentrate more on large-scale erosion assessment, and serve policymakers and stakeholders in achieving the basis for regulatory policy for comprehensive land uses. The results of this study show that the driving forces and mechanisms of water erosion variations among the scales are quite different. As a result, several major aspects contributing to variations in water erosion across the scales are stressed: differences in the methodologies across various scales, different sink-source roles on water erosion processes, and diverse climatic zones and morphological regions. This variability becomes more complex in the context of accelerated global change. The changing climatic factors and earth surface features are considered the fourth key reason responsible for the increased variability of water erosion across spatial scales.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
In semi-arid regions, complex erosion resulted from a combination of wind and water actions has led to a massive soil loss and a comprehensive understanding of its mechanism is the first step toward prevention of the ...In semi-arid regions, complex erosion resulted from a combination of wind and water actions has led to a massive soil loss and a comprehensive understanding of its mechanism is the first step toward prevention of the erosion. However, the mutual influences between wind erosion and water erosion have not been fully understood. This research used a wind tunnel and two rainfall simulators and simulated two rounds of alternations between wind erosion and water erosion(i.e., 1^(st) wind erosion–1^(st) water erosion and 2^(nd) wind erosion–2^(nd) water erosion) on three slopes(5°, 10°, and 15°) with six wind speeds(0, 9, 11, 13, 15, and 20 m/s) and five rainfall intensities(0, 30, 45, 60, and 75 mm/h). The objective was to analyze the influences of wind erosion on succeeding water erosion. Results showed that the effects of wind erosion on water erosion were not the same in the two rounds of tests. In the 1^(st) round of tests, wind erosion first restrained and then intensified water erosion mostly because the blocking effect of wind-sculpted micro-topography on surface flow was weakened with the increase in slope. In the 2^(nd) round of tests, wind erosion intensified water erosion on beds with no rills at gentle slopes and low rainfall intensities or with large-size rills at steep slopes and high rainfall intensities. Wind erosion restrained water erosion on beds with small rills at moderate slopes and moderate rainfall intensities. The effects were mainly related to the fine grain layer, rills and slope of the original bed in the 2^(nd) round of tests. The findings can deepen our understanding of complex erosion resulted from a combination of wind and water actions and provide scientific references to regional soil and water conservation.展开更多
Using water erosion data from three national soil erosion remote-sensing surveys (the first:1985-1986; the second:1995-1996; the third: 2000-2001) and carbon density data from the second national soil survey (19...Using water erosion data from three national soil erosion remote-sensing surveys (the first:1985-1986; the second:1995-1996; the third: 2000-2001) and carbon density data from the second national soil survey (1979-1992), we computed soil carbon removal caused by water erosion, and analyzed its spatial distribution and temporal dynamics in China. Results revealed that the total removal of soil carbon caused by water erosion was about 74.61 Tg C y^-1 , of which 51.49 Tg C y^-1 was organic carbon, and 23.12 Tg C y^-1 was inorganic carbon. The main erosion level of the whole is moderate erosion. Among the seven erosion regions, the Southwest Karst Region had the most significant removal of soil organic carbon, which was 26.48% of the total and mainly due to its moderate erosion. In contrast, about 67.62% of the soil inorganic carbon removal occurred in the Loess Plateau Region, which mainly due to its highly intense and intense erosion. As a whole, the removals of soil carbon caused by water erosion represented a decreasing trend among the three national soil erosion remote-sensing surveys. Between the first and the second survey, soil carbon removal decreased by 11.66 Tg C y^-1 , of which 81.93% was organic carbon. Compared with that in the second survey, soil carbon removal decreased by 1.65 Tg C y^-1 in the third survey, of which 1.514 Tg C y^-1 was organic carbon, and 0.134 Tg C y^-1 was inorganic carbon.展开更多
The C factor in Universal Soil loss Equation reflecting the effect of vegetation on soil erosion by water is one of the important parameters for estimating soil erosion rate and selecting appropriate land use patterns...The C factor in Universal Soil loss Equation reflecting the effect of vegetation on soil erosion by water is one of the important parameters for estimating soil erosion rate and selecting appropriate land use patterns. In this study, the C factor for nine types of grassland and woodland was estimated from 195 plot-year observation data of six groups of soil erosion experiments on Loess Plateau. The result indicates that the effects of woodland and grassland on soil erosion keep approximately uniform after two or three years' growth. The estimated woodland C factor ranges from 0.004 to 0.164, and the grassland C factor ranges from 0.071 to 0.377, showing that the effect of woodland and grassland on soil conservation is greatly better than that of cropland. The study results can be used to compare or estimate the soil loss from land with different vegetation cover, and are the useful references for land use pattern selection and the project of returning cropland to forest or grassland.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
Loess water erosion constitutes a great threat to the safety of the West-to-East Gas Pipeline in China. Through aerial-photo interpretation and investigation of the typical region (Zichang (子长)-Yongping (水坪) ...Loess water erosion constitutes a great threat to the safety of the West-to-East Gas Pipeline in China. Through aerial-photo interpretation and investigation of the typical region (Zichang (子长)-Yongping (水坪) Section) where the loess water erosion problem is intensely developed, the influence of water erosion on the pipeline in the loess area can be manifested as the following 3 aspects: (1) surface and gully erosion causes the base overhead and pipeline exposure; (2) underground erosion forms caves, which may cause surface subsidence and foundation failure; (3) water erosion of loess may destroy the balance of slopes and cause geological hazards like landslide, collapse and debris flow. Presently, the controlling methods are mainly concrete or grouted rubble protection. These methods are not only high in cost but also have poor effect and poor durability. This article suggests a method of controlling the loess water erosion problem with soil solidified material. Then, related tests are conducted. The results of uniaxial compression, permeability, and anti-erosion ability tests indicate that the mechanical properties and anti-erosion ability of solidified loess were improved significantly.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 objective of this study is to develop a unique modeling approach for fast assessment of massive soil erosion by water at a regional scale in the Loess Plateau, China. This approach relies on an understanding of bo...The objective of this study is to develop a unique modeling approach for fast assessment of massive soil erosion by water at a regional scale in the Loess Plateau, China. This approach relies on an understanding of both regional patterns of soil loss and its impact factors in the plateau area. Based on the regional characteristics of precipitation, vegetation and land form, and with the use of Landsat TM and ground investigation data, the entire Loess Plateau was first divided into 3 380 Fundamental Assessment Units (FAUs) to adapt to this regional modeling and fast assessment. A set of easily available parameters reflecting relevant water erosion factors at a regional scale was then developed, in which dynamic and static factors were discriminated. Arclnfo GIS was used to integrate all essential data into a central database. A resulting mathematical model was established to link the sediment yields and the selected variables on the basis of FAUs through overlay in GIS and multiple regression analyses. The sensitivity analyses and validation results show that this approach works effectively in assessing large area soil erosion, and also helps to understand the regional associations of erosion and its impact factors, and thus might significantly contribute to planning and policymaking for a large area erosion control in the Loess Plateau.展开更多
Complex erosion by wind and water, which is also called aeolian-fluvial interactions, is an important erosion process and landscape in arid and semiarid regions. The effectiveness of links between wind and water proce...Complex erosion by wind and water, which is also called aeolian-fluvial interactions, is an important erosion process and landscape in arid and semiarid regions. The effectiveness of links between wind and water process, spatial environmental transitions and temporal environmental change are the three main driving forces determining the geomorphologic significance of aeolian-fluvial interactions. As a complex interrelating and intercoupling system, complex erosion by wind and water has spatial- temporal variation features. The process of complex erosion by wind and water can be divided into palaeoenvironmental process and contemporary process. Early work in drylands has often been attributed to one of two schools advocating either an 'aeolianist' or a 'fluvialist' perspective, so it was not until the 1930s that the research on complex erosion by wind and water had been conducted. There are two obstacles restricting the research of complex erosion by wind and water. Firstly, how to transform in different temporal and spatial scales is still unsettled; and secondly, the research methodology is still immature. In the future, the mechanism and control of erosion, the complex soil erodibility in wind and water erosion will be the focus of research on complex erosion by wind and water.展开更多
As an important parameter in the soil erosion model, soil surface roughness(SSR) is used to quantitatively describe the micro-relief on agricultural land. SSR has been extensively studied both experimentally and the...As an important parameter in the soil erosion model, soil surface roughness(SSR) is used to quantitatively describe the micro-relief on agricultural land. SSR has been extensively studied both experimentally and theoretically; however, no studies have focused on understanding SSR on the Loess Plateau of China. This study investigated changes in SSR for three different tillage practices on the Loess Plateau of China and the effects of SSR on runoff and erosion yield during simulated rainfall. The tillage practices used were zero tillage(ZT), shallow hoeing(SH) and contour ploughing(CP). Two rainfall intensities were applied, and three stages of water erosion processes(splash erosion(I), sheet erosion(II) and rill erosion(III)) were analyzed for each rainfall intensity. The chain method was used to measure changes in SSR both initially and after each stage of rainfall. A splash board was used to measure the splash erosion at stage I. Runoff and sediment data were collected continuously at 2-min intervals during rainfall erosion stages II and III. We found that SSR of the tilled surfaces ranged from 1.0% to 21.9% under the three tillage practices, and the order of the initial SSR for the three treatments was ZT〈SH〈CP. For the ZT treatment, SSR increased slightly from stage I to III, whereas for the SH and CP treatments, SSR decreased by 44.5% and 61.5% after the three water erosion stages, respectively, and the greatest reduction in SSR occurred in stage I. Regression analysis showed that the changes in SSR with increasing cumulative rainfall could be described by a power function(R2〉0.49) for the ZT, SH and CP treatments. The runoff initiation time was longer in the SH and CP treatments than in the ZT treatment. There were no significant differences in the total runoff yields among the ZT, SH and CP treatments. Sediment loss was significantly smaller(P〈0.05) in the SH and CP treatments than in the ZT treatment.展开更多
In this paper,areas and main factors of wind erosion in black earth region of Northeast China were systematically analyzed,as well as the development trend of wind erosion in black earth region of Northeast China.In a...In this paper,areas and main factors of wind erosion in black earth region of Northeast China were systematically analyzed,as well as the development trend of wind erosion in black earth region of Northeast China.In addition,development trend of wind erosion in black earth region of Northeast China was analyzed from the aspects of the geographic position,climatic change law in recent 40 years and effects of northeast sand land desertification on wind erosion in black earth region,which had provided references for the research and prevention of wind erosion in soil of black earth region of Northeast China.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financially supported by the Special Program for Basic Research of the Ministry of Science and Technology, China (2014FY210100)the National Natural Science Foundation of China (41171422, 41271298)the West Light Foundation of the Chinese Academy of Sciences
文摘Wind and water erosion are among the most important causes of soil loss, and understanding their interactions is important for estimating soil quality and environmental impacts in regions where both types of erosion occur. We used a wind tunnel and simulated rainfall to study sediment yield, particle-size distribution and the fractal dimension of the sediment particles under wind and water erosion. The experiment was conducted with wind ero- sion firstly and water erosion thereafter, under three wind speeds (0, 11 and 14 m/s) and three rainfall intensities (60, 80 and 100 ram/h). The results showed that the sediment yield was positively correlated with wind speed and rain- fall intensity (P〈0.01). Wind erosion exacerbated water erosion and increased sediment yield by 7.25%-38.97% relative to the absence of wind erosion. Wind erosion changed the sediment particle distribution by influencing the micro-topography of the sloping land surface. The clay, silt and sand contents of eroded sediment were also posi- tively correlated with wind speed and rainfall intensity (P〈0.01). Wind erosion increased clay and silt contents by 0.35%-19.60% and 5.80%-21.10%, respectively, and decreased sand content by 2.40%-8.33%, relative to the absence of wind erosion. The effect of wind erosion on sediment particles became weaker with increasing rainfall intensities, which was consistent with the variation in sediment yield. However, particle-size distribution was not closely correlated with sediment yield (P〉0.05). The fractal dimension of the sediment particles was significantly different under different intensities of water erosion (P〈0.05), but no significant difference was found under wind and water erosion. The findings reported in this study implicated that both water and wind erosion should be controlled to reduce their intensifying effects, and the controlling of wind erosion could significantly reduce water erosion in this wind-water erosion crisscross region.
基金Under the auspices of National Natural Science Foundation of China (No. 40925003, 40930528, 40801041)
文摘Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evaluation and hazard control in the real world. Analyzing the related scale issues is thus urgent for a better understanding of erosion variations as well as reducing such erosion. In this review article, water erosion dynamics across three spatial scales including plot, watershed, and regional scales were selected and discussed. For the study purposes and objectives, the advantages and disadvantages of these scales all demonstrate clear spatial-scale dependence. Plot scale studies are primarily focused on abundant data collection and mechanism discrimination of erosion generation, while watershed scale studies provide valuable information for watershed management and hazard control as well as the development of quantitatively distributed models. Regional studies concentrate more on large-scale erosion assessment, and serve policymakers and stakeholders in achieving the basis for regulatory policy for comprehensive land uses. The results of this study show that the driving forces and mechanisms of water erosion variations among the scales are quite different. As a result, several major aspects contributing to variations in water erosion across the scales are stressed: differences in the methodologies across various scales, different sink-source roles on water erosion processes, and diverse climatic zones and morphological regions. This variability becomes more complex in the context of accelerated global change. The changing climatic factors and earth surface features are considered the fourth key reason responsible for the increased variability of water erosion across spatial scales.
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 Natural Science Foundation of China(41271286)the Innovative Research Group Project of the National Natural Science Foundation of China(413221001)
文摘In semi-arid regions, complex erosion resulted from a combination of wind and water actions has led to a massive soil loss and a comprehensive understanding of its mechanism is the first step toward prevention of the erosion. However, the mutual influences between wind erosion and water erosion have not been fully understood. This research used a wind tunnel and two rainfall simulators and simulated two rounds of alternations between wind erosion and water erosion(i.e., 1^(st) wind erosion–1^(st) water erosion and 2^(nd) wind erosion–2^(nd) water erosion) on three slopes(5°, 10°, and 15°) with six wind speeds(0, 9, 11, 13, 15, and 20 m/s) and five rainfall intensities(0, 30, 45, 60, and 75 mm/h). The objective was to analyze the influences of wind erosion on succeeding water erosion. Results showed that the effects of wind erosion on water erosion were not the same in the two rounds of tests. In the 1^(st) round of tests, wind erosion first restrained and then intensified water erosion mostly because the blocking effect of wind-sculpted micro-topography on surface flow was weakened with the increase in slope. In the 2^(nd) round of tests, wind erosion intensified water erosion on beds with no rills at gentle slopes and low rainfall intensities or with large-size rills at steep slopes and high rainfall intensities. Wind erosion restrained water erosion on beds with small rills at moderate slopes and moderate rainfall intensities. The effects were mainly related to the fine grain layer, rills and slope of the original bed in the 2^(nd) round of tests. The findings can deepen our understanding of complex erosion resulted from a combination of wind and water actions and provide scientific references to regional soil and water conservation.
基金supported by the National Key Basic Research and Development Program(2010CB833500)the"Strategic Priority Research Program-Climate Change:Carbon Budget and Relevant Issues"of the Chinese Academy of Sciences(XDA05050601)the National Natural Science Foundation of China(31070435,41071166)
文摘Using water erosion data from three national soil erosion remote-sensing surveys (the first:1985-1986; the second:1995-1996; the third: 2000-2001) and carbon density data from the second national soil survey (1979-1992), we computed soil carbon removal caused by water erosion, and analyzed its spatial distribution and temporal dynamics in China. Results revealed that the total removal of soil carbon caused by water erosion was about 74.61 Tg C y^-1 , of which 51.49 Tg C y^-1 was organic carbon, and 23.12 Tg C y^-1 was inorganic carbon. The main erosion level of the whole is moderate erosion. Among the seven erosion regions, the Southwest Karst Region had the most significant removal of soil organic carbon, which was 26.48% of the total and mainly due to its moderate erosion. In contrast, about 67.62% of the soil inorganic carbon removal occurred in the Loess Plateau Region, which mainly due to its highly intense and intense erosion. As a whole, the removals of soil carbon caused by water erosion represented a decreasing trend among the three national soil erosion remote-sensing surveys. Between the first and the second survey, soil carbon removal decreased by 11.66 Tg C y^-1 , of which 81.93% was organic carbon. Compared with that in the second survey, soil carbon removal decreased by 1.65 Tg C y^-1 in the third survey, of which 1.514 Tg C y^-1 was organic carbon, and 0.134 Tg C y^-1 was inorganic carbon.
文摘The C factor in Universal Soil loss Equation reflecting the effect of vegetation on soil erosion by water is one of the important parameters for estimating soil erosion rate and selecting appropriate land use patterns. In this study, the C factor for nine types of grassland and woodland was estimated from 195 plot-year observation data of six groups of soil erosion experiments on Loess Plateau. The result indicates that the effects of woodland and grassland on soil erosion keep approximately uniform after two or three years' growth. The estimated woodland C factor ranges from 0.004 to 0.164, and the grassland C factor ranges from 0.071 to 0.377, showing that the effect of woodland and grassland on soil conservation is greatly better than that of cropland. The study results can be used to compare or estimate the soil loss from land with different vegetation cover, and are the useful references for land use pattern selection and the project of returning cropland to forest or grassland.
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 the National Natural Science Foundation of China (No. 40972185)
文摘Loess water erosion constitutes a great threat to the safety of the West-to-East Gas Pipeline in China. Through aerial-photo interpretation and investigation of the typical region (Zichang (子长)-Yongping (水坪) Section) where the loess water erosion problem is intensely developed, the influence of water erosion on the pipeline in the loess area can be manifested as the following 3 aspects: (1) surface and gully erosion causes the base overhead and pipeline exposure; (2) underground erosion forms caves, which may cause surface subsidence and foundation failure; (3) water erosion of loess may destroy the balance of slopes and cause geological hazards like landslide, collapse and debris flow. Presently, the controlling methods are mainly concrete or grouted rubble protection. These methods are not only high in cost but also have poor effect and poor durability. This article suggests a method of controlling the loess water erosion problem with soil solidified material. Then, related tests are conducted. The results of uniaxial compression, permeability, and anti-erosion ability tests indicate that the mechanical properties and anti-erosion ability of solidified loess were improved significantly.
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.
基金Under the auspices of Northeast Normal University Sci-tech Innovation Incubation Program(No.NENU-STC08017)European Commission FP7 Project―PRACTICE(No.ENVI-2008-226818)
文摘The objective of this study is to develop a unique modeling approach for fast assessment of massive soil erosion by water at a regional scale in the Loess Plateau, China. This approach relies on an understanding of both regional patterns of soil loss and its impact factors in the plateau area. Based on the regional characteristics of precipitation, vegetation and land form, and with the use of Landsat TM and ground investigation data, the entire Loess Plateau was first divided into 3 380 Fundamental Assessment Units (FAUs) to adapt to this regional modeling and fast assessment. A set of easily available parameters reflecting relevant water erosion factors at a regional scale was then developed, in which dynamic and static factors were discriminated. Arclnfo GIS was used to integrate all essential data into a central database. A resulting mathematical model was established to link the sediment yields and the selected variables on the basis of FAUs through overlay in GIS and multiple regression analyses. The sensitivity analyses and validation results show that this approach works effectively in assessing large area soil erosion, and also helps to understand the regional associations of erosion and its impact factors, and thus might significantly contribute to planning and policymaking for a large area erosion control in the Loess Plateau.
基金National Natural Science Foundation of China, No.30371191 The Ministry of Education of China, No.272008 Program for New Century Excellent Talents in University
文摘Complex erosion by wind and water, which is also called aeolian-fluvial interactions, is an important erosion process and landscape in arid and semiarid regions. The effectiveness of links between wind and water process, spatial environmental transitions and temporal environmental change are the three main driving forces determining the geomorphologic significance of aeolian-fluvial interactions. As a complex interrelating and intercoupling system, complex erosion by wind and water has spatial- temporal variation features. The process of complex erosion by wind and water can be divided into palaeoenvironmental process and contemporary process. Early work in drylands has often been attributed to one of two schools advocating either an 'aeolianist' or a 'fluvialist' perspective, so it was not until the 1930s that the research on complex erosion by wind and water had been conducted. There are two obstacles restricting the research of complex erosion by wind and water. Firstly, how to transform in different temporal and spatial scales is still unsettled; and secondly, the research methodology is still immature. In the future, the mechanism and control of erosion, the complex soil erodibility in wind and water erosion will be the focus of research on complex erosion by wind and water.
基金supported by the National Natural Science Foundation of China (41271288, 41371273)
文摘As an important parameter in the soil erosion model, soil surface roughness(SSR) is used to quantitatively describe the micro-relief on agricultural land. SSR has been extensively studied both experimentally and theoretically; however, no studies have focused on understanding SSR on the Loess Plateau of China. This study investigated changes in SSR for three different tillage practices on the Loess Plateau of China and the effects of SSR on runoff and erosion yield during simulated rainfall. The tillage practices used were zero tillage(ZT), shallow hoeing(SH) and contour ploughing(CP). Two rainfall intensities were applied, and three stages of water erosion processes(splash erosion(I), sheet erosion(II) and rill erosion(III)) were analyzed for each rainfall intensity. The chain method was used to measure changes in SSR both initially and after each stage of rainfall. A splash board was used to measure the splash erosion at stage I. Runoff and sediment data were collected continuously at 2-min intervals during rainfall erosion stages II and III. We found that SSR of the tilled surfaces ranged from 1.0% to 21.9% under the three tillage practices, and the order of the initial SSR for the three treatments was ZT〈SH〈CP. For the ZT treatment, SSR increased slightly from stage I to III, whereas for the SH and CP treatments, SSR decreased by 44.5% and 61.5% after the three water erosion stages, respectively, and the greatest reduction in SSR occurred in stage I. Regression analysis showed that the changes in SSR with increasing cumulative rainfall could be described by a power function(R2〉0.49) for the ZT, SH and CP treatments. The runoff initiation time was longer in the SH and CP treatments than in the ZT treatment. There were no significant differences in the total runoff yields among the ZT, SH and CP treatments. Sediment loss was significantly smaller(P〈0.05) in the SH and CP treatments than in the ZT treatment.
基金Supported by National Natural Science Foundation of China(40901136)~~
文摘In this paper,areas and main factors of wind erosion in black earth region of Northeast China were systematically analyzed,as well as the development trend of wind erosion in black earth region of Northeast China.In addition,development trend of wind erosion in black earth region of Northeast China was analyzed from the aspects of the geographic position,climatic change law in recent 40 years and effects of northeast sand land desertification on wind erosion in black earth region,which had provided references for the research and prevention of wind erosion in soil of black earth region of Northeast China.