The Loess Plateau is one typical area of serious soil erosion in the world. China has implemented ′Grain for Green′(GFG) project to restore the eco-environment of the Loess Plateau since 1999. With the GFG project s...The Loess Plateau is one typical area of serious soil erosion in the world. China has implemented ′Grain for Green′(GFG) project to restore the eco-environment of the Loess Plateau since 1999. With the GFG project subsidy approaching the end, it is concerned that farmers of fewer subsidies may reclaim land again. Thus, ′Gully Land Consolidation Project′(GLCP) was initiated in 2010. The core of the GLCP was to create more land suitable for farming in gullies so as to reduce land reclamation on the slopes which are ecological vulnerable areas. This paper aims to assess the effect of the GLCP on soil erosion problems by studying Wangjiagou project region located in the central part of Anzi valley in the middle of the Loess Plateau, mainly using the revised universal soil loss equation(RUSLE) based on GIS. The findings show that the GLCP can help to reduce soil shipment by 9.87% and it creates more terraces and river-nearby land suitable for farming which account for 27.41% of the whole study area. Thus, it is feasible to implement the GLCP in places below gradient 15°, though the GLCP also intensifies soil erosion in certain places such as field ridge, village land, floodplain, natural grassland, and shrub land. In short, the GLCP develops new generation dam land and balances the short-term and long-term interests to ease the conflicts between economic development and environmental protection. Furthermore, the GLCP and the GFG could also be combined preferably. On the one hand, the GFG improves the ecological environment, which could offer certain safety to the GLCP, on the other hand, the GLCP creates more farmland favorable for farming in gullies instead of land reclamation on the slopes, which could indirectly protect the GFG project.展开更多
To give soils and soil degradation,which are among the most crucial threats to ecosystem stability,social and political visibility,small and large scale modelling and mapping of soil erosion is inevitable.The most wid...To give soils and soil degradation,which are among the most crucial threats to ecosystem stability,social and political visibility,small and large scale modelling and mapping of soil erosion is inevitable.The most widely used approaches during an 80year history of erosion modelling are Universal Soil Loss Equation (USLE)-type based algorithms which have been applied in 109 countries.Addressing soil erosion by water (excluding gully erosion and land sliding),we start this review with a statistical evaluation of nearly 2,000 publications).We discuss model developments which use USLE-type equations as basis or side modules,but we also address recent development of the single USLE parameters (R,K,LS,C,P).Importance,aim and limitations of model validation as well as a comparison of USLE-type models with other erosion assessment tools are discussed.Model comparisons demonstrate that the application of process-based physical models (e.g.,WEPP or PESERA) does not necessarily result in lower uncertainties compared to more simple structured empirical models such as USLE-type algorithms.We identified four key areas for future research:(i) overcoming the principally different nature of modelled (gross) versus measured (net) erosion rates,in coupling on-site erosion risk to runoff patterns,and depositional regime,(ii) using the recent increase in spatial resolution of remote sensing data to develop process based models for large scale applications,(iii) strengthen and extend measurement and monitoring programs to build up validation data sets,and (iv) rigorous uncertainty assessment and the application of objective evaluation criteria to soil erosion modelling.展开更多
Soil erosion is a direct product of the complex interactions between natural and anthropogenic factors.Such factors vary over space and time,making the assessment of soil erosion even more difficult.Empirical erosion ...Soil erosion is a direct product of the complex interactions between natural and anthropogenic factors.Such factors vary over space and time,making the assessment of soil erosion even more difficult.Empirical erosion models such as the Revised Universal Soil Loss Equation (RUSLE) provides a rather simple and yet comprehensive framework for assessing soil erosion and its causative factors.RUSLE considers rainfall (R),topography (LS),soil erodibility (K),cover management (C),and support practice (P) as important factors affecting soil erosion.In the past few years,RUSLE has benefited tremendously from advances in geospatial technologies like Geographic Information System (GIS) and remote sensing.In this paper,an overview of recent developments on the use of these geospatial technologies in deriving individual RUSLE factors is provided,placing an emphasis on related successes and challenges.This review is expected to improve the understanding of the role played by such technologies in deriving RUSLE parameters despite existing challenges.Future research,however,must pay special attention to error assessment of remote sensing-derived RUSLE parameters.展开更多
An integrated remote sensing (RS) and geographic information system (GIS) technique was employed to characterize the spatial distribution of the risk of soil erosion by water on Latakia district, Syria. The universal ...An integrated remote sensing (RS) and geographic information system (GIS) technique was employed to characterize the spatial distribution of the risk of soil erosion by water on Latakia district, Syria. The universal soil loss equation (USLE) was used to calculate the annual soil loss rates for Latakia soils. Mainly, remote sensing data, soil survey, land use inventory, elevation data and climatic atlases are used as resource data sets to generate USLE factor values. The results revealed that integration of GIS/RS with USLE was a practical and effective approach for monitoring soil erosion over large areas.展开更多
Severe soil erosion in the middle and upper reaches of Yangtze River has been regarded as a major environmental problem. The on-site impact of soil erosion on agricultural production and the off-site impact on floods ...Severe soil erosion in the middle and upper reaches of Yangtze River has been regarded as a major environmental problem. The on-site impact of soil erosion on agricultural production and the off-site impact on floods and sedimentation in Yangtze Rive are well known. A quantitative assessment of soil erosion intensity is still scanty for developing appropriate soil erosion control measures for different land use types and zones in this region. This article constructs a localized USLE and estimates the average soil loss in the Jinsha River Region in Yunnan Province, one of the priority areas for soil erosion control in the middle and upper reaches of Yangtze River. The estimation is done under different land uses and zones in this basin. The estimation shows that while soil erosion in the cultivated land is the most severe, 36～40% of the garden and forest land suffers from soil erosion of various degrees due to lack of ground cover and other factors. Soil erosion in the pasture is modest when the ground cover is well maintained. It also confirmed that terracing can reduce soil erosion intensity significantly on the cultivated land. Research findings suggest that sufficient attention must be paid to regeneration of the ground cover in reforestation programs. In addition to mass reforestation efforts, restoration of grassland and terracing of the cultivated land should also play an important role in erosion control.展开更多
A new water soluble surfaCe film-forming material was developed and its effect on reducing ammonia volatilization from an alkaline solution was investigated in laborstory. Results showed that the new film formed by th...A new water soluble surfaCe film-forming material was developed and its effect on reducing ammonia volatilization from an alkaline solution was investigated in laborstory. Results showed that the new film formed by the material was not only more effective in reducing ammonia loss than any other films tested but also much cheaper. The optimum amount of addition of the new film-forming material was about 10times the theoretical amount to form a monomolecular film. Under the experimental conditions, the new film could effectively depress the ammonia volatilization for at least 6 days. The cumulative ammonia loss rates for different films were fitted to a simple logistic equation, and some important parameters such as the cumulative loss, and the maximum and average volatilization rates were calculated. The effect of different films could be, therefore, compared quantitatively, indicating the new film was most effective in depressing ammonia volatilization.展开更多
The Revised Universal Soil Loss Equation （RUSLE） was applied to assess the spatial distribution and dynamic properties of soil loss with geographic information system （GIS） and remote sensing （RS） technologies. ...The Revised Universal Soil Loss Equation （RUSLE） was applied to assess the spatial distribution and dynamic properties of soil loss with geographic information system （GIS） and remote sensing （RS） technologies. To improve the accuracy of soil-erosion estimates, a new C-factor estimation model was developed based on land cover and time series normalized difference vegetation index （NDVI） datasets. The new C-factor was then applied in the RUSLE to integrate rainfall, soil, vegetation, and topography data of different periods, and thus monitor the distribution of soil erosion patterns and their dynamics during a 3o-year period of the upstream watershed of Miynn Reservoir （UWMR）, China. The results showed that the new C-factor estimation method, which considers land cover status and dynamics, and explicitly incorporates within-land cover variability, was more rational, quantitative, and reliable. An average annual soil loss in UWMR of 25.68, 21.04, and 16.8o t ha-1 a-1 was estimated for 1990, 2000 and 2010, respectively, corroborated by comparing spatial and temporal variation in sediment yield. Between 2000 and 2010, a 1.38% average annual increase was observed in the area of lands that lost less than 5 t ha-1 a^-1, while during 1990-2000 such lands only increased on average by o.46%. Areas that classified as severe, very severe and extremely severe accounted for 5.68% of the total UWMR in 2010, and primarily occurred in dry areas or grasslands of sloping fields. The reason for the change in rate of soil loss is explained by an increased appreciation of soil conservation by developers and planners. Moreover,we recommend that UWMR watershed adopt further conservation measures such as terraced plowing of dry land, afforestation, or grassland enclosures as part of a concerted effort to reduce on-going soil erosion.展开更多
Many kinds of uncertainties are involved, such as random, fuzzy, grey, unascertained property and so on, in soil erosion process. To exactly predict the non-point source pollution loads, some uncertainties should be t...Many kinds of uncertainties are involved, such as random, fuzzy, grey, unascertained property and so on, in soil erosion process. To exactly predict the non-point source pollution loads, some uncertainties should be taken into consideration. Aiming at the deficiency of present blind number theory being helpless for fuzziness, a novel blind number, i.e. extended-blind number, was introduced by substituting a set of triangular fuzzy numbers （TFNs）, expressed as a-cuts, for interval values in present blind number, and the expected value of extended-blind number was also brought forward by referring to the current blind number theory. On the basis of denoting the parameters of Uni- versal Soil Loss Equation （USLE） as extended-blind parameters, a novel USLE model was established for quantitatively evaluating soil erosion loss and non-point source pollution loads. As a case, the uncertain USLE was employed for predicting the soil erosion loss and non-point source pollution loads of absorbed nitrogen and phosphorus in a dis- trict in the Hangbu-Fengle River basin, in the upstream of Chaohu Lake watershed. The results show that it is feasible in theory to extend blind number into fuzzy environment and reliable on conclusion to apply extended-blind number theory for predicting non-point source pollution loads.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41130748,41471143)
文摘The Loess Plateau is one typical area of serious soil erosion in the world. China has implemented ′Grain for Green′(GFG) project to restore the eco-environment of the Loess Plateau since 1999. With the GFG project subsidy approaching the end, it is concerned that farmers of fewer subsidies may reclaim land again. Thus, ′Gully Land Consolidation Project′(GLCP) was initiated in 2010. The core of the GLCP was to create more land suitable for farming in gullies so as to reduce land reclamation on the slopes which are ecological vulnerable areas. This paper aims to assess the effect of the GLCP on soil erosion problems by studying Wangjiagou project region located in the central part of Anzi valley in the middle of the Loess Plateau, mainly using the revised universal soil loss equation(RUSLE) based on GIS. The findings show that the GLCP can help to reduce soil shipment by 9.87% and it creates more terraces and river-nearby land suitable for farming which account for 27.41% of the whole study area. Thus, it is feasible to implement the GLCP in places below gradient 15°, though the GLCP also intensifies soil erosion in certain places such as field ridge, village land, floodplain, natural grassland, and shrub land. In short, the GLCP develops new generation dam land and balances the short-term and long-term interests to ease the conflicts between economic development and environmental protection. Furthermore, the GLCP and the GFG could also be combined preferably. On the one hand, the GFG improves the ecological environment, which could offer certain safety to the GLCP, on the other hand, the GLCP creates more farmland favorable for farming in gullies instead of land reclamation on the slopes, which could indirectly protect the GFG project.
文摘To give soils and soil degradation,which are among the most crucial threats to ecosystem stability,social and political visibility,small and large scale modelling and mapping of soil erosion is inevitable.The most widely used approaches during an 80year history of erosion modelling are Universal Soil Loss Equation (USLE)-type based algorithms which have been applied in 109 countries.Addressing soil erosion by water (excluding gully erosion and land sliding),we start this review with a statistical evaluation of nearly 2,000 publications).We discuss model developments which use USLE-type equations as basis or side modules,but we also address recent development of the single USLE parameters (R,K,LS,C,P).Importance,aim and limitations of model validation as well as a comparison of USLE-type models with other erosion assessment tools are discussed.Model comparisons demonstrate that the application of process-based physical models (e.g.,WEPP or PESERA) does not necessarily result in lower uncertainties compared to more simple structured empirical models such as USLE-type algorithms.We identified four key areas for future research:(i) overcoming the principally different nature of modelled (gross) versus measured (net) erosion rates,in coupling on-site erosion risk to runoff patterns,and depositional regime,(ii) using the recent increase in spatial resolution of remote sensing data to develop process based models for large scale applications,(iii) strengthen and extend measurement and monitoring programs to build up validation data sets,and (iv) rigorous uncertainty assessment and the application of objective evaluation criteria to soil erosion modelling.
文摘Soil erosion is a direct product of the complex interactions between natural and anthropogenic factors.Such factors vary over space and time,making the assessment of soil erosion even more difficult.Empirical erosion models such as the Revised Universal Soil Loss Equation (RUSLE) provides a rather simple and yet comprehensive framework for assessing soil erosion and its causative factors.RUSLE considers rainfall (R),topography (LS),soil erodibility (K),cover management (C),and support practice (P) as important factors affecting soil erosion.In the past few years,RUSLE has benefited tremendously from advances in geospatial technologies like Geographic Information System (GIS) and remote sensing.In this paper,an overview of recent developments on the use of these geospatial technologies in deriving individual RUSLE factors is provided,placing an emphasis on related successes and challenges.This review is expected to improve the understanding of the role played by such technologies in deriving RUSLE parameters despite existing challenges.Future research,however,must pay special attention to error assessment of remote sensing-derived RUSLE parameters.
基金Project supported by the National Natural Science Foundation of China (No.40001008) and GermanFederal Ministry for Research an
文摘An integrated remote sensing (RS) and geographic information system (GIS) technique was employed to characterize the spatial distribution of the risk of soil erosion by water on Latakia district, Syria. The universal soil loss equation (USLE) was used to calculate the annual soil loss rates for Latakia soils. Mainly, remote sensing data, soil survey, land use inventory, elevation data and climatic atlases are used as resource data sets to generate USLE factor values. The results revealed that integration of GIS/RS with USLE was a practical and effective approach for monitoring soil erosion over large areas.
基金the result of project(No.40061006)funded by the National Natural Sciences Foundation of China
文摘Severe soil erosion in the middle and upper reaches of Yangtze River has been regarded as a major environmental problem. The on-site impact of soil erosion on agricultural production and the off-site impact on floods and sedimentation in Yangtze Rive are well known. A quantitative assessment of soil erosion intensity is still scanty for developing appropriate soil erosion control measures for different land use types and zones in this region. This article constructs a localized USLE and estimates the average soil loss in the Jinsha River Region in Yunnan Province, one of the priority areas for soil erosion control in the middle and upper reaches of Yangtze River. The estimation is done under different land uses and zones in this basin. The estimation shows that while soil erosion in the cultivated land is the most severe, 36～40% of the garden and forest land suffers from soil erosion of various degrees due to lack of ground cover and other factors. Soil erosion in the pasture is modest when the ground cover is well maintained. It also confirmed that terracing can reduce soil erosion intensity significantly on the cultivated land. Research findings suggest that sufficient attention must be paid to regeneration of the ground cover in reforestation programs. In addition to mass reforestation efforts, restoration of grassland and terracing of the cultivated land should also play an important role in erosion control.
文摘A new water soluble surfaCe film-forming material was developed and its effect on reducing ammonia volatilization from an alkaline solution was investigated in laborstory. Results showed that the new film formed by the material was not only more effective in reducing ammonia loss than any other films tested but also much cheaper. The optimum amount of addition of the new film-forming material was about 10times the theoretical amount to form a monomolecular film. Under the experimental conditions, the new film could effectively depress the ammonia volatilization for at least 6 days. The cumulative ammonia loss rates for different films were fitted to a simple logistic equation, and some important parameters such as the cumulative loss, and the maximum and average volatilization rates were calculated. The effect of different films could be, therefore, compared quantitatively, indicating the new film was most effective in depressing ammonia volatilization.
基金supported by the National Natural Science Foundation of China (Grant No.41101399)the open fund of State Key Laboratory of Remote Sensing ScienceJointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University,China
文摘The Revised Universal Soil Loss Equation （RUSLE） was applied to assess the spatial distribution and dynamic properties of soil loss with geographic information system （GIS） and remote sensing （RS） technologies. To improve the accuracy of soil-erosion estimates, a new C-factor estimation model was developed based on land cover and time series normalized difference vegetation index （NDVI） datasets. The new C-factor was then applied in the RUSLE to integrate rainfall, soil, vegetation, and topography data of different periods, and thus monitor the distribution of soil erosion patterns and their dynamics during a 3o-year period of the upstream watershed of Miynn Reservoir （UWMR）, China. The results showed that the new C-factor estimation method, which considers land cover status and dynamics, and explicitly incorporates within-land cover variability, was more rational, quantitative, and reliable. An average annual soil loss in UWMR of 25.68, 21.04, and 16.8o t ha-1 a-1 was estimated for 1990, 2000 and 2010, respectively, corroborated by comparing spatial and temporal variation in sediment yield. Between 2000 and 2010, a 1.38% average annual increase was observed in the area of lands that lost less than 5 t ha-1 a^-1, while during 1990-2000 such lands only increased on average by o.46%. Areas that classified as severe, very severe and extremely severe accounted for 5.68% of the total UWMR in 2010, and primarily occurred in dry areas or grasslands of sloping fields. The reason for the change in rate of soil loss is explained by an increased appreciation of soil conservation by developers and planners. Moreover,we recommend that UWMR watershed adopt further conservation measures such as terraced plowing of dry land, afforestation, or grassland enclosures as part of a concerted effort to reduce on-going soil erosion.
基金Under the auspices of Tackling Key Program for Science and Technology of Anhui Province (No. 07010302165)Natural Science Foundation of Anhui Province (No. 050450303)
文摘Many kinds of uncertainties are involved, such as random, fuzzy, grey, unascertained property and so on, in soil erosion process. To exactly predict the non-point source pollution loads, some uncertainties should be taken into consideration. Aiming at the deficiency of present blind number theory being helpless for fuzziness, a novel blind number, i.e. extended-blind number, was introduced by substituting a set of triangular fuzzy numbers （TFNs）, expressed as a-cuts, for interval values in present blind number, and the expected value of extended-blind number was also brought forward by referring to the current blind number theory. On the basis of denoting the parameters of Uni- versal Soil Loss Equation （USLE） as extended-blind parameters, a novel USLE model was established for quantitatively evaluating soil erosion loss and non-point source pollution loads. As a case, the uncertain USLE was employed for predicting the soil erosion loss and non-point source pollution loads of absorbed nitrogen and phosphorus in a dis- trict in the Hangbu-Fengle River basin, in the upstream of Chaohu Lake watershed. The results show that it is feasible in theory to extend blind number into fuzzy environment and reliable on conclusion to apply extended-blind number theory for predicting non-point source pollution loads.
