Current watershed-scale,nonpoint source pollution models do not represent the processes and impacts of agricultural best management practices on water quality with sufficient detail.A Water Erosion Pre-diction Project...Current watershed-scale,nonpoint source pollution models do not represent the processes and impacts of agricultural best management practices on water quality with sufficient detail.A Water Erosion Pre-diction Project-Water Quality(WEPP-WQ)model was recently developed which is capable of simulating nonpoint source pollutant transport in nonuniform hillslope conditions such as those with BMPs.However,WEPP-WQ has not been validated for these conditions,and prior validation work only eval-uated calibrated performance rather than uncalibrated performance,with the latter being most relevant to model applications.This study evaluated uncalibrated and calibrated model performance in two plot-scale,artificial rainfall studies.179 observations were compared to corresponding WEPP-WQ simulations of runoff,sediment yield,and soluble and particulate nutrient forms for both nitrogen and phosphorus.Uncalibrated validation results were mixed for the different field conditions,model configurations,and prediction variables.Nash-Sutcliffe Efficiencies for uncalibrated simulations of uniform conditions were generally greater than 0.6 except for soluble nitrogen predictions which were poor.Simulations of nonuniform conditions were generally'unsatisfactory'except for runoff predictions which were quite good(NSE=0.78).Performance was improved substantially for almost all endpoints with calibration.Some exceptions to this occurred because the objective function for calibration was based on log-space differences so as to more equally-weight calibration of unsaturated conditions that tend to produce lesser runoff volumes and sediment yields.Calibrated results for both uniform and nonuniform condi-tions were generally'satisfactory'or'good'according to widely accepted model performance criteria.展开更多
Conservation practices are encouraged to improve soil health and sustain agronomic crop production.Mehlich-3 is often used as a multi-nutrient extractant to determine soil fertility status.A study inves-tigated the im...Conservation practices are encouraged to improve soil health and sustain agronomic crop production.Mehlich-3 is often used as a multi-nutrient extractant to determine soil fertility status.A study inves-tigated the impacts of the conservation practices of gypsum,cover crops,and crop rotation on 28 Mehlich-3 extractable elements,of which 11 were considered plant nutrients,from soil at three mid-western US locations.Soil was collected from 0 to 15 and 15-30 cm depths 5 years after implementing the conservation practices.Treatments consisted of(1)with and without cereal rye(Secale cereale L.)winter cover,(2)continuous soybean[Glycine max(L.)Merr.]vs.soybean-corn(Zea mays L.)rotation,and(3)annual gypsum application(0,1.1,and 2.2 Mg ha-1).Differences were observed by site,depth,and conservation practice depending on the element evaluated.Minimal interactive effects were observed among treatments.The most consistent effect was observed for crop rotation across sites.Gypsum only affected the site with the greatest clay content,where more Ca and S were retained,and Mg and Mn displaced.Cover crop only affected elements at this high clay site,where different elements were positively or negatively affected.Results suggest that not one practice fits all,and optimum conservation practices must be tailored for the site.展开更多
Socioeconomic and environmental losses caused by water erosion have highlighted the importance of quantifying and understanding the dynamics of soil redistribution in the landscape to develop effective soil management...Socioeconomic and environmental losses caused by water erosion have highlighted the importance of quantifying and understanding the dynamics of soil redistribution in the landscape to develop effective soil management practices.Several methods are applied to estimate erosion/deposition rates and identify sources of sediments,among them,the one that uses rare earth elements(REE)as a tracer stands out.However,an alternative not yet explored that can benefit the accuracy of the estimates provided by the method is using a tracer containing a chemical signature composed of more than one REE.The present study aimed to evaluate the performance of a new water erosion tracer based on montmoril-lonite labeled with rare earth elements(La40-MMT).The innovative aspects of this La40-MMT tracer include its highly stable multi-chemical signature(Nd^(3+),La^(3+),and Pr^(3+)),which enhances tracer detection in the environment,and its low production cost due to the use of an industrial residue in the synthesis process.The tracer was evaluated for a typical soil of the Cerrado biome,using a natural rainfall field-scale plot-NRFP(5 m × 20 m)and a physical predictive erosion model(WEPP).The results showed that the La40-MMT tracer could be used to estimate erosion/deposition rates,with agreement between the values observed with the tracer and the WEPP model.Thus,this study confirmed the great potential of La40-MMT as a tool to identify patterns of soil redistribution at the field scale and aid in the validation of erosion models.展开更多
The Water Erosion Prediction Project(WEPP)model has been widely used for estimating runoff and soil loss.The evaluation of the latest version(version 2021.133)under a range of environmental conditions can provide conf...The Water Erosion Prediction Project(WEPP)model has been widely used for estimating runoff and soil loss.The evaluation of the latest version(version 2021.133)under a range of environmental conditions can provide confidence to its users.The objectives of this study were to evaluate the WEPP model for runoff and soil loss predictions using 1159 plot years of rainfall-runoff events data from field experi-mental plots with various climates,soils,topographies,and crops.WEPP runoff and soil loss predictions were compared to the observations before and after input parameter calibration.The results showed good predictions of runoff and soil loss were obtained with both the uncalibrated and calibrated WEPP model for all considered scales with Nash-Sutcliffe model efficiencies(NSE)over 0.4.The calibration of input baseline effective hydraulic conductivity(k_(e)),baseline critical shear stress(τ_(c)),baseline rill erod-ibility(k_(r)),and baseline interrill erodibility(k_(i))improved WEPP model performance with NSE values of 0.98 and 0.91 for average annual runoff and soil loss predictions,respectively.The WEPP model tended to underestimate the runoff and soil loss for large events with runoff over 100 mm and soil loss over 120t/ha.Good event runoff and soil loss predictions(NSE ≥0.4)were obtained for the most common cropping/management systems considered,including corn,cotton,tilled fallow,and wheat after calibration.This study illustrates the most recent WEPP model's performance for runoff and soil loss predictions,and provides a comprehensive set of results.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
Maps of erosivity,which are also commonly referred to as isoerodent maps,have played a critical role in soil conservation efforts in the United States and around the world.Currently available erosivity maps for the Un...Maps of erosivity,which are also commonly referred to as isoerodent maps,have played a critical role in soil conservation efforts in the United States and around the world.Currently available erosivity maps for the United States are either outdated,conflict with erosivity benchmarking studies,or utilized less advanced spatial mapping methods.Furthermore,it is possible that the same underlying issues with US maps are impacting global maps as well.In this study,we used more than 340015-min,fixed-interval precipitation gauges to update the isoerodent map of the conterminous United States.Erosivity values were interpolated using universal kriging under several spatial model configurations and resolutions.The optimal spatial model was selected based on which result had the lowest sample variogram error.Rainfall,erosivity,and erosivity density maps were compared to existing products.Some average annual and annual erosivity results were compared to high-quality erosivity benchmarking publications.Erosivity values from both RUSLE2 and Panagos et al.(2017)were generally lower in the eastern United States and mixed in the western United States compared to our results.Topographic effects resulted in much greater erosivity differences in this study as compared to prior maps.Benchmark comparisons revealed that erosivity maps from this study and others were lower than the benchmark by 14%or more(up to 38%).These findings suggest current practices of storm omission and intensity dampening correction need to be revisited,especially in locations with relatively low-to-moderate rainfall erosivity such as the Midwest or Northeast United States,for example.展开更多
In order to design Sustainable Land Management(SLM)plans or interventions it is important to understand the land use change and subsequent impacts.The basic aim of this study was to assess the impact of land use land ...In order to design Sustainable Land Management(SLM)plans or interventions it is important to understand the land use change and subsequent impacts.The basic aim of this study was to assess the impact of land use land cover(LULC)change on soil physico-chemical properties and nutrients loss under different land use/land cover changes within Miandam watershed of Swat valley,Pakistan.The study area was divided into three major types on the basis LULC type(Dense forest,Moderate forest and Agriculture land).A total of 81 soil samples were collected from the study area(27 from each land use)through stratified random sampling and were transferred to the laboratory.The prepared soil samples were then tested for various physico-chemical properties such as pH,electrical conductivity,contents of organic matter,organic carbon,sand,silt,clay,nitrogen,phosphorus,potassium,iron,copper and zinc.Results showed that LULC significantly affected all soil parameters except electrical conductivity and potassium.For all the nutrients assessed,the enrichment ratio was greater than 1 which showed that the most fertile layer of the soil in the cropped areas was transported through soil erosion.In this study,time-series satellite images were used to determine the spatiotemporal changes in the LULC of Miandam valley of Swat,Pakistan,and the possible effect of LULC on soil properties was reported.The information generated on the soil properties as indicators of soil health could be used to inform the stakeholders about the effect of LULC change in the study area.Multi-temporal image acquired by Landsat sensors for the year 2018 was used for quantifying changes in the study area.The Landsat images for the year 2018 were classified into six land cover/land use classes.The increase in agricultural activities caused an increase in the land farming areas which led to an increase in the rate of deforestation in the valley.Thus,the present study results reveal that the use of the soil for agriculture instead of keeping them naturally or in other words changes in the land use land cover affects the soil physico-chemical properties and the overall nutrients availability.展开更多
The soil erosion research and soil and water conservation global community lost a treasured member on November 20,2020,when Dr.John Matthew Laflen(Fig.1)died.Always one with a friendly welcoming smile,John had hundred...The soil erosion research and soil and water conservation global community lost a treasured member on November 20,2020,when Dr.John Matthew Laflen(Fig.1)died.Always one with a friendly welcoming smile,John had hundreds of friends,both personally and professionally throughout the world.This article includes many of his professional and scientific contributions,and impacts from his research and outreach activities.展开更多
文摘Current watershed-scale,nonpoint source pollution models do not represent the processes and impacts of agricultural best management practices on water quality with sufficient detail.A Water Erosion Pre-diction Project-Water Quality(WEPP-WQ)model was recently developed which is capable of simulating nonpoint source pollutant transport in nonuniform hillslope conditions such as those with BMPs.However,WEPP-WQ has not been validated for these conditions,and prior validation work only eval-uated calibrated performance rather than uncalibrated performance,with the latter being most relevant to model applications.This study evaluated uncalibrated and calibrated model performance in two plot-scale,artificial rainfall studies.179 observations were compared to corresponding WEPP-WQ simulations of runoff,sediment yield,and soluble and particulate nutrient forms for both nitrogen and phosphorus.Uncalibrated validation results were mixed for the different field conditions,model configurations,and prediction variables.Nash-Sutcliffe Efficiencies for uncalibrated simulations of uniform conditions were generally greater than 0.6 except for soluble nitrogen predictions which were poor.Simulations of nonuniform conditions were generally'unsatisfactory'except for runoff predictions which were quite good(NSE=0.78).Performance was improved substantially for almost all endpoints with calibration.Some exceptions to this occurred because the objective function for calibration was based on log-space differences so as to more equally-weight calibration of unsaturated conditions that tend to produce lesser runoff volumes and sediment yields.Calibrated results for both uniform and nonuniform condi-tions were generally'satisfactory'or'good'according to widely accepted model performance criteria.
基金support provided by United Soybean Board Project Number 1520-732-7226by state and federal funds appropriated to The Ohio State University and The Ohio Agricultural Research and Development Center。
文摘Conservation practices are encouraged to improve soil health and sustain agronomic crop production.Mehlich-3 is often used as a multi-nutrient extractant to determine soil fertility status.A study inves-tigated the impacts of the conservation practices of gypsum,cover crops,and crop rotation on 28 Mehlich-3 extractable elements,of which 11 were considered plant nutrients,from soil at three mid-western US locations.Soil was collected from 0 to 15 and 15-30 cm depths 5 years after implementing the conservation practices.Treatments consisted of(1)with and without cereal rye(Secale cereale L.)winter cover,(2)continuous soybean[Glycine max(L.)Merr.]vs.soybean-corn(Zea mays L.)rotation,and(3)annual gypsum application(0,1.1,and 2.2 Mg ha-1).Differences were observed by site,depth,and conservation practice depending on the element evaluated.Minimal interactive effects were observed among treatments.The most consistent effect was observed for crop rotation across sites.Gypsum only affected the site with the greatest clay content,where more Ca and S were retained,and Mg and Mn displaced.Cover crop only affected elements at this high clay site,where different elements were positively or negatively affected.Results suggest that not one practice fits all,and optimum conservation practices must be tailored for the site.
文摘Socioeconomic and environmental losses caused by water erosion have highlighted the importance of quantifying and understanding the dynamics of soil redistribution in the landscape to develop effective soil management practices.Several methods are applied to estimate erosion/deposition rates and identify sources of sediments,among them,the one that uses rare earth elements(REE)as a tracer stands out.However,an alternative not yet explored that can benefit the accuracy of the estimates provided by the method is using a tracer containing a chemical signature composed of more than one REE.The present study aimed to evaluate the performance of a new water erosion tracer based on montmoril-lonite labeled with rare earth elements(La40-MMT).The innovative aspects of this La40-MMT tracer include its highly stable multi-chemical signature(Nd^(3+),La^(3+),and Pr^(3+)),which enhances tracer detection in the environment,and its low production cost due to the use of an industrial residue in the synthesis process.The tracer was evaluated for a typical soil of the Cerrado biome,using a natural rainfall field-scale plot-NRFP(5 m × 20 m)and a physical predictive erosion model(WEPP).The results showed that the La40-MMT tracer could be used to estimate erosion/deposition rates,with agreement between the values observed with the tracer and the WEPP model.Thus,this study confirmed the great potential of La40-MMT as a tool to identify patterns of soil redistribution at the field scale and aid in the validation of erosion models.
文摘The Water Erosion Prediction Project(WEPP)model has been widely used for estimating runoff and soil loss.The evaluation of the latest version(version 2021.133)under a range of environmental conditions can provide confidence to its users.The objectives of this study were to evaluate the WEPP model for runoff and soil loss predictions using 1159 plot years of rainfall-runoff events data from field experi-mental plots with various climates,soils,topographies,and crops.WEPP runoff and soil loss predictions were compared to the observations before and after input parameter calibration.The results showed good predictions of runoff and soil loss were obtained with both the uncalibrated and calibrated WEPP model for all considered scales with Nash-Sutcliffe model efficiencies(NSE)over 0.4.The calibration of input baseline effective hydraulic conductivity(k_(e)),baseline critical shear stress(τ_(c)),baseline rill erod-ibility(k_(r)),and baseline interrill erodibility(k_(i))improved WEPP model performance with NSE values of 0.98 and 0.91 for average annual runoff and soil loss predictions,respectively.The WEPP model tended to underestimate the runoff and soil loss for large events with runoff over 100 mm and soil loss over 120t/ha.Good event runoff and soil loss predictions(NSE ≥0.4)were obtained for the most common cropping/management systems considered,including corn,cotton,tilled fallow,and wheat after calibration.This study illustrates the most recent WEPP model's performance for runoff and soil loss predictions,and provides a comprehensive set of results.
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.
文摘Maps of erosivity,which are also commonly referred to as isoerodent maps,have played a critical role in soil conservation efforts in the United States and around the world.Currently available erosivity maps for the United States are either outdated,conflict with erosivity benchmarking studies,or utilized less advanced spatial mapping methods.Furthermore,it is possible that the same underlying issues with US maps are impacting global maps as well.In this study,we used more than 340015-min,fixed-interval precipitation gauges to update the isoerodent map of the conterminous United States.Erosivity values were interpolated using universal kriging under several spatial model configurations and resolutions.The optimal spatial model was selected based on which result had the lowest sample variogram error.Rainfall,erosivity,and erosivity density maps were compared to existing products.Some average annual and annual erosivity results were compared to high-quality erosivity benchmarking publications.Erosivity values from both RUSLE2 and Panagos et al.(2017)were generally lower in the eastern United States and mixed in the western United States compared to our results.Topographic effects resulted in much greater erosivity differences in this study as compared to prior maps.Benchmark comparisons revealed that erosivity maps from this study and others were lower than the benchmark by 14%or more(up to 38%).These findings suggest current practices of storm omission and intensity dampening correction need to be revisited,especially in locations with relatively low-to-moderate rainfall erosivity such as the Midwest or Northeast United States,for example.
文摘In order to design Sustainable Land Management(SLM)plans or interventions it is important to understand the land use change and subsequent impacts.The basic aim of this study was to assess the impact of land use land cover(LULC)change on soil physico-chemical properties and nutrients loss under different land use/land cover changes within Miandam watershed of Swat valley,Pakistan.The study area was divided into three major types on the basis LULC type(Dense forest,Moderate forest and Agriculture land).A total of 81 soil samples were collected from the study area(27 from each land use)through stratified random sampling and were transferred to the laboratory.The prepared soil samples were then tested for various physico-chemical properties such as pH,electrical conductivity,contents of organic matter,organic carbon,sand,silt,clay,nitrogen,phosphorus,potassium,iron,copper and zinc.Results showed that LULC significantly affected all soil parameters except electrical conductivity and potassium.For all the nutrients assessed,the enrichment ratio was greater than 1 which showed that the most fertile layer of the soil in the cropped areas was transported through soil erosion.In this study,time-series satellite images were used to determine the spatiotemporal changes in the LULC of Miandam valley of Swat,Pakistan,and the possible effect of LULC on soil properties was reported.The information generated on the soil properties as indicators of soil health could be used to inform the stakeholders about the effect of LULC change in the study area.Multi-temporal image acquired by Landsat sensors for the year 2018 was used for quantifying changes in the study area.The Landsat images for the year 2018 were classified into six land cover/land use classes.The increase in agricultural activities caused an increase in the land farming areas which led to an increase in the rate of deforestation in the valley.Thus,the present study results reveal that the use of the soil for agriculture instead of keeping them naturally or in other words changes in the land use land cover affects the soil physico-chemical properties and the overall nutrients availability.
文摘The soil erosion research and soil and water conservation global community lost a treasured member on November 20,2020,when Dr.John Matthew Laflen(Fig.1)died.Always one with a friendly welcoming smile,John had hundreds of friends,both personally and professionally throughout the world.This article includes many of his professional and scientific contributions,and impacts from his research and outreach activities.
