Larry Wagner - Academia.edu (original) (raw)

Papers by Larry Wagner

Research paper thumbnail of Military Vehicle Trafficking Impacts on Vegetation and Soil Bulk Density at Fort Benning, Georgia

Transactions of the ASABE, Aug 22, 2014

Research paper thumbnail of Methods for Investigating Basic Processes and Conditions Affecting Wind Erosion

Research paper thumbnail of Measurement and Modeling of Fugitive Dust from Off Road DoD Activities

Research paper thumbnail of Effects of overwinter processes on stability of dry soil aggregates

Soil erosion research for the 21st century. Proceedings of the International Symposium, Honolulu, Hawaii, USA, 3-5 January, 2001., 2001

ABSTRACT Changes in soil surface aggregation during winter can result in surface conditions highl... more ABSTRACT Changes in soil surface aggregation during winter can result in surface conditions highly susceptible or resistant to wind erosion, depending on the type and severity of the overwinter processes. The effects of wet/dry, freeze/thaw, and freeze/dry processes on soil dry aggregate stability were studied in laboratory environmental chambers. Aggregates (13-19 mm dia.) were sampled before winter from five field soils that were selected to provide a variety in physical and chemical properties. Each was analyzed for five sand fractions, two silt fractions, clay, wet and dry bulk density, coefficient of linear extensibility (COLE), exchangeable calcium and magnesium, and organic matter. Aggregates were wetted to water contents approximately equal to saturation, field capacity, wilting point, and air dry. They then were subjected to increasing numbers of cycles of the overwintering processes, and the dry stability of the resulting aggregates was related to the soil properties, the process, and the number of cycles. Results indicated that under wet/dry and freeze/thaw processes high water content of aggregates increase stability, whereas lower water contents result in less stability. The freeze/dry process resulted in less stable aggregates regardless of water content. Increasing the number of process cycles tended to increase the level of response to all processes. These results will further our ability to predict changes in soil aggregates in response to overwintering.

Research paper thumbnail of Comparison of the Weibull Model with Measured Wind Speed Distributions for Stochastic Wind Generation

Transactions of the ASAE, 2005

Research paper thumbnail of The Wind Erosion Prediction System and its Use in Conservation Planning

Advances in agricultural systems modeling, Jan 15, 2019

Research paper thumbnail of Dune sand transport as influenced by wind directions, speed and frequencies in the Ordos Plateau, China

Geomorphology, Apr 1, 2005

Research paper thumbnail of WEPS 1.0 - What It Is and What It Isn't

Research paper thumbnail of Military vehicle trafficking impacts vegetation and soil bulk density at Fort Benning, Georgia

Abstract. Potential increases in wind erosion that might be brought about by military vehicles tr... more Abstract. Potential increases in wind erosion that might be brought about by military vehicles travelling off-road during training are of concern to the United States military. Field studies were conducted in the summer of 2012 at Fort Benning, Georgia. The objective of the experiment was to assess the trafficked surface changes in susceptibility to generating dust emissions due to military vehicle trafficking intensity. Site-specific quantitative data on the major soil and vegetation parameters are needed to make appropriate estimates of the susceptibility to dust generation from the soil surface and the magnitude of those emissions. The field experiment consisted of carrying out multiple trafficking passes with both tracked and wheeled vehicles. A tracked (M1A1) and wheeled (HMMWV) vehicle were driven in a figure-8 pattern in 40-m A— 70-m plots. On each plot, three levels of vehicle passes were made. On the tracked plots, the M1A1 was driven a total cumulative number of passes of 1, 5, and 10. On the wheeled plots, the HMMWV was driven a total cumulative number of passes of 10, 25, and 50. The vehicles were driven repeatedly over the same figure-8 path. The statistical design consisted of vehicle type in the main plots in three replications and vehicle passes as repeated measures. Bulk density, aboveground biomass, and vegetative cover data were taken from the straight, curved, and cross-over sections of the vehicle tracks. Samples were also taken before the start of trafficking. Bulk density at three depths, total aboveground biomass, grass biomass, forb biomass, biomass by individual species, total cover, grass cover, and forb cover data were analyzed for differences between vehicles, vehicles passes, locations within the track sections, and their interactions. All grass and forb species suffered from 65% to 100% reduction in biomass. After trafficking, the biomass difference between vehicles was not significant. However, cover showed strong response to vehicle type, trafficking intensity, location (within the vehicle tracks), and their interactions. Regression equations relating trafficking intensity to reduction in cover were obtained. These equations could be used to give reasonable estimates of the loss of cover resulting from trafficking by tracked or wheeled vehicles. At the 5 cm depth bulk density was significantly higher than the control in both the M1A1 and HMMWV tracks. There was no significant evidence of soil compaction below 5 cm.

Research paper thumbnail of Fugitive Dust Emissions from Off-road Vehicle Maneuvers on Military Training Lands

2013 Kansas City, Missouri, July 21 - July 24, 2013, 2013

Research paper thumbnail of Evaluation of Bulk Density and Vegetation as Affected by Military Vehicle Traffic at Fort Riley, Kansas

Transactions of the ASABE, 2013

Research paper thumbnail of Unified Plant Growth Model (UPGM). 2. Component development and integration with agroecosystem models

Research paper thumbnail of An Introduction to the Wind Erosion Prediction System (WEPS)

Research paper thumbnail of Demonstration of the WEPS 1.0 wind erosion model

Research paper thumbnail of WebStart WEPS: WEPS with Remote Data Access and Cloud-Computing Functionality

Journal of the ASABE

HighlightsWebStart WEPS is a Java WebStart enabled browser-accessible version of WEPS.This model-... more HighlightsWebStart WEPS is a Java WebStart enabled browser-accessible version of WEPS.This model-as-a-service cloud-based system provides remote access to model inputs and remote model execution.Default QuickPlot reports are provided to quickly visualize model results.MapViewer revisions are provided to improve map-based site selections.. The Wind Erosion Prediction System (WEPS) is a physical process-based wind erosion model developed by the USDA Agricultural Research Service (USDA-ARS). WEPS simulates daily climate and management-driven changes to the surface, vegetation, and soil. It estimates erosion losses when surface conditions and wind speeds are sufficient for soil movement. WEPS was released in 2010 to the USDA Natural Resources Conservation Service (USDA-NRCS) for assisting land managers in controlling wind erosion, establishing field-level plans for soil conservation, and determining wind erosion susceptibility as a part of national conservation programs to conserve the ...

Research paper thumbnail of Tillage-Induced Soil Aggregate Status as Influenced by Water Content

Transactions of the ASAE, 1992

Research paper thumbnail of Evaluation of Bulk Density and Vegetation as Affected by Military Vehicle Traffic

International Symposium on Erosion and Landscape Evolution (ISELE), 18-21 September 2011, Anchorage, Alaska, 2011

Research paper thumbnail of Analytical Solutions and Sensitivity Analyses for Sediment Transport in Weps

Transactions of the ASAE, 1999

Research paper thumbnail of Effects of Overwinter Processes on Stability of Dry Soil Aggregates

Soil Erosion

ABSTRACT Changes in soil surface aggregation during winter can result in surface conditions highl... more ABSTRACT Changes in soil surface aggregation during winter can result in surface conditions highly susceptible or resistant to wind erosion, depending on the type and severity of the overwinter processes. The effects of wet/dry, freeze/thaw, and freeze/dry processes on soil dry aggregate stability were studied in laboratory environmental chambers. Aggregates (13-19 mm dia.) were sampled before winter from five field soils that were selected to provide a variety in physical and chemical properties. Each was analyzed for five sand fractions, two silt fractions, clay, wet and dry bulk density, coefficient of linear extensibility (COLE), exchangeable calcium and magnesium, and organic matter. Aggregates were wetted to water contents approximately equal to saturation, field capacity, wilting point, and air dry. They then were subjected to increasing numbers of cycles of the overwintering processes, and the dry stability of the resulting aggregates was related to the soil properties, the process, and the number of cycles. Results indicated that under wet/dry and freeze/thaw processes high water content of aggregates increase stability, whereas lower water contents result in less stability. The freeze/dry process resulted in less stable aggregates regardless of water content. Increasing the number of process cycles tended to increase the level of response to all processes. These results will further our ability to predict changes in soil aggregates in response to overwintering.

Research paper thumbnail of Standardizing Cropping System Data for Integrated Agricultural Resource Assessment

Approximately 40 percent of the land in the United States is farmland, about 370 million hectares... more Approximately 40 percent of the land in the United States is farmland, about 370 million hectares. Farmers cultivate 158 million hectares, making daily decisions to improve the productivity of their land. Through technical assistance program providers and agricultural retail consultants, they use several tools to assess the sustainability of their operations, analyzing soil health, water management, agricultural chemical inputs, energy use, among other concerns. These tools currently provide more than 1 million assessments annually on farm fields across the country, including models and metamodels estimating water and wind erosion, soil organic matter trend, farm fuel use, nutrient and pesticide loss potentials, nutrient balance, PM10 air particulates (dust), soil carbon and nitrogen sequestration. The tools operate from common national soil and climate data. Central to on-farm analysis is the cropping system applied by the farmer. With many programs and initiatives supporting asses...

Research paper thumbnail of Military Vehicle Trafficking Impacts on Vegetation and Soil Bulk Density at Fort Benning, Georgia

Transactions of the ASABE, Aug 22, 2014

Research paper thumbnail of Methods for Investigating Basic Processes and Conditions Affecting Wind Erosion

Research paper thumbnail of Measurement and Modeling of Fugitive Dust from Off Road DoD Activities

Research paper thumbnail of Effects of overwinter processes on stability of dry soil aggregates

Soil erosion research for the 21st century. Proceedings of the International Symposium, Honolulu, Hawaii, USA, 3-5 January, 2001., 2001

ABSTRACT Changes in soil surface aggregation during winter can result in surface conditions highl... more ABSTRACT Changes in soil surface aggregation during winter can result in surface conditions highly susceptible or resistant to wind erosion, depending on the type and severity of the overwinter processes. The effects of wet/dry, freeze/thaw, and freeze/dry processes on soil dry aggregate stability were studied in laboratory environmental chambers. Aggregates (13-19 mm dia.) were sampled before winter from five field soils that were selected to provide a variety in physical and chemical properties. Each was analyzed for five sand fractions, two silt fractions, clay, wet and dry bulk density, coefficient of linear extensibility (COLE), exchangeable calcium and magnesium, and organic matter. Aggregates were wetted to water contents approximately equal to saturation, field capacity, wilting point, and air dry. They then were subjected to increasing numbers of cycles of the overwintering processes, and the dry stability of the resulting aggregates was related to the soil properties, the process, and the number of cycles. Results indicated that under wet/dry and freeze/thaw processes high water content of aggregates increase stability, whereas lower water contents result in less stability. The freeze/dry process resulted in less stable aggregates regardless of water content. Increasing the number of process cycles tended to increase the level of response to all processes. These results will further our ability to predict changes in soil aggregates in response to overwintering.

Research paper thumbnail of Comparison of the Weibull Model with Measured Wind Speed Distributions for Stochastic Wind Generation

Transactions of the ASAE, 2005

Research paper thumbnail of The Wind Erosion Prediction System and its Use in Conservation Planning

Advances in agricultural systems modeling, Jan 15, 2019

Research paper thumbnail of Dune sand transport as influenced by wind directions, speed and frequencies in the Ordos Plateau, China

Geomorphology, Apr 1, 2005

Research paper thumbnail of WEPS 1.0 - What It Is and What It Isn't

Research paper thumbnail of Military vehicle trafficking impacts vegetation and soil bulk density at Fort Benning, Georgia

Abstract. Potential increases in wind erosion that might be brought about by military vehicles tr... more Abstract. Potential increases in wind erosion that might be brought about by military vehicles travelling off-road during training are of concern to the United States military. Field studies were conducted in the summer of 2012 at Fort Benning, Georgia. The objective of the experiment was to assess the trafficked surface changes in susceptibility to generating dust emissions due to military vehicle trafficking intensity. Site-specific quantitative data on the major soil and vegetation parameters are needed to make appropriate estimates of the susceptibility to dust generation from the soil surface and the magnitude of those emissions. The field experiment consisted of carrying out multiple trafficking passes with both tracked and wheeled vehicles. A tracked (M1A1) and wheeled (HMMWV) vehicle were driven in a figure-8 pattern in 40-m A— 70-m plots. On each plot, three levels of vehicle passes were made. On the tracked plots, the M1A1 was driven a total cumulative number of passes of 1, 5, and 10. On the wheeled plots, the HMMWV was driven a total cumulative number of passes of 10, 25, and 50. The vehicles were driven repeatedly over the same figure-8 path. The statistical design consisted of vehicle type in the main plots in three replications and vehicle passes as repeated measures. Bulk density, aboveground biomass, and vegetative cover data were taken from the straight, curved, and cross-over sections of the vehicle tracks. Samples were also taken before the start of trafficking. Bulk density at three depths, total aboveground biomass, grass biomass, forb biomass, biomass by individual species, total cover, grass cover, and forb cover data were analyzed for differences between vehicles, vehicles passes, locations within the track sections, and their interactions. All grass and forb species suffered from 65% to 100% reduction in biomass. After trafficking, the biomass difference between vehicles was not significant. However, cover showed strong response to vehicle type, trafficking intensity, location (within the vehicle tracks), and their interactions. Regression equations relating trafficking intensity to reduction in cover were obtained. These equations could be used to give reasonable estimates of the loss of cover resulting from trafficking by tracked or wheeled vehicles. At the 5 cm depth bulk density was significantly higher than the control in both the M1A1 and HMMWV tracks. There was no significant evidence of soil compaction below 5 cm.

Research paper thumbnail of Fugitive Dust Emissions from Off-road Vehicle Maneuvers on Military Training Lands

2013 Kansas City, Missouri, July 21 - July 24, 2013, 2013

Research paper thumbnail of Evaluation of Bulk Density and Vegetation as Affected by Military Vehicle Traffic at Fort Riley, Kansas

Transactions of the ASABE, 2013

Research paper thumbnail of Unified Plant Growth Model (UPGM). 2. Component development and integration with agroecosystem models

Research paper thumbnail of An Introduction to the Wind Erosion Prediction System (WEPS)

Research paper thumbnail of Demonstration of the WEPS 1.0 wind erosion model

Research paper thumbnail of WebStart WEPS: WEPS with Remote Data Access and Cloud-Computing Functionality

Journal of the ASABE

HighlightsWebStart WEPS is a Java WebStart enabled browser-accessible version of WEPS.This model-... more HighlightsWebStart WEPS is a Java WebStart enabled browser-accessible version of WEPS.This model-as-a-service cloud-based system provides remote access to model inputs and remote model execution.Default QuickPlot reports are provided to quickly visualize model results.MapViewer revisions are provided to improve map-based site selections.. The Wind Erosion Prediction System (WEPS) is a physical process-based wind erosion model developed by the USDA Agricultural Research Service (USDA-ARS). WEPS simulates daily climate and management-driven changes to the surface, vegetation, and soil. It estimates erosion losses when surface conditions and wind speeds are sufficient for soil movement. WEPS was released in 2010 to the USDA Natural Resources Conservation Service (USDA-NRCS) for assisting land managers in controlling wind erosion, establishing field-level plans for soil conservation, and determining wind erosion susceptibility as a part of national conservation programs to conserve the ...

Research paper thumbnail of Tillage-Induced Soil Aggregate Status as Influenced by Water Content

Transactions of the ASAE, 1992

Research paper thumbnail of Evaluation of Bulk Density and Vegetation as Affected by Military Vehicle Traffic

International Symposium on Erosion and Landscape Evolution (ISELE), 18-21 September 2011, Anchorage, Alaska, 2011

Research paper thumbnail of Analytical Solutions and Sensitivity Analyses for Sediment Transport in Weps

Transactions of the ASAE, 1999

Research paper thumbnail of Effects of Overwinter Processes on Stability of Dry Soil Aggregates

Soil Erosion

ABSTRACT Changes in soil surface aggregation during winter can result in surface conditions highl... more ABSTRACT Changes in soil surface aggregation during winter can result in surface conditions highly susceptible or resistant to wind erosion, depending on the type and severity of the overwinter processes. The effects of wet/dry, freeze/thaw, and freeze/dry processes on soil dry aggregate stability were studied in laboratory environmental chambers. Aggregates (13-19 mm dia.) were sampled before winter from five field soils that were selected to provide a variety in physical and chemical properties. Each was analyzed for five sand fractions, two silt fractions, clay, wet and dry bulk density, coefficient of linear extensibility (COLE), exchangeable calcium and magnesium, and organic matter. Aggregates were wetted to water contents approximately equal to saturation, field capacity, wilting point, and air dry. They then were subjected to increasing numbers of cycles of the overwintering processes, and the dry stability of the resulting aggregates was related to the soil properties, the process, and the number of cycles. Results indicated that under wet/dry and freeze/thaw processes high water content of aggregates increase stability, whereas lower water contents result in less stability. The freeze/dry process resulted in less stable aggregates regardless of water content. Increasing the number of process cycles tended to increase the level of response to all processes. These results will further our ability to predict changes in soil aggregates in response to overwintering.

Research paper thumbnail of Standardizing Cropping System Data for Integrated Agricultural Resource Assessment

Approximately 40 percent of the land in the United States is farmland, about 370 million hectares... more Approximately 40 percent of the land in the United States is farmland, about 370 million hectares. Farmers cultivate 158 million hectares, making daily decisions to improve the productivity of their land. Through technical assistance program providers and agricultural retail consultants, they use several tools to assess the sustainability of their operations, analyzing soil health, water management, agricultural chemical inputs, energy use, among other concerns. These tools currently provide more than 1 million assessments annually on farm fields across the country, including models and metamodels estimating water and wind erosion, soil organic matter trend, farm fuel use, nutrient and pesticide loss potentials, nutrient balance, PM10 air particulates (dust), soil carbon and nitrogen sequestration. The tools operate from common national soil and climate data. Central to on-farm analysis is the cropping system applied by the farmer. With many programs and initiatives supporting asses...