A5040271545- Soil and Water Nutrient Dynamics
- Soil erosion and sediment transport
- Hydrology and Watershed Management Studies
- Phosphorus and nutrient management
- Wastewater Treatment and Nitrogen Removal
- Aquatic Ecosystems and Phytoplankton Dynamics
- Soil Carbon and Nitrogen Dynamics
- Agriculture Sustainability and Environmental Impact
- Cryospheric studies and observations
- Ruminant Nutrition and Digestive Physiology
- Odor and Emission Control Technologies
- Climate change and permafrost
- Constructed Wetlands for Wastewater Treatment
- Groundwater and Isotope Geochemistry
- Urban Stormwater Management Solutions
- Climate change impacts on agriculture
- Effects of Environmental Stressors on Livestock
- Biofuel production and bioconversion
- Crop Yield and Soil Fertility
- Soil and Unsaturated Flow
- Agricultural Innovations and Practices
- Turfgrass Adaptation and Management
- Bioenergy crop production and management
- Food Waste Reduction and Sustainability
- Organic Food and Agriculture
Beltsville Agricultural Research Center
2019-2024
Agricultural Research Service
2007-2021
United States Department of Agriculture
2005-2021
U.S. Dairy Forage Research Center
2008-2019
Waters (United States)
2004-2006
University of Delaware
1998-1999
Agricultural production in the United States is undergoing marked changes due to rapid shifts consumer demands, input costs, and concerns for food safety environmental impact. systems are comprised of multidimensional components drivers that interact complex ways influence sustainability. In a mixed-methods approach, we combine qualitative quantitative data develop simulate system dynamics model explores systemic interaction these on economic, social sustainability agricultural production....
ABSTRACT Phosphorus transport from agricultural soils contributes to eutrophication of fresh waters. Computer modeling can help identify areas with high potential P transport. Most models use a constant extraction coefficient (i.e., the slope linear regression between filterable reactive phosphorus [FRP] in runoff and soil P) predict dissolved release runoff, yet it is unclear how variations properties, management practices, or hydrology affect coefficients. We investigated published data 17...
Dairy farms in the United States are diverse and although regional dairy production farm strategy has been evaluated for environmental impact, a comprehensive national assessment is important to define priorities sustainable intensification. We estimated footprints of using process-level simulation cradle-to-farm gate life cycle assessment. representing sizes management practices found six regions were simulated with Integrated Farm System Model (IFSM). Regional determined as an average all...
Agricultural P transport in runoff is an environmental concern. An important source of surface-applied, unincorporated manures, but computer models used to assess do not adequately simulate release and from surface manures. We developed a model address this limitation. The operates on daily basis simulates manure application the soil surface, letting 60% infiltrate into if slurry with less than 15% solids applied. divides four pools, water-extractable inorganic organic P, stable P. dry...
Many states have invested significant resources to identify components of their Phosphorus (P) Index that reliably estimate the relative risk P loss and incentivize conservation management. However, differences in management recommendations manure application guidelines for similar field conditions among state Indices, coupled with minimal reductions extent P-impaired surface waters soil test (STP) levels, led U.S. Natural Resources Conservation Service (NRCS) revise 590 Nutrient Management...
Unnecessary accumulation of phosphorus (P) in agricultural soils continues to degrade water quality and linked ecosystem services. Managing both soil loss P fertility status is therefore crucial for eutrophication control, but the relative environmental benefits these two mitigation measures, timescales over which they occur, remain unclear. To support policies toward reduced loadings from soils, we examined impact conservation lowering test (STP) different regions with intensive farming...
ABSTRACT Evaluation of phosphorus (P) management strategies to protect water quality has largely relied on research using simulated rainfall generate runoff from either field plots or shallow boxes packed with soil. Runoff unmanured, grassed (1 m wide × 2 long, 3–8% slope) and bare soil (0.2 1 3% was compared simulation (75 mm h −1 ) standardized by 30‐min duration (rainfall averaged 55 for 41 boxes). Packed had lower infiltration (1.2 cm) greater (2.9 erosion (542 kg ha than (3.7 cm...
ABSTRACT Computer models are a rapid, inexpensive way to identify agricultural areas with high potential for P loss, but most poorly simulate dissolved release from surface‐applied manures runoff. We developed simple approach predict based on observed trends in laboratory extraction of dairy, poultry, and swine water over different manure ratios. The predicted well inorganic ( R 2 = 0.70) organic 0.73) composts data leaching experiments simulated rainfall. However, it 0.18) concentrations...
Nonpoint-source pollution of fresh waters by P is a concern because it contributes to accelerated eutrophication. Given the state science concerning agricultural transport, simple tool quantify annual, field-scale loss realistic goal. We developed new methods predict annual dissolved in runoff from surface-applied manures and fertilizers validated with data 21 published field studies. incorporated these manure fertilizer into an quantification that estimates particulate soil, manure,...
Abstract Process‐based models are increasingly used to study agroecosystem interactions and N 2 O emissions from agricultural fields. The widespread use of these conduct research inform policy benefits periodic model comparisons that assess the state modeling indicate areas for improvement. This work provides an evaluation simulated flux three process‐based models: DayCent, DNDC , EPIC . were calibrated validated using data collected two sites over five years represent cropping systems...
Watershed models such as the Soil Water Assessment Tool (SWAT) and Agricultural Policy Environmental EXtender (APEX) are widely used to assess fate transport of agricultural nutrient management practices on soluble particulate phosphorus (P) loss in runoff. P-cycling routines SWAT2012 revision 586, however, do not simulate short-term effects applying a concentrated source P, manure, soil surface where it is most vulnerable We added new set P 586 surface-applied manure at field subwatershed...
Vadas, Peter A., William E. Jokela, Dory H. Franklin, and Dinku M. Endale, 2011. The Effect of Rain Runoff When Assessing Timing Manure Application Dissolved Phosphorus Loss in Runoff. Journal the American Water Resources Association (JAWRA) 47(4):877-886. DOI: 10.1111/j.1752-1688.2011.00561.x Abstract: A significant pathway nonpoint source, agricultural phosphorus (P) transport is surface runoff, to which surface-applied manure can contribute. Increasing time between application first...
Phosphorus transfer from agricultural soils to surface waters is an important environmental issue. Commonly used models like SWAT have not always been updated reflect current understanding of soil P transformations and runoff. The objective this study was validate the ability routines in both SWAT2000 SWAT2005 initialize quantity different pools (and thus total P) simulate changes simulated solution pool. Based on data 40 published studies, results show that currently equations estimate PSP...
Agricultural phosphorus (P) management is a research and policy issue due to P loss from fields water quality degradation. Better information needed on the risk of dairy manure applied in winter or when runoff imminent. We used SurPhos computer model 108 site–years weather data assess impact these two practices dissolved loss. Model results showed that application can increase by 2.5 3.6 times compared with non‐winter applications, amount increasing as average field increases. Increased true...
Phosphorus in runoff from fields where poultry litter is surface-applied an environmental concern. We investigated the effect of adding phytase and reducing supplemental P diets composting manures, with without Fe Al amendments, on composts, runoff. used four diets: normal (no phytase) 0.4% P, + phytase, 0.3% 0.2% P. Adding decreasing reduced total but increased water-extractable manure. Compared both due to dilution manure woodchips straw, beyond a so that ratio was less compost than during...
Dissolved inorganic P transport in runoff from agricultural soils is an environmental concern. Models are used to predict but rarely simulate surface-applied manures. Using field-plot data, we tested a previously proposed model manure runoff. We updated the include more data relating water ratio released during extractions. verified that this update can release rain using published data. and soil-box three studies. The accurately predicted for boxes, underpredicted plots. Underpredictions...