Skip to main content

Person

Stephen D Preston

thumbnail
This dataset includes all of the variables that were used in predictive models to estimate nitrogen and phosphorus fertilizer use from commercial fertilizer sales data at the catchment/county level for the Conterminous U.S. for the year 2012. The dataset includes model input at the catchment/county level. A companion USGS Scientific Investigations Report describes the methods and subsequent results of two models developed for estimating elemental nitrogen and phosphorus commercial fertilizer use on agricultural lands for the conterminous US at the catchment/county scale for the year 2012. A companion data release provides catchment-level estimates of nitrogen and phosphorus fertilizer use, for agricultural lands,...
thumbnail
This dataset contains catchment-level estimates of nitrogen and phosphorus fertilizer use, for agricultural lands, for the conterminous U.S., for 2012. An approach was developed to relate farm commercial fertilizer sales data from the Association of American Plant Food Control Officials (AAPFCO) to a set of explanatory variables using spatially-referenced modeling methods. Separate models for nitrogen and phosphorus are developed to estimate elemental fertilizer use on agricultural lands for the conterminous U.S. at the National Hydrography Dataset Plus version 2 (NHDPlusV2) catchment scale. The approach builds on earlier efforts that use Association of American Plant Food Control Officials (AAPFCO) data on fertilizer...
thumbnail
The United States Geological Survey’s (USGS) SPAtially Referenced Regressions On Watershed attributes (SPARROW) model was developed to aid in the interpretation of monitoring data and simulate water-quality conditions in streams across large spatial scales. SPARROW is a hybrid empirical/process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based streamflow...
ScienceBase brings together the best information it can find about USGS researchers and offices to show connections to publications, projects, and data. We are still working to improve this process and information is by no means complete. If you don't see everything you know is associated with you, a colleague, or your office, please be patient while we work to connect the dots. Feel free to contact sciencebase@usgs.gov.