SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Validation of a quantitative phosphorus loss assessment tool 
Authors:White, M.J., D.E. Storm, M.D. Smolen, P.R. Busteed, H. Zhang and G.A. Fox 
Journal:Journal of Environmental Quality 
Volume (Issue):43(1) 
Article ID: 
URL (non-DOI journals): 
Model:SWAT (modified) 
Broad Application Category:hydrologic and pollutant 
Primary Application Category:GIS interface, GIS utility, or other type of interface/utility 
Secondary Application Category:phosphorus cycling/loss and transport 
Watershed Description:A total of 286 field-years of data from 63 field sites located in Oklahoma, Texas, Arkansas, and Georgia. 
Calibration Summary: 
Validation Summary: 
General Comments:This article is part of a JEQ special SWAT section. The authors initially report 435 field years of data but this was ultimately reduced to 286 filed years of data for model calibration and validation efforts, due to various factors they describe in their study. 
Abstract:Pasture Phosphorus Management Plus (PPM Plus) is a tool that allows nutrient management and conservation planners to evaluate phosphorus loss from agricultural fields. This tool uses a modified version of the widely used Soil and Water Assessment Tool (SWAT) model with a vastly simplified interface. The development of PPM Plus has been fully described in previous publications; in this article we evaluate the accuracy of PPM Plus using 286 field-years of runoff, sediment, and phosphorus validation data from runoff studies at various locations in Oklahoma, Texas, Arkansas, and Georgia. Land uses include pasture, small grains, and row crops with rainfall ranging from 630 to 1390 mm yr-1, with and without animal manure application. PPM Plus explained 68% of the variability in total phosphorus loss, 56% of runoff, and 73% of the variability of sediment yield. An empirical model developed from these data using Soil Test Phosphorus (STP), total applied phosphorus, slope, and precipitation only accounted for 15% of the variability in total phosphorus loss; which implies that a process-based model is required to account for the diversity present in these data. PPM Plus is an easy-to-use conservation planning tool for P loss prediction, which with modification, could be applicable at the regional and national scales.