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Nitrogen Component in Nonpoint Source Pollution Models
Citation:
Yuan, Y., R. Bingner, AND H. Momm. Nitrogen Component in Nonpoint Source Pollution Models. Chapter 2, Precision Conservation: Geospatial Techniques for Agricultural and Natural Resources Conservation. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Madison, WI, , 27-64, (2018).
Impact/Purpose:
A chapter in the book, Precision Conservation: Geospatial Techniques for Agricultural and Natural Resources Conservation
Description:
Pollutants entering a water body can be very destructive to the health of that system. Best Management Practices (BMPs) and/or conservation practices are used to reduce these pollutants, but understanding the most effective practices is very difficult. Watershed models are an effective tool to aid in the decision making process of selecting the BMPs that are most effective in reducing the pollutant loading and are also the most cost effective. The Erosion-Productivity Index Calculator (EPIC), now the Agricultural Policy/Environmental eXtender (APEX) for application at field scale, the Annualized Agricultural Nonpoint Source pollution (AnnAGNPS) and the Soil and Water Assessment Tool (SWAT) for application at watershed scale have been developed as technological tools for evaluation of the impact of agricultural management practices on water quality and long-term soil productivity. Evaluation of model performance at various scales and locations demonstrated mixed results due to the complexity of nitrogen processes. In this book chapter, nitrogen processes simulated in each model were reviewed and compared. Furthermore, current research on nitrogen losses from agricultural fields were also reviewed. Finally, applications with those models were reviewed and selected successful and unsuccessful stories were described. Although components of the N cycle included in each model varied, there are a lot of similarities in simulating N processes. The estimation of nitrogen loss at the watershed scale is a complex problem; nonpoint source pollution models need to be further improved, and novel technology is still needed to integrate nutrient models with hydrological and erosion models.