Phosphorus and Nitrogen Loss Efficiencies Based on Nutrient Management Planning

The PI’s are Drs. Robert Hill, A. Shirmohammadi and P. Steinhilber. Support for this project came from a competitive grant from US Environmental Protection Agency with a funding amount of $238,500. The duration is from 2006-2009.

Modeling has been extensively used in the past when estimating nutrient loads to the Chesapeake Bay. Perceived reductions in phosphorus and nitrogen loads entering the Chesapeake Bay attributed to the implementation of agricultural best management practices (BMPs) are largely based on modeling the nutrient reduction impacts of these BMPs. The estimated reduction in nutrients is calculated using a nutrient loss efficiency coefficient specific for that best management practice. Many of these coefficients have not been field-tested and bring into question the validity of the estimated nutrient load reductions.

A rainfall simulation study will be conducted to evaluate the effects of various nitrogen based and phosphorus-based best management practices commonly utilized during nutrient management planning in the Chesapeake Bay watershed. Differences in P and N losses from organic versus fertilizer sources as well as the impacts of incorporation and manure type will be evaluated. Subsurface transport of nutrients will also be monitored for the various nutrient management treatments. The resultant data will then be used in combination with previously published research results to calibrate a watershed field model for the estimation of P and N losses and determination of nutrient loss efficiencies.

This project is currently underway and starting the second year of the project. It is hoped that the research will result in new nutrient reduction loss efficiencies that may be used by modelers in the Chesapeake Bay Program to help recalibrate the Chesapeake Bay Watershed Model.

For more information, contact Dr. Robert Hill

Last updated: 02/7/2008