ARS | Publication request: Comparing the Kentucky phosphorus index with P loss calculated with a process-based model

Submitted to: Kentucky Water Resources Research Institute Symposium
Publication Type: Proceedings
Publication Acceptance Date: February 10, 2011
Publication Date: June 28, 2011
Citation: Bolster, C.H. 2011. Comparing the Kentucky phosphorus index with P loss calculated with a process-based model. Kentucky Water Resources Research Institute Symposium. 49-51. www.uky.edu/WaterResources/2011Proceedings.pdf

Technical Abstract: Eutrophication from excess phosphorus (P) loading is widespread among U.S. water bodies with a substantial portion of the P originating from agricultural fields. To reduce the impact agriculture has on water quality, USDA-NRCS includes P-based planning strategies in their 590 Standard to restrict P application to fields where the risk of P loss is high. In the 590 Standard, the most common strategy employed to rate a field’s vulnerability to P loss is the P index. The P index is an assessment tool developed to identify fields which are most vulnerable to P loss by accounting for the major source and transport factors controlling P movement in the environment. USDA-NRCS is currently revising the 590 Standard and may require states to test the accuracy of their P index. When measured edge-of-field P loss data are scarce, as is the case in Kentucky, a P index can be tested against P-loss data generated from a validated process-based P transport model. With this in mind, the objective of this study was to compare KY P index values with simulated P loss data obtained from a validated P-loss model to identify areas where the index may need revising.