Submitted to: Extension Publications
Publication Type: Experiment Station
Publication Acceptance Date: 10/6/2003
Publication Date: 11/20/2003
Citation: Weld, J.L., Beegle, D., Gburek, W.J., Kleinman, P.J., Sharpley, A.N. 2003. The pennsylvania phosphorus index: version 1. Extension Publications.CAT US 180 5M3/03PS 4591. Interpretive Summary:
Technical Abstract: There has been increased attention focused on phosphorus (P) management because of water quality concerns resulting from eutrophication. In fresh water systems, elevated P inputs can lead to accelerated eutrophication and degraded water quality. Despite water quality concerns, adequate levels of soil P must be maintained to promote optimal crop production. Therefore, management options for P must be flexible addressing agronomic concerns while providing water quality protection. The P index is a field evaluation tool that was developed to identify areas that have a high vulnerability or risk of P loss to surface water bodies. This tool combines indicators of P sources and of P transport. The P source indicators used in the Pennsylvania P Index are: Mehlich -3 soil test P, fertilizer application rate and method, and manure application rate, method and P availability. The transport indicators used are: erosion, runoff potential, sub-surface drainage, distance to a water body, and an evaluation of management practices that impact how P is potentially lost from a field. The approach to using the P Index is to develop a nitrogen based nutrient management plan and then evaluate this plan using the P Index. Included in this fact sheet is a brief description of each P Index factor, the information needed for each factor's determination, and a P Index worksheet that can be used to determine the P Index value for multiple fields. Currently, USDA-NRCS in Pennsylvania requires P-based plans developed using the P Index described in this fact sheet. This requirement is a part of the Practice Standard 590 - Nutrient Management and impacts agricultural operators receiving technical or financial assistance for manure related issues.