Use of Annual Phosphorus Loss Estimator (APLE) model to evaluate a Phosphorus Index

Nicole M. Fiorellino, Joshua M. McGrath, Peter A. Vadas, Carl H. Bolster, Frank J. Coale

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The Phosphorus (P) Index was developed to provide a relative ranking of agricultural fields according to their potential for P loss to surface water. Recent efforts have focused on updating and evaluating P Indices against measured or modeled P loss data to ensure agreement in magnitude and direction. Following a recently published method, we modified the Maryland P Site Index (MD-PSI) from a multiplicative to a component index structure and evaluated the MD-PSI outputs against P loss data estimated by the Annual P Loss Estimator (APLE) model, a validated, fieldscale, annual P loss model. We created a theoretical dataset of fields to represent Maryland conditions and scenarios and created an empirical dataset of soil samples and management characteristics from across the state. Through the evaluation process, we modified a number of variables within the MD-PSI and calculated weighting coefficients for each P loss component. We have demonstrated that our methods can be used to modify a P Index and increase correlation between P Index output and modeled P loss data. The methods presented here can be easily applied in other states where there is motivation to update an existing P Index.

Original languageEnglish
Pages (from-to)1380-1387
Number of pages8
JournalJournal of Environmental Quality
Issue number6
StatePublished - Nov 1 2017

Bibliographical note

Publisher Copyright:
© American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. 5585 Guilford Rd., Madison, WI 53711 USA.

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Management, Monitoring, Policy and Law


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