Accounting for the risks of phosphorus losses through tile drains in a phosphorus index

J Environ Qual. Nov-Dec 2012;41(6):1720-9. doi: 10.2134/jeq2012.0238.


Tile drainage systems have been identified as a significant conduit for phosphorus (P) losses to surface water, but P indices do not currently account for this transport pathway in a meaningful way. Several P indices mention tile drains, but most account for either the reduction in surface runoff or the enhanced transport through tiles rather than both simultaneously. A summary of the current state of how tile drains are accounted for within P indices is provided, and the challenges in predicting the risk of P losses through tile drains that are relative to actual losses are discussed. A framework for a component P Index is described, along with a proposal to incorporate predictions of losses through tile drains as a component within this framework. Options for calibrating and testing this component are discussed.

MeSH terms

  • Agriculture*
  • Conservation of Natural Resources
  • Environmental Monitoring / methods*
  • Models, Theoretical
  • Phosphorus / chemistry*
  • Risk Factors
  • Water Movements
  • Water Pollutants, Chemical / chemistry*


  • Water Pollutants, Chemical
  • Phosphorus