The Phosphorus Index (P-Index) Risk Assessment Tool was developed cooperatively with OWSI, Colorado State University and the USDA – Natural Resource Conservation Service (NRCS). It is a tool for planners, producers, and consultants to assess the qualitative risk of Phosphorus loss off-site in cropland areas.
The P-Index tool will not quantify the amount of phosphorus transported, but instead, ranks the relative potential of phosphorus transport off-site. This helps determine if it is appropriate to apply nutrients (i.e. fertilizer, manure, biosoilds, etc.) to a particular field for crop requirements or if the risk is too great.