Extension Publications

The Phosphorus Index (P Index) is a site-specific, qualitative vulnerability assessment tool. This tool allows a conservation planner to determine the sites that are potentially most vulnerable to off-site movement of phosphorus. The P Index is used to determine where application of manure/organic by-products should be based on either a nitrogen-based budget or a phosphorus-based budget. The P Index is NOT to be used in any area designated as phosphorus limited by legislation (e.g. Everglades, Green Swamp, and Okeechobee Basin) to determine if a nitrogen-based nutrient budget can be used. These areas are to have phosphorus-based nutrient budgets regardless of the nutrient source or soil type. The P Index should, however, be used to implement conservation practices to reduce phosphorus movement in these areas.

The purpose of the P Index is to aid planners and others in the decision-making process involved in designing conservation plans related to land application of animal wastes. The P Index is not intended to be an evaluation tool to determine compliance of water quality standards by any regulatory agency. Any attempt to use the P Index as a regulatory tool would be grossly beyond the intent of the concept and philosophy of the P Index developers. The P Index is a science-based decision making tool that will support conservation planning and component planning of nutrient management. Concerns regarding P management of manure/organic by-product recycling can be effectively communicated to landowners if the P Index is consistently applied.

Phosphorus Index by County