ABSTRACT

Evaluating the potential risk of phosphorus (P) loss from crop fields to surface-and groundwater resources is an important component of the nutrient management planning process. Nearly all states have developed a P index (PI) or other state-specific P risk assessment tool for this purpose. Though most PIs were originally implemented as paper worksheets or computer spreadsheets, in practice nearly all planners will use PI tools implemented via computer software to speed up the planning process.