An economist might define the value of improving phosphorus (P) efficiency in agricultural systems as whatever the market place is willing to pay for practices or products that are perceived to deliver improved efficiency. In a more analytical sense, the value depends on definition and the objectives driving P management. Both definition and objectives vary markedly depending on the perspective of the individual or sector. From a crop producer's perspective, objectives of P use usually include optimum nourishment of the current crop for yield and quality, minimization of nutrient losses from the field, and making a positive contribution to system sustainability (future crops). If livestock are included in the operation, an additional objective might involve “efficient” utilization or disposal of P-containing wastes from the livestock enterprise. Still other objectives would be considered if you are a company owning a phosphate mine or the government official responsible for agricultural policy in a developing country. Seldom, if ever, is improving P recovery efficiency the sole objective in on-farm P management. That can always be easily improved by simply applying a sub-optimal P rate at a sub-optimal soil test level. Conceptually, the value of P products and management practices is tied to the contribution they make to efficiently accomplishing all the objectives of P use.