Phosphorus (P) is an essential nutrient for terrestrial and aquatic plants. We recognize the beneficial effects of P on the growth and yields of beneficial crops. There is increasing concern and attention being given to phosphorus losses from agricultural soils. Substantial amounts of P entering surface waters (lakes, other surface impoundments and streams) contribute to accelerated eutrophication of lakes and reservoirs. Eutrophication is a process by which a water body becomes rich in dissolved nutrients and, often, seasonably deficient in oxygen. Eutrophication due to excessive algal and other plant growth and their ultimate decomposition, which consumes oxygen, limits the use of surface waters for aesthetics, fisheries, recreation, industry and drinking.