Agricultural phosphorus, water quality, and poultry production: are they compatible?

With the concentration of poultry production and increase in operation size in several regions of the U.S., more manure is applied to agricultural land. This application of manure has resulted in more P being added than crops require, an accumulation in soil P, and increased potential for P loss in surface runoff. This situation has been exacerbated by manure management being N-based. Increased outputs of P to fresh waters can accelerate eutrophication, which impairs water use and can lead to fish kills and toxic algal blooms. As a result, information is needed on the effect of poultry production on the fate of P in agricultural systems so that compatible production and water quality goals can be met. Overall, these goals will be met by focusing on ways to increase P use-efficiency by attempting to balance inputs of P in feed and fertilizer into a watershed with output in crop and livestock. This will involve refining feed rations, using feed additives to increase P absorption by the animal, moving manure from surplus to deficit areas, finding alternative uses for manure, and targeting conservation practices, such as reduced tillage, buffer strips, and cover crops, to critical areas of P export from a watershed. These critical areas are where high P soils coincide with parts of the landscape where surface runoff and erosion potential is high. Development of management systems that address both production and environmental concerns must consider the socioeconomic and political impacts of any management changes on both rural and urban communities, and of the mechanisms by which change can be achieved in a diverse and dispersed community of land users.