This article continues a series of articles in the 2001 ICM newsletter that provides information to help producers understand phosphorus (P) management and the complex economic and environmental issues involved in P management. This article discusses aspects of P management relevant to watersheds. Every year, producers make decisions about how to manage their operations. Increased production costs can lower profit margins. Profitable farming operations are a delicate balancing act. Decisions about equipment and seed selection, land acquisition and pest management, tillage practices, fertility, and nutrient management are all interrelated production decisions. Now, add a new concept--the environmental issues related to P management on a watershed scale.