Using the Chesapeake Bay as a case study, Agriculture and Phosphorus Management discusses the impact and management of phosphorus in watersheds. Although urban and other sources contribute phosphorus to the Bay, the papers presented focus on how its role in agriculture impacts water quality. They review the new guidelines and legislation slated for implementation by 2002 directed towards sustainable nutrient management and strategies for implementing them. Phosphorus, an essential element for plant and animal growth, has long been recognized as necessary to eliminate deficiencies and to maintain profitable crop and livestock production. It can increase the biological productivity of surface waters by accelerating eutrophication. Human activities accelerate the rate of eutrophication - principally by increasing the rate at which phosphorus enters the aquatic system. Written by experts from a range of disciplines Agriculture and Phosphorus Management provides a deeper understanding of the diverse, dynamic, and complex factors controlling the impact of agricultural phosphorus management on production and water quality. Each contributor addresses the questions: what do we know, what do we still need to know, where are the major gaps in our knowledge, and how does the information relate to phosphorus management strategies in the Bay Watershed, and other watersheds? As a result this series of papers provides a unique collection of information of regional, national, and international significance and gives prioritized phosphorus management options for not only the Chesapeake Bay Watershed, but for watersheds around the world.