Eutrophication, caused by phosphorus enrichment, is not a new environmental problem. The persistence of eutrophication in an era when many point-source phosphorus inputs have been curtailed has turned the focus of attention to agricultural phosphorus. A workshop was held in Ireland in 1995 to discuss factors controlling phosphorus losses to water from agriculture. This book presents the proceedings of the workshop and consists of 18 chapters by the invited speakers and three chapters with the 45 poster papers displayed at the workshop.