Concerns about water quality degradation resulting from land appliation of manures and biosolids have elicited a wide array of national and state regulations. The regulations focus on P as the limiting nutrient to eutrophication of most freshwater supplies and threaten to severly impact biosolids recycling. Critical data about biosolids-P phytoavailability and run-off potential, especially field data, needed to validate the regulations are scarce. The goal of this reseach was to supply such data. Conventionally treated biosolids exhibit both less agronomic and environmental impact, such as co-application with water treatment residuals (WTF).