Poultry manure is high in total P and is often land applied at rates above crop P removal. Such applications and concentrated areas of poultry production have increased soil P levels, which raise environmental concerns. Previous studies have evaluated modifying poultry diet to reduce P excretion. A broiler-breeder diet study examined a standard and a reduced available P rate via non-phytate P (NPP) ration alone and a reduced NPP ration amended with phytase. The four resulting manures were collected and pelletized for soil mineralization and crop response studies. This study examines the P mineralization rate of the four manures at 30 and 60 mg of total P/kg of dry soil in two low P soils.