Final Report submitted to the Manitoba Livetock and Manure Management Initiative. Continuous application of manure P above crop removal results in a buildup of soil phosphorus (P), which increases the risk of P runoff loss from agricultural land, leading to environmental problems such as eutrophication of surface waters. There is little or no information about the forms of manure P that are correlated with risk of P loss after manure interacts with soil, especially for prairie soils. The objectives of this study were to quantify and compare P losses from liquid swine- and solid cattle- manure treated soils after incubating for 6 weeks, and to relate P losses to manure P forms and soil test P after incubation.