Idaho manuring rates are constrained by a phosphorus (P) based NRCS 590 Standard. The potential for increased P removal with a winter cereal/corn silage double crop forage system was evaluated in a three year study at the Parma R & E Center in a Greenleaf-Owyhee silt loam. The study involved three winter (barley, wheat, and triticale) and two spring (wheat and triticale) cereals all fall planted at three seeding rates (112, 168, or 224 kg/ha), harvested at the boot stage, and followed with silage corn. Seeding rates of 158 kg/ha were often necessary in winter genotypes for maximizing winter forage biomass and P removal but did not affect forage quality. Winter triticale was the most productive winter forage producing 19.7 Mg/ha of dry mass and removing 59 kg P/ha over the three years. Total P removal with double cropping exceeded P removal with corn alone by at most 42% or 56 kg P per hectare over the three year period (189 vs 133 kg P per hectare). Winter cereal P concentration and P content declined with each successive year of double cropping. Although they have somewhat less potential for dry matter production and P removal, winter and spring wheat were consistently higher in NIR estimated protein, digestibility, and feed value than other fall planted cereals. Double cropping winter forages and corn can increase animal waste loading capacity or hasten soil test P decline in soils enriched with excessive P.