Applications of sulfate and carbonate salts have been shown to improve the solubility of phosphorus (P) in model calcareous soils. It is unclear how these treatments will influence P solubility in real soils. The objective of this study was to determine the effect of sulfate or carbonate salts on P solubility in selected Manitoba soils. We hypothesized that the application of carbonate or sulfate salts in a fertilizer band could enhance the solubility of P in Manitoba soils. Different salt mixtures were prepared by mixing either monopotassium phosphate (MPP) or monoammonium phosphate (MAP) with K₂SO₄, (NH₄)₂SO₄, MgSO₄, or (NH₄)₂CO₃. After the 2 wk of incubation of salt-treated soils, both P sources decreased soil pH significantly. The addition of salts did not significantly affect pH in most of the soils. There was a significant treatment effect (P<0.0001), a significant soil effect (P<0.0001), and a significant soil by treatment interaction (P<0.0001) on water-extractable P. Coapplication of either sulfates or (NH₄)₂CO₃ salt increased soluble P in some soils by 6%–44% or 11%–14%, respectively. Application of carbonate or sulfate salts increased P solubility only in soils with a smaller ratio of HCl-extractable Ca to ammonium acetate-extractable Ca.