Determination of inorganic phosphorus (P) species in recently acidified soils of the Columbia Basin (CB) is vital in understanding which available P extraction methods are most appropriate so that fertilizer recommendations can be made accurately.  The objective of this work was to determine dominant P species in recently acidified soils of the CB using both a traditional chemical fractionation schemes and ³¹P NMR spectroscopy.  Several soil samples from the CB ranging in pH (5.2-8.4) together with native calcareous and acidic soils were analyzed.  Chemical fractionation to determine soluble, aluminum (Al), iron (Fe), reductant soluble (RSP), and calcium (Ca) P showed that for the CB soils contained more than 60% of inorganic P as Ca-P.  Significant differences in other fractions were most pronounced in the Fe-P form.  As soil pH decreased the amount of Fe-P extracted increased suggesting a possible transition in soil P chemistry from high to low pH.  Solid state ³¹P NMR spectroscopy was limited by the low soil P content and interference from paramagnetic ions.  No definitive determination of inorganic soil P species could be made.  Despite these limitations, some generalized inferences can be made using the spinning side band (SSB) patterns.  Continued use of the traditional sodium bicarbonate (NaHCO₃) extractable P (Olsen phosphorus, OP) method for making fertility recommendations appears to be the best option for determining plant available P for recently acidified CB soils.