Nitrogen and Phosphorus are nutrients that often limit plant growth in terrestrial ecosystems. Plant available forms of these nutrients present in soil solution include NO₃^- and PO₄^3-, whose mobility is often governed by soil mineralogy. In soils of volcanic influence, PO₄^3- is one of the most strongly sorbed inorganic anions, while NO₃^-, often assumed to have no interaction with the mineral surface, is regarded as the most mobile. The objectives of this study are to characterize the mineralogical and electrochemical characteristics for the subsurface horizons of three forest soils under intensive management in western WA and OR, and relate these properties to the sorption of a lyotropic series of oxyanions (PO₄^3-, SO₄^2- and NO₃^-). Quantification of noncrystalline Fe- and Al-oxides and estimation of allophane and imogolite contents were performed via selective dissolution techniques. The point of zero net charge (PZNC) was determined for each horizon through the simultaneous determination of cation exchange capacity (CEC) and anion exchange capacity (AEC) across a range of pH values. Batch equilibration techniques were utilized to create independent PO₄^3-, SO₄^2- and NO₃^- sorption isotherms for each horizon. Our data suggests an increase in sorption that correlates with both the proportion of oxides present in the subsoil and the charge of the anion. Further understanding of the relationship between soil mineralogy and the mobility of anionic forms of essential plant nutrients will allow for the management of these soils to maximize nutrient retention. Additionally, the demonstrated relationships between anion sorption and the mineralogy of the forest soils of the Pacific Northwest suggests that these systems may have an increased ability to retain dissolved organic species and allow for C and N sequestration through similar mechanisms.