Research has shown that measured water-soluble phosphorus (WSP) from poultry litter might have been less than that released in the field. The effects of acidified extractions on soluble P (SP) concentrations were studied, and a buffer was selected to measure SP at pH 6.0, which is a target value for soil management in Georgia. Soluble P concentrations were extracted from poultry wastes at three pHs: 1) at natural pH, using deionized water (DI(w)); 2) after titrating DI(w) suspensions with 0.5N hydrochloric acid (HCl) to pH end-points 3.0, 4.0, and 6.0; and 3) at pH 6.0 with buffers of sodium (Na) acetate, potassium hydrogen phthalate (KHP), 2-(N-morpholino) ethanesulphonic acid (MES), Na cacodylate, imidazole, N-(2-acetamido)-2-aminoethansulphonic acid (ACES), N-(carbamoyl-methyl) iminodiacetic acid (ADA), bis-(2-hydroxyethyl) imino-tris-(hydroxymethyl) methane (Bistris), and 1,4 piperazine-bis-(ethane sulphonic acid) (PIPES). Total SP increased 60% to 140% in suspensions acidified with HCl to pH 6.0 compared to suspensions at pH> or =8. Dissolved unreactive P responded more (2x to 30x) than molybdate reactive P (20-100%). Buffers extracted more soluble minerals than suspensions acidified with HCl, probably because of their complexation ability. The most effective buffer was MES, because its effects seemed mainly due to acidification.