Paddy soils and vegetable soils (pH 5.10-6.95,organic matter 1.21-2.95 % and total phosphorus (P) 0.021-0.067%) in granite area of South China were used in pot experiments applied phosphatic fertilizer,and the "A" values for available phos-phorus according to Fried were determined.The soil samples were fractionated for their soil inorganic P-fractions by the procedure of Chang and Jackson.Equilibrium phosogate potentials (1/2pCa+pH₂PO₄),aluminum phosphate potentials (1/3pAl+pH₂PO₄),manganese phosphate potentials (1/2pMn+pH₂PO₄) and RTlna_H2PO4^- were determined according to White and Beckett's method.