Despite concerns with expected production, the phosphate fertilizer recommendations for Pernambuco do not take into account influence of the buffer capacity of soil on P availability. Therefore, this work had as objective to evaluate extraction methods to estimate P availability considering content and quality of clay fraction as well mineralogical, chemical and physical soil characteristics. The experiments were carried under field conditions at 'Zona da Mata' of sugarcane cropping area of the State. Five soils were used: Argisol Yellow distrocoeso (PAdx); Latosol Yellow distrophic (LAD); Argisol Yellow distrofic (PAd); Gleisol haplic eutrophic (GXVe); and Espodosol carbic duric (ESKo). The treatments consisted of seven doses of P, determined in function of the P maximum capacity of adsorption (PMCA). The experimental design was a completely randomized treatment block, with four replications. In soil samples collected after treatment application, P was determined by Mehlich-1, Mehlich-3, Bray-1 and ion-exchange resin extractors. Ion-exchange resin did not present correlation with any physical or chemical characteristics of the soils, having extracted P indistinctly, and independent of the soil. However, Mehlich-1 was highly sensible to buffer capacity of P in soil.
extractors of P; buffer capacity of P; P adsorption
