In order to determine the characteristics of phosphorus adsorption using the Langmuir and Freundlich isotherms and its relationship with some of the chemical and physical properties of soils, a study was developed at the Embrapa Soil Laboratory with soil samples (0 - 30 cm) from four classes of topsoil: Orthic Chromic Luvisols, Eutrophic Cambisols, Fluvic Neossol and Eutrophic Cambisols Typical. The hyperbolic model of the Langmuir isotherm was fitted by the non-linear regression technique. We performed a correlation analysis between the isotherm parameter values and soil characteristics that reflected the Phosphate Maximum Capacity. The values of remaining phosphorus ranged from 16.28 to 43.73 mg L-1 for the soils. For the Langmuir isotherm, the maximum phosphorus adsorption capacity (MPAC) values ranged from 0.2793 to 0.3954 mg g-1 of soil. The RY soil had the largest amount of adsorbed phosphorus (0.3954 mg g-1), giving this soil a high MPAC.
Key words: Tropical soils, phosphorus, buffering capacity.