Phosphate Sorption in Oxisols in Paraíba State, Brazil, Classified as Solution Equilibrium Phosphorus

Aiming to evaluate the phosphorus adsorption in Oxisols with phosphorus remaining classified using the Langmuir isotherm, a study was developed in the laboratory at Federal University of Campina Grande, PB, with samples of the surface layer (0-20 cm) of three Oxisols of the State of Paraíba, differentiating among these the classification of the remaining P-values. The phosphorus levels for adjusting the isotherm were defined based on the remaining P-values. To assess the maximum P adsorption capacity data from P adsorbed and equilibrium concentrations of the solutions were adjusted Langmuir isotherm. This isotherm model could satisfactorily describe the adsorption of phosphorus in soils. The Oxisol sample with high P-rem was the highest value of maximum P adsorption capacity. The maximum P adsorption capacity was correlated with CEC and Ki for the samples classified as P-rem medium and high, respectively.