An experiment was carried out to study phosphorus (P) adsorption in ten soil samples from Pernambuco State, Northeastern Brazil. The relationship between physical and chemical soil attributes and P adsorption isotherms were also evaluated. The results showed that maximum phosphorus adsorption capacity (MPAC), remaining P (Rem-P) and the k constant of the Freundlich equation are reliable variables to characterize P adsorption by the soils. Due to its easy determination, Rem-P is the best indicated variable. The parameters of P adsorption MPAC, Rem-P and the k constant of the Freundlich equation showed correlation (p < 0.01) with the chemical attributes potential acidity (H+Al), exchangeable aluminum (Al), exchangeable cation capacity (ECC) and with the physical attributes clay and field capacity (FC). The variables FC, Rem-P, H+Al, Al, ECC and clay, among the chemical and physical attributes evaluated, allowed estimating the MPAC value on the studied soils. The P adsorption energy and the n constant of the Freundlich isotherm were not reliable indicators of the P soil adsorption power.
phosphorus fixation; Langmuir; Freundlich
