Maximum phosphorus adsorption capacity (Pmax) is a useful tool for characterizing the phosphorus (P) sorption of soils, and the Langmuir model, which allows this estimate, has widespread use. However, estimated values of Pmax and the binding energy constant (k) may be quite different when fitted to non-linear or linearized Langmuir models, or models with single or multiple regions. The objective of this study was to compare the effect of using different methods to fit the Langmuir model to the estimation […]

Iron oxihydroxides form strong chemical bonds with phosphate anions, reducing P availability to plants. The objective of this study, conducted in 1994/95, was to quantify forms of iron oxides in soils from Uruguay, and to study their relationships with phosphorus sorption. Iron oxides extracted with dithionite-citrate-bicarbonate (Fed) from ten soil samples (0-15 cm depth) ranged from 1598 to 8.592 mg kg-1 and were related with their parent material. Poorly ordered Fe-oxihydroxides, extracted by 0.2 mol L-1 ammonium oxalate at pH […]