AbstractTropical acid soils adsorb a large portion of phosphorus added to them. In order to study the characteristics of phosphorus adsorption in 10 Nigerian acid soils, 2 g of soil were equilibrated in 0.01M CaCl2 containing various amounts of phosphorus for 48 hours. The phosphorus disappearing from solution was taken as the amount adsorbed. The capacity to adsorb phosphorus varied among the soils, but in general the more strongly weathered soils from the eastern area adsorbed more phosphorus than those from western Nigeria. At low concentrations of phosphorus in the equilibrium solution, the adsorption could be satisfactorily described by Langmuir Isotherm equation. The adsorption was significantly correlated with sesquioxides and the exchangeable forms of Al and Fe as well as the clay content and pH. The citrate‐dithionite and the oxalate extractable oxides were of equal significance in the phosphorus adsorption, but the role of Al was more important than that of Fe.
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