| Abstract: | Soil samples obtained from genetic horizons of an upland and acid sulphate soil of Sierra Leone, were equilibrated with 0.01 M CaCI using a 1:2 soil to solution ratio. Al3+ activity was estimated from total Al measured in the equilibrium extract, by accounting for hydrolysis and the formation of other complex species. The Al3+ activity was pH-dependent, but the Al(OH)3 ion product was I'airly constant throughout the upland soil profile; Al3+ activity was near that expected for equilibrium with kaolinite and quartz. In the acid sulphate soil alunite appeared to control the activity of Al3+. |
