Fig. 1. Adsorption isotherms for the two soils, (a) Betsele and (b) Flakastugan. The batch sorption experiments were performed in both deionized water (unfilled squares) and 0.1 mol dm^–3 NaCl (crosses). The error bar denotes the maximum confidence interval for the Betsele (n = 3–5) and Flakastugan soil (n = 2). The total amount of sorbed phosphate, q, has been defined as the sum of the native amount of inorganic phosphate (2.9 and 7.2 mmol kg^–1 for the Betsele and Flakastugan soil, respectively) and the sorbed inorganic phosphate.