Edafología. Volumen 7-1. Abril 2000. pág 61-71.
In this study SO 4 2- sorption and acidification processes related to external inputs were investigated in two soils (Typic Fulvudand and Andic Hapludox) developed on an amphibolitic massif. These soils represent the initial and the final stages of the pedogenic processes on this material. Samples were taken from two horizons with very contrasting minerological characteristics: the horizon with andic properties (Ah) of the former soil, and the kandic horizon (Bo) of the latter. Sulfate sorption studies were conducted using K 2 SO 4 solutions (ranging from 0.4 to 3.2 mM) adjusted to different pH values (from 2.0 to 5.5). Sorption was high in the Bo horizon, which was rich in crystalline Fe compounds, even at low SO 4 2- concentrations and high pH values (whithin the pH range studied), while sorption in the Ah horizon, in which Al compounds dominate in the colloidal fraction, was more pH-dependent and increased greatly at low pH values.
Key words: sulfate sorption, soil acidification, andic properties, kandic horizon, parent material.