Aluminium dynamics in experimental acidified soils from a humid-temperate region of South Europe

The processes of Al mobilization in soils from NW Spain subjected to an intense acidification were studied. The experiment consisted of the addition of a solution of H2SO4, pH 2.7 to five soils developed from different parent materials and with contrasting properties.In the soils from schist, granulite and serpentinite the treatment led to moderate Al release. In the most acidic soils, those developed from shale and granite, the addition of acid provoked a high degree of mobilization of Al to the soil solution, where Al3+ was found in high concentrations. The analysis of solid fraction and mineral stability calculations revealed that in mineral horizons mobilized Al originated in the inorganic non-crystalline material, whereas in the organic horizons, organic matter constituted the major source of Al.