Aluminium fractionation in Galician (NW Spain) forest soils as related to vegetation and parent material

Aluminium extracted by acid oxalate, pyrophosphate, CuCl2 and NH4Cl, as well as concentration and speciation of aluminium in the soil solution, were studied in soils from the province of Lugo (Galicia, Spain). Soils, developed from different parent materials (granodiorite, shale and limestone), differ also in type of vegetation (oak (Quercus robur), pine (Pin us radiata) and eucalypt (Eucalyptus nitens)) and degree of evolution. Soils developed from limestone, highly developed and acid, showed the highest contents of all forms of non-crystalline and organically bound aluminium. The tree species affected significantly the contents of the most labile aluminium forms (exchange and solution aluminium), which were highest in soils developed from limestone and bearing pine vegetation. (C) 2002 Elsevier Science B.V. All rights reserved.