Concentration of exchangeable and soluble aluminium in acid forest soils in Greece

Abstract

The concentration of exchangeable and soluble Al in acid forest soils in Greece as developed under a range of conditions was studied. The concentration of exchangeble Al ranged from 2 to 1000 ppm (0.02–11.1 soil), increased with elevation, and it was highest in the top mineral horizon of soils derived from schists under beech. Concentration levels and trends of exchangeable A1 were controlled mainly by soil pH. The concentration of soluble A1 and the value of the molar Ca:Al ratio in saturation extracts of these soils ranged from 0.1 to 2.34 ppm and from 0.4 to 74, respectively. The concentration of soluble A1 was higher in the top mineral soil horizon but the reverse was found for the molar Ca:Al ratio. Base-saturation levels of the humus layer ranged from 10 to 60% and decreased with increasing elevation. These findings are examined in the light of the dynamics of forest soils and the special mode of nutrition of forest trees, in an effort to explain the absence of visible adverse effects of Al on the health of forest trees in Greece.