Comparison of aluminium, basic cations and acidity in the soil of indigenous forests and pine stands in the southern Cape

Abstract

Litter and topsoil were sampled in plantations of Pinus elliottii and Pinus taeda and in adjacent indigenous forest in three different locations in the southern Cape, to study some of the effects on the soil of the establishment of pine plantations in this region. Litter from the forest was less acid and contained less aluminium and more calcium, magnesium and potassium than litter from the plantations. At all three sites, topsoil under pines contained more organic aluminium and lower concentrations of basic cations. The pH was lower and aluminium levels were higher in the soil under pines at one of the sites. This could result in decreased fertility in later rotations. It is suggested that changes in the cycling process of mineral elements and in the decomposition dynamics of litter after the establishment of pine plantations have caused these changes in the soil.