The interrelationship between plant species distribution and properties of soils undergoing podzolization in a coastal area of S.W. Australia

Abstract

A study of soil and vegetation characteristics within a small area of coastal heath near The Gap, Albany, Western Australia, showed that significant differences exist in plant species composition between podzol and non-podzol (calcareous) soil environments. Leaf extracts of common plant species from podzol, non-podzol and transitional soil sites were tested for their ability to complex with iron. Only those species on the podzol and transitional soils proved to have this ability. Soil column experiments tested the rates of iron mobilization and results indicate that the podzol vegetation elutant solution, which was found to contain the iron-complexing agent gallic acid, was superior to the non-podzol vegetation elutant solution in the rate at which it mobilized iron. It is suggested that initiation of podzolization is due to the presence of gallic acid in the leaves of certain of the species in the coastal heath association, and that the pattern of podzol distribution can be linked to both plant succession and inherent differences in soil parent material.