Stability of soil organic matter in Eucalyptus regnans forests and Pinus radiata plantations in south eastern Australia

Abstract

A number of indices of soil carbon (total C, Walkley-Black organic C, water-soluble C, K2SO4-extractable C and microbial biomass C) were measured to assess the stability of soil carbon in two managed forest types in Australia. Carbon concentrations generally decreased, and soil density increased, with soil depth to 50 cm, and were an order of magnitude greater in clay loam soils under native forests of Eucalyptus regnans than in sandy soils under plantations of Pinus radiata. In E. regnans stands, concentrations of soil carbon increased with stand age, but due to a corresponding decrease in soil density there was no trend in carbon content with stand age, with the exception of microbial biom..