Bioassay Measurements of Mycorrhizal Inoculum in Soils from Eucalyptus Plantations of Varying Ages in Western Australia

Bioassay measurement was used to estimate the inoculum potential of mycorrhizal fungi in intact soils collected from Eucalyptus plantations of varying ages in Western Australia.The results showed that both ectomy corrhizal (ECM) and vesicular-arbuscular my corrhizal (VAM) fungi existed in soils from most plantation sites according to two bait plants (clover for VAM and Eucalyptus for ECM). The levels of ECM or VAM fungal inoculum were considered to be moderate. Analy sis of roots sampled from plantations suggest that Eucalyptus stands are more associated with VAM fungi compared to ECM fungi that occupied most fine roots in older stands. Information from the bioassay experiment suggests that there may be a need for the introduction of a wider range of inoculum to assist the establishment of new Eucalyptus plantations in this region. Further work is required on below-ground ECM fungal diversity in these plantations.