BIOREMEDIATION OF AGRICULTURAL AND FORESTRY SOILS WITH SYMBIOTIC MICROORGANISMS

Symbiotic micro-organisms are important in alleviating the limitations of nitrogen and phosphorus deficiency on plant growth in Australian s oils. Maximization of the contribution of these micro-organisms can gi ve important benefits for plant production. In some cases, optimizatio n of the infectivity of the target organisms will be achieved most eff ectively through changing soil management stratregies. In soils where the infective organisms are absent, or where the indigenous isolates a re not effective, inoculation with selected isolates may be appropriat e. Adoption of inoculation technology depends on a well defined benefi t and a reliable source of high quality inoculum at a cost which is ap propriate for the overall cost structure and returns of the industry. Further, inoculation should not require additional complex technology or machinery and should fit easily into existing processes of producti on. Inoculation with rhizobia in legume production meets these criteri a and consequently is widely used. By contrast, inoculation with VA or ectomycorrhizal fungi still only occurs on a small scale, in part due to practical difficulties of inoculum production but also due to the limited number of situations where the benefits of inoculation can be clearly demonstrated.