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 soils. Maximization of the contribution of these micro-organisms can give important benefits for plant production. In some cases, optimization of the infectivity of the target organisms will be achieved most effectively through changing soil management stratregies. In soils where the infective organisms are absent, or where the indigenous isolates are not effective, inoculation with selected isolates may be appropriate. Adoption of inoculation technology depends on a well defined benefit and a reliable source of high quality inoculum at a cost which is appropriate 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 production. Inoculation with rhizobia in legume production meets these criteria 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.