Fisher, NB 2012, 'Commercial microbial inocula – do they work?', in AB Fourie & M Tibbett (eds), Mine Closure 2012: Proceedings of the Seventh International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 449-457, https://doi.org/10.36487/ACG_rep/1208_39_Fisher (https://papers.acg.uwa.edu.au/p/1208_39_Fisher/) Abstract: The important role that soil organisms play in nutrient cycling and plant health has long been recognised in the scientific literature, as well as in the agricultural and mining industries. The market for commercially available inocula of important nutrient cycling microbes aimed specifically at Australian native flora is not developed as agriculture with far fewer products. Here the author presents the results of a trial utilising commercially available inocula marketed as capable of inoculating native flora. Eleven species of plants commonly found in the Box-Gum Woodlands of central western New South Wales and parts of Queensland were grown under nursery conditions and harvested after 150 days. Faboideae species trialled were Acacia spectabilis (A. Cunn. ex Benth.), A. doratoxylon (A. Cunn.), Daviesia ulicifolia (Andrews), Pultenaea cinerascens (Maiden and Betche) and Hardenbergia violacea (Schneev.ex Stearn). Treatments included rhizobial, mycorrhizal + bacteria, and combined inoculation, with commercial nursery soil without inoculation as the control. Preliminary results showed considerable variation between the species. A. spectabilis grew well regardless of treatment and formed root nodules with rhizobia (presumably) resident within the control nursery soil. H. violacea also nodulated when grown in the control treatment, but showed improved growth with both the rhizobial inoculation treatment with the combined treatment. A. doratoxylon, D. ulicifolia and P. cineracsens all showed increased survival and growth with each treatment; i.e. no survival in the control, low survival and poor growth after inoculation with mycorrhizal fungi + bacteria, increased growth again with rhizobial inoculation and markedly improved growth with combined inoculation. In addition to D. viscosa, five eucalypt species were trialled; E. albens, E. conica, E. dawsonii, E. melliodora and E. moluccana. These plants were the subject of two treatments only, the control (as above) and inoculation with mycorrhizal fungi + bacteria. Inoculation actually suppressed growth in the majority of species a phenomenon often recorded in the literature. Preliminary conclusions show that commercially available inocula can infect target plant species and may provide a useful addition to the tools available for rehabilitation in the absence of available topsoil with a viable microbial population.