Arbuscular Mycorrhizal Fungi (AMF) and Biosolids Enhance the Growth of a Native Australian Grass on Sulphidic Gold Mine Tailings

We tested the effect of the addition of biosolids combined with a native mycorrhizal inoculum (Arbuscular Mycorrhizal Fungi [AMF]) on growth of a native Australian grass, and on trace element stabilization of sulphidic gold mine tailings. A glasshouse trial was established on four substrates: tailings (T); tailings with a layer of 5 cm topsoil (TS); tailings amended with 100 dry t ha^-1 biosolids (LB), and tailings amended with 500 dry t ha^-1 biosolids (HB). Pots of 1.2 L of capacity were established; some were inoculated with a mixture of Glomus sp. (WUM51-9227), Scutelospora aurigloba (WUM51-53), and Acaulospora levis (WUM46) culture mix, and others were uninoculated controls. Seeds of the native Australian grass, Bothriochloa macra were sown in the pots. Root infection, plant biomass production, nutrients and trace element concentrations in shoots were investigated.Addition of biosolids significantly increased AMF infection of roots compared to unamended substrates. No clear qualitative differences in colonization were detected. Addition of biosolids and AMF together clearly improved the establishment and growth of the native grass. Similar trends in nutritional status were shown for biosolids and inoculation with AMF treatments. Mycorrhizal inoculation increased plant biomass production and the effectiveness of nutrient uptake. The combined use of biosolids and mycorrhizal inoculation could be a reliable method for phytostabilization purposes in polluted substrates.