Growth of Native Plants on Mined Materials was not Improved by a Commercial Microbial Inoculant

Abstract

Background and aimsPost-mining landscapes are often lacking in a self-sustaining plant community and in a functional belowground microbial community. Inappropriate management of soil can hinder ecological restoration of mine sites. However, the potential role of microbial inoculants and plant nutrient-acquisition strategies in improving mined substrates and facilitating mine-site restoration remains relatively unexplored. We tested (1) whether a commercially-available microbial inoculant was effective in restoring biological properties of mined substrates, and (2) the effect of plant nutrient-acquisition strategies on improving the chemical properties of mined substrates for the growth of native plants.MethodsWe conducted a six-month glasshouse experiment, growing six native plant species with different nutrient-acquisition strategies and adding a commercial microbial inoculant in three substrates (topsoil, magnetite tailings and a combination of both) from an iron-ore mine site in mid-west Western Australia.ResultsThere was no significant improvement in plant growth by adding a commercially-sourced microbial inoculant. Soil microbial biomass carbon and nitrogen increased significantly after plant growth (main effect of species * inoculation interaction). The non-mycorrhizal disturbance-specialist plant species Maireana georgei was effective in improving hostile conditions of the tailings.ConclusionsOur results indicate that re-vegetating stockpiled topsoil using local keystone species is a desirable practice that can improve soil biological properties and benefit mine-site restoration. Commercially-available agricultural-based microbial inoculants may not be compatible for mine-site restoration using native plants, but future research using indigenous soil microbes is warranted. We recommend selecting native plant species with different nutrient-acquisition strategies and complementary traits (e.g., N-fixing and P-mobilising) when restoring mined substrates.

A Commercial Arbuscular Mycorrhizal Inoculum Alleviated the Effects of Acid Water on Lupinus angustifolius Grown in a Sterilized Mining Dump

“…It is advisable to first investigate the effectiveness of commercial microbial inoculum at a small scale before field application in order to reduce the risks of failure and the associated costs [ 63 ]. The field application of commercial inoculum may not always have desired effects, as demonstrated recently in a mining area [ 64 ].…”

Editorial: Plant-soil-microbe interactions and drivers in ecosystem development and ecological restoration

“…Recognition of these multiple, complex, and interwoven obstacles has led to significantly greater consideration of the role of substrate and edaphic factors in ERR (Nolan et al, 2021); this has reached the point of calls for projects to consider 'engineering' substrates that are suitable for desired biota following significant disturbance to substrates from activities such as mining (Huang et al, 2012;Kumaresan et al, 2017), or to artificially inoculate soils with commercial microbial blends (Farrell et al, 2020;Valliere et al, 2020;Contos et al, 2021), despite limited and inconsistent experimental evidence for the efficacy and risks associated with these techniques (Lance et al, 2019;Wong et al, 2022;Zhong et al, 2023).…”