SOIL HEALTH

Microbial health of topsoil stockpiled at mine sites across Western Australia - Leveraged Project

This study, led by Dr Haylee D’Agui, involves mine sites across Western Australia (from the Pilbara to the South West), encompassing different commodities (iron ore, nickel, bauxite, coal, and mineral sands), and aims to determine the changes that occur in microbial communities (fungi and bacteria) as topsoil is stockpiled.

Background

Topsoil is a valuable resource in post-mining restoration, as it is high in organic matter and nutrients and contains plant propagules and soil microbes (Golos & Dixon, 2014; Jasper, 2007). A variety of factors, including the size and depth of stockpiles, duration of storage, soil type, climate, and method of storage affect the quality and functionality of the topsoil when it is eventually used in restoration (Abdul-Kareem & McRae, 1984; Birnbaum, Bradshaw, Ruthrof, & Fontaine, 2017). Soil functionality needs to be taken into consideration when restoring mine sites, and so it is critical to reinstate a healthy microbial community post-disruption in order to achieve success in restoration programs (Harris, Birch, & Short, 1993; Munoz-Rojas, Erickson, Dixon, & Merritt, 2016). However, soil functionality in restored soils has been found to be non-comparable to that of undisturbed native soils (Munoz-Rojas et al., 2016). To ensure continual improvements in existing rehabilitation practice, scientifically-driven research is needed to understand and manage constraints imposed by inefficient topsoil storage.

Aims and Objectives

The topsoil health study being undertaken by the CMSR aims to determine how the diversity, abundance, and activity of soil microbes contained within topsoil stockpiles is influenced by factors such as storage time, for different regions and commodity types in Western Australia. The outcomes of the study will contribute to the development of science based topsoil management guidelines in order to optimise biodiversity recovery in mining soils for improved restoration outcomes.

Significance

Topsoil is a scarce and valuable resource in mine site restoration that is currently not being used to its full potential due to degradation during storage in stockpiles. Management of topsoil for use post-mining is an integral component in restoration. This study will:

  • Contribute to the development of science based topsoil management guidelines to inform resource companies and restoration practitioners in design and management of effective topsoil storage strategies that maintain topsoil function for improved restoration outcomes.
  • Provide valuable information on the microbiome present within topsoil stockpiles located at mine sites across Western Australia, and how these compare to undisturbed reference communities, revealing the effects that topsoil storage has on the microbiome.
  • Provide valuable baseline information on the microbiome present within native reference sites sampled across Western Australia.

References

Abdul-Kareem, A. W., & McRae, S. G. (1984). The effects on topsoil of long-term storage in stockpiles. Plant and Soil (Vol. 76). Birnbaum, C.,
Bradshaw, L. E., Ruthrof, K. X., & Fontaine, J. B. (2017). Topsoil Stockpiling in Restoration : Impact of Storage Time on Plant Growth and Symbiotic Soil Biota Topsoil Stockpiling in Restoration : Impact of Storage Time on Plant Growth and Symbiotic Soil Biota. Ecological Restoration, 35(September), 237–245. https://doi.org/10.3368/er.35.3.237
Golos, P. J., & Dixon, K. W. (2014). Waterproofing topsoil stockpiles minimizes viability decline in the soil seed bank in an arid environment. Restoration Ecology, 22(4), 495–501. https://doi.org/10.1111/rec.12090
Harris, J. A., Birch, P., & Short, K. C. (1993). The Impact of Storage of Soils during Opencast Mining on the Microbial Community: A Strategist Theory Interpretation. Restoration Ecology. https://doi.org/10.1111/j.1526-100X.1993.tb00014.x
Jasper, D. A. (2007). Beneficial soil microorganisms of the jarrah forest and their recovery in bauxite mine restoration in Southwestern Australia. Restoration Ecology, 15(SUPPL. 4), 74–84. https://doi.org/10.1111/j.1526-100X.2007.00295.x
Munoz-Rojas, M., Erickson, T. E., Dixon, K. W., & Merritt, D. J. (2016). Soil quality indicators to assess functionality of restored soils in degraded semiarid ecosystems. Restoration Ecology, 24(August), S43–S52. https://doi.org/10.1111/rec.12368