Microbial diversity and activity are increased by compost amendment of metal-contaminated soil

Abstract

Unlike organic pollutants, heavy metals cannot be degraded and can constitute a persistent environmental hazard. Here, we investigated the success of different remediation strategies in promoting microbial diversity and function with depth in an acidic soil heavily contaminated with Cu, Pb and Zn. Remediation involved the incorporation of either a high-or a low-quality compost or inorganic fertilizer into the topsoil and monitoring of microbial activity and diversity with soil depth over a 4-month period. While changes in topsoil microbial activity were expected, the possible effects on the subsurface microbial community due to the downward movement of metals, nutrients and/or soluble organic matter have not been examined previously. The results showed that both compost additions, especially the low-quality compost, resulted in significantly increased bacterial and fungal diversity (as assessed by terminal restriction fragment length polymorphism) and activity compared with the inorganic and control treatments in the topsoil. Although phospholipid fatty acid profiling indicated that compost addition had promoted enhanced microbial diversity in the subsoil, no concomitant increase in subsoil microbial activity was observed, suggesting that amelioration of the heavy metals remained localized in the topsoil. We conclude that although composts can successfully immobilize heavy metals and promote ecosystem diversity/function, surface incorporation had little remedial effect below the surface layer over the course of our short-term trial.

RETRACTED ARTICLE: Field evaluation of intensive compost application on Cd fractionation and phytoavailability in a mining-contaminated soil

“…Alvarenga et al (2007) reported that sewage sludge amendment increased soil protease and urease activities, while the application of garden waste compost had no influence on their activities in an acid metal-contaminated soil affected by mining activities. Farrell et al (2010) demonstrated that soil microbial biomass carbon (MBC) and basal respiration were improved after incorporation of green waste-derived compost into an acidic soil contaminated with Cu, Pb and Zn at Parys Mountain, Anglesey, North Wales.…”

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The Effect of Re-Planting Trees on Soil Microbial Communities in a Wildfire-Induced Subalpine Grassland

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