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Purpose <p>Although various materials have been utilized as potential amendments to improve the effectiveness of phytostabilization in mine tailings remediation, their differential impacts on the physicochemical properties of tailings, plant growth, and rhizosphere microbial communities remain insufficiently understood. This study aims to comparatively evaluate the remediation efficacy of three amendments in Pb–Zn tailings by examining the alterations of tailings properties, ryegrass (<i>Lolium perenne</i> L.) growth, and rhizosphere microbiome composition.</p> Methods <p>Pb–Zn tailings were subjected to treatment with three different amendments (native topsoil, corn straw, and chicken manure) at application rates of 3% and 5% (w/w), followed by a two-month pot experiment involving the cultivation of ryegrass. The physicochemical properties of the substrate, the aerial biomass of ryegrass, and the microbial community profiles in the rhizosphere were systematically analyzed.</p> Results and discussion <p>The results demonstrated that the application of all amendments significantly improved phosphorus and potassium availability in the tailings and reduced the bioavailability of zinc compared to the unamended control. Specifically, the 5% chicken manure treatment markedly increased the levels of available phosphorus and potassium while exhibiting effective immobilization of heavy metals (except for copper), resulting in an 85.29-fold increase in the aerial biomass of ryegrass. Mechanistically, this treatment enhanced bacterial richness, suppressed oligotrophic microorganisms such as Actinobacteriota, Verrucomicrobiota, and Chloroflexi, and promoted the proliferation of copiotrophic microorganisms (e.g., Firmicutes) as well as metal-resistant taxa including Proteobacteria, Gemmatimonadota, and Myxococota. Redundancy analysis revealed available phosphorus, potassium, and diethylenetriamine-pentaacetic acid-extractable copper and cadium as the key factors shaping the structure of rhizosphere microbial community.</p> Conclusions <p>The application of 5% chicken manure amendment was identified as the most effective approach for concurrently improving edaphic nutrient status, immobilizing metallic contaminants, and promoting a more diverse rhizospheric community in Pb–Zn tailings. These findings offer valuable theoretical and practical insights for the implementation of amendment-assisted <i>in-situ</i> phytoremediation strategies in metal-contaminated tailing environment.</p>

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Remediation efficacy comparison of soil amendments in Pb-Zn tailings: physicochemical properties, ryegrass growth and rhizosphere microbiota

  • 期刊论文

  • 发表日期：

    2026年3月9日

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  • Shimin Liu,
  • Kuangnan Sun,
  • Meng Wang,
  • Jing Xiang,
  • Taowu Ma,
  • Yingru Zhou

摘要

Purpose

Although various materials have been utilized as potential amendments to improve the effectiveness of phytostabilization in mine tailings remediation, their differential impacts on the physicochemical properties of tailings, plant growth, and rhizosphere microbial communities remain insufficiently understood. This study aims to comparatively evaluate the remediation efficacy of three amendments in Pb–Zn tailings by examining the alterations of tailings properties, ryegrass (Lolium perenne L.) growth, and rhizosphere microbiome composition.

Methods

Pb–Zn tailings were subjected to treatment with three different amendments (native topsoil, corn straw, and chicken manure) at application rates of 3% and 5% (w/w), followed by a two-month pot experiment involving the cultivation of ryegrass. The physicochemical properties of the substrate, the aerial biomass of ryegrass, and the microbial community profiles in the rhizosphere were systematically analyzed.

Results and discussion

The results demonstrated that the application of all amendments significantly improved phosphorus and potassium availability in the tailings and reduced the bioavailability of zinc compared to the unamended control. Specifically, the 5% chicken manure treatment markedly increased the levels of available phosphorus and potassium while exhibiting effective immobilization of heavy metals (except for copper), resulting in an 85.29-fold increase in the aerial biomass of ryegrass. Mechanistically, this treatment enhanced bacterial richness, suppressed oligotrophic microorganisms such as Actinobacteriota, Verrucomicrobiota, and Chloroflexi, and promoted the proliferation of copiotrophic microorganisms (e.g., Firmicutes) as well as metal-resistant taxa including Proteobacteria, Gemmatimonadota, and Myxococota. Redundancy analysis revealed available phosphorus, potassium, and diethylenetriamine-pentaacetic acid-extractable copper and cadium as the key factors shaping the structure of rhizosphere microbial community.

Conclusions

The application of 5% chicken manure amendment was identified as the most effective approach for concurrently improving edaphic nutrient status, immobilizing metallic contaminants, and promoting a more diverse rhizospheric community in Pb–Zn tailings. These findings offer valuable theoretical and practical insights for the implementation of amendment-assisted in-situ phytoremediation strategies in metal-contaminated tailing environment.