Abstract: To clarify the remediation effects of four amendments (bacteria-based organic manure, organic manure, inorganic fertilizer and bacterial agent) separately combined with Eucalyptus camaldulensis planting on Cd and Pb tailings, we examined physicochemical properties and the proportions of different forms of Cd and Pb in the tailings. Fungal community structure and functional groups were analyzed based on Illumina high-throughput sequencing technology and FUNGuild platform. The dominant environmental factors regulating fungal community structure were analyzed. The results showed that organic manure and bacteria-based organic manure combined with E. camaldulensis significantly increased pH, cation exchange capacity and the proportion of residual Pb while significantly decreased the proportion of reducible Pb. The high-throughput sequencing results showed that the four amendments significantly changed fungal community structure, increased the relative abundance of Agaricomycetes and reduced that of Sordariomycetes in tailings when combining with E. camaldulensis. Functional group analysis results showed that, when combining with E. camaldulensis, organic manure and bacteria-based organic manure increased the relative abundance of soil saprotroph and reduced that of plant pathogen. By contrast, inorganic fertilizer and bacterial agent reduced the relative abundance of soil saprotroph and increased that of plant pathogen. The results of correlation analysis and Mantel test showed that cation exchange capacity, pH, and the proportion of different forms Pb were the key factors affecting fungal community structure. Our results suggest that organic manure and bacteria-based organic manure combining with E. camaldulensis can increase pH and cation exchange capacity, reduce the biological toxicity of Pb in tailings, change the fungal community structure, increase the proportion of soil saprotroph, and reduce plant pathogens. These two amendments are ecologically safe methods for the remediation of Cd and Pb tailings.

Key words: tailings matrix property, fungal community structure, fungal functional group