不同类型调理剂对镉污染土壤修复效果和微生物群落的影响

Effects of the different types of conditioners on remediation and microbial community in Cd-contaminated soil

  • 摘要: 【目的】研究土壤调理剂对镉(Cd)污染农田修复效果和微生物群落组成的影响,为应用不同土壤活性组分调理剂原位修复和治理Cd污染农田土壤提供科学依据。【方法】在粤东Cd污染农田开展田间试验,设空白对照,研究不同土壤活性组分调理剂(矿物型、有机型和微生物型)对土壤基本理化性质、Cd有效性和微生物群落结构的影响。【结果】施用土壤调理剂可显著提高土壤pH(0.11~0.24)(P<0.05,下同),增加有机碳含量(21%~47%),降低土壤有效态Cd含量(13%~48%)和糙米Cd含量(26%~42%),其中矿物型和微生物型调理剂对糙米Cd含量的降幅最大。总体上施用调理剂可改善土壤微域环境,高通量测序结果表明,添加调理剂可维持污染土壤中正常微生物群落的多样性和丰富度,显著改变土壤细菌群落的组成和结构,其中脱硫菌门(Desulfobacterota)和拟杆菌门(Bacteroidota)的相对丰度降低。矿物型和有机型调理剂提高土壤中放线菌门(Actinobacteriota)和芽单胞菌门(Gemmatimonadota)的相对丰度,而微生物型调理剂提高酸杆菌门(Acidobacteriota)的相对丰度。同时,矿物型调理剂显著增加真菌的担子菌门(Basidiomycota)的相对丰度,降低子囊菌门(Ascomycota)的相对丰度;而有机型调理剂显著提高被子菌门(Mortierellomycota)的相对丰度,降低罗兹菌门(Rozellomycota)的相对丰度;微生物型调理剂显著增加子囊菌门的相对丰度,降低罗兹菌门的相对丰度。可见,微生物型调理剂可显著提高细菌和真菌中优势种群的水平。糙米Cd含量与微生物群落的相关分析结果显示,糙米Cd含量与细菌群落的变形菌门(Proteobacteria)、脱硫菌门和拟杆菌门呈显著正相关。此外,冗余分析和蒙特卡洛检验分析表明,土壤全磷含量是影响细菌和真菌群落结构的重要环境因子。【结论】从降低土壤有效态Cd和糙米Cd含量及对土壤微生物结构的影响方面考虑,微生物型土壤调理剂修复效果最佳,降低水稻对Cd吸收的同时改善土壤菌群结构。

     

    Abstract: 【Objective】To explore the effects of soil conditioner on the remediation and microbial community composition of cadmium(Cd) -contaminated soil, so as to provide a scientific basis for in-situ remediation and management of Cd-contaminated farmland soils using conditioners with different soil active components.【Method】Field experiments were carried out in Cd-polluted farmland in eastern Guangdong, and blank controls were set to study the effects of different soil active component modifiers(mineral type, organic type and microbial type) on soil basic physical and chemical properties, Cd availability and microbial community structure.【Result】The results showed that the application of soil conditioner significantly increased soil pH(0.11-0.24) (P<0.05, the same below), increased organic carbon content(21%-47%), decreased soil available Cd (13%-48%) and brown rice Cd content (26%-42%). Mineral and microbial conditioners led to the largest decrease of Cd content in brown rice. In general, the application of conditioner improved the soil micro domain environment. The results of high-throughput sequencing showed that adding conditioner could maintain the diversity and richness of normal microbial community in polluted soil and significantly change the composition and soil microbial community structure, in which the relative abundance of Desulfobacterota and Bacteroidota decreased. Mineral and organic conditioners increased the relative abundance of Actinobacteriota and Gemmatimonadota in soil, while microbial conditioners increased that of Acidobacteriota. Further, for fungal communities, mineral conditioner significantly increased the relative abundance of Basidiomycota and decreased that of Ascomycota. Organic conditioner significantly increased the relative abundance of Mortierellomycota and decreased that of Rozellomycota. Microbial conditioner significantly increased the relative abundance of Ascomycota and decreased that of Rozellomycota. Obviously, the microbial conditioner could significantly improve the level of dominant populations of bacteria and fungi. Correlation analysis showed that brown rice Cd content and microbial community were significantly positively correlated with Proteobacteria, Desulfobacterota and Bacteroidota. In addition, redundancy analysis and Monte Carlo test showed that the total phosphorus content in soil was an important environmental factor affecting the community structure of soil bacteria and fungi.【Conclusion】In terms of reducing the content of available Cd in soil and Cd in brown rice and its impact on soil microbial structure, microbial soil conditioner has the best remediation effect, which can reduce the Cd in brown rice and improve the structure of soil flora.

     

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