College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China.
School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
Sci Total Environ. 2022 Sep 15;839:156202. doi: 10.1016/j.scitotenv.2022.156202. Epub 2022 May 24.
The combination of biochar and specific bacteria has been widely applied to remediate Cadmium-contaminated soil. But little is known about how such composites affect the dynamic distribution of metal fractions. This process is accompanied by the alternations of soil properties and microbial community structures. Composite of rice straw biochar and Bacillus cereus RC-1 were applied to investigate its impacts on Cd alleviation and soil microbial diversity and structure. The bacterial/biochar composite treatment decreased the fraction of HOAc-extractable Cd by 38.82%, and increased residual Cd by 23.95% compared to the untreated control. Moreover, compared with the untreated control, the composite treatment significantly increased the soil pH by about 1.5 units, and the activities of catalase, urease and invertase enzymes were increased by 42.39%, 30.50% and 31.20%, respectively. Composite treatment increased soil bacterial and fungal alpha diversity, the relative abundance of Bacillus, Streptomyces, Arthrobacter, and Aspergillus species were also increased. Mantel test and correlation analysis indicated that the effects associated with fungal communities in influencing soil properties were lower than that those of bacterial communities by different treatment. Aggregated boosted tree (ABT) models analysis showed that soil chemical proprieties (as determined by SOM, CEC, AN, etc.,) contributed over 50% of the changes in bacterial and fungal communities by the composite treatment. The co-occurrence network results showed that all treatments enhanced the correlation between OUT groups and improved the possible relationships in the bacterial and fungal communities, especially the interrelationships between bacteria and fungi after the Cd fractions stabilized. These findings provide a new insight to optimal strategies for the remediation of Cd-contaminated soil.
生物炭与特定细菌的组合已广泛应用于修复镉污染土壤。但人们对这种复合材料如何影响金属形态的动态分布知之甚少。这一过程伴随着土壤性质和微生物群落结构的改变。应用水稻秸秆生物炭和蜡状芽孢杆菌 RC-1 的复合材料来研究其对 Cd 缓解以及土壤微生物多样性和结构的影响。与未处理的对照相比，细菌/生物炭复合材料处理降低了 HOAc 可提取 Cd 的分数 38.82%，并增加了残留 Cd 的分数 23.95%。此外，与未处理的对照相比，复合处理使土壤 pH 值显著增加了约 1.5 个单位，过氧化氢酶、脲酶和转化酶的活性分别增加了 42.39%、30.50%和 31.20%。复合处理增加了土壤细菌和真菌的 α 多样性，芽孢杆菌、链霉菌、节杆菌和曲霉属的相对丰度也增加了。Mantel 检验和相关分析表明，与不同处理相关的真菌群落对土壤性质的影响低于细菌群落。聚合增强树（ABT）模型分析表明，土壤化学特性（如 SOM、CEC、AN 等）对复合处理引起的细菌和真菌群落变化的贡献超过 50%。共现网络结果表明，所有处理都增强了 OUT 组之间的相关性，并改善了细菌和真菌群落中的可能关系，尤其是在 Cd 形态稳定后细菌和真菌之间的相互关系。这些发现为优化 Cd 污染土壤修复策略提供了新的思路。
