Pedosphere 32(6): 866--875, 2022
ISSN 1002-0160/CN 32-1315/P
©2022 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Effective alleviation of Cd stress to microbial communities in mining reclamation soils by thiourea-modified biochar amendment
Yanfeng ZHU1,2, Jing MA1,3, Fu CHEN1,3, Ruilian YU2, Gongren HU2, Yongjun YANG1
1Engineering Research Center of Ministry of Education for Mine Ecological Restoration, China University of Mining and Technology, Xuzhou 221008(China)
2College of Chemical Engineering, Huaqiao University, Xiamen 361021(China)
3Low Carbon Energy Institute, China University of Mining and Technology, Xuzhou 221008(China)
ABSTRACT
      Reclaimed soils in mining area usually display low fertility and present Cd stress. The amendment of modified biochar effectively fixes Cd in soils, enhances soil fertility, and reduces Cd stress in soil microorganisms. However, the effect of thiourea-modified biochar (TBC) on microbial adaptability to Cd stress in mining reclamation soils is still unclear. The present work studied the Cd immobilization and microbial community changes in a mining reclamation soil displaying extreme Cd contamination under TBC amendment. The results indicated that the amendment of TBC significantly enhanced (P < 0.05) soil pH, the content of available phosphorus (AP), and the activities of urease and polyphenol oxidase by 1.3%, 463.4%, 54.4%, and 84.0%, respectively, compared to the control without amendment. The amount of toxicity characteristic leaching procedure-extracable Cd decreased (P < 0.05) by 68.0% in the TBC-amended soil compared with the unamended soil. The structure of soil microbiota was reorganized and the alpha diversity index was increased in the TBC treatment. The TBC amendment increased the relative abundances of Proteobacteria, Bacteroidota, and Zoopagomycota, which were strongly associated (P < 0.01) with higher soil pH and AP. Structural equation model results demonstrated that Cd immobilization was directly influenced by soil pH, AP, and urease, and indirectly affected by bacterial structure in the TBC treatment. The TBC amendment can effectively improve the structural composition of soil bacteria under Cd stress and enhance the pathways of decreasing soil Cd availability as well. The results might facilitate the development of in-situ remediation programs in Cd-contaminated soils in the future.
Key Words:  available phosphorus,bacterial structure,Cd immobilization,enzyme activity,toxicity characteristic leaching procedure-extracable Cd
Citation: Zhu Y F, Ma J, Chen F, Yu R L, Hu G R, Yang Y J. 2022. Effective alleviation of Cd stress to microbial communities in mining reclamation soils by thiourea-modified biochar amendment. Pedosphere. 32(6): 866-875.
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