Using a mixture of microalgae, biochar, and organic manure to increase the capacity of soil to act as carbon sink

Jiajun HU, Hongcheng GUO, Yiyun XUE, Min-tian GAO, Shiping ZHANG, Yiu Fai TSANG, Jixiang LI, Ya-nan WANG, Lei WANG

Research output: Contribution to journalArticle


Purpose Microalgae, biochar, or organic manure (OM) can be used as soil amendments to enhance soil organic carbon (OC) content. In the present study, a mixture of all three was used to test whether they could further improve soil OC content and the soil’s ability to retain and fix carbon.
Materials and methods A laboratory incubation study was carried out to evaluate the efficacy of using microalgae, biochar, OM, or their mixture, as a soil amendment to improve OC in soil extract. Metabolic processes and soil microbial community structuring were analyzed to explore the mechanism by which the mixture increased the capacity of soil to act as a carbon sink.
Results and discussion OC increased markedly (2.9 times its initial level) following the amendment of the soil with a treatment comprising microalgae, biochar, and the highest dose of OM. Microalgal metabolites were utilized by soil microorganisms as a carbon source. Biochar reduced the concentration of extracellular polysaccharides, whereas OM increased extracellular protein concentration. These metabolites affected the relative proportions of different groups of soil microorganisms, thereby increasing the proportion of Rhodobacter and Runella, which exerted a positive synergistic effect on soil OC and increased the soil’s capacity to fix carbon.
Conclusions A mixture including microalga, biochar, and OM as a soil amendment improved the OC of soil extract, and its effect was greater than that of any of its components alone. The findings of this study can help in devising ways to increase the OC content and the CO₂-fixing capacity of the soil. Copyright © 2019 Springer-Verlag GmbH Germany, part of Springer Nature.
Original languageEnglish
Pages (from-to)3718–3727
JournalJournal of Soils and Sediments
Issue number11
Early online date21 May 2019
Publication statusPublished - Nov 2019



Hu, J., Guo, H., Xue, Y., Gao, M.-T., Zhang, S., Tsang, Y. F., . . . Wang, L. (2019). Using a mixture of microalgae, biochar, and organic manure to increase the capacity of soil to act as carbon sink. Journal of Soils and Sediments, 19(11), 3718–3727. doi: 10.1007/s11368-019-02337-z


  • CO₂ fixation
  • Microalgal metabolite
  • Soil amendment
  • Soil microorganisms
  • Synergistic effects