Biochar application on heavy metal immobilization in unsaturated soil with vegetation: a review

ABSTRACT

Biochar, a type of soil amendment, is widely used in heavy metal–polluted soil. It is also effective in enhancing plant performance. However, how biochar affects the soil heavy metal toxicity considering the plant–soil interactions is not well summarized. Therefore, this paper aims to review and summarize the effects of biochar on heavy metal availability in vegetated unsaturated soil. First, this review summarizes the effects of biochar on key parameters of unsaturated soil, including pore size distribution, water permeability, water retention curve, nutrient cycling and soil biota. Then, the mechanism of biochar for managing heavy metals in soil with vegetation is discussed, with a focus on both physical and biochemical aspects. Additionally, the impact of biochar-induced plant growth on the availability of heavy metals in the plant–soil system is explored. Finally, suggestions for future research and applications of biochar are provided. This paper supplies novel outlooks for further study and practice.

KEYWORDS:

• Biochar
• heavy metal contamination
• unsaturated soil
• vegetation

Acknowledgements

The authors acknowledge the Fundamental Research Funds for the Central Universities (4021002305) and the funding from the State Key Laboratory of Subtropical Building Science in South China University of Technology (2022ZC01).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the Fundamental Research Funds for the Central Universities Funding from the State Key Laboratory of Subtropical Building Science in South China University of Technology .