Researchers from the Institute of Agricultural Resources and Regional Planning (IARRP), Chinese Academy of Agricultural Sciences (CAAS), have systematically elucidated the mechanism by which biochar alleviates energy deficiency in maize caused by microplastics. This was achieved through the integration of multiple pieces of evidence, including soil physicochemical properties, metagenomics, plant antioxidant enzyme activities and metabolomics, which revealed that biochar reshapes the rhizospheric microecology and plant metabolic profiles. This study, titled "Biochar counteracts the negative effects of microplastics on physiological and biochemical characteristics and leaf metabolism in Zea mays L.", was published in the Journal of Hazardous Materials.

The ecological risks posed by plastic pollution to the growth and development of crops have become a forefront scientific issue of great concern in the field of agricultural environment. The long-term accumulation of residual agricultural mulch in the soil leads to the formation of micro- and nano-plastics through aging and degradation processes, which may pose potential threats to crop physiological and metabolic functions, soil micro-ecosystem and the sustainable agricultural development . The underlying mechanisms of these effects urgently require in-depth exploration. Biochar (BC), as a functional material with abundant pores and surface functional groups, has demonstrated significant advantages in soil reclamation, pollution control, and carbon removal. However, there is still a lack of systematic scientific understanding regarding the effects of biochar on the rhizospheric microecology and metabolic regulation in plastic contaminated soil.

The research examined exogenously added polyethylene (PET) and polylactic acid (PLA) as two representative microplastics (MPs), along with farmland soil that had undergone agricultural mulching for over ten years, using a greenhouse control experiment. By integrating multiscale analytical techniques, it provides a comprehensive elucidation of the mechanism by which biochar alleviates the energy deficiency caused by microplastics in Zea mays L. They reported three key findings:

• Antioxidant response — Biochar mitigated oxidative stress induced by microplastics, significantly increasing antioxidant enzyme (such as CAT, et al.) activity in maize leaves.

• Soil microbial communities — Biochar enhanced bacterial community diversity in plastic contaminated soils, improving rhizospheric microbial community stability.

• Plant metabolomics — Biochar promotes root glucose metabolism by upregulating lipid metabolism and amino acid biosynthesis pathways, reconstructing the plant energy balance system, and thereby resisting the energy deficiency caused by microplastic pollution stress.

The study provides a new perspective for evaluating the application potential biochar in agriculture, especially for the treatment of emerging contaminants such as microplastics.

Dr. Zhao Shuwen of IARRP is the first author, and Prof. Zhang Qianru is the corresponding author. The research was supported by the State Key Laboratory of Efficient Utilization of Arable Land in China, the Earmarked Fund for China Agriculture Research System, and the CAAS Science and Technology Innovation Project.

Citation: Zhao, S.W., Zhang, Q.R., Chen, X.M., Huang, Q.L., Li, H.N., Siddique, K.H.M. (2025). Biochar counteracts the negative effects of microplastics on physiological and biochemical characteristics and leaf metabolism in Zea mays L. Journal of Hazardous Materials, 496: 139355.

Original article link：

https://doi.org/10.1016/j.jhazmat.2025.139355