Scientists are highlighting biochar, a carbon-rich material produced from biomass, as a promising solution to help soils store carbon and reduce greenhouse gas emissions, offering new hope in global climate mitigation efforts.
In a new comprehensive review, researchers synthesized current knowledge on how biochar improves soil carbon storage, reduces greenhouse gases, and provides practical frameworks to measure its climate benefits. The findings demonstrate that biochar could play a crucial role in transforming soils into long-term carbon sinks, supporting agricultural sustainability and carbon neutrality goals.
Biochar is created by heating organic biomass such as crop residues, wood, or agricultural waste in low-oxygen conditions. This process converts unstable organic carbon into a stable form that can persist in soil for hundreds to thousands of years. According to the study, biochar not only stores carbon directly but also protects existing soil organic carbon from decomposition, creating a dual carbon sequestration effect.
"Our analysis shows that biochar can simultaneously lock carbon into soils and regulate microbial processes that reduce greenhouse gas emissions," said the study's corresponding author. "This dual function makes biochar a unique and scalable tool for achieving soil carbon neutrality."
The review reveals that biochar improves carbon storage through several interconnected mechanisms. Its highly porous structure physically shields soil organic carbon from microbial breakdown while also promoting the formation of soil aggregates that stabilize carbon. In addition, biochar can stimulate what scientists call a negative priming effect, meaning it slows the decomposition of native soil carbon, further enhancing carbon retention.
Beyond carbon storage, biochar also helps reduce emissions of nitrous oxide and methane, two potent greenhouse gases produced by soil microbial activity. The researchers found that biochar alters soil chemistry, microbial communities, and redox processes, encouraging microbial pathways that convert harmful greenhouse gases into less harmful forms.
"Biochar functions like an electron shuttle in soil," explained the researchers. "It helps regulate microbial reactions that convert nitrous oxide into harmless nitrogen gas, significantly lowering greenhouse gas emissions."
However, the effectiveness of biochar depends strongly on how it is produced and applied. Factors such as feedstock type, pyrolysis temperature, soil characteristics, and application rate all influence biochar's performance. For example, biochar produced at higher temperatures typically has greater stability and carbon sequestration potential, while matching biochar properties to specific soil conditions can maximize environmental benefits.
The study also emphasizes the importance of accurately measuring biochar's climate impact. The authors evaluated multiple carbon accounting approaches, including isotope tracing methods to measure soil carbon changes and life cycle assessments that track emissions across production and application stages. These integrated frameworks are essential for verifying carbon neutrality claims and supporting carbon credit systems.
Large-scale field studies show encouraging results. Biochar applications have been linked to increased soil organic carbon, improved crop yields, and significant reductions in greenhouse gas emissions. The review suggests that optimized biochar deployment could provide both environmental and economic benefits, including reduced fertilizer use and potential revenue from carbon markets.
Despite its promise, the researchers highlight remaining challenges. Long-term field studies are needed to better understand biochar aging, soil interactions, and large-scale implementation strategies. The authors also suggest that advanced engineered biochar materials could further enhance carbon storage while simultaneously remediating soil pollutants.
"Our findings demonstrate that biochar has moved beyond a theoretical concept and is becoming a practical tool for climate-smart agriculture," the authors said. "With proper optimization and verification, biochar could become a cornerstone technology for sustainable soil management and global carbon neutrality."
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Journal reference: Hussain MM, Zhou G, Yang W, Liu L, Zhao C, et al. 2026. Biochar towards soil carbon neutrality: a critical review. Biochar X 2: e006 doi: 10.48130/bchax-0026-0004
https://www.maxapress.com/article/doi/10.48130/bchax-0026-0004
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About the Journal:
Biochar X (e-ISSN: 3070-1686) is an open access, online-only journal aims to transcend traditional disciplinary boundaries by providing a multidisciplinary platform for the exchange of cutting-edge research in both fundamental and applied aspects of biochar. The journal is dedicated to supporting the global biochar research community by offering an innovative, efficient, and professional outlet for sharing new findings and perspectives. Its core focus lies in the discovery of novel insights and the development of emerging applications in the rapidly growing field of biochar science.
