A team of scientists has discovered that the ability of biochar to conduct electricity can significantly affect methane emissions from rice paddies, one of the largest sources of agricultural greenhouse gases worldwide.
Methane is a powerful greenhouse gas, with more than 27 times the warming effect of carbon dioxide. Rice paddies, covering about 9% of global farmland, contribute nearly one-third of agricultural methane emissions. Scientists have long debated whether adding biochar—charcoal-like material made from plant matter—can help reduce or increase these emissions. The new findings, published in Biochar , shed light on why results have been so mixed.
Researchers at Kunming University of Science and Technology created biochar with different levels of electrical conductivity by adding graphene, a highly conductive carbon material. They then tested how these biochars affected methane production in rice soils under controlled laboratory conditions.
The results were striking: soils treated with highly conductive biochar produced up to 69% more methane than untreated soils. The key, the team found, was not changes in the types of microbes present, but rather faster movement of electrons—tiny charged particles that drive many natural processes. Biochar acted like an “electron highway,” allowing dissolved organic matter in the soil to transfer energy more efficiently to methane-producing microbes.
“Our study shows that the conductivity of biochar is a critical factor in determining its impact on greenhouse gas emissions from rice fields,” said co-author Dr. Peng Zhang. “This new understanding can help guide how biochar is designed and applied in agriculture.”
The researchers also used a chemical model of natural organic matter to confirm that biochar’s conductivity speeds up electron transfer in soil. Their work suggests that the physical properties of biochar, such as its surface area and conductivity, should be carefully considered before recommending it as a climate solution.
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Reference: Wu, Y., He, T., Cheng, C. et al. Biochar conductivity enhances methane generation in paddy soil by facilitating electron transfer mediated by dissolved organic matter. Biochar 7 , 85 (2025). https://doi.org/10.1007/s42773-025-00478-8
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About Biochar
Biochar is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field.
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Biochar conductivity enhances methane generation in paddy soil by facilitating electron transfer mediated by dissolved organic matter
24-Jun-2025