Agricultural waste is often seen as a disposal problem, but new research suggests it could be a powerful tool for climate change mitigation. A study published in Agricultural Ecology and Environment finds that converting cotton straw and discarded agricultural plastic film into biochar through a process known as co-pyrolysis could significantly reduce greenhouse gas emissions while improving the sustainability of farming systems in Xinjiang, China.
Xinjiang is China’s largest cotton producing region and one of its most important agricultural areas. Every year, millions of tons of cotton straw and plastic mulch film are generated after harvest. Much of this material is either burned, discarded, or poorly recycled, contributing to air pollution, soil degradation, and so called white pollution from residual plastic in farmland.
The research team evaluated how much of this agricultural waste could realistically be collected and converted into biochar, a carbon rich material produced by heating organic matter in the absence of oxygen. Biochar can be used to improve soil fertility, retain nutrients, and store carbon in soils for long periods. Using a life cycle assessment approach, the researchers quantified the potential climate benefits of different waste management strategies.
“Our goal was to understand whether these agricultural residues could be transformed from an environmental burden into a climate solution,” said corresponding author Ronghua Li. “The results show that integrated treatment of cotton straw and plastic mulch film can deliver substantial carbon emission reductions while addressing long standing pollution challenges in cotton producing regions.”
The study found that Xinjiang generates approximately 26 million tons of collectible crop straw each year, with cotton straw accounting for a large share. If cotton straw alone were converted into biochar, it could produce about 3.5 million tons of biochar annually and reduce net greenhouse gas emissions by roughly 10 million tons of carbon dioxide equivalent.
Plastic mulch film, which is widely used to improve crop yields and conserve soil moisture, presents a more difficult challenge. When processed alone, waste plastic film produces very little biochar and delivers limited climate benefits. However, the researchers discovered that combining plastic film with cotton straw in a co-pyrolysis process dramatically improves outcomes.
When recyclable plastic film was co-pyrolyzed with cotton straw at a mass ratio of one to four, biochar yields increased substantially, producing more than 200,000 tons of biochar and achieving a net reduction of approximately 3.4 million tons of carbon dioxide equivalent. Additional climate benefits came from renewable energy generation during pyrolysis, reduced use of chemical fertilizers, and lower emissions of nitrous oxide from agricultural soils.
“Co-pyrolysis changes the equation,” said co corresponding author Jianchun Zhu. “By processing straw and plastic together, we not only improve biochar production but also unlock much greater emission reduction potential compared with treating plastic waste on its own.”
Beyond climate mitigation, the study highlights broader environmental and agricultural benefits. Biochar application can enhance soil structure, improve nutrient efficiency, and support long term soil carbon storage. At the same time, integrated waste treatment reduces open burning and plastic pollution, offering a cleaner and more sustainable pathway for agricultural residue management.
The authors suggest that policy support and financial incentives could accelerate adoption of co-pyrolysis technologies in major cotton producing regions. Such measures would help transform agricultural waste into valuable resources, contributing to China’s carbon neutrality goals while improving soil health and rural sustainability.
“This research shows that climate action and agricultural development do not have to be in conflict,” Li said. “With the right technologies and policies, farm waste can become part of the solution.”
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Journal Reference : Zhao X, Ji M, Bai H, Zeng L, Tang KHD, et al. 2026. Potential of biochar production and carbon emission mitigation through co-pyrolysis of cotton straw and mulch film waste in Xinjiang, China. Agricultural Ecology and Environment 2: e003 doi: 10.48130/aee-0025-0016
https://www.maxapress.com/article/doi/10.48130/aee-0025-0016
About Agricultural Ecology and Environment :
Agricultural Ecology and Environment (e-ISSN 3070-0639) is a multidisciplinary platform for communicating advances in fundamental and applied research on the agroecological environment, focusing on the interactions between agroecosystems and the environment. It is dedicated to advancing the understanding of the complex interactions between agricultural practices and ecological systems. The journal aims to provide a comprehensive and cutting-edge forum for researchers, practitioners, policymakers, and stakeholders from diverse fields such as agronomy, ecology, environmental science, soil science, and sustainable development.
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Potential of biochar production and carbon emission mitigation through co-pyrolysis of cotton straw and mulch film waste in Xinjiang, China
28-Jan-2026