Thursday, March 26, 2026

Turning crop waste into climate solutions: Biochar reduces greenhouse gas emissions in bamboo forests

Biochar Editorial Office, Shenyang Agricultural University

image:
Opposing effects of maize straw and its biochar on soil N2O emissions by mediating microbial nitrification and denitrification in a subtropical Moso bamboo forest
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Credit: Mouliang Xiao, Caixian Tang, Zhenhui Jiang, Jiashu Zhou, Yu Luo, Tida Ge, Lixia Pan, Bing Yu, Yanjiang Cai, Jason C. White & Yongfu Li

A new study reveals that converting agricultural waste into biochar could significantly reduce emissions of nitrous oxide, a potent greenhouse gas, from forest soils. The findings offer a promising strategy for climate-smart land management in rapidly growing bamboo ecosystems.

“Transforming crop residues into biochar can shift soils from being a source of greenhouse gases to a potential climate solution,” said the study’s corresponding author. “Our results highlight how small changes in soil management can have large environmental benefits.”

Nitrous oxide, or N2O, is a powerful greenhouse gas with a global warming potential far greater than carbon dioxide. It is commonly released from soils through microbial processes linked to nitrogen cycling. In managed forest systems, such as subtropical Moso bamboo forests, fertilization and organic amendments can further increase these emissions.

In the new study, researchers compared the effects of maize straw and its derived biochar when added to bamboo forest soils. While both materials originate from the same agricultural residue, they behaved very differently once incorporated into the soil.

The team found that adding raw maize straw increased N2O emissions by 16 to 27 percent. In contrast, applying biochar reduced emissions by 17 to 20 percent. This striking contrast highlights how processing agricultural waste can fundamentally alter its environmental impact.

The difference lies in how these materials interact with soil microbes and nitrogen availability. Straw releases easily decomposable organic matter, which fuels microbial activity. This process increases the availability of nitrogen in forms such as ammonium and nitrate, which microbes convert into N2O during nitrification and denitrification.

Biochar, however, acts in the opposite way. Produced by heating biomass at high temperatures under limited oxygen, biochar has a porous structure and strong adsorption capacity. When added to soil, it reduces the availability of nitrogen compounds and alters microbial activity.

The study showed that biochar suppressed key microbial genes responsible for producing N2O, including those involved in nitrification and denitrification pathways. At the same time, it increased the abundance of microbes carrying the nosZ gene, which encodes an enzyme that converts N2O into harmless nitrogen gas.

“This dual effect is critical,” the authors explained. “Biochar not only reduces the production of nitrous oxide but also enhances its consumption, leading to an overall reduction in emissions.”

The research also found that biochar decreased the activity of enzymes linked to nitrogen cycling, further limiting the processes that generate N2O. Meanwhile, straw had the opposite effect, stimulating these enzymes and accelerating nitrogen transformations.

Importantly, the study highlights the central role of soil microbial communities in controlling greenhouse gas emissions. By influencing microbial genes and metabolic pathways, soil amendments can either amplify or mitigate climate impacts.

Moso bamboo forests, widely distributed in subtropical regions, are an important resource for timber and carbon storage. However, intensive management practices, including fertilization and organic amendments, can increase their greenhouse gas footprint. The findings suggest that replacing straw with biochar could help reduce these emissions without compromising soil health.

Beyond bamboo forests, the implications extend to agricultural and forestry systems worldwide. Converting crop residues into biochar provides a sustainable pathway to recycle waste, improve soil quality, and mitigate climate change simultaneously.

The researchers emphasize that future work should explore different types of biochar and environmental conditions to better understand how these effects vary across ecosystems. They also suggest that combining biochar with other sustainable practices could further enhance its benefits.

As global efforts intensify to reduce greenhouse gas emissions, this study provides compelling evidence that smarter use of agricultural waste can play a meaningful role in climate solutions.

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Journal Reference: Xiao, M., Tang, C., Jiang, Z. et al. Opposing effects of maize straw and its biochar on soil N2O emissions by mediating microbial nitrification and denitrification in a subtropical Moso bamboo forest. Biochar 8, 50 (2026).

https://doi.org/10.1007/s42773-025-00545-0

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About Biochar

Biochar (e-ISSN: 2524-7867) 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.

Journal

Biochar

DOI

10.1007/s42773-025-00545-0

Method of Research

Experimental study

Article Title

Opposing effects of maize straw and its biochar on soil N2O emissions by mediating microbial nitrification and denitrification in a subtropical Moso bamboo forest

How plants stop growing to survive stress

Retired scientist’s persistence reveals insight to boost farm yields

University of California - Riverside

Researcher and her lab plants — image:
Wilhelmina van de Ven and the laboratory plants at UC Riverside.
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Credit: Stan Lim/UCR

UC Riverside researchers have identified a mechanism that allows plants to rapidly slow growth in response to extreme environmental stress. The finding could help farmers grow more resilient crops, and one researcher continued the work years into retirement to uncover it.

The rapid response system is based on a process inside plant cells that produces compounds needed for growth, development, and survival. If even one of the key enzymes in this process fails, the plant cannot live.

Under stress conditions such as intense light, this biological pathway behaves in an unexpected manner. Rather than being governed by changes in gene expression, a standard mechanism in biology, it is modulated instantly through direct alterations in enzyme activity.

In most living things, cells adjust their RNA levels to alter protein production, which then changes the balance of other important molecules. But this process takes time that plants may not have when faced with sudden light or heat stress. In plants, the response is much faster. Stress directly alters the activity of enzymes already present in the cell, allowing leaves to respond immediately without waiting for new proteins to be made.

“This kind of response has to be immediate,” said Katie Dehesh, UCR distinguished professor of molecular biochemistry. “Changing gene expression takes time, but modifying enzyme activity allows the plant to react right away and survive.”

Reactive oxygen molecules interfere with the enzymes, reducing their activity and slowing the pathway. At the same time, new compounds build up, blocking earlier steps in the process and preventing some enzymes from working efficiently.

The immediate effect is protective. By limiting the pathway’s output, the plant reduces production of growth-related compounds, effectively pausing development while it copes with stress.

Over time, a second phase begins as the plant adjusts its internal machinery to prolonged stress. These longer-term changes help the plant adapt, but often at a cost, redirecting resources away from growth and resulting in smaller or slower development.

There have been many efforts to engineer plants to increase crop yields and drought tolerance as well as produce valuable molecules like carotenoids, which protect against damage. However, these engineering efforts often fail because they did not account for the two-stage response identified by the Dehesh laboratory and described in the Proceedings of the National Academy of Sciences.

The breakthrough was the result of painstaking work led by Mien van de Ven, a former lab manager and research supervisor who continued contributing to the project even after retiring. She systematically measured intermediate compounds at each step of the pathway, even though they are present in extremely small amounts.

“There were both conceptual and experimental challenges,” Dehesh said. “The metabolites are at very low levels, and even identifying them required careful, step-by-step work.”

The team’s progress began with an unexpected clue. A mutation in one enzyme caused plants to grow smaller without dying. Following this lead, the researchers analyzed each step of the pathway and discovered that one downstream compound accumulated at unusually high levels. They eventually determined why. The compound binds to an upstream enzyme, blocking it and slowing the entire pathway.

Proving this interaction was technically difficult. The team had to isolate delicate enzymes and recreate the right conditions for them to function outside the plant. Even then, the work was challenging. Proteins can become unstable outside their natural environment, and excess materials can interfere with measurements.

“It took a lot of time to get all the components working together under the right conditions,” van de Ven said.

The work culminated in a clearer picture of how plants balance survival and growth under stress. Because similar pathways exist in bacteria, the findings may reflect a broader strategy used by living organisms to respond to environmental change. The research also has practical applications. Enhancing this natural pathway could help scientists develop crops that are more resilient to drought and high light as well as temperature extremes and salinity.

Equally notable is the path to the discovery. Van de Ven continued working on the project for two years after retiring, returning to the lab to complete key experiments.
“She just kept going,” Dehesh said. “It shows how much impact one person can have on science through dedication.”

For van de Ven, now enjoying baking and line dancing in retirement, the decision was simple: finish what she started.

“I didn’t know it would take as long as it did,” van de Ven said. “But it was worth continuing to see it through.”

Wilhelmina van de Ven.
Credit
Stan Lim/UCR