Biochar can reshape how soils respond to warming, but the effect depends on the soil
New study shows that wood biochar may lower the temperature sensitivity of nitrous oxide emissions in agricultural soil while increasing it in forest soil
image:
Biochar modulates temperature sensitivity of soil N2O emissions: soil-specific mechanisms
view moreCredit: Siyu Luo, Zhibo Li, Jing Hu & Xiaolin Liao
As the planet warms, soils may release more nitrous oxide, a powerful greenhouse gas linked to agriculture, fertilizer use, and microbial nitrogen cycling. A new study published in Biochar shows that biochar, a carbon-rich material made by heating biomass with limited oxygen, can change how strongly soil nitrous oxide emissions respond to rising temperatures. But the effect is not one-size-fits-all.
Researchers tested two contrasting soils, agricultural soil and forest soil, with two types of biochar made from wood and rice husk. They applied the biochars at two rates, 1% and 3%, and incubated the soils at 10 °C, 20 °C, and 30 °C. The team focused on Q10, a measure of how much a biological process changes when temperature rises by 10 °C.
The study found that nitrous oxide emissions increased with warming in both soils, but forest soil was more temperature-sensitive than agricultural soil. Q10 values were higher in forest soil, ranging from 1.63 to 2.84, compared with 1.13 to 1.63 in agricultural soil. This suggests that warming may have a stronger effect on nitrous oxide release in soils with more active nitrogen cycling and higher nutrient availability.
“Biochar is often discussed as a climate mitigation tool, but our findings show that its effects depend strongly on the soil environment,” said corresponding author Xiaolin Liao. “The same biochar treatment can push soil nitrogen processes in different directions depending on whether the soil is agricultural or forest soil.”
Among all treatments, only high-rate wood biochar significantly changed the temperature sensitivity of nitrous oxide emissions. In agricultural soil, it lowered Q10, meaning that nitrous oxide emissions became less responsive to warming. The researchers found that this treatment strongly reduced nitrate availability and weakened the temperature response of nitrate, creating greater substrate limitation for nitrous oxide production.
In forest soil, however, high-rate wood biochar had the opposite effect. It increased Q10, even though biochar generally reduced total nitrous oxide emissions in that soil. The authors suggest that wood biochar may have altered short-term nitrate retention and strengthened the coupling between nitrification and nitrate-consuming processes, making nitrous oxide emissions more sensitive to temperature changes.
“This result is important because it shows that reducing total emissions and reducing warming sensitivity are not always the same goal,” said first author Siyu Luo. “A treatment may suppress nitrous oxide emissions overall, while still changing how emissions respond to future warming.”
The team also measured soil pH, dissolved organic carbon, ammonium, nitrate, microbial biomass carbon, and several nitrogen-related microbial functional genes. Their path modeling showed that temperature was the dominant driver of nitrous oxide emissions, acting through changes in substrate availability, soil pH, and microbial genes. Biochar acted as a secondary modulator, shaping the soil conditions that control microbial nitrogen transformations.
The findings add nuance to the growing interest in biochar as a climate-smart soil amendment. Rather than applying biochar with a universal expectation of greenhouse gas mitigation, the study suggests that soil type, biochar feedstock, and application rate should all be considered when designing biochar strategies under climate change.
“Our study highlights the need for soil-specific biochar management,” Liao said. “To use biochar effectively for nitrous oxide mitigation, we need to understand not only whether it lowers emissions, but also how it changes the sensitivity of those emissions to warming.”
The research provides new mechanistic insight into how biochar, temperature, and microbial nitrogen cycling interact, offering guidance for more targeted soil management in a warming world.
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Journal Reference: Luo, S., Li, Z., Hu, J. et al. Biochar modulates temperature sensitivity of soil N2O emissions: soil-specific mechanisms. Biochar 8, 81 (2026).
https://doi.org/10.1007/s42773-026-00591-2
Journal
Biochar
Method of Research
Experimental study
Article Title
Biochar modulates temperature sensitivity of soil N2O emissions: soil-specific mechanisms
A smarter way to grow rice could save
water, boost yield, and reduce ammonia
loss
New field study shows that alternate wetting and drying irrigation combined with nitrogen-loaded biochar can help rice farming address food security, water scarcity, and environmental pressure at the same time
image:
Closing the rice production trilemma: AWD and nitrogen-loaded biochar synergy achieves co-benefits in yield improvement, water saving, and ammonia mitigation
view moreCredit: Hongyang Chen, Guangyan Liu, Yang Sun, Fuzheng Gong, Daocai Chi & Qi Wu
Rice feeds more than half of the world’s population, but producing it often requires large amounts of water and nitrogen fertilizer. Conventional flooded rice fields can support stable yields, yet they also place heavy pressure on water resources and contribute to ammonia emissions from agriculture. A new two-year field study published in Biochar suggests that a combined strategy using alternate wetting and drying irrigation and nitrogen-loaded biochar may offer a practical path toward more sustainable rice production.
Researchers tested the approach in paddy fields in Northeast China, comparing conventional continuous flooding with alternate wetting and drying, known as AWD. They also evaluated the addition of nitrogen-loaded biochar, a straw-derived biochar engineered to hold ammonium nitrogen and release it more gradually in soil.
The results point to a promising “triple win.” Compared with continuous flooding, AWD alone reduced water use by 14.17 to 15.56 percent while increasing rice yield by 2.23 to 5.11 percent. When nitrogen-loaded biochar was added under AWD, rice yields increased further by 6.70 to 12.55 percent, while water use dropped by another 6.81 to 12.37 percent compared with AWD without biochar.
“Rice production is facing a difficult balance between feeding people, saving water, and reducing environmental impacts,” said corresponding author Guangyan Liu of Shenyang Agricultural University. “Our study shows that these goals do not have to compete with each other. By pairing smarter irrigation with nitrogen-loaded biochar, farmers may be able to improve yield while using less water and reducing nitrogen losses.”
A major concern in nitrogen-intensive rice farming is ammonia volatilization, a pathway by which nitrogen escapes from soil into the atmosphere. The study found that nitrogen-loaded biochar alone could increase ammonia volatilization under continuously flooded conditions, likely because it added a concentrated nitrogen source. However, this risk was greatly reduced when biochar was combined with AWD. Under AWD, the biochar-supported system consistently maintained lower ammonia loss than continuously flooded systems with biochar.
The researchers suggest that the synergy comes from two complementary mechanisms. AWD creates cycles of wetting and drying that can improve root activity and soil nitrogen dynamics, but it may also make nitrogen availability less predictable. Nitrogen-loaded biochar helps buffer this instability by retaining ammonium in its pore structure and releasing nitrogen in a more controlled way. At the same time, the biochar can improve soil water retention during drying periods, supporting plants when water is limited.
Using partial least squares path modeling, the team found that both AWD and nitrogen-loaded biochar directly improved rice nitrogen accumulation and reduced water consumption, contributing to yield gains. AWD also directly reduced ammonia volatilization and positively influenced yield.
“These findings provide a scalable framework for rice systems under increasing climate and resource pressures,” said corresponding author Qi Wu. “The combination of AWD and nitrogen-loaded biochar can help align rice production with the goals of food security, clean water, and climate action.”
The study highlights a next-generation management strategy for rice farming, especially in regions where water scarcity and nitrogen loss are growing concerns. While further work is needed to evaluate long-term field performance, economic feasibility, and site-specific recommendations, the findings show that integrated water and nitrogen management can move rice production beyond trade-offs and toward shared benefits for farmers and the environment.
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Journal Reference: Chen, H., Liu, G., Sun, Y. et al. Closing the rice production trilemma: AWD and nitrogen-loaded biochar synergy achieves co-benefits in yield improvement, water saving, and ammonia mitigation. Biochar 8, 79 (2026).
https://doi.org/10.1007/s42773-026-00602-2
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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.
Follow us on Facebook, X, and Bluesky.
Journal
Biochar
Method of Research
Experimental study
Article Title
Closing the rice production trilemma: AWD and nitrogen-loaded biochar synergy achieves co-benefits in yield improvement, water saving, and ammonia mitigation
Tea powered iron nanoparticles help biochar fertilizers feed crops more slowly and sustainably
A green coating made with tea extract, iron nanoparticles, cellulose, and biochar could reduce nutrient loss, improve tomato growth, and lower fertilizer related greenhouse gas emissions
image:
Green-synthesized iron nanoparticles enhance CMC/PVA coatings for biochar‑zeolite slow‑release fertilizers
view moreCredit: Mengqiao Wu, Zefeng Ruan, Yuyuan Wu, Yang Cheng, Yuting Hong, Qinglin Gu, Yiting Zhang, Jialin Wei, Xiaowen Zhang, Chang Dong, Xu Zhao, Yongfu Li, Chengfang Song & Bing Yu
A new study published in Biochar presents a greener way to make slow-release fertilizers that could help farmers grow healthier crops while reducing nutrient loss to the environment.
Researchers developed a biochar-zeolite slow-release fertilizer coated with a biodegradable CMC/PVA film reinforced by iron nanoparticles made using tea extract. The resulting material, named CMC/PVA/0.5Fe-SRF, was designed to release nutrients more gradually, retain soil moisture, and improve fertilizer efficiency.
“Conventional fertilizers often release nutrients faster than plants can absorb them, which leads to waste, water pollution, and greenhouse gas emissions,” said corresponding author Chengfang Song. “Our goal was to design a fertilizer that works more like a timed delivery system, supplying nutrients steadily while using environmentally friendly materials.”
The team used green tea extract as a natural reducing agent to synthesize tea extract iron nanoparticles, or T-FeNPs. These nanoparticles were then incorporated into a coating made from carboxymethyl cellulose and polyvinyl alcohol, two film-forming materials known for their biodegradability and compatibility with agricultural applications. The coated fertilizer core contained zeolite, nitrogen-phosphorus-potassium fertilizer, and rice straw biochar, combining nutrient supply with porous materials that can help retain ions and water.
In soil leaching tests, the best performing formulation, CMC/PVA/0.5Fe-SRF, reduced cumulative nitrogen release to 58.47 percent and phosphorus release to only 15.82 percent over 30 days. This was substantially lower than conventional NPK fertilizer and also better than coated fertilizers without iron nanoparticles. The researchers found that the tea derived iron nanoparticles helped fill pores in the coating, making the membrane denser and more hydrophobic. This created a more difficult pathway for water to enter and for dissolved nutrients to escape.
“The iron nanoparticles act like tiny reinforcements inside the coating,” said corresponding author Bing Yu. “They strengthen the barrier, slow down water penetration, and provide active sites that can bind phosphate. This gives the fertilizer a more controlled nutrient release profile.”
The fertilizer also showed promising results in tomato cultivation. Plants treated with CMC/PVA/0.5Fe-SRF reached the greatest height, produced the highest fresh and dry biomass, and maintained strong root growth. Compared with conventional NPK fertilizer, the optimized coated fertilizer increased fresh biomass from 17.6 g to 20.77 g and dry biomass from 2.03 g to 2.88 g. The researchers suggest that sustained nutrient supply, improved soil water retention, and the micronutrient role of iron all contributed to the growth benefits.
Post-harvest soil analysis further showed that the iron reinforced slow-release fertilizer improved soil nutrient retention. The treatment increased total nitrogen, phosphorus, potassium, cation exchange capacity, and organic matter related indicators, while maintaining stable soil pH. These results suggest that the material may support both crop productivity and soil health.
The study also evaluated economic and environmental potential. The estimated production cost of the optimized fertilizer was US$562.02 per ton, and the authors calculated that improved nitrogen use efficiency could help reduce fertilizer related greenhouse gas emissions. In East Asia alone, the potential reduction was estimated at 35.69 million tons of CO₂ equivalent under a fertilizer substitution scenario.
Because the coating uses tea extract, biodegradable polymers, rice straw biochar, and zeolite, the approach aligns with circular agriculture and green chemistry principles. The authors note that further field trials will be needed to validate performance under diverse soils, crops, climates, and farm management systems.
“Our findings show that sustainable fertilizer design can combine plant based chemistry, nanotechnology, and biochar engineering,” Song said. “This strategy offers a practical pathway toward fertilizers that are more efficient for farmers and less burdensome for the environment.”
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Journal Reference: Wu, M., Ruan, Z., Wu, Y. et al. Green-synthesized iron nanoparticles enhance CMC/PVA coatings for biochar‑zeolite slow‑release fertilizers. Biochar 8, 80 (2026).
https://doi.org/10.1007/s42773-026-00592-1
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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.
Follow us on Facebook, X, and Bluesky.
Journal
Biochar
Method of Research
Experimental study
Article Title
Green-synthesized iron nanoparticles enhance CMC/PVA coatings for biochar‑zeolite slow‑release fertilizers
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