Green tea and biochar combine to create smarter fertilizers that boost crops and cut emissions
Biochar Editorial Office, Shenyang Agricultural University
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 reveals an innovative fertilizer technology that could make agriculture more efficient, sustainable, and climate-friendly by combining biochar, natural polymers, and green-synthesized iron nanoparticles.
“Our goal was to design a fertilizer that releases nutrients only when plants need them, while also improving soil health and reducing environmental impacts,” said the study’s corresponding author. “By using plant-based chemistry and biochar, we created a system that works with nature rather than against it.”
Modern agriculture relies heavily on conventional fertilizers, but much of the applied nitrogen and phosphorus is lost through leaching and runoff. This not only wastes resources but also contributes to water pollution and greenhouse gas emissions. To address this challenge, researchers developed a new type of slow-release fertilizer using a hybrid structure that combines biochar, zeolite, and a biodegradable coating.
The key innovation lies in reinforcing this coating with iron nanoparticles synthesized using tea extract, a green and low-cost method that avoids toxic chemicals. These nanoparticles are embedded within a carboxymethyl cellulose and polyvinyl alcohol matrix, forming a protective shell around fertilizer granules.
The results were striking. In soil leaching tests, the optimized formulation reduced cumulative nitrogen release to about 58 percent and phosphorus release to just under 16 percent, significantly lower than conventional fertilizers. This controlled release helps ensure that nutrients remain available in the soil for longer periods, aligning more closely with plant uptake.
The mechanism behind this performance is twofold. First, the iron nanoparticles create a denser coating structure that slows water penetration and nutrient diffusion. Second, they actively bind phosphorus through chemical interactions, further reducing nutrient loss. As illustrated in the graphical abstract on page 2, the system forms a barrier that regulates water entry and nutrient release while improving root uptake efficiency.
When tested in tomato cultivation, the new fertilizer significantly improved plant growth. Treated plants grew taller, developed longer roots, and produced greater biomass compared to those receiving conventional fertilizers. The enhanced performance is attributed to steady nutrient availability, improved soil moisture retention, and the added benefit of iron as a micronutrient.
Soil quality also improved. The study found increases in total nitrogen, phosphorus, potassium, and cation exchange capacity, all indicators of better soil fertility. These changes suggest that the fertilizer not only supports immediate crop growth but also contributes to long-term soil health.
Importantly, the researchers evaluated the economic and environmental potential of the technology. The estimated production cost is about $562 per ton, making it competitive with existing advanced fertilizers. At the same time, improved nitrogen use efficiency could significantly reduce greenhouse gas emissions. The study estimates that widespread adoption could cut emissions by tens of millions of tons of carbon dioxide equivalents, particularly in regions with intensive fertilizer use.
The researchers emphasize that the approach is scalable and aligns with global efforts to develop sustainable agricultural systems. By integrating bio-based materials with nanotechnology, the fertilizer offers a promising pathway to reduce environmental impacts while maintaining high crop productivity.
Future research will focus on field-scale validation and long-term effects on soil ecosystems, but the findings already point to a powerful new strategy for greener farming.
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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.
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Journal
Biochar
Method of Research
Experimental study
Article Title
Green-synthesized iron nanoparticles enhance CMC/PVA coatings for biochar‑zeolite slow‑release fertilizers
Biochar reshapes climate-driven soil emissions, but effects depend on soil type
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Biochar modulates temperature sensitivity of soil N2O emissions: soil-specific mechanisms
view moreCredit: Siyu Luo, Zhibo Li, Jing Hu & Xiaolin Liao
A new study reveals that biochar, a carbon-rich material increasingly used in agriculture, can significantly influence how soils respond to warming when releasing nitrous oxide, a potent greenhouse gas. The findings highlight that biochar does not act uniformly across environments, but instead produces sharply different outcomes depending on soil type and conditions.
“Biochar is often promoted as a climate solution, but its interaction with temperature is more complex than we expected,” said corresponding author Xiaolin Liao. “Our results show that the same biochar can either dampen or amplify the temperature sensitivity of nitrous oxide emissions depending on the soil.”
Nitrous oxide is nearly 300 times more powerful than carbon dioxide in trapping heat over a century and is primarily emitted from soils through microbial processes. As global temperatures rise, understanding how these emissions respond to warming is critical for predicting climate feedbacks and designing mitigation strategies.
In this study, researchers conducted controlled incubation experiments using two contrasting soils: agricultural soil and forest soil. They tested two types of biochar, derived from wood and rice husks, applied at different rates and exposed to temperatures ranging from 10 to 30 degrees Celsius.
The results showed that temperature strongly increased nitrous oxide emissions in both soils. However, the sensitivity of emissions to temperature, known as Q10, differed substantially. Forest soils exhibited higher temperature sensitivity than agricultural soils, indicating a stronger response to warming.
Biochar played a secondary but important role. Notably, only high-rate wood biochar significantly altered temperature sensitivity. In agricultural soil, it reduced sensitivity, meaning emissions became less responsive to warming. In contrast, in forest soil, the same biochar increased sensitivity, suggesting emissions could rise more sharply with temperature.
The researchers traced these differences to how biochar interacts with nitrogen availability and microbial processes. In agricultural soil, biochar reduced nitrate levels, limiting the substrates needed for microbial production of nitrous oxide. This constraint made microbial activity less responsive to temperature changes.
In forest soil, however, biochar altered nitrogen cycling in a different way. It promoted tighter coupling between nitrification and denitrification processes, which are key microbial pathways that produce and consume nitrous oxide. This enhanced coupling made emissions more sensitive to temperature fluctuations.
“Our findings suggest that biochar changes not just how much nitrous oxide is emitted, but how emissions respond to warming,” said Liao. “This has important implications for predicting future greenhouse gas dynamics.”
The study also used statistical modeling to compare the relative influence of temperature and biochar. The results showed that temperature remained the dominant driver of nitrous oxide emissions, while biochar acted as a modulator by altering soil chemistry and microbial activity.
Importantly, biochar consistently reduced total nitrous oxide emissions in forest soils, but its effects in agricultural soils were more variable. This underscores the need for tailored approaches when applying biochar as a climate mitigation tool.
The researchers emphasize that these findings challenge the assumption that biochar universally reduces greenhouse gas emissions. Instead, its effectiveness depends on soil properties, application rates, and environmental conditions.
“As climate change continues to intensify, we need more precise strategies,” Liao said. “Biochar has great potential, but it must be applied in a soil-specific and context-aware way.”
The study provides new insights into how soil management practices interact with warming, offering guidance for developing more effective and targeted approaches to reduce greenhouse gas emissions from soils.
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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
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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
Biochar modulates temperature sensitivity of soil N2O emissions: soil-specific mechanisms
Tailored biochar strategies boost alfalfa growth and resilience in saline soils
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Contrasting acidic and alkaline biochar reprogram alfalfa metabolism and rhizosphere microbiomes in saline-alkali soils
view moreCredit: Jie Liu, Ziyue Shi, Lan Zhang, Runqiu Feng, Guorui Zhang, Hao Zou, Gangsheng Wang & Yunfeng Yang
Soil salinization is a growing global threat that reduces crop yields and limits sustainable agriculture, especially in arid and semi-arid regions. A new study shows that carefully designed biochar amendments can significantly improve plant growth and soil health in these challenging environments by reshaping both plant metabolism and soil microbial communities.
Researchers investigated how two contrasting types of biochar, an acid-modified version and a conventional alkaline form, affect alfalfa growth in saline-alkali soils. Their findings reveal that not all biochars work the same way. Instead, each type triggers distinct biological processes that help plants cope with salt stress.
“Biochar is often viewed as a general soil conditioner, but our results show that its effects can be highly targeted,” said the study’s lead author. “By selecting the right type and dose, we can actively guide plant metabolism and microbial interactions to improve resilience under stress.”
The study found that both biochars improved soil conditions by reducing salinity and adjusting pH, while also increasing nutrient availability. These changes translated into stronger plant growth and improved forage quality. However, the mechanisms behind these benefits differed markedly between the two biochar types.
Alkaline biochar, applied at higher levels, was particularly effective at enhancing overall plant growth. It stimulated key metabolic pathways related to amino acids, nitrogen use, and antioxidant defenses. These processes help plants maintain cellular balance and reduce damage caused by salt stress. At the same time, alkaline biochar increased the diversity of beneficial soil bacteria, including microbes linked to nutrient cycling and nitrogen fixation.
In contrast, acid-modified biochar showed its strongest effects at lower doses. Rather than primarily boosting growth, it enhanced root development and activated plant defense systems. This included increased production of secondary metabolites such as flavonoids and alkaloids, compounds known to protect plants from environmental stress. It also promoted microbial groups associated with pathogen suppression and organic matter breakdown.
The researchers also uncovered a deeper layer of interaction between plants and soil microbes. Changes in microbial communities were closely linked to shifts in plant metabolism. For example, beneficial bacteria stimulated by alkaline biochar were associated with higher levels of compounds that support growth and stress tolerance. Meanwhile, microbes enriched by acid-modified biochar were connected to defense-related metabolites.
This integrated response highlights that biochar does more than improve soil chemistry. It actively reprograms the biological system surrounding plant roots.
Importantly, the study identified optimal application strategies. A low dose of acid-modified biochar and a higher dose of alkaline biochar delivered the best results. Using too much acid-modified biochar, however, could reduce plant performance, likely due to excessive changes in soil conditions.
“These findings show that precision matters,” the authors noted. “Matching biochar type and dosage to specific soil constraints can maximize benefits while avoiding unintended effects.”
Overall, the research demonstrates that tailored biochar applications offer a scalable and sustainable solution for restoring degraded saline soils. By improving both plant physiology and microbial function, this approach could help farmers maintain productivity under increasingly stressful environmental conditions.
The study provides a roadmap for designing next-generation soil amendments that go beyond simple nutrient addition. Instead, they work by coordinating plant and microbial systems to enhance resilience, productivity, and long-term soil health.
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Journal Reference: Liu, J., Shi, Z., Zhang, L. et al. Contrasting acidic and alkaline biochar reprogram alfalfa metabolism and rhizosphere microbiomes in saline-alkali soils. Biochar 8, 82 (2026).
https://doi.org/10.1007/s42773-026-00595-y
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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
Contrasting acidic and alkaline biochar reprogram alfalfa metabolism and rhizosphere microbiomes in saline-alkali soils
New farming strategy boosts rice yields while saving water and cutting pollution
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
A new study offers a promising solution to one of agriculture’s toughest challenges: how to grow more food while using less water and reducing environmental harm. Researchers have demonstrated that combining a water-saving irrigation technique with an engineered biochar fertilizer can significantly improve rice production while lowering nitrogen pollution.
Rice farming worldwide faces a difficult balancing act. Farmers must maintain high yields to ensure food security, but traditional practices often rely on continuous flooding and heavy nitrogen fertilizer use. These methods consume large amounts of water and contribute to ammonia emissions that harm air quality and ecosystems.
In the new study, scientists tested a combined approach using alternate wetting and drying irrigation, known as AWD, together with nitrogen-loaded biochar, a specially designed soil amendment that stores and gradually releases nutrients. Over two years of field experiments, the team evaluated how this strategy affected rice yield, water use, and ammonia emissions.
“Our goal was to find a practical way to break the trade-offs in rice production,” said one of the study’s authors. “We wanted a solution that could increase yield, reduce water consumption, and minimize environmental impacts at the same time.”
The results were striking. Compared with conventional flooding, AWD alone reduced water use by about 14 to 16 percent while slightly increasing rice yields. When nitrogen-loaded biochar was added, the benefits became even greater. Yields increased by up to 12.5 percent, and additional water savings of up to 12 percent were achieved.
At the same time, the combined approach helped address a key environmental concern. Nitrogen fertilizers often release ammonia gas, which contributes to air pollution and climate impacts. While the biochar alone could increase ammonia emissions under traditional flooding, the use of AWD significantly reduced this effect. In fact, ammonia losses were cut by more than 60 percent compared with conventional practices.
The researchers found that the success of this approach lies in how it reshapes the soil environment. The wet and dry cycles improve soil aeration and microbial activity, helping plants use nitrogen more efficiently. Meanwhile, the biochar acts like a reservoir, storing nitrogen and releasing it in sync with crop demand. Together, these processes enhance nutrient uptake, reduce waste, and support stronger plant growth.
Importantly, the study shows that neither strategy alone is sufficient to achieve all these benefits. The irrigation method and the biochar amendment must work together to deliver consistent gains in productivity and environmental performance.
“This is not just about adding a new material or changing irrigation,” the researchers explained. “It is about integrating water and nutrient management into a coordinated system.”
Beyond improving yields and reducing pollution, the approach also has practical implications for farmers. Increased water efficiency can help agriculture adapt to growing water scarcity, especially in regions facing climate change pressures. At the same time, improved nitrogen use efficiency can lower fertilizer losses and potentially reduce input costs over time.
The findings point to a scalable pathway for more sustainable rice farming. By aligning agricultural productivity with environmental protection, the combined AWD and biochar strategy supports global goals for food security, clean water, and climate action.
As the demand for rice continues to rise, innovations like this could play a key role in transforming how staple crops are produced. The study highlights that smarter management, rather than simply more inputs, may be the key to feeding the future while protecting the planet.
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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
===
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
Biochar boosts soil carbon storage through microbial pathways, but effects vary with soil depth
Biochar Editorial Office, Shenyang Agricultural University
image:
Depth-dependent microbial necromass carbon accumulation responses to long-term biochar amendment in croplands
view moreCredit: Kaiyue Song, Zhiwei Liu, Ruiling Ma, Qi Yi, Jufeng Zheng, Rongjun Bian, Kun Cheng, Shaopan Xia, Xiaoyu Liu, Xuhui Zhang & Lianqing Li
A new long-term field study reveals that biochar, a carbon-rich material derived from biomass, can significantly enhance soil carbon storage by stimulating microbial processes. However, the benefits are not uniform throughout the soil profile, highlighting the importance of looking deeper beneath the surface.
“Soil microbes are central to long-term carbon storage, and our study shows that biochar can reshape how microbial carbon is formed and stabilized,” said the study’s lead author. “But these effects depend strongly on soil depth and nutrient conditions.”
Soils represent the largest terrestrial carbon reservoir, storing more carbon than the atmosphere and vegetation combined. A major portion of this carbon exists not as plant debris, but as microbial necromass, the remains of dead microorganisms. This form of carbon is particularly stable and can persist in soils for long periods, making it critical for climate change mitigation.
To better understand how biochar influences this process, researchers conducted a 12-year field experiment in two contrasting cropland soils. They measured microbial necromass carbon in both topsoil and subsoil layers and complemented their findings with a global meta-analysis of 23 studies.
The results showed a clear pattern. In the topsoil, biochar significantly increased microbial necromass carbon by up to 39 percent, with particularly strong gains in fungal-derived carbon. This increase was linked to improved nutrient availability, greater microbial biomass, and enhanced microbial efficiency. In simple terms, biochar created a more favorable environment for microbes to grow and convert carbon into stable forms.
However, the story changed below the surface. In the subsoil, biochar reduced microbial necromass carbon by as much as 30 percent. The researchers attribute this decline to nutrient limitations. Biochar tends to retain nutrients in the upper soil layers, leaving deeper layers relatively deprived. As a result, microbes in the subsoil increase their metabolic activity to acquire nutrients, accelerating the breakdown of existing carbon rather than building new stores.
“This depth-dependent response is critical,” the authors explained. “If we only look at surface soils, we may overestimate the long-term carbon sequestration potential of biochar.”
The study also found that the effectiveness of biochar depends on environmental conditions. Greater increases in microbial carbon were observed in soils with low initial organic carbon, sandy textures, and in warmer and wetter climates. Long-term application was also essential, with the strongest effects appearing after ten years.
The accompanying meta-analysis confirmed that biochar generally increases microbial necromass carbon across diverse ecosystems, with positive responses observed in more than 80 percent of cases. On average, biochar increased microbial-derived carbon by about 10 percent globally.
Despite these gains, the researchers noted that microbial carbon represents only part of the total soil carbon pool. Because biochar also directly adds stable carbon to soil, the relative contribution of microbial necromass to total soil carbon may decrease even as its absolute amount increases.
Overall, the findings provide new insights into how biochar interacts with soil microbial systems to influence carbon cycling. They also emphasize the need for long-term and depth-specific assessments when evaluating soil carbon sequestration strategies.
“Biochar holds great promise for sustainable agriculture and climate mitigation,” the authors said. “But optimizing its benefits requires a deeper understanding of how soil systems function across space and time.”
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Journal Reference: Song, K., Liu, Z., Ma, R. et al. Depth-dependent microbial necromass carbon accumulation responses to long-term biochar amendment in croplands. Biochar 8, 78 (2026).
https://doi.org/10.1007/s42773-026-00577-0
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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.
Follow us on Facebook, X, and Bluesky.
Journal
Biochar
Method of Research
Experimental study
Article Title
Depth-dependent microbial necromass carbon accumulation responses to long-term biochar amendment in croplands
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