New study reveals how China can cut nitrogen pollution while safeguarding national food security
Biochar Editorial Office, Shenyang Agricultural University
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Minimizing nitrogen-related environmental harm while achieving food security in China
view moreCredit: Xuejun Liu, Wim de Vries, Ying Zhang, Lei Liu5, Lin Ma, Zhenling Cui, Qichao Zhu, Hao Ying, Mingsheng Fan, Weifeng Zhang, Keith Goulding, Tom Misselbrook, Dave Chadwick, Jie Zhang & Fusuo Zhang
A new study published in Nitrogen Cycling presents the most comprehensive assessment to date of how China can reduce nationwide nitrogen pollution while continuing to meet the rising food demands of its population. The research analyzes nearly six decades of data and concludes that smarter nitrogen management could reduce fertilizer use by more than one third, significantly improving air and water quality without compromising crop yields.
Nitrogen fertilizers have played a central role in feeding China since the 1960s, supporting dramatic increases in crop production. Yet the overuse of nitrogen has also created widespread environmental challenges. Excess reactive nitrogen enters the atmosphere as ammonia or reaches groundwater as nitrate, contributing to particulate pollution, acidification of soils, eutrophication of water bodies, biodiversity loss, and risks to human health.
To understand how China can reverse these trends, the research team compiled a national nitrogen budget covering the years 1961 to 2018. They tracked nitrogen inputs from fertilizers, manure, deposition, irrigation, and biological fixation and compared them with crop uptake and losses to air and water. The study also calculated the nitrogen input required to meet national food needs and the critical nitrogen threshold necessary to protect environmental and public health.
The findings reveal acute imbalances. China’s nitrogen inputs rose from 4 Tg per year in 1961 to 48 Tg per year in 2018. Since 1980, actual nitrogen inputs have exceeded the amounts needed for food security. Since 2000, they have also exceeded the environmental safety limits set by acceptable ammonia emissions and nitrate leaching. By 2018, China was using 18 to 20 Tg more nitrogen each year than either food security or environmental protection required.
The study identifies three major sources of nitrogen losses: ammonia emissions, nitrate leaching, and denitrification processes. Together they account for up to 39 percent of total nitrogen inputs. In greenhouse vegetable systems in particular, nitrogen use efficiency can fall as low as 4 percent, with substantial losses to the environment.
Despite these challenges, the researchers outline a feasible path forward. They propose a three step strategy that could reduce total nitrogen inputs from 48 to approximately 31 Tg per year. The first step is to increase recycling of livestock manure. China produces 15.4 Tg of manure nitrogen annually, but less than half currently returns to croplands. Achieving an 80 percent manure recycling rate would reduce fertilizer demand by more than 4 Tg per year.
The second step is to balance fertilizer applications with nitrogen supplied by manure and environmental sources. This adjustment alone could cut fertilizer use by 30 to 35 percent without reducing crop yields.
The third step is to adopt integrated soil and crop management practices, including improved crop varieties, optimal rotations, precision fertilization guided by the 4R principles, and enhanced soil productivity. These improvements could further reduce nitrogen fertilizer use by 20 percent and raise national nitrogen use efficiency to levels comparable with those of Europe.
If implemented together, these actions would not only bring China’s nitrogen input within safe environmental limits but also generate substantial economic benefits. The study estimates that reduced fertilizer purchases would save farmers approximately EUR 14 billion annually. Additional savings of nearly EUR 18 billion could result from improved water quality, reduced health costs, and environmental restoration.
The authors emphasize that achieving these benefits will require coordinated national policy, investments in manure management infrastructure, and widespread adoption of advanced farming practices. They conclude that China now has both the scientific insight and the technological capacity to reconcile food production with ecological safety, creating a model for sustainable agriculture worldwide.
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Journal Reference: Liu X, de Vries W, Zhang Y, Liu L, Ma L, et al. 2025. Minimizing nitrogen-related environmental harm while achieving food security in China. Nitrogen Cycling 1: e010
https://www.maxapress.com/article/doi/10.48130/nc-0025-0010
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About Nitrogen Cycling:
Nitrogen Cycling is a multidisciplinary platform for communicating advances in fundamental and applied research on the nitrogen cycle. It is dedicated to serving as an innovative, efficient, and professional platform for researchers in the field of nitrogen cycling worldwide to deliver findings from this rapidly expanding field of science.
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Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Minimizing nitrogen-related environmental harm while achieving food security in China
Article Publication Date
17-Nov-2025
Dissolved organic matter: Climate change’s double-edged player in global carbon and pollution cycles
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The double-edged environmental effect of dissolved organic matter in global climate change
view moreCredit: Jing Zhao, Qiusheng Yuan, Xin Lei, Thora Lieke, Yang Liu, Christian E.W. Steinberg, Bo Pan, & Baoshan Xing
As global temperatures climb, a critical but often-overlooked component of our ecosystems is stepping into the spotlight: dissolved organic matter, or DOM. Found everywhere from river water to forest soils, DOM acts as a powerful mover of carbon, nutrients, and pollutants. A new review led by scientists from Kunming University of Science & Technology and international partners finds DOM to be both a buffer and a potential accelerator of climate change, playing a surprisingly complex role in the planet’s environmental balance.
DOM is a diverse mixture of molecules released from decomposed plants, microorganisms, and even plastics. When temperatures rise and rainfall patterns shift, DOM’s molecular structure changes, altering its environmental behavior and biological effects. According to the researchers, climate-induced changes are making DOM both a concern and a solution in the face of global warming.
“Our work highlights how global warming can push DOM to act as a carbon source, fueling greenhouse gas emissions, or as a carbon sink, capturing carbon for long periods,” says lead author Dr. Jing Zhao. “What’s more, these processes are shaped by climate-driven events like droughts, floods, wildfires, and permafrost thaw.”
Key Findings
Global warming increases the aromaticity and carboxyl content of DOM, resulting in molecules with either higher stability or higher reactivity. The fate of these molecules helps determine whether DOM stores carbon or releases it to the atmosphere.
Changes in DOM affect how heavy metals, organic chemicals, and microplastics move and transform in the environment. New forms of DOM can enhance pollutant binding or, under some conditions, boost pollutant mobility and ecological risks.
Biological effects of DOM shift with its amount and structure. It can act as a nutrient and protective barrier for organisms, but excessive or chemically altered DOM may stress organisms by increasing reactive oxygen species or disrupting nutrient uptake.
DOM has a feedback relationship with climate change. Positive feedbacks, like increased CO2 and methane emissions from thawed permafrost, can intensify warming. Negative feedbacks, like long-term carbon storage in peatland DOM, can help offset emissions.
Broader Impacts for Public and Environment
The researchers found that DOM’s double-edged role extends to pollutant regulation. Structural changes in DOM can both reduce and intensify the bioavailability of toxic substances such as mercury, pharmaceuticals, and microplastics. For instance, as drought and warming make DOM more aromatic, its ability to bind to pollutants often grows. However, these same changes may turn DOM from a protective shield into a vector for toxins, especially in increasingly polluted and plastic-contaminated waters.
Climate change also increases DOM’s interaction with pollutants and living organisms. DOM can shield aquatic life from some stresses but can also increase pollutant uptake or trigger oxidative stress, depending on its concentration and molecular quality. Researchers urge caution in assuming all DOM changes benefit ecosystems.
Policy Implications and Future Directions
The authors call for governments and research institutions to enhance monitoring of DOM quality in the environment, including key chemical ratios and redox potential. They recommend establishing long-term observational networks to track DOM dynamics across ecosystems and guide climate change mitigation efforts.
“Dissolved organic matter is at the intersection of climate, water chemistry, and ecology,” says Dr. Baoshan Xing, co-author and professor at the University of Massachusetts Amherst. “Understanding DOM’s shifting impact is essential for protecting ecosystems and human well-being in a warming and increasingly complex world.”
The study emphasizes the urgent need for interdisciplinary collaboration to improve analytical methods for DOM and to quantify its multiple environmental roles. Such efforts can help build robust policies aimed at climate adaptation, pollution reduction, and biodiversity conservation.
About the Study
This research was supported by the National Natural Science Foundation of China and the Yunnan Provincial Scientific and Technological Projects. For media inquiries, please contact Dr. Bo Pan at Kunming University of Science & Technology.
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Journal reference: Zhao J, Yuan Q, Lei X, Lieke T, Liu Y, et al. 2025. The double-edged environmental effect of dissolved organic matter in global climate change. Environmental and Biogeochemical Processes 1: e009
https://www.maxapress.com/article/doi/10.48130/ebp-0025-0009
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About the Journal:
Environmental and Biogeochemical Processes is a multidisciplinary platform for communicating advances in fundamental and applied research on the interactions and processes involving the cycling of elements and compounds between the biological, geological, and chemical components of the environment.
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Method of Research
Literature review
Subject of Research
Not applicable
Article Title
The double-edged environmental effect of dissolved organic matter in global climate change
Article Publication Date
19-Nov-2025
Livestock manure linked to the rapid spread of hidden antibiotic resistance threats in farmland soils
Biochar Editorial Office, Shenyang Agricultural University
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Heavy metals and antibiotic resistance genes in large-scale livestock farming environments: pollution characteristics, driving factors, and risks to humans
view moreCredit: Wenbin Liu, Wenguang Zhou, Chenxi Fu, Jianfeng Yu, Gaijuan Hou, Meiyan Zhang, Liujie He & Huijun Ding
Large-scale livestock farming is accelerating the spread of antibiotic resistance and heavy metal contamination in agricultural soils at a pace and scale that poses new risks to global food safety and public health, new research reveals. Scientists have uncovered how even “low-risk” organic fertilizers like dried poultry manure can inadvertently drive a dramatic surge in dangerous antibiotic resistance genes, once released into vegetable plots used for food crops.
The peer-reviewed study, published this week in Biocontaminant, focused on pig and chicken farms near Poyang Lake, China’s largest freshwater lake. Researchers examined how heavy metals and antibiotic resistance genes (ARGs) interact and proliferate in soils, using advanced DNA sequencing and molecular tools to track their movement from livestock manure to farmland.
“Antibiotic resistance genes are recognized as a global threat, leading to 700,000 deaths each year,” said lead author Dr. Wenbin Liu, of the School of Resources and Environment at Nanchang University. “Our findings show that intensive livestock farming doesn’t just pollute the air and water. It seeds the soil with hidden genetic time bombs that can move rapidly between bacteria and spread into the wider environment.”
Key Findings
Pig farms released far greater quantities of heavy metals such as zinc and copper into neighboring soils than chicken farms. Both metals are widely used as feed additives.
Antibiotic resistance genes were transferred to vegetable-growing soils mainly through manure applications, with the greatest surge in risk found in plots fertilized with chicken manure.
In one testing site, the health risk index for antibiotic resistance genes rose more than 16,000-fold compared to untreated soil after chicken manure was applied. Even manure classified as low-risk for resistance genes initially, once spread, created new opportunities for risk gene multiplication and exchange.
Soils treated with manure harbored a wider variety of high-risk resistance genes, including those conferring resistance to tetracycline, sulfonamides, and multiple other drug classes. Many of these genes were not present in the original manure but appeared post-application, indicating environmental selection and spread.
The team found that the presence of heavy metals plays a subtle but powerful role in this process. Rather than promoting resistance directly, these metals increase the abundance of mobile genetic elements (MGEs), tiny segments of DNA that transfer resistance genes between bacteria like pieces of genetic machinery. The bacterial group Firmicutes was identified as a particularly important host. This mobile DNA accelerates the spread of resistance genes from manure bacteria to soil microbes, making the soil a hotbed of hidden antibiotic resistance exchange.
Public Health and Food Safety Implications
The findings challenge common assumptions that dried or processed livestock manures are universally safe for use on food crops. “Simply drying manure may lower the overall number of resistance genes but does not eliminate those with the greatest risk,” said co-author Dr. Huijun Ding. “Our data underlines the urgency of developing science-driven management strategies for manure treatment and application on farmland.”
Solutions and Recommendations
The researchers point to advanced manure treatment options as vital to reducing soil contamination and protecting food safety. Processes such as hyperthermophilic composting, which uses high temperatures to disable both pathogens and resistance genes—can produce safer fertilizers. Similarly, hydrothermal carbonization, though technologically demanding, can remove resistant bacteria and genes entirely.
The team also advocates for prevention at the source, including smarter regulation of antibiotic and heavy metal use in animal feed, especially in large-scale farming. “Managing livestock waste is no longer just about odors or nutrients, but about safeguarding the genetic integrity of our food system,” the study concludes.
About the Study
This research was funded by the Jiangxi Provincial Outstanding Youth Foundation and the Jiangxi Provincial Natural Science Foundation. For more information, contact Dr. Huijun Ding at Nanchang University.
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Journal reference: Liu W, Zhou W, Fu C, Yu J, Hou G, et al. 2025. Heavy metals and antibiotic resistance genes in large-scale livestock farming environments: pollution characteristics, driving factors, and risks to humans. Biocontaminant 1: e006
https://www.maxapress.com/article/doi/10.48130/biocontam-0025-0007
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About Biocontaminant:
Biocontaminant is a multidisciplinary platform dedicated to advancing fundamental and applied research on biological contaminants across diverse environments and systems. The journal serves as an innovative, efficient, and professional forum for global researchers to disseminate findings in this rapidly evolving field.
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Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Heavy metals and antibiotic resistance genes in large-scale livestock farming environments: pollution characteristics, driving factors, and risks to humans
Article Publication Date
18-Nov-2025
