New study reveals how China can cut nitrogen pollution while safeguarding national food security

(Press-News.org) 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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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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