Analysis of a reconstructed 1961–2018 nitrogen budget shows current use exceeds food and environmental limits. Integrating manure recycling, balanced fertilization, and improved soil–crop management could reduce inputs from 48 to about 31 teragrams per year, benefiting food production, environmental quality, and human health.
Nitrogen fertilizers have been vital for feeding a growing population, but their overuse has become a major environmental threat, driving air pollution, water eutrophication, biodiversity loss, and health risks from particulate matter and nitrate-contaminated drinking water. This paradox is especially acute in China, where grain production has more than tripled since the 1960s alongside an almost 100-fold rise in nitrogen fertilizer use. Although hunger was largely eliminated, intensive farming in regions such as the North China Plain and Yangtze River Basin created large nitrogen surpluses. Policies like the 2015 “Zero Increase Action Plan” have curbed fertilizer growth, yet an integrated national framework linking food demand, environmental limits, and combined fertilizer–manure management has remained absent.
A study (DOI: 10.48130/nc-0025-0010) published in Nitrogen Cycling on 17 November 2025 by Xuejun Liu’s team, China Agricultural University, demonstrates that aligning food security with environmental protection in China is achievable by optimizing nitrogen management to substantially reduce excess inputs while maintaining agricultural productivity.
Using a two-part, national-scale approach, the researchers first synthesized existing literature to trace the fate of fertilizer nitrogen (N) across China’s major cropping systems in the 2000s, and then constructed a long-term mass-balance N budget covering 1961–2018 to quantify changes in N inputs (fertilizer, manure, and environmental sources) and outputs (crop uptake and losses to air and water). These analyses were complemented by estimates of “required” N inputs to meet food demand and “critical” N inputs needed to remain within environmental safety thresholds for ammonia emissions and nitrate leaching. The results revealed pronounced differences in nitrogen-use efficiency (NUE) and loss pathways among crops. NUE ranged from 4% to 49%, with cereals such as wheat, maize, and rice consistently outperforming vegetables. Open-field vegetables achieved moderate NUE (~23%), whereas greenhouse vegetables showed extremely low efficiency (~4%). Across cropping systems, ammonia volatilization, nitrate leaching, and total denitrification dominated N losses, while N₂O emissions and runoff were generally ≤1%. Soil residual N also varied, with higher retention (29%–46%) in northern cereals and vegetable systems and lower retention (15%–20%) in rice and southern wheat. At the national level, only 29% of fertilizer N was taken up by crops, 32% remained in soils, and 39% was lost to the environment, mainly through denitrification (16%), ammonia volatilization (14%), and leaching (8%), highlighting particularly severe losses in greenhouse vegetable production driven by excessive N and carbon inputs and frequent irrigation. The historical N budget showed a clear trajectory: low-input, manure-based agriculture in 1961 (fertilizer 0.6 Tg N yr⁻¹, NUE 70%, but inadequate food supply) shifted to fertilizer-driven intensification by 1980 (12.3 Tg N, NUE 47%), followed by large surpluses in 2000 (39.2 Tg inputs) and 2018 (48.0 Tg). Although total inputs declined slightly after 2015 due to the Zero Increase Plan, required N inputs for food security (15–30 Tg N yr⁻¹) and critical environmental thresholds (28–35 Tg N yr⁻¹) indicate that by 2018 actual inputs still exceeded safe levels by about 18–20 Tg N yr⁻¹ (37%–39%), underscoring the urgent need for more efficient and integrated nitrogen management.
This assessment shows that China can substantially reduce its nitrogen surplus without compromising food security through an integrated, system-wide nutrient management strategy. Combining enhanced manure recycling, balanced fertilization, and optimized soil–crop management could cut nitrogen inputs by about 35%, approaching environmentally safe levels. These measures would improve nitrogen-use efficiency, reduce air and water pollution, protect human health, and generate significant economic benefits.
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References
DOI
10.48130/nc-0025-0010
Original Source URL
https://doi.org/10.48130/nc-0025-0010
Funding information
This work was supported by the National Basic Research Program of China (2023YFD1900604, 2023YFD1901404, ZD20232320), the National Natural Science Foundation of China (42277097, 41425007, 42371324), the Gansu Province Outstanding Youth Fund Project (25JRRA629) and the Sino-UK CINAg project on nitrogen (BB/N013468/1).
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