Mitigation potential and social benefits of NH3 emission reduction strategies in maize croplands

Ammonia (NH 3 ) emissions from maize fields are a significant source of reactive nitrogen (N) loss and pose a critical challenge for cropland N management, particularly in intensively farmed regions such as the North China Plain (NCP). Although various NH 3 mitigation strategies have been proposed, studies that have comprehensively evaluated their agronomic and socioeconomic trade-offs under consistent field conditions are limited. Here, a five-year field experiment on maize was conducted in Quzhou County, NCP, a global NH 3 emission hotspot and a major maize-producing region in China, to evaluate the effectiveness of six representative mitigation practices, including reducing N application rate (OU-SB), replacing urea with organic fertilizer (OR-SB), applying calcium ammonium nitrate (CAN-SB), controlled-release urea (CRU-SB), urease-inhibiting urea (UI-SB), and deep placement of urea (OU-DP). Conventional farmer practice (CU-SB) and a non-N control were also included as references. Compared with CU-SB, five of six mitigation treatments (except for OU-SB) significantly reduced NH 3 emissions by 47–74 % and yield-scaled NH 3 emission by 52–77 %, while maintaining or improving grain N content, plant N uptake, grain yield, and N use efficiencies. Implementing these practices across all maize areas in Quzhou could reduce NH 3 -N by 501–1431 t and generate US$2.15–5.66 million in social benefits, along with increased production benefits (except for OU-SB). Among those practices, CRU-SB, UI-SB, and CAN-SB were most effective, achieving the lowest cumulative NH 3 emissions (16.8–20.1 kg NH 3 -N ha −1 ) and yield-scaled emissions (1.7–1.9 g NH 3 -N kg −1 grain), thereby generating highest mitigation potential and social benefits in Quzhou maize, in addition to increased production benefits. Overall, CRU-SB is recommended for its superior greenhouse gas mitigation potential. These results highlight the potential role of optimized N management in reducing NH 3 emissions and generating social co-benefits in maize croplands, providing offer practical guidance for local farmers and policymakers. Although plot-based findings are promising, further validation at broader farm scales is required prior to regional implementation. • Five-year study assessed NH₃ mitigation strategies for maize in Quzhou County. • Optimized nitrogen practices reduced NH₃ emissions while maintaining crop yield. • NH₃ mitigations in Quzhou maize could reduce emissions by 501–1431 t N. • NH₃ mitigations yield social benefits valued at US$ 2.15–5.66 million.