Haoyu Qian, Zhengqi Yuan, Nana Chen, Xiangcheng Zhu, Shan Huang, Changying Lu, Kailou Liu, Feng Zhou, Pete Smith, Hanqin Tian, Qiang Xu, Jianwen Zou, Shuwei Liu, Zhenwei Song, Weijian Zhang, Songhan Wang, Zhenghui Liu, Ganghua Li, Ziyin Shang, Yanfeng Ding, Kees Jan van Groenigen, Yu Jiang

Nature Communications; 2025; IF:16.1

DOI: 10.1038/s41467-025-58090-0

Abstract

Agricultural soils contribute ~52% of global anthropogenic nitrous oxide (N₂O) emissions, predominantly from nitrogen (N) fertilizer use. Global N₂O emission factors (EFs), estimated using IPCC Tier 1 methodologies, largely rely on short-term field measurements that ignore legacy effects of historic N fertilization. Here we show, through data synthesis and experiments, that EFs increase over time. Historic N addition increases soil N availability, lowers soil pH, and stimulates the abundance of N₂O producing microorganisms and N₂O emissions in control plots, causing underestimates of EFs in short-term experiments. Accounting for this legacy effect, we estimate that global EFs and annual fertilizer-induced N₂O emissions of cropland are 1.9% and 2.1 Tg N₂O-N yr−1, respectively, both ~110% higher than IPCC estimates. Our findings highlight the significance of legacy effects on N₂O emissions, emphasize the importance of long-term experiments for accurate N₂O emission estimates, and underscore the need for mitigation practices to reduce N₂O emissions.