Nature Communications (Mar 2025)

Legacy effects cause systematic underestimation of N2O emission factors

  • 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

DOI
https://doi.org/10.1038/s41467-025-58090-0
Journal volume & issue
Vol. 16, no. 1
pp. 1 – 11

Abstract

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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.