Work

Nitrifier denitrification contributes substantially to nitrous oxide production in calcareous farmland soils

Year: 2026

Type: article

Abstract: Intensively managed agricultural soils are a major source of nitrous oxide (N₂O) emissions, yet the N₂O production pathways in calcareous soils remain unclear. Using sterilization assays, 15 N 18 O tracing, and qPCR analysis, we quantified the contributions of abiotic and microbial processes to N₂O production in calcareous farmland soils under long-term plastic film mulching and varying nitrogen (N) fertilization regimes. The results showed that abiotic contributions to N₂O production were negligible (<4%), but these contributions were higher in the no-N control than in the N-fertilized soils. Among microbial pathways, nitrifier denitrification (ND) dominated total N 2 O production (13.9–93.2%), followed by nitrifier nitrification (NN) and nitrification-coupled denitrification (NCD), with heterotrophic denitrification (HD) being minor (<13.5%). Long-term film mulching significantly reduced N₂O productions, accompanied by decreased potential nitrification rate (PNR), denitrification enzyme activity (DEA), and functional gene abundances (AOB amoA , nirK , and ( nirK + nirS )/ nosZ ratio), but maintained the dominant N₂O production pathways.Under film mulching, N fertilization significantly increased the contributions of ND and NCD while reducing those of NN and HD relative to the no N control, though no significant differences were observed among the N-fertilization regimes (moderate N rate-F 225 , high N rate-F 380 , moderate N plus manure-F 225+M ). N₂O fluxes strongly correlated ( p < 0.01) with NN, ND, NCD, soil TN, SOC, DON, NO₃ − , and microbial parameters (AOB amoA , nosZ , PNR, DEA). These findings indicate the predominance of ND in the studied calcareous farmland soils and reveal how agricultural practices regulate N₂O production at both process and molecular levels, providing insights for targeted mitigation strategies.

Source: Applied Soil Ecology

DOI: 10.1016/j.apsoil.2026.106867

Authors: Na Gao, Zifan Wang, Hongguang Pang, Lei Li, Yue Zhang, Dawei Chen

Institutions: Shijiazhuang University, Hebei Normal University, Northwest Normal University

Language: English

Topic: Soil Carbon and Nitrogen Dynamics

Subfield: Soil Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDGs: Zero hunger, Climate action, Life on land

Open Access status: hybrid

Estimated APC paid: $4,320