Exploring Sulfate as an Alternative Electron Acceptor

A Potential Strategy to Mitigate N2O Emissions in Upland Arable Soils.

verfasst von

Hyun Ho Lee, Hanbeen Kim, Ye Lim Park, Marcus A Horn, Jeongeun Kim, Jaehyun Lee, Sakae Toyoda, Jeongeun Yun, Hojeong Kang, Sang Yoon Kim, Jinho Ahn, Chang Oh Hong

Abstract

Agricultural activities are a significant source of nitrous oxide (N

2O), accounting for approximately 60% of global emissions, highlighting the urgent need for innovative strategies to mitigate N

2O emissions. Microbes conserve nearly as much energy with nitrate (NO

-) as oxygen (O

2) respiration under limited O

2 availability. Thus, microorganisms prioritize NO

-, limiting exploration of alternative electron acceptors (EAs) to inhibit N

2O emissions through NO

- respiration in upland arable soils. Current approaches remain insufficient, and the interactions between alternative EA reduction and pathways for N

2O emissions remain poorly understood. This study evaluated oxidized iron, manganese, and sulfate as alternative EAs to reduce N

2O emissions, along with the effects of zero-valent metals (ZVMs). Metal sulfates (MSs) significantly minimized N

2O emissions by inhibiting denitrification rather than altering nitrification in microcosms, as supported by isotope mapping and inorganic nitrogen concentrations. Among others, putative complete denitrifiers, N

2O reducers, and sulfate reducers were stimulated, whereas ZVMs stimulated N

2O emissions and 16S rRNA gene abundance. Moreover, the abundance of denitrifier-related genes (nirK, nirS, norB, and nosZ) consistently decreased under MS treatments, while dsrA mRNA abundance significantly increased. Sulfate (SO

2-) addition reshaped the soil microbial community by enriching sulfur-cycling taxa-including sulfate-reducing and sulfur-oxidizing bacteria-while suppressing nitrifiers such as Nitrospira, potentially disrupting nitrification-denitrification coupling. Ureibacillus thermosphaerius, harboring genes for denitrification and SO

2- reduction, increased under MS treatment. These shifts likely redirected electron flow toward SO

2- respiration, reducing NO

- utilization and contributing to N

2O mitigation. Field-based manipulation experiments over 2 years demonstrated the feasibility of MSs in upland arable soils, reducing yield-scaled N

2O emissions by 21.5% without compromising crop yields. A systematic literature review and meta-analysis revealed that SO

2- application mitigated N

2O emissions by an average of 9%, with over 70% of observations showing a decreasing trend, underscoring its potential as an effective soil amendment for sustainable agriculture.

Organisationseinheit(en)

Institut für Mikrobiologie

Externe Organisation(en)

University of British Columbia
Kyung Hee University
Seoul National University
Korea Institute of Science and Technology
Institute of Science Tokyo (Science Tokyo)
Pusan National University
Yonsei University
Sunchon National University

Typ

Artikel

Journal

Global change biology

Band

ISSN

1354-1013

Publikationsdatum

13.08.2025

Publikationsstatus

Veröffentlicht

Peer-reviewed

ASJC Scopus Sachgebiete

Globaler Wandel, Umweltchemie, Ökologie, Allgemeine Umweltwissenschaft

Elektronische Version(en)

https://doi.org/10.1111/gcb.70428 (Zugang: Offen)