N<sub>2</sub>O Production and Reduction in Chinese Paddy Soils: Linking Microbial Functional Genes with Soil Chemical Properties
Nitrous oxide (N<sub>2</sub>O) emissions from paddy soils significantly contribute to global warming; however, the regulatory mechanisms of microbial denitrification remain poorly understood. This study investigated the biotic and abiotic drivers of N<sub>2</sub>O production...
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| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-06-01
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| Series: | Atmosphere |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4433/16/7/788 |
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| Summary: | Nitrous oxide (N<sub>2</sub>O) emissions from paddy soils significantly contribute to global warming; however, the regulatory mechanisms of microbial denitrification remain poorly understood. This study investigated the biotic and abiotic drivers of N<sub>2</sub>O production and reduction across seven paddy soils spanning China’s major rice-growing regions, using integrated qPCR, incubation experiments, and multivariate analyses. Results demonstrated niche partitioning among denitrifying microorganisms. Pearson correlation analysis demonstrated significant positive correlations between potential N<sub>2</sub>O production rates and the abundances of denitrification genes (<i>nirS</i>, <i>nirK</i>, and fungal <i>nirK</i>), as well as between N<sub>2</sub>O reduction rates and <i>nosZ</i> gene abundances (both clade I and II). Key soil chemical properties, including pH, total carbon (TC), and NH<sub>4</sub><sup>+</sup>-N content, showed significant relationships with both potential N<sub>2</sub>O production rates and reduction rates. Furthermore, random forest analysis identified <i>nirS,</i> fungal <i>nirK</i>, TC, and pH as key predictors of N<sub>2</sub>O production, while <i>nosZ</i> (clade I and II), TC, and pH governed N<sub>2</sub>O reduction. Structural equation modeling revealed that <i>nirS</i>-type bacteria predominantly drove N<sub>2</sub>O production, whereas <i>nosZ</i> II-encoded microorganisms primarily mediated N<sub>2</sub>O reduction. Moreover, TC exhibited direct positive effects on both processes, while pH indirectly influenced N<sub>2</sub>O production by regulating <i>nirS</i> abundance and affected reduction via <i>nosZ</i> Ⅱ modulation. These findings provide a mechanistic framework for mitigating agricultural denitrification-derived N<sub>2</sub>O emissions through a targeted management of soil carbon and pH conditions to optimize complete denitrification. |
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| ISSN: | 2073-4433 |