Efficiency of 3,4-Dimethylpyrazole Phosphate in Mitigating N<sub>2</sub>O Emission Varied with Irrigation Regime in Drip-Irrigated Wheat Field
Agricultural soils are major anthropogenic sources of N<sub>2</sub>O emissions. The application of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) has been proved to be an effective management measure to mitigate N<sub>2</sub>O emissions. However, the influence...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Agronomy |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4395/14/12/3052 |
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| Summary: | Agricultural soils are major anthropogenic sources of N<sub>2</sub>O emissions. The application of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) has been proved to be an effective management measure to mitigate N<sub>2</sub>O emissions. However, the influence mechanism of DMPP on the mitigation of soil N<sub>2</sub>O emissions under different irrigation regimes remains unclear. Therefore, a lysimeter experiment was conducted to study the effects of irrigation level (lower irrigation limits of 75%, 65%, and 55% of field capacity (FC), signed as WH, WM, and WL) and DMPP addition (0% and 1% of N application, signed as D0 and D1) on N<sub>2</sub>O emissions, soil environmental factors such as ammonium nitrogen (NH<sub>4</sub><sup>+</sup>-N), nitrate nitrogen (NO<sub>3</sub><sup>−</sup>-N), water-filled pore space (WFPS), soil temperature, and the abundances of N<sub>2</sub>O-related genes (AOA <i>amoA</i>, AOB <i>amoA</i>, nirS, and nirK). The results showed that soil N<sub>2</sub>O emissions increased with the increasing of irrigation level. The efficiency of DMPP mitigating N<sub>2</sub>O emissions varies depending on irrigation regime. Compared to D0, D1 strongly decreased cumulative N<sub>2</sub>O emissions by 11.27%, 18.96%, and 15.05% in the WL, WM, and WH conditions, respectively. Meanwhile, D1 caused an obvious reduction in the AOB <i>amoA</i> gene by 29.73%, 47.02%, and 22.41%, respectively, but there was no significant effect on the AOA <i>amoA</i> gene. D1 was effective in decreasing nirS and nirK genes except in the WL condition; the percentages of reduction were 48.45%, 40.84% and 37.18%, 44.97% in the WM and WH conditions, respectively. In addition, D1 caused an increase in NH<sub>4</sub><sup>+</sup>-N content and a decrease in NO<sub>3</sub><sup>−</sup>-N content, WFPS, and soil temperature in all irrigation regimes. A higher significant correlation was observed between N<sub>2</sub>O emissions and NH<sub>4</sub><sup>+</sup>-N and AOB <i>amoA</i> in the WL and WM conditions, while a significant correlation was observed between N<sub>2</sub>O emissions and NO<sub>3</sub><sup>−</sup>-N, nirK, and nirS in the WH condition. It was revealed that with the increase in irrigation level, the main source of N<sub>2</sub>O emissions might change from nitrification to denitrification. Overall, our study indicated that in the WL and WM conditions, the mitigation of N<sub>2</sub>O emissions by DMPP was primarily attributable to the inhibition of the AOB <i>amoA</i> gene, whereas the inhibition of nirS and nirK genes was likely the dominant mechanism in the WH condition. The findings of this study will provide a theoretical basis for the application of a nitrification inhibitor for drip-irrigated winter wheat fields in the North China Plain. |
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| ISSN: | 2073-4395 |