Gross Ecosystem Productivity Dominates the Control of Ecosystem Methane Flux in Rice Paddies
Although rice paddy fields are one of the world’s largest anthropogenic sources of methane CH<sub>4</sub>, the budget of ecosystem CH<sub>4</sub> and its’ controls in rice paddies remain unclear. Here, we analyze seasonal dynamics of direct ecosystem-scale measurements of CH&...
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| Autores principales: | , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/d82fd9091aa84b2ebd0310359b6ad993 |
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| Sumario: | Although rice paddy fields are one of the world’s largest anthropogenic sources of methane CH<sub>4</sub>, the budget of ecosystem CH<sub>4</sub> and its’ controls in rice paddies remain unclear. Here, we analyze seasonal dynamics of direct ecosystem-scale measurements of CH<sub>4</sub> flux in a rice-wheat rotation agroecosystem over 3 consecutive years. Results showed that the averaged CO<sub>2</sub> uptakes and CH<sub>4</sub> emissions in rice seasons were 2.2 and 20.9 folds of the wheat seasons, respectively. In sum, the wheat-rice rotation agroecosystem acted as a large net C sink (averaged 460.79 g C m<sup>−2</sup>) and a GHG (averaged 174.38 g CO<sub>2</sub>eq m<sup>−2</sup>) source except for a GHG sink in one year (2016) with a very high rice seeding density. While the linear correlation between daily CH<sub>4</sub> fluxes and gross ecosystem productivity (GEP) was not significant for the whole rice season, daily CH<sub>4</sub> fluxes were significantly correlated to daily GEP both before (R<sup>2</sup>: 0.52–0.83) and after the mid-season drainage (R<sup>2</sup>: 0.71–0.79). Furthermore, the <i>F</i> partial test showed that GEP was much greater than that of any other variable including soil temperature for the rice season in each year. Meanwhile, the parameters of the best-fit functions between daily CH<sub>4</sub> fluxes and GEP shifted between rice growth stages. This study highlights that GEP is a good predictor of daily CH<sub>4</sub> fluxes in rice paddies. |
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