Gross Ecosystem Productivity Dominates the Control of Ecosystem Methane Flux in Rice Paddies

Land

Changhui Peng¹  Haiqiang Guo²  Bin Zhao²  Min Zhao³  Qing Wang³  Hong Li⁴ 

[1] Department of Biology Science, Institute of Environment Sciences, University of Quebec at Montreal, Montreal, QC C3H 3P8, Canada;Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Coastal Ecosystems Research Station of the Yangtze River Estuary, Fudan University, Shanghai 200433, China;Shanghai Academy of Environmental Sciences, Shanghai 200233, China;State Key Laboratory of Coal Mine Disaster Dynamics and Control, Faculty of Architecture and Urban Planning, Chongqing University, Chongqing 400045, China;

关键词: CH₄ flux;    eddy covariance;    budget;    gross ecosystem productivity;    rice paddy;   

DOI  :  10.3390/land10111186

来源: DOAJ

【 摘 要 】

Although rice paddy fields are one of the world’s largest anthropogenic sources of methane CH₄, the budget of ecosystem CH₄ and its’ controls in rice paddies remain unclear. Here, we analyze seasonal dynamics of direct ecosystem-scale measurements of CH₄ flux in a rice-wheat rotation agroecosystem over 3 consecutive years. Results showed that the averaged CO₂ uptakes and CH₄ 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⁻²) and a GHG (averaged 174.38 g CO₂eq m⁻²) source except for a GHG sink in one year (2016) with a very high rice seeding density. While the linear correlation between daily CH₄ fluxes and gross ecosystem productivity (GEP) was not significant for the whole rice season, daily CH₄ fluxes were significantly correlated to daily GEP both before (R²: 0.52–0.83) and after the mid-season drainage (R²: 0.71–0.79). Furthermore, the F 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 CH₄ fluxes and GEP shifted between rice growth stages. This study highlights that GEP is a good predictor of daily CH₄ fluxes in rice paddies.

【 授权许可】

Unknown