Plant-mediated methane and nitrous oxide fluxes from a carex meadow in Poyang Lake during drawdown periods

• Published in: Plant and soil Vol. 400; no. 1-2; pp. 367 - 380
• Main Authors: Hu, Qiwu, Cai, Jiayan, Yao, Bo, Wu, Qin, Wang, Yeqiao, Xu, Xingliang
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.03.2016; Springer; Springer Nature B.V
• Subjects: aboveground biomass; Biomass; Biomedical and Life Sciences; Carbon dioxide emissions; Carex; Drawdown; Drying; Ecology; ecosystems; Emissions; Environmental aspects; Grassland soils; greenhouse gas emissions; Greenhouse gases; In situ measurement; Lakes; Lentic systems; Life Sciences; littoral zone; Littoral zones; Meadows; Methane; Nitrous oxide; Plant biomass; Plant Physiology; Plant roots; Plant Sciences; Regular Article; Roots; Shoots; Soil moisture; Soil Science & Conservation; soil water; temperature; Wetland soils; Wetlands; China; Poyang Lake; Subtropical; CH; Poyang Lake; meadow; N; O
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-015-2733-9

AIMS: Plants have been suggested to have significant effects on methane (CH₄) and nitrous oxide (N₂O) fluxes from littoral wetlands, but it remains unclear in subtropical lakes. METHODS: We conducted in situ measurement of CH₄ and N₂O fluxes for two years. To distinguish between the effects of shoots and roots, three treatments (i.e., intact plants as control, shoot clipping, and root exclusion) were used. Effects of plant biomass, temperature, and soil moisture on CH₄ and N₂O fluxes were analyzed. RESULTS: The mean ecosystem CH₄ emission rate was 36 μg CH₄ m⁻² h⁻¹ for drying periods, but 8219 μg CH₄ m⁻² h⁻¹ for drying-wetting transition periods. CH₄ fluxes were positively correlated with below-ground and total biomass, but not with above-ground biomass. Clipping did not significantly alter CH₄ flux rate, but root exclusion decreased the CH₄ flux by 116 % as compared to the control. N₂O emissions were similar for both the drying and drying-wetting transition periods, with a mean rate of 20 μg N₂O m⁻² h⁻¹. Both clipping and root exclusion significantly increased N₂O fluxes as compared to the control. CONCLUSIONS: There was no significant correlation between CH₄ and N₂O fluxes. Roots dominated plant-mediated enhancement in CH₄ fluxes, but played almost an equal role as shoots in plant-regulated suppression on N₂O fluxes in this Carex meadow during drawdown periods.