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- Title
Fraction of CH oxidized in paddy field measured by stable carbon isotopes.
- Authors
Zhang, Guangbin; Zhang, Wenxuan; Yu, Haiyang; Ma, Jing; Xu, Hua; Yagi, Kazuyuki
- Abstract
Aims: Estimating the fraction of CH that is oxidized ( F) in paddy field using the stable carbon isotope natural abundance (SCINA) method and discussing the availabilities of δCH (newly produced δCH) and δCH (oxidized δCH) in the method. Methods: CH fluxes from a continuously flooded paddy field and via rice plants, CH concentrations in soil pore water and floodwater, CH production rates of soil slurries and rice roots, and their stable carbon isotopes ( δC) were measured during the rice growing season through field and incubation experiments. Results: The estimation of F in the rhizosphere was the most efficient by using anaerobically produced δCH of the soil as δCH and δCH emitted from the field minus transport fractionation factor ( ε = −12.82 ‰) as δCH. So, rhizospheric F was measured to be about 10-60 %, relatively high in the first half of the season. As porewater CH was potentially affected by CH oxidation and transport in field conditions, its δCH poorly represented δCH or δCH. However, porewater δCH was 10-22 ‰ lower than floodwater δCH, indicating that around 30-60 % of the CH was oxidized at the soil-water interface when porewater CH released into the atmosphere. Anaerobically produced CH was highly C-depleted than aerobically produced CH, F at the soil and root surfaces in lab conditions could be estimated when using the corresponding δCH as δCH and δCH, and it was about 5-50 % and almost 100 %, respectively. Conclusions: The use of δCH and δCH in estimating F in paddy field should be dependent on different CH-oxidizing zones in different conditions.
- Subjects
METHANE; OXIDATION; PADDY fields; STABLE isotopes; CARBON isotopes; RHIZOSPHERE; SOIL porosity; SOIL-Water Balance Model
- Publication
Plant & Soil, 2015, Vol 389, Issue 1/2, p349
- ISSN
0032-079X
- Publication type
Article
- DOI
10.1007/s11104-014-2365-5