Anaerobic oxidation of methane in paddy soil: Role of electron acceptors and fertilization in mitigating CH4 fluxes

Publication date: Available online 22 November 2019Source: Soil Biology and BiochemistryAuthor(s): Lichao Fan, Michaela A. Dippold, Tida Ge, Jinshui Wu, Volker Thiel, Yakov Kuzyakov, Maxim DorodnikovAbstractThe anaerobic oxidation of methane (AOM) in marine ecosystems is ubiquitous and largely coupled to sulfate reduction. In contrast, the role of AOM in terrestrial environments and the dominant electron acceptors driving terrestrial AOM needs deeper understanding. Submerged rice paddies with intensive CH4 production have a high potential for AOM, which can be important for greenhouse gas mitigation strategies. Here, we used 13CH4 to quantify the AOM rates in paddy soils under organic (Pig manure, Biochar) and mineral (NPK) fertilization. Alternative-to-oxygen electron acceptors for CH4 oxidation, including Fe3+, NO3−, SO42−, and humic acids, were examined and their potential for CH4 mitigation from rice paddies was assessed by 13CH4 oxidation to 13CO2 under anoxic conditions.During 84 days of anaerobic incubation, the cumulative AOM (13CH4-derived CO2) reached 0.15–1.3 μg C g-1 dry soil depending on fertilization. NO3- was the most effective electron acceptor, yielding an AOM rate of 0.80 ng C g-1 dry soil h-1 under Pig manure. The role of Fe3+ in AOM remained unclear, whereas SO42- inhibited AOM but strongly stimulated the production of unlabeled CO2, indicating intensive sulfate-induced decomposition of organic matter. Humic acids were the second most effective ...
Source: Soil Biology and Biochemistry - Category: Biology Source Type: research