EGU21-9088
https://doi.org/10.5194/egusphere-egu21-9088
EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Alternating wet-dry cycles rather than sulfate fertilization control pathways of methanogenesis and methane turnover in rice straw-amended paddy soil

Qiong Liu1, Marco Romani2, Jiajia Wang3, Britta Planer-Friedrich3, Johanna Pausch1, and Maxim Dorodnikov4,5
Qiong Liu et al.
  • 1University of Bayreuth, Agroecology, Germany (qiong.liu@uni-bayreuth.de)
  • 2Rice Research Centre, Ente Nazionale Risi, Castello d’Agogna, Italy
  • 3Environmental Geochemistry, BayCEER, University of Bayreuth, Germany
  • 4Soil Science of Temperate Ecosystems, Georg-August University of Göttingen, Germany
  • 5Biogeochemistry of Agroecosystems, Georg-August University of Göttingen, Germany

Alternate wet-drying (AWD) and sulfate fertilization have been considered as effective management practices for lowering CH4 emissions from paddy soils. However, the effects of management practices on in situ belowground CH4 turnover (production and oxidation) are not yet fully understood. Here, soil CO2 and CH4 concentrations and their C isotope compositions were measured at three rice growing stages in straw-amended paddy soils with and without sulfate fertilization under continuously flooded conditions and two wet-dry-cycles. CH4 concentration reached 51.0 mg C L-1 at flowering stage under flooded conditions, while it decreased to 0.04 mg C L-1 under AWD. Relative enrichment of δ13C in CH4 and depletion of δ13C in CO2 under AWD indicated CH4 oxidation. Sulfate addition had no significant effect on CH4 concentration. The ample substrate supply might have prevented sulfate-reducing bacteria from out-competing methanogenic archaea and could therefore explain the absence of a fall in CH4 production. The δ13C-CO2 enrichment over time (7 ‰ and 5‰ with and without sulfate fertilizer, respectively) under flooded conditions likely indicates an increasing contribution of hydrogenotrophic methanogenesis to CH4 production with ongoing rice growth. Overall, the results showed that AWD could more efficiently reduce CH4 production than sulfate fertilization in rice-straw-amended paddy soils.

 

How to cite: Liu, Q., Romani, M., Wang, J., Planer-Friedrich, B., Pausch, J., and Dorodnikov, M.: Alternating wet-dry cycles rather than sulfate fertilization control pathways of methanogenesis and methane turnover in rice straw-amended paddy soil, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9088, https://doi.org/10.5194/egusphere-egu21-9088, 2021.

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