Abundance of microbial co2-fixing genes during the late rice season in a long-term management paddy field amended with straw and straw-derived biochar

Xizhi Huang, Cong Wang, Qiong Liu, Zhenke Zhu*, Tin M. Lynn, Jianlin Shen, Andrew S. Whiteley, Deepak Kumaresan, Tida Ge, Jinshui Wu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Straw return and biochar addition are promising approaches to enhance carbon sequestration and reduce greenhouse gas emission; however, their effect on CO2-fixing autotrophs remains unclear. Hence, quantitative PCR based on cbbL and cbbM, accC, and hcd, which are marker genes of the Calvin cycle, the 3-hydroxypropionate cycle, and the 4-hydroxybutyrate cycle, respectively, were used to determine the abundance of CO2-fixing autotrophs in paddy soil. Soils with chemical fertilizers receiving no exogenous carbon amendment, low and high amounts of rice straw, or low and high amounts of biochar were sampled at the tillering, milky, and ripening stages of late rice season. Results showed that both straw and biochar application increased the abundance of CO2-fixing microbes in paddy soil, whereas more abundant CO2-fixing microorganisms were observed in HS and LC rather than other treatments. The effects of different amounts of straw and biochar are attributable to the prominent differences in their properties. Redundancy analysis revealed that redox potential, C/N ratio of input fertilizer, and soil NO3 - -N content were significantly correlated with the gene abundance of CO2-fixing microorganisms. Path analysis revealed that gene abundance was causally and indirectly driven by rice growth stage and exogenous C addition. Collectively, our study suggested that adding extra carbon affected the growth of CO2-fixing microorganisms, which provided novel insights into the effect of straw return and biochar addition in paddy soil.

Original languageEnglish
Pages (from-to)306-316
JournalCanadian Journal of Soil Science
Issue number2
Publication statusPublished - 09 Mar 2018


  • Biochar amendment
  • Carbon dioxide fixation
  • Marker gene
  • Paddy soil
  • Straw return

ASJC Scopus subject areas

  • Soil Science


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