Pedosphere (3): 759--769, 2026
ISSN 1002-0160/CN 32-1315/P
©2026 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Noteworthy roles of autotrophic carbon fixation in a semiarid farmland soil |
Zicun ZHENG1,2, Zhen LIU3,5, Fang KANG1, Boyuan LIU1, Jing XU1, Xiang FANG1, Lang LIU1, Keyu FA1,3,4,5 |
1State Key Laboratory of Efficient Utilization of Agricultural Water Resources, China Agricultural University, Beijing 100083 (China);
2 Powerchina Zhongnan Engineering Corporation Limited, Changsha 410014 (China);
3 CAS Engineering Laboratory for Yellow River Delta Modern Agriculture, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China);
4 Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083 (China);
5 Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Wuzhong 751500 (China) |
| ABSTRACT |
| Autotrophs are widely distributed in soils of semiarid farmlands. However, due to limited research, the species and characteristics of the carbon (C) fixation capacity of photoautotrophs and chemoautotrophs remain poorly understood. This knowledge gap significantly hinders our understanding of farmland soil C dynamics and fixation potential. In this study, we identified the photoautotrophic and chemoautotrophic microbial species in a semiarid farmland soil and assessed their CO2 fixation capacity using metagenomics and in-situ 13CO2 tracing techniques. The results revealed that in the semiarid farmland soil, photoautotrophs (such as Chloroflexi bacterium CSP1-4 and Sphingomonas sp. URHD0057) and chemoautotrophs (such as Solirubrobacter sp. URHD0082 and Gaiella sp. SCGC AG-212-M14) accounted for approximately 13.6% and 86.4% of all autotrophs, respectively. Both photoautotrophs and chemoautotrophs were found to fix C at an overall rate of approximately 5.961 mg C m-2 d-1. Further analysis revealed that both autotrophs exhibited functional redundancy in C fixation, which may enhance their environmental adaptability. The unit abundance microbial C fixation rate of photoautotrophs was approximately 1.5 times that of chemoautotrophs. These findings underscore that atmospheric C transformation through photoautotrophs and chemoautotrophs occurs at a substantial rate in soils of semiarid farmlands, thereby broadening our understanding of C fixation characteristics and the ecological significance of soil autotrophs in semiarid farmland ecosystems. |
| Key Words: carbon fixation pathway|carbon fixation rate|chemoautotrophs|in-situ 13CO2 labeling|metagenomics|photoautotrophs |
| Citation: Zheng Z C, Liu Z, Kang F, Liu B Y, Xu J, Fang X, Liu L, Fa K Y. 2026. Noteworthy roles of autotrophic carbon fixation in a semiarid farmland soil. Pedosphere. 36(3): 759-769. |
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