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Assessment of depth-dependent microbial carbon use efficiency in long-term fertilized paddy soil using an 18O-H2O approach
  • +6
  • Mostafa Zhran,
  • Tida Ge,
  • Yaoyao Tong,
  • Yangwu Deng,
  • Xiaomeng Wei,
  • Lynn Tin MarOrcid,
  • Zhenke Zhu,
  • Jinshui Wu,
  • Anna Gunina
Mostafa Zhran
Egyptian Atomic Energy Authority
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Tida Ge
Institude of Subtropical Agriculture, The Chinese Academy of Sciences
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Yaoyao Tong
JiangXi University of Science and Technology
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Yangwu Deng
JiangXi University of Science and Technology
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Xiaomeng Wei
Institute of Subtropical Agriculture Chinese Academy of Sciences
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Lynn Tin Mar
Orcid
Institute of Subtropical Agriculture Chinese Academy of Sciences
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Zhenke Zhu
Institude of Subtropical Agriculture, The Chinese Academy of Sciences
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Jinshui Wu
Chinese Acad Sci
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Anna Gunina
Universitat Kassel
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Peer review status:ACCEPTED

10 Feb 2020Submitted to Land Degradation & Development
11 Feb 2020Submission Checks Completed
11 Feb 2020Assigned to Editor
13 Feb 2020Reviewer(s) Assigned
02 Mar 2020Peer Review Completed
13 Apr 2020Editorial Decision: Revise Major
11 May 20201st Revision Received
12 May 2020Assigned to Editor
12 May 2020Submission Checks Completed
05 Jun 2020Peer Review Completed
06 Jun 2020Editorial Decision: Revise Minor
13 Jun 20202nd Revision Received
15 Jun 2020Submission Checks Completed
15 Jun 2020Assigned to Editor
15 Jun 2020Peer Review Completed
20 Jun 2020Editorial Decision: Revise Minor
22 Jun 20203rd Revision Received
22 Jun 2020Submission Checks Completed
22 Jun 2020Assigned to Editor
22 Jun 2020Peer Review Completed
26 Jun 2020Editorial Decision: Accept

Abstract

Microbial biomass (MB) production and turnover strongly affect soil organic carbon (SOC) accumulation. Microbial carbon use efficiency (CUE) and MB turnover in paddy soil were determined using a novel substrate-independent H218O labeling approach and the effect of long-term fertilization with mineral (NPK) or combined (NPK+OM (manure)) amendments in 0-10, 10-20, and 20-30 cm depths were investigated. Long-term fertilization increased microbial C uptake, CUE, and growth rates, and all indexes were the highest in the NPK+OM treatment. The CUE ranged between 0.07 and 0.23 and showed variable behavior with depth: it reduced in the control treatment, indicating that more C was allocated to energy production than biomass growth, and increased in fertilized soils, showing the shift of C usage for biomass growth. The highest CUE was observed at 20-30 cm in NPK and NPK+OM and indicated that microorganisms overcome the nutrient deficiency in deep soil layers by keeping high C uptake rates at a constant CUE. MBC turnover was more rapid in NPK (10-70 d) and NPK+OM (40-65 d) compared to control (80 d) and intensified with the depth. These findings highlight that under long-term fertilization MB turnover can be controlled by CUE. These shifts in the strategies of microorganisms functioning can explain the accumulation of SOC in heavily fertilized paddy soils.