Preprints
https://doi.org/10.5194/egusphere-2025-1122
https://doi.org/10.5194/egusphere-2025-1122
20 Mar 2025
 | 20 Mar 2025

Contribution of soil Microbial Necromass Carbon to Soil Organic Carbon fractions and its influencing factors in different grassland types

Shenggang Chen, Yaqi Zhang, Jun Ma, Mingyue Bai, Jinxiao Long, Ming Liu, Yinglong Chen, Jianbin Guo, and Lin Chen

Abstract. Microbial necromass carbon(MNC) is a significant source of soil organic carbon (SOC), the quantitative contribution of MNC to distinct SOC fractions and its regulatory mechanisms across various grassland types remain largely unexplored. This study through a comprehensive investigation of soil profiles (0–20 cm, 20–40 cm, and 40–100 cm) across four grassland types in Ningxia, China, encompassing meadow steppe (MS), typical steppe (TS), desert steppe (DS), and steppe desert (SD). We quantified mineral-associated organic carbon (MAOC), particulate organic carbon (POC), and their respective microbial necromass components, including total microbial necromass carbon (TNC), fungal necromass carbon (FNC), and bacterial necromass carbon (BNC), and analyzed the contributions to SOC fractions and influencing factors. Our findings reveal three key insights. First, the contents of MAOC and POC in the 0–100 cm soil layer were in the following order of magnitude: Meadow steppe (MS) >Typical steppe (TS) > Desert steppe (DS) > Steppe desert (SD), with the average content of POC was 9.3 g/kg, which was higher than the average content of MAOC (8.73 g/kg). Second, the content of microbial TNC in MAOC and POC decreased with the depth of the soil layer, the average content of FNC was 3.02 g/kg and 3.85 g/kg, which was higher than the average content of BNC (1.64 g/kg and 2.08 g/kg). FNC dominated both MAOC and POC, and its contribution was higher than the contribution of BNC. Thid, through regression analysis and random forest modeling, we identified key environmental drivers of MNC dynamics: mean annual rainfall (MAP), electrical conductance (EC), and soil total nitrogen(TN) emerged as primary regulators in surface soils (0–20cm), while available potassium(AK), SOC, and mean annual temperature (MAT) dominated deeper soil layers (20–100 cm). This research by: 1) establishing the vertical distribution patterns of MNC and SOC fractions in soil profiles; 2) quantifying the relative contributions of MNC to SOC fractions across different grassland ecosystems soil profiles and elucidating their environmental controls, offering a deeper understanding of the mechanisms driving MNC to soc fractions accumulation in diverse grassland ecosystems, and provide data support for further research on the microbiological mechanisms of soil organic carbon formation and accumulation in arid and semi-arid regions.

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Journal article(s) based on this preprint

22 Oct 2025
Contribution of soil microbial necromass carbon to soil organic carbon fractions and its influencing factors in different grassland types
Shenggang Chen, Yaqi Zhang, Jun Ma, Mingyue Bai, Jinxiao Long, Ming Liu, Yinglong Chen, Jianbin Guo, and Lin Chen
SOIL, 11, 883–898, https://doi.org/10.5194/soil-11-883-2025,https://doi.org/10.5194/soil-11-883-2025, 2025
Short summary
Shenggang Chen, Yaqi Zhang, Jun Ma, Mingyue Bai, Jinxiao Long, Ming Liu, Yinglong Chen, Jianbin Guo, and Lin Chen

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2025-1122', Anonymous Referee #1, 04 May 2025
    • AC1: 'Reply on RC1', Jianbing Guo, 14 May 2025
  • RC2: 'Comment on egusphere-2025-1122', Anonymous Referee #2, 13 May 2025
    • AC2: 'Reply on RC2', Jianbing Guo, 29 May 2025
    • AC3: 'Reply on RC2', Jianbing Guo, 29 May 2025

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2025-1122', Anonymous Referee #1, 04 May 2025
    • AC1: 'Reply on RC1', Jianbing Guo, 14 May 2025
  • RC2: 'Comment on egusphere-2025-1122', Anonymous Referee #2, 13 May 2025
    • AC2: 'Reply on RC2', Jianbing Guo, 29 May 2025
    • AC3: 'Reply on RC2', Jianbing Guo, 29 May 2025

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
ED: Publish subject to minor revisions (review by editor) (30 May 2025) by Ashish Malik
AR by Jianbing Guo on behalf of the Authors (04 Jun 2025)  Author's response   Author's tracked changes   Manuscript 
ED: Publish subject to revisions (further review by editor and referees) (03 Jul 2025) by Ashish Malik
AR by Jianbing Guo on behalf of the Authors (03 Jul 2025)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (16 Jul 2025) by Ashish Malik
RR by Anonymous Referee #2 (23 Aug 2025)
ED: Publish subject to technical corrections (03 Sep 2025) by Ashish Malik
ED: Publish subject to technical corrections (03 Sep 2025) by Rémi Cardinael (Executive editor)
AR by Jianbing Guo on behalf of the Authors (05 Sep 2025)  Author's response   Manuscript 

Journal article(s) based on this preprint

22 Oct 2025
Contribution of soil microbial necromass carbon to soil organic carbon fractions and its influencing factors in different grassland types
Shenggang Chen, Yaqi Zhang, Jun Ma, Mingyue Bai, Jinxiao Long, Ming Liu, Yinglong Chen, Jianbin Guo, and Lin Chen
SOIL, 11, 883–898, https://doi.org/10.5194/soil-11-883-2025,https://doi.org/10.5194/soil-11-883-2025, 2025
Short summary
Shenggang Chen, Yaqi Zhang, Jun Ma, Mingyue Bai, Jinxiao Long, Ming Liu, Yinglong Chen, Jianbin Guo, and Lin Chen
Shenggang Chen, Yaqi Zhang, Jun Ma, Mingyue Bai, Jinxiao Long, Ming Liu, Yinglong Chen, Jianbin Guo, and Lin Chen

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Latest update: 27 Oct 2025
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Short summary
Fungal necromass carbon (FNC) contribution to mineral-associated organic carbon (MAOC) and particulate organic carbon (POC) was higher than bacterial necromass carbon (BNC). In 0–20 cm, FNC and BNC contributed more to MAOC, their contributions shifted toward POC in 20–100 cm. Microbial necromass carbon was affected by total nitrogen, mean annual rainfall, and electrical conductance in 0–20, while affected by available potassium, SOC, and mean annual temperature in 20–100.
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