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Nitrogen and phosphorus addition-induced soil and microbial ecological stoichiometry regulated carbon decomposition and accumulation and reduced soil carbon content in Tibetan alpine meadows
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  • Jin Hua Li,
  • Rui Zhang,
  • Bing Heng Cheng,
  • Lu Feng Ye,
  • Wenjin Li
Jin Hua Li
Lanzhou University
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Rui Zhang
Lanzhou University
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Bing Heng Cheng
Lanzhou University
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Lu Feng Ye
Lanzhou University
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Wenjin Li
State Key Laboratory of Grassland Agroecosystems, Lanzhou University
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Abstract

Nitrogen (N) and phosphorus (P) additions to grasslands increase aboveground plant biomass and modify plant community composition, thereby affect plant-derived organic carbon inputting to soil and soil C cycling and storage. However, the effects of nutrient additions on SOC decomposition and soil C sequestration have no census and their underlying mechanisms are poorly understood. This study aimed to explore the mechanisms underlying SOC decomposition and SOC content decline in the topsoil of Tibetan alpine meadows after nine-year field N and P additions. Soil and microbial stoichiometric characteristics were measured and priming effects (PEs), substrate decomposition, as well as microbial C use efficiency (CUE) by adding 13C labeled substrate (glucose or vanillin) were analyzed. N and P additions differentially affected the magnitude and direction of PEs and SOC decomposition, accelerated substrate mineralization of glucose by 33-45% and that of vanillin by 11-45%, but decreased microbial CUE of glucose by 9-15% and that of vanillin by 11-48%. This was associated with the N and P additions-induced lower soil ecological stoichiometric ratios and higher microbial C:N:P ratios compared with Control. Therefore, these comprehensive effects of N and P additions on decomposition of SOC and plant-derived C substrates reduced SOC sequestration and thus SOC content. Long-term N and P additions would weaken soil functioning as C pool of Tibetan alpine meadows.

Peer review status:ACCEPTED

26 Mar 2020Submitted to Land Degradation & Development
27 Mar 2020Submission Checks Completed
27 Mar 2020Assigned to Editor
19 Apr 2020Reviewer(s) Assigned
04 Jun 2020Review(s) Completed, Editorial Evaluation Pending
21 Jun 2020Editorial Decision: Revise Major
13 Jul 20201st Revision Received
13 Jul 2020Submission Checks Completed
13 Jul 2020Assigned to Editor
27 Aug 2020Review(s) Completed, Editorial Evaluation Pending
29 Sep 2020Editorial Decision: Accept