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- Title
Not all soil carbon is created equal: Labile and stable pools under nitrogen input.
- Authors
Zang, Huadong; Mehmood, Imran; Kuzyakov, Yakov; Jia, Rong; Gui, Heng; Blagodatskaya, Evgenia; Xu, Xingliang; Smith, Pete; Chen, Haiqing; Zeng, Zhaohai; Fan, Mingsheng
- Abstract
Anthropogenic activities have raised nitrogen (N) input worldwide with profound implications for soil carbon (C) cycling in ecosystems. The specific impacts of N input on soil organic matter (SOM) pools differing in microbial availability remain debatable. For the first time, we used a much‐improved approach by effectively combining the 13C natural abundance in SOM with 21 years of C3–C4 vegetation conversion and long‐term incubation. This allows to distinguish the impact of N input on SOM pools with various turnover times. We found that N input reduced the mineralization of all SOM pools, with labile pools having greater sensitivity to N than stable ones. The suppression in SOM mineralization was notably higher in the very labile pool (18%–52%) than the labile and stable (11%–47%) and the very stable pool (3%–21%) compared to that in the unfertilized control soil. The very labile C pool made a strong contribution (up to 60%) to total CO2 release and also contributed to 74%–96% of suppressed CO2 with N input. This suppression of SOM mineralization by N was initially attributed to the decreased microbial biomass and soil functions. Over the long‐term, the shift in bacterial community toward Proteobacteria and reduction in functional genes for labile C degradation were the primary drivers. In conclusion, the higher the availability of the SOM pools, the stronger the suppression of their mineralization by N input. Labile SOM pools are highly sensitive to N availability and may hold a greater potential for C sequestration under N input at global scale.
- Subjects
CARBON in soils; MICROBIAL communities; MINERALIZATION; BIOMASS; ORGANIC compounds
- Publication
Global Change Biology, 2024, Vol 30, Issue 7, p1
- ISSN
1354-1013
- Publication type
Article
- DOI
10.1111/gcb.17405