期刊
SCIENCE OF THE TOTAL ENVIRONMENT
卷 748, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.scitotenv.2020.141318
关键词
Particulate organic carbon; Mineral-associated organic carbon; Nitrogen addition; Microbial biomass; Microbial residues
资金
- National Natural Science Foundation of China [31988102]
- CAS Interdisciplinary Innovation Team
Numerous studies have investigated the impact of nitrogen (N) addition on ecosystem carbon (C) storage and cycling. However, how N addition regulates the dynamics of different soil organic carbon (SOC) fractions and the underlying microbial mechanisms remain unclear. In this study, we assessed microbial controls (through biomass, residues and enzymes) of different SOC fractions (particulate organic carbon, POC and mineral-associated organic carbon, MAOC) in response to six years of N addition (50 kg N ha(-1) yr(-1)) in two temperate forests (Betula platyphylla vs. Quercus wutaishanica) in Northern China. Plant inputs (root biomass and leaf litterfall) and soil chemistry (pH, extractable inorganic N, and exchangeable cations) were unaltered by N addition in both forests. In the Q. wutaishanica forest, microbial biomass, residues, and enzymes were not sensitive to N addition, which may explain the lack of response in SOC and two fractions (POC and MAOC). However, in the B. platyphylla forest, although microbial biomass and enzymes as well as SOC and POC did not significantly change after N addition, both microbial residues (amino sugars) and MAOC significantly increased after N addition. Moreover, there was a strong positive correlation between microbial residues and MAOC pool within or across the Iwo forests. Collectively, these results suggest that the dynamics of microbial residues play a crucial role in controlling the response of mineral-associated SOC to N addition in these two forests. Separating bulk soil into distinct functional pools and considering microbial residues should help reveal the nuanced response of soil C dynamics under N addition. (C) 2020 Elsevier B.V. All rights reserved.
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