Soil microbial community dynamics mediate the priming effects caused by in situ decomposition of fresh plant residues

Guangcan Yu; Houben Zhao; Jie Chen; Tianlin Zhang; Zhanglin Cai; Guangyi Zhou; Zhaojia Li; Zhijun Qiu; Zhongmin Wu

doi:10.1016/j.scitotenv.2020.139708

Soil microbial community dynamics mediate the priming effects caused by in situ decomposition of fresh plant residues

Sci Total Environ. 2020 Oct 1:737:139708. doi: 10.1016/j.scitotenv.2020.139708. Epub 2020 May 27.

Authors

Guangcan Yu¹, Houben Zhao¹, Jie Chen¹, Tianlin Zhang¹, Zhanglin Cai¹, Guangyi Zhou¹, Zhaojia Li¹, Zhijun Qiu¹, Zhongmin Wu²

Affiliations

¹ Research Institute of Tropical Forestry, Chinese Academy of Forestry, Longdong, Guangzhou 510520, PR China.
² Research Institute of Tropical Forestry, Chinese Academy of Forestry, Longdong, Guangzhou 510520, PR China. Electronic address: ritfwzm@caf.ac.cn.

PMID: 32474301
DOI: 10.1016/j.scitotenv.2020.139708

Abstract

Extreme climate events always leave numerous fresh plant materials (FOM) in forests, thus increasing the input of carbon (C) resources to soil system. The input of exogenous C may accelerate or inhibit the decomposition of soil organic carbon (SOC), which is defined as the positive or negative priming effect (PE), respectively. However, the characteristics and microbial mechanisms of PE caused by FOM remain unknown. A 110-day in situ soil incubation experiment was conducted in a subtropical forest, with ¹³C-labeled fresh leaves from four native species (Castanopsis fissa, CF; Pinus massoniana, PM; Machilus chekiangensis, MC; and Castanopsis chinensis, CC) serving as the FOM respectively. We measured the CO₂ effluxes derived from ¹³C-labeled FOM and soil, and the composition and diversity of soil bacterial and fungal communities throughout the incubation to explore the correlations between PE and microbial attributes. As a result, the PE caused by FOM inputs were negative initially but became positive after 61 d. The FOM decomposition rate was positively related to PE intensity, and there was a significant difference between coniferous and broadleaved species in the middle period of the study. More than 77% of the total C lost from FOM was emitted as CO₂, indicating that FOM-C serves as an energy resource for soil microbes. The α-diversity of the bacterial community at genus-level showed significantly positive correlation with PE at 24 d, and the composition of bacterial community at OTU-level had a marked relationship with the PE between 24-110 d. The relationship between fungal community diversity and composition with PE was only observed at 7 and 110 d, respectively. This study firstly investigated the patterns of PE resulted from numerous FOM input, and the results suggested that soil bacterial community, in particular the Actinobacteria phyla, played a more important role in triggering such PEs than fungal community.

Keywords: Carbon cycling; Global climate change; Hypoxia; Isotope labeling; Litter decomposition; Microbial composition.

MeSH terms

Carbon
Forests
Microbiota*
Pinus*
Soil
Soil Microbiology

Substances

Soil
Carbon