Effects of litter and root inputs on soil CH4 uptake rates and associated microbial abundances in natural temperature subalpine forests

Jia Xiong; Genxu Wang; Xiangyang Sun; Zhaoyong Hu; Yang Li; Juying Sun; Wei Zhang; Shouqin Sun

doi:10.1016/j.scitotenv.2023.168730

Effects of litter and root inputs on soil CH₄ uptake rates and associated microbial abundances in natural temperature subalpine forests

Sci Total Environ. 2024 Feb 20:912:168730. doi: 10.1016/j.scitotenv.2023.168730. Epub 2023 Nov 24.

Authors

Jia Xiong¹, Genxu Wang², Xiangyang Sun², Zhaoyong Hu², Yang Li², Juying Sun², Wei Zhang³, Shouqin Sun⁴

Affiliations

¹ Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China.
² State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China.
³ School of Agriculture, Forestry and Food Engineering, Yibin University, Yibin 644000, China.
⁴ State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China. Electronic address: shouqinsun@scu.edu.cn.

PMID: 38007118
DOI: 10.1016/j.scitotenv.2023.168730

Abstract

Climate change altered the quantities of aboveground plant litter and root inputs, but the effects on soil CH₄ uptake rates and underlying mechanisms remain unclear. To investigate these factors, a three-year detritus input and removal treatment (DIRT) study including six treatments (namely, CK, control; NL, litter removal; DL, double litter; NR, root exclusion; NRNL, root exclusion plus litter removal; and NRDL, root exclusion plus double litter) was conducted in broadleaf and coniferous forest subalpine forest ecosystems. The results showed that both the subalpine forest soils acted as sink for atmospheric CH₄ across all treatments, while the broadleaf forest had consistently higher CH₄ uptake rates than the coniferous forest. Based on the annual mean values, root exclusion (NR, NRNL and NRDL) significantly decreased soil CH₄ uptake rates by 35.9 %, 31.0 % and 43.4 % in the broadleaf forest and 36.7 %, 31.9 % and 40.6 % in the coniferous forest compared with CK treatments, respectively. Meanwhile, the mean soil CH₄ uptake rates were significantly reduced by 23.6 % and 17.3 % in the broadleaf forest and the coniferous forest under the DL treatments, respectively; nevertheless, the NL treatment significantly increased soil CH₄ uptake rates by 19.68 % and 14.4 %, respectively. The results clearly demonstrated that root exclusion exerted a greater influence on soil CH₄ uptake rates than plant litter manipulations. Correlation and redundancy analysis (RDA) revealed that the separation of root exclusion treatments from aboveground plant litter manipulations was based on higher soil water content, NH₄⁺-N and NO₃^--N concentrations, and lower DOC (dissolved organic carbon) concentrations and methanotroph pmoA gene abundance. The results suggest that future alterations in aboveground plant litter and root input, particularly a reduction in root input, can exert a stronger influence on regulating soil CH₄ uptake than aboveground litter manipulations in subalpine forests with cold and humid climatic conditions in response to future climate scenarios.

Keywords: Detritus input manipulations; Methanogen; Methanotroph; Soil CH(4) uptake rates; Subalpine forests.

MeSH terms

Ecosystem
Forests
Plants
Soil* / chemistry
Temperature
Tracheophyta*

Substances

Soil