Influence of drought intensity on soil carbon priming and its temperature sensitivity after rewetting

Rui Zhang; Rong Li; Jialiang Kuang; Zhenqing Shi

doi:10.1016/j.scitotenv.2023.168362

Influence of drought intensity on soil carbon priming and its temperature sensitivity after rewetting

Sci Total Environ. 2024 Jan 15:908:168362. doi: 10.1016/j.scitotenv.2023.168362. Epub 2023 Nov 7.

Authors

Rui Zhang¹, Rong Li², Jialiang Kuang¹, Zhenqing Shi¹

Affiliations

¹ School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China.
² School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China. Electronic address: lir@scut.edu.cn.

PMID: 37939946
DOI: 10.1016/j.scitotenv.2023.168362

Abstract

Global climate change can affect the soil thermal and moisture condition, potentially disrupting microbial-mediated soil respiration and altering the soil C cycle. However, the complex relationship between the soil C turnover and transient thermal and moisture conditions is not fully understood. Specifically, quantitative understanding is lacking regarding the impact of drought-rewetting events and temperature on the response of soil organic carbon (SOC) decomposition rate to exogenous C input, known as the priming effects (PEs). Herein, we quantified glucose-induced PEs during the rewetting of soils incubated under two drought intensities [with 20 % and 33 % water holding capacity (WHC)], at different incubation temperatures (15, 25, and 35 °C). Moreover, the effect size of drought intensities on PEs and the temperature sensitivity of PEs were quantified using lnRR (Response Ratio) and Q₁₀ of PEs. Glucose input triggered positive PEs after 21 d incubation and increased SOC decomposition by 29.7-72.7 %. Drought intensity showed positive effect (lnRR > 0) on PEs at lower temperatures (15 and 25 °C) but showed negative effect (lnRR < 0) on PEs at higher temperature (35 °C). At moderate drought intensity (33 % WHC) before rewetting, PEs increased significantly with incubation temperature (Q₁₀ = 1.65). Contrastingly, at high drought intensity (20 % WHC), temperature did not significantly influence PEs during the 21-d incubation after rewetting (Q₁₀ = 0.96). The combination of drought, temperature change and glucose addition significantly changed the abundances in the dominant bacterial phyla (Proteobacteria, Actinobacteria, and Chloroflexi) and fungal phylum (Ascomycota), which likely affect PEs. Furthermore, the decrease in the demand for microbial-driven N mining, which is a crucial factor in promoting positive PEs, was associated with drought intensity at high temperature (35 °C). Our study provided a quantitative and mechanistic understanding of the impact of drought intensity on PEs before rewetting and its temperature sensitivity.

Keywords: Bacterial and fungal composition; Birch effect; Microbial-driven nitrogen mining; Priming effect; Q(10); Response ratio.