Earthworms mitigate drought effects on microbial decomposition of straw under varying microplastic conditions

Chuanxiong Huang; Weijie Zhao; Hangle Ren; Rui Wu; Ying Liu; Hongxin Xu; Benhua Sun; Jianglan Shi; Xiaohong Tian; Rui Yin

doi:10.1016/j.jhazmat.2025.139108

Earthworms mitigate drought effects on microbial decomposition of straw under varying microplastic conditions

J Hazard Mater. 2025 Jun 30:495:139108. doi: 10.1016/j.jhazmat.2025.139108. Online ahead of print.

Authors

Affiliations

¹ Key Laboratory of Low-Carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Northwest A & F University, Yangling 712100, China.
² Key Laboratory of Low-Carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Northwest A & F University, Yangling 712100, China. Electronic address: txhong@nwafu.edu.cn.
³ Key Laboratory of Low-Carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Northwest A & F University, Yangling 712100, China. Electronic address: rui.yin@nwafu.edu.cn.

PMID: 40602124
DOI: 10.1016/j.jhazmat.2025.139108

Abstract

Microplastic pollution and drought stress potentially threaten soil functions (e.g., straw decomposition) in semi-arid agroecosystems of the Loess Plateau. large decomposers (e.g., earthworms) can promote straw decomposition by modulating soil physico-chemical properties and microbial communities. However, whether, how, and to what extent earthworms can mitigate these negative effects. Here, we conducted a microcosm experiment to test the effects of microplastic pollution (no microplastic addition vs. biodegradable microplastic vs. non-degradable microplastic), and drought stress (ambient vs. drought) on microbial decomposition of straw in the presence vs. absence of earthworms. We found that both biodegradable and non-degradable microplastics enhanced microbial decomposition of straw by 11 % and 29 %, respectively, by boosting microbial diversity and total biomass. Drought, conversely, reduced microbial decomposition by 30 %. Notably, earthworms mitigated drought effects by promoting microbial decomposition by 22 % through increasing soil carbon and nutrient availability, as well as microbial biodiversity and biomass. Overall, these findings suggest that large soil decomposers can substantially alleviate the detrimental effects of global changes on ecosystem functions by enhancing the community complexity of small detritivores.

Keywords: Drought stress; Earthworms; Microplastic pollution; Soil microorganisms; Straw decomposition.