The increasing age of facility agriculture significantly enriched microplastics and affected soil bacterial communities.

Microplastic (MP) pollution in facility agriculture is increasingly concerning, yet its interaction with soil properties and microbial communities remains unclear. This study analyzed soil samples from 10 agricultural facility bases in Beijing, revealing an average MP abundance of 1760 ± 868.02 items/kg. MP levels showed a positive correlation with facility age, with fragments (47.3 %), films (26.2 %), and fibres (21.6 %) as the dominant forms, primarily composed of polypropylene (33.5 %) and polyethylene (17.3 %). Both facility age and MPs significantly increased the abundance of the phylum Acidobacteriota and the genus Hyphomicrobium. Further analysis indicated that soil pH, organic matter content, and facility age exerted stronger effects on soil microbial communities than MPs, shaping their ecological functions through shifts in microbial composition. Functional analysis of microbial communities using the Functional Annotation of Prokaryotic Taxa (FAPROTAX) tool revealed that facility age significantly influenced microbial functions, negatively impacting carbon cycling while enhancing nitrogen cycling, whereas MP abundance showed relatively minor effects. These findings provide important insights into soil MP pollution and its implications for soil ecosystem health and sustainable agricultural development.