Effects of plastic mulch film residues on wheat rhizosphere and soil properties

TLDR

Plastic mulch residues can accumulate in soils, raising environmental concerns, while biodegradable films offer a promising alternative, yet their effects on soil‑plant systems remain poorly understood. This study aimed to assess how macro‑ and micro‑sized residues of low‑density polyethylene and biodegradable plastic mulch films influence rhizosphere bacterial communities, volatile profiles, and soil chemical properties. Using a controlled pot experiment, the authors exposed wheat plants to macro‑ and micro‑plastic residues and measured bacterial community composition, volatile emissions, and soil chemical parameters. The results revealed that biodegradable plastic residues altered rhizosphere bacterial communities—enriching Bacillus and Variovorax—and induced unique volatile emissions such as dodecanal, while also causing significant changes in soil pH, electrical conductivity, and C:N ratio, underscoring their biotic and abiotic impacts on agroecosystems.

Abstract

Plastic residues could accumulate in soils as a consequence of using plastic mulching, which results in a serious environmental concern for agroecosystems. As an alternative, biodegradable plastic films stand as promising products to minimize plastic debris accumulation and reduce soil pollution. However, the effects of residues from traditional and biodegradable plastic films on the soil-plant system are not well studied. In this study, we used a controlled pot experiment to investigate the effects of macro- and micro- sized residues of low-density polyethylene and biodegradable plastic mulch films on the rhizosphere bacterial communities, rhizosphere volatile profiles and soil chemical properties. Interestingly, we identified significant effects of biodegradable plastic residues on the rhizosphere bacterial communities and on the blend of volatiles emitted in the rhizosphere. For example, in treatments with biodegradable plastics, bacteria genera like Bacillus and Variovorax were present in higher relative abundances and volatile compounds like dodecanal were exclusively produced in treatment with biodegradable microplastics. Furthermore, significant differences in soil pH, electrical conductivity and C:N ratio were observed across treatments. Our study provides evidence for both biotic and abiotic impacts of plastic residues on the soil-plant system, suggesting the urgent need for more research examining their environmental impacts on agroecosystems.