Biodegradable polyesters in soil—Real environmental hazard or just a storm in a teacup?

Biodegradable polyesters (BPEs) are increasingly being promoted as sustainable alternatives to conventional plastics, particularly in applications where biodegradability offers an advantage because material retrieval is impractical or impossible. Agriculture is a typical example of such applications. However, the growing interest in BPEs has also raised legitimate concerns regarding potential environmental side effects, especially the formation and fate of biodegradable microparticles (“microbioplastics”) in soils. This review critically examines the current understanding of the degradation mechanisms, ecological interactions, and environmental implications of BPEs under soil conditions. Evidence suggests that, at environmentally and agriculturally realistic loading rates, most effects on soil properties are transient and comparable to those induced by natural biodegradable organic inputs such as lignocellulose. Fragmentation of and biofilm formation on BPEs, often interpreted as adverse effects, are in fact inherent stages of microbial degradation and carbon cycling. Overall, assessing the impact of BPEs on soil ecosystems remains a highly relevant and rapidly evolving research area, requiring adherence to sound scientific principles, realistic exposure scenarios, and standardized methodologies. Integrating microplastic characterization and temporal analyses into future certification and testing frameworks will strengthen the scientific foundation for evaluating the environmental safety of these materials and support their responsible implementation in sustainable agriculture and soil management.