Do biodegradable plastic residues pose lower ecological risks to crops than conventional plastic residues? A...

Agriculture is a major application area for biodegradable plastics. However, whether biodegradable plastic residues (BPRs) pose lower ecological risks to crops than conventional plastic residues (CPRs) remains uncertain. We conducted a meta-analysis of 1530 paired comparisons extracted from 55 studies using a rigorous pairwise comparison methodology to directly compare BPRs with CPRs. Compared to CPRs, BPRs significantly reduced shoot biomass by 11.5 %, root length by 9.52 %, and Cu content by 20.58 %, while increasing root oxidative damage by 19.72 %. No statistically significant differences were observed in germination rate, shoot morphology, total biomass, photosynthetic pigments, net photosynthetic rate, or antioxidant enzyme activities. The detrimental effects of BPRs relative to CPRs intensified with increasing plastic concentration. Although plastic size, shape, BPR type, crop type, initial pH, initial soil organic matter (SOM) content, and exposure time showed limited influence overall, several of these factors modulated the effects under specific conditions. Notably, BPRs significantly reduced root biomass and impaired root morphology compared to CPRs under acidic and low-SOM conditions. Given the limitations in existing literature, particularly the short exposure durations and the predominant use of virgin plastics, it remains premature to draw a definitive conclusion regarding whether BPRs pose greater or lesser risks to crops than CPRs.