The size-variation of microplastics alter plant nitrogen uptake by regulating soil gross nitrogen transformation rates

The accumulation of microplastics (MPs) has been shown to affect ecosystem nitrogen (N) cycling. However, direct quantitative studies investigating how variations in MPs type and size affect soil N processes and plant N uptake are still lacking. Thus, a 15N tracing was carried out to investigate the effects of variations in size of conventional polyethylene (PE-MPs) and biodegradable polylactic acid MPs (PLA-MPs) on the interactions between soil gross N transformation and plant N uptake rates. Our findings highlight that the extent to which MPs influence N processes depends on their type and size. The small-size degradable MPs can pose a major threat to plants, so the managements of degradable plastics requires special attentions.