Abstract
Microplastics (MPs) in agricultural plastic film mulching system changes microbial functions and nutrient dynamics in soils. However, how biodegradable MPs impact the soil gross nitrogen (N) transformations and crop N uptake remain significantly unknown. In this study, we conducted a paired labeling 15N tracer experiment and microbial N-cycling gene analysis to investigate the dynamics and mechanisms of soil gross N transformation processes in soils amended with conventional (polyethylene, PE) and biodegradable (polybutylene adipate co-terephthalate, PBAT) MPs at concentrations of 0 %, 0.5 %, and 2 % (w/w). The biodegradable MPs-amended soils showed higher gross N mineralization rates (0.5–16 times) and plant N uptake rates (16–32 %) than soils without MPs (CK) and with conventional MPs. The MPs (both PE and PBAT) with high concentration (2 %) increased gross N mineralization rates compared to low concentration (0.5 %). Compare to CK, MPs decreased the soil gross nitrification rates, except for PBAT with 2 % concentration; while PE with 0.5 % concentration and PBAT with 2 % concentration increased but PBAT with 0.5 % concentration decreased the gross N immobilization rates significantly. The results indicated that there were both a concentration effect and a material effect of MPs on soil gross N transformations. Biodegradable MPs increased N-cycling gene abundance by 60–103 %; while there was no difference in the abundance of total N-cycling genes between soils without MPs and with conventional MPs. In summary, biodegradable MPs increased N cycling gene abundance by providing enriched nutrient substrates and enhancing microbial biomass, thereby promoting gross N transformation processes and maize N uptake in short-term. These findings provide insights into the potential consequences associated with the exposure of biodegradable MPs, particularly their impact on soil N cycling processes.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
