Antagonistic Effect\nof Microplastic Polyvinyl Chloride\nand Nitrification Inhibitor on Soil Nitrous Oxide Emission: An Overlooked\nRisk of Microplastic to the Agrochemical Effectiveness

Microplastics\nare widely persistent in agricultural ecosystems\nand may affect soil nitrous oxide (N<sub>2</sub>O) emissions. Nitrification\ninhibitor 3,4-dimethylpyrazole phosphate (DMPP) is applied to decelerate\nnitrification and reduce soil N<sub>2</sub>O emission. Nevertheless,\nthe interactive effects of nitrification inhibitors and microplastics\non soil N<sub>2</sub>O emissions have not been investigated. Sole\nDMPP, polyvinyl chloride (PVC), and polystyrene (PS) substantially\nreduced agricultural soil N<sub>2</sub>O emission rates by 25.93%,\n69.04%, and 73.89%, respectively. Nevertheless, PVC and DMPP had antagonistic\neffects on the N<sub>2</sub>O emission rates. The observed reductions\nin N<sub>2</sub>O emissions could be attributed to variations in soil\noxygen availability, electron transport system activities, and <i>Firmicutes</i>, nap, and GDH genes. Moreover, the DMPP, PVC,\nand PS alone or copresences significantly enhanced the soil ecosystem\nmultifunctionality (EMF). The findings shed light on the role of microplastics\nin soil N<sub>2</sub>O emission, EMF, and the microbial community,\nexpanding the understanding of microplastics’ effects on agrochemical\neffectiveness.