Abstract
With the growing challenge of microplastics (MPs) pollution, long-term real-time monitoring of MPs distribution remained difficult. Using nationwide field data and machine learning, we investigated MPs abundance and size distribution across China, key drivers, and future trends of MPs under multi-scenarios: sustainable development scenarios (SDSs), business-as-usual scenario (BAU), and high-forcing scenarios (HFSs). Results indicated that the average abundance of MPs in agricultural soils was 2,176 items/kg in 2020, with most particles smaller than 1 mm. The history of mulching film use (HistMF) was identified as the dominant factor influencing both MPs abundance and size, while climate variables such as radiation, temperature, and humidity further intensified fragmentation. Without intervention, MPs could exceed 10,000 items/kg by 2050 under the HFS. This research highlighted the need to strengthen mulching film production and plastic waste management in farmlands, particularly in regions with extreme climatic conditions, and provided scientific support for MPs control.