Digestate application accelerates the aging of agricultural mulch microplastics and reshapes soil biochemical and microbial processes

Soil samples were collected from an agricultural field in Guangdong Province. During sampling, surface litter and visible plant debris were removed. Soil from the 0 to 20 cm topsoil layer was collected and placed in an insulated box. Upon return to the laboratory, samples were air-dried at room temperature. They were then sieved through a 2 mm stainless steel mesh to remove stones, roots, and other impurities, thoroughly mixed, and stored for subsequent use.