Distribution characteristics, influencing factors, and future prospects of microplastics derived from agricultural mulching film in farmland soil: a review

Microplastics (MPs, particle size<5 mm), as an emerging pollutant, can exist in the environment for a long time and have been widely found in global agricultural ecosystems. MPs can alter soil physical and chemical properties, interfere with microbial communities, adsorb and transmit pollutants, directly or indirectly affecting crop growth and agricultural product quality and safety. Generally, MPs in ecosystem could be originated from a diverse array of sources. Except for atmospheric deposition, tire wear, farmland irrigation, and sludge application, plastic-coated fertilizers and mulching films used in agriculture have become sources of concern. Recently, a large number of studies have reported on the distribution and pollution mechanisms of MPs in marine environments, but there are relatively few studies on the distribution characteristics and influencing factors of MPs generated by plastic film mulching in different regions. This paper will explore the distribution characteristics of MPs in farmland soil in different countries and regions and their impacts on crop physiology and ecology. It will also analyze the roles of factors such as farmland types, plastic film types, mulching years, mechanical recovery methods, cultivation systems, and farmland irrigation in the distribution characteristics of MPs originated from plastic film. Finally, it will propose to manage policy recommendations, research frontiers and focus fields.