Mulches and Microplastic Pollution in the Agroecosystem

Abstract

In recent decades, organic (plant and animal residues) and inorganic (plastic polyethylene) mulches have become globally considered an environmen-tally friendly agricultural practice for their instant benefits, such as preserving soil moisture, reducing soil evaporation, improving water efficiency, soil temperature regulation, shorten growth of weeds, enhancing microbial activity in the soil, higher yields, early harvesting, and improved crop quality. Similarly, the use of plastic mulch as a amendment for the restoration of contaminated soils is becoming increasingly popular, and its application is expanding. In the agroecosystem, microplastics with a particle size of 5 < mm can enter the soil either directly through irrigation water, application of biosolids, and atmospheric deposition or indirectly via the in situ degra-dation of large pieces of plastic mulch films. The legacy of this is that many soils are now contaminated with large amounts of plastic residues, and it is crucial for evaluating the risk of soil-borne emerging microplastic pollution. Thus, the problem associated with the use of plastic mulch remains poorly understood in the agroe-cosystem. Therefore, in this chapter, we critically discuss the recent understanding of the use of inorganic mulches related to microplastic pollution in the soil envi-ronment. The sources of inorganic mulches in the agroecosystem, distribution, and migration of microplastic in soils, mechanisms of soil microplastic, constraints and dynamic behavior of microplastics during aging on land, explore the responses of soil fauna to plastic particles at microscales, and mitigation strategies to prevent microplastic pollution is proposed.