Microplastics in the agroecosystem: effects of plastic mulch film residues on the soil-plant system

Due to the widely use of plastic mulch in agriculture, plastic residues in the soil are threatening soil quality. In this thesis, we assessed the effects of macro and micro sized plastic residues from polyethylene and biodegradable plastic mulch films on the soil-plant system, by investigating their effects on plant growth, rhizosphere microflora, soil physicochemical properties and soil functions.

Overall, this thesis provided experimental evidence that plastic mulch film residues affected physical, chemical and biological processes in the soil-plant system. Despite the lack of knowledge, it is clear with the incipient evidence that both macroplastics and microplastics derived from LDPE and biodegradable plastic mulch films could be detrimental to agricultural productivity, soil biodiversity and soil biogeochemical cycles. Moreover, the insights developed during this PhD research are a valuable contribution to a framework for the systematic analysis of the effects of microplastics on the soil-plant system and a holistic approach to study interrelated physical, chemical and biological processes in the agroecosystem.