Soil Microbial Biomass and Microarthropod Community Responses to Conventional and Biodegradable Plastics

Plastic mulch is a commonly employed technique in agriculture to enhance crop production. Given the persistence of plastic residues in soil, bioplastics offer a potential alternative. Unfortunately, little is known about the medium-term consequences of both plastic and bioplastic mulches on soil properties. This study aimed to assess the medium-term consequences of plastic and bioplastic mulches and their replacement on soil properties. To this aim, the impact of conventional plastic (polyethylene, CP) and biodegradable plastic (BP) mulches on soil’s abiotic (pH, water content, total and organic carbon and total nitrogen contents) and biotic (microbial biomass, microbial respiration, enzymatic activities and microarthropod communities) properties after 2 years of exposure (T1) and after 3 (T2) and 6 (T3) months of mulch replacement was investigated. Moreover, uncovered soils were assessed as a control. The results highlighted that the samples were more significantly impacted by exposure time to mulches than by the different kinds of mulches. The replacement of both mulches (T2 and T3) decreased the content of C and increased the microbial biomass and activities; moreover, the mulch replacement changed the microarthropod community composition with a decrease of Collembola and an increase of Oribatida and Gamasida, especially in soils covered by biodegradable plastic mulches. Further investigations are needed to better understand the long-term impact of mulches on soil biota in order to prove the potential ecological implications of transitioning to sustainable alternatives.