Impact of Novel Bio-Based and Polyethylene Mulch Films on Folsomia candida and the Micro-Arthropod Community by the QBS-ar Approach

Polyethylene mulching films are a major source of plastic pollution in agricultural soils especially due to improper end-use disposal. This global plastic waste problem has promoted the development of biodegradable mulching films able to fully decompose in soil after their use. This study aimed at evaluating the effect of polyethylene, Mater-Bi® and innovative carboxymethylcellulose-, chitosan- and alginate-based biodegradable mulch films, either enriched or not with monoammonium phosphate (MAP) on soil micro-arthropods. The enrichment of the mulch film with MAP has the purposes of (i) promoting microbial breakdown at the end of the cropping cycle balancing the substrate and (ii) supplying phosphorus and ammonium as a fertilizer to the soil. Acute toxicity responses were assayed in vitro using the non-target model micro-arthropod Folsomia candida. Furthermore, outdoor mesocosms tested mulch films on micro-arthropod community using the QBS-ar approach. The assessment also included a consortium of cellulose–chitosan-degrading bacteria. Neither all the mulch films tested nor their components exhibited acute toxicity at double concentrations used in field applications. Results from mesocosms mulched with innovative bio-based mulch films are consistent with an improvement in biological soil quality. Thus, the innovative bio-based mulch films assessed in this study have the potential to boost soil communities while reducing plastic pollution in agricultural fields.