Advancing sustainable agriculture: Evaluation of Poly (lactic acid) (PLA) based mulch films and identification of biodegrading microorganisms among soil microbiota

Non-biodegradable polyolefin based plastic mulch residues in agricultural fields after the end of a crop cycle have raised several concerns as an environmental pollutant in recent years. This study explores the potential of Poly (lactic acid) (PLA) and Poly (butylene adipate-co-terephthalate) (PBAT) based compostable films reactively blended with compatibilizers and chain extenders as a promising solution to environmental challenges associated with traditional plastic mulch films. Epoxidized soybean oil (ESO) and Epoxy-functionalized styrene acrylic copolymer (ESA) have been used as reactive compatibilizers and chain extenders respectively. In-depth analysis of the mechanical, thermal, and barrier properties of the developed films, revealed that the PLA/PBAT blend films at 75:25 weight ratio in the presence of 5 phr ESO and 0.5 phr ESA exhibit improved performance characteristics for application as mulch films. Furthermore, the films were subjected to 360-h UV exposure to gauge their stability under prolonged exposure, specifically investigating changes in the carbonyl index. Additionally, a rigorous real-time field trial of the mulch films spanning eight months with various crops was carried out to understand their performance in practical agricultural settings. The study also involved the identification of microorganisms responsible for the degradation of the developed mulch films employing 16S rRNA sequencing.