Atrazine integrated biodegradable poly (vinyl alcohol)/xanthan gum active films for mulching applications: An alternative to microplastic generation plastic mulch

Abstract

Plastic has become indispensable in various industries, including agriculture, due to its affordability and versatility. Overutilizing plastic in agriculture produces microplastics, which pose significant environmental damage and cause several health implications. Hence, biodegradable mulch films were produced as an alternative to plastic by integrating atrazine (PXA) into the Poly (Vinyl Alcohol)/Xanthan gum polymer blend by solvent casting method. The PXA mulch films exhibited a compact structure and a slight reduction in crystallinity due to the crosslinking caused by the atrazine herbicide. The PXA mulch films excelled over the current biodegradable mulches, demonstrating a tensile strength of 42.73 ± 0.51 MPa and an elongation at a break of 60.58 ± 1.21 %. The addition of atrazine improved the ability of the PXA mulch films to block ultraviolet (UV) radiation, suppress the water vapour transmission rate (WVTR), and enhance the hydrophobic properties. The PXA mulch films, buried in soil for 15d, exhibited a degradation rate of 7.50 ± 0.64 %, confirming their biodegradability. Herbicidal test was conducted with PXA mulch using Johnson grass as a weed. PXA mulch effectively retarded weed with enhancement of atrazine concentration. Kinetics investigations have verified that the release of the herbicide is governed by Fickian diffusion and exhibits a dependence on its concentration. For the impending harvest, soil fertility is also a crucial factor. PXA mulch films break down into organic matter to stimulate microbial development. Urease activity due to atrazine creates mulch soil rich in nitrogen content, and elevation in catalase activity ensures significant microbial development. These results of biodegradable PXA mulch films address the loss of soil fertility caused by applying PE mulching, which is the underlying cause of microplastic formation. These research findings suggest that PXA biodegradable mulch film could be an alternative to hazardous PE mulch in agriculture.