Environmental impacts and challenges of biodegradable plastic mulches in agricultural soils

In modern agriculture, mulching has emerged as a fundamental agronomic practice for regulating soil temperature and conserving moisture. This practice has evolved from organic materials such as straw and crop residues, to the widespread use of durable polyethylene (PE) films. However, the use of PE mulches and their persistence cause environmental degradation leading to white pollution. The residues break into microplastics, and pose long-term risks to soil health, biodiversity, and ecosystem. Research indicates that Biodegradable plastic mulches (BDMs) provide agronomic benefits comparable to PE mulches while offering added advantage of in situ biodegradation. BDMs represent a sustainable alternative to conventional PE mulches. Moreover, it eliminates the need for post-harvest retrieval, significantly reducing labour and disposal costs. This review paper analyses the progression from plastic to bioplastic for mulching by evaluating their sources, biodegradability, agronomic benefits, supply chains, environmental impacts, and human health effects. It also explores the constraints in upscaling bioplastics that include high production costs, nascent technologies, feedstock sustainability concerns, and limited industrial capacity. Future research should prioritize ecosystem-specific BDM formulations, enhanced cost-effectiveness, and long-term evaluations supported by robust life-cycle assessments of ecological and human health impacts.