Advancements and challenges in controlled-release fertilisers: An approach to integrate biopolymer-based strategies

It is essential to ensure a consistent supply of affordable, nutritious food to meet the demands of our rapidly growing population. In this context, controlled-release fertilisers (CRFs) have been developed to address the ongoing issues in nutrient use efficiency and global food insecurity. CRFs facilitate a gradual and targeted nutrient delivery system to promote optimal plant growth. Despite their significance, worldwide adoption is hindered by more substantial production costs, insufficient synchronisation with plant nutrient uptake, and environmental implications of synthetic polymer-based fertilisers. Various delivery systems, including coatings, matrices and hydrogels, have been developed for sustainable release. Nonetheless, a key challenge is their potential failure to degrade in soil, which can lead to secondary microplastic contamination and adverse effects on the soil environment. The subsequent sections explore technology, stability, the economy, and environment challenges. This review is a pioneering effort to comprehensively explore the challenges and limitations of controlled-release fertilisers. In addition, this review investigates emerging strategies to overcome the barriers, mainly focused on the potential of biopolymers as sustainable materials. Biopolymers offer several advantages, including biodegradability, tuneable release profile, and compatibility with current farming practices. This review aims to better understand emerging applications of biopolymers in CRFs, and trends are identified and analysed to provide insight for future work in precision farming practices. • CRFs are promising tool for sustainable agriculture, addressing challenges is crucial. • Fossil fuel-based CRFs cause microplastics accrual, pose persistent issue in farmland. • Novel biopolymer-based CRFs reduce carbon footprint and acts as soil conditioner. • Research must prioritise optimising biopolymer blends, cutting costs, and scalability.