Abstract
The development of slow-release fertilizers has gained significant attention in the agricultural industry due to their ability to provide a gradual and sustained supply of nutrients to crops, enhancing nutrient efficiency and minimizing environmental impact. This study focused on the formulation and characterization of an innovative fertilizer coating on a hybrid matrix of sodium alginate (SA), lignin (LG), and calcium-modified montmorillonite clay (Ca2+-MMT). The coatings were prepared with varying loadings of Ca2+-MMT (0 %, 2 %, 5 %, and 10 % wt), and analyzed for their chemical structure, morphology, crystallinity, thermal stability, hydrophobicity, and mechanical properties using FTIR, SEM, XRD, TGA, contact angle and a tensile testing machine. Contact angle measurements revealed the hydrophobic nature of the SA-LG-Ca2+-MMT films. Notably, the mechanical properties were significantly influenced by the inclusion of 5 % Ca2+-MMT, showing a remarkable increase in tensile modulus by 19.15 %, tensile strength by 25.51 %, and a decrease in elongation at break by 52.04 % compared to the Ca2+-MMT-free formulation. Furthermore, the SA-LG20%–10 %-Ca2+-MMT coating demonstrated a significant increase in the slow release of phosphorus (P) in water (24 ± 5 % after 3 days) compared to 100 % P release with the uncoated triple superphosphate (TSP). These results highlighted the potential of this hybrid coating for enhanced nutrient management and sustained fertilizer efficiency in agricultural applications.