Plasticized Poly(vinyl alcohol)/Starch as a Nutrient Delivery System for Macro and Micronutrients

Concerns about the environmental and economic impacts of agrochemical usage highlighted the importance of enhanced efficiency fertilizer materials to achieve the 2030 agenda for sustainable development. Therefore, we melt-processed a macro/micronutrient mono and multicomponent material based on poly(vinyl alcohol), KNO₃, and starch/micronutrient (Mn, Fe, and Cu) microspheres. The Multimaterial presented a release reduction of 50 and 60% to K⁺ and NO₃^–, respectively, compared to the Macromaterial, due to the external PVA layer, relaxation process, nutrient diffusion decrease, and ion competition (the presence of the micronutrient). In the soil release, the initial burst release occurred 12 days earlier for Multi and commercial material Basacote compared with the Macromaterial due to the presence of micronutrients. However, after 80 days of nutrient release in the soil, the materials still presented nutrients in the composition as determined by XRD, FTIR, and SEM-EDS analysis. Also, SEM images of the surface showed signs of deterioration, confirming their biodegradation potential over time and a similar release profile to the commercial material.