Biodegradation and viability of chitosan-based microencapsulated fertilizers

[Display omitted] •Encapsulation of KNO3 nutrient by chitosan and clay using spray drying technique.•Inorganic materials, clay and fertilizer, influence biodegradation.•EEF formulations based on chitosan and clay can be considered biodegradable.•Relationship of material biodegradation and soil-water release properties.•Effect of chitosan degradation during storage time on biodegradation. Enhanced efficiency fertilizers (EEF) are an important subject for sustainable materials. It is fundamental for the released nutrient and biodegradation in the soil to have synergy to ensure material harmlessness. Chitosan, montmorillonite, and KNO3 were considered to develop the EEF because of the high biodegradation potential of the final product. We correlated the material biodegradability and release in water and soil to their formulation. We assume the materials are biodegradable since the biodegradation efficiency achieved over 30 %. As the nutrient diffusion and matrix degradation happen concomitantly, we also observed that the clay delays degradation and the KNO3 improved it. Likewise, the storage period can change the biodegradability properties once the material started to degrade. Hereupon, the amount of nutrient delivered will match the amount consumed by the plant, the matrix will degrade and no residue will be left in the soil.