Nutrient controlled release behaviors and plant growth of NPK encapsulated hydroxyapatite/alginate biocomposite toward agricultural and environmental sustainability

Abstract

Controlled release fertilizers (CRFs) promote sustainable agriculture by gradually releasing nutrients into the soil while also mitigating environmental pollution. Nitrogen-phosphorus-potassium embedded hydroxyapatite/alginate (NPK-HA/Alg) biocomposite beads were developed using a simple, cost-effective, and environmentally friendly dropping and external gelation method. Addition of eggshell biowaste-derived HA to the alginate matrix improved the structural, thermal, and structural stability of the alginate beads, and enabled the inclusion of significantly high plant nutrients. The biocomposite beads exhibited a prolonged and controlled nutrient release in deionized water over 35 days. Biocomposite bead addition was assessed for the growth of flowering Chinese cabbage in a controlled greenhouse environment. Results confirmed vegetative growth with high values of plant height, number of leaves, and fresh and dry weights. The non-toxic and cost-effective NPK-HA/Alg biocomposite beads demonstrated controlled nutrient release as promising CRF materials to promote sustainable agricultural production.

Keywords

• controlled release fertilizers
• biocomposites
• alginate
• hydroxyapatite
• sustainable agriculture