Chitosan xerogel embedded with green synthesized cerium oxide nanoparticle: An effective controlled release fertilizer for improved cabbage growth.

With the growing awareness on the adverse effects of conventional fertilizers; the use of sustainable and controlled release fertilizers has garnered much significance. In the present study, we report the synthesis of chitosan-benzaldehyde Schiff base xerogel incorporated with green synthesized cerium oxide nanoparticle using Psidium guajava leaves extract as a sustainable fertilizer. Spherical CeO NPs having an average particle size of 15.3 nm and zeta potential of - 39.9 mV was obtained. The urea-loaded nanocomposite xerogel (CsB@U/CeO) was examined for cabbage growth. The water retention capacity extended for >2 weeks. A controlled release profile for urea was accomplished from CsB@U/CeO for a period extending for 30 days. The kinetics assay suggested that presence of CeO NPs asserted a greater role in urea-controlled release from the CsB@U/CeO nanocomposite hydrogel owing to polymer relaxation. The growth parameters of cabbages such as head height, diameter, fresh head weight, head circumference was enhanced in plants fertilized by CsB@U/CeO as compared to urea. Furthermore, the phenolic content, free radical scavenging activity, protein content, sugar and flavonoid content were also found higher in CsB@U/CeO fertilized plants. This study puts forth CsB@U/CeO xerogel can be potentially harnessed as an alternative to urea in sustainable agriculture.