Biodegradable CMC/Zn/Ca/Cu cross-linked novel superabsorbent hydrogel bead for plant pathogen prevention and agricultural applications

Abstract

Multi-nutrient-loaded biodegradable and biocompatible carboxymethyl cellulose-based zinc, calcium, and copper cross-linked hydrogel bead (CMC@CC) was prepared through an ionic cross-linking method. Further, nitrate was loaded in CMC@CC to obtain NCMC@CC. Under optimized conditions, CMC@CC showed an equilibrium swelling ratio of ∼915% in distilled water. The swelling kinetics of the hydrogel bead in water under optimized conditions followed both Fickian diffusion and second-order kinetic models. NCMC@CC exhibited a slow-release profile of nitrate in water and was better fitted by the Korsmeyer–Peppas model, and the release of nitrate was controlled by diffusion mechanism. The functional efficacy of the NCMC@CC nanocomposite beads was investigated by studying the growth pattern of tomato plants (Solanum lycopersicum L.) in soil. The application of NCMC@CC showed significant growth compared with control treatment. In vitro antibacterial study of the prepared hydrogel bead against Ralstonia solanacearum F1C1, a plant pathogen responsible for wilt disease in tomato, revealed that the prepared hydrogel bead possessed great bactericidal efficacy. These dual functional hydrogel bead could simultaneously reduce the application of pesticides and fertilizers for plant growth, thus promoting sustainability.