Green synthesis of ZnO nanoparticles: Characterization and emerging applications in sustainable agriculture

Zinc oxide nanoparticles (ZnO-NPs) synthesized through biogenic routes have emerged as a transformative solution for sustainable agriculture, addressing the limitations of conventional zinc fertilizers. Traditional fertilizers suffer from inefficiencies due to leaching, photodegradation, and microbial degradation, whereas biogenic ZnO-NPs leverage their nanoscale properties, such as high surface area, controlled-release mechanisms, and eco-friendly synthesis to enhance nutrient uptake and crop productivity. This review systematically evaluates plant-, microbial, and waste-mediated synthesis methods for ZnO-NPs, emphasizing their role in improving soil health, stress resilience, and yield in crops such as rice, wheat, and maize. Characterization techniques, including UV-Vis spectroscopy, FT-IR, XRD, and electron microscopy, confirm the structural and functional efficacy of these nanoparticles. Notably, fungal-mediated synthesis demonstrates superior scalability and stability, whereas plant-based methods offer rapid and low-cost alternatives. Applications of ZnO-NPs extend beyond nutrient delivery, showcasing antimicrobial activity, UV protection, and soil remediation capabilities. However, challenges such as toxicity thresholds, large-scale production, and farmer adoption necessitate further research. By bridging nanotechnology with agronomic practices, biogenic ZnO-NPs present a viable pathway to achieve food security, environmental sustainability, and reduced agrochemical dependency. • The green synthesis of ZnO nanoparticles has been discussed. • Applications of ZnO nanoparticles in the agriculture sector have been described. • Comparison of synthetic fertilizers and biogenic nanoparticles has been done. • The impacts of ZnO nanoparticles on the environment have been explored.