Mitigating Abiotic Stress and Enhancing Crop Yield Through Micronutrient-Based Nano Fertilizer

Micronutrient deficiencies are a critical barrier to sustainable agriculture, significantly impacting crop yield and quality worldwide. Iron (Fe), copper (Cu), and zinc (Zn) deficiencies are particularly prevalent in plants grown in calcareous soils due to their high alkalinity, low organic matter content, and unfavourable texture, which limit nutrient bioavailability. Conventional fertilizers often exhibit poor nutrient efficiency due to leaching, fixation, and volatilization, necessitating advanced solutions such as micronutrient-based nano fertilizers (MNFs). These nanomaterials leverage unique physicochemical properties, including high surface-area-to-volume ratio, enhanced solubility, controlled nutrient release, and increased bioavailability, to optimize plant nutrient uptake and mitigate soil nutrient depletion. This review explores the role of ZnO, CuO, and Fe₂O₃ nanoparticles in improving nutrient use efficiency (NUE), enhancing photosynthetic activity, and promoting stress tolerance under various abiotic conditions, including salinity, drought, and heavy metal toxicity. Furthermore, it examines the environmental fate of nano-fertilizers, potential ecotoxicological concerns, and regulatory challenges associated with their large-scale application. While MNFs hold promise for revolutionizing precision agriculture and soil fertility management, further research is required to develop standardized formulations, assess long-term soil-microbe interactions, and integrate nano-enabled fertilizers into sustainable agricultural systems.