Novel Developments in Nano Fertilizer for Sustainable Crop Production to Promote Global Food Security

The increased demand for food worldwide has led to the widespread use of synthetic chemical fertilizers. Since the Green Revolution, the use of such chemical fertilizers has been in high demand as a nutrient input in agriculture. The increased application of fertilizer to upsurge crop yields is not suitable for the long term and leads to nutrient loss, as well as severe environmental and ecological consequences. In contrast to conventional fertilizers, nano fertilizers, which are designed at the 1–100 nm size, provide focused nutrient delivery, decreased leaching, and improved plant absorption. They accomplish this by greatly increasing crop yields, enhancing fertilizer usage efficiency, and facilitating sustainable farming in the face of obstacles, including resource scarcity, climate change, and a projected population size of 10 billion by 2050. In comparison to typical NPK fertilizers at equal nutrient rates, nano fertilizers enhanced crop yields by an average of 20–23% across cereals, legumes, and horticulture crops according to studies conducted between 2015 and 2024. In particular, using nano urea with rice increased grain yields by 28.6% with 44% less nitrogen input, and applying nano zinc to wheat increased yields by 31.2% and improved the grain’s Zn content by 41%. Through targeted foliar or soil application, nano fertilizers frequently increase nutrient use efficiency (NUE) by more than 50% as opposed to 30–50% for conventional fertilizers. Nano fertilizer is prepared based on the encapsulation of plant essential minerals and nutrients with a suitable polymer matrix as a carrier and then delivered as nano-sized particles or emulsions to the plants. Natural plant openings like stomata and lenticels in plant parts facilitate the uptake and diffusion, leading to higher NUE. This review provides an overview of current knowledge on the development of advanced nano-based and smart agriculture using nano fertilizer to improve nutritional management. Furthermore, nanoscale fertilizers and their formulation, nano-based approaches to increase crop production, the different types of fertilizers that are currently available, and the mechanism of action of the nano fertilizers are discussed. Thus, it is expected that a properly designed nano fertilizer could synchronize the release of nutrients in crop plants as and when needed.