Nano Nutrient Foliar Application: Impacts on Yield, Quality, and Nutrient Efficiency in Dryland Finger Millet

ABSTRACT Background Nitrogen and zinc are the most critical macro‐ and micronutrients that significantly determine the crop productivity. Foliar application of these nutrients is a proven technology to abate acute deficiency at any crop‐growing stage. Recent developments in the field of nanotechnology such as spraying of nano‐urea and nano zinc in combination with conventional fertilizers enhance crop growth and nutrient use efficiency (NUE) of crop. Aim This investigation assessed the impact of nano nutrient foliar sprays on the growth, yield, qualitative and quantitative traits, and nutrient utilization efficiency of finger millet. Methods Experiment was conducted at AICRP for Dryland Agriculture, UAS, GKVK, Bengaluru during Kharif 2021 with finger millet as test crop. It comprises 12 treatments with different levels of nitrogen in combination with foliar application of nano nutrients at 35 and 55 DAS. Results Foliar application of nano‐N and nano‐Zn along with 100% RDN + recommended PK in finger millet significantly enhanced the growth, yield, and nutrient utilization efficiency of finger millet. Application of 100% RDF + foliar spray of nano‐N and nano‐Zn recorded the highest grain yield (3486 kg ha −1 ) and straw yield (4810 kg ha −1 ), significantly outperforming treatments with conventional fertilizers alone. This treatment also improved the qualitative attributes such as the number of ear heads (6.53), length of ear heads (6.95 cm), and dry weight per plant (146.80 g). Similar was the trend with antioxidant enzymes, namely, catalase and peroxidase activity, proximate composition of finger millet grain with higher crude protein (8.88%), crude fiber (2.90%), ash (2.40%), and fat (1.46%). Moreover, this treatment also recorded the highest economic returns, with gross returns of Rs. 108,192 ha −1 and net returns of Rs. 79,579 ha −1 , making it the most effective and beneficial strategy for finger millet cultivation under dryland conditions. Conclusion The productivity and NUE of finger millet were higher with foliar application of nano nutrients along with 75% RDN + recommended PK and were found to be cost‐effective compared to conventional fertilizers alone.