Foliar Feeding of Gromor Nano DAP on Physiological, Biochemical and Nutritional Changes in Rice

Field experiments were conducted during two crop seasons ( Rabi 2023 and Kharif 2024) to determine physiological, biochemical and nutritional responses of rice to the foliar spray of nano DAP (nDAP) in comparison to conventional DAP. The data on SEM images showed that nDAP gets absorbed by leaves rapidly within 2 hours in comparison to cDAP (> 12 hrs). Combined application of 75% RDP with two rounds of nDAP at critical stages had significantly higher photosynthetic rates (3.4–7.7%), stomatal conductance (18–23%), transpiration rate (6–7%) and SPAD (12.9–16.6%) than cDAP spray. Nitrogen assimilatory enzymes NR (nDAP 21.6; cDAP 18.9 µg NO ₂ g ^− 1 h ^− 1 ), GS (nDAP 240.8; 160.2 µmol g ^− 1 FW h ^− 1 ), GOGAT (nDAP 207.5; cDAP 194.4 µmol NADH g ^− 1 FW h ^− 1 ) and ASP (nDAP 654.2; cDAP 531.7 µmol g ^− 1 h ^− 1 ) activities were higher in nDAP than cDAP sprayed plants. Nano DAP sprayed rice plants had higher N and P contents in critical growth stages. Data showed that nDAP gets absorbed in the plant system rapidly and orchestrate the physiological processes and nitrogen and phosphorous assimilatory pathways that collectively contributed for the improved N and P contents. This one of the early reports suggesting insights involved in nDAP sprayed plants leading to nutrient status.