Evaluating the efficacy of nano-NPK liquid fertilizer on rice: Impact on physiology, grain quality and soil microbial communities

Nano-fertilizers offer a sustainable strategy to improve nutrient-use efficiency while reducing reliance on conventional fertilizers. This study investigates the efficacy of foliar-application of nano-NPK liquid fertilizer in rice. The effects of fertilizers were examined through changes in physiological responses, grain quality and soil microbial communities. A field experiment was conducted during the Rabi 2023-24 and Kharif 2024 seasons with nine treatments in which different concentrations (50, 75 and 100 %) of Recommended Dose of Fertilizers (RDF) were used along with one or two foliar sprays of 1 % nano-NPK at the tillering and panicle initiation stages. Key parameters assessed included chlorophyll content, NDVI, amylose, crude protein content and microbial populations. Results indicated that the application of 100 % RDF, combined with a foliar spray of 1 % nano-NPK at the tillering stage, significantly enhanced physiological traits and grain quality. This performance was statistically comparable to 100 % RDF alone and 75 % RDF with two nano-NPK sprays at tillering and panicle initiation stages. Notably, nano-NPK foliar spray without basal NPK led to substantial increases in soil microbial populations. These findings suggest that reduction (about 25 %) in conventional NPK inputs can be maintained through supplementation of nano-fertilizers. This was evident through rice productivity and improved soil health via enhanced nutrient-use efficiency. The findings suggest that nano-fertilizers can act as a sustainable alternative to conventional fertilizers and help in coping up seasonal variability in rice production.