Foliar nanofertilizers: Effects on crop uptake, yield and soil health in puddled transplanted rice

The primary aim of the study was to investigate the impact of foliar application of nano-formulated nutrients-specifically nano nitrogen, nano phosphorus and nano potash-on the growth, development and yield performance of transplanted rice cultivated under puddled soil conditions. A field experiment took place from December 2023 to April 2024 during the late Rabi season at the Department of Agronomy, V.O.Chidambaranar Agricultural College and Research Institute, Killikulam, Tamil Nadu, India. The experiment used a randomized block design with fourteen treatments, consisting of various combinations of nano NPK with different times of foliar application and three replications. The soil of the experimental plot was sandy clay loam with a pH of 7.73, which is slightly saline in nature. The soil contains organic carbon of 6.41 g/kg, with available nitrogen at 287.42 kg/ha, available phosphorus at 25.15 kg/ha and available potassium at 152.37 kg/ha. The results showed that the 100 % recommended dose of fertilizer (RDF) in rice treatment achieved the highest nutrient uptake (N, P, K) and, in turn, the grain yield, while foliar application of nano N, P and K fertilizers, particularly when applied four times, closely matched with the performance of RDF. Nanofertilizers enhanced nutrient absorption due to their smaller particle size and better leaf penetration. However, both RDF and nano foliar fertilization had minimal impact on soil chemical properties (pH, EC and organic carbon) and microbial activity, indicating that nutrient delivery primarily occurred through the foliage rather than altering the soil environment. In terms of economics, foliar application of nano N, P and K at three times was more cost-effective and profitable than four times in puddled transplanted rice.