Effects of Nitrogen Aerosols on Biochemical Traits of Some Kharif Rice (Oryza sativa L.) Genotypes

Nitrogen (N) is a vital plant nutrient for crop growth and development. In tropics and subtropics, nitrogen is lost by leaching, runoff and volatilization. Foliar nutrition in crops has increased in importance alternative to soil application. In nature, the input of nitrogen is possible through dry and wet deposition of nitrogen or as aerosols on foliage. The responses of rice crops to aerosols of nitrogen linked to its productivity deserve strong attention in the present climate change scenarios globally. Therefore, a field experiment (2020) was conducted in ICR Farm, Assam Agriculture University to investigate into effects of N-aerosols on biochemical traits in 10 (ten) kharif rice genotypes. The aerosols viz., KNO3: NH4NO3 and Ca(NO3)2 @60 kg ha-1 (≈600ppm), 1000 cm3 each were sprayed at maximum tillering and heading stages of the rice crop. In the experiment, the nitrogen aerosols increased biochemical traits viz., contents of chlorophyll ‘a’ (40.91-91.66%) & (10.52-47.22%), chlorophyll ‘b’ (4.91-19.67%) & (6.89-10.34%), total chlorophyll (21.51-53.96%) & (23.42-39.03%), NR activity (64.21-95.92%) & (50.66-72.39%) at maximum and heading stages respectively, nitrogen in grains (13.04-22.61%), and protein in grains (13.49-20.72%). Moreover, there were increments in lipid peroxidation (4.71-107.14%) and Cell membrane stability (CMS) (5.72-29.85.92%), intercellular [K+] (20.23-70%), exchangeable [K+] (68.46-77.02%), intercellular [Ca2+] (6.77-17.80%) and exchangeable [Ca2+] (3.29-33.80%), which varied significantly depending on the types of the N-aerosols. In the experiment, the variety Gitesh showed the highest response to the N-aerosols irrespective of the crop growth stages. Further, among the N-aerosols, KNO3 was found to be the best followed by Ca(NO3)2 & NH4NO3, control distilled water in terms of the traits.