E. Kolentsova1, A. Mitkov2, N. Nguyen1, T. Tonev2, K. Ivanov1
1 Agricultural University, Faculty of Plant Protection and Agroecology, Department of Chemistry and Phytopharmacy, 4000 Plovdiv, Bulgaria
2 Agricultural University, Faculty of Agronomy, Department of Farming and Herbology, 4000 Plovdiv, Bulgaria
Kolentsova, E., Mitkov, A., Nguyen, N., Tonev, T. & Ivanov, K. (2023). Agronomic response of maize hybrids to foliar fertilization with nanosized zinc hydroxy nitrate. Bulg. J. Agric. Sci., 29 (2), 304–311
Recently, nanotechnology has offered the practice of a new generation of foliar fertilizers containing nanoparticles. One of the most promising zinc-containing foliar fertilizers is zinc hydroxy nitrate. Along with this, important aspects of its application in practice, such as the number and timing of sprays and the agronomic response of different maize hybrids, remain understudied.The objective of this study was to investigate the agronomic responses of maize hybrids to foliar fertilization by zinc in the form of zinc hydroxy nitrate suspension. Grain yield and its components were used as evaluation criteria. A total of ten hybrids from three maturity groups (FAO 400, 500 and 600/700) were tested. Considerable differences were found between the groups for the grain yield parameters. Furthermore, a significant effect of Zn application was observed for grain yield, which increases up to 12.2% for P0216 FAO 480. The best effect is obtained by double spraying at 4–5 fully emerged leaf and 8–9 fully developed leaf. The most sensitive to foliar zinc fertilization are the hybrids from the early maturity group FAO 400. No direct correlаtion was found between foliar zinc fertilization and protein, fat and starch content in the maize grains. The preparation of the zinc hydroxide nitrate with composition Zn5 (OH) 8(NO3)2·2H2O was performed by pouring a NaOH solution into Zn (NO3)2·6H2O under vigorous stirring. All samples were characterised in detail by thermal analysis, X-ray diffraction, scanning electron microscopy, and inductively coupled plasma (ICP) mass spectrometry to determine their physicochemical properties, morphology and content. The field experiment was conducted in four variants, three repetitions for each hybrid. It was concluded that the synthesised zinc hydroxy nitrate has pоtential as a successful long-term foliar fertilizer.