impact of nano-chelated npk and chemical fertilizers on the growth and productivity features of maize (zea mays l.) under water-deficit stress

Objective: drought stress is one of the most important factors limiting the development and production of maize worldwide. in this regard, using nano-fertilizers to control the release of nutrients can be a practical step towards achieving sustainable agriculture and environmental adaptation, and it is vital to induce drought stress tolerance in maize.methods: we aimed to evaluate the effect of nano-chelating-based nitrogen and npk fertilizers on both agronomic and physiological characteristics of maize under water-deficit stress conditions. a split-plot experiment was conducted based on a randomized complete block design to test the effect of the different fertilizers. the main plots included two levels of irrigation: optimum irrigation and water-deficit stress (irrigation after 140 mm evaporation from a class a pan). the subplots involved various combinations of nano-chelated fertilizers at five doses, alongside a control using conventional chemical fertilizers.results: our results indicated that water-deficit stress adversely impacted various growth and productivity characteristics in maize. however, substituting conventional chemical fertilizers with nano-chelated fertilizers, even at a minimal level (10%), notably enhanced most studied traits compared to the control under water-deficit stress conditions. specifically, treating plants with 222 kg/ha (treatment 3 of the nano-chelated fertilizers (nano-chelated n20p20k20 96 kg/ha + nano-chelated nitrogen 126 l/ha) of nano-chelated fertilizers instead of 840 kg/ha of chemical fertilizers (300 kg/ha of triple superphosphate, 150 kg/ha of potassium sulfate, and 390 kg/ha of urea) resulted in a 33% increase in grain yield, overall improvements in yield components, and elevated nitrogen use efficiency under drought stress. furthermore, nano-chelated fertilizers mitigated the impact of water-deficit stress through the chlorophyll a and b content while reducing leaf temperature.conclusion: our results indicated that nano-chelating-based macronutrient fertilizers could present a promising avenue within sustainable production systems, particularly under water-deficit stress conditions. therefore, considering production costs and environmental problems, the application of nano-chelated n20p20k20 96 kg/ha + nano-chelated nitrogen 126 l/ha for the sustainable production of grain yield in the fajr cultivar of maize will be sufficient, and higher levels of nano-fertilizers will be luxurious.