EFFECTS OF NANO-FOLIAR NUTRITION ON GROWTH AND YIELD OF BARLEY CULTIVARS IN SOUTHERN IRAQ

The study aims to determine the optimal concentration of nano-microelements in a two-year (2021–2023) field experiment that maximizes crop yield and quality, as well as to understand the interactions between individual barley varieties (‘Buraq’, ‘Aba 99’, and ‘Aba 265’) and the applied concentrations of nano-microelements. This study also aims to develop variety-specific nano-fertilization protocols for sustainable barley production. A randomized complete block design with three replications was implemented as a split-plot design. Treatments consisted of foliar application of nano-micronutrient fertilizers containing B, Cu, Fe, Mn, Zn, and Mo at 0 (control), 1 g L⁻¹, and 2 g L⁻¹. Results showed that the number of spikes m⁻², the number of grains per spike, and the grain yield of each cultivar increased significantly with treatments. The 2 g L⁻¹ treatment produced the largest increase in yield (from 3.7 to 4.2 t ha⁻¹ for ‘Buraq’; from 4.2 to 4.9 t ha⁻¹ for ‘Aba 99’; and from 4.7 to 5.6 t ha⁻¹ for ‘Aba 265’). Genotypic differences were also observed; ‘Aba 265’ consistently produced the greatest number of spikes per unit area and the highest final yield. These findings demonstrate how the use of both application rates of the foliar nano-micronutrients significantly improves nutrient use efficiency and overall productivity of barley grown under low soil micronutrient supply.