THE PRESENT study was conducted at the Experimental Farm of the Faculty of Agric., MansouraUniversity. Six treatments were arranged in Randomized Complete Block Design with three replications as follows: 50% and 100% from the recommended doses (RD) of NPK, 300 Fe mg L^-1 + 50% from RD of NPK, 50 Cu mg L^-1 +50% from RD of NPK, 100 Zn mg L^-1 + 50% from RD of NPK and Fe + Cu + Zn + 50 % from RD of NPK. Micronutrients were added as foliar application while NPK as soil addition. Obtained results indicated that all treatments under investigation significantly affected all traits. The highest values of vegetative growth parameters including fresh, dry weight of bulb and total yield as well as N, P, K, Cu, Fe and Zn, beside nitrate reductase activity in onion bulb recorded with using 50% NPK as soil addition and foliar application of (Fe + Zn + Cu). NO₃-N and NO₂-Nin onion bulb also recorded the highest mean values with the untreated plant (control). The highest availability values of N, P and K in the soil after harvesting were recorded in case of the addition of Fe + Cu + Zn + 50% RD from NPK.