Two trials were carried out at the Experimental Station farm of Desert Research Center, Teggzerty from Siwa Oasis, Matroh Governorate during the two summer seasons, 2015 and 2016. Trials were performed to study response of two maize hybrids.(Single hybrid 131 and Triple hybrid 329) to organic manure (OM) levels (15 and 30 m3/fed.) and five combinations between mineral and nano nitrogen (N) fertilizers: 1)100% mineral N from the recommended dose (120 kg N/fed.), 2)75% mineral + 25% nano N fertilizers, 3)50% mineral + 50% nano N fertilizers, 4)25% mineral + 75% nano N fertilizers, 5)100% nano N as the recommended rate (500 ppm as foliar application). Mineral N rates were added in three equal doses, with foliar application by nano N rates, after 30, 45 and 60 days from sowing. Treatments, included twenty treatments, was laid out in a splilt-split plot design, with three replicates, OM levels were arranged in the main plots, maize cvs. were allocated in the sub plots, and mineral nano N fertilizer treatments were assigned in the sub-sub plots. At harvest the following characters were recorded, plant height (cm), number of rows/ear, ear length (cm), ear diameter (cm), number of grains/row, 100-grain weight (g), ear weight (ton/fed), grain, straw and biological yields (ton/ fed), shelling (%) and harvest index(%). Results indicated that increasing OM levels significantly increased ear length harvest index and protein content (%), in the 2nd season only, triple hybrid gave the maximum values of all pa
rameters, except no. of rows/ear and harvest index, in the 1st season, and 100-grain weight and carbohydrate (%), in both seasons, which had no significant difference with single hybrid in the most cases. Concerning with the effect of mineral and nano N, all parameters, except carbohydrate (%), were increased with increasing mineral N (%) and/or with decreasing nano N (%). Fertilized maize crop by mineral N at 100% or 75% plus 25% nano N fertilizer gave the maximum values of plant ht., no. of rows/ear, ear length and diameter, no. of grains/row, 100-grain wt.,ear weight, grain, straw and biological yields, shelling (%), protein (%), protein yield and harvest index in both seasons. However, fertilized maize crop by nano N at 100% produced the highest value of carbohydrate content (%) in two seasons. Results suggested that selected triple maize hybrid cv. (329), at 30 m3 OM, with 100% mineral N (120 kg N/fed.) or with 75% mineral N (90 kg N/fed.) plus 25% nano N (125 ppm as foliar application) fertilizers could be utilized for attaining the maximal improvement in farmer income by increasing the maize yield under saline conditions at Siwa Oasis, Egypt.