1) Field Crop Res. Inst. A.R.C, Egypt. (2) Soil, Water and Environment Res. Inst.; ARC, Egypt. ABSTRACT: Two field experiments were conducted at Nubaria Agricultural Research Station in two successive seasons Ammonium nitrate and N2 = Ammonia gas )on wheat biological, grain yields, yield components, water requirements and productivity of water. Results showed that, biological and grain yields, plant height, number of spikes /m 2 , number of kernels / spike and1000 kernels weight were

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... affected by the interaction irrigation, nitrogen source and cultivar in both seasons. The highest values of biological and grain yields were 24.333 and 7.500 ton.ha -1 in the first season respectively, while in the second season, values were 26.333 and 9.500 ton.ha -1 ,which obtained by irrigation with water equals to 100% of ETc, fertilization by gas ammonia with cultivarSids12 (I3 N2 V2). The total applied irrigation water for I3 irrigation were 37.0 and 40.1 cm in both seasons, respectively. The highest values of productivity of irrigation water (PIW) were 2.00 and 2.62kg.m 3 , in the first and second seasons, respectively.