This study aimed at investigating the effects of irrigation with saline water and nitrogen fertilization practices (rates and distribution frequencies) on maize production, using 15N tracer technique. Data indicated that germination stage is more tolerant to salinity level than the seedling one. The gradual increments in the irrigation salinity level up to 12 dS/m did not stop germination but delayed the mean time of germination. Oppositely, the seedlings showed higher reductions in their growing parameters even at low levels of water salinity (6-8 dS/m). 15N analysis data show that, nitrogen derived from fertilizer as well as that derived from soil, the nitrogen accumulation in the different plant components and the nitrogen use efficiency were affected not only by the N application rate and its distribution during the cropping cycle but equally by the salinity level of the irrigation water.
