Effect of Nitrogen and Salinity on Irrigation Water Yield and Productivity at Different Soil Moisture Levels

The water crisis coupling with the soil salinization have made the agricultural sector facing serious challenges. This study aims to investigate the effects of nitrogen fertilizer levels on yield and water use efficiency of autumn Canola (Brassica Napus) under drought and salinity stress conditions in Lake Urmia basin. This research has been conducted as factorial based on randomized complete blocks design with three replications at the research farm of Department of Water Engineering, Urmia University. Irrigation as first factor have been applied at three levels including 50%, 75% and 100% of field capacity, salinity stress as second factor have been applied at three levels including irrigation without salinity, with 7 and 14 dS/m saline water, and nitrogen as third factor have been applied in 60, 120 and 180 kg/hectare. The highest grain yield (4.45 tons/hectare) have been achieved in field capacity irrigation, nitrogen 180 kg/hectare without salinity stress treatments and the lowest rain yield (0.59 tons/hectare) have been achieved in up to 50% of field capacity irrigation, 60 kg/hectare pure nitrogen and 14 dS/m salinity treatments. The highest value of this index (8.5 tons/hectare) have been achieved in field capacity irrigation, nitrogen 180 kg/hectare without salinity stress treatments and the lowest rain yield (1.2 tons/hectare) have been achieved in up to 50% of field capacity irrigation, 60 kg/hectare pure nitrogen and 14 dS/m salinity treatments According to the results, the use of nitrogen fertilizer lead to greatly amend the effects of salinity stress. Among the measured parameters, plant height is the most resistant trait with the least variation in stress conditions. Increasing salinity leads to reduce the water use efficiency.