effects of different irrigation regimes on fruit production, oil quality, water use efficiency and agronomic nitrogen use efficiency of pumpkin

effect of different irrigation regimes and nitrogen fertilizer on percentage of grain fatty acids, yield, water and nitrogen use efficiency of pumpkin was studies as split plot based on complete randomized block design with three replications in growing season of 2013. irrigation treatments (320, 420, 600 and 900 mm ha-1) were se as main plots and nitrogen fertilizer (0, 130, 260, 390 and 520 kg urea ha-1) were allocated in subplots. the effect of irrigation and nitrogen on all traits was significant. also, interaction of irrigation × nitrogen had significant effect on all traits except wue and nue. the highest values of linoleic fatty acid (33.99%), fruit yield (4.40 kg m-2), grain yield (1.53 kg m-2) and agronomic nitrogen use efficiency (32.27 kg fruit/kg urea) were achieved at consumption of 600 mm water ha-1 and application of 390 kg urea ha-1. the highest water use efficiency for fruit and grain yield; 56.61 and 1.10 kg mm-1, were revealed at 600 mm irrigation water ha-1. between nitrogen levels, maximum and minimum wue for fruit and grain yield were achieved at 390 kg urea and non application of urea treatments, respectively. also, maximum agronomic nitrogen efficiency belonged to 390 kg urea and minimum this trait with 33 reductions was revealed at 520 kg urea. based on the results of this research and with considering of water and nitrogen use efficiency, irrigation of pumpkin plants with 600 mm water ha-1 and consumption of 390 kg urea ha-1 was identified as a suitable treatment.