Effect of Irrigation and Nitrogen Fertilizing on Phenology, Grain Yield and Oil of Pumpkin (Cucurbita pepo L.) in Hamadan Region

 
Abstract
          The aim of this research was to evaluate the effects of irrigation interval and nitrogen fertilizer on phenology, yield and seed quality of pumpkin. Experiment was laid out as a split plat based on randomized complete block design with three replications at the Bu-Ali Sina University in growing season of 2013. The main plots included irrigation intervals at four levels of I₁: 6 days irrigation interval, I₂: 9 days irrigation interval, I₃: 12 days irrigation interval, and I₄: 15 days irrigation interval and sub plots included different nitrogen levels of N₀: 0 kg N/ha, N₁: 60 kg N/ha, N₂: 120 kg N/ha, N₃: 180 kg N/ha,N₄: 240 kg N/ha from the source of urea fertilizer. In the present research traits of days to flowering, days to fruiting days to maturity, seed number/fruit, 100-seed weight, grain yield, oil percent and oil yield were evaluated. The effect of irrigation interval and nitrogen on all traits was significant. Effect of treatments interaction was also significant on all traits except number of seeds/fruit and oil yield. The highest values for days to flowering and days to maturity were achieved at I₂N₃ treatment. Also, maximum and minimum values for 100-seed weight as well as grain yield were achieved at I₂N₃ and I₄N₀ treatments, respectively. I₂N₃ had no significant difference with treatments of I₁N₃، I₁N₄ and I₂N₄. In comparison with I₂N₃ treatment, the lowest values for days to flowering, 100-seed weight and grain yield with reduction of 35, 68 and 73%, respectively, were revealed at I₄N₀ treatment. The highest percent (46.81) and oil yield (32.90 g/m²) with no difference with I₂ treatment, revealed at I₁ treatment. In comparison with I₂ treatment, I₄ treatment reduced 52.50% oil yield. Also, the highest oil yield (27.50 g/m²) was achieved at N₃ treatment. Therefore, in order to optimizing water and nitrogen consumption in pumpkin production, I₁N₃ treatment was identified suitable treatment.