Effect of Deficit Irrigation and Different Nitrogen Levels on Wheat Yield and Water Productivity (Case Study: Khorramabad)

Due to the importance of irrigation management and optimum use of fertilizer in each region, a factorial experiment based on randomized complete block design was conducted to investigate the effect of different irrigation and fertilizer levels on yield and water productivity of autumn wheat (Chamran-2) in Khorramabad. Totally 27 plots including three irrigation levels (100%, 75% and 50% of water requirement), three fertilizer levels (100, 150 and 200 kg ha-1) and three replications were used in the research farm of the Faculty of Agriculture and Natural Resources of Lorestan University. In this study, grain yield, biological yield, thousand seed weight, pod length, plant height, irrigation water productivity (grain yield and biological yield) and rain water productivity (grain yield and biological yield) were investigated. The results showed that the highest amount of traits were obtained in I100N200 treatment, so that the grain yield and biological yield were measured to be 3407/41 and 11097/51 kg ha-1, respectively. Also, the lowest amounts of grain yield and biological yield were observed in I50N100 treatment with 45.65 and 32.60% reduction in yield, respectively, as compared to full irrigation treatment. Interaction of water stress and nitrogen in all irrigation treatments showed by increasing nitrogen fertilizer up to 200 kg ha-1, the grain yield and biological yield increased. The results also showed that the interaction of irrigation and nitrogen fertilizer treatments on irrigation water productivity (grain yield) and rain water productivity (grain and biological yield) is significant at 1% level. The I50N200 treatment with 3.24 kg m-3 (grain yield) and 10.78 kg m-3 (biological yield) had the highest irrigation water productivity.