بهینه‌سازی توصیه کود نیتروژن برای رقم جدید گلرنگ در دو منطقه آذربایجان‌شرقی

In order to optimized nitrogen fertilizer recommendation for a new safflower cultivar called “Padideh” an experiment was conducted in two regions of East Azerbaijan, Tikmehdash and Shabestar. Experimental design was a randomized complete blocks design arranged in factorial with three replications. The first factor was different nitrogen rates including 30, 60, 120 and 180 kg ha-1 nitrogen supplied from urea and the second factor was three times of split nitrogen application (including seed sowing, rosette and before flowering stage) at 1-0-0, 0-1-0, 1/3-1/3-1/3, 0-2/3-1/3 and 0-1/3-2/3 ratios. The results showed that, there was significant difference between the two regions in terms of studied traits so that safflower in Tikmehdash out-performed it at Shabestar. In addition, different nitrogen rates had significant effects on safflower traits. In general, increase in nitrogen rate led to increase in vegetative growth and improved yield and yield components. Furthermore, some parameters such as nitrogen agronomic efficiency, nitrogen use efficiency, nitrogen physiologic efficiency and apparent nitrogen recovery increased with increasing nitrogen application. Spliting nitrogen application showed a significant effect on some vegetative and yield related traits as well as nitrogen agronomic efficiency. Interaction between nitrogen rate and time of application was significant on plant height, seed number in capitulum, seed yield and oil yield. Safflower grain yield in Tikmehdash region using 180 kg ha-1 nitrogen and applied at rosette and prior to flowering stage was found to be greater than Shabestar.