The Effect of Irrigation and Nitrogen Fertilizer on Morphological Characteristics and Essential Oil Percentage and Yield of Dill (Anethum graveolens L.)

In order to investigate the effect of irrigation and nitrogen fertilizer on morphological characteristics and essential oil percentage and yield of dill, this research was performed in 1389 in Agricultural Research Farm of the University of Tabriz. The experiment was carried out as split plot based on randomized complete block design with three replications. Irrigation treatments (irrigation after 70, 100, 130 mm evaporation from class A pan) and nitrogen levels (0, 40, 80, 120 kg/ha) were allocated to main and sub-plots, respectively. The results showed that the irrigation treatments had significant effect on secondary branches number, stem weight. Although stem diameter and flower weight was affected significantly by nitrogen fertilizer amounts. Maximum number of secondary branches and stem weight were observed in irrigation after 130 mm evaporation from class A pan) and control treatments respectively. Largest stem diameter were obtained by 120 and 80 kgN/ha respectively. Irrigation after 130 mm evaporation and 80kgN/ha and irrigation after 70 mm evaporation and 0kgN/ha produced the highest and lowest flower weight, respectively. The highest essential oil percentage obtained from irrigation after 70 mm evaporation. As there was a positive relationship between flower yield and essential oil percentage, for producing the highest essential oil percentage, application of 40 kg/ha nitrogen is suitable. So reducing water supply from 70 to 130 mm evaporation had no significant effect on essential oil yield, it seems that produce the higher essential oil content from dill, is possible with remarkable decreasing of water consumption.