The effect of different nitrogen doses and harvest times on the some agronomical properties of stevia (Stevia rebaudiana Bertoni) in Aydin ecological conditions

This research was carried out in 2017 in Aydın province ecological conditions. The experiment was arraged in Completely Randomized Block Design with two factors and four replications. Nitrogen fertilizer doses (0, 5, 10, 15 kg/da) harvest time (pre-flowering, full flowering and end flowering stage) were in main and sub-plot, respectively. Plant height (cm), leaf width (cm), leaf length (cm), fresh herb yield (kg/da), dry herb yield (kg/da), fresh leaf yield (kg/da), fresh leaf ratio (%), dry leaf ratio (%), dry leaf yield (kg/da) and dry matter ratio (%) were examined. According to the results of the research, the longest leaf length (4.94 cm) and leaf width (1.91 cm) were from the pre-flowering stage, while the longest plant height (52.63 cm) was from the post-flowering stage, the highest dry matter ratio (26.14%) was higher than the full flowering stage. Fresh herb yield (318.43 kg/da), dry herb yield (100.19 kg/da), fresh leaf yield (106.83 kg/da) and dry leaf yield (33.88 kg/da) were measured from the application of 15 kg/da nitrogen dose. The highest ratio of fresh leaf (54.64%) and dry leaf (59.38%) were measured from the harvested in the pre-flowering stage. In Aydın ecological conditions, the highest values were obtained from the plants harvested from the pre-flowering stage in which nitrogen dose was applied at 15 kg/da. Key Words: Stevia, Stevia rebaudiana Bertoni, Nitrogenous fertilizer, Harvest time, Yield.