The effect of different nitrogen levels on yield and quality of stevia (Stevia rebaudiana bert.)

In the present work, the efficiency of different nitrogen doses (0, 50, 100, 150, and 200kg ha(-1)) on growth, yield, and quality of stevia (Stevia rebaudiana Bert.) was investigated in 2011-2013. The study was conducted in Antalya located in the Mediterranean Region of Turkey. Terra rossa type soil (LVx, FAO) characteristics of the experimental field were clay loam, with high amounts of lime (33,9%) and slightly alkaline (pH 7.7). The experiment was carried out in randomized block design with four replications. All the results were summarized as mean of three years. The highest fresh and dry biomass yields (26.75 t ha(-1) and 7.5 ha(-1), respectively) were obtained from 150kg ha(-1) N dose and followed by 100kg ha(-1) N dose (26.29 t ha(-1) and 7.24 ha(-1), respectively). Whereas the highest fresh and dry leaf yields (13.27 t ha(-1) and 3.82 t ha(-1), respectively) were realized in 100kg ha(-1) N dose. Actually, all nitrogen doses gave higher biomass and leaf yields compared to the control. On the hand, major steviol glycosides (stevioside and rebaudioside A) in the leaf were not influenced by nitrogen levels. In conclusion, 100kg ha(-1) N dose was found to be suitable for cultivation of stevia under field conditions.