Effect of environmentally friendly nutrition supply on stevia (Stevia rebaudiana B.) production

Abstract

The experiment was carried out on raised bed (3 rows) with 33 cm row distance and 25 cm between the plants and 24 plant m-2 density. The plantation was prepared on 28 May, 2015 with about 10 cm high transplants. The soil surface was mulched with wooden chips (5 cm layer). The aim was to evaluate the environmentally friendly fertilizers (Dudarit - 150 g m-2, Sprintalga - 0.04% concentration four times 200 mL per plant). During the vegetation period pruning was applied at 30 cm plant height at the 4th double leaf from the soil surface and two cuttings (13 Aug and 29 Sept). By evaluating the effect of treatment on the leaf surface and chlorophyll content, statistically significant results were not found. Higher SPAD (relative chlorophyll content) value was measured in the middle of the growing period compared to the end of the vegetation when the plants were older and the temperature started to decrease. The positive effect of Dudarit and Sprintalga was clear on the plant height and biomass production. The dried herb yield was higher (4 kg m-2) on treated plots comparing to control (3 kg m-2). Although increased photosynthetic intensity was not detected on treated plots, the plantation showed greater vitality and side shoot improvement to control plots. Under our circumstances, the environmentally friendly fertilization (Dudarit and Sprintalga) has increased the dried leaves yield with 20% by similar stevioside and rebaudioside-A content.