Organic manures and bio-fertilizers effectively improve yield and quality of stevia (Stevia rebaudiana)

Abstract: The influence of different organic manures, bio-fertilizers and green manures on growth, yield and glycoside content of stevia (Stevia rebaudiana) was studied over a period of three years (2004-2007). Various organic supplements viz., farm yard manure (15 and 25 t ha^-1), vermicompost (1 and 2 t ha^-1), neem cake (0.5 and 1 t ha^-1) and bio-fertilizers viz., Azospirillum, phosphorus solubilizing bacteria and VAM (each @ 0 and 10 kg ha^-1) were applied. The results of eleven harvests revealed that all the growth parameters viz., plant height, number of branches and plant spread were influenced by various organics and bio-fertilizers and showed variation from season to season (harvest to harvest) and plants responses did not followed a definite trend. Dry leaf yield during first (6.16 t ha^-1) and second year (4.34 t ha^-1) of cropping was maximum with the treatment receiving FYM (25 t ha^-1) + vermicompost (2 t ha^-1) + neem cake (1 t ha^-1) + bio-fertilizers (10 kg ha^-1) and differed significantly. However, in third year of cropping the treatments had no significant influence on the dry leaf yield. Both the glycosides i.e., stevioside (7.8 %) and rebaudioside content (3.4 %), and glycoside yield were also highest in the above said treatment.