Influence of bio-fertilizers on the availability of nutrients (N, P and K) in soil in relation to growth and yield of Stevia rebaudiana grown in South India

Summary: A field experiment was conducted at Ripponpet (Dist. Karnataka), India in an acidic soil (pH 6.10) to study the response of Stevia plant by the application of bio-fertilizers. The results showed the amount of available nitrogen (N), phosphorus (P) and potassium (K) contents in soil have been found to increase significantly up to third month and thereafter, the amount of the same decreased with the progress of the plant growth up to sixth month irrespective of treatments. However, the results further envisaged that the total yield of fresh biomass has been recorded an increase up to sixth month, being highest in the combined application of bio-fertilizers over that of their corresponding sole applications. The percent increase of bio-mass yield was recorded highest (22.14%) in the treatment when all the bio-fertilizers were applied together. Industrial relevance: The demand of Stevia is increasing widely due to its non caloric nature and usages as sugar supplement. The leaves are having commercial importance due to presence of di-terpene sweet glycosides which are 300-400 times sweeter than sugar without any side effects. The plant was domesticated in India in last 20th century from the wide source. So there is a need to set up certain protocols for cultivation of Stevia in various soil conditions so that farmers can be benefited by selling, and industries also can get healthy leaves throughout the year for isolate the active components and can formulate economical market products.