Response of Stevia (Stevia rebaudiana Bertoni M) To Nitrogen and Potassium Fertilization

Abstract

Objective of this research was to obtain optimal dosages of nitrogen and potassium fertilization on growth, yield, and quality of stevia. The research was conducted using Randomized Block Design (RBD) by 3 replications, which was constructed in factorial that comprised of 2 factors. The first factor was dosage of the nitrogen with 4 (four) levels, such as: 100, 150, 200, and 250 kg N ha-1. The second factor was dosage of potassium with 3 (three) levels, such as: 75, 150, and 225 kg K2O ha-1. Result of the research showed that significant interaction between nitrogen and potassium fertilization has occurred on parameter of the plant growth, such as number of leaf, leaf area, leaf area index, and the total chlorophyll content. Separate application of nitrogen and potassium fertilization has significantly affected on the plant height, while the stomatal density was only affected by the application of nitrogen. Significant interaction between nitrogen and potassium application has occurred on plant biomass and the yield of leaf during the harvest period I, II, and total. During the period of total harvest, the fertilizing treatments of 200 kg N ha-1 and 225 kg K2O ha-1 have harvested fresh leaves and dry leaves for about 2,780 kg ha-1 and 636 kg ha-1, respectively. The increasing application of nitrogen from 100 to 250 kg N ha-1 has significantly increased the stevioside level of the stevia’s leaf linearly in accordance with the equation of Y = 0.000408 X + 0.439.