Basma R. A. Rashwan1 and H. Ferweez2 ( 2017). Effect of Mineral Nitrogen Fertilization and Compost on Stevia Yield and its ProfitabilityJ.Soil Sci. and Agric. Eng., Mansoura Univ., Vol. 8 (6): 215 - 222 ,
Abstract: Stevia (Stevia rebaudiana Bertoni ) was recently introduced to Egyptian agriculture in order to produce a natural sweetener (Steviol glycosides ) instead of sugar (Sucrose) to cover some of the lack of sugar production, which reached annually about 0.8 million ton. So, a field experiment was carried out at Mallawi Agriculture Research Station , Minia Governorate , Egypt, during two successive seasons (2014 and 2015) to study the effect of different levels of mineral N fertilization and compost on yield and its quality of stevia (Stevia rebaudiana Bertoni) under Middle Egypt conditions. The experimental design was a split plot in three replicates and the main plot were devoted N fertilizer levels ( 40, 60 and 80 kg N fed-1) while compost levels (0, 3 and 6 ton fed-1) were allocated in the sub plot. The obtained results revealed that N fertilizer level and/or compost level had a significant effect on plant height (cm) , fresh and dry leaves weight (g plant-1) , N, P& K contents of stevia leaves and N uptake kg fed-1, dry leaves yield kg fed-1 , stevioside (St %), rebaudioside A (Rb%), stevioside yield (kg/fed) and rebaudioside A yield (kg fed-1), the remained nutrients ( N,P & K (ppm) and OM % ) in the soil post-harvest of stevia in two growing seasons, except P% of leaf in the 2nd season for N fertilization. A significant interaction was scored between N fertilizer level and compost rate with regard to plant height (cm) , fresh and dry leaves weight (g plant-1) , N % of stevia leaves and N uptake kg fed-1 , dry leaves yield kg fed-1 , stevioside (St %), rebaudioside A (Rb%), stevioside yield (kg fed-1) and rebaudioside A yield (kg fed-1) of stevia in the two growing seasons. From the present study , it may be concluded that the application of 60 kg mineral N fertilizer + 6.0 ton compost fed-1 was the best treatment for improving the yield and quality of stevia and is advisable to achieve the highest values of rebaudioside A (298.99 and 297.74 kg fed-1) ,and net profit of stevia.
Keywords: (Stevia, N fertilizer, compost, stevioside%, rabaudioside A)
