Effect of Mineral Nitrogen Fertilization and Compost on Stevia Yield and its Profitability.

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 2 nd 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.

Response of Stevia (Stevia Rebaudiana L.) to Biogas Fertilizer and Natural Extracts Under South Sinai Conditions

“…The results were in agreement with (Zaman et al, 2018) (Liu et al, 2011) (Rashwan andFerweez, 2017) where the use of organic fertilizer improved the productivity and quality of stevia plants compared to chemical fertilizer, either by using organic fertilizer with half the dose of chemical fertilizer, which significantly affected the plant content of both stevioside and rebaudioside A., which led to obtaining the highest percentage of stevioside and the total glycosides. The increase in the total content of stevioside and rebaudioside may be due to the use of Azolla extract, which led to an increase in the leaf area, including enhancing the utilization of light energy and increasing the plant's chlorophyll content (Maswada et al, 2021) and enhancing the process of photosynthesis, which enhances the production of stevioside and rebaudioside.…”

“…Steviol glycosides with a superior taste are being investigated to generate sweeteners with a sensory profile that is closer to sucrose. The industry also uses rebaudioside A., which is now widely used (Rashwan and Ferweez, 2017). The ratio of rebaudioside A., to stevioside is the accepted measure of sweetness quality; the more rebaudioside A., the better.…”