الفهرس 
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Abstract
This thesis was carried out to study the effect of organic and bio fertilization compared with NPK fertilization and their interactions on growth, yield, chemical composition and non-caloric thermo-stable intense sweeteners yield of Stevia plant (Stevia rebaudiana) under different Egyptian soils conditions. In addition, saving some doses of mineral fertilization. Methods and results A bag experiment at the Experimental Farm of the Fac. Agric. Mansoura Univ. during the summer season of 2013. The experimental design of present study was split plot design with three replications, where soil types represent the main factor and fertilization treatments were the subplot factor. Three soil types were used as clay loam, loamy and sandy soil and six fertilization treatments were control, 100 % of recommended NPK fertilizers,50 % of recommended NPK fertilizers, biofertilizer, organic fertilizer (compost), and mixture of 50 % of recommended NPK + bio + compost. Results indicated that application of mixture, 50 %, organic and biofertilizer increased the means values of leaves, stems and shoot fresh weights. Also dry yield was of stevia plants significantly increased over the control (without fertilization). Concerning to soil types revealed that the greatest value was obtained due to growing stevia plants on clay loam soil compared to both loam and sandy soils. The greatest shoots plant fresh weight of stevia was obtained due to growing in clay loam soil. Regarding on the effects of soil, The highest value of stevioside yield in stevia leaves (2153.61 mg/bag) in clay-loam soil whereas the lowest value was (1465.71 mg/bag) with sandy soil. Conclusion : Stevia plant is concerned as unknown plant in the Egyptian countryside society and needs a lot of effort to make available to determine the optimal levels appropriate for the cultivation, production and commercialization. Through this thesis it can be concluded that the mineral fertilizer has the main role in increasing vegetative parameters while at the quality attributes of the active ingredient (stevisoide) it was found that the impact of bio-treatment and organic had the greatest influence. The treatment (50% NPK recommended + bio-fertilizer + Organic fertilzer) had most importantly effect, so we can save mineral fertilizers and study which is the optimal percentage among the 50% to 100% mineral fertilizers to save the mineral addition. Therefore, reasonably using of organic manure can improve quality and yield of the Stevia rebaudiana Bertoni, perfect the soil structure and protect the environment.