الفهرس 
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Abstract
Objectives: The main objective of the study is to develop the response of sweet potato plants to mineral and bio-fertilization on vegetative growth, yield and its components, chemical and quality parameters.Methodology & Results: The experiments were set out in split plots experiment in randomized complete block design (RCBD) with three replicates in two seasons. The experiment contained 15 treatments including, 3 levels of NPK fertilizers as soil application and 5 bio-stimulants as soil and foliar application treatments. The main plots were contained three levels of mineral NPK fertilizers as soil application as follow: 100%, 50% and 0 % NPK fertilizers of the recommended doses, The sub plots were devoted to four application treatments of bio-stimulants added to control treatment as follow: Spraying with tap water (Control treatments),Soil application with EM at the rate of 2 ml/1L, Microbial mixture consist of Azotobacter chroococcum bacteria, Bacillus circulans bacteria and Arbuscular Mycorrhiza fungi, it was added to the soil surface around the plants at the rate of 1L /20L, Yeast was sprayed on vegetative growth at concentration of 10 g/1L, Seaweed extract was applied as foliar spraying at the rate of 1 g/1L. the results show that the best interaction between mineral and bio- fertilization was 50% NPK and EM, it can decrease nitrate and nitrite content, costs, pollution environment. Conclusion Under the present work conditions, it could be concluded that using of any bio stimulants (EM, Microbial mix, yeast and SWE) are possible to enhance the vegetative growth and consequently yield and quality of sweet potato because of the soil improvement which reflected on the availability of mineral nutrients absorption. Among the interaction treatments, it could be concluded with that 50% NPK from the recommended rates plus EM applied at the rate of 2ml/L three times to the soil which gave 44% yield increment relative to the control, reduce chemical NPK fertilization, decrease NO3 and NO2, improve tuberous roots quality parameters, reduce environment pollution and costs and greatly safe for human. In case of cultivation legume before the cultivation of sweet potato as well as adding organic fertilizer at the rate of 20m3/fed during the soil preparation before the cultivation of sweet potato, thus the organic matter % were raised to 4.23 and 3.75 in the both seasons respectively. It is possible to add Effective microorganisms without any chemical fertilizers (0% NPK+ EM) which increased yield by 27.6%, gave the least NO3 and NO2 content. In general, the results show that using any bio-stimulants with reduction of mineral fertilizers (N, P and K) amounts to 50% from recommended doses or with bio-stimulants alone without adding any mineral fertilizers (0% NPK) in case of fertilite soil which contain a high percentage of organic matter achieve the goal of the present experiment under Damietta circumstances, Egypt.