The present work was carried out during 2019 and 2020 seasons at the Experimental Lathe-house, Fac. Tech.& Develop., Zagazig Univ., to evaluate to what extent can use humic acid and/ or active dry yeast applications instead of/ or compensate the NPK chemical fertilization for enhancing vegetative growth, herb yield and essential oil yield. The obtained results can be summarized as follows: The treatments of 2.5 g NPK/ pot, 2.5 g/ L Humic acid + 8.0 g/ L dry yeast extract, and the interaction of

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... the treatment of 2.5 g NPK/ pot, with 2.5 g/ L humic acid + 8.0 g/ L dry yeast extract, being the most effective on vegetative growth, oil yield and the chemical constituents of volatile oils of sweet basil plants, followed by the treatments of 2.5 g NPK/ pot , with 12 g/ L dry yeast extract , and 2.5 g NPK/ pot , with 5 g/ L Humic acid , respectively, in most cases , in the two times of cutting of this study. Conclusively, from this study and the obtained results, it can be concluded that the medium level of NPK at 2.5 g / pot, 2.5 g/l Humic acid + 8.0 g/l dry yeast, and its interaction were recorded the highest values on plant growth characters, chemical contents, pigments, oil yield, and chemical constituents of volatile oils. As well as, the suitable rate of humic acid and dry yeast extract can compensate the high level of NPK doses.