Pot experiments were conducted during two successive seasons of 2019 and 2020 at the Fac. of Agric., Minia Univ. to investigate effects of four application rates of compost (0, 1, 2 and 3%) (w/w) and six treatments of bio-fertilizers and/or mineral NPK fertilization (control, Azotobacter chroococcum + Bacillus circulans, Azotobacter chroococcum + Bacillus megaterium, mixture of bio., mixture of bio. + 75% NPK and 100% NPK) on vegetative criteria, accumulation of bioactive compounds (phenolic compounds and flavonoids) through improving plant's secondary metabolism and antimicrobial activity of methanolic and ethanolic extracts of Populus alba.  All compost treatments significantly improved all transplant vegetative growth parameters such as plant height, diameter, aerial part fresh and dry weights, main root length and roots fresh and dry weights, as well as, total chlorophylls and NPK% as compared to control. Biofertilizers and/or mineral NPK fertilization treatments significantly increased all the previous traits, the mixture of three species of bacteria plus 75% NPK followed by mineral full dose of NPK treatments were the most effective than other used treatments. The highest values were obtained when Populus alba transplants were grown in sandy soil contained 3% compost plus inoculation with three species of bacteria plus 75% NPK or compost at 3% plus 100 % NPK and these two treatments give the highest values of phenolic compounds in the methanolic and ethanolic extracts. This research confirmed that poplar is a promising wooden tree to be grown on sandy soils for timber production in Egypt, woody products and bioactive compounds.