The effect of soil application of yeast (Saccharomycec cerevicea) each separately or in combination with foliar spray of either citric or ascorbic acid on some growth characters, yield, and yield components as well as on the microbial populations in the rhizosphere of barley plants was investigated in a field experiment. Among all treatments, plants fertilized with recommended doses of N fertilizer scored the highest grain yield, straw yield, spike length, weight of grains per spike, 1000-grains weight and N-content in straw and grains. Heavy inoculation of soil with yeast separately, or in combination with foliar spray of citric acid and\or ascorbic acid gave higher values in plant height, grain yield, number of grains per spike, 1000-grains weight compared to those fertilized with half dose of N-fertilizer only. When yeast was applied as a soil inoculant combined with foliar spray of ascorbic acid, their effect on plant height, straw and grain yields, N content in straw and grains was higher than those inoculated with yeast along with foliar spray of citric acid. The total numbers of bacteria, fungi and actinomycetes were increased by soil application of yeast separately or in presence of foliar spray of citric acid and\or ascorbic acid as compared to the plants fertilized with either recommended or half dose of N fertilizer especially at tillering stage. When yeast was combined with foliar spray of ascorbic acid, their combination gave the highest number of bacteria compared to the other tested treatments. As usual the lowest number of bacteria, fungi and actinomycetes was recorded in plants fertilized with ½ dose of the recommended N fertilizer. Generally these results suggest that the heavy use of yeast as a source of nutrients and plant growth hormones along with foliar sprays of either citric or ascorbic acid might be considered  as an alternative  substitute of half dose of recommended N-fertilizer applied for barley crop.