It is well established that sugar content of sugar beet increases as the plant reaches the biological maturity stage. This means that the sugar beet plant must be left in the field to complete its growth. Farmers are usually concerned with the highest yield of sugar beet roots regardless of their content of sugar, but sugar-processing companies are concerned mainly with the amount of sugar extracted from a certain weight of roots, in addition to the purity of the sugary juice. Farmers normally receives the price of their sugar beat crop based on the sugar content of the crop. Thus, in this type of farming, biological control is a worldwide-procedure. Biological maturity depends on ways of yield formation and a close control of the mechanisms of forming yield components (no. of roots / unit area; average root weigh; average sugar content) which require a detailed study of the characters of the grown cultivar and the overall conditions of the growing area. Results showed that harvesting of sugar beet sown in fall season befor the plant completes it’s growing cycle (in June) results in a big yield in addition to a reduction in sugar content in the roots which inturn results in a big loss in the national economy. Results indicated that delaying date of harvest up to ١٨th of July markedly increased root and sugar yield as well as sugar content in the beet roots. Increasing nitrogen rate up to ٤٠٠ kg / ha resulted in a marked increase in root and sugar yield / ha . On the other hand, sucrose content gradually decreased with excess nitrogen. Higher plant density (more than ١٠٠,٠٠٠ plants /ha) enforce for late harvesting in comparison with other densities for at least ١٠ days to obtain high yield of roots and sugar.