Two field experiments were conduced in Sakha Agricultural Research Station farm to investigate response of sugar beet plant var. Lola to nitrogen levels (100%, 75% and 50% of recommended dose) and/or combined microbial inoculation (Azotobacter chroococcum + Bacillus megatherium). Results showed that N-application significantly increased top and root yields, root fresh weight and sugar yield (ton/fed.), but did not significantly affect the percentages of N, P, K, -amino nitrogen, Na, sucrose, extractability, sugar extractability/plant and purity.
Microbial inoculation significantly increased top and root yields and root fresh weight, while did not significantly influence percentages of N, P, K, sucrose, sugar extracted/P or extractability, -amino nitrogen and Na.
The treatment, inoculation + 75% N gave the highest economic net return without exerting a bad effect on yield quality. Therefore, the study recommended the application of this treatment as an agricultural process for sugar beet, where it showed a positive effect on the yield and resulted in saving a lot amounts of chemical N fertilizer. The matter which is important in decreasing the deleterious effect of nitrogenous fertilizers residue on the environment.