effect of different biofertilizers and irrigation closed time on some agronomic characteristics of sugar beet (beta vulgaris l.)

objective: a field experiment was conducted at dorud region, iran, during 2013. the aim of this research  was study on effect of different biofertilizers and irrigation closed time on some agronomic characteristics of sugar beet (beta vulgaris l.). methods: the experimental design was factorial based on rcbd with three replications. treatments were three irrigation closed time [oct-6 (a1), oct-13 (a2) and oct -21 (a3)] and three nitrogen biofrtilizers [nitroksin (b1), nitrokara (b2), biozar (b3) and control (b4)]. after treatments 3m2 in each plot harvested for leaf and root yield measurement. k%, na% and n% were determined by betalizer machine in isfahan sugar beet factory. results: results showed that, the effect of all treatments on root yield was significant but all treatments were not significant on fresh leaf yield. effect of different biofertilizers were significant on k% and n% and other treatment were not significant on them. the effect of any treatment was not significant on na%. among the nitrogen biofertilizers, nitroksin and biozar treatments has the highest k% and nitrokara treatment has the lowest k% and nitroksin treatment has the highest n% and nitrokara treatment has the lowest n% and the differences of them were significant. in final we reviled that application of different biofertilizers and different irrigation closed time reviled that among the all treatment highest root yield was belonged at application of biozar in oct-13 irrigation closed time and minimum root yield was belonged at application of nitrokara in oct-21 irrigation closed time.