evaluation of quantity and quality of sugar beet under drip and furrow irrigation methods in north of khuzestan

drip irrigation is the most efficient technique known for improving irrigation water management. a two-year study was conducted to determine the effects of drip and furrow irrigation methods on yield and quality of sugar beet in north of khuzestan. in the first year, the experimental design was a completely randomized block design with three replications. treatments were, three drip irrigation levels (50%, 75%, 100% and 125% volume of water requirement for sugar beet) and one furrow irrigation. in the second year four drip irrigation treatments (50%, 75%, or 100% volume of water requirement for sugar beet), and two row spacing treatments (90 and 120 cm) were conducted in a split-plot design with three replications. a furrow irrigation treatment (row space = 90 cm) was also included in each replication. the treatments were arranged in a split-plot design with three replications. the results of two years showed significant differences (at 5%) in yield of root and sugar among different levels of drip irrigation and furrow irrigation treatment. water use efficiencies of root and sugar were also significantly different (at 1%) among the treatments. in contrast, there was no significant difference among treatments in qualitative traits of root. higher yield of root and sugar were obtained in furrow irrigation treatment (83.5 and 9.34 t/ha respectively), while lower root and sugar yield (71.16 and 8.73 t/ha respectively) were produced in drip-irrigation treatment with 50% level. this treatment had also the maximum water use efficiencies of root and sugar (18.3 and 2.29 kg* m-3 water respectively). plants in the furrow irrigation treatment had minimum water use efficiencies of root and sugar (6.14 and 0.69 kg* m-3 water respectively).  in the second year of experiment the quantitative and qualitative traits did not affect by row spacing treatments.