qualitative characteristics of sugar beet as affected by different broadleaf herbicides combinations

Several herbicides are registered for selective weed control in sugar beet; however, no single chemical herbicide can control all weeds in beet fields. frequently, two or more herbicides may have to be combined sequentially or as tank mixed to achieve adequate broadspectrum weed control. in order to evaluate the effects of some combinations of broadleaf herbicides on sugar beet yield and quality, a field experiment was conducted in randomized complete block design with three replications at miandoaab agricultural research station during 2009-2010 growing season. the results showed that weed competition decreased root yield up to 84%. the maximum root yield (73.66 tha^-1) was obtained from 4.5 kgha1metamitron application at 2to 4leaf stage and the minimum root yield was obtained in the control (20.66tha^-1). the herbicide treatments had a significant effect on white sugar content so that the highest white sugar yield was achieved from bettanal progress am herbicide (10.9 tha^-1) and the lowest white sugar yield was found in control treatment (1.49 tha^-1). the lowest sodium, potassium, aminonitrogen as well as molasses content were obtained from phenmedipham + desmedipham + ethofumesate and the highest value for the above parameters was observed in control treatment. generally, weed competition led to decreasing root yield and sugar content and treatment bettanal progress am herbicide was recommended to control broadleaf weeds.