Influence of different weed species on sugar beet yield

The influence of different weed species (natural infestation on herbicide-t reated field) on the yield and quality were studied in sugar beet stands co mpared to the weedless plots. The density of weeds was 2-5/m(2). Chenopodiu m album L., Abutilon theophrasti Medic. and Amaranthus blitoides S. Watson reduced the yield of sugar beet [t/ha] by 20-30%, while Ambrosia artemisiif olia L. decreased the beet yield by 40-50%. The sugar content (digestion %) was also reduced, by 4-7% in the case of Ch enopodium album L., Abutilon theophrasti Medic. and Amaranthus blitoides S. , but by 13-15% under the influence of Ambrosia artemisiifolia L. The sugar yields, calculated from the above data, were between 9157-9872 kg /ha on the weedless plots. Plots covered with Chenopodium album L., Abutilo n theophrasti Medic. and Amaranthus blitoides S. Watson produced 65-75% of the yield relative to the weedless plot, while Ambrosia artemisiifolia L. c over caused a 50% sugar yield loss. There was no significant relation ship between the content of harmful, non- sugar material (K, Na and alpha -amino N) in the sugar beet samples and the presence of weeds. The trial proved that weediness in the sugar beet stand has a significant i nfluence on the yield (beet yield, digestion and sugar yield). Chenopodium album L., Abutilon theophrasti Medic. and Amaranthus blitoides S. Watson re duced the yield to nearly the same extent, but the damage caused by Ambrosi n artemisiifolia L. surpassed that of all three weeds.