الفهرس 
Effect of weed competitionOnly 14 pages are availabe for public view
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Abstract
Weed species under investigation
differed in their competing abilities against sugar beet plant, and
consequently in their impairment on aerial and root growth criteria. It is
possible to produce tentative ranking of competitive abilities of the seven
weed species under investigation as following: high competitive: wild
beet, canarygrass, and bermuda-grass; medium competitive: dock weed
and tooth pick and poorli competitive: lambsquarters and bindweed.
Moreover, weed interference reduced to different extents T.S.S. %,
sucrose % and nutrient (N, K and Na) concentrations in sugar beet roots
than the control.
Sugar beet exerted also a drastic reductions in growth indices of
associated weed species. Aerial parts of bindweed followed by wild beet
and sub-soil parts of dock weed, wild beet and lambsquarters were the
most sensitive weed parts to the harmful impacts of such interference.
Contrarily, canarygrass and tooth pick can withstand competition of sugar
beet without any significant reduction in their growth.
Weeds can also affect sugar beet plant through the production of
teletoxic substances. Aqueous leachates of weed roots inhibited
germination and seedling development of sugar beet seedlings. Decayed weed roots in soil decreased significantly growth, yield and quality
parameters of sugar beet plant. Bermuda-grass. canarygrass and wild beet
were the greatest dangerous weeds in weed interference trial. However the
same weed species imposed also the strengther allelopathic effect on sugar
beet plant. Meaningly, alielopathy constructed a significant component in
weed-crop interference of sugar beet.
Key