Various methods for determination critical period of weed competition with sugar beet

Abstract: Sugar beet (Beta vulgaris L.) crop suffer strongly from weed competition, so estimation of the critical period of weed control is very important for planning weed control strategies. For this purpose, an experiment was carried out at Mallawy Agric. Res. Station, ARC during 2009/2010 and 2010/2011 winter seasons in sugar beet. The experiment included 14 treatments of weed competition which seven of them weed – free period at 2, 4, 6, 8, 10, 12 weeks after emergence (WAE) and weed free all season and seven treatments of weed competition at 2, 4, 6, 8, 10, 12 (WAE) and weed competition for all seasons. Results of the treatments effect on weeds and sugar beet crop were used to determine the critical period of weed competition to sugar beet by using ANOVA, regression models, classical biological and economic approach.
The obtained results showed that the maximum root yield (ton/fed.) & Sugar yield (ton/fed) losses due to sugar beet-weed competition in the whole season were 86.8 & 87.1 and 84.6 & 86.3 percentage from weed free plot due to weed infestation by 10.0 and 9.7 ton/fed. in 2009/2010 and 2010/2011 seasons, respectively. The relationship between sugar beet root yield (ton/fed), sugar yield (ton/fed) and weed free, weed competition periods were studied using linear, quadratic and logistic functions. The relationship between dry weight of total weed g/m2 at end growing season and period of weed free was significantly negative and prediction equation with R2 value 84.9%, but, the relationship between this traits were positive and prediction equation with R2 value 18.3% without any significant between all weed competition treatments.
To maintain 95% of maximum root and sugar yields of sugar beet the maximum time allowed to let weeds grow after crop emergence is 0.86 weeks. The same level could be achieved if the crop kept free from weeds until at least 15.1 weeks after sugar beet emergence. Results showed that the critical period of sugar beet/weeds competition between 2 to 12 weeks after emergence and weed control strategies should be used to prevent weed competition in this period to maintain maximum sugar beet yields. The early and late income period threshold was estimated by 4- 10 weeks after emergence as the time interval when the gross income of sugar beet yields are higher than the total cost include cost of weed control treatments.
URL
Publication year 2012
Pages 515-530
Organization Name
serial title Egypt, J. Agric. Res.,
Author(s) from ARC
External authors (outside ARC)
    أنعام حلمي جلال قسم المحاصيل-كلية الزراعة-جامعة أسيوط
    فتحي محمد فتحي عبد المتجلي قسم المحاصيل-كلية الزراعة-جامعة أسيوط
AGROVOC
TERMS		 Plant competition. Sugarbeet. Weed control.
Proposed Agrovoc Beta vulgaris L.;critical period;
Publication Type Conference/Workshop
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