Various methods for determining the critical period of weed competition to sugar beet [electronic resource].

Includes references.

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 inducted 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.l 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.

Summary in Arabic.

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