Critical period of weed interference in irrigated common bean (Phaseolus vulgaris L.) in Dongola area

Abstract

This study was conducted at the Faculty of Agricultural Sciences farm, University of Dongola, El Selaim, during 2010/2011 and 2011/2012 winter seasons to investigate common bean (Phaseolus vulgaris L.) yield loss due to weeds and identify the critical period for weed control. Common bean was sown on 23 November in both seasons. A set of weeding regimes comprising of 12 treatments was arranged in randomized complete block design with four replicates. The crop was kept weed-free for 2, 4, 6, 8 or 10 weeks after sowing and afterward remained weedy till harvest or kept weedy for the same periods and then remained weed- free till harvest. Weed free and weedy treatments, till harvest, were included as controls. Combined analysis of both seasons indicated that unrestricted weed growth significantly reduced common bean grain yield by 57.98% compared to the weed free treatment. Yield decreased as the duration of the weed infestation increased. Plant height was significantly reduced by 45.95% under full season weedy conditions. The same trend was observed for number of leaves/plant, shoot fresh weight/plant and shoot dry weight/plant. The critical period of weed competition was found to be between 4-6 weeks after planting.