INFLUENCE OF WEED CONTROL METHODS ON THE GROWTH AND YIELD OF SOYBEAN VARIETIES

Abstract

The experiment was conducted at the farm of Sher-e-Bangla Agricultural University, Sher-e-Bangla Nagar, Dhaka, Bangladesh during the period from December 2013 to April 2014 to study the influence of weed control methods on the growth and yield of soybean. The experiment comprised of two factors- Factor A: Soybean variety (3 varieties): Sohag (V1), BARI soybean 6 (V2) and BINA soybean 1 (V3); Factor B: Weed control methods (4 levels): No weeding (W0), Hand weeding at 20 and 40 DAS (W1), Chemical control by whip super 9EC herbicide application at 20 DAS (W2) and Bioherbicide-Siam weed extract (W3). The experiment was laid out in Split plot Design with three replications. Results of the experiment showed that at 30, 45, 60 and 75 DAS, the maximum number of weed population (25.00, 31.22, 25.22 and 20.44, respectively) was observed in W0 while the minimum number (11.78, 14.67, 14.44 and 14.11, respectively) in W2. In case of variety, at 30, 45, 60, 75 DAS and at harvest, the tallest plant (17.90, 34.35, 54.09, 58.63 and 65.39 cm, respectively) was found from V2, while the shortest plant (16.46, 29.26, 46.41, 52.81 and 56.12 cm, respectively) was observed from V1.The highest seed yield (1.99 t ha-1) was recorded in V2 while the lowest seed yield (1.52 t ha-1) was observed in V1. For weed control methods, at 30, 45, 60, and 75 DAS and at harvest, the tallest plant (18.56, 35.51, 56.80, 61.99 and 68.17 cm, respectively) was observed in W2, whereas the shortest plant (15.04, 25.95, 38.70, 45.30 and 52.46 cm, respectively) from W0. The highest seed yield (2.01 t bha-1) was observed in W2, whereas the lowest seed yield (1.41 t ha-1) from W0. Interaction effect of varieties and weed control methods showed that at 30, 45, 60, and 75 DAS and at harvest, the tallest plant (19.86, 38.65, 61.66, 66.45 and 73.10 cm, respectively) was found in V2W2 while the shortest plant (14.51, 24.55, 36.58, 44.06 and 46.69 cm, respectively) from V1W0. The highest seed yield (2.23 t ha-1) was recorded in V2W2 while the lowest seed yield (1.26t ha-1) from V1W0.