INFLUENCE OF SOWING DATE AND WEED CONTROL METHOD ON THE GROWTH AND YIELD OF SOYBEAN

Abstract

A field experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka during December, 2012 to June, 2013 with a view to find out the influence of sowing date and weed control method on the growth and yield of soybean cv. BARI Soybean-6. The experiment was consisted of four sowing dates viz. 18 December (S1), 2 January (S2), 17 January (S3), 1 February (S4); and four weed management treatments i.e. no weeding (control), hand weeding at 20 and 40 DAS (W1), hand hoe weeding at 20 and 40 DAS (W2) and chemical control by Whip Super 9 EC (Fenoxaprop-P-ethyl) @ 615 ml ha-1 at 20 DAS (W3) as post-emergence herbicide in the sub plot. The trial was set up in split plot design. The different sowing date and weed control methods showed significant effect on plant height, number of branches plant-1, dry weight plant-1, number of plants m-2, number of pods plant-1, pod length, number of seeds pod-1, 1000-seed weight, seed yield, stover yield, biological yield and harvest index of soybean. Among the infested weed species in the experimental field the dominant weeds were Lindernia procumbens (44.78 %), Echinochloa colonum (25.44 %) and Vicia sativa (20.59 %). Results revealed that early sowing (2 January) gave the highest seed yield (2.17 t ha-1). Two times hand weeding controlled the weeds most effectively which produced the highest seed yield (2.23 t ha-1) which was statistically similar with herbicide application @ 2.19 t ha-1. Interaction effect showed that highest seed yield (2.50 t ha-1) which was obtained from 2 January sowing when the crop was weeded by hand at 20 and 40 DAS.