J. N. K. V. V. Zonal Agricultural Research Station, Powarkheda, Hoshangabad-461 110 (M. P.), India.
Echinochloa crusgalli, Dinebra arabica, Rottboellia exaltata, Digitaria sanguinalis, Cyperus rotundus, Commelina benghalensis and Euphorbia geniculata constituted major part of the weed flora. Chlorimuron gave an efficient control of sedge and all broad-leaved weeds. The grasses except Rottboellia sp. proved to be tolerant to this herbicide. The seed yields of soybean under all the treatments were significantly higher than weedy control (657 kg/ha). Early application of chlorimuron proved superior but its doses could not have significant effect. Seed yield with two hand weedings was maximum (1828 kg/ha). Amongst herbicide treatments, application of chlorimuron at 3 DAS @ 6.0, 9.0 and 12.0 g/ha with the yield of 1259, 1284 and 1379 kg/ha proved superior to subsequent timings and the pendimethalin 1.0 kg/ha. Incremental net returns were maximum with two hand weedings (Rs. 7289/ha) followed by chlorimuron 12.0 g/ha (Rs. 4808/ha), 6.0 g/ha (Rs. 4448/ha) and 9.0 g/ha (Rs. 4313/ha), while the incremental benefit: cost ratio was the highest with chlorimuron 6.0 g/ha at 3 DAS (4.59).
