Effect of Post-emergence Herbicides for Weed Management in Soybean (Glycine max)

Dominant weeds of the experimental field were carpetweed (Trianthema portulacastrum L.) and barnyard grass (Echinochloa colona L.) among broadleaf and grass weeds, respectively. Four herbicides i. e. fomesafen, haloxyfopmethyl, chlorimuron and prometryn were evaluated alone and in combination against weeds in soybean during khar if seasons of 2000 and 2001 at CCS Haryana Agricultural University, Hisar, India. Fomesafen effectively controlled carpetweed, cock's comb and kondra but none of the grass weeds. On. the other hand, haloxyfopmethyl provided excellent control of grass weeds (barnyard grass). Chlorimuron and prometryn, application alone though provided good control of both non-grassy and grass weeds when compared to unweeded control but poor than other herbicide treatments. Combination of fomesafen and haloxyfopmethyl, and chlorimuron and haloxyfop provided 85 to 95% control of non-grassy weeds and 70–90% of grass weeds. Tank mixture of fomesafen and haloxyfop at 200+150 g or 250+150 g ha⁻¹ and chlorimuron+haloxyfop at 6+150 g or 9+150 g ha⁻¹ produced pods per plant and grain yield of soybean similar to season long weed-free yields. Among herbicides, alone application of chlorimuron at 9 or 12 g ha⁻¹ provided satisfactory crop yields.