Bispyribac-sodium + metamifop

Broad-leaved weeds

Direct-seeded rice

Grasses

Penoxsulam + cyhalofop-butyl

Sedges

Weed seed bank

To study the effect of post-emergence applied herbicide mixtures, viz. bispyribac-sodium + metamifop and penoxsulam  + cyhalofop-butyl on soil weed seed bank, weed seed bank assay were carried out at College of Agriculture Vellayani, Thiruvananthapuram during rainy season 2014 and winter season 2014-15. Weed seed bank assay results revealed a significant reduction in the emergence of sedges, broad-leaved weeds (BLW) and grasses from the soil treated with herbicide mixtures compared to individual application of bispyribac-sodium at 25 g/ha and penoxsulam at 22.5 g/ha. The results also revealed that penoxsulam + cyhalofop-butyl was more effective in reducing the weed seed bank than bispyribac sodium + metamifop. The higher doses of penoxsulam + cyhalofop-butyl (135, 130 and 125 g/ha) were found to be more effective than its lower dose of 120 g/ha.  Among the tested doses of bipyribac-sodium + metamifop, its higher doses (90 and 80 g/ha) performed better than lower doses (60 and 70 g/ha) in reducing the soil weed seed bank. Hence, post-emergence application of penoxsulam + cyhalofop-butyl either at 125 or 130 or 135 g/ha or bispyribac-sodium + metamifop at 80 or 90 g/ha at 15 DAS (days after sowing) can be recommended for the effective management of weed seed bank in wet direct-seeded rice.