Abstract:
A field experiment was carried out at the Agricultural Research Farm, Rajendra Agricultural University, Pusa, Samastipur, Bihar (India), during
kharif season of 2014 to evaluate the efficiency of herbicidesand crop resistance in direct seeded rice.The factors under study comprised of 12 weed management treatments on direct seeded rice. T
1-Weedy check, T
2-Weed free (3 hand weedings at 20, 40 and 60 DAS), T
3-Pendimethalin 1 l/ha (2 DAS)
fb Bispyribac-Na 30 g/ha + Azimsulfuron 30 g/ha in tank mix (20 DAS), T
4-Pendimethalin 1 l/ha (2 DAS)
fb Bispyribac-Na 30 g/ha + Azimsulfuron 15 g/ha in tank mix (20 DAS), T
5-Pendimethalin 1 l/ha (2 DAS)
fb Bispyribac-Na 15 g/ha + Azimsulfuron 30 g/ha in tank mix (20 DAS), T
6-Pendimethalin 1 l/ha (2 DAS)
fb Bispyribac-Na 15 g/ha + Azimsulfuron 15 g/ha in tank mix (20 DAS), T
7-Pendimethalin 1 l/ha (2 DAS)
fb Pendimethalin 1 l/ha + Bispyribac-Na 30 g/ha in tank mix (20 DAS), T
8-Pendimethalin 1 l/ha (2 DAS)
fb Pendimethalin 1 l/ha + Bispyribac-Na 15 g/ha in tank mix (20 DAS), T
9-Bispyribac-Na 30 g/ha + Pyrazosulfuron 25 g/ha in tank mix (20 DAS), T
10-Bispyribac-Na 30 g/ha + Ethoxysulfuron 18.5 g/ha in tank mix (20 DAS), T
11-Pendimethalin 1 l/ha (2 DAS)
fb Bispyribac-Na 30 g/ha (20 DAS) + Hand weeding (40 DAS), T
12-Brown manuring with
Sesbenia aculeate at 35 DAS. The experiment was conducted in RBD design and was replicated thrice taking rice variety Swarna Sub-1 as a test crop with RDF- 80-40-20 kg N-P
2O
5-K
2O per ha, respectively. Other crop management practices were performed as per standard package of practices.Themajor weed species dominant in the experimental field were
Echinochloa spp. among the grasses,
Cyperus spp. among the sedge and
Caesuliaaxillaris, Ammanicabaccifera, Ecliptaalba and Phyllanthuniruri among the broad leaf weeds. Combined application of herbicides as Pendimethalin 1 l/ha (2 DAS)
fb Bispyribac-Na 30 g/ha + Azimsulfuron 30 g/ha in tank mix (20 DAS)effectively curtailed the density and dry weight of grasses, sedges and broad-leaved weeds and attained superior values of weed indices (herbicide efficiency index and crop resistance index), crop yields comparable to hand weeding thrice (20, 40 and 60 DAS). But found in weedy checkwhich attained the inferior values of weed indices due to poor weed control. Thus, among different herbicidal treatments applied on direct seeded rice, T
3-Pendimethalin 1 l/ha (2 DAS)
fb Bispyribac-Na 30 g/ha + Azimsulfuron 30 g/ha in tank mix (20 DAS) had efficiently control the complex weed flora.