Integrated Weed Managementin Onion (Allium cepa L.)

Field experiment was carried out for two consecutive years during summer seasons of 1998 and 1999 to find out the appropriate and economic weed management practice in onion variety N 53. Pre-emergence application of pendimethalin, metolachlor and oxyfluorfen at 1.0, 0.75 and 0.15 kg ha⁻¹, respectively, and each supplemented with one hand weeding at 35 days after transplanting (DAT) was found significantly superior over application of these herbicides at higher rate in reducing dry matter of weeds and enhancing bulb yield of onion. Pre-emergence application of oxyfluorfen at 0.15 kg ha⁻¹ supplemented with one hand weeding at 35 DAT was found equally effective to that of hand weeding twice at 20 and 35 DAT in alleviating weed competition and increasing bulb yield. There was reduction in bulb yield to the extent of 78.63% due to weed competition under weedy check. On the contrary, increase in bulb yield in the range of 159.36 to 447.25% was observed due to adoption of weed management practices. Though hand weeding twice gave maximum additional return of Rs. 95760 ha⁻¹ over weedy check, the maximum weed control efficiency (92.2%), net additional return (Rs. 91070 ha⁻¹) over control and B: C ratio (56.6) were obtained under pre-emergence application of oxyfluorfen at 0.15 kg ha⁻¹ supplemented with one hand weeding at 35 DAT.