Weed Management in Drilled Onion (Allium cepa L.)+Chilli (Capsicum annuum L.)+Cotton (Gossypium herbaceum L.) Relay Intercropping in Rainfed Vertisols

A field experiment was carried out during 2005 and 2006 at Belvatagi, Karnataka to work out the weed management practices in drill sown onion+chilli+cotton relay intercropping in rainfed Vertisols. Pre-emergence application of oxyfluorfen @ 0.15 kg/ha and pendimethalin @ 1.0 kg/ha reduced the weed growth significantly but oxyfluorfen was toxic to onion and chilli. Pendimethalin @ 1.0 kg/ha with two or more hand weedings resulted in higher onion bulb yield and at par with farmers’ practice (88.37 q/ha). Chilli fruit yield was significantly higher with oxadiargyl @ 0.09 kg/ha with hand weeding at 20, 40, 60 and 80 DAS (11.8 q/ha), which was at par with weed free check (12.99 q/ha) and farmers’ practice (10.09 q/ha). Seed cotton yield was found better with oxyfluorfen @ 0.15 kg/ha alongwith hand weeding at 20, 40 and 60 DAS. Application of pendimethalin @ 1.0 kg/ha with three hand weedings at 20, 40 and 60 DAS was found better for onion bulb and chilli fruit yield and comparable with farmers’ practice for the onion+chilli+cotton relay intercropping system. This resulted in higher net returns (Rs. 64,390/ha) and B: C ratio (3.99).