Effect of Pre and Post Emergence Herbicides for Nitrogen Uptake and Economics in Chilli (Capsicum annuum L.) + Onion (Allium cepa L.) + Cotton (Gossypium herbaceum L.) Intercropping System

The field experiment was carried out in medium deep black soil in farmer's field of Mugali, Ron taluka in Gadag during kharif 2011 under rainfed condition to find out sequential application of pre and post emergence herbicides for weed management in chilli + onion + cotton intercropping system. The experiment was laid out in a randomized block design with three replications. The experiment consisted of 7 treatments involving four pre emergence herbicides viz., pendimethalin @ 1.0 kg a.i per ha, butachlor @ 1.0 kg a.i per ha, oxadiargyl @ 90 g a.i per ha and alachlor @ 1.0 kg a.i per ha and one post emergence herbicide oxyfluorfen 0.15 kg a.i per ha and compared with farmers’ practice (3 HW at 20 days interval), weed free and weedy check. Application of pendimethalin @ 1 kg per ha fb oxyfluorfen @ 0.15 kg per ha recorded lower number of weeds and total weed dry weight results in higher nitrogen uptake by chilli, onion and cotton (53.6, 77.0 and 37.5 kg/ha, respectively) and lower nitrogen uptake by weeds (29.3kg/ha). Higher gross return, net return and B: C ratio was recorder in pendimethalin @ 1 kg per ha fb oxyfluorfen @ 0.15 kg per ha (Rs.146752/ha, Rs.110114/ha and 4.01, respectively) compared to farmers’ practice (Rs.122543/ha, Rs.88127/ha and 3.56, respectively).