Allelopathic Effect different Intercropping System and Tree Leaf Extract Spray on Weed Density, Dry Matter and Weed Control Efficiency in Irrigated Cotton

A field experiment was conducted at Agricultural College and Research Institute, Madurai to study the combined effect of intercropping and weed management practices on weed control in irrigated cotton during the year of 2016. Cotton + sorghum intercropping system registered significantly lower weed density and dry matter production at all the stages crop growth, while sole cotton recorded the higher weed density and dry matter production. In weed management practices, significantly lesser weed density and dry matter were recorded under pre-emergence application of pendimethalin @ 1.0 kg a.i. ha-1 during 20 DAS. At 40 and 60 DAS hand weeding twice at 20 and 40 DAS recorded lower weed density and dry matter. Among the interaction effect, cotton + sorghum and application of pendimethalin 1.0 kg a.i. decreased the weed populations and dry matter at 20 DAS. At 40 and 60 DAS intercropping of cotton with sorghum and hand weeding twice at 20 and 40 DAS significantly registered lesser weed density and dry matter. The maximum weed density and dry matter was noticed under sole cotton with control. The higher weed control efficiency (WCE) of 81.2% was obtained under the treatment of pre-emergence application of pendimethalin @ 1.0 kg a.i. ha-1 at 20 DAS. At 40 and 60 DAS (86.3 and 94.4%) WCE was higher with hand weeding twice at 20 and 40 DAS.