Tank mixing of allelopathic crop water extracts with pendimethalin helps in the management of weeds in canola (Brassica napus) field

A field experiment was conducted to investigate the allelopathic effects of sorghum, sunflower, brassica and rice combined with low rates of pendimethalin for weed management in canola (Brassica napus L.) field. Crop water extracts at 15 L ha^-1 each in combination with pendimethalin at 400 and 600 g active ingredient (a.i.) ha^-1 were sprayed immediately after sowing. Full dose of pendimethalin 1200 g a.i ha^-1 was used as standard. A weedy check was also maintained for comparison. Sorghum and rice water extracts each at 15 L ha^-1 combined with 600 g a.i. ha^-1 showed maximum (67.58 & 66.21%) reduction in total weed density at 40 and 60 days after sowing (DAS), respectively. All the treatments offered more than 80% reduction in total weed dry weight over control at 40 DAS, while 44.93 to 63.99% reduction in total weed dry weight over control at 60 DAS was recorded in all the treatments. The plots treated with sorghum and sunflower water extracts each at 15 L ha^-1 combined with 600 g a.i. ha^-1 pendimethalin recorded maximum seed yield (2.604 Mg ha^-1), which was 39.99% greater as compared to control. Herbicide dose may be reduced by 50-67% in combination with allelopathic water extracts for effective weed control and higher yields in canola field.