Direct-seeded rice, Herbicides efficacy, Rice-wheat cropping system, Spray technology

The spraying herbicides with unrecommended spray technology using gun sprayers/knapsack sprayers equipped with single hollow-cone or flat-fan nozzle and lower water volume, has been one of the important factors responsible for the lower efficacy of herbicides in rice-wheat cropping system in Punjab, India. The improved spray technology, involving spraying with tractor operated multi-boom sprayer fitted with flat-fan nozzles, was compared with farmer’s practice in rice-wheat system adopting farmers’ field in Amritsar County during 2015-16 and 2016-17. In dry-seeded rice, pre-emergence application (PE) of pendimethalin alone and its tank-mix with pyrazosulfuron were used, and in wheat, pendimethalin alone and pre-mix of sulfosulfuron plus metsulfuron-methyl were used for weed management. The major weed flora in dry-seeded rice included: Dactyloctenium aegyptium, Echinochloa colona, Echinochloa crus-galli, Leptochloa chinensis and Digitaria ciliaris and in wheat, Phalaris minor was the dominant weed. The improved spray technology enhanced weed control by 93% in dry-seeded rice and by 95 % in wheat, compared to farmer’s practice. The study indicated good scope for enhancing herbicides efficacy by the use of appropriate recommended spray technology