Atrazine, Allelopathic water extracts, Herbicide combination, Halosulfuron-methyl, Sugarcane, Weed Management

A field experiment was conducted during 2016-17 and 2017-18 at Agricultural Research Farm of Institute of Agricultural Sciences, BHU, Varanasi. The experiment was laid out in split plot design with five treatments in main plots and five treatments in sub plots. In main plots, there were five herbicide combinations, viz. pre-emergence application (PE) of atrazine 2 kg/ha at 3 days after planting (DAP) followed by (fb) post-emergence application (PoE) of halosulfuron-methyl 150 g/ha at 45 DAP, metribuzin 2 kg/ha fb halosulfuron-methyl 150 g/ha, triazinone 1.0 kg/ha fb halosulfuron-methyl 150 g/ha, weed free and weedy check. In sub-plots, five aqua based plant/allelopathic extracts were tested, viz. cow urine (500 L/ha), parthenium extract (15%), sunflower + sorghum + maize extract (15%), eucalyptus extract (15%) and water (600 L/ha). The lowest weed density and biomass, weed index (WI), NPK uptake by weeds and the highest weed control efficiency (WCE) were recorded with atrazine 2 kg/ha PE fb halosulfuron-methyl 150 g/ha PoE in combination with sorghum + sunflower + maize extract, while need based hand weeding recorded higher cane yield.