WEED MANAGEMENT IN SUNFLOWER WITH ALLELOPATHIC WATER EXTRACT AND REDUCED DOSES OF A HERBICIDE

Field studies were undertaken at the Agronomic ResearchArea, Faculty of Agriculture, Gomal University, Dera Ismail Khan,Pakistan, during 2006-07, to investigate the effectiveness of allellochemicalsof sorghum and sunflower water extracts. The experimentwas laid out in Randomized Complete Block Design with fourreplications. The approved sunflower variety ‘Pioneer 64 – A93, in plotsize of 4×2.8 m2 was planted on 10th March 2007. The experimentcomprised of six treatments and a weedy check (control). Thetreatments were Sorgaab (sorghum water extract)+ Sunflower waterextract each at 18 L ha-1 (early Post-emergence), Sorgaab+ Sunflowerwater extract each at 15 L ha-1 (early pre-emergence), pendimethalinat 825 ml ha-1 full dose (pre-emergence), pendimethalin @ 413g ha-1half dose (pre-emergence), Sorgaab + Sunflower water extract eachat 18 L ha-1 + pendimethalin @ 413ml ha-1 (half dose) (preemergence)and Sorgaab + Sunflower water extract each at 15 L ha-1+ pendimethalin @ 13 ml ha-1 (half dose) as pre-emergence. Datawere recorded on weed density, fresh and dry weed biomass, numberof plants m-2, achene yield (kg ha-1), biological yield (kg ha-1) andharvest index (%). The lowest weed density AND consequently thehighest biological yield (7443 kg ha-1) was observed in plots receivingfull dose of pendimethalin @ 825 g ha-1. It was followed by plot usingfull dose of Sorgaab + sunflower + pendimethalin, where the biologicalyield was 7235 kg ha-1. Minimum yield (6025 kg ha-1) was recorded inthe weedy check plots. Sorghum and sunflower water extracts arevery useful in allelopathic control of weeds in different crops. Thisweed control strategy is environment friendly and also reduces thecost of production.