WEED MANAGEMENT IN WHEAT AS AFFECTED BY TILLAGE AND HERBICIDES

To evaluate the impact of various tillage systems incombination with herbicides on weed density and grainyield of wheat under rice-wheat cropping system, anexperiment was conducted in low precipitation zone ofNWFP (Dera Ismail Khan), Pakistan during 2007–2009. Theexperiment was laid out in randomized complete blockdesign with split plot arrangements replicated four times.The treatments comprised of 3 tillage systems, includingconventional tillage with disk ploughing (CT), reducedtillage with shallow ploughing through rotavator (RT), andzero tillage with stubble direct drilling (ZT) as main plotswhile five weed control treatments viz. 2,4-D ester @ 1.25L ha-1, Puma super 75 EW @1.25 L ha-1, 2,4-D + Pumasuper @1.25 L ha-1 each, Affinity 50 WDG @ 2 kg ha-1 andweedy check as subplots. Herbicides had significant effecton weed density, dry weed biomass (DWB), and grainyield. Tillage x herbicides interaction occurred for weeddensity and grain yield only. Maximum grain yield (6906.9kg ha-1) was recorded with Affinity. Maximum weed densitym-2 (75.5) and DWB (220.4 g m-2) were recorded in weedycheck, while maximum grain yield (5583.8 kg ha-1) wasobtained from RT being statistically similar to grain yield(5575.1 kg ha-1) in ZT. The lower grain yield (5479.3 kgha-1) in CT was due to maximum weed density m-2 (48.3),and DWB (136.5 g m-2). Affinity was the most effectiveherbicide against grasses as well as broad-leaved weeds incombination with either ZT or RT and resulted in highergrain yield.