DETERMINING CRITICAL WEED COMPETITION PERIOD IN MAIZE (zea mays L.) SOWN UNDER DIFFERENT TILLAGE INTENSITIES

A field experiment was conducted at the Agronomic Research Area, Department of Agronomy, University of Agriculture, Faisalabad to determine the critical weed competition period in maize (Zea mays L.) sown under different tillage intensities. The field trial was laid out with split plot design having three replicates with a net plot size of 4.5 m x 6 m. The experiment comprised of three tillage practices namely deep cultivation with disc plough + 3 cultivations with cultivator, rotavator + 3 cultivations with cultivator, and only 3 cultivations with cultivator; and five weed competition periods of 20, 30, 40 days after crop emergence along with weed free and weedy check. The linear increase in the density of weeds (m^-2) with the competition periods would be due to more time period available for weed seed germination which ultimately resulted in the reduction of total grain yield. Plant population at harvest, number of grains cob^-1, number of grain rows cob^-1, total number of grains cob^-1, 1000-grain weight (g), grain yield, dried stalk yield and biological yield were maximum in disc plough + 3 cultivations with cultivator.