EFFECT OF DIFFERENT METHODS OF WEED CONTROL ON WEED GROWTH AND YIELD OF COTTON ( Gossypium hirsutum L. )

Abstract

Weed control study on cotton conducted during summer growing season 2005 at Sumel and Zakho (Dohuk Governorate) in Iraqi Kurdistan region, to determine the effect of different methods of weed control. Cultural practices used in different row spacing (60 or 80 cm) while mechanical methods used hoeing at 4, 8, 4+8 weeks after sowing (WAS). Also chemical herbicides such as Treflan pre-planting soil incorporated, Gallant super early post-emergence and Treflan+Gallant were used. Weeds can compete strongly with cotton, potentially reducing cotton yields .Decrease in row spacing (60 cm) was much better for reducing weed dry weight than 80cm within 75 or 100 days after sowing. On the other hand, the narrow spacing gave more cotton yield and increase up to 76.88 %, 40.81% at Sumel and Zakho locations respectively. Hoeing at an early stage or two times of hoeing was a good option for weed control. Also two times of hoeing 4+8 (WAS) was more effective on weed than row spacing. Lint yield was higher up to 408.75%, 173.55% in two times of hoeing treatment at the two locations, respectively. Treflan or Treflan+Gallant gave significant result in reducing weed biomass in both locations over two periods. However, Treflan+Gallant reduced weeds dry weights 42.8%, 41.8%, 70.6% and 71.5% at the two locations within the two periods, respectively.