INTEGRATED IMPACT OF TILLAGE AND HERBICIDES ON WEED CONTROL AND WHEAT YIELD IN COTTON BASED CROPPING SYSTEM

Field experiment was conducted at Agricultural Research Institute, Ratta Kulachi, Dera Ismail Khan, Pakistan, during Rabi 2010-11 to study the effect of tillage and herbicides on weed control and wheat yield in cotton based cropping system. The experiment was laid out in a randomized complete block design with split plot arrangement replicated four times. The treatments included in the experiment were three tillage systems viz. zero tillage (no tillage), reduced tillage (with cultivator followed by rotavator), and conventional tillage (with disk plough, cultivator and rotavator) which were assigned to the main plots; while five weed control treatments included- post emergence herbicides i.e., Buctril super 60 EC (Bromoxynil + MCPA) @ 0.45 kg, Topik 15 WP (Clodinafop-propargyl) @ 0.09 kg, Buctril super 60 EC @ 0.45 kg + Topik 15 WP @ 0.09 kg a.i. ha^-1, a hand weeding (at 30 days after sowing), and a weedy check (control) were assigned to the subplots. Data were recorded on weed density m^-2, spikes m^-2, grains spike^-1, 1000-grain weight (g), grain yield (kg ha^-1), cost of production (Rs. ha^-1) and net benefit (Rs. ha^-1). Tillage and herbicides significantly affected the weed density, wheat yield and other yield components. Conventional tillage had lower weed density (18 plants m^-2), higher number of spikes m^-2(367), higher grain yield (5902 kg ha^-1) and net benefit of Rs.99459 ha^-1 as compared to other tillage systems. Buctril super 60 EC + Topik 15 WP significantly reduced weed density and performed better in getting higher wheat yield and net economic return compared to other weed control treatments. In conclusion conventional tillage in combination with Buctril super 60 EC @ 0.45 kg + Topik 15 WP @ 0.09 kg a.i. ha^-1 is recommended for effective weed management, enhanced grain yield and higher net benefit in wheat crop.