Effect of herbicides on distribution and interference of weeds, growth and yield of wheat (Triticum aestivum) in Kandahar, Afghanistan

Abstract

Weeds are the major constraint to achieving higher wheat yield in Afghanistan. To evaluate weed interference and its impact on wheat, a field experiment was undertaken during winter season in 2014–15 at Afghanistan National Agricultural Science and Technology University (ANASTU), Kandahar. Seven weed control treatments comprising isoproturon 0.75 and 1.0 kg/ha at 35 days after sowing (DAS), sulfosulfuron 20 and 25 g/ha at 35 DAS, isoproturon + 2,4-D 0.75 + 0.5 kg/ha at 35 DAS (tank-mix), weed-free check and weedy check were laid out in a randomized complete block design with three replications. Results showed that grassy weeds constituted 62.7% of the total weeds and were mostly dominant. All herbicides/weed control treatments influenced weed interference, wheat cropgrowth and yield significantly. Sulfosulfuron 25 g/ha at 35 DAS resulted in significant reduction in weed density by 95.2% (i.e. weed control efficiency) and dry weight by 95.1% (i.e. weed control index), respectively. This treatment led to significant improvements in wheat growth (Leaf area index, dry matter accumulation) and grain (4.6 t/ha) and biological yields (10.6 t/ha), and was superior to other herbicide treatments. It increased wheat grain and biological yields by 24.3% and 17.8%, respectively, compared to weedy check. Therefore, the application of sulfosulfuron 25 g/ha at 35 DAS may be recommended for better weed control and higher wheat yield in Kandahar, Afghanistan, and in similar agro-ecologies of the tropics and sub-tropics.