Effect of post-emergence herbicides at variable soil moisture on weeds and yield of wheat

An experiment was carried out during winter seasons of 2008–09 and 2009–10 at JNKVV, Jabalpur to study the response of post-emergence herbicides at variable available soil moisture (ASM) on weed biomass, yield attributing characters and yield of irrigated wheat. The weed control efficiency was higher at 100% ASM at the time of herbicides application and it was declined with every five per cent decrease in available soil moisture and was minimum under 80% ASM. The application of clodinafop fb 2,4-D registered significantly higher weed control efficiency over isoproturon and clodinafop alone. Yield attributes, viz. number of effective tillers, length of ear head, weight of ear head, weight of grains per ear head, number of grains per ear head, test weight and grain and straw yields were significantly higher at 100% ASM were at par with 95 and 90% ASM. Clodinafop fb 2,4-D proved significantly superior and produced 4.9, 5.8 and 18.4% higher grain yield over isoproturon, clodinafop and weedy check, respectively.