Interaction between Nicosulfuron dose and timing on Johnson grass and maize competition indices

Chemical weed control is a main component of management programs of crop productions. Timely herbicide application significantly increases herbicide efficiency. A field experiment was conducted to study the effect of Nicosulfuron timing and dose on S. halepense competition with maize. Experiment was split-plot in three replications. Main plots were herbicide dose of 0, 1, 1.5, 2, 2.5 kg/ha and sub plots were herbicide timings of 2-4 l, 4-6 l, 6-8 l of maize growth. Growth parameters of maize including height, leaf area (LA) and total biomass (TB) were measured. Results showed, the highest height, LA and TB were obtained from Nicosulfuron application at 1.5 Kg/ha in 2-4 l of maize and no significant difference was shown to herbicide recommended dose or higher. With delay in herbicide application, the height and TB of S. halepense increased and its competition with maize got raised. It caused decrease in maize growth indices. Current study showed main effect of herbicide dose in changing weed-crop interactions. Successful management would change competition in advantage to crops using lower herbicide doses to achieve both economic and environmental purposes in sustainable crop protection.