Effect of Selected Pre-Emergence Herbicide, Nicosulfuron and Humic Acid on the Performance of Maize

Weed infestation remains a major constraint to maize (Zea mays L.) production in Nigeria, leading to significant yield losses. This study investigated the effect of selected pre- and post-emergence herbicides and humic acid on weed control and the performance of maize. The experiment was carried out at the University of Ilorin Teaching and Research Farm during the 2024 growing season. The experiment was designed as a Randomized Complete Block Design (RCBD) with three replications. The treatments were the pre-emergence application of Traceforce (Prometryn 150g/L + Acetochlor 250g/L EC) and post emergence application of Guardforce (Nicosulfuron 4g/L, 75% WDG) at 4 weeks after planting, alongside either biostimulants Blackforce (Potassium humate 97% WG) or POW Humus (Humic acid 85% WSG), hand-weeding at 3 and 6 weeks after planting, and weed-free with the application of NPK at 3 WAP at the rate of 300-400kg per ha, and Urea(46% N) at the rate of 100-150kg per ha, at 6 WAP on the weed free plot. The field was ploughed, harrowed, and ridged. The plot size was 5 ridges of 5m long. maize seeds were sown at 25cm x 75cm plant spacing, and Emamectin benzoate 5% WDG was applied to control armyworms. Data were collected on weed density and weed biomass (using discrete and continuous quadrats) as well as maize yield and yield components. Five weed species were prevalent on the field (Mitracarpous villous, Hyptis suaveolens, Eleusine indica, Gomphrena celosioides and Urochloa trichopus). Herbicide-treated plots significantly reduced weed density by 85.04 to 85.18%. Plots treated with Traceforce + Guardforce + POW Humus had 85.18% weed control and the highest grain yield of 4.20t/ha. It is recommended that further trials be conducted across different agro-ecological zones to validate these findings.