Study of the Effect of Herbicide Application on Weed Control and Maize Yield in Plateau State

Chemical weed control with pre- and post-emergence herbicides offers time and labour savings for maize farmers in North Central Nigeria, and evaluating the efficacy of commonly available herbicide formulations relative to hand weeding is important for evidence-based extension recommendation in Plateau State. This study investigated the weed control efficacy and maize yield effects of three herbicide treatments (atrazine as pre-emergence, nicosulfuron as post-emergence, and atrazine followed by nicosulfuron) compared with two hand weedings and a weedy control at Mangu LGA, Plateau State. A randomised complete block design with six treatments and three replications was conducted during the 2023 rainy season using SAMMAZ 29 variety. Weed density and dry weight at 4 and 8 weeks after application, and maize grain yield were measured. Results showed that the atrazine plus nicosulfuron sequential treatment achieved the best weed control (83.7 percent reduction in weed dry weight at 8 WAP) and grain yield (4.41 tonnes per hectare), comparable to two hand weedings (4.38 t ha-1) and significantly better than the weedy control (1.97 t ha-1). Pre-emergence atrazine alone was effective against broadleaved weeds but inadequate for late-emerging grasses. Cost-benefit analysis showed the sequential herbicide treatment had the best net return. The study recommends the sequential atrazine plus nicosulfuron treatment as a cost-effective weed management option for maize farmers in Plateau State.

Keywords: herbicide application, weed control, maize yield, Plateau State, North Central Nigeria