Influence of S-Metolachlor and Nicosulfuron on Weed Flora, Density, and Yield Performance of Maize

Abstract

Maize production in areas with heavy weed infestation depends largely on effective weed control. Therefore, field trials were conducted during 2021 and 2022 wet seasons at the Irewumi community in Ilorin West Local Government Area of Kwara State to examine the effects of Smetolachlor and nicosulfuron on weed population characteristics and maize performance. The study evaluated changes in weed species composition, weed density, weed suppression efficiency, and growth and yield parameters of maize. The experiment followed a randomized complete block design consisting of six treatment options replicated four times. These treatments included a weed-free plot, two application rates of S-metolachlor (3 and 6 L ha⁻¹), two rates of nicosulfuron (1.5 and 3 L ha⁻¹), and an untreated weedy control. Observations and measurements were taken on weed flora, weed density, weed control efficiency, and maize yield components. Findings revealed that plots treated with herbicides showed markedly lower weed density and improved weed control efficiency compared to the untreated plots. Among all treatments, nicosulfuron applied at 1.5 L ha⁻¹ produced the most effective weed suppression, followed closely by S-metolachlor at 3 L ha⁻¹. These treatments also resulted in superior maize yield performance. Based on the outcomes of the study, it was concluded that applying nicosulfuron at 1.5 L ha⁻¹ or S-metolachlor at 3 L ha⁻¹ provides effective weed control and enhances maize grain yield under the environmental conditions of the study area. The use of these herbicide rates is therefore recommended for maize production in similar agro-ecological zones.