Evaluation of Chemical Versus Biological Weed Control in Tomato Production in Katsina State

Weed management is a critical agronomic challenge in tomato (Solanum lycopersicum) production in North West Nigeria, where weed pressure during the early growth stages can reduce yields by up to 50 percent in poorly managed fields. Chemical herbicides are widely used in Katsina State, but their environmental and health risks have prompted interest in biological and integrated weed control alternatives. This study evaluates the efficacy of chemical weed control (metolachlor herbicide), biological control using mulching with guinea grass residues, and a combination of both, compared to manual weeding and an unweeded control, on weed density and tomato yield in Katsina. A field experiment was laid out in a randomized complete block design with five treatments and three replications. Weed density counts, weed biomass, and crop yield data were collected at two and six weeks after transplanting. Results indicate that the combined chemical and biological treatment produced the lowest weed density and the highest tomato yield, while the unweeded control had the poorest performance. The biological mulch-only treatment was competitive with manual weeding in terms of weed suppression and yield. The study recommends integrated weed management combining reduced herbicide use with organic mulching for environmentally sustainable tomato production in Katsina State. Keywords: weed control, tomato, herbicide, mulching, Katsina State