Weed Flora Dynamics, Control Strategies and Varietal Response of Soybean (Glycine max L.) Productivity in the Sudan Savanna of Nigeria

Abstract

A field study was conducted during the 2022 rainy season at Bayero University Kano and Bunkure, in Nigeria’s Sudan savanna, to evaluate weed flora dynamics, control treatments, and varietal performance on soybean. The experiment employed a split-plot design with seven weed control treatments comprising of pendimethalin at 1.0 and 1.5 kg a.i. ha⁻¹, imazethapyr at 100 g a.i. ha⁻¹, pendimethalin at 1.0 kg a.i. ha⁻¹ + imazethapyr at 100 g a.i. ha⁻¹, pendimethalin at 1.0 kg a.i. ha⁻¹ +  hoe weeding at 6 weeks after sowing (WAS), hoe weeding at 3 and 6 WAS, and weedy check as main plots, and three soybean varieties (TGX-1448-2E, TGX-1835-10E, and TGX-1951-3F) as subplots. Results identified nineteen weed species, with broadleaf weeds like Ipomoea spp. and Cirsium vulgare predominating, while sedges such as Cyperus rotundus were more prevalent at Bunkure. Hoe weeding at 3 and 6 WAS and the integrated application of pendimethalin at 1.0 kg a.i. ha⁻¹ + imazethapyr at 100 g a.i. ha⁻¹ achieved the highest weed control indices (>70%) and lowest weed biomass. These treatments significantly enhanced leaf area index, pod weight, and seed yield (>2.6 t ha⁻¹), compared to the weedy check (<1.0 t ha⁻¹). Among varieties, TGX-1951-3F exhibited superior canopy development, weed competitiveness, and yield potential. Integrating herbicide use, specifically pendimethalin at 1.0 kg a.i. ha⁻¹ + imazethapyr at 100 g a.i. ha⁻¹, offers an efficient, less labor-intensive alternative to manual hoeing. Consequently, this integrated approach is recommended for sustainable and economically viable soybean production in the Sudan savanna.