INFLUENCE OF VARIED DENSITIES OF AKIDI [Vigna unguiculata (L.) Walp.] INTERPLANT ON WEED CONTROL IN MAIZE (Zea mays L.) FIELD IN ISHIAGU SOUTHEASTERN NIGERIA

Abstract

This study was conducted to determine biocontrol ability of Akidi interplanted at different densities to check weed population in maize field at Ishiagu, Nigeria. There were six treatments, namely: maize interplant with Akidi [Vigna unguiculata (L.) Walp.: Fabaceae] at 20,000 (T₁), 30,000 (T₂), 40,000 (T₃) plants ha^-1, sole maize+hoe weeding (T₄), sole maize weedy check (T₅), and sole maize+Primextra 2.5 Lha^-1 (T₆); arranged in Randomized Complete Block Design (r=4). Weed species identification, Relative Importance Value (RIV%), weed biomass (g) and Maize biomass (g) were determined at sixty Days After Sowing (DAS). Data were analysed using descriptive statistic and ANOVA at α_0.05. Results showed that there were seventeen different weeds identified in the maize plots belonging to nine botanical families. The treatment plots, however, were dominated by species of Asteraceae (4), Poaceae (4) and Cyperaceae (2) families. The weed population dynamics showed that Cyperus esculentus had highest RIV (16.00) across all the maize plots followed by Corchorus olitorius, which had RIV of 14.00. Maize-Akidi interplant at 40,000 plants ha^-1 (T₃) gave remarkably the highest maize biomass accumulation (96.50 g) which was significantly higher than the maize-akidi bean interplant 20,000 (T₁) which had 63.50 g at 60 DAS. Also, T₃ gave the least weed species biomass accumulation (14.5 g) which was significantly less than the other maize-akidi interplants (T₁ and T₂) that had 32.00 and 29.00 g, respectively at 60 DAS. Maize-Akidi interplant at 40,000 plants ha^-1 suppressed the growth of weeds by taking up spaces and utilizing available growth resources, and enhanced maize crop growth and yield.