Comparative evaluation of weed control methods on cowpea (Vigna unguiculata (L.) Walp) production in the savanna Agro-ecological zone of Nigeria

Weed competition has the capability of lowering the quality of vegetative growth as well as the quality and seed yield. A study was conducted during the 2014 and 2015 cropping seasons at the Research farm of the National Centre for Agricultural Mechanization, Ilorin, to compare some weed control methods in cowpea production in the savanna agro-ecological zone of Nigeria. Five weed control methods, Rotary cultivator at 3WAP + Hand weeding at 6 WAP, Hand weeding at 3 and 6 WAP, Pre-emergence herbicide + Hand weeding at 6 WAP, Post-emergence herbicide at 3 WAP + Hand Weeding at 6 WAP and no weeding Control were evaluated. The experiment was laid out in randomized complete block design with three replications.The results were subjected to analysis of variance and treatment means were separated using the Least Significant Difference method. The results of this study revealed that, the effect of different weed control methods employed significantly affected the performance of cowpea. The presence of weeds in the no weeding control significantly reduced both the plant height, number of branches crop vigour, total plant biomass and grain yield. Results also show that, pre- emergence + hoe weeding at 6 WAP significantly reduced weed cover score, increased plant height and number of branches which culminated into increased number of pods per and grain yield. Hence pre- emergence herbicide + hoe weeding at 6 WAP was more effective in controlling weeds in cowpea production in the study area and can therefore be recommended to cowpea farmers in the Savanna Agro-Ecological zone of Nigeria