SCREENING OF SOME ARABLE CROP PLANTS FOR TOLERANCE TO CASSAVA EFFLUENT USED FOR WEED CONTROL
The advocacy for allelopathic weed control has justified that phytotoxicity of allelochemicals on crops be investigated since crop injury is an associated challenge of chemical weed control. A laboratory experiment was conducted to evaluate the effect of cassava effluent (CE) concentrations on germination of kenaf (Hibiscus cannabinus L.), cowpea (Vigna unguiculata (L) Walp.), okra (Abelmoschus esculentus (L.) Moench), maize (Zea mays L.), rice (Oryza sativa L.) and tomato (Lycopersicon esculentum Mill.). The experiment comprised four CE concentrations (120, 240, 360 and 480 g CN ha-1) and a control (no CE) as treatments. These were laid out in a completely randomized design with three replicates. A follow-up screen-house experiment was conducted to investigate the effect of CE on growth and yield of okra using the same experimental treatments. The results showed that germination percentage decreased with increasing CE concentration in all the crops tested. Kenaf seed had germination inhibition percentage as high as 73% in the least CE concentration whereas okra seed had the least germination inhibition in CE concentrations that impacted most on other crops. CE did not significantly reduce the number and weight of okra pods compared to control treatment. Hence, it is recommended that the selective use of CE for weed control is feasible in okra since its yield was not reduced.