Impact of Combined Industrial Effluent on Metal Accumulation, Nitrate Reductase Activity and Yield of Two Cultivars of Vigna unguiculata (L.) Walp

摘要

Combined industrial effluent from Ikeja Central Treatment Plant, Lagos, was used to irrigate Vigna unguiculata L. Walp (cowpea), cultivars IT89KD-349 (white) and IT84E-124 (red). The effluent was alkaline (pH 9.8) and had a significantly higher concentration of Ca (11.53 mg L^-1), NO₃ (83.20 mg L^-1), SO₄ (22.73 mg L^-1), Cl (15.45 mg L^-1) and Cd (2.16 mg L^-1) than the experimental soil. Nitrate reductase activity was enhanced almost throughout the period of growth of both treated cultivars but for the peak at 35 DAP shown by control white. There was a corresponding increase in the net assimilation rate and a significant increase (p<=0.05) in the biomass of leaves and pods of treated red cowpea but only the pods of treated white cowpea. Heavy metal uptake by seeds of treated plants was negligible and this may be attributed to the high accumulation of Ca by these seeds. Undiluted combined industrial effluent has good agro potential in the cultivation of red cowpea.