Effect of Escravos Light Crude Oil on Cowpea (Vigna unguiculata) Germination and Growth

This study was carried out to investigate the effect of Escravos light crude oil on cowpea germination and growth. Two varieties (white and brown) of cowpea (Vigna unguiculata) seeds were used and studies on the effect of cowpea nodulation were investigated on soils treated with various concentration of Escravos light crude oil. The oil was mixed with the soil, watered to keep it moist and left for 3 days for percolation of the oil. Control was set up with uncontaminated soil and each experiment was set in duplicates and watered every morning with 10mls of water. The plants were observed for the rate of growth, shoot length, leaf colour, width of foliage and root nodulation. After 42 days of planting, the plant was harvested; roots were carefully removed and examined for nodulation. Nodules were counted and diameter measured. It was observed that the soil contaminated with hydrocarbon inhibited growth and where there was growth, decreased shoot length. Nodules were also found to be absent in the contaminated soil.