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A study was conducted at the Department of Crop and Soil Science teaching farm, University of Port Harcourt to examine the effect of lubricant automobile oil on soil physical properties and performance of Abelmoschus esculentus for a period of eight weeks. Composite soil samples were collected randomly at depths of 0-20 cm. The soil was placed in 10 kg buckets. Spent lubricant oil collected from the automobile mechanic workshop was used to contaminate the soils at 0, 2, 4, and 6% w/v. Two varieties of Okra V1 (local) and V2 (Clensom spineless) were used. Three okra seeds were planted two weeks after contamination and later thinned to two. Each treatment was replicated thrice; the design was completely randomized. The results showed that the spent oil had no effect on per cent germination on V1 in the treatments and at 0 and 2% contamination for V2. As contamination increases, the percent germination of V2 decreases to 83.3 and 72.2% for 4 and 6% respectively. Increase in spent oil contamination reduced the height of the two varieties. V2 was more affected as percent contamination increases in week 1, thereafter, improves better than V1. No significant (p>0.05) difference in number of plant leaves even as contamination increased except in weeks 3, 5 and 6. Number of leaves decreased with increase in level of contamination and increases as the weeks increased in both varieties. Lowest number of leaves observed at 6% and highest at control in the two varieties. Leaf area of both varieties significantly reduced in contaminated over control though varietyV2 was significantly (p<0.05) higher than V1. Contamination of the soil did not change the textural class of the soil. Significant decrease was recorded in hydraulic conductivity of the soil between the contaminated and control. As the contamination level increased, hydraulic conductivity decreased. Contamination of the soil with lubricant oil increased the soil bulk density. The effect of hydrocarbon contamination was pronounced as there was delay in plant germinations, poor and stunted growth of the two varieties, and yellowing of leaves at the seventh and eighth weeks, especially at 6% contamination on both varieties.
Chukwumati et al. (Wed,) studied this question.