DEPARTMENTOFSOILSCIENCE

The experiment was conducted at Faculty of Agriculture experimental farm, located at the back of the new faculty building of the University of Benin, Benin city, with the aim to determine the potentiality of mushroom in the removal of heavy metals from spent engine oil polluted soils. The experiment was a 5m x 3m experiment in completely randomised design with 3 replications. The spent engine oil was applied and was left for 2 weeks before mushrooms were added to the soil. The Soil samples were then analyzed using Standard laboratory analytical methods. Some of the physical and chemical parameters of the soil tested were pH, total nitrogen, total organic carbon, available phosphorus, total hydrocarbon content, potassium, calcium, magnesium, and sodium. The result showed that most of the parameters tested including pH, total nitrogen, total organic carbon, available phosphorus, total hydrocarbon content, potassium, calcium, magnesium, and sodium increased at all levels of spent engine oil treatments, while the exchangeable acidity decreased at all levels of spent engine oil treatments, thereby breaking down complex detrimental element from the SEO which is finally absorb by the plant used. The result from the experiment was not significant due to the limited time used in carrying out the experiment.

The saturated hydraulic conductivity in this work was determined using its relationship with other soil parameters. A soil survey process was used to determine the Ksat of two mapping unit found in the site. Each mapping unit was represented with a pedon from which soils were collected using a soil auger and core sampler. Ksat was determined in the laboratory using the constant head method, the primary objective of this study was to evaluate the relationship between saturated hydraulic conductivity and other soil routine properties of soils found at the AGR 305 Farm to see if a prediction equation could be derived and used in the determination of saturated hydraulic conductivity in soils with similar properties.
The result showed that the study site in mapping unit 1 and mapping unit 2 have parameters
that correlated differently. In mapping unit 1, it was observed that phosphorus (0.736), CEC (0.879), Base saturation (0.831), clay(0.726) correlated postively while sand (-0.766), aggregate stability (-0.614) correlated negatively and was used to determine the saturated hydraulic conductivity of that mapping unit. But in mapping unit 2, ph(-0.858), organic carbon (-0.884), organic matter (-0.770), total nitrogen (-0.771) correlated negatively while bulk density (0.851) correlated positively and was used to determine the saturated hydraulic conductivity for that soil type