Evaluation of Organic Wastes on Some Selected Soil Physical Properties and Yield of Maize (Zea Mays L.) in an Ultisol of South Eastern Nigeria Previously Contaminated with Spent Lubricant Oil

This study conducted in Abakaliki during 2007 and 2008 cropping years to evaluate the effect of organic wastes on soil physical properties and yield of maize (Zea Mays L.) in an ultisol previously contaminated with spent lubricant oil. The soils were contaminated with twenty (20) litres of spent lubricant oil sourced from the mechanic village Abakaliki and uniformly sprayed on each plot and amended with saw dust, unburnt rice husk dust and burnt rice husk dust. The control plot had no spent lubricant oil contamination. The experiment was laid out in Randomized Complete Block Design (RCBD). An improved variety of maize (Oba super II) was used as a test crop. The result indicated that there were (P<0.05) significant differences among the treatments and on grain yield, bulk density, hydraulic conductivity, macro porosity, aggregate stability and mean weight diameter. Similarly, the result showed that unburnt rice husk dust treatment recorded 5.08%, 25.49%, 46.43% and 25.35% increments for hydraulic conductivity, total porosity, macro porosity, respectively over control treatment. The result therefore, proved that remained organic wastes in the soil contaminated with spent lubricant oil could improve soil physical properties and agronomic yield of maize. Keywords: Ultisol, Soil physical properties, spent lubricant oil, yield of maize, Abakalik