Impact of used motor oil on soil properties and yield indices of corn in Izzi, Ebonyi State, Nigeria

A lot of used motor oil is drained into the soil annually. The possibility of establishing impacts of used motor oil on soil properties and corn yield was studied with treatments i.e. 0 (control), 0.5, 1.0, 1.5, 2.0% for screen house and 0 (control), 8.0, 16.0, 24.0, 32.0% for field in demonstration farm of Ebonyi State University, Nigeria. The experiments were laid out using completely randomized design (CRD) and randomized completely block design (RCBD), with four replications having pot and plot dimensions of 30 x 30cm and 1.2 x 1.2, respectively. Uniform cultural practices were applied to all treatments. Statistical analysis was used to analyze soil and crop data. Results showed that application of treatments at 2.0 and 32.0% reduced gravimetric moisture content at significant (P <0.05) levels of 47 and 82% for the two studies. Available P was significantly reduced by 57 and 87%, K by 125 and 140%, N and K by 57 and 233% at 2.0 and 32.0% treatments compared to control. Crop yield indices were depressed at 400 and 150% at 2.0 and 32.0% treatments for dry matter and grain. Current study suggested that soil properties except pH and yield indices can be maximally degraded if used motor oil is applied at rates of 2.0 or 32.0% or minimally at 0.5 and 8.0%.