Soil Chemical Properties and Performance of Groundnut (Arachis hypogaea) on Crude Oil Polluted Soil

Abstract

The experiment was carried out in the Faculty of Agriculture Teaching and Research Farm, Ignatius Ajuru University of Education (IAUE) Ndele campus in Rivers State, Nigeria. The study investigated the soil chemical properties and performance of groundnut (Arachis hypogaea) on crude oil polluted soil. The experiment was laid out in a Randomized Complete Block Design and replicated 3 times. 10kg of sandy top soils (0-15cm depth) were collected from the research farm site into 48 polythene bags. The crude oil contamination was applied at the rate of 0ml (control), 10ml, 20ml, and 40ml per polythene bag before sowing the groundnut seed sourced from the local market. Data collected were subjected to the analysis of variance (ANOVA) using statistical software, SPSS version 20.1 and the significant treatment means were compared using the Duncan multiple range test (DMRT) at P≤0.05. Results showed that increasing the crude oil rate significantly (P≤0.05) decreased germination percentage, leaf area and groundnut yield. At 10ml and 20ml, number of leaves and plant height of the groundnut seedling increased but at the same rate it significantly (P≤0.05) decreased the number and weight of the groundnut seed and pod. At 40ml of crude oil contamination, the vegetative growth and yield of the groundnut plant reduced significantly (P≤0.05). It was observed that the pH decreased from 6.82 at planting to 6.69 at harvest for the control, and increased with increasing crude oil concentration at planting and harvest respectively. Nitrogen and organic matter were at least at 40ml but exceeded control at 10ml and 20ml application at planting. Also at planting, increasing crude oil rates significantly increased cation exchange capacity and percentage base saturation when compared to control and then significantly reduced electrical conductivity. Crude oil concentration did not significantly influence phosphorus and potassium at planting. At harvest, increasing crude oil rate increased pH, organic matter, and percentage base saturation but decreased phosphorus, potassium, cation exchange capacity and electrical conductivity. Crude oil reduced the performance of groundnut plants and influenced the chemical properties of the soil. It is recommended that further study be conducted to determine the chemical composition of the groundnut plant at harvest under similar conditions.