Evaluation of crude oil contaminated soil on the mineral nutrient elements of maize (Zea mays L.)
Faculty of Agriculture, Delta State University, Asaba Campus, Delta State, Nigeria
This study evaluated the effects of crude oil contaminated soil on the mineral nutrient elements of maize. The study was conducted in Asaba and Ozoro locations of Delta State during the 2003 and 2004 planting seasons. Open pollinated AMATZBR y maize variety was used for the study. The experiment was laid out in a split-plot design replicated four times. Five crude oil concentrations (0, 5.2, 10.4, 20.8 and 41.6 mL) applied (ring application) at five weeks after planting (5 WAP) constituted treatments. The study location formed the main plot and the oil levels, the sub-plots. Grains were harvested at 14 WAP, shelled and analysed for mineral nutrient contents. Soil chemical properties were also analysed. The results showed that while total carbon, organic carbon, C/N ratio, phosphorus, calcium, magnesium and pH were significantly higher (p<0.05) in soils amended with crude oil, crude oil application to soil significantly reduced (p<0.05) electrical conductivity, total nitrogen and nitrate nitrogen in both locations. The highest values of 23.49 and 16.67 were recorded for C/N ratio in soils with 41.6 mL of oil while the lowest values of 8.83 and 9.72 were obtained in soils without oil treatment in Asaba and Ozoro locations, respectively. Significant differences (p = 0.05) were observed in the nutrient contents of maize seeds grown in soils amended with crude oil when compared with those grown in the uncontaminated sub-plots. The present study has demonstrated that crude oil contamination can improve soil content of some nutrient elements including Mg2+, K+, P, Na+ and exhibit a highly significant effect of reducing the chemical composition of maize seeds. © 2007 Asian Network for Scientific Information.