African Journal of Biotechnology Vol. 6 (11), pp. 1332-1337, 4 June 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Determining the tolerance level of Zea mays (maize) to a crude oil polluted agricultural soil

Josiah M. Ayotamuno* and Reginald B. Kogbara

Department of Agricultural and Environmental Engineering, Rivers State University of Science and Technology, P. M. B. 5080, Port Harcourt, Nigeria.

*Corresponding author. E-mail: mjayotamuno@hotmail.com

Accepted 9 May, 2007

This research sought to investigate the tolerance level of Zea mays (maize) on a crude oil contaminated soil using indices of plant performance such as plant height, leaf area and fresh cob yield. In the experiments described, conditions of a major spill were simulated by pouring different amounts of crude oil on experimental pots containing agricultural soil. Maize seeds were then grown amidst adequate fertilizer application and irrigation. The results of the study revealed that maize can survive soil contamination of about 21% (similar to 177 000 mg/kg) and still produce fresh cob yield of about 60% than on normal soil. There was a stimulated increase in fresh cob yield, than that obtained on normal soil at 12.5% soil contamination (similar to 112240 mg/kg). Hence, contaminant concentrations of 112 240 mg/kg and 177 000 mg/kg are identified as the ‘optimum yield limit’ and ‘lethal threshold’ respectively for maize growing on crude oil polluted soils. These results highlight the fact that, while concerted efforts should be made to remedy petroleum-contaminated agricultural soils, certain crops like maize can still produce beneficial yield in the presence of good soil management practices.

Key words: Contaminant concentrations, crude oil contamination, fresh cob yield, lethal threshold, optimum yield limit, plant height.