Abstract

The effect of crude oil pollution of soil on the growth of plants and uptake of nutrients was investigated by growing corn (Zea mays L.) on a soil polluted by crude petroleum. The levels of the crude oil application varied from 0 to 10.6% by weight of soil. Three corn crops were raised in succession, each for a period of 6 weeks, in the same soil. The yields and plant contents of N, P, K, Ca, Fe, and Mn were determined. The soil was analyzed for organic C, total and available N, extractable P, and exchangeable K, Ca, Fe, and Mn after each cropping. Germination and yields were drastically reduced as the level of pollution increased. At 4.2% crude oil pollution level, the average reductions were 50% and 92% in germination and yield, respectively. The amount of organic C, total N, and exchangeable K, Fe, and Mn increased in the soil with level of crude oil addition, while extractable P, NO₃-N, and exchangeable Ca were reduced. The poor growth was attributed to suffocation of the plants caused by exclusion of air by the oil or exhaustion of oxygen by increased microbial activity, interference with plant-soil-water relationships, and toxicity from sulfides and excess available Mn produced during the decomposition of the hydrocarbons.

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