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The influence of crude oil on maize growth and soil properties were evaluated in an Ultisol in Ihiagwa, Imo State, Nigeria. Four kg of air-dried soil samples were weighed into 4.5 litre plastic pots and treatment consisting of 6 levels of crude oil (0, 1, 2, 3, 4, and 5 t/ha) applied. Ten healthy maize seeds (Variety: Farz 27) were sown and the pots arranged in a completely randomized block design. Field trial was also conducted and three maize seeds (var. Farz 27) which were later thinned down to one plant per stand after germination were planted on plots measuring 4 x 4 m 2 . Crude oil treatments were applied at rates as used for the potted experiment, at three weeks after planting (WAP). The experimental design was a randomised complete block design with 3 replications. The experiment lasted for 12 weeks during which time, plant height and leaf area was estimated at a weekly interval. Plant mortality and dry matter yield were determined at the end of the 12 weeks growth period. Soil assays were run at beginning and end of study. Seed germination, plant height, leaf area and dry matter yield significantly decreased as the level of crude oil pollution increased. As crude oil pollution levels increased, soil pH also increased. There was no remarkable change in the level of soil organic carbon, nitrogen, exchangeable bases, exchangeable acidity, available phosphorus and effective cation exchange capacity as crude oil pollution increased in both studies. The primary way in which crude oil pollution reduces crop growth and performance would appear to be through reduction of seedling emergence and direct suffocation of plant roots by changing the redox potential and oxygen diffusion rates between soil system and the atmosphere. Keywords : crude oil, maize, soil property, pollution International Journal of Agriculture and Rural Development Vol. 5 2004: 91-100 |
