Uptake and Distribution of Total Petroleum Hydrocarbon by Sunflower from Crude Oil Contaminated Soils Using Agro-Industrial Wastes as Soil Amendments

This study investigated the growth performance of sunflower (Helianthus annuus L.) under different concentrations of petroleum hydrocarbon-contaminated soils. This was with a view to assessing the remediating potentials of the test crop when different rates of agro-industrial wastes were used as soil amendments. The experiment was conducted in the greenhouse of the Faculty of Agriculture, Obafemi Awolowo University, Ile-Ife. It was a 5 x 3 x 3 factorial complete randomized design, consisting of 135 polythene pots, each containing five kg of sandy topsoil. Poultry waste and ashed sawdust in different ratios [0:100; 25:75; 50:50; 75:25; and 100:0] gave five manure mixtures, which were applied at three levels (0, 4, and 8 t ha⁻¹) as soil amendments. These manures significantly (p < 0.05) increased the uptake and accumulation of total petroleum hydrocarbon in the root (0.19-0.46 mg kg⁻¹), shoot (0.75-1.71 mg kg⁻¹), and grains (0.13-0.26 mg kg⁻¹) of sunflower; however, with superior influence from 8 t ha⁻¹ containing higher poultry waste and at 1% crude oil soil contamination. The study concluded that sunflower has potential for cleaning up petroleum hydrocarbons from crude oil-contaminated soil, particularly when a high composted poultry waste proportion in the manure mixtures was used as a soil enhancer in the humid tropical climate.