Effect of Microbial Consortium and Organic Stimulant on Maize Growth in Bitumen-Polluted Soil

This study evaluated the growth rate of maize (Zea mays) in bitumen-polluted soil and assessed the effectiveness of bioremediation treatments in supporting its growth. The bitumen sample was collected from Agbabu, Odigbo Local Government Area of Ondo State, and unpolluted soil was collected from a control area. The raw bitumen was mixed with the soil using standard methods. A consortium of previously identified hydrocarbon-degrading bacteria, along with a treatment incorporating fish pond waste (FPW) as an organic stimulant, was introduced into the polluted soil. A screenhouse experiment was conducted with five treatments, each replicated three times, for a total of fifteen experimental units. Each treatment consisted of 5 kg of sieved soil in a plastic pot, and three maize seeds were sown per pot, later thinned to one plant per pot two weeks after sowing. Growth parameters (number of leaves, plant height, leaf length, leaf width, and leaf area) were measured biweekly from the third week until harvest. The results showed varying responses across the different treatments. The bitumen-polluted soil treated with the bacterial consortium and biostimulant (FPW) improved leaf area and plant height over 10 weeks. A notable improvement in plant height was observed when the bacterial isolates were biostimulated with FPW. Leaf width was consistently enhanced by both the bacterial consortium alone and the consortium combined with the organic stimulant throughout the growth period. This study concluded that both the bacterial consortium and organic amendment (fish pond waste) had a positive impact on the growth performance of maize in bitumen-polluted soil.