Remediation of petroleum polluted soils with organic manures and inorganic fertilizer and its effect on fluted pumpkin (Telefeira occidentalis) in Bayelsa State

Growth parameters of fluted pumpkin (Telefeira occidentalis) were examined to assess the effectiveness of remediating crude oil-polluted soils on application of organic manures and inorganic fertilizer in enhancing hydrocarbon-degrading bacteria (HDB) used in the bioremediation process in Bayelsa State. Two locations, Imiringi and Koloama, in Ogbia and Southern Ijaw Local Government Areas, respectively, known for crude oil spills were chosen for this study. Soil samples were collected from a depth of 0–30 cm, bulked for pot experiment in a screen house. Twenty-four plastic buckets, each holding 5 kg of soil and 0.5 kg of each of the treatments, were applied to each location, totaling 48 buckets. The experimental design was a 2 x 8 factorial arranged in a Completely Randomized Design (CRD), replicated three times. The data were statistically analyzed using Tukey's Test to distinguish significant differences at 5% probability level. The analyzed soil samples aimed to assess the impact of organic manures (cow dung and poultry droppings), inorganic fertilizer (NPK), and their combinations (CD + PD, PD + NPK, NPK + CD, and CD + PD + NPK) on the growth of fluted pumpkin (Telefeira occidentalis) and on the population of hydrocarbon-degrading bacteria (HDB) in the crude oil-polluted soils. In Imiringi, the HDB population (expressed in CFU/g) ranged from 8.30 x 105a to 1.14 x 106a, while Koloama, ranged from 5.74 x 105b to 7.36 x 105b, indicating significant difference between the two locations. The overall results showed high significant difference in growth parameters of fluted pumpkin (Telefeira occidentalis) with a few variations and HDB populations at different time (30, 60 and 90 days) suggesting the effectiveness of the application of these amendment materials.