Nwakwasi, Ngozi Livinus2026-06-022026-06-022016-06Nwakwasi, N. L. (2016). Modelling of major soil nutrients depletion in crude oil contaminated soil [Unpublished Master's Thesis]. Federal University of Technology Owerri, Nigeriahttps://repository.futo.edu.ng/handle/20.500.14562/2795This thesis is for the award of Doctor of Philosophy (PhD.) in Water Resources in EngineeringModeling of major soil nutrients depletion in crude oil contaminated soil was carried out, using field experimental data generated from Research Farm Soil at the Federal University of Technology, Owerri, Imo State, Nigeria. The main objective of the study was to investigate the variation of nutrients, curde oil concentration and bacteria with time in the laboratory. To develop models for prediction of nutrient depletion with time and see how the models can be applied in field and bioremediation activities. The soil was artificially polluted with crude oil (bonny light) of different volumes/wt (i.e. 0.5, 1.0, 1.5, 2.0 and 2.5 litres per 10kg of soil), equivalent to 629 barrels/hectare, 1258 barrels/ha, 1887 barrels/ha, 2515 barrels/ha and 3144 barrels/ha respectively. Some physicochemical properties that reflects major soil nutrient content and fertility status (Nitrogen, Phosphorous, Potassium, Organic Carbon, Organic Matter and Soil pH) were determined, using standard methods. Results from the different levels of crude oil pollution over time showed that nitrogen content depleted from 0.287 to 0.123 within the first 14 days after pollution. Nitrogen content of the control sample was about three times higher than the values of nitrogen content at other various levels of crude oil pollution (0.021/0.0079) when averaged over a period of time (112 days). Similar results were obtained for phosphorous content which depleted five times over the control value when averaged over a period of time. Potassium content also showed a significant decrease from the control value, and was about 3 times lower when averaged over a period of time. There was, however, a slight increase in the organic carbon and organic matter content, which was about 1.5 times higher than the control value. The model values of major soil nutrients obtained from the various model equations were very close to experimental values. Hence the models are all suitable for determining the various contents of Nitrogen, Phosphorous, Potassium, Organic Matter and Organic Carbon in crude oil polluted site. The agitation/complaints over polluted farm lands in the Niger Delta region can now be resolved within the shortest possible time by utilizing the findings and model equations developed from the study. Hence, the cut-off between what really constitutes a poisonous dose and no-effect or tolerable dose in crude oil contamination can be determined using the models.enAttribution-NonCommercial-ShareAlike 4.0 InternationalCrude oilpollutionsoil nutrientdepletioncontaminated oilmodel and soil fertilityDepartment of Civil EngineeringMaster’s Thesis