Abstract

This study was carried out on spent oil degraded soil using bio and inorganic fertilizers to attempt its restoration using Manihot esculenta Crantz., as test crop under Screen House conditions. Nine (9) kg of spent oil contaminated and uncontaminated soils were each crushed and weighed into 10 L plastic pots with Camry Premium Scale (Model J100/2839). All pots were perforated at the base to drain excess water. The pots were arranged in completely randomized block design and replicated three times. Cow dung, Human effluent and NPK fertilizer were applied to the soil at the rates of 50, 100 and 150 g two weeks after planting cassava stems. The following morphological parameters were used to assess plant growth: plant height, leaf length, leaf width, stem diameter, number of nodes, leaf fall were taken for 20 weeks and fresh and dry weights of tubers immediately after harvest and drying, respectively. The highest growth was recorded in uncontaminated soil (control) which had the highest mean plant height (52.77±17.22 cm); followed by soil treated with 150 g NPK with a mean plant height of 42.47±24.70 cm. Soils treated with human effluent at 50 g had the least plant height of 17.08±5.05cm. The best performance of the cassava test species was recorded in the spent oil contaminated soil amended with NPK and closely followed by contaminated soil remediated with cow dung treatment. The findings of this study revealed that addition of bio and inorganic fertilizer was useful in remediating spent oil polluted soil.

Key words: Soil amendment, degraded soil, bio- and inorganic fertilizers, Manihot esculenta.