Growth performance of cassava –<i>Manihot esculenta crantz</i> in crude oil contaminated soil amended with compost of <i>Centrosema pubescens</i> Benth and inorganic fertilizer

Abstract

Studies on the performance of Manihot esculenta, Crantz (TMS 30572) in a crude oil polluted soil was investigated in the Botanic Garden of University of Port Harcourt. The soil samples were polluted at four different levels (0%, 2%, 4% and 6%) with crude oil and amended with organic supplement (decomposed Centrosem apubescens) and NPK fertilizer at the rate of 0.25Kg per 5Kg of soil to the various levels of crude oil contaminated soil, alongside a control. Quantitative observations showed that amelioration treatments (C. pubescensand NPK) recorded significant (P=0.05) increase in plant height, petiole length, leaf number, leaf area, fresh weight, dry weight and moisture content, than those of the control. Results of edaphic physico-chemical parameters showed that crude oil pollution significantly increased percentage total organic carbon, total organic matter and total hydrocarbon content (THC) at P=0.05 while pH, percentage total nitrogen, phosphorus and exchangeable bases (Ca, K and Mg) were significantly decreased at two weeks after pollution. The results also showed that the amendment treatments significantly decreased crude oil toxicity at different degrees at (P=0.05) by improving the nutrient content and decreasing the total hydrocarbon content of the soil.

Key words: Growth, Manihot esculenta, crude oil, pollution, Amendments, Contamination