Yield and quality of maize from spent engine oil contaminated soils amended with compost under screenhouse conditions

Abstract

Abstract The study investigated the effects of poultry manure compost (PMC) on the growth performance and yield of maize (Zea mays L.) when cultivated on spent engine oil (SEO) contaminated soil with a view to assessing its nutritional composition. The experiment consisted of three SEO treatments (0%, 1% and 2% w/w) with six levels (0, 2, 4, 6, 8 and 10 t ha-1) of PMC applications. Each treatment was replicated thrice and arranged in a 3 × 6 × 3 factorial completely randomized design to give a total of 54 pots. At full physiological maturity, maize grains were harvested and threshed manually for analysis. As the bioavailability of metals increased with increasing PMC, their uptake by maize plants was enhanced. The soil amended with 10 t ha-1 and contaminated with 1% SEO recorded the highest uptake rates of 1.761 × 10-2, 2.345 × 10-2 and 4.285 × 10-2 day-1 for Fe, Cu and Pb respectively. Also, the significantly (P<0.05) highest yield of maize (5.8 t ha-1) and the highest nutritional values of crude protein (11.27 g 100 g-1) and crude fibre (2.71 g 100 g-1) were obtained with zero SEO soil contamination at 10 t ha-1 PMC applications. There was evidence of yield and nutritional quality reduction of maize when cultivated on SEO contaminated soils with or without poultry compost fertilization