Effect of organic inputs on soil properties, heavy metal content and maize root yield on spent engine oil contaminated soil

Abstract

The quality of soil resources and productivity are important indices for agricultural enterprise. A randomized complete block design (RCBD) experiment was set up to evaluate the effects of organic wastes on the chemical properties, heavy metal content and root dry matter yield of spent engine oil (EO) contaminated soil in Abakaliki, Southeastern Nigeria. The amendments included control (C), engine oil (EO) and animal wastes viz poultry droppings (PD) and rice husk dust (RHD). The wastes were applied at the rates of 10tha-1 in 2005 and its residual effect evaluated in 2006. Results from the study showed that C, PD and RHD significantly (p>0.05) improved the soil chemical properties relative to EO in 2005. Observed percentage organic matter (% OM) values in PD plots were 48, 89 and 158% higher than RHD, C and EO – amended plots, respectively. In 2006 the order of improvement in soil chemical properties was RHD > PD > EO > C. On the average C and RHD gave highest root dry matter yields (0.17 and 0.09 mgha-1) in 2005 and 2006, respectively. Results also showed higher heavy metal (Zn and Mn) values in EO plots relative to other amendments in both seasons. Observed heavy metal contents in all amendments (including EO) were within normal range in soil. The use of organic wastes to ameliorate the properties and productivity of engine oil polluted soil is recommend. 

Keywords: Engine oil, Heavy metal, organic wastes, soil, maize