Biostimulation Potentials of Cow Dung on a Crude Oil Polluted Soil

Abstract

This field study was conducted to investigate the biostimulation effect of the application of cow dung to crude oil polluted soils. Four rates of crude oil (0, 100, 200 and 300 mL) and four rates of cow dung (0, 20, 40 and 60 g) were used respectively. It comprised of sixteen (16) treatment combinations replicated thrice, for a total of forty eight (48) plots with each plot measuring 1m x 1m. The experiment was laid out in a randomized complete block design. Bacteria, fungi and Physico-chemical properties of the soils were determined before pollution, two weeks after pollution and at the end of the experiment. The results for the physicochemical properties of soil indicate an increase in pH, carbon to nitrogen ratio (C:N), total organic carbon (TOC) and nitrogen (N) while Phosphorus (P) decreased as the level of crude oil increased despite remediation with cow dung. There was an increase in the bacterial count for both the control and the treatment groups. The result range from 1.3 X104 to 77.2 X104. The genus of bacteria identified were Pseudomonas, Bacillus, Micrococcus, Proteus, Clostridium and Nocardia species. Four isolates were gram-positive while 2 were gram negative. Five were rod-shaped while one was coccus in form, while the fungal isolates are Cladosporium, Pichia, Aspergillus, Fusarium species. Soil analysis during the experiment revealed a general negative correlation coefficient implying enhanced remediation during the trial periods.