The fixed nitrogen may compete for oxygen in the rhizosphere leading to release of toxic materials [41] and [42]For a compost to be used as a growth medium its C/N ratio should be between 12 and 18 [40] and [43]; however, a C/N ratio of 20 may be acceptable [39] and [42]. In this study, the C/N value of 10.1 ± 3.0 obtained was close to the suggested values required for agricultural purposes .Addition of compost to the contaminated soil samples resulted into higher values of C/N ratios in the two treatments.