Rubber Effluent Bio-Analyses and Its Impacts on the Microbial Community Structure of the Soil in Calabar, Nigeria

The study was carried out by artificially polluting an agricultural soil in Calabar with varying concentrations (0 ml, 250 ml, 500 ml, 1000 ml and 2000 ml) of rubber effluent, in which 0 ml served as control, with the aim of assessing their effect on soil microflora and fertility. The polluted soil was analysed in terms of the following parameters; microbial population, soil pH organic matter, total nitrogen, available phosphorus, electrical conductivity, calcium, magnesium, potassium, sodium, effective cation exchange capacity, exchangeable acidity and base saturation. In the polluted soils, the total heterotrophic bacteria, total heterotrophic fungi and total heterotrophic actinomycetes increased significantly (p<.05) with a decrease in the concentration of pollutants. The total heterotrophic bacteria and total heterotrophic actinomycetes showed significant reduction with an increase in the length of pollution while total heterotrophic fungi did not show difference (p>.05) over the duration of pollution. Microbial species isolated from the polluted soil were Pseudomonas sp., Bacillus sp., Staphylococcus sp., Micrococcus sp. Flavobacterium sp., Mucor spp., Fusarium spp., Penicillum spp., Aspergillus spp., Rhizopus spp., and Streptomyces spp. In the polluted soil, pH, organic matter, total nitrogen, potassium, available phosphorus, magnesium and sodium, showed significant differences (p<.05) in their values with the control, while calcium, electrical conductivity, base saturation, effective cation exchange capacity, and exchangeable acidity did not show significant difference (p>.05) with that of the control. The results of this study revealed that light application of rubber effluent could enhance microbial proliferation and thus, increases soil fertility, while a heavy application inhibits the same.