Soil faunal activity of an oil-polluted tropical alfisol amended with organic wastes as determined by micromorphological observations

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment Vol. 39; no. 1; pp. 46 - 57
• Main Authors: Adesodun, J.K., Davidson, D.A., Mbagwu, J.S.C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-05-2008; [Amsterdam]: Elsevier Science; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Alfisols; Biochemistry and biology; biodegradation; Biological and medical sciences; Bioremediation; cattle manure; Chemical, physicochemical, biochemical and biological properties; feces; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; heavy metals; industrial oils; Organic wastes; Other nutrients. Amendments. Solid and liquid wastes. Sludges and slurries; Physics, chemistry, biochemistry and biology of agricultural and forest soils; pig manure; poultry manure; soil amendments; Soil and water pollution; soil fauna; Soil faunal activity; Soil micromorphology; soil morphological features; soil organic matter; soil pollution; Soil science; Soil-plant relationships. Soil fertility. Fertilization. Amendments; tropical soils; Used-lubricating oil; waste utilization; Zoology (interactions between soil fauna and agricultural or forest soils); Nigeria; West Africa; Africa; Used-lubricating oil; Soil faunal activity; Organic wastes; Bioremediation; Soil micromorphology; Lubricating oil; Organic waste; Tropical zone; Pollution control; Alfisols; Ecology; Soil pollution; Tropical soil; Soil fauna; Animal activity; Soil science; Organic amendment; Micromorphology
• ISSN: 0929-1393; 1873-0272
• DOI: 10.1016/j.apsoil.2007.11.006

This study evaluates the effect of used-lubricating oil (spent oil) and organic nutrient supplements as derived from animal droppings on faunal activity as expressed in the incidence of faunal excrement and related micromorphological features. This approach allows the effects of the treatments to be evaluated even if the organisms are no longer present. The main-plot treatments included control (C), cow dung (CD), poultry droppings or manure (PM) and pig droppings or waste (PW) each at 10
Mg
ha
−1 each. The sub-plot treatments were control (no applied contaminant), 0.5%, 2.5% and 5% spent oil (SP) applied at 10, 50 and 100
Mg
ha
−1 (w/w), respectively. Residual oil blobs were clear in soil thin sections and the results from point counting demonstrated a significant reduction in oil content following the addition of organic wastes to the polluted soils. Spheroids of organic material interpreted as excrement from enchytraeids dominated thin sections from the control and treated plots. Other observed excrement types were undifferentiated (fused) excrements formed from coalesced or “aged” excrements. The occurrence of the total excrements showed no faunal activity in plots polluted with 0.5%, 2.5% and 5% SP, indicating elimination of soil fauna by oil pollution. Results from point counting of excremental features indicated significant faunal activity with CD, PM and PW treatments, and in oil-polluted plots supplemented with organic wastes. The treatments with PM and PW were better than CD in stimulating oil degradation. Treatments also showed a reduction in total porosity with an increase in oil concentrations whereas no significant improvement was observed in oil-polluted soils amended with organic wastes. However, addition of the organic wastes to oil-polluted soils showed evidence of increased decomposition in the order PM
>
PW
>
CD. In conclusion, the substantial reduction in soil faunal activity as a result of oil treatment confirmed the deleterious effect of petroleum products on living organisms, but the addition of PM and PW were effective in ameliorating this negative impact.