Physical and Geotechnical Properties of Termite Mound Soils of Coptotermes acinaciformis and Nasutitermes walkeri in Two Ecological Zones of Bauchi State, Nigeria

Abstract

Termite-mound soils may possess physical and geotechnical characteristics relevant to construction and soil management. This study compared mound soils attributed to Coptotermes acinaciformis and Nasutitermes walkeri with adjacent control soils from nine communities in Bogoro, Bauchi, and Katagum Local Government Areas of Bauchi State, Nigeria. Moisture content, liquid limit, plastic limit, plasticity index, specific gravity, organic matter content, pH, and colour were evaluated using the reported laboratory procedures. Across the three areas, N. walkeri mound soils had the highest moisture contents (26.05–27.80%) and plastic limits (17.24–18.60%). C. acinaciformis mound soils had moisture contents of 17.70–18.00% and plastic limits of 16.60–16.90%, whereas control soils had moisture contents of 11.11–12.10% and plastic limits of 11.00–12.05%. Organic matter contents were 4.05–4.44 g/kg in N. walkeri mound soils, 4.00–4.50 g/kg in C. acinaciformis mound soils, and 2.13–2.33 g/kg in control soils. The reported analysis of variance indicated no statistically significant differences (p > 0.05) among soil groups within each Local Government Area. The mean reported plasticity index of N. walkeri mound soils was 8.99%, suggesting possible suitability for selected sub-base applications. However, several tabulated liquid limits were lower than the corresponding plastic limits; therefore, the plasticity indices and related engineering interpretations require verification against the original cone-penetrometer records before practical application.