Urban Land Use Influence on Soil Bacterial and Fungal Concentrations within and Outside the Urban Core of Benin Metropolis

Abstract

Soil bacteria and fungi play significant roles in the soil ecosystem. However, the influences of land use on them are among the least studied aspects in tropical urban soils. This study evaluated the impact of urban land use on soil bacterial and fungal concentrations within and outside the urban core of Benin Metropolis. Using the systematic random sampling approach, a total of 60 soil samples were collected from five urban land use types (sawmill factory, horticultural garden/arable farm, open market, municipal waste open dumpsite, and auto mechanic site) across both the topsoil and subsoil. Descriptive and inferential (ANOVA and Student’s t-test) statistics were used to analyze the data. The results showed that within the urban core, the highest total heterotrophic bacterial count (THBC) occurred in the municipal waste open dumpsite (15.33 × 105 cfu g-1 ) and open market (20.60 × 105 cfu g-1 ) across both topsoil and subsoil. Outside the urban core, THBC was highest in the municipal waste open dumpsite, with values of 17.47 × 105 cfu g-1 in the topsoil and 9.67 × 105 cfu g˗1 in the subsoil. The findings indicated that within the urban core, the highest total heterotrophic fungal count (THFC) occurred in the sawmill factory (17.67 × 103 cfug-1 ) in the topsoil, and in the open market (8.33 × 103 cfu g-1 ) in the subsoil. Outside the urban core, THFC was greatest in the municipal waste open dumpsite, with values of 7.33  × 103 cfu g-1 in the topsoil and 5.67 × 103 cfu g-1 in the subsoil. The study concluded that among the land uses, municipal waste open dumpsites had the greatest influence on bacterial populations, whereas sawmill factories had the most pronounced effect on fungal concentrations. Furthermore, soil depth significantly influenced the vertical distribution of both THBC and THFC across the topsoil and subsoil