Pedological Characterization and Taxonomic Classification of Schist-Derived Soils in Erinmope-Ekiti, Southwestern Nigeria

Understanding soil variability along landscapes is essential for interpreting pedogenesis, improving soil classification, and supporting sustainable land management. This study characterized and classified schist-derived soils along a toposequence in Erinmope-Ekiti, southwestern Nigeria. Six representative pedons, comprising two at each slope position, were described and sampled by genetic horizons, for laboratory analysis of selected soil properties using standard procedures. The soils were moderately deep to deep (81 to 146 cm) and showed clear horizon differentiation. Surface horizons were predominantly sandy loam to loam, whereas subsurface horizons were dominantly clayey, reflecting pronounced clay translocation and accumulation. Clay films and textural differentiation provided morphological evidence of argillic horizon development, particularly in the middle-slope pedons. The soils were acidic to slightly acidic (5.36 to 6.77), while base saturation ranged from 50.77 to 94.48%. Sand and clay showed relatively low variability, whereas K, OC, OM, and exchangeable hydrogen exhibited greater variability. Lower-slope pedons recorded higher pH, OC, available phosphorus, exchangeable bases, ECEC, and base saturation, indicating the influence of downslope redistribution and accumulation of soil materials. Significant relationships among texture, OC, pH, and exchangeable bases further demonstrated the interdependence of soil properties along the landscape. Under USDA Soil Taxonomy, the soils were classified as Typic Paleustalfs, Typic Haplustalfs, and Aquic Haplustalfs, while under WRB they were classified as Haplic Lixisols and Gleyic Lixisols. The findings demonstrate that topography strongly influences soil development, property distribution, and taxonomic differentiation of schist-derived soils in the study area, providing a useful basis for soil evaluation, management, and agricultural planning.