Characterization and Classification of Selected Soils Formed on a Planar Surface in Wukari, Nigeria

This study investigates the properties and variability of selected pedons in Wukari, Nigeria, focusing on their characterization and classification. Field soil profile description and laboratory analyses were conducted to assess morphological, physical, and chemical properties. Soil samples were collected from identified horizons and analyzed for selected properties. Genetic classification was performed, and statistical procedures such as correlation and Linear Discriminant Analysis (LDA) were applied to examine soil property relationships and horizon differentiation. Morphological analysis revealed variations in horizon depth and color, with Ap horizons exhibiting darker colors and shallower depths in Pedon 2 (14 cm) compared to Pedons 1 and 3 (20–22 cm). Textural analysis showed a transition from sandy loam in surface horizons to sandy clay loam in Bt horizons, indicating clay translocation. Bulk density increased with depth (1.21–1.45 Mg m-3), while porosity declined due to compaction. Organic carbon and total nitrogen were highest in Ap horizons (10.9 - 14.40 g kg-1 and 1.17 – 1.31 g kg-1 respectively) and decreased with depth. High base saturation (>85%) across all horizons indicated strong nutrient retention. The soils were classified as Alfisols (Typic Haplustalfs and Typic Paleustalfs) in the USDA system, corresponding to Haplic Luvisols in the FAO system. Key classification indicators included the presence of an argillic horizon and base saturation exceeding 50%. Statistical analysis effectively differentiated soil horizons, with sodium content and total nitrogen as key discriminants. The LDA model achieved 81.82% accuracy, emphasizing the importance of horizon-specific management for sustainable soil use even in planar surfaces.