Morphological Characterization and Classification of Soils in Khana Area of Niger Delta, Nigeria

The soils in Khana area, Rivers State, were classified using the USDA Soil Taxonomy Classification System. Seven soil pedons were sampled, focusing on genetic horizons, along three transects and on five major land-use types. All pedons displayed Cambic subsurface horizons beneath epipedons. USDA Soil classification of pedons in Khana area are mainly Inceptisols and Ultisols. Soil pH ranged from moderately acidic (5.7 – 6.9) across various pedons. Total Nitrogen content varied significantly (p < 0.05), with cultivated land having the lowest (0.4g/kg) and forested soil having the highest (2.3g/kg) surface horizon values. Exchangeable bases (Potassium, Magnesium, Calcium, Sodium) also varied significantly (p < 0.05), spanning from 0.28 - 2.00 cmol/kg; 0.01 - 1.96 cmol/kg; 0.50 - 2.00 cmol/kg; and 0.25 - 1.64 cmol/kg for Potassium, Magnesium, Calcium, and Sodium, respectively. Bulk density, saturated hydraulic conductivity, and mean weight diameter differed significantly (P < 0.05) among land-use types. Saturated hydraulic conductivity ranged from 1.0 - 54.0 cm/hr, bulk density from 1.64 – 1.59 g/cm³, and mean weight diameter from 1.677 – 0.597. Particle size distribution ranged from 437.0 - 787.0 g/kg; 137.0 - 300 g/kg; and 46.0 - 350.0 g/kg for sand, silt, and clay fractions, respectively. Clay content increased with depth. Among the pedons, four were generally Ultisols (Typic Hapludolls), while three (from Eeke, Taabaa, and Okwale communities) were Inceptisols (Arenic Eutrudepts). Overall, this study provides insight into the soil properties of Khana area, enabling recommendations for optimized crop cultivation, and soil management in poorly drained subsoil regions