Characterization and Classification of Soil - Landform Features in Nigeria's Sokoto - Rima Floodplains

The study was to identify and classify soils in floodplains along the Wamakko area of Sokoto-Rima in Nigeria. After profiling, samples taken from each horizon were identified, characterized, and classified into four soil types: pedons 1 and 4 (Vertisols) and pedons 2 and 3 (Entisols). The results indicate an ideal pH range for most agronomic crops on the surface and subsurface horizons (pH 6.2–6.9). The organic carbon content was too low in all the studied horizons. The surface soil (0.71 to 1.39 g/kg) was relatively higher than the subsurface (0.88 to 1.41 g/ kg) soil horizons. The surface and subsurface soils were too low (0.043 to 0.120 g/kg) in total N and available P content (0.47 to 1.28 mg/kg) irrespective of slope positions. On a gently sloped (2–5%) gradient, the highest N (0.120 g/kg) and P (1.28 mg/kg) values were recorded. Calcium and magnesium were the dominant exchangeable bases in all slope positions. Surface (7.60 to 12.4 cmol (+)/kg) and subsurface (6.58 to 10 cmol (+)/kg) soils have medium cation exchange. The medium ranking of percent base saturation indicates the presence of basic cations in the exchange complex. On the surface horizons, they ranged from 49.03% in Pedon 4 to 65.25% in Pedon 1. On the subsurface soils, PBS ranged from 43.17% in the B horizon (Pedon 2) to 76.59% in the layer of the B horizon (Pedon 1). The nutrient content was higher in lower depositional areas. The interactions between soil and landforms become significant in agronomic management.