Soil-Physiographic Relationship in a Transect over Basaltic Trap

The relationship between physiography and the associated soils has been studied. Five physiography units, viz., hill slope, upper piedmont, lower piedmont, piedmont plain and coastal plain were identified in a transect over basaltic trap area. The soils over elevated topography (75-150m MSL) are shallow to moderately shallow excessively to well drained, dark yellowish brown to dark grayish brown, medium textured and exhibit poor profile development while those on lower topography (0-25m MSL), are deep to very deep, moderately well drained to poorly drained, dark brown to brown and fine textured and exhibit good profile development. The soils over moderately elevated topography (10-75m MSL) posses the intermediate characteristics between higher and lower elevated topography and moderate profile development. There was a gradual increase in EC, CaCO₃, CEC, exchangeable, water-soluble cations and SAR of soils with the decrease in topographic levels. Soils occurring at higher altitude lack diagnostic horizon and were classified as Entisols. While those occurring on depositional landscapes have well developed diagnostic horizons and were classified as Inceptisols.