Characterization and classification of landforms and soils over basaltic terrain in sub-humid tropics of central India

In the present investigation, an attempt has been made to analyse the landform and soil characteristics of Ringnabodi watershed of Nagpur district in subhumid tropics of central India for their characterization, classification and analysis of their relationships. The analysis of satellite data and field investigation reveal summit crest, escarpments, isolated mounds, denuded plateau, foot slopes, upper piedmont, lower piedmont and narrow valley floor as dominant landforms. The slope varies from level to nearly level (0–1%) to steeply sloping (30–50%) land. With changing topographic position, the depth of soil changed from 33 to 140 cm and the coarse fragments decreased from 61 to 2%. The soils developed on topographically higher elevation have dark brown (7.5 YR hue) and those developed on lower elevation have dark brown to very dark gray and very dark grayish brown (10 YR hue) colour. Soils at higher elevation have clay loam texture, whereas the low-lying areas have clayey textural class. Higher available waterholding capacity (AWC 199 mm) is found in lowlying area and low to medium (AWC 68 mm) is noticed in the soils developed on higher elevation. The reaction (pH) of the soils is slightly acidic (6.0 to 6.5) in nature on summit crest, escarpment and isolated mounds and remaining soils from denuded plateau to narrow valley floor are slightly alkaline (7.7–8.3). Increasing trend of electrical conductivity (EC) with depth is noticed and it ranges from 0.06 to 0.25 dS m⁻¹. The cation exchange capacity (CEC) of the soils of the area varies from 25.6 to 57.1 cmol(p⁺)kg⁻¹. Clay, CaCO₃ and base saturation increases with decreasing elevation and slope. Lithic Ustorthents on summit crest and escarpment, Lithic Haplustepts on isolated mounds, Typic Ustorthents on denuded plateau and foot slopes, Typic Haplusterts on upper and lower piedmonts and Vertic Haplustepts on narrow valley floor are the major soils observed.