Soil-Physiographic Relationship on a Transect in Southern Rajasthan

Five pedons representative of different physiographic regions in Dungarpur district of Rajasthan were studied to establish soil-physiographic relationship. The soils on very steeply slopping side slopes are shallow, excessively drained, and coarser in nature, whereas the soils of gently sloping pediment and undulating plains are deep, finer in texture and have better structural development. Clay cutans andfine clay to total clay ratio provided evidence of argillic horizons in the soils on very gently slopping and nearly level plains. Sand/silt ratio (> 0.2mm) suggests lithological discontinuity between overlying Ap and underlying Bt horizon. The depth distribution of A1₂O₃, Fe₂O₃ and clay provided confirmative evidence of clay illuviation. The decreasing trend of fine sand/total sand, CEC-claylclay, Al₂O₃/Fe₂O₃ molar ratio indicated that the soils on the stable landscape are more weathered compared with other soils.