Characterization and Classification of Paleosols in Part of South India

Paleosols, which are known as soils formed during the past climatic conditions, part of south India in Anantapur district of Andhra Pradesh are described here. Morphological properties of five pedons (P1 to P5} like depth, colour, structure, texture, presence of clay cutans, etc. and physical and chemical properties such as particle size distribution, pH, acidity, exchangeable bases and CEC were studied and used to identify Paleosols. Colour of these soils is redder than 5 YR and have patchy clay skins. Sand/silt, fine sand/total sand and very fine sand/total sand ratios showed discontinuity between horizons as a result of several erosion and deposition cycles. Silt/clay ratios are lower, suggesting dominance of secondary over primary minerals. The KCl-pH values are much lower than water-pH values, though the acidity measured by 1 N KCl is negligible. However, BaCl₂-TEA acidity gives higher values due to large amounts of AI. Cation exchange capacity, ECEC and base saturation (by sum of cations} values are usually lower suggesting that the soils are sufficiently leached. The soils were classified as Rhodustalfs (p1, P3, P5) and Haplustalfs (P2, P4) as per Soil Taxonomy and as Luvisols (P1, P2), Acrisols (P3) and Alisols (P4, P5) as per FAO/UNESCO system. A new Ultic subgroup has been proposed under Rhodustalf great group. It has been suggested that the weathering products of previous humid climate were eroded as evidenced from mostly shallow or moderately deep soils. It is concluded that Alfisols in this part of south India are Paleosols.