Characterization of Old Alluvial Soils of Sone Basin

The old alluvial soils on upland physiography under immediate influence of the river Sone are characterized by yellowish brown colour, loamy sand to sandy loam texture, presence of mottles and concretions, low organic carbon, slightly acidic to neutral reaction.(pH 6.4–6.7), lower CEC and exchangeable Mg and Na; while the soils on upland under immediate influence of Sirisia canal (with high finer load emerging from the sone) are light olive in colour, clay loam to clay, low in organic carbon, neutral to slightly alkaline in reaction (pH 6.7–7.5) and intennediate in CEC and exchangeable Na. Further, the soils on lowland under influence of the back-waters of the rivers and canals in saucer-shaped physiography are characterized by different shades of grey colour, clayey texture, low organic carbon, alkaline reaction (pH 7.9–10.2) and high EC (2.0–9.6 dS mol), CEC and exchangeable Mg and Na. In lowland soils, argillipedoturbation followed by salinization and sodiurnization of various degrees are operative. Based on the characteristics, the upland soils are classified as Psammentic/Udic Haplustalfs and lowland soils as Typic Haplusterts.