Characterization, Classification and Evaluation of Soils in Semi-arid Ecosystem of Vedurukuppam Mandal in Chittoor District of Andhra Pradesh

Abstract

Seven typical pedons representing major land forms namely plains and uplands originated from granitegneiss parent material in semi-arid eco-system of Vedurukuppam mandal under varying land uses in Chittoor district of Andhra Pradesh were studied for their morphological characteristics, physical and chemical properties and soil genesis. These soils were slightly acidic to slightly alkaline (pH 6.12 to 7.83) in reaction, non-saline (0.06 to 0.40 dS m-1), shallow to very deep and had isohyperthermic temperature and ustic soil moisture regime. Texture, organic carbon, cation exchange capacity and base saturation of the soils were found to vary from sandy loam to clay loam, 0.9 to 7.3 g kg-1, 15.35 to 32.53 cmol(p+)kg-1 soil and 70.96–89.52 per cent, respectively. Soils were low to medium in available N (87.80 to 188.16 mg kg-1), high in available P2O5 (14.36 to 36.64 mg kg-1) and medium to high in available K2O (61.15 to 240.36 mg kg-1) and sufficient in available sulphur (17.50 to 72.50 mg kg-1). The DTPA extractable Zn was found to be deficient to sufficient (0.52 to 1.54 mg kg-1) whereas DTPA extractable Fe (6.32 to 24.02 mg kg-1), Cu (0.60 to 2.68 mg kg-1) and Mn (4.40 to15.86 mg kg-1) were sufficient. The pedon 7 grouped under Entisols due to absence of sub-surface diagnostic horizon and was classified as Lithic Ustorthents whereas pedons 1, 2 and 4 were grouped under Inceptisols due to presence of cambic (Bw) sub- surface diagnostic horizon and classified as Typic Haplustepts, Lithic Haplustepts and Typic Haplustepts, respectively. Pedons 3 and 6 and 5 were grouped under Alfisols due to the presence of argillic (Bt) sub-surface diagnostic horizon and classified as Typic Haplustalfs and Typic Rhodustlafs. All soils of the study area fall in cultivable land under land capability sub-classes viz., IIIs, IIIw and IVes. On the basis of major soil constraints and potentials, suitable land use plan for Vedurukuppam mandal was suggested.