Department of Soil Science and Agricultural Chemistry, S.V. Agricultural College, Acharya N.G. Ranga Agricultural University, Tirupati, 517502, Andhra Pradesh. venkata_naidu8888@yahoo.com
Mineralogy of clay fractions and characteristics of soils developed from granite-gneiss parent material of Yerpedu Mandal in Chittoor district of Andhra Pradesh were studied. The clay fraction of these soils exhibited the characteristic peaks of smectite, mica and kaolinite. Semi-quantification of clay fractions based on relative areas under corresponding peaks indicated that the pedon 1 is dominated by quartz followed by mica, kaolinite and feldspars. Pedons 2, 3 and 6 are dominated by kaolinite whereas pedon 5 characterised by dominance of mica. Further, smectite is the only dominant mineral in pedons 4 and 7.
Clay mineralogy, Yerpedu mandal, smectite, kaolinite, mica, quartz, feldspar
