Department of Soil Science and Agricultural Chemistry, S.V. Agricultural College, Acharya N.G. Ranga Agricultural University, Tirupati, Andhra Pradesh, 517502.
Present address: †Division of Soil Science and Agricultural Chemistry, Indian Agricultural Research Institute, New Delhi, 110012.
The mineralogical and chemical characteristics of soils developed from quartzite and granite-gneiss parent materials of the Sivagiri micro-watershed in Chittoor district of Andhra Pradesh were studied. The clay film invariably exhibited the characteristic peaks of smectite, kaolinite and mica. Semi-quantitative estimates of clay fractions based on relative areas under corresponding peaks indicated that the pedons 1, 2, 3, 5, 6, 7, and 8 are dominated by smectite followed by kaolinite and mica whereas pedons 4 and 9 are dominated by kaolinite followed by considerable amounts of smectite and mica. Feldspar and quartz are present in traces. However, use and management of these soils for agricultural production require an understanding of their clay mineralogy
Clay mineralogy, micro-watershed, smectite, kaolinite, mica, quartz, feldspar
