Division of Soil Science and Agricultural Chemistry, Indian Agricultural Research Institute, Delhi
In certain localities of the Kurnool district of Andhra Pradesh, soils on the slope are in catenary sequence and show wide diversity in characteristics. The soil colour gradually changes from dark reddish brown to very dark grey and soil texture from sandy clay loam to clay down the slope pari passu with decrease in the intensity of drainage condition. Chemical composition of the soils shows a typical gradation in topose-quence in that the silica content decreases while aluminium, manganese calcium and magnesium increase. Illite is the dominant clay mineral in the upper and middle profiles of the slope while montmoriilonite is dominant in the profile at the base. Montmoriilonite content increases and kaolinite decreases down the slope. Topography appears to be the dominant factor in the development of the sequence. The similarity of primary minerals in the fine sand fractions indicates resemblance to detrital materials derived from granite-gneiss parent material.
