Division of Soil Science and Agricultural Chemistry, Indian Agricultural Research Institute, New Delhi
*Present address: Department of Soils, Punjab Agricultural University, Ludhiana, Punjab
**Present address: All India Soil & Land Use Survey, South Zonal Headquarters, Hyderabad (A. P.)
***Present address: Bidhan Chandra Krishi Viswavidyalaya, Kalyani, West Bengal
The clay mineralogical composition of the surface soils from the different climatic regions of India was studied. Specific area measurements Indicated only broad mineralogical make up of the soil clays. However, these in conjunction with Y-values and physicochemical data yielded better results comparable to X-ray diffraction data.
The soils from (1) humid to sub-humid temperate region with weakly expressed dry season, (2) high rainfall zone with weakly expressed dry season, and (3) low rainfall zone with strongly expressed dry season though predominantly illitic, they were differentiated on the basis of their kaolinite contents into abundant, common and detectably present, respectively. Soils of high rainfall zone with strongly expressed season have preponderance of kaolinite with small amounts of smectites, whereas soils of sub-arid to sub-humid zone with alternating dry and wet seasons have dominance of smectites in their clay fractions.
Clay mineralogy, specifc surface area, Y-values, X-ray diffraction, soils of varied climatic regions
