Clay Mineralogy of Some Vertisol Soil Series of Mabarashtra

Five typical and widespread Vertisol soil series developed on basaltlbasaltic alluvium formed under different agro-climatic regions were investigated for their fine and coarse clay mineralogy using X-ray diffraction technique and chemical analysis of the soil clays. The smectite was the most dominant phyllosilicate in fine clays (> 90%) with small proportion (< 10%) of kaolinite. The study established the montmorillonite-nontronite series of smectite in Vertisols of Maharashtra. Coarse clay mineral is composed of smectite, kaolinite, quartz, illite, feldspars, chlorites and vermiculites. The wide variation in content of minerals was noticed in coarse clay fraction but not in fine clays of the soils. The weathering mean of fine clays was (8.8 to 9.1) higher than coarse clay fraction (7.5 to 8.1) indicating intermediate intensity of weathering. The molar ratios of fine clays were lower than coarse clays of Vertisols.