Lithological Studies and Types of Soils along Coastal Area of Kanyakumari to Colachel Coastal Belt, South Tamil Nadu, India

Soil types of an area are more important, since soil is the main criteria in agricultural production and in recharge of groundwater. Different types of soils are derived from a wide range of geological formations. Knowledge about type of soils, its extent and occurrence is of primary importance for agricultural planning to maximize production and for groundwater recharge. The soils of the district from Kanyakumari to Colachel coastal belt can be classified into red loams, red lateritic soil and pale reddish. They are derived from lateralization of gneisses. The soils derived from gneisses are mostly brownish. Thickness of soils in mountains is almost negligible, whereas in the valleys they are around 2m thick. The lateritic type of soil occurs in blocks of Rajakkamangalam. The mixed type of red and alluvial soil occurs in Agastheeswaram block. The coastal sand occurs in the western side of the district. The coastal alluvium sand is of high fertility. Generally, the soils are highly acidic in the coastal area. This is mainly due to heavy rainfall and heavy leaching of basic rock in hilly areas.