Abstract

                                In Part of I of the series (1) the distribution of the different soils in the state as a whole and in the various districts and taluks was described. In the second part (2) a fairly detailed description of the black soil of Madras was presented with data as to the mechanical composition, alkalinity, cation exchange properties and the fertility status of two of the important types. In the present paper the red soil of Madras including the red earths, lateritic and laterite soils are dealt with. The broad basis for the revenue classification of soils are colour and texture and all soils with red colour are put into one group irrespective of their mineralogical and chemical composition. However, from a consideration of their properties and composition the red soils can be subdivided into two main categories: (1) the red earth with Kaolinitie clay and (2) the lateritic and laterite soils with a preponderance of hydrous oxide clay. The red soil is the most important soil in Madras in respect of area. It occupies 19 million acres (63% of the total cultivable area) as compared with less than 6 million acres of black soil.

Key words :