Abstract

                                To study the depth distribution of different forms of calcium, eight soil profiles were chosen representing eight established soil series in Tamil Nadu at the rate of two series under each of black. red. alluvial and laterite soil groups. The contents of different forms of calcium such as total, exchangeable, water soluble and free calcium carbonate were estimated. Total calcium varied with the types of soil and it was of the following order: black, alluvial, red and laterite soils. In general. it increased with depth. Exchangeable calcium also followed a trend similar to total calcium and it increased with depth of the profile. Water soluble calcium was highest in black soil and least in laterite soil. There was no regular trend of changes in the content of water soluble calcium with depth. Free calcium carbonate was found to be present only in black, red and alluvial soils. Soil topography was observed to influence the calcium carbonate content of the soil.

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