Fifty six soil samples from sixteen pedons in two transects representing various physiographic positions along a double toposequence of Cumbum valley of Tamil Nadu were studied for vertical distribution of DTPA extractable iron, manganese, zinc and copper and their relationship with some soil properties. Soil reaction (pH), free calcium carbonate, organic carbon and particle size fractions had strong influence on the distribution pattern of these micronutrients in the profile. The content of micronutrients increased with the increase in organic carbon and decreased with increase in pH and free CaCO3. In general, all these micronutrients decreased with increase in depth but they had no definite correlation with topography. As per the critical limit suggested for Tamil Nadu soils, Iron and Manganese were found to be sufficient in most soils except calcareous and recent alluvial soils. Zinc and copper were deficient uniformly in all soils. Site-specific residual copper accumulation was also found.
DTPA extractable cations, Toposequence, Red and alluvial soils, Critical limit
