Advance Centre for Research on Black Soils, University of Agricultural Sciences, Dharwad, Karnataka, 580005.
* Present address: Division of Soil Science and Agricultural Chemistry, Indian Institute of Horticultural Research, Hessaraghatta Lake, Bangalore, Karnataka, 560089.
Forms of iron and their depthwise distribution was studied in jive typical Vertisol series of Karnataka. Fractionation revealed that water soluble, Mn-oxide occluded and organically bound iron decreased, whereas exchangeable, acid soluble, Pb-displaceable, amorphous Fe-oxide occluded and residual Fe increased with depth. The percentage contribution of different fractions to the total Fe was in the following order: Residual > amorphous Feoxide occluded > organically bound > Mn-oxide occluded > Pb-diplaceable > exchangeable > acid soluble > water soluble iron. The amount of iron in labile pools was very low and this could be the reason for the frequent appearance of iron chlorosis in calcareous Vertisols of Karnataka.
Forms of Fe, distribution of Fe, Vertisols
