The Genesis of the Red‐Yellow Podzolic Soils

Mineralogical, chemical, physical, and morphological data are given for 18 profiles of Red‐Yellow Podzolic soils. These soils represent 3 profiles each of 2 sequences, one derived from acid crystalline rocks and the other from sandstones. Six profiles of Reddish Brown Lateritic soils are included for comparison where appropriate. Differences between sequences and within sequences are due either to inherited or to genetic properties, both of which are related to or limited by parent material. All properties studied follow the same kind of distribution with depth. Differences in magnitude reflect inherited differences, whereas the kind of distribution reflects similar genetic differences under uniform environments. Apparent discrepancies in the distribution with depth of clay content, exchange capacity, and associated properties occur as differences in parent materials. Differences in secondary products are also related to differences in parent materials and in turn are related to the observed differences. Suggested mechanisms for the genesis of these soils and their characteristic mottling are presented. The Red‐Yellow Podzolic soils are compared to the Gray‐Brown Podzolic soils in terms of probable genesis.