Geochemical weathering indices are widely used in evaluating the stage of soil development. However, their
compatibility with Soil Taxonomic Classes has not been studied yet. This study was conducted in a hilly region
to illustrate the relations between soil development indices and topographic attributes and Soil Taxonomic Classes.
A grid samplingmethodwas carried out with 100mintervals. Physico-chemical analyses and total elemental
analyses were performed on 184 and 56 soil samples respectively. In addition, eight topographic attributes and
12 common soil development indices were determined. Results showed that among the topographic attributes,
slope gradient and topographicwetness index (TWI) had the highest correlationwith Soil Taxonomic Classes and
development indices.Morphological index (r=0.60) and Feo/Fed ratio (r=0.52) increased with progress in soil
development fromEntisols to Alfisols andMollisols. Despite the significant correlations betweenmost of the geochemical
weathering indices and Soil Taxonomic Classes (Vogt index had the highest correlation coefficient
(r=−0.74)), these indices represented lowerweathering intensity in more developed soils. These relationships
were due to the predominance of more developed soils in lowgradient slopes, where the weathering products of
upper slopes accumulate and their parent materials are carbonatic