Weathering Rates and Some Physico-Chemical Characteristics of Soils Developed on A Calcic Toposequences

Abstract

Soil formations were highly associated with topographic positions which have influence on morphological, mineralogical and weathering process of the soils. Because, topography or relief affects how water and other material are added to and removed from soils. The aim of this study is to carry out a pedological assessment of the soils classified as Regosol, Cambisol and Vertisol by taking into consideration FAO classification system formed on different topographic position and the same parent rocks (limestone-marl). In addition the second aim of this research is to answer the question about the difference in classification resulting from pedogenic processes or from other factors by determining the degree of weathering soils using geochemical data. For this aim, after macro-morphological identifications were completed for three representative soil pedons, the soil samples were then collected from the horizons to investigate the analytical characteristics such as mineralogical, geochemical and physio-chemical properties. The study will also take into account other features such as the pedogenic evolution of soils using weathering indices such as CIA, CIW, Base/R2O3, WIP and PIA. According to results, CIA, CIW, PIA and WIT index values of all soils varied between 66.75-73.87, 73.48 - 81.79, 57.60-68.49, respectively. In addition it was found that the bases/R2O3 values of most of the soils were below 1.0. The results clearly showed that topographic condition strongly affects on soil physic-chemical, mineralogical and morphological properties either directly or indirectly in the local region. This case was also explained with chemical weathering indices in this study.