Effect of slope position on selected physical, chemical and mineralogical properties of soil in Chelgerd region, Chaharmahal-va-Bakhtiari

Topography is one of the soil formation factors that has direct and indirect effects on physical and chemical properties, as well as soil formation and development. This study was conducted to investigate the effect of slope position on selected soil characteristics in Chelgerd region of Chaharmahal-va-Bakhtiari, Iran. Three transects were selected on west hill slope and 9 profiles were dug on three slope position, including summit, back slope and foot slope. Soil samples were gathered from each profile for physical and chemical analysis. Soil profiles in the summit and back slope were classified as Inceptisols while soil profiles in the foot slope position were classified as Vertisols. Significant differences between clay, sand and organic matter content in different slope positions were observed. The highest amount of clay and organic matter content were observed in foot slope position and maximum amount of sand was related to back slop position. Mineralogy results showed the presence of different minerals such as smectite, illite and kaolinite in all studied profiles; smectite with more than 70% was the dominant mineral. There was no significant difference between different slope positions in term of mineral composition, but smectite showed a slight increase toward down the slope.