Effects of different parent material on the mineral characteristics of soils in the arid region of Turkey.

Physical, chemical and mineralogical characteristics of seven soils developed on four different parent materials such as basalt, limestone, marine and alluvium were studied to determine the effect of parent material on the soil characteristics in the arid and semiarid regions in the Southeast Anatolia Region of Turkey. Parent material have affected the morphology and chemistry of the soils. Carbonate contents of the soils are changing between 14.1 and 42.6%. The high carbonate contents of the soils, developed on the basalt rocks, might be attributed to eolian additions from calcareous soils. The red colour of basaltic soils might be associated with the Fe2O3 content of the parent material. Available Fe2O3 content of the basaltic soils was relatively higher than other soils and measured between 0.56 and 2.05%. Available Fe2O3 content of the soils on the marine was very low and changed between 0.26 and 0.37%. Total Fe2O3 content of the basaltic soils was higher than other soils and changed between 4.36 and 6.70%. The total Al2O3 content of the basaltic soils was obtained relatively higher than other soils and changed between 4.92 and 8.72%. The high Al2O3 and Fe2O3 contents of the basaltic soils may be associated with the weathering of basalt rocks. Also analysis of the basaltic rock samples has showed similar mineralogical composition. X-Ray diffraction analysis data showed that smectite was the dominant clay mineral in all the soils. Palygorskite was the second most abundant mineral after smectite. Moreover, some mineralogical properties reflected the traces of climatic changed during the Holocene. The leaching factor were determined as >1 in the Profile PL2 and as < 1 in the Profiles PL1, PL3, PL4, PL5; PL6 and PL7. The low leaching factor (< 1) may be attributed to weathering of parent material. The soils were classified according to Soil Taxonomy as Aridisol, Entisol, Vertisol and Inceptisol.