the effect of land use changes on mineralogy and micro-morphology properties of clay soil on lordegan county – in chaharmahal and bakhtiari province

this study was conducted to investigate the type and origin of clay minerals via several profiles in lordegan hilly lands. the profiles were located in two kinds of land uses including forest and dry farm at different slope positions as sampling sites. the soil saples were collected from two depths of soil horizons to indicate cec, soil texture, oc%, calcium carbonate equivalent, x-ray diffraction and micro-morphological study via undistributed soil sampling. the results illustrated that the dominating clay minerals are illite ،smectite, chlorite and chlorite-smectite as mixed minerals. according to the result, the origin of minerals in both land uses and different slope positions is inheritance from parent material. these minerals are mostly apparent in lower positions of the slope especially rain feed. thin sections investigation of some horizons in the both land use in different slope positions showed that there was no difference regarding the kind of soil voids and c/f ratio between two sampling sites.(including land use and slope positions). complex packing voids, vugh and planar voids were the most dominant voids of these profiles. the observed b-fabric in all horizons was crystallitic and soil structure in back slop was subangular blocky. in all horizons of rain feed land use except for shoulder and back slop, clay films and calcite coatings were observed.