The Effect of Land use Change on Some Physical Chemical and Mineralogical Properties of Soils of Karezan Region, Ilam Province

Changes in land uses are of the human interventions influencing ecosystem processes. In this study, some soil properties and clay mineralogy have been studied in three land uses including a combination of oak forest and dry farming, dry farming and 20-years-old abandoned dry farming in Karezan region. Soil samples were taken from control profiles of each land use and the soils were classified based on key soil taxonomy 2014. The results of soil properties showed that the highest ρb is 1.59 gr/cm3 in surface horizon belonged to 20 year- old abandoned farming. The lowest soil pH in surface horizon belonged to combination of oak forest and dry farming usage with amount of 7.28 and the highest belonged to 20 year- old abandoned farming usage with amount of 7.61. OM in combination of oak forests and dry farming usage was 1.15 % which was higher than other usages. The highest percentage of lime in surface horizon belonged to 20 year- old abandoned dry farming usage .The highest CEC in surface horizon belonged to a combination of oak forest and dry farming usage with amount of 24.56 cmol+/kg. In all land uses, all measured metal oxides except calcium oxides were decreased from surface to the depth of soil. Also, except calcium and magnesium oxides, the rest of metal oxides had a decreasing trend from the top of slope downwards. Clay mineralogy by X-ray indicated that Vermiculite, Kaolinite, Illite and Chlorite composed the main parts of clay minerals and different usages did not affect the type of identified clay minerals.