effects of land use changes on some physiochemical properties of soil of saman region (chaharmahal va bakhtiari province- iran)

soil organic carbon has been the most important soil quality measurement factors and has intense relation with soil physical, chemical and biological characteristics. organic matter and its components are important factors of soil aggregates constitution and stability and play significant role in its structure.so, this research has been done for achieving this purpose. this area is arounding saman _ one of the charmahalobakhtiari counties in distance 20_30 km northeast. in this study, from 127 point in 3 land uses of fruit garden, degraded range, and dry farming, soil sampling of surface depth 0_30 cm was done. the soil samples were analyzed chemically and physically. also ,soil organic carbon supply , mean weight diameter, particle organic carbon in macro and micro soil aggregates and total particle organic carbon were measured. for considering lands username type effect on soil characteristics and organic carbon physical distribution in case study area, variance analysis by sas software and comparing averages by dancon method were done. comparing soil characteristics in 3 land uses of garden, degraded range and dry farming showed that land uses changed on ph, lime and soil bulk density have not been affect significantly but have affected on total soil organic carbon, soil nitrogen, ec, soil organic carbon supply, mean weight diameter, particle organic carbon in macro and micro soil aggregates and total particle organic carbon. in garden land use, most total organic carbon rates, total nitrogen rate, soil organic carbon supply, mean weight diameter, particle organic carbon in macro and micro soil aggregates and total particle organic carbon has been observed. increasing mwd in garden land use is related to high rate of organic material in this soil.