effect of land use changes on physical fractionation properties of organic matter, clay dispersion and aggregate stability in some khuzestan soils province

this research was conducted to study the effect of land use change on some physical fractionation component of organic matter and some of its quality factors. therefore, two uncultivated and cultivated (such as rotational cropping and sugarcane) were selected in khuzestan province. disturbed and undisturbed soils were sampled from 0-30 and 30-60 cm depths. total n, oc, dispersible clay (dc), aggregate stability and organic matter differentiation were comprised as factorial in randomized blocks. the results showed that total carbon content was increased from 3.57 g kg-1 for uncultivated to 10.5 and 10.65% for sugarcane and rotation cropping system, respectively. maximum aggregate stability was belonging to sugarcane and minimum was for uncultivated land use. due to land use changes, dispersible clay content was reduced from 44 in uncultivated land to 33 and 38% under sugarcane and rotation cropping system, respectively. organic carbon content and total n was increased with land use change from uncultivated to cultivate but sand component was more sensitive to the land use change as comparison to other component and reacted rapidly. also, organic carbon and nitrogen was more reach in sand particle of organic matter in surface layer. while, the change of land use increased clay fraction of organic matter at first level, this was for sand fraction in second level and third level was belong to silt. this is related to aromatic structure and resistance of this fractionation of organic matter. it was concluded that for soils do not have good quality, best management practices (bmp) and increase organic matter can improve the soil quality and aggregate stability due to make good situation for cultivation.