the role of land use changes on desertification in imam khomeini airport region-iran from 1956 to 2003

the kind of land use and intensity of its change is considered as important desertification indices in different models. land use change is one of the main anthropogenic factors in the desertification. the current research was carried out around imam khomeini airport, with an area of 32000 km2, in order to evaluate mentioned area's land use changes effects during 1955-2003 on desertification. to study the changes, aerial photos of 1955 (1:55000) and 2003 (1:40000), in addition to irs (pan and liss iii) and etm images of 2003 were used. boundaries of different land uses were determined based on aerial photos and satellite images. in the next stage, boundaries were controlled in the field. five kinds of land uses including agricultural land, abandoned agricultural lands, rangelands, industrial regions and complex, were distinguished in the study area. the extent of land uses areas, except to complex, has been changed during the 48 years. rangeland has least change (1.5%), while 14% of agricultural areas have been changed into abandoned and industrial areas. this research showed that biomass has been decreased to 24355.6 ton during the last 48 years. this leads to the decrease of organic matter and decline of soil quality, which in turn causes a 32.9% increase of area regions with severe and very severe desertification intensities.