Study of Relationship Between Roads Network Development and Agricultural Land Conversion in Iran NorthWest

Road network (RN) can affect patterns and distribution of land uses and covers. Road network expansion has both direct and indirect impacts on land uses and covers changes. Agricultural land conversions (ALCs) are especially known as one of the main important types of land use changes. The purpose of this paper, in addition to estimation of the direct impact of RN expansion on ALCs, is to evaluate the ALCs relative to road network location. The study area is Qazvin province in the North West of Iran. To estimate the amount and the location of ALCs a couple of Landsat imageries for 1990 and 2010 were used. Also, to evaluate the relationships between ALCs and RN at first agricultural lands, based on their distance from RN, were categorized into three groups namely a. Less than 2(Km), b. Between 2(Km) to 4(Km) and c. More than 4(Km) to 6(Km). Then, the area of agricultural lands that changed from 1990 to 2010 were estimated for these groups. Finally, the differences amongst these three categories were evaluated. The main results of this study showed, a) 44,845 ha (3%) of the agricultural areas during 1990-2010 were changed to non-agricultural lands; b) 10,243 ha of these lands were converted to Urban and Other Infrastructures; c) the suburban RN has been mainly developed within agricultural lands, especially, within irrigated and orchard lands. In addition, d) ALCs among the closer lands to the roads have been significantly higher than lands which have been away from the RN.