Investigation of soil index affecting on desertification in alluvial fans using AHP-VIKOR technique, case study: south of Rude-Shoor watershed area

Investigation of desertification trend needs an understanding of phenomena creating changes alone or action and reaction together in the manner that these changes end up in land degradation and desertification. In investigating pedological criterion affecting on land degradation in alluvial fans, first, maps of slope classes, land use and geology were created, then a map of units was founded by overlaying and crossing these maps and grid layer created by extension of ET GeoWizards in ArcGIS 10.3 software. In this research, three indices of erodibility, salinity and permeability of soil were considered, finally each was shown in the shape of classified map. Then, weights of criteria and consistency ratio were calculated by AHP method. In this research, VIKOR method was used to prioritize the options. Results showed that the VIKOR index obtained from AHP-VIKOR technique alters from 0.002 to 1.000. Units of V1 and V10 with VIKOR indices of 1.000 and 0.002 have a maximum and minimum of desertification potential, respectively. The alluvial fans in research area were classified in two classes of I and IV from the view point of pedological criterion affecting on desertification using AHP-VIKOR technique, in the manner that 74.18 % of the area is in the low desertification potential, and 25.82 % is in the very high desertification potential, respectively.