Investigation of pedological criterion on land degradation in quaternary rock units (case study: Rude-Shoor watershed area)


1 Assistant professor, International Research Center for living with Desert, University of Tehran, Iran

2 MSc. of Watershed Management , Faculty of Natural Resources, University of Tehran, Iran

3 MSc Student in Desert Area Management, Faculty of Natural Resources, University of Tehran, Iran

4 Department of Geology, Faculty of Science, Islamic Azad University, North Tehran Branch, Tehran, Iran


To investigate pedological criterion on land degradation in Quaternary rock units, at first, a part of the shoor watershed area was selected. After distinguishing target area, slope classes, land use and geology maps were created, then map of units were founded by overlaying and crossing these maps. In this research three indices of erodibility, salinity and permeability of soils were considered that finally each of them was shown in the shape of classified map. Then by overlaying and crossing of these maps, a new map was created that is an expression of research area zonation from the viewpoint of indices that formerly, were explained. As determining and distinguishing of desertification intensity of potential of created units from crossing of indices was not possible with using of pure mathematical or statistical relations, so were exploited principles and concepts of fuzzy logic and statistics to achieve to main result. We used functions of fuzzy algebraic sum, fuzzy algebraic product and fuzzy gamma after determining weight or value of fuzzy gamma after determining weight or value of factors. Obtained results from a comparison of gained maps from different operators with an evidence map as control area including maximum of desertification intensity, were measured in research area, to prove fuzzy function usefulness for zoning of desertification intensity or potential in research area and similar area with function of 0.8 from fuzzy gamma model (gamma = 0.8 ). Finally by overlaying the desertification potential zonation map with geological map, kinds of soil zones were characterized on the base of their desertification effect. This research determined three classes of desertification qualitative potential (very high 23/08%, high 56/88% and moderate 20/04%).