Ecological Potential Modeling for Agricultural and Rangeland Development Using GIS-based FAHP Approach: A Case Study of Razin Watershed

Determining the environmental capability of optimally using land and preventing the degradation of natural resources arr important steps towards a sustainable development strategy. The present study was conducted in 2014-2017 aiming to assess the ecological capability for agriculture and rangeland of the Razin watershed in Kermanshah province, west of Iran, in seven classes using the Fuzzy Analytic Hierarchy Process (FAHP) and the application of Geographic Information System (GIS). The information layers were initially selected by the research group and those layers that were important were selected according to the research literature, then the final screening of the information layers was performed by fuzzy Delphi method. These layers were including land form units (slope, elevation, aspect), soil information (texture, depth, hydrological groups, erosion, granulating, gravel percentage, evolution, organic carbon content, exchangeable cations, available phosphorus), climate, water, land use, vegetation density, and lithology. FAHP technique was used to calculate the importance coefficients of the criteria and sub-criteria entered into the evaluation model. Weighted layer modeling was performed by ArcMap 9.3 software using the weighted linear composition method in overlay tool. The results showed that water, climate, slope, and soil texture criteria with 0.23, 0.132, 0.118, and 0.88, respectively, were the most important in modeling Razin ecological capability. 1776 environmental units with unique ecological characteristics were identified. This area has ecological potential for agricultural and rangeland use in seven classes. In terms of effective carrying capacity (ECC), all classes except class 2 and 5 were sustainable. Due to the very high accuracy of the FAHP-GIS integrated model in the use of agricultural land suitability, it is recommended to use this model instead of other conventional methods.