Using ordered weight averaging (OWA) for multicriteria soil fertility evaluation by GIS (case study: southeastern Iran)

Abstract. The Multicriteria Decision Analysis (MCDA) and Geographical Information Systems (GIS) are used to provide accurate information on Pedogenic processes and facilitate the work of decision makers. So, MCDA and GIS, can provide a wide range of decision strategies or scenarios in some procedures. One of the popular algorithm of multicriteria analysis is Ordered Weighted Averaging (OWA). The OWA procedure depends on some parameters, which can be specified by means of fuzzy. The aim of this study is to take the advantage of the incorporation of fuzzy into GIS-based soil fertility analysis by OWA in west Shiraz, Fars province, Iran. For the determination of soil fertility maps, OWA parameters such as potassium (K), phosphor (P), copper (Cu), iron (Fe), manganese (Mn), organic carbon (OC) and zinc (Zn) were used. After generated interpolation maps with Inverse Distance Weighted (IDW), fuzzy maps for each parameter were generated by the membership functions. Finally, with OWA six maps for fertility with different risk level were made. The results show that with decreasing risk (no trade-off), almost all of the parts of the study area were not suitable for soil fertility. While increasing risk, more area was suitable in terms of soil fertility in the study area. So using OWA can generate many maps with different risk levels that lead to different management due to the different financial conditions of farmers.