Soil Fertility Evaluation of Ardabil Plain for Wheat and Potato Based on some Soil Chemical Properties by AHP and GIS Techniques

In modern agriculture، the preparation of soil fertility map seems to be necessary to plan for appropriate using of fertilizers for crops. This study was conducted to prepare a distinct map for evaluating soil fertility according to soil chemical properties in 136 soil samples of Ardabil plain in Ardabil province. To achieve this purpose، the available K and P، total N، EC، pH and organic matter of soil were mapped using geostatistical Kriging estimator into Geographic Information System (GIS) by ArcGIS9. 3 software. The Analytical Hierarchy Process (AHP) was used for weighting soil fertility factors as the input data. Then a membership functions was defined for each factor by factorial scoring and the map of soil fertility was prepared and classified for wheat and potato by using AHP technique into GIS program. The results showed that 74. 84، 3. 59، 19. 3 and 2. 32 percentage of lands for wheat cropping were classified based on soil fertility into groups of weak، moderate and suitable، respectively while for potato it was 24. 88، 27. 57، 7. 19 and 40. 34 percentage، respectively. As a final result، this type of distinct soil fertility map for different crops could assist us to manage the appropriate using of lands and fertilizers.