Determination of soil fertility using multi-criteria decision in Tarbor-Darian plain, Fars province

Soil fertility describes the ability of soil to create the conditions for sustainable growth, optimum plant. The elements in the soil productive effects on soil structure, soil texture, water retention in the soil, water infiltration in the soil. On the other hand, with respect to the elements in the soil, the manure is used for different plants. One of the major goals of modern agriculture, efficient use of fertilizers. The use of chemical fertilizers, regardless of the elements in the soil, causing the balance of nutrients, loss of energy and environmental problems. So to determine the fertility of the soil due to fertilizer and plant species to determine the next Managing agricultural land is important. The parameters such as potassium, phosphorus, organic matter, copper, manganese, zinc and iron were studied. For this purpose, the data of 38 soil samples were used. Average Inverse Distance method (IDW) for mapping each element was used in GIS. In order to homogenize the data to produce a map of soil fertility phase method was used. Fuzzy membership functions were prepared using standard soil fertility. Finally, in order to ensure a different level of soil fertility maps sorted by weighted average (OWA) was used. The final results of soil fertility study area using OWA showed that risk appetite (no trade-off) is most problematic area in terms of soil fertility. So that the results showed that the class 4 and 5 areas with fertile soil and good average in the study area show a greater area than the rest of their class. However, with increasing levels of reliability and reduce the risk areas was more difficult in terms of soil fertility. So that more area in the classroom is one that has a poor soil fertility.