Evaluation of active desertification with emphasis on the soil degradation by IMDPA model (case study: Abadeh-Tashk, Fars)

Desertification is one of the most important problems in arid and semiarid lands of the world. Rapid growth of human population and increasing of cultivation cause the degradation of soil and water resources. In the other hand, the reclamation of soil is time consuming and very expensive; therefore, it is necessary to know the destruction factors of soil and its effects on desertification. In order to evaluate soil degradation in agricultural lands of Abade-Tashk, the IMDPA model was used. Four soil indexes: Electrical Conductivity, percent of gravel, depth and texture were applied in this model. For evaluation of soil indexes, randomized network sampling was used and then each index measured according to its effect in the model. The geometrical mean of indexes were calculated using GIS software. Desertification map of each index was prepared and then the current situation of each index obtained. The final map of desertification was prepared by combination of the index maps using mean geometrical method. The results showed that 47% of total area (2212 ha) located in low class of desertification, 43% (2019 ha) in medium class and 10% (467 ha) in high class of desertification.