Evaluation of the agricultural development and groundwater use on desertification in Tashk region, Fars province

Arid and semi-arid climates cover a large part of Iran. In this areas، agricultural activities depend on irrigation and groundwater. Extra use of groundwater resources and incorrect irrigation methods has caused salinization and water table draw down and depletion of groundwater resources. The objective of this research is assessment of desertification using water and soil degradation indices due to agriculture activities in Tashk region of Fars province. After sampling and evaluation of indices، randomized statistical classification applied and then geometrical averages of points using Arc GIS software are calculated. Finally with combination of different data layers، the final map of desertification intensity of the study area is prepared. Results show that numerical value of current desertification status based on the twp indices is 2. 61 that can be grouped in to high intensity of desertification category. Between two indices، water index with an average weight of 2. 9 has more effects on desertification than agricultural development with an average weight of 2. 4 in this area.