پهنه بندي اقليم كشاورزي با روش يونسكو و شاخص خشكي تعديل شده در بخشي از استانهاي آذربايجان شرقي و اردبيل

Agro-Climate Zoning (ACZ) through UNESCO Approach and Modified Aridity Index in Some Parts of East Azerbaijan and Ardabil Provinces

Most agricultural lands in Iran, being located in arid and semiarid areas, are characterized by considerable weather variability, as well as major abiotic stresses, in particular drought and cold. The intensification of crop production in these areas needs to take into consideration the agroclimatical diversity, and adapt cropping and land use patterns to the opportunities and constraints of each Agro-Climatical Zone (ACZ). UNESCO approach (1979) is one of the methods used in ACZ mapping. Moisture regime, winter type and summer type are the main parameters in this approach. In the present study mean long term climatic data were modeled through SRTM 90m DEM in GIS software for delineation of ACZ units. A comparison of the UNESCO ACZ units with landuse units derived from the newest Landsat imagery in the studied area and an improvement of this correspondence through the modified aridity indices is the main goal of the present study.In UNESCO approach, areas with aridity indices lower than 0.5 are classified as semi-arid, arid and ultra-arid zones, not fit for agricultural uses. However in arid and semi-arid area of northwest Iran the rainfed and irrigated agriculture are mainly concentrated on the areas with lower aridity indices than 0.5 (between 0.17 and 0.37). Moreover, based on UNESCO method, areas with aridity index higher than 0.5 are classified as sub-humid, humid and ultra-humid zones, capable of being used in normal agriculture, whereas the results of this study show that areas with aridity indices higher than 0.65 are mostly located on highlands with temperature and LGP (Length of Growing Period) limitations and normally covered by forests.