Investigating Tragacanth Gum potential production and harvesting based on soil factors in Tiran and Karvan region (Isfahan)

The objective of the present study was to assess the ecological potential of Tragacanth Gum production and harvesting based on soil characteristics of Tiran and Karvan rangelands in Isfahan province. Scariolia orientalis-Astragalus gossypinus, Hordeum fragile-Astragalus gossypinus and Cousinia bachtiarica-Astragalus gossypinus vegetation types with relatively homogenious topography conditions were selected, and four transects with 100 meters distance were esatbished obliquely to the general and the lateral slope of the site in each vegetation type. The produced Tragacanth Gum from studied Astragalus individuals along the transects were measured based on their ages ad harvesting stages. Soil samples from two depths of soil surface were collected from the start and end point of each transect and their physical and chemical characteristics were measured. STAT Plus(2009) and SPSS software were used to analyze the data. According to the results, the potential of gum production in Sc. or-As. go vegetation type was more than the two other vegetation types. Soil depth, organic matter, electrical conductivity and soil potassium content in Sc. or-As. go vegetation type were also higher then the two other types. Tragacanth Gum can be harvested from the utilized species after a two years resting period. The estmiated required time for collecting Tragacanth from the utilized species in Ho. fr-As. go and Co.ba-As.go vegetation types was three years. Soil lime and gypsum content in these two vegetation types were more than Sc. or-As. go vegetation type.