effect of topography and soil properties on distribution of ferula pseudalliacea (bitter asafetida) in yazd province, iran

Ferula pseudalliacea (bitter asafetida) is an endemic medicinal plant grown in the center of iran, which is used in pharmaceutical industries. there is less report about its habitat characteristics and distribution in iran. so, this research was conducted to study the effects of topography and soil properties on distribution of this species in yazd province, iran in 2016 and 2017. two habitats (chenarnaz and borooieh) were selected and data were collected for vegetation cover and soil parameter using random systematic methods. all data were analyzed in spss software. the results indicated that this plant often grows in mountainous regions with calcareous formation. its phenological activities are extremely under the effect of climate conditions. this species grows in all aspects and slopes higher than 25%. in chenarnaz, the highest canopy covers was in north aspect (3.13%) and the lowest canopy covers was obtained in south aspect (1.65%). similarly, the highest amount of canopy covers was observed in north aspect (2.55%) and the lowest one was in south aspect (1.65%) in borooieh. 2400-2500 m altitude had the highest amount in two habitats, so that the amounts were obtained in chenarnaz 3.42% and in borooieh 2.55%. there were significant differences for many parameters between two habitats. the higher mean values of canopy cover percent, density, plant area, collar diameter, thousand seed weight and soil parameter as saturated moisture, silt, ph and organic matter were obtained in chenarnaz and the highest sand percent and ec were obtained in borooieh habitat. the results showed that this species grows in soils with lime amount between 55.92% to 58.27% and sandy loam texture, acidity of 8.09 to 8.23 and organic matters of 1.20% to 1.97%. the results of this study can be noticed for proper range management, conservation and development of this valuable species in such conditions.