investigating the effects of number and frequency of incisions on production and survival of astragalus keyserlingii

tragacanth gum is one of the most important medicinal and industrial productsof rangelands and is obtained from the incision of gum tragacanth-producing astragalusincluding astragalus keyserlingii. the conservation of astragalus species in rangelandshas a special place in terms of economic profit and soil conservation. the increase in priceof gum tragacanth in recent years and more attention of beneficiaries to the extraction ofthis material from the existing astragalus in the rangelands could cause the destruction ofastragalus species producing gum tragacanth. this research was aimed to provide ascientific method for the exploitation of gum tragacanth as well as the conservation thisspecies. the study was conducted in tiran, isfahan province, iran using a split plot designin the layout of a completely randomized blocks design with three replications. eachreplication included 30 shrubs that were exploited for the first time. treatments includedthe number of incisions and harvests. the traits were gum tragacanths production, the plantmortality percent and canopy cover percent. according to the obtained results, the numberof harvests had a negative effect on canopy cover. this result clearly shows that this plantis resistant against the incision since it has maximum canopy cover percent even underthree-time incision in the sixth year. the highest mortality equivalent to 53% was recordedin six-time harvest and the highest production was obtained for six-time harvest a year withan average value of 156.9 g per 30 shrubs, having no significant difference with the fourtime one a year. overall, two scars and four-time harvest could be recommended for theexploitation of a. keyserlingii.key