Investigation on biological activities for combating desertification ‎in the western shores of Lake Urmia, Northwest Iran

Abstract: Lake Urmia, Northwest Iran, has confronted a drying procedure in recent years with losing 90% of its water body. The authorities concerned about desertification processes and possible dust events throughout the region. In this regard, the Iranian Natural Resources and ‎‎Watershed Management Organization has taken ecological ‎measures to plant vegetation using salt ‎‎cedar (Tamarix ramosissima‎ Ledeb.) shrubs to combat desertification. This study ‎aimed to investigate the vegetation and soil ‎‎characteristics of natural and plantation stands of salt cedar on the ‎western shores of Lake Urmia. To ‎‎this end, 7 transects were randomly selected with 15 ‎shrubs in natural stands, and 7 ‎‎transects were randomly selected with 15 ‎shrubs in the plantation parts along the planting rows. ‎‎Then, vegetative characteristics were examined. Also, soil samples were ‎taken from the ‎vicinity of ‎‎the shrubs. The results indicated that there was no significant ‎difference between the mean diameter at breast height (DBH) of ‎‎salt cedar in natural sites. ‎There was a significant difference between the mean number of sprouts ‎‎per sprout-clumps, ‎mean crown diameter, collar diameter, total height, and also between mean ‎‎crown diameter ‎and freshness of shrubs among different sites (P<0.05‎). It was also found that soil ‎‎variables, such as clay content, organic matter, electrical conductivity (EC), Na+, specific absorption rate (SAR), ‎‎Cl–, SO2– 4‎‎, Na+, K+, and PO2– 4 are the most significant variable parameters between ‎studied sites. As the results shown, the ‎values of EC, SAR, Na+, and Cl– are 6 times higher in the planted stands than in the natural stands of T. ramosissima. Also, the colonization ‎of T. ramosissima in the planted stands is unsuccessful by dramatic drop in the total height and average diameter. Considering the role of soil characteristics in explaining the variance of data and site ‎‎separation, it seems that these indicators can be applied in executive plans as ‎important indicators to identify suitable planting sites for combating desertification.