Analysis of the role of plant species located on marl formations in controlling erosion (Case study: Varamin County)

- In region according to stratigraphic information obtained from combination of the stratigraphic column existing in geological maps at a scale of 1: 250,000 and sometimes 1: 100000 of sheet Varamin, Tehran, Damavand, and Semnan, and field survey, it was found that geologically in the Precambrian, Paleozoic, and Mesozoic (except Cretaceous) periods, there was a general gap in the region. All marl formations and units which specifically include three units of shale, gypsum marl, sandstone, gypsum marl unit, and brown and red marl unit with interbeded sandstone belonging to the Cenozoic period have been distributed in the northeast, east, south and southwest. From the location of marl distribution, 29 samples of marl soil were chemically and physically tested and the results did not show a significant difference because evaporative sediments were distributed in most areas. Due to solubility of salt and also rarely gypsum and lime and their capillary properties, density of vegetation was very low and the dominant vegetation type was itchy and boneye Alhagi camelorum and Aeluropus lagopoides and the species of Bromus tectorum , Hordeum marinum, Peganum harmala, Artemisia sieberi, Prosopis stephaniana, Phragmites australis, Seidlitlia rosmarinus, Capparis spinosa, Chenopodium murale, Convolvulus arvensis, Tamarix sp, Haloxylon sp, Pteropyrum aucheri, Salsoa arbuscula, Salsola tomentossa as a species with limited distribution in the region. Therefore the erodability of the region showed high erodability. After each collection, the samples were and dried using the necessary and were prepared for storage in herbarium. The collected samples were transferred to the herbarium of the Agricultural and Natural Resources Research Center of Tehran Province and after being pressed and dried they were prepared as herbarium samples and were stored in the herbarium of that center. The prepared herbarium samples were identified using Iranian Flora (Asadi et al., 1990-2011) (15) and Iranika Flora (Rechingr, 1963-2010) as well as professors of botany. soil and plant analysis and identification of physical and chemical factors of soil, some species can be suggested to stabilize marl regions.