Assessment of relationship between vegetation and salt soil in Qom province

In this research relationship between vegetation and salt soil in Qom province was studied. The study area situated in central Iranian which is about 14631 km2 with Salt Lake. In this study, first considered region condition including the geographical position, geological history, pedology and climate. The aim of this study was assessment of plant communities of area and their relationship with soil. Primarily the vegetation types were distinguished at the field with physiognomic-floristic-ecologic method. The species data were gathered with stratifield random sampling method using the 10m by 10m quadrats recording the species covers, litter, bare soil, stone and gravel cover in the quadrat. In this study were considered 11 soil factors in 48 types of rangeland. Using cluster analysis was separated 13 plant communities in the region. To determine the effect of environmental factors on the establishment of vegetation was used CCA ordination method using software CANOCO. Ordination results showed that environmental factors such as electrical conductivity (EC), lime, sodium (Na), potassium (K) and calcium(Ca), are studied the most important role in the establishment and expansion of areas plant communities. Also plants of Chenopodiceae family compared with plants of Poaceae family have efficient mechanisms of salt tolerance. In salt lands gradual change of soil moisture, zoning of different species and vegetation types to come in parallel strips. Thus topography of the ground, although small, are the main factors of soil chemical and physical changes, and naturally caused the formation of specific habitat for various plant species.