effect of some soil properties on distribution of eurotia ceratoides and stipa barbata in baghedar, bafgh rangelands

in order to sustainable use of rangelands, it is necessary to recognize water, soil, and vegetation cover and analyze their relationships. physical and chemical properties of soil are effective in distribution of plant species in local area. to determine the effects of some soil properties on species distribution of eurotia ceratoides and stipa barbata in baghedar summer region of bafgh, three types of vegetative plants were identified including artemisia aucheri-eurotia ceratoides, artemisia aucheri-eryngium bungei and artemisia aucheri -stipa barbata. then data of 20 plots were collected for each type in the desert. after drilling 27 soil profiles and providing samples of 0-30 and 30-60 cm from soil depth, ph, ec, caco3, organic carbon, caso4, and gravel parameters and distribution of soil grain were determined in the laboratory. one-way analysis of variance was made using spss software. analysis of variance showed that clay and caco3 in the soil first depth and caco3 and gravel% in the soil second depth have significant differences in three vegetation types. then to determine parameters affecting on separating vegetation types, principal components analysis was performed on 17 variables (16 soil variables and slope percentage) using pc-ord software. results of pca indicated that in the first axis slope%, clay in the second depth and caco3 and sand in the first depth, explain 61% of the variations and for the second axis included sand in the second depth and electrical conductivity and organic matter in the first depth, explain 38% of the variations. the results of the research show that eurotia ceratoides was more dispersion in areas where the lower and upper layers of soil had less clay and caco3 and stipa barbata is seen in lower layers of soil having more clay and more caco3 and less organic carbon and ec in upper soil layers.