study of individual ecology of salsola tomentosa (moq.) spach at khorasan razavi

salsola tomentosa is a permanent plant belonging to chenopodiaceae family, its type is formed in many areas and in some other areas it is seen sparsely with artemisia species. investigation and determination of ecological needs of the species s. tomentosa was begun in 1383 and lasted for 3 years. the aim of the experiment was to recognize the locus of this species growth in razavi khorasan province. in this research, factors such as: topography, pedology, climatic conditions, phonology, morphological characteristics, capability of seed germination, permanency and the mode of reproduction were studied. geological and pedological studies of the stands with the use of the respective maps and field visitation and laboratory results were done. growth chronology and morphological study was done by marking 30 plants in two habitats gonabad and bardskan within a fifteen-day interval. also, plant vegetation was determined by using 3 transects with a length of 10 kms and with a distance of 3 kms away from one another. (in each site ). a plotting of 1*2 was performed over each transect in every 1 km. the study result showed that s. tomentosa adapts itself to arid conditions. this species, due to having lots of hairs in shoots is not grazed in spring, summer and fall. for this reason, it is abundantly seen in the ranges of dry regions. its importance is due to the fact that in winter when there is poor vegetative growth in the arid range regions, seeds and twigs are grazed by animals. and for this reason it is of great value to the ranchers. also bioenvironmental factors and control of soil erosion. for this reason the development of species in arid areas is of great importance. this species grows in semi deep and deep soils with sandy and sandy loam textures with a large amount of gypsum in soil.