AUTECOLOGY O salsola tomentosa.

Investigation on ecological needs o species consistent with ecological condition, together with precise recognition o environmental actors aecting species under study is o great value. Salsola tomentosa is a permanent plant belonging to Chenopodiaceae amily, specially, this plant adapts itsel to arid conditions. This species, due to having lots o hairs in shoots is not grazed in spring, summer and all. or this reason, it is abundantly seen in the ranges o dry regions. Its importance is due to the act that in winter when there is poor vegetative growth in the arid range regions, seeds and twigs are grazed by animals. And or this reason it is o great value to the ranchers. Also, bioenvironmental actors and control o soil erosion. or this reason the development o species in arid areas is o great importance. Investigation and determination o ecological needs o the species Salsola tomentosa was begun in 1383 and lasted or 3 years. The aim o the experiment was to recognize the locus o this species growth in Khorasan province. In this research, actors suchas: topography, pedology, climatic conditions, phenology, morphological characteristics, capability o seed germination, permanency and the mode o reproduction were studied. Geological and pedological studies o the stands with the use o the respective maps and ield visitation and laboratory results were done. Growth chronology and morphological study was done by marking 30 plants in three habitats within a iteen-day interval. Also, plant vegetation was determined by using 3 transects with a length o 10 kms and with a distance o 3 kms away rom one another. ( in each site ). A plotting o 12 was perormed over each transect in every 1 km. Results show that this species is seen in all slope directions and in the altitude range rom 330 to 1550 meters rom sea level. The habitats o this species lie in a temperature range o 15-17.5 °C with a precipitation between 100-300 millimeters in arid climates.This species grows in light semideep and deep soils with sandy and sandy loam textures, pH =7.8 – 8.2 and EC=0.76-9.5 ds/m with a large amount o gypsum in soil. The vegetative growth o this species begins rom mid March and enters lowering stage. ruit ormation occurs rom September to November and ater that the ruits begin to all. Its type is ormed in many areas and in some other areas it is seen sparsely with Artemisia species. Its main companion species are: peganum harmala, Halothamnus glaucus, Haloxylon persicum, Scariola orientalis and Salsola sp. The average canopy was % 5.3, requency % 68.8, and the density o 7277 in hectar was determined in study sites. Its root penetrates straight into the soil and its depth is up to 1 meter, with a ew lateral roots in soil. Natural regeneration o the plant is done by seed and ater harvesting these seeds have a very high viability. Keywords: Salsola tomentosa, Autecology, Phenology, Khorasan