Investigation of soil characteristics and physiographic factors affecting the establishment of the exclusive species of Platychaete aucheri (Boiss.) Boiss. In Hormozgan province

Platychaete aucheri is one of the exclusive and important rangeland species in the south of the country that has an important role in animal nutrition. In this study, using a generalized increase model, the pattern of response of this species to the slope of soil and topographic factors in its habitats in the province Hormozgan was identified and for this purpose, three regions of Bastak, Sirmand and Kuh-e-Geno, which were the main habitats of the species, were selected and vegetation information and habitat factors of the species were collected. The results showed that all soil measurement parameters except acidity were significantly different at 5% level. The highest electrical conductivity, the percentage of soil saturation and silt was in Bastak region, the highest amount of soil lime and sand was in Sirmand region and the highest percentage of organic carbon, nitrogen and soil clay was in Geno mountain region. Soil texture in Bastak was loam and sandyloam, in Sirmand was sandyloam and in Geno region was sandyclayloam. The application of a generalized collective model for each of the environmental variables showed that the response of Platychaete aucheri to soil sand percentage, soil silt percentage, soil salinity, soil lime percentage, slope and altitude was significant. With increasing sand percentage and soil lime percentage, the species response is increasing and the presence of species is increasing. With increasing soil silt percentage and with increasing slope percentage, species response is decreasing and species presence is less. By increasing the electrical conductivity of the soil, up to 25 species responses are increased, and after that, with the increase of electrical conductivity of the soil, the presence of the species decreases. With increasing the percentage of soil saturated moisture to 20%, the species response is increasing and since then with increasing the percentage of soil saturated moisture to 35%, the presence of the species has decreased and again with increasing the percentage of soil saturated moisture, the presence and growth of the species has increased. With increasing altitude up to 400 meters, the species response is increasing and since then with increasing altitude to 650 meters, the presence of the species has decreased and again with increasing altitude, the presence and growth of the species has increased.