Abstract

The main objectives of this research were to study the effective factors on vegetation types, the qualitative and quantitative conditions and their relationship to soil characteristics at Ardestan County in the northern part of Isfahan province (Iran). After determining the playa area by aerial photographs and topographical maps, the key area was selected, and vegetation and soil investigations were conducted. Two line intercept with 300 m in length was established, while the plots were located from each other 20 m in distance and their sampling was carried out by random-systematic method. As a result, the various plant factors such as present plant species list, vegetation cover, canopy, litter, bare soil, rock and stone percentages were taken down. In order to study the soil factors, a profile, with 0 to 60 cm depth, excavated in the first, middle and final plots in each transect and after sampling, the soil’s physical, chemical and hydraulical features were measured. For comparison of the soil’s physical and chemical properties, the Duncan’s multiple range test was applied. The results indicated that from the center of the playa towards the motion of the playa, gypsum, calcium, magnesium and silt levels decreased, while organic matter, sand and gravel levels increased. Hence, there is no significant difference among various types, but other factors among these types have significant difference at 5%. In respect to the afore-mentioned results, we can ascertain that in the studied vegetation types, there is a statistical difference at 5 and 1% in factors such as exchange sodium potential (ESP), clay (%), potassium, gypsum and PH, and in other factors such as electrical conductivity, CaCO₃ (%) calcium in ppm, magnesium (PPM), sodium absorption rate (SAR), silt (%), sand (%), elevation in m and slope (%), respectively.

Key words: Dagh Sorkh kavir, soil properties, vegetation type, salinity, Duncan’s multiple-range test.