Relationship between soil physico -chemical attributes and plant communities (Case Study: Mighan Desert in Arak)

The main objective of the present study was finding spatial relationship model of the plant species composition to physico-chemical soil variability, in north-west of Mighan Desert in Arak. According to the condition of the studied habitats, the study was based on a survey of three identified vegetation types. Sampling method for vegetation study was randomized systematic. Quadrate size was determined for each vegetation type using minimal area method. Soils sample were taken from 0-20 and 20-100 cm depths. The measured soil factors included, EC, organic matter, texture, lime, gypsum, available moisture, pH, and soluble ions (Ca2+, Mg2+, Na+, Co32-, H-Co3, Cl-, So42). The classification of vegetation was analyzed by TWINSPAN and DCA methods. To determine the most edaphically effective factors in distribution of vegetation, PCA and CCA were applied. Three main vegetation groups were identified by TWINSPAN analysis and DCA. The result indicated that soil salinity, soil texture, lime, and soluble ions (Mg2+, So42) played the main role in the distribution of plant species.