Document Type : Research Paper
Authors
1
Department of Reclamation of Arid and Mountainous Regions, Natural Resources Faculty, University of Tehran, Karaj, Iran.
2
Desert Research Division, Forests and Rangelands Research Institute, AREEO, Tehran, Iran.
Abstract
Plant species distribution in arid regions is strongly influenced by soil physical and chemical properties. This study investigated two subregions in Qom province, Iran, namely Hoz-e Sultan (HS) and Hosseinabad Mish Mast (HMM), to identify the main edaphic drivers of plant distribution. Soil samples were collected from surface and subsurface layers (0–20 and 20–80 cm). Physical and chemical properties, including soil texture, electrical conductivity (EC), pH, calcium and magnesium (Ca+Mg), sodium (Na), sodium adsorption ratio (SAR), exchangeable sodium percentage (ESP), organic matter (OM), Calcium carbonate equivalent (CCE), and gypsum were measured. The relationships between these properties and species occurrence were analyzed using Pearson correlation and Principal Component Analysis (PCA). In the HS region, PCA revealed that two main components explained 81.36% of the total variance. Component 1 primarily reflected soil sodicity (high loadings for ESP, SAR, Na), while Component 2 represented salinity and organic matter-related variation (high loadings for EC, Ca+Mg, OM). In the HMM area, three components accounted for 87.9% of the variance, comprising soil salinity and cation content (EC, Ca+Mg), sodicity (SAR, ESP, Na), and soil reaction and carbonate content (pH, CCE).The results indicated that in the HS region, Halocnemum strobilaceum and Tamarix passerinoides were dominant under saline and alkaline conditions, while Haloxylon ammodendron and Seidlitzia rosmarinus exhibited wider adaptability in soils with lower salinity and alkalinity. In the HMM area, Haloxylon persicum was the dominant species in sandy, alkaline soils with moderate to high salinity, demonstrating robust adaptation to desert conditions. Additionally, Alhagi camelon and Cornulaca monacantha were identified as species resistant to salinity and alkalinity in this area. These findings underscore the critical role of soil chemical and physical properties in shaping plant distribution and diversity in arid environments. The results can also provide valuable insights for desertification control projects.
Keywords
)