Document Type : Research Paper
Authors
1 Research Instructor, Research Center for Agriculture and Natural Resources, West Azarbaijan province, Urmia, Iran
2 Assistant Professor, Range Research Division, Research Institute of forests and Rangelands, Tehran, Iran
3 M.Sc. of Range Management, Research Center for Agriculture and Natural Resources, Yazd, Iran
4 M.Sc.Student of Range Management, Faculty of Natural Resources, Agriculture & Natural Resources University of Sari, Sari, Iran
5 Ph.D. Student of Combat Desertification, Hormozgan University, Hormozgan, Iran
Abstract
In this research, Astragalus effusus was considered for autecological study in West Azarbaijan’s catchments. This palatable range species belongs to Papilionaceae. In this study, the ecological characteristics (climatic, topographic, edaphic), distribution in the catchments, phenology, root system, and preference value of Astragalus effuses were investigated. The main part of the study was conducted in study sites of Poldasht (at the elevation of 900 m asl and mean annual rainfall of 120 mm), Shahidan valley (at the elevation of 1700 m asl and mean annual rainfall of 500 mm) and Salmas (at the elevation of 2000 m asl and mean annual rainfall of 338 mm) at different time intervals. The results showed that Astragalus effusus grew in all West Azarbaijan’s catchments from an elevation of approximately 800 to 3575 meters above sea level in all geographic aspects. It grew best on medium-textured soils, from sandy loams to clay loams. Some of the main companion species of Astragalus effusus were Onobrychis cornuta, Bromus tomentellus, Achillea millefolium, and Stachys schetschegleevii. In Salmas study site, the time of initial growth, vegetative growth, flowering, seed ripening and seed dispersion of this species were late March, late April, mid May, mid June and late July, respectively. Astragalus effusus was a tap-rooted species and its roots penetrated to the depths up to 2 meters in sandy loam soils of Salmas region. The geologic studies indicated that the main habitats of the Astragalus effusus were areas with lithologic characteristics of dark gray limestone and red marly limestone with shale in the upper part. This species had no toxic substances and was proper spring forage for livestock.
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