Mohammad Khosroshahi; Majid Hasani; Shirin Mohammadkhan; Abbas Attarpour; Seyed Aziz Karami; Abolfazl Khalilpour; Ebrahim Farahani; Hamidreza Abbasi
Volume 10, Issue 4 , August 2019, , Pages 409-428
Mohammad Khosroshahi; Majid Hassani; Seyed Aziz Karami
Volume 10, Issue 1 , August 2019, , Pages 40-56
Seyed Jafar Seyed Akhlaghi; Hamid Reza Abbasi; Ammar Rafiee Imam; Mohammad Darvish
Volume 19, Issue 3 , December 2012, , Pages 498-511
Abstract
Desertification is a multifactorial phenomenon and relates to different aspects. Thus, this concept can be studied around multiple axes in natural resources and environment. Nowadays, the rapid growth and huge population in environments and ecological areas are of the most important concerns that have ...
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Desertification is a multifactorial phenomenon and relates to different aspects. Thus, this concept can be studied around multiple axes in natural resources and environment. Nowadays, the rapid growth and huge population in environments and ecological areas are of the most important concerns that have attracted the attention of experts and planners to the concept of desertification or combat desertification .On the one hand, astounding growth of metropolises and unbridled industrial development have led to adverse outcomes for the residents. Moreover, land is a limited resource and the situation will get worse over time in many countries due to the exponential growth of population and extensive use of land and with regard to the fact that only 5 million km2 of the earth has remained for sustainable utilization in future. There are many issues surrounding population supporting capacity based upon the quality of the land in order to maintain the sustainability of resources and environment. The purpose of this article was to estimate population supporting capacity of Tehran and Alborz on the basis of the potential of land units through the method introduced by Central Department of Agriculture of USA. This is the first step to determine the extent of land degradation and detection of man-made desertification. In the current situation, it is obvious that a demographic development of Alborz and Tehran provinces has led to instability in the environment and desertification. Based on the results, classes 1, 4 and 9 of the land quality covered 20.38, 14.93, and 37.44 percent of the surface area, respectively. These three classes could be accounted for 81.9% of population supporting capacity according to the potential of production. Our results showed that lands of the study area were exposed to desertification classified as very high risk (38.55 % of the total area), high risk (25.06 % of the total are), moderate risk (23 % of the total area), and low risk (13% of the total area). Accordingly, it was found that the current population of Tehran province was 5 times higher than the optimal population. This ratio also reaches 4.7 times in high-density areas such as Tehran, Karaj, Shahriar and Robat Karim.
Ebrahim Farahani; Amrali Shahmoradi; Samira Adibi
Volume 19, Issue 1 , June 2012, , Pages 149-158
Abstract
Stipa hohenackeriana Trin & Rupr is a perennial plant of the gramineae family. This species covers a wide range of habitats in Tehran province. The habitat characteristics of this species including topography, climate, vegetation type, soil, associated species, plant phenology and root system were ...
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Stipa hohenackeriana Trin & Rupr is a perennial plant of the gramineae family. This species covers a wide range of habitats in Tehran province. The habitat characteristics of this species including topography, climate, vegetation type, soil, associated species, plant phenology and root system were investigated. The results showed that these habitats were located in altitudes of 880 to 2400 m above sea level. The average rainfall in the habitats was 150 mm to 378 mm. The annual average temperature, annual minimum temperature and annual maximum temperature were 15.5 to 24.4°C, -2 to 12°C and 32 to 42 °C, respectively. This plant was observed in a range of shallow to very deep soils at slopes of more than 0.5 percent. Soil acidity measurement showed levels of 8.1 to of 8.71 and the electrical conductivity of the soil were 0.19 to 0.98 ds/m. In most habitats, this species has emerged as the dominant. Average canopy cover, density and frequency were 8.43%, 9050 plants / ha and 90%, respectively. The ratio of root to shoot weight was 0.226. This plant has a highly branched root system. Phenology of the species in different habitats showed that the growth started from mid-March to mid April. Production stage of pods was in late May. Flowering was from late May to late June. Seed production occured from late May to late July. According to regional climatic conditions, the seeds were matured .From early September to early October the plant was in summer dormancy. This study showed that chemical compounds of crude protein and crude fat were maximum at early growth stage but gradually decreased in the coming stages.
Farhad Azhir; Ali-ashraf Jafari; Mohammad Fayaz
Volume 18, Issue 1 , May 2011, , Pages 139-150
Abstract
In order to determine the best genotype for range improvement in Tehran province, Iran, 19 ecotypes of Agropyron cristatum were sown using randomized complete block design with three replications under irrigation and dry land farming system during 2006- 2007. Data were collected and analyzed for ...
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In order to determine the best genotype for range improvement in Tehran province, Iran, 19 ecotypes of Agropyron cristatum were sown using randomized complete block design with three replications under irrigation and dry land farming system during 2006- 2007. Data were collected and analyzed for dry matter (DM) yield, flowering and pollinating date, plant height and 5 quality traits as: dry matter digestibility (DMD), water soluble carbohydrates (WSC), crude protean (CP), total ash, and acid detergent fiber (ADF).The results showed significant difference at 1% level of confidence for yield and morphological traits while no significant differences were observed for forage quality under two different cultivation conditions. The difference between ecotypes and environment-ecotype interaction effecets were significant for all traits of the species.Ecotypes 208P8 and 4056P4 with average values of 1240 and 1336 Kg/ha had higher forage yield in irrigation condition while in dry land condition, forage yield of ecotypes 619M and 4056P4 with average values of 791 and 901 Kg/ha were maximum.According to the results, ecotypes 1722M (Gorgan), 208P8 (Esfahan)and 4056P4 (Gorgan) with average yield value were identified as the best ones for both yield and quality traits in studied cultivation conditions to be introduced for cultivation in dry land faming in Tehran province.DM yield had positive correlation with plant establishment.WSC had positive and negative correlation with DMD and CP, respectively. The relationship between DMD and ADF was negatively significant.
Ebrahim Farahani; Mohammad Khosroshahi; Majid Hosseni; Seyamak Loghmani
Volume 14, Issue 4 , February 2008, , Pages 490-499
Abstract
Vegitation cover is one of the important environmetal factors which can determine desert areas. In this article, we determine desert areas in Tehran province by GIS. In the study area, dominant plant types and some of main ecological properties of them were assigned. Finally, by available information ...
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Vegitation cover is one of the important environmetal factors which can determine desert areas. In this article, we determine desert areas in Tehran province by GIS. In the study area, dominant plant types and some of main ecological properties of them were assigned. Finally, by available information and public characteristics of every plant type, desert area was separated. In this area, we distinguish 43 plant groups that 7 types of them belong to desert areas. This area is 307647 hectares which is formed 16.43 % of Tehran province.
Ebrahim Farahani; Amrali Shahmoradi; Sadegheh Zarekia; Farhad Azhir
Volume 15, Issue 1 , January 2008, , Pages 86-94
Abstract
Studying the behavior and the way a plant species functions, and investigating on its relationship with biotic and abiotic components of its habitat is considered as autecology of that plant species. This type of studies provide valuable information which is necessary for rangeland ecosystems management. ...
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Studying the behavior and the way a plant species functions, and investigating on its relationship with biotic and abiotic components of its habitat is considered as autecology of that plant species. This type of studies provide valuable information which is necessary for rangeland ecosystems management. This research was conducted to study the autecology of Stipa barbata. In this study, some topographic, climatic, and edaphic characteristics of the rangeland ecosystem, in which the plant species grows, were determined. Names of accompanied plant species in the ecosystem were listed. Based on physiognomy, this plant is the dominant species in most of its habitats. Its canopy cover, density, and frequency are 4.5%, 32750 plant/ha, and 82.5%, respectively. Phenology, root system, and the way of presence of Stipa barbata in the ecosystem were evaluated. The results showed that the habitats of this species are located in elevation range of 890 to 3300 meters above sea level while the major habitats are include elevation range of 1100 to 2800 meters above sea level. The species grows on slopes of 0.5 to 100%. Mean annual precipitation are 221 mm and 485 mm in Eshtehard and Zidasht Taleghan, respectively. Mean annual temperature are 15.5 and 24.5 degree Centigrade in Firoozkooh and Rood Shoor, respectively. The habitats for this plant species include very shallow to deep soils. Vegetative growth starts in early March and ends in early April. Its flowering stage is from mid May to mid June. Seed ripening stage is from late June until mid July. The plant has a shallow fibrous root system.
Farhad Azhir; Amrali Shahmoradi
Volume 14, Issue 3 , January 2007, , Pages 359-367
Abstract
Accessibility to a major portion of information about vegetation cover function of rangeland ecosystem is provided by the way of autecological study of range plant species. Autecological study of a range plant named Ferula ovina was accomplished in Tehran province. Topographic, edaphic, and climatic ...
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Accessibility to a major portion of information about vegetation cover function of rangeland ecosystem is provided by the way of autecological study of range plant species. Autecological study of a range plant named Ferula ovina was accomplished in Tehran province. Topographic, edaphic, and climatic characteristics of the species's habitat were determined. The canopy cover, density, frequency, and preference value of the plant were measured. Names of other species which are accompanied with Ferula ovina in its major ecosystem were listed. The results showed that habitat elevation for this species is 2000 to 3200 meters above sea level. Topographic aspect is not a major limitation for its growth. At its habitats, average annual precipitation is about 400 mm. Mean annual temperature is 8 centigrade. Its major ecosystem includes geological layers of tuff, limestone, shale, conglomerate, sandstone, siltstone and clay stone. This plant prefers loamy and/or sandy-loamy soils. Electrical conductivity of soil at different parts of the habitat indicates less than 1.0 ds/m. A range of 7.0 – 7.5 was observed for soil pH. In rangelands in which vegetation is dominated by this species, its percent canopy cover, frequency, and density are 12.35% , 81.62%, and 16750 plants per hectare, respectively. Its root system includes a main root and a few distributed roots. Vegetation growth of this plant starts in early May. Its flowering stage is in 5th to 20th of June, and seed ripening stage is in the fourth week of June. The plant propagates only by seeds. When plant is green, it is not grazed by livestock such as sheep and goat. However, it is harvested and stored as livestock fodder in fall and winter. The main insect seen on the plant is a butterfly named Malocosma sp.