Hasan Ahmadi; Ali asghar Mohammadi
Volume 17, Issue 3 , October 2010, Pages 340-352
Abstract
Since wind or water erosion is a phenomenon that causes waste of soil, it is necessary to combat soil erosion through soil conservation practices. Currently, some models have been developed to estimate erosion which should be examined with other existing models in different regions. In this study, ...
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Since wind or water erosion is a phenomenon that causes waste of soil, it is necessary to combat soil erosion through soil conservation practices. Currently, some models have been developed to estimate erosion which should be examined with other existing models in different regions. In this study, PSIAC and EPM models were evaluated in one of the sub watersheds of Hableh rood (Dehnamak) with effects of geomorphologic factors. First of all, using available information and producing required maps at the level of hydrologic units and sub-watersheds existing factors in the models were analyzed in the study area. With regards to lack of statistics and information of MPSIAC model, this model was not used, but to complete PSIAC model geomorphology map and geomorphology faces were produced. The results of sediment estimation using mentioned models indicated that two models of PSIAC with effect of geomorphology and EPM had same results to some extent. In conclusion, comprehensiveness and completeness of PSIAC model, PSIAC with effect of geomorphology factors is recommended to estimate sediment.
Gholam reza Zehtabian; Mehrnush Ghadimi; Ali Tavili; Jamal Bakhshi
Volume 17, Issue 3 , October 2010, Pages 353-361
Abstract
This research was performed to investigate the relationship between environmental factors including water and plant composition. In other words, determining the most effective factors in distribution of vegetation types in Arak playa was the main aim of this study. To achieve this goal, the initial map ...
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This research was performed to investigate the relationship between environmental factors including water and plant composition. In other words, determining the most effective factors in distribution of vegetation types in Arak playa was the main aim of this study. To achieve this goal, the initial map of vegetation was provided and afterward water and vegetation sampling was done. Water parameters including K, Na, CL, Mg, %Na (exchangeable sodium percentage), Th, SAR, Co3, Hco3, So4, TDS (total hardness), EC, pH, and anions (sulfates, bicarbonates and chlorates) were measured. Multivariate data analysis techniques including principal component analysis (PCA) and canonical correspondence analysis (CCA) were used to analyze the collected data. The results showed that vegetation distribution pattern was mainly related to water characteristics such as Mg, TDS, Cl, anion, EC and Th. it can be concluded that according to habitat conditions, ecological needs and tolerance range of each plant species have significant relationship with water properties.
Taghi Mir haji; Abbas ali Sanadgol; Mohammad hasan Ghasemi; Soheila Nori
Volume 17, Issue 3 , October 2010, Pages 362-376
Abstract
Phenology of four range species including Elymus transhircanus, Elytrigia libanotica Stipa bromoides and Stipa capillata were studied in Homand Absard Research Station, 70 km far from east Tehran, for five years (2003-2007). 20 plants were selected for each species and four important phenological stages ...
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Phenology of four range species including Elymus transhircanus, Elytrigia libanotica Stipa bromoides and Stipa capillata were studied in Homand Absard Research Station, 70 km far from east Tehran, for five years (2003-2007). 20 plants were selected for each species and four important phenological stages including early and vegetative growth, flowering, seed milk stage, seed maturity and autumn regrowth were recorded. Data recording was done once each week and once 15 days in growing and inactive seasons respectively. Phenological data were recorded during five years and interpreted using climatic data (temperature and precipitation) to calculate Growth Degree Days in each stage. The purpose of this study was to identify and introduce important phenological stages with a view to livestock grazing and farm management based upon phenology and Growth Degree Days. The results showed that onset and end of growth varied in different years and these changes occurred based upon temperature. Phenological period of all studied species in cool years was longer than that of warm years. But required Growth Degree Days for all mentioned species were almost similar. For example, Elytrigia libanotica required 833.3, 830.8, 834, 832 and 846.3 GDD for vegetative stage in 2003, 2004, 2005, 2006 and 2007 respectively. For flowering stage, 1342.1, 1342.8, 1355, 1344.8 and 1346.3 GDD were calculated from 2003 to 2007. In other words, Elytrigia libanotica species needs the mentioned GDD so that it can start seed milk stage. Start of growth varied in different years according to plant type and climatic condition and it was usually from mid to early March. Active growth continued to early July and then stopped. All studied species had an autumn regrowth in wet season.
Bagher Arayesh; Faraj... Hosseini; Mahdi Mirdamadi; Eeraj Malek mohammadi
Volume 17, Issue 3 , October 2010, Pages 377-392
Abstract
The purpose of this study is to compare the viewpoint of experts and utilizers of natural resources on people participation in the process of preservation, restoration, development and utilization of forests and rangelands in Ilam province. The present study is practical type with a cause -and –effect ...
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The purpose of this study is to compare the viewpoint of experts and utilizers of natural resources on people participation in the process of preservation, restoration, development and utilization of forests and rangelands in Ilam province. The present study is practical type with a cause -and –effect research method. Statistical population included all experts of Ilam Natural Resources Office and utilizers of natural resources. Sample size of experts and utilizers was calculated using Cochran formula included 56 users and 317 experts. Stratified and cluster sampling and simple random sampling were used for utilizers and experts respectively. Questionnaire was applied for collecting the data. The reliability of the questionnaire was obtained from cronbach's alpha (α=%88). To analyze the data, nonparametric tests such as x2, mann- whiteny, and Kruskal Wallis were applied. The results indicated that there was a significant difference between experts and users regarding protecting and reviving of natural resources, while no significant differences were observed between them with relation to development and utilization of natural resources.
Jamal Imani; Ali Tavili; Esaa Bandak; Bahram Gholinejad
Volume 17, Issue 3 , October 2010, Pages 393-401
Abstract
Analysis of vegetation is one of the important factors in appropriate management of rangelands. The current research was conducted to evaluate canopy cover percentage, forage production, and species density in four areas including reference area, personal rangeland, key area and critical area in the ...
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Analysis of vegetation is one of the important factors in appropriate management of rangelands. The current research was conducted to evaluate canopy cover percentage, forage production, and species density in four areas including reference area, personal rangeland, key area and critical area in the region of village. In each area, 5 transects were established on which 10 quadrate 1 m were used with regard to the plant type and distribution of species. The lengths of each transect and the distance between them were determined 100 m and 20 m respectively according to the species density and distribution. Canopy cover percentage, forage production and species density were recorded in all quadrates. Clipping and weighing method was used to estimate forage production. Data analysis was performed using one way ANOVA and Duncan test. Results indicated that there was significant difference in canopy cover percentage (p≤ 0/1), forage production (p≤ 0/05) and species density (p≤ 0/01) among 4 studied areas. The result showed that with moving from reference to critical area, canopy cover percentage, forage production and species density dramatically decreased as palatable species (class I), average palatable species and non palatable and invasive species had the most canopy cover percentage, forage production and density respectively in reference area, personal rangeland and common area between village and critical area. Perennials and palatable grasses such as Bromus tomentellus and Hordeum bolbosum had the highest canopy cover percentage, forage production and density in reference area. With a gradual increase in grazing intensity, percentage of palatable species decreased while non palatable species like Boisseria squarrosa and Centaurea virgata increased. This research revealed that heavy grazing jeopardized the sustainability of the rangeland ecosystem by creating unfavorable changes in vegetation characteristics.
Saeid Gharachelo; Mohamad reza Ekhtesasi; Mojtabah Zareian Jahromi; Mohamad bagher Samadi
Volume 17, Issue 3 , October 2010, Pages 402-420
Abstract
Nowadays, desertification is one of the ecological crises of the world. To control desertification, having a clear understanding of its factors and processes is necessary. Khezr Abad-Hemat Abad region of Yazd with area of 242 Km2 was considered to evaluate current condition of desertification using ICD. ...
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Nowadays, desertification is one of the ecological crises of the world. To control desertification, having a clear understanding of its factors and processes is necessary. Khezr Abad-Hemat Abad region of Yazd with area of 242 Km2 was considered to evaluate current condition of desertification using ICD. Iranian Classification of Desertification (ICD) was presented by M. Ekhtesasi and S. Mohajeri in 1995. First of all, available data were collected and basic studies were done. The data were entered in GIS and basic maps were produced through interpretation of aerial photos and satellite images using Arcview and Ilwis software. Eight desert homogenous units were separated according to the studies and by overlaying geomorphology, land use and vegetation cover maps. In next stage, effective factors in desertification including three environmental factors, three anthropogenic factors, soil erosion index, resilience potential and reconstruction of ecosystem were scored in a range of 0-10. Afterward, according to the sum of scores and comparing with table of desertification severity index, final desertification map was produced. The result showed that 81.53% of the region was in middle class of desertification while 18.47 % was in severe class. The environmental factors were determined as the main factor in desertification of 81.53 % area of the studied region while 18.47 % of that was affected by anthropogenic factors. Most main criterion in desertification of this region was water degradation process
Hamed Zarif Ketabi; Amr ali Shahmoradi; Majid Dashti; Asghar Paryab; Gholam reza Hosseini-Bamrood; Sadegheh Zarekia
Volume 17, Issue 3 , October 2010, Pages 421-430
Abstract
Melica persica is a perennial grass from Poaceae family with a partly wide adaptability which makes it an important range plant species, especially for soil conservation. It is native to Iran and mostly grows in Irano-Torani and Hirkani regions. To study autecology of Melica persica, its habitats in ...
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Melica persica is a perennial grass from Poaceae family with a partly wide adaptability which makes it an important range plant species, especially for soil conservation. It is native to Iran and mostly grows in Irano-Torani and Hirkani regions. To study autecology of Melica persica, its habitats in Khorasan region were identified and habitat characteristics including climate, topography and soil were investigated in several sites. Afterwards, regeneration, phenology, density, canopy cover, root system and chemical compositon of forage were also studied. The results indicated that distribution of M. persica was partlywidefrom north to south of khorasan region and especially in rocky foothills (altitude 900-2900 m). It was laso seen in all geographic aspects and a slope of 12-89 percent. M. persica habitats are mainly located in 3 climates of very cold semi-arid, very cold mediterranean and cold semi-arid. Mean annual temperature and precipitation of M. persica habitats differ from 5-15 degrees centigrade and 125-600 mm, respectively. This plant prefers well-drainaged soils of gravelly loam, gravelly silty loam and gravelly sandy loam texture. Optimal pH and EC are 7 to 8 and 0.5-1.5 ds/m respectively. Rocky soils and specially sheil, volcanic and lime stones are the main bed for its establishment. Vegetative growth of this plant starts from mid March and continues to mid May. Depending on altitude, heading stage starts from early May to late May. During late May to early June seeds are at milk stage and seed dissemination happens 20 days later. Results also showed that the effect of seed storage period on seed viability was non-significant. Plant natural regeneration is mainly via seed. Forage chemical composition analysis showed a protein of 21.6 and 8.1 % in vegetative and flowering stages respectively.
Farhad Zolfaghari; Ahmad Pahlevanravi; Akbar Fakhireh; Mitra Jabari
Volume 17, Issue 3 , October 2010, Pages 431-444
Abstract
Agh Toghe basin is in the central part of Marave Tapeh located in the east of Golestan province. In this research, study area was investigated based on Braun-Blanquet to identify plant communities. Afterward, relationship between environmental factors particularly slope, elevation, vegetation cover and ...
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Agh Toghe basin is in the central part of Marave Tapeh located in the east of Golestan province. In this research, study area was investigated based on Braun-Blanquet to identify plant communities. Afterward, relationship between environmental factors particularly slope, elevation, vegetation cover and soil properties including sand, silt, clay, acidity, electrical conductivity, and organic matter were determined using Principal Component Analysis (PCA). .Data collecting was carried out through establishing 103 quadrates based upon minimal area method in different vegetation types. A matrix of vegetation and soil characteristics was prepared and ordination was applied by PCA. The results showed that the most important factors in separation of vegetation types were as follows: elevation, slope, carbon percentage, sand, silt, clay and acidity.
Ali akbar Shamsi pur; Kazem Alavi panah; Hossein Mohammadi
Volume 17, Issue 3 , October 2010, Pages 445-465
Abstract
The purpose of this study is to track and analyze the environmental effects of droughts by remote sensing indices in Kashan desert and dry zone. Temporal changes of droughts was evaluated using normal Z index in annual and seaonal (spring) scales. Spectral and thermal data from data series of NOAA-AVHRR ...
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The purpose of this study is to track and analyze the environmental effects of droughts by remote sensing indices in Kashan desert and dry zone. Temporal changes of droughts was evaluated using normal Z index in annual and seaonal (spring) scales. Spectral and thermal data from data series of NOAA-AVHRR satellite between 1998 and 2004 were used to determine the drought indices. Vegetative and thermal drought indices were calculated using NDVI, VCI and TCI values derived from NOAA-AVHRR data. Results from applying mentioned indices showed that this area had low vegetation index values as NDVI index was generally less than 0.2. According to NDVI and VCI maps, years of 2000 and 2001 were characterized as drought condition contrary to 2002 and 2004 as rainy years.However, land surface temperature (LST), TCI and VHI indices showed different temperature conditions specifically in the months of April and May. Using validation of results derived from remote sensing indices, test of significance between them and climatic indices was calculated.According to the calculations, climatic condition of the study area was more compliant with the results of vegetation indices. Also thermal condition of the environment was more accurately indicated by thermal indices. According to the results, applying remote sensing data in environmental studies of arid and desert regions like Kashan is recommended.
Ali Tavili; Salman Zare; Reza Yari
Volume 17, Issue 3 , October 2010, Pages 466-475
Abstract
Nowadays, with regard to the global view of desert issue and necessity of using adaptable species in combat desertification, it is urgent to identify and remove the constraints of their production and establishment. Ammodendron persicum is one of the important and compatible species in desert ecosystems. ...
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Nowadays, with regard to the global view of desert issue and necessity of using adaptable species in combat desertification, it is urgent to identify and remove the constraints of their production and establishment. Ammodendron persicum is one of the important and compatible species in desert ecosystems. The current research was carried out to investigate the effect of different treatments on seed dormancy breaking and germinationstimulation ofAmmodendron persicum in order to determine the most effective treatment in enhancing of germination and primary growth of seedlings .The experiment was done in a Randomize Complete Block Design (RCBD) with 8 treatments and 4 replications. Different treatments were applied including scarification plus sulphuric acid (H2SO4 98%) for 10 and 15 minutes, scarification with sandy paper, scarification plus putting the seeds in hot water for 10 and 15 minutes, KNO3 (0.1 and 0.2 %), a complex treatment of scarification and KNO3 (0.1 and 0.2%) and distilled water as control treatment .To analyze the data, ANOVA was used and Duncan test was applied to compare the means. The result showed that scarification with sandy paper had the highest effect onseed dormancy breaking and seed germination stimulation of A. persicum as germination percentage increased from 3% in distilled water to 68% in scarification treatment.
Abdolhamid Papzan; Nashmil Afshazadeh
Volume 17, Issue 3 , October 2010, Pages 476-488
Abstract
Human being, now and in future, absolutely requires natural resources to continue his life especially rangelands as the most vital bed for sustainable development of environment and ecological phenomena, main feed supply for livestock in traditional animal husbandry system and so forth. Rangelands with ...
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Human being, now and in future, absolutely requires natural resources to continue his life especially rangelands as the most vital bed for sustainable development of environment and ecological phenomena, main feed supply for livestock in traditional animal husbandry system and so forth. Rangelands with an area of 90 million ha, about 60% of the country area, have undeniable role in socioeconomic calculations of the country. Despite several plans designed for range improvement and management, rangelands are exposed to serious threats. It seems that recognition of beneficiaries' indigenous knowledge including nomads as the most main utilizer in rangelands is utmost important for range improvement. This current qualitative study was carried out to identify and document the indigenous knowledge of Kalhor tribe's nomads for native mechanisms of range management. Gilan e gharb city of Kermanshah province was selected in this research. Data collection was performed through techniques like PRA and RRA were used. According to the nature of qualitative research, targeted sampling was applied and collected data were analyzed using content analysis. Findings refers to issues such as rangeland classification based upon slope, animal unit, rangeland segmentation, some native strategies in range management like migration, range analysis and so forth.
Hamid reza Mehrabi; Mohammad reza Chaichi; Reza Tavakolafshari; Hasan Madah Arefi; Ghavamodin Zahedi Amiri
Volume 17, Issue 3 , October 2010, Pages 489-498
Abstract
Applying methods like seed coating which result in germination improvement, reduction of environmental stresses and increase of range species establishment is utmost important. This experiment was performed to evaluate the effect of different seed coating methods on Sanguisorba minor seed germination ...
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Applying methods like seed coating which result in germination improvement, reduction of environmental stresses and increase of range species establishment is utmost important. This experiment was performed to evaluate the effect of different seed coating methods on Sanguisorba minor seed germination under drought stress and different sowing depths. A factorial experiment in a completely randomized design with three replications was conducted in this research. Treatments included three soil moisture levels (9, 14 and 21 percent of soil dry weight), two sowing depths (surface and three times the diameter of seed), and four seed coatings (control or no seed coating, organic matter, hydro gel and clay seed coatings). Germination percentage was recorded during the experiment. The results of main treatments showed that regardless of the coating type, the effect of all three coating materials on seed germination percentage was significant (p<0.01). The triple interaction effects of soil moisture, sowing depths and coating materials indicated that in surface sowing and all soil moisture levels, there was a significant difference (p<0.01) in seed germination percentage between seed coating and control treatments. No germination was observed in control treatment with 9% soil moisture and surface sowing. Germination percentage for control treatment with 14% soil moisture was 20% recorded as the second rank among the lowest germination levels. In treatment of three times the diameter of seed as sowing depth with 21% soil moisture, there was no significant difference in germination percentage between control and seed coating treatments.