Mohsen Armin; Hassan Ahmadi; hasan Rouhipour; Ali Salajegheh; mohammad Hossein Mahdian; Vajihe Ghorban nia kheybari
Abstract
Due to the constraints in determining of soil susceptibility to water erosion or soil erodibility through field tests, use of laboratory methods on small soil samples, are easy to implement and far less expensive and time-consuming. among different laboratory methods based on the soil properties, those ...
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Due to the constraints in determining of soil susceptibility to water erosion or soil erodibility through field tests, use of laboratory methods on small soil samples, are easy to implement and far less expensive and time-consuming. among different laboratory methods based on the soil properties, those relating to aggregate stability have received much attention. In this study, by relying on observations and changes in the macroscopic scale of homogeneous work units in marly soils of taleghan watershed, with 3260 hectares in area, 84 points as the soil sampling points were selected.In order to distinction between aggregate breakdown mechanisms and assessing of soil structural behavior in different environmental conditions, aggregate stability is measured with respect to three treatments fast wetting, slow wetting and stirring after pre-wetting using Le Bissonnais method. Results showed that aggregate breakdown mechanisms have a significant influence on aggregate stability. The instability main mechanism of marly soils in Taleghan watershed is slaking that caused by the compression of entrapped air during fast wetting and this situation can occur during rain storms on dry soils and irrigation flooding. So it seems that the method of agricultural land irrigation can be one of the most important soil erosion factors in the study area.
Hossein Arzani; javad Motamedi; Farhad Aghajanlu; Saeid Rashtvand; Azin Zareii
Hossein Azarnivand; Sedigh MOhammadi; Sadegh Hossein niyaee; Pouyan Dehghan
Abstract
One of the best methods to prevent or reduce soil erosion, it is preserving and restoring vegetation. So knowledge about the characteristics of the vegetation, including ecological features as the first and most important biological tool for soil conservation is essential. Coma (Ferula hausskenechtii) ...
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One of the best methods to prevent or reduce soil erosion, it is preserving and restoring vegetation. So knowledge about the characteristics of the vegetation, including ecological features as the first and most important biological tool for soil conservation is essential. Coma (Ferula hausskenechtii) Plant of Apiaceae family, which is abundant in the mountainous regions of Kurdistan. Regarding the importance this species to protect and prevent soil erosion that the proper species is to reform the mountainous rangelands. Therefore, Autecology studies is necessary. For this study, the main habitat of this species were determined by using vegetation maps with a scale of 1: 25,000 in Kurdistan province. Finally, five sites (Saral Divandarreh, Sarshiv Marivan, Buin-e Baneh, North West Dam Qshlagh, and Sarshiv Saqqez) were selected as sample. Then studies of vegetation, soil analysis, chemical analysis, root system and phenology of species was performed. The results showed that this species grows well at the altitude of 3000-1600 mask with 700-400 mm rainfall as well as its density decreases with increasing altitude. Its habitat soil has a neutral pH to slightly alkaline (7-8), is shallow or deep and medium texture. Vegetative growth starts of the first week of April and the plant is seeding in mid- June. This plant has multiple roots system, which average root length and the number of rootlet are 102 cm and 11 respectively. The highest amount of crude protein in the growth and the lowest is in seeding stage.
Zahra Barati; Ebrahim Omidvar; Ataollah Shirzadi
Abstract
Landslide susceptibility mapping is considered as the first important step in landslide risk assessment. The main purpose of this study is to compare the performance of a machine learning algorithm (a logistic model tree), and a statistical model (a logistic regression), for landslide susceptibility ...
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Landslide susceptibility mapping is considered as the first important step in landslide risk assessment. The main purpose of this study is to compare the performance of a machine learning algorithm (a logistic model tree), and a statistical model (a logistic regression), for landslide susceptibility modeling in the Sarkhoon watershed, Chaharmahal and Bakhtiari province. For this purpose, at first, a landslide inventory map including a total of 98 landslide locations was constructed using historical landslides, and extensive field surveys. In addition, a total of 100 non-landslide locations were also identified to construct a database. The landslide and non-landslide locations were randomly selected and divided into two groups with a 70/30 ratio for modelling and validation processes. Twenty conditioning factors were selected based on literature review and geo-environmental properties in the study area. Subsequently, the logistic model tree (LMT) and the logistic regression (LR) models were applied to identify the influence of conditioning factors on landslide occurrence. Finally, the performance of the models in landslide susceptibility mapping was investigated using the area under the receiver operating characteristics curve (AUC). The results concluded that the LR model (AUC = 0.797) outperformed and outclassed the LMT (AUC = 0.740) model in the study area. Although both models were reliable tools for spatial prediction of landslide susceptibility; however, the LR model was more accurate that it can be proposed as an alternative tool for better management of areas prone to landslide in the study area.
Mojtaba Piri; Alireza Khavaninzadeh; Hamid Sodaeizadeh
Abstract
Effect of Salicylic acid as a pre-treatment, on germination indices of Foeniculum vulgare Mill, Cynara scolymus L. and Nigella sativa under salinity stress was evaluated by a factorial arrangement in a completely randomized design with four replications. Salicylic acid and salinity were considered in ...
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Effect of Salicylic acid as a pre-treatment, on germination indices of Foeniculum vulgare Mill, Cynara scolymus L. and Nigella sativa under salinity stress was evaluated by a factorial arrangement in a completely randomized design with four replications. Salicylic acid and salinity were considered in 4 levels (0, 0.5, 1 and 2 mM) and (0, 50, 100 and 200 mM) respectively. The results showed that salinity and pre-treatment of salicylic acid significantly affect all indices of germination of three species. Results showed increasing salinity led to decreasing the most measured germination traits. Pre-treatment with salicylic acid improved all germination indices under salinity stress conditions compared to control seeds for all three species and resistant to salinity is decreased in Cynara scolymus L. Foeniculum vulgare Mill, and Nigella sativa respectively. The highest percentage ( more than 96%) and rate of germination in Cynara scolymus was observed at levels of 0.5 and 1 mM salicylic acid ( more than 3.4 n/day). The most improvement of germination traits in Cynara scolymus L., and Nigella sativa was observed at pretreatment 0.5 and 1 mM and for Foeniculum vulgare at 1 mM. Therefore, it can be concluded that the use of salicylic acid as a pre-treatment improves the germination traits of Artichoke, Corn cockle and Fennel under salinity stress at different concentrations.
M Jafari; M Tahmoures; M. Naghiloo
Volume 62, Issue 1 , June 2009
Abstract
The use of GIS tools is one of the newest methods for performance of different land evaluation and planning projects. This research with the purpose of determination of appropriate landuse to natural land potential and improvement of land management of catchments was executed using GIS-tools in Taleghan ...
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The use of GIS tools is one of the newest methods for performance of different land evaluation and planning projects. This research with the purpose of determination of appropriate landuse to natural land potential and improvement of land management of catchments was executed using GIS-tools in Taleghan area. At first ecological and socio-economic resources determined, mapped and entered to GIS environment. Then by analysis of more than 15 information layers, homogeneous and ecological units determined. By the use of watershed management and combined land planning model and in accordance with natural and socio-economic characteristics of the watershed, suitable landuses were proposed. At last optimum landuse map and the existing state of landuse map were adapted in GIS space. The results showed that 17 percent of the watershed area has suitable landuses while 83 percent of the watershed area needs landuse change.
mina pouresmaeel; ali salajegheh; Arash Malekian; amirreza keshtkar
Abstract
The complexity of the urban environment makes it difficult to consider all the vulnerable components of the urban. Hence, decision-making in urban environments is one of the most important issues in modern management. As a result, the purpose of this study is to investigate the urban vulnerability of ...
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The complexity of the urban environment makes it difficult to consider all the vulnerable components of the urban. Hence, decision-making in urban environments is one of the most important issues in modern management. As a result, the purpose of this study is to investigate the urban vulnerability of Azimiyeh in Karaj to flood based on multi-criteria decision-making method. The statistical population includes specialists who had sufficient knowledge and experience in the field of vulnerability management in urban areas. To this research, first, comprehensive knowledge of the factors affecting the urban vulnerability to floods was obtained using library studies, and then, the results of the Delphi technique, , was shown that among the primary indices, a total of 11 effective indicators were selected and a map of each of them was prepared using ArcGIS software. Then, the urban vulnerability to floods was calculated using the TOPSIS method. The study area was divided into 13 sub-areas based on runoff directional pattern and field observations, and then the decision matrix was made according to 13 sub-areas and 11 indicators. The results showed the vulnerability of this region to floods, which among the studied sub-areas, in sub-areas No. 1 and 2 observed the highest of flood vulnerability and the lowest of it observed in sub-area No. 13. Causes of flood vulnerability in the region include a direct connection to the upstream catchment that has lithology impermeable and geologically impermeable, high-density of building and population, and lack of proportionate open spaces.
Mohammad Reza Pirmoradi; Mohammad Moghaddam; Navid Yazdani
Abstract
Bitter asafetida (Ferula assafoetida L.) is one of the medicinal-rangeland plants belonging to Apiaceae family. The resin which is through incision secreted of the root has medicinal properties. The effect of rain on resin yield of this plant is one of problem of natural resources offices. The main aim ...
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Bitter asafetida (Ferula assafoetida L.) is one of the medicinal-rangeland plants belonging to Apiaceae family. The resin which is through incision secreted of the root has medicinal properties. The effect of rain on resin yield of this plant is one of problem of natural resources offices. The main aim of this study was to find out the effects of the irrigation on the resin yield, plants survival and some morphological traits of asafetida plants. Five irrigation treatments consisting of two times at week, one time at week, one time at two week, one time at three week, one time at month and without irrigation (control) were employed. The statistical design was a randomized complete block design, with four replications. The results show that irrigation increased resin yield, leaf length, vegetative growth period, survival plants at during of exploitation and next year significantly. But irrigation decrease essential oil percentage of resin significantly. One time irrigation in each week was the best treatment for increasing resin as it had produced 81.4 g resin yield per plant. The lowest resin yield was obtained in control and one time irrigation per month. These treatments had no effect on number of plant leafs. So plants irrigation before exploitation from this plant is recommended.
Mohsen Armin; mohammadrasul Rajabi; Fatemeh Barzegari Banadkooki
Abstract
we study the loss of fertility by analyzing the sediments retained behind check dams which was designed to control erosion and fixation of longitudinal profiles in the Safarood watershed of Ramsar during the years 1373 to 1388. For this purpose, soil losses were determined by determining the physicochemical ...
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we study the loss of fertility by analyzing the sediments retained behind check dams which was designed to control erosion and fixation of longitudinal profiles in the Safarood watershed of Ramsar during the years 1373 to 1388. For this purpose, soil losses were determined by determining the physicochemical properties of sediments deposited behind the selected check dams and comparing them with the same soil characteristics. In the analysis of physicochemical properties of soil, the results showed that most of the studied soils are of sandy, non-saline, neutral, calcareous and non-sodium. Based on the classification of organic matter, approximately 60% of the studied soils have poor structure and little structural stability and are often in the moderate class of erodibility. In the soil fertility loss section, the results showed that erosion leads not only to the loss of solid mineral components from the soil but also to the loss of organic matter and chemical nutrients. Changes in the properties of a soil due to erosion affect the level of fertility, basically as a result of a reduction of the effective depth. There is a significant reduction in the carbon and nitrogen contents and all macro and micronutrients. The losses of carbon, nitrogen, phosphorus, potassium, sodium, and total calcium and magnesium content in the study area were 6588.26, 1921.78, 19.71, 53.6, 19.89 and 503.13 g/ha/year respectively, which this level of loss is a serious threat to processes and activities related to soil fertility, including vegetation development in the region.
Leila Bakhshandehmehr; Saeid Soltani; Adel Sepehr
Abstract
According to the UNCCD definition, “Desertification” is land degradation in arid, semi-aridand dry sub-humid areas resulting from various factors, including climatic variations andhuman activities. It has been recognized as a major economic, social, and environmentalproblem in many countries ...
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According to the UNCCD definition, “Desertification” is land degradation in arid, semi-aridand dry sub-humid areas resulting from various factors, including climatic variations andhuman activities. It has been recognized as a major economic, social, and environmentalproblem in many countries of the world. The MEDALUS methodology is a practical approachto assess the present status of desertification and evaluate the desertification risk. In this study,a regional model has been developed to desertification assessment and mapping in the SEGZIplain (Eastern Isfahan) based on the MEDALUS methodology. At first step, seven criteriaincluding climate, soil, vegetation cover, ground water, water erosion, wind erosion and policyand management were recognized according to the local condition. Each criterion includedseveral indicators accounting as factor quality determination. These indicators quantified basedon their influences on desertification process. For each indicator a score ranging from 100 to200 were assigned and desertification weighting was finally extracted. The weight of eachfactor and the weight of desertification status was calculated by geometric mean. Ultimately,desertification status was classified in four levels including low, moderate, severe and highsevere. At last the maps of these results was produced by geographical information system.Results showed that 2% of the study area was classified as moderate class, 35% classified assevere and 63% involved high severe class. Climate, policy and management are the mostimportant factors have led to desertification process in this region.
Mohammad Mahdi Hoseinzadeh; Reza Esmaili; Mohammad Hasan Jouri; Samaneh Pourkalhor
Abstract
Gully erosion is one of the most destructive types of hydraulic erosion and an important process insoil destruction that in some cases creates long, vast, deep canals. Study area was located in thenortheastern Alborz, Mazandaran province and Nowshar County (Firozkola subbasin a portion ofKojur watershed). ...
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Gully erosion is one of the most destructive types of hydraulic erosion and an important process insoil destruction that in some cases creates long, vast, deep canals. Study area was located in thenortheastern Alborz, Mazandaran province and Nowshar County (Firozkola subbasin a portion ofKojur watershed). This paper examines gully morphometery in relation with physical and chemicalcharacteristics of soil. The morphometery of gullies such as width, depth and slope were determinedin field. Physical and chemical properties of soil such as exchange cation (EC), organic andinorganic carbon, soil acidity and soil texture were determined in the laboratory. Data analyses wereperformed by Detrended correspondence analysis (DCA). The DCA analysis indicated that thewidth and slope are correlated with OC and clay negatively but they have positive correlation withpH. Hence, it's expected that following reduction of OC and clay and an increase in PH, gully widthboosts. Besides, if EC increases and CaCO3 decreases, depth and w/d ratio of gully will increase.
Salman Zare; ali Tavili; ali Shahbazi; akbar Riyahi
Volume 63, Issue 1 , June 2010, , Pages 29-40
Abstract
The objective of this research was to evaluate the effect of different concentration of salicylic acid on enhancement germination characteristics of Sanguisorba minor L. under salt and drought stress. The experimental design was factorial arranged in a completely randomized block design with four replications. ...
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The objective of this research was to evaluate the effect of different concentration of salicylic acid on enhancement germination characteristics of Sanguisorba minor L. under salt and drought stress. The experimental design was factorial arranged in a completely randomized block design with four replications. Treatment were combination of 5 levels of salt and drought stress, separately (0, -0.3, -0.6, -0.9 and -1.2 Mpa) and 4 concentration of salicylic acid (0 as a control, 100, 200 and 300 mg/lit). The results revealed that all germination characteristics decreased by increasing strength of salt and drought stress but treated seeds showed lower decrease. Application of salicylic acid increased germination percentage and rate and also decreased mean germination time significantly, but had no effect on root, shoot and seedling length. Since 200 and 300 mg/lit concentrations of Salicylic acid had more effect than the 100 mg/lit on germination attributes, on the other hand no significant difference was observed between 200 and 300 mg/lit concentrations. Considering the economic issues and also considering this fact that higher concentrations of salicylic acid may lead to accelerated stress in plant, 200 mg/lit salicylic acid concentration was suggested in S. minor in order to improve germination and seedling establishment under salt and drought stress.
Soheila Pouyan; Mohammad Zare; Mohammad Reza Ekhtesasi
Abstract
Dust event is one of the common and destructive phenomenon in arid and desert regions. This phenomenon has negative impacts on human life and environment. Dust storms, in addition to soil loss, can cause and aggravate health problems, food production reduction, economical damages into the industrial, ...
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Dust event is one of the common and destructive phenomenon in arid and desert regions. This phenomenon has negative impacts on human life and environment. Dust storms, in addition to soil loss, can cause and aggravate health problems, food production reduction, economical damages into the industrial, agricultural and communication sections. Therefore, accurate investigative of this phenomenon is necessary. The aim of this research was regional analysis of dust storm index (DSI) in 44 meteorological stations of Iran. At first stage, the dust storm index for each station was calculated using hourly dust data. Next, monthly averages of dust storm index (DSI) were used for regional analysis using linear moments approach. Based on regional analysis, the study area is divided to six homogeneous dust storm index regions. Pearson Type III (PE3) and Generalized Logistic (GLO) distribution models were the best regional distribution models for 1, 4, 5, 6 homogeneous regions, and 2, 3 homogeneous regions, respectively. Estimation of the dust storm index and its regional analysis can be used in many environmental studies, decision making and management processes in relation to combating desertification and dust storms.
Shafagh Rastgar; Hossein Barani; Ali Darijani; Vahedberdi Sheikh; Jamshid Ghorbani; Mohammad Ghorbani
Abstract
Vegetation cover as the main factor affecting the water erosion plays an important role in preventingsoil loss. To this end, for better understanding the impact of vegetation cover on soil erosion andsediment yield over the major existing geological formations in the summer rangelands of Balade inthe ...
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Vegetation cover as the main factor affecting the water erosion plays an important role in preventingsoil loss. To this end, for better understanding the impact of vegetation cover on soil erosion andsediment yield over the major existing geological formations in the summer rangelands of Balade inthe Mazandaran province, rainfall simulation studies have been carried out using a portable rainfallsimulator. Among many geological formations across the study area, the three major lithological unitsof mica sandstone, clay and shale sandstone with coal seams of “SHEMSHAK”, structures of tuffshale and dark gray to green shale with volcanic rocks of “KARAJ” and limestone of “LAR” havebeen selected as lowly, moderately and highly resisting formations to degradation. For eachcombination of geological formation and vegetation cover (low, moderate, and high density) threesampling plots of 1x1m have been selected and rainfall simulation has been conducted over them. Foreach plot, the surface characteristics including the vegetation cover, runoff and sediment yield and soiltexture were measured. The measured data were statistically analyzed. Results showed that“SHEMSHAK”, “KARAJ” and “LAR” formations were respectively ranked from highest to lowestwith respect to the volume and weight of sediment yield. Also, there was a strong inverse relationshipbetween vegetation cover percentage and volume of runoff and sediment for all investigatedgeological formations specially in poor vegetation situation that indicate interaction effects betweenvegetation cover and type of geological formations.
Farzad Ahmadi; Ghodratollah Heidari; Faatemeh Shafiee
Abstract
The purpose of this research was to investigate the factors affecting the use of information resources and communication channels by the Dehgoln Township ranchers to participate in rangelands rehabilitation and restoration projects. The study consisted of all ranchers (N=80) in the Dehgolan county, located ...
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The purpose of this research was to investigate the factors affecting the use of information resources and communication channels by the Dehgoln Township ranchers to participate in rangelands rehabilitation and restoration projects. The study consisted of all ranchers (N=80) in the Dehgolan county, located in Kurdistan Province, among whom 68 ranchers were selected through random sampling technique. A questionnaire was designed and employed to gather the required data. A panel of selected experts verified the questionnaire's content validity. The scale of the use of information resources and communication channels was proved to be reliable since Cronbach Alpha coefficient was estimated as equal to 0.7. Data analysis was done through SPSS software version 22. The results of descriptive statistics revealed that majority of the ranchers were illiterate. In addition, it revealed that majority of the ranchers have utilized information resources and communication channels at a low level. The results of regression analysis finally revealed that three variables of income, educational level and family size, explained about 54% of the variances of the dependent variable.
Reza Omidipour; Ataollah Ebrahimi; Pejman Tahmasebi; Marzban Faramarzi
Abstract
Vegetation canopy cover (VCC) and Above-Ground Phytomass (AGP) are the most important indicators of rangeland ecosystem’s structure and function, therefore their accurate evaluation and monitoring is vital for ecosystem welfare. Vegetation indices, are essential tools for assessing and monitoring ...
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Vegetation canopy cover (VCC) and Above-Ground Phytomass (AGP) are the most important indicators of rangeland ecosystem’s structure and function, therefore their accurate evaluation and monitoring is vital for ecosystem welfare. Vegetation indices, are essential tools for assessing and monitoring VCC and AGP which have not been addressed under different managerial conditions, so far. In the present study, the effect of long-term grazing and enclosure (26-year) on the relationship between the VCC and AGP with vegetation indices were evaluated in the Sabzkouh protected area of ChaharmahalVaBkhtiari province using Landsat-8 images. VCC and AGP were evaluated in both grazed and enclosed area by 10 plots of 30*30-m in each of which three quadrates of 2×2 square meters were applied (totally 60 quadrates) in the June, 2016. The results indicate significant differences between grazed and enclosed areas in terms of VCC (57% and 46 respectively) and AGP (with 1656 and 1011 kg per hectare, respectively). The soil adjusted vegetation indices show a more significant prediction of VCC in enclosed and grazed areas (TSAVI1=0.828 and PVI3=0.884, respectively). The PVI2 index showed appropriate results for estimating AGP in both enclosed (R2=0.726) and grazed (R2=0.698) areas. The improved performance of these indies is mainly due to the adjustment of soil effects. Our results suggest that grazing caused a significant effect on the relationship between VCC and AGP with vegetation indices due to feasible changes in vegetation structure or composition. Therefore, using different indices is necessary to study and monitor different rangelands under management strategies.
s.m Hoseini; M.R Ekhtesasi; A.R Shahriyari; H Shafiei
Volume 63, Issue 2 , September 2010, , Pages 165-18
Abstract
Sistan plain is affected by desertification and this phenomenon has serious impacts on roads and socio- economic activities of local people of this region. The main purpose of this study is estimating the current and potential desertification intensity of Niatak region of Sistan based on MICD method. ...
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Sistan plain is affected by desertification and this phenomenon has serious impacts on roads and socio- economic activities of local people of this region. The main purpose of this study is estimating the current and potential desertification intensity of Niatak region of Sistan based on MICD method. That, through it the working units of this region were prepared as the base map for evaluating to consider the factors and indices by geomorphology method. Also, in order to prepare the desertification intensity condition for both current and potential situations of this region, the desertification intensity of various applications was determined and relative plans to current and potential desertification of each land use were prepared after evaluating wind erosion indices and accumulating their scores for each working unit based on reference tables. The results showed that in this region the desertification potential consists of medium (III), intensive (IV) and very intensive (V) classes, while current desertification condition includes low (II), medium (III) and intensive (IV) classes of desertification intensity, respectively. These variations were resulted by wind erosion control activities over recent years.
A. Afzali; M. Mahdavi; M. A. Zare Chahoki
Volume 62, Issue 2 , October 2009, , Pages 187-196
Abstract
The most precise and simple method of evaporation measurement is application of pans in which class A pan is used in Iran. In contrast, there are many empirical methods which are used for estimating the evapotraspiration. In this study, Thornthwaite method was used due to the simplicity of its parameters ...
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The most precise and simple method of evaporation measurement is application of pans in which class A pan is used in Iran. In contrast, there are many empirical methods which are used for estimating the evapotraspiration. In this study, Thornthwaite method was used due to the simplicity of its parameters and then we tried to use it for evaluating evapotranspiration by changing it's parameters. Because of its unproper estimation in Iran's climatic conditions in comparison with pan data we concluded that a considerable percentage of monthly evaporation with thornthwaite method with corrected alfa in different stations, have a good conformity with monthly evaporation measured with class A pan in the error range of 30% and in we added 0.5 unit to the exponent of Thornthwaite formula to having acceptable results for arid and semi arid region. In fact, the formula is not efficient in measurement of evapotranspiration without correction.
Asghar Tavakkoli Fard; Aliakbar Nazari Samani; Naser Mashhadi; Hoda Ghasemieh; Mojtaba Hodayi Arani
Abstract
Kashan Erg is one of the most important sand dunes complexes in Iran. It is included the most important various type of sand dunes in Iran. This study was performed to compare the granulometry of aeolian sediments in different sand dunes and also from plinth to crest of transverse dunes that located ...
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Kashan Erg is one of the most important sand dunes complexes in Iran. It is included the most important various type of sand dunes in Iran. This study was performed to compare the granulometry of aeolian sediments in different sand dunes and also from plinth to crest of transverse dunes that located in Kashan Erg’s north. In order to determining different statistical variables, aeolian sediment sampling was conducted in different sand dunes. Then, the sample’s granulometry test was done based on dry sieve analysis. Finally, statistical parameters such as mean diameter, Sorting, Skewness, Kurtosis, d10, and d90 were determined. The results showed that the mean diameter, Sorting, d10 and d90 parameters have significant differences at the 95% significance level between the stabilized sand dunes and active ones. Moreover, it was found that in transverse sand dunes, there are a significant difference at the 95% significance level between mean diameter and d90 parameters in bottom of the stoss side and lee side.
Zeinab Jafariyan; Leila Tayefeh Seyyed Alikhani; Reza Tamartash
Abstract
Carbon sequestration potential of three species including Agropyron elengatum, Stipa barbata and Artemisia aucheri was evaluated in parts of a semi-arid rangeland in this study. After determination and selecting key areas as study sites, sampling from vegetation and soil, based on randomized systematic ...
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Carbon sequestration potential of three species including Agropyron elengatum, Stipa barbata and Artemisia aucheri was evaluated in parts of a semi-arid rangeland in this study. After determination and selecting key areas as study sites, sampling from vegetation and soil, based on randomized systematic method, was done and 90 plant and 45 soil samples were taken, respectively. Shooting and rooting organs of the species were separated from each other after transfer to the laboratory and carbon sequestration coefficient of plant organs was determined with combustion method.Then carbon sequestration coefficient of different species, organs and soil under these species were analyzed. The results showed that carbon sequestration rate between studied three species, had significantly statistical difference (p
Omid Bayat; Hamid Karimzadeh; Mostafa Eghbal; Hossein Khademi
Abstract
Despite of suitable geological and climatic conditions for forming and evolution of alluvial fans and importance of this landform as soil and water resources in arid regions, there are limited studies about this landform in Iran. In the present study, evolution and pedogenic development of geomorphic ...
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Despite of suitable geological and climatic conditions for forming and evolution of alluvial fans and importance of this landform as soil and water resources in arid regions, there are limited studies about this landform in Iran. In the present study, evolution and pedogenic development of geomorphic surfaces of an alluvial fan in Eastern Isfahan were studied by using remote sensing, field and laboratory analyses. Results show that watershed of studied alluvial fan was tectonically active and two main depositional events were occurred for fans of Eastern Isfahan. Geomorphic surfaces were identified according to topographic position and pedogenic development. Geomorphic surfaces of studied alluvial fan were identified using topographic position, dissection rate and pedogenic development of soils. Using of dissection index for geomorphic surfaces suggest that this index is more expedient for use in active surfaces. Soils on geomorphic surfaces are calcareous with distinctive carbonates morphology. Results of dissection index are in corroboration with carbonates morphology in soils of geomorphic surfaces. So, morphology of pedogenic carbonates can be considered as an index of relative age of geomorphic surfaces. Usage of clay accumulation index also show great corroboration with results of dissection index and morphology of carbonates and application of this index is recommended for paleosols. Suggested systems for paleosol classification truly able to classify paleosols and application of these modern models recommend for other regions.
Masoomeh Salehi Mourkani; Salman Zare; Maryam Mombeni; Ghasem Ghoohestani; Khaled Ahmadaali; Bijan Khalili Moghadam
Abstract
The influx of quicksand in the desert areas of Iran causes damage to various aspects of life of the inhabitants of these areas. Oil mulching is one of the measures that has been used for many years to stabilize quicksands. Because oil mulch is made up of heavy petroleum products, it can contaminate water ...
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The influx of quicksand in the desert areas of Iran causes damage to various aspects of life of the inhabitants of these areas. Oil mulching is one of the measures that has been used for many years to stabilize quicksands. Because oil mulch is made up of heavy petroleum products, it can contaminate water resources in these areas with heavy elements and hydrocarbons by entering water sources. To investigate the effect of heavy elements and hydrocarbons on water resources, samples of oil mulch in short-term, medium-term and long-term periods from Hamidiyeh sands of Khuzestan province and also samples of oil mulch of Abadan refinery in laboratory conditions with Simulations of natural conditions and 24-hour residence time in contact with water were investigated. The results of this study showed that the amount of pollution of heavy metals other than elemental, which in the long-term, medium-term, short-term and control area increased by 95%, 115%, 123% and 129%, respectively, than the allowable limit. Oil mulch does not have a significant effect on increasing the pollution of water resources in terms of heavy elements. Examination of oil mulch on the amount of hydrocarbons in water showed that with the exception of Naphtalene and Benzo (g, h, i) Perylene, which decreased in the medium and short term compared to the control area, the difference of other hydrocarbons compared to the control area increased. Been; But in general, the amount of all hydrocarbons studied in the studied treatments was less than their allowable limit.
Mohammad Jafari; Mohammad Tahmoures; Mohsen Naghiloo
Abstract
The purpose of this research is investigation of relationship between vegetation cover and soil characteristics and determination of the most important soil factor that effects on quantity variations and kinds of vegetation cover in the study area. The study area is located in west of Tehran province ...
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The purpose of this research is investigation of relationship between vegetation cover and soil characteristics and determination of the most important soil factor that effects on quantity variations and kinds of vegetation cover in the study area. The study area is located in west of Tehran province and south eastern of Hashtgerd, next to Najm-abad village. After field study, the index vegetation types were selected and randomized-systematic sampling method has been used for soil and vegetation cover sampling in each of key area. The area of each plot was determined according to kind of plant species and species distribution using minimum area method. Some vegetation cover parameters such as canopy cover percentage, density and frequency of plant species were measured in the area. Then soil sampling were done from 2 horizon 0-10 cm and 10-30 cm in each plot and soil attributes such as texture, pH, organic carbon percentage and gypsum were measured in soil laboratory. Afterwards statistical methods like multivariate regression, analysis of variance and statistical techniques were used for analyzing of soil and vegetation cover data. Results showed that there is not any specific difference between soil and vegetation data except for gypsum. In other words the effective factor on vegetation cover variation was soil gypsum.
Mohammad Ansari Ghojghar; Masoud Pourgholam-Amiji; Shahab Araghinejad; Iman Babaeian; Abdolmajid Liaghat; Ali Salajegheh
Abstract
It is clear that the ENSO phenomenon affects the hydrological and climatic regimes in different parts of the world, but the extent of this effect in different parts of the world has not yet been answered. Therefore, this research has been done to answer this important question. In this research, using ...
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It is clear that the ENSO phenomenon affects the hydrological and climatic regimes in different parts of the world, but the extent of this effect in different parts of the world has not yet been answered. Therefore, this research has been done to answer this important question. In this research, using the Oceanic Niño Index (ONI), the effect of the positive phase of the El Niño-Southern Oscillation (ENSO) on the Frequency of Dust Stormy Days (FDSD) in 12 synoptic stations located in Khuzestan and Sistan and Baluchestan provinces over a period of 40 years (2019-1980) has been reviewed. For this purpose, hourly dust data, codes of the World Meteorological Organization, Adaptive Neural-Fuzzy Inference System (ANFIS) and time changes of FDSD index in two neutral phases and the occurrence of El Niño were used. The results of ANFIS model estimation and observational values of FDSD index showed that at the occurrence time of El Niño in Khuzestan and Sistan and Baluchestan provinces, equal to 33 and 17 events, respectively, the observable values of the frequency of days with dust storm were less than the estimated values. The results also showed that the positive phase of ONI is more effective on dust storms in Khuzestan province than in Sistan and Baluchestan province. Therefore, during the hot phase of ENSO, more measures should be taken to control and manage dust storms and their destructive effects in areas where the source of dust storms is external.
samira hajipuor; Hossein Barani; hassan yaganeh; Ahmad Abadi Sarvastani
Abstract
Observing livestock grazing time in rangelands is quite important for conservation of rangelands and protecting them against degradation. This study was aimed at assessessment of factors that contribute to observing grazing time in rangelands of Kouhdasht County in Lorestan province. This study is a ...
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Observing livestock grazing time in rangelands is quite important for conservation of rangelands and protecting them against degradation. This study was aimed at assessessment of factors that contribute to observing grazing time in rangelands of Kouhdasht County in Lorestan province. This study is a survey research and the statistical population is composed of nomadism pastoralists of Koohdash County. Based on Cochran formula, sample size was defined 310 persons out of 1038 pastoralists. Many different variables including socio-economic conditions of users and factors contributing to grazing management were assessed in this study. Among the econometric models, Logit Model was used in order to assess factors impacting on time management of grazing. Logit model parameters were estimated with maximum likelihood method. Coefficient of determination and accurate prediction percentage were used in order to assess the finesses of sample’s data. Results showed that there is a significant differencebetween different groups of users in terms of considering grazing time. Having winter pastures, early arrival date, and late exit of pastoralism from summer rangelands had the highest effect. Based on achieved results, when heads of families were pastoralists, households were much more dependent on rangelands as a source of livelihood. Therefore, they entered earlier to summer rangelands. Besides, those who did not have winter pastures were less inclined to care about grazing time. In this regard, if they are further supported through handy feeding, they will be motivated to observe grazing time. Kuhdasht is an active center in livestock farming. Entrance into and exit of livestock out of the rangeland leaves direct and indirect impacts upon local life. It has as well negative effects on rangeland vegetation. Defining factors that affect on livestock entrance and exit will help planners to take appropriate measures for removing problems.
