nayefe adak; Hossein Arzani; Sayed Mahdi Heshmatol vaezin
Abstract
Beekeeping is one of the agricultural production activities that can create employment with a small amount of investment. Beekeeping can be heeded as one approach to increase stakeholder’s income of rangelands, balance between livestock and rangeland resources, enhancing the economic status of ...
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Beekeeping is one of the agricultural production activities that can create employment with a small amount of investment. Beekeeping can be heeded as one approach to increase stakeholder’s income of rangelands, balance between livestock and rangeland resources, enhancing the economic status of the villagers and participation in range management plans. Zhiwar rangelands have great potential of land uses variety .Therefore in this study, we decided to determine the amount of increasing income from beekeeping. some of the factors that can affect the income of beekeepers were studied in this research. some of this factors include individual traits of beekeepers, the unit traits of beekeeping, the Costs, incomes. the datas of questionnaires in this study were collected by interview and filling out questionnaires. Questionnaire analysis was performed by using SPSS software. The results showed that the number of hives, the ratio of sugar to honey had significant impacts on the income of beekeepers and honey production. Among whole costs, sugar had the greatest proportion which causes decreasing in prices and thus, profitability. On one side the Increase of the percentage, causes the ascendancy in production and income, on the other side, it causes reducing in the costs and increasing in expenses. Thus, reducing the profitability is not only because of the high consumption of sugar, it may be also due to poor marketing. But the number of hives due to reducing average costs causes increasing profitability
Pouyan Dehghan; Hossein Azarnivand; Hassan Khosravi; Gholamreza Zehtabian; Alireza Moghaddam Nia
Abstract
The excessive reducing capacity of natural resources is one of the most important challenges that human beings have faced it in the last century. Proper land use and land use management based on its ecological potential play an important role in achieving sustainable development. Hence, in order to achieve ...
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The excessive reducing capacity of natural resources is one of the most important challenges that human beings have faced it in the last century. Proper land use and land use management based on its ecological potential play an important role in achieving sustainable development. Hence, in order to achieve sustainable development and in order to use land appropriately, tendencies should be directed towards the planning and utilization of resources on the basis of their resources. Therefore, since agriculture has a great deal of environmental impact on urban areas, the evaluation of agricultural lands is necessary. The aim of this study is evaluation of ecological potential of land in Eshtehard in terms of agriculture and rangelands. For this purpose, the ecological potential of the lands of Eshtehard was evaluated using ecological criteria and using Fuzzy, Fuzzy AHP methods and Geographic Information System (GIS). The Fuzzy method was used to standardize the layers and also to assign weight to each of the indices used by Fuzzy AHP method. The results of this study showed that class 1 lands with 1.50% is the lowest and the class 4 lands with 25.36% of the total area of the study area has the biggest area. The results of the analysis in this study indicate the high efficiency of Fuzzy AHP method in assessing the ecological potential of the area and can be used with changes necessary for other areas and also other location actives.
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.
Maryam Asadi; Ali Fathzadeh
Abstract
Understanding of suspended sediment rate is one of the fundamental problems in water projects which water engineers consistently have involved with it. Wrong estimations in sediment transport cause incorrect design and destruction of hydraulic systems. Due to the difficulty of suspended sediment measurements, ...
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Understanding of suspended sediment rate is one of the fundamental problems in water projects which water engineers consistently have involved with it. Wrong estimations in sediment transport cause incorrect design and destruction of hydraulic systems. Due to the difficulty of suspended sediment measurements, sediment rating curves is considered as the most common method for estimating the suspended sediment load. The main purpose of this research is the capability challenge of this method in comparison to some state of the art models. In this study, we selected some computational intelligence models (i.e. K-nearest neighbor (KNN), artificial neural networks (ANN), Gaussian processes (GP), decision trees of M5, support vector machine (SVM) and evolutionary support vector machine (ESVM)) and compared them with their sediment rating model in 8 basins located in Gilan province. Daily sediment and discharge data considered as the input data for 30-years. Evaluation of the results indicated that the Gaussian process model has the lowest residual sum of squares (RMSE) and the highest correlation coefficient (r) than the other models.
isa Jafari Foutami; Esmaeil Sheidai Karkaj
Abstract
The purpose of this study was to investigate the causes of uncertainty in different methods of estimating soil carbon and also to evaluate the proposed computational method that eliminated the effect of soil bulk density on carbon calculation and the actual soil carbon content for soils with different ...
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The purpose of this study was to investigate the causes of uncertainty in different methods of estimating soil carbon and also to evaluate the proposed computational method that eliminated the effect of soil bulk density on carbon calculation and the actual soil carbon content for soils with different bulk densities in terms of the equivalent depth.Therefore, in order to check the accuracy of this proposed method, the amount of carbon in three types of grazing intensity in Golestan province (light grazing, average grazing intensity and severe grazing) was calculated and various methods were tested and analyzed. The results of mean comparison showed that based on first approach (concentration carbon Parameter), amount of carbon in first depth of light grazing area, moderate grazing and intensity grazing have significant differences, and soil concentration are 31.39, 23.57 and 11.5 gr C/kg soil, respectively, However, contradictory results achieved for first depth in case of present the mass soil in per unit area based on constant depth. So that the first depth of the light and medium grazing intensity have more mass carbon, 89.15 and 74.47 ton C/ ha, respectively, and heavy grazing intensity site has the lowest, 42.93 ton C/ ha. There are also these uncertainties between two different depths for different sites. In order to dissolved this conflict in several studies, mass carbon based on equivalent depth was calculated for study area and result show that light and heavy grazing area have the highest and the lowest amount of carbon.
Alirostam Khanizadeh; Reza Erfanzadeh; Reza Siahmansur
Abstract
The aim of this study was to quantify the response of Bromus tomentellus, Hordeum bulbosum and Agropyron trichophorum to continuous grazing of sheep in semi-arid rangelands of Lorestan. In two areas, grazed and ungrazed, 4 transects of 200 meters were established and 10 random points were selected along ...
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The aim of this study was to quantify the response of Bromus tomentellus, Hordeum bulbosum and Agropyron trichophorum to continuous grazing of sheep in semi-arid rangelands of Lorestan. In two areas, grazed and ungrazed, 4 transects of 200 meters were established and 10 random points were selected along of each transect and at each point the nearest plant considered for further study. Morphological traits of each selected plant were measured i.e. height, internode distance, root length, root weight, production and mass. After reviewing the data normalization, the averages between grazed and ungrazed were compared by non-paired t-test. The effect of livestock grazing on height, shoot internode, length and root weight, biomass and yield of H. bulbosum and A. trichophorum were significant. The mean weight of H. bulbosum in the ungrazed and grazed areas was 117.1 gr and 16.1 gr, respectively, and the height of A. trichophorum was 525.1 mm in the ungrazed and 334.7 mm in the grazed areas, respectively. Grazing of livestock had no significant effect on the height and internode distance of B. tomentellus (p>0.05). Animal grazing significantly increased root length of 58.35 mm in B. tomentellus. In general, the results of this study showed that different species of plants exposed different reactions and trade-off against grazing depending on the type of plant species. Knowledge about of the morphological changes of plant species against grazing can greatly help us for the management of sustainable grazing in the rangelands.
somaieh dehdari; nezam armand; mohammad faraji; nasim arman; fatemeh hadian
Abstract
The study aimed to evaluate the effects of Karon 3 and 4 dams on land use and cover changes, for this aim 4 images over 28 years (taken in 1985, 2003, 2009 and 2013) were obtained and geometric, atmospheric and topographic corrections were applied. Maximum likelihood and post-classification techniques ...
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The study aimed to evaluate the effects of Karon 3 and 4 dams on land use and cover changes, for this aim 4 images over 28 years (taken in 1985, 2003, 2009 and 2013) were obtained and geometric, atmospheric and topographic corrections were applied. Maximum likelihood and post-classification techniques were used to detect land use/cover changes and their accuracy then was assessed using topographic maps and field works. The overall classification accuracy and Kappa statistics for all the maps were more than 0.79 and 86.24% respectively. The classification map of year 2009 indicated that about due to Karron3 dam and 6734.88 hectares because of rangeland and forest were destroyed. Classificated map of 2013 indicated about 5127.39 hectares increased because of Karon 4 too. The overall findings of this study indicate that forest and range land degradation in the region, is due to the construction of Karun 3 and 4.
ALIREZA Arabameri; khalil rezaei; mojtaba yamani
Abstract
Gully erosion is one of the erosive processes that mostly change the shape of the earth surface and has severe environmental and economic damages. The aim of this research is modeling between geo-environmental parameters effective in gully erosion and gully occurrence in the study area and gully erosion ...
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Gully erosion is one of the erosive processes that mostly change the shape of the earth surface and has severe environmental and economic damages. The aim of this research is modeling between geo-environmental parameters effective in gully erosion and gully occurrence in the study area and gully erosion susceptibility mapping using evidential belief function (EBF) data driven model in toroud watershed that has high susceptibility to gully erosion. At first, a gully erosion inventory map is prepared, using extensive field surveys and 80 gullies which have been identified, 70 percentage (56 gully location) randomly selected to modeling, while the remaining 30 percentage (24 gully location) are used to validation. In modeling, if there was high correlation among parameters, reduce accuracy of model, thus has done multi-collinearity test among independent variables. Tolerance and the variance inflation factor (VIF) are two important indexes for multi-collinearity diagnosis. Finally 15 parameters including geomorphological, geological, environmental and hydrological are selected for modeling. In evidential belief function model four relationships were calculated: belief (Bel), disbelief (Dis), uncertainty (Unc), and plausibility (Pls) and belief function are used for gully erosion susceptibility mapping. Area under the curve are used for model validation. According to results, EBF model with prediction rate (1) and success rate (0.959) had excellent accuracy and capability in identification of prone areas to gully erosion in study area. The results indicates that 21.79 percentage (90.84 km2) in study area located in high and very high susceptibility class.
mahshid souri; khaled bayazidi; ehsan zandiesfahan; javad motamedi
Abstract
Agropyron desertorum is the most important perennial grasses are semi-arid and temperate areas, which are recommended by natural resource experts to provide forage, pasture, soil stabilization and management of water resources. Awareness of the variation of rangeland species in different environmental ...
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Agropyron desertorum is the most important perennial grasses are semi-arid and temperate areas, which are recommended by natural resource experts to provide forage, pasture, soil stabilization and management of water resources. Awareness of the variation of rangeland species in different environmental conditions is one of the requirements for the reclamation, management and management of rangeland ecosystems. The aim of this study was to investigate effects of drought and contamination on the yield of Agropyron desertorum. The research on greenhouse was conducted in a factorial design based on copper oxide treatments at four levels (0, 25, 50 and 100 mg), copper Nano-oxid in 4 levels (0, 25, 50 and 100 mg) and polyethylene glycol 6000 (PEG6000) in three levels (0, -0.6 and -1/2 mpa) in 5 repeaters on Agropyron desertrorum was conducted in hydroponic greenhouses. The data measuring (biomass, shoot fresh weight, root fresh weight, during the shoot, root K, potassium shoot, chlorophyll a, chlorophyll b and all chlorophyll) by using SPSS.18 and Duncan test were analyzed. The analysis showed all the characteristics measured traits such Agropyron desertorum treated with copper oxide and copper Nano-oxid as well as their interactions in all treatments was significantly reduced compared to control. Agropyron desertorum estates in the areas where the soil has been Nano-oxid and oxides. Also, if the purpose of the cultivation of these species is provide forage for livestock in the affected areas, the cultivation of this species is not suitable and is not recommended.
Jaber Sharifi; Amrali Shahmoradi
Abstract
Vegetation changes rangelands, that usually occurs in the composition and structure of vegetation over time. On the other hand, human factors, especially rangeland management, play an important role in maintaining stability or degradation. The purpose of this study was to investigate the dynamics of ...
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Vegetation changes rangelands, that usually occurs in the composition and structure of vegetation over time. On the other hand, human factors, especially rangeland management, play an important role in maintaining stability or degradation. The purpose of this study was to investigate the dynamics of vegetation under the local management was carried out from 2008 to 1391. To do this, main vegetative stepic regions of the factors related to crown cover, density and abundance were determined by multi-year and group species, during the three transects 500 m in 30 plots (5/1 × 5/1 meter) as well as soil moisture and organic carbon were measured. The results showed that a four-year period, In the vegetation of perennial grasses, such as Festuca ovina, Alopecurus aucheri, Bromus tomentellus and Koeleria caucasica their variation was due to rainfall in the growing season, there was no significant difference between study years. In shrub cover such as Onobrychis cornuta and Astragalus aureus were significantly different between years of study due to annual precipitation fluctuations and soil moisture moisture content. In perennial forbodies, such as Scorzonera radicosa, Polygonum alpetre and Veronica orientalis were affected by precipitation seasonal and there was a significant difference between years. Changes in soil organic carbon and the process is slow. Therefore the results of the survey year to year changes in vegetation,climate changes and soil moisture also how the soil erosion condition can as an appropriate guide for the correct current methods used for management of rangeland ecosystems.
afshin sadeghirad; Hossein azarnivand; mohamad jafari; mohamadali zarechahoki
Abstract
Nowadays climate change, is the most significant threat in terms of sustainable development, particularly in developing countries. So regarding to rangeland ecosystems and their ability is a Particular attention to sequester carbon. This study aimed to assessing the carbon sequestration potential of ...
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Nowadays climate change, is the most significant threat in terms of sustainable development, particularly in developing countries. So regarding to rangeland ecosystems and their ability is a Particular attention to sequester carbon. This study aimed to assessing the carbon sequestration potential of natural and planted ranges through selected three species S. barbata, S.rigida and A.canescens. sampling from vegetation and soil have done along three 200 meters parallel transects by Systematic - random method. So that were taken 30 vegetable and 36 soil samples which were measured the organic carbon plants samples and some physical and chemical properties of soil In the laboratory. Then, by multiplying the amount of organic carbon in soil bulk density, was calculated total weight of carbon sequestration in soil depth. The results showed that among the three sites, the depth first of the soil, the amount of silt, sand, organic carbon, PH and EC (electrical conductivity) and In the second depth of the soil, the amount of silt, organic carbon, nitrogen, PH and EC there was a significant difference at 5% level. The comparison of carbon sequestration to the total habitat by Duncan's test showed that all three species were significantly different from each other at 5% level, So that the greatest amount of carbon stored is in the A.canescens planting of rangeland (39/84 ton/ ha) and the lowest Natural rangeland S.rigida (36/24 ton/ha), However the Natural range S.barbata was intermediate between both other species (31/34 ton/hac).
hosain kaffash; mostafa taleshi; hosain rahimi
Abstract
Government policies and investments that have been made in the past few decades with the aim of sustaining rural settlements have not reached desirable results, but today, most villages have adapted and adapted to environmental crises such as water crisis, adaptability and less agitation. In this research, ...
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Government policies and investments that have been made in the past few decades with the aim of sustaining rural settlements have not reached desirable results, but today, most villages have adapted and adapted to environmental crises such as water crisis, adaptability and less agitation. In this research, policy and government investments in arid areas have been investigated and by means of quantitative and quantitative analysis, the effect of the above measures on reducing the water crisis is explained. The research is a descriptive and inferential goal from a strategic point of view, from surveying strategy, from the point of view of the causal nature and from the point of view of the method of collecting field data and documentation. The statistical population is 4626 rural households. The sample size with the Cochran formula is 354 people. In data analysis, the structural equation modeling model with partial least squares method and Smart PLS2 software were used to examine the conceptual model. The internal structure of the questionnaire and the convergent validity were determined using the results of the verifiable factor analysis and the mean of variance explained by AVE. For this purpose, standardized load factors were calculated and the AVE index was calculated for all items and variables. The test of assumptions proves that limited government actions in the past 10 years have had no effect on the reduction of the water crisis in the research area and the process of instability of rural settlements has not stopped.
javad zahiri; hadis shahrokhi; Ahmad Jafari
Abstract
Suspended sediment load estimation is one of the most important and complicated debates on sediment transport and river engineering. Therefore, the variety of methods developed to estimate suspended sediment load in rivers. According to the empirical nature of these methods, the results have low accuracy ...
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Suspended sediment load estimation is one of the most important and complicated debates on sediment transport and river engineering. Therefore, the variety of methods developed to estimate suspended sediment load in rivers. According to the empirical nature of these methods, the results have low accuracy and vary so widely from one method to another. Recently, with advances in computer science, various algorithms such as tree based methods have been developed. In this study, sediment rating curve method along with new algorithms such as M5 and Genetic Programing (GP) are used for estimating suspended sediment load in rivers. Flow and sediment discharge data at five hydrometric stations, Behbahan and Cham Nezam on Maroon River, Jow Kanak on Allah River and Moshrageh and Shadegan on Jarahi River are used in present study. The efficiency of tree models, in all stations, was greater than sediment rating curve method, and the RMSE performance of M5 method is 7 to 41 percent superior to sediment rating curve method. The results of this study indicate the close proximity of both M5 and GP efficiency, which according to the simple and conceptual structure of M5, this method is proposed to estimate suspended sediment load in river streams.
1 1; 1 1
Abstract
Stochastic climate generators are used in many studies such as application of hydrologic, environmental management and assessment of agriculture risk. These studies require for assessment of risk to long term series from meteorological data. Considering of climate data limitation at large area in Iran ...
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Stochastic climate generators are used in many studies such as application of hydrologic, environmental management and assessment of agriculture risk. These studies require for assessment of risk to long term series from meteorological data. Considering of climate data limitation at large area in Iran and short term of data, it is necessary using of climate generator and evaluation of precision and accuracy. Therefore in this study have been evaluated the efficiency of three generators namely CLIGEN, ClimGem and LARS-WG in sangeneh and Zidasht station with different climate condition. Statistical test of t (t paired) have been used to compare the differences between observed and production weather data such as yearly and monthly precipitation amount, yearly number of wet day, yearly average of max. and min. temperature. The obtained results show that CLIGEN generator have the better efficiency than two others generator in two stations and five considered variables. ClimGen haven't had the good efficiency in two stations. Also, LARS-WG generator have had the good efficiency in Zidasht station, but it's efficiency have had the less efficiency for product of temperature variables in Snganeh station. Generally, the obtained results show that the efficiency of these generators is better in mild climate than arid and semi-arid climate.
Fatemeh Einloo; Ali Salajegheh; Arash Malekian; Mohsen Ahadnejad
Abstract
Urbanization has led to development the impervious surfaces and subsequently changes in urban hydrology. The aim of this study is investigate the effect of land use change and urbanization on the changes of runoff peak discharge in Zanjan City Watershed, Iran. In order to, Landsat Thematic Mapper (TM) ...
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Urbanization has led to development the impervious surfaces and subsequently changes in urban hydrology. The aim of this study is investigate the effect of land use change and urbanization on the changes of runoff peak discharge in Zanjan City Watershed, Iran. In order to, Landsat Thematic Mapper (TM) images and Aerial photos of 1956, 2000 and 2012 has been processed by using IDRISI Selva and Geographic Information System software and land use maps prepared in six land use class and the trend of land use changes and urbanization determined. To analysis the hydraulic and hydrology behavior of three periods of land use changes and urbanization on the changes of runoff peak discharge, Stormwater Management Model (SWMM) was used. After the SWMM model calibration based on observation rainfall-runoff events, the results of model calibration and verification, confirmed the accuracy of the model simulation. The results of land use change and urbanization trend of Zanjan City Watershed show that urban areas in 2012 compared to 2000 and 1956, respectively, has increase 22.59 and 923.88 percent and in 2000 compared to 1956 has been increased 543.06 percent. The results of SWMM model show that land use change and urban development has led to increase the runoff peak discharge, so that the average change in runoff peak discharge show that it increase in 2012 compared to 1956 and 2000, respectively, 96.85 and 475.52 percent and in 2000 compared to 1956, 194.288 percent increase in average of runoff peak discharge is observed.
Mohammad Reza Ekhtesasi; mohammad sefid; Ali Morovati Sharif Abadi
Abstract
Zonation of quality of drinking water sources is necessary for Water Management in Arid and Hyper Arid areas. In this research, spatial variations of quality characteristics of water (EC, Na, K, Mg, Ca, NO3, SO4, Alkalinity, Cl, TH and TDS were investigated in one-year period (2015-2016) based on the ...
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Zonation of quality of drinking water sources is necessary for Water Management in Arid and Hyper Arid areas. In this research, spatial variations of quality characteristics of water (EC, Na, K, Mg, Ca, NO3, SO4, Alkalinity, Cl, TH and TDS were investigated in one-year period (2015-2016) based on the data collected from 55 drinking deep wells of Yazd Plain. In order to evaluate and select the best method of interpolation was used Simple kriging, Ordinary kriging and Inverse Distance Weighted and RMSE. Zoning maps showed that groundwater of Charkhab and Yazdgerd respectively are in the Southeast and Northwest of study area, which are affected by flow of the Mehriz and Taft river, that are higher quality than the middle part of study area.The changes in the main indicators of quality such as TDS are from less than 500 to more than 2500 mg/lit and EC from less than 700 to more than 3,500 micromhos/cm that this achievement reflects the need for utilization management and preparation of drinking water with best quality to enter the network. Also the wells in the center of study area such as 16 Silo, 12 Dehno, 13 Dehno and 24 Dehno in terms of quality parameters such as TDS, TH, EC and Cl have more than double the national standard limit, that is recommended to remove them or adjustment operation of wells in drinking water network.
Mehdi Ghorbani; leila avazpour; sadegh heydari
Abstract
Governance of natural resources is currently hampered by abundant challenges. The way out of this dead-end is injecting kind of capital derived from people per se i.e. social capital which is unfortunately the missing part of collaborative governance of natural resources. The present study was an attempt ...
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Governance of natural resources is currently hampered by abundant challenges. The way out of this dead-end is injecting kind of capital derived from people per se i.e. social capital which is unfortunately the missing part of collaborative governance of natural resources. The present study was an attempt to evaluate the structural characteristics of out-group social capital in local beneficiaries’ network, in keeping with natural resource governance. It was conducted under the international RFLDL project in four regions of South Khorasan province. To measure the structural features of out-group social capital of local beneficiaries of each region, network analysis questionnaires were applied and there was a direct interview with network actors (heads of rural development micro committees) and their trust an participation ties were investigated. It was found out that post-RFLDL project implementation, trust and participation level or in other words the out-group social capital of each four regions escalated among heads of rural development micro committees. It can be asserted that natural resource governance will not actualize utterly and natural resource management will come to halt in a limited and stagnant framework, void of the participation of communities, where a mono-lateral power is exerted over decision-making around natural resource issues unless social capital develops among actors and they participate actively in this process.
Ataolah Kavian; 1 1; 1 1; 1 1; 1 1; 1 1; 1 1
Abstract
Small and portable rainfall simulators are essential tools in study of soil erosion and surface hydrology and it provide to repeat natural rainfall characteristics. In addition to the introduction of this device, calibration tests were performed including nozzles discharge evaluation, uniformity test ...
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Small and portable rainfall simulators are essential tools in study of soil erosion and surface hydrology and it provide to repeat natural rainfall characteristics. In addition to the introduction of this device, calibration tests were performed including nozzles discharge evaluation, uniformity test over the plots and raindrop size distribution. The results of nozzles discharge calibration showed that two nozzles discharge at 20, 40, 60 and 80 KPa pressure are similar and there isn't any significant difference between them. To achieve the optimum uniformity of simulated rainfall over the plot uniformity test was performed with changing nozzle distance (50, 60 and 70 cm) and oscillation of nozzles (30, 45 and 60 degrees) at constant operational pressure of 60 KPa. The results showed that the uniformity coefficient at 2m2 plot obtained from 57% to 61% and rainfall intensity changes from 48 to 101 mm/hr. The results of high velocity photography revealed median diameter of raindrop as 2.4 to 2.6 mm.
Hamidreza Koohbanani; Mohammadreza Yazdani
Abstract
Approximating the evapotranspiration is one of the most difficult parts of the hydrologic cycle. However it plays a very important role in the water balance equation. In the present study, the SEBAL model has been revalidated as an approved and successful approach for calculating the evapotranspiration. ...
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Approximating the evapotranspiration is one of the most difficult parts of the hydrologic cycle. However it plays a very important role in the water balance equation. In the present study, the SEBAL model has been revalidated as an approved and successful approach for calculating the evapotranspiration. In SEBAL model, the evapotranspiration is the unknown value in the equation of surface energy balance for the land surface. Considering the differences in the calibration of LDCM compared to the previous generations of the Landsat satellite, the SEBAL model was reexamined in some especial parts. In order to test of the usefulness of SEBAL model over LDCM, the measured values was compared with the values obtained via Penman-Monteith method in 20 different days. ET estimated by SEBAL compared with PM ET was found to correlate significantly as R2 (0.7) with the correlation coefficient of 0.83. Hence the results of this analysis outline that actual evapotranspiration data can be calculated and mapped in large areas and with high reliability without the need for meteorological information periodically and regularly.
TAYYEBEH MESBAHZADEH; ali azareh; Elham Rafiiei sardooi; Fateme FarzanePei
Abstract
Soil moisture, as the soil hydrologic parameters, can be affected by soil temperature and controls various hydrological processes. Given the importance of this issue, in this study, the efficiency of artificial neural network was studied to simulate soil temperature at 5- 100 cm depth. Recorded meteorological ...
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Soil moisture, as the soil hydrologic parameters, can be affected by soil temperature and controls various hydrological processes. Given the importance of this issue, in this study, the efficiency of artificial neural network was studied to simulate soil temperature at 5- 100 cm depth. Recorded meteorological parameters in the Isfahan synoptic station were used to simulate the soil temperature at different depths. The structure of the neural network was formed with an input layer, a hidden layer and an output layer and network training was done by Levenberg–Marquardt algorithm. Also test and error was done to determine a number of suitable neurons in hidden layer. The results showed that error in both neural network and ANFIS model increases with depth increase that can be due to the weak correlation between soil temperature changes in the lower layers and climatic parameters.
