Asghar Mosleh Arani; Hamidreza Azimzadeh
Abstract
Plant cover is one of the most important factors affecting infiltration rate of water into the soil and decreasing runoff. Distribution of plants in arid and semi-arid areas is almost patchy and form different patterns. One of the fascinating patterns is ring-shaped growth pattern. Ring patterns of varying ...
Read More
Plant cover is one of the most important factors affecting infiltration rate of water into the soil and decreasing runoff. Distribution of plants in arid and semi-arid areas is almost patchy and form different patterns. One of the fascinating patterns is ring-shaped growth pattern. Ring patterns of varying size are formed by clonally reproducing grasses, sedges and even shrubs growing in resource-limited (water and nutrient) environments. Study on the role of ring pattern in infiltration rate is lacking. In this study infiltration rate was compared between ring patterns formed by Iris songarica and Scripoides holoschoenus and soil without plant cover (bare soil). Infiltration rate was measured by double ring in different time interval until infiltration was constant. Infiltration models efficiency were analyzed by calculation Nash-Sutcliffe coefficient. Result from paired T test analysis showed that infiltration rate was significantly different between two plants and also with bare soil (p
F. Daliri; H. S. Seraji; M. Kholghi
Volume 62, Issue 2 , October 2009, , Pages 247-257
Abstract
The system analysis plays an important role in natural resources, water resources and industrial engineering. In recent years, most parts of Iran like Golestan province, due to the lack of integrated river basin management, have been suffered numerous losses in variant environmental, social and economic ...
Read More
The system analysis plays an important role in natural resources, water resources and industrial engineering. In recent years, most parts of Iran like Golestan province, due to the lack of integrated river basin management, have been suffered numerous losses in variant environmental, social and economic aspects. In this paper an application of system analysis has been applied to optimal pattern of various resources in Gharmabdasht Watershed situated in Golesten province, Iran. To achieve an optimal allocation of natural resources in this area, firstly a linear programming algorithm has been used to maximize the benefits. Then its results have been compared with an optimal allocation of resources using a goal programming. This comparison shows if a single objective optimization (LP) be formulated correctly, it can be that the proposed pattern, has been acceptable outputs in which be compared to goal programming(GP). The allocation natural resources based on LP method, in addition to reducing %10 of sediment from admissible amount effected by safety flood abatement criterion, has also maximized the beneficiary incoming with %5 plus needful along satisfied all of the goals.
Asghar Zare Chahouki; Ali Salajegheh; Mohammad Mahdavi; Sharam Khalighi; Said Asadi
Abstract
A flow-duration curve (FDC) illustrates the relationship between the frequency and magnitude of streamflow. Applications of FDC are of interest for many hydrological problems related to hydropower generation, river and reservoir sedimentation, water quality assessment, water-use assessment, water allocation ...
Read More
A flow-duration curve (FDC) illustrates the relationship between the frequency and magnitude of streamflow. Applications of FDC are of interest for many hydrological problems related to hydropower generation, river and reservoir sedimentation, water quality assessment, water-use assessment, water allocation and habitat suitability. This study was carried out in 11 selected watersheds with common characteristics such as the 20 years period, the minimum land use change and similar annual water volume through all watersheds in 3 province of: Yazd, Semnan and Markazi which are located in central zone of Iran to regional flow duration curve. It was extracted Q5, Q10, Q20, Q30, Q40, Q50, Q60, Q70, Q80 and Q90 from 11 Hygrometric stations as a dependent variable were derived from flow duration curve. The flow duration curve is regionalized by using morphoclimatic characteristics of the drainage basin. Using multiple regression techniques, the geographic variation of each parameter of the best fitted flow duration model is explained in terms of the drainage area, length of longest flow, Stream slope, mean annual areal precipitation, course from the divide of the basin to the site of interest. The regionalized nonlinear regression equations are successfully used to flow duration curves at other locations within the hydrologically homogeneous regions of center of Iran. A cross-validation Nash–Sutcliffe Efficiency procedure was used to evaluate best fitting of the regional model in ungauged watershed.
Reyhane Azimi; Mohammad Khajeh Hosseini; Farnosh Falahpor
Abstract
Bromus kopetdaghensis is one of perennial plants of Poaceae family and it is important in biodiversity of arid and semi arid grasslands of Iran. This experiment was conducted as a completely randomized design with 4 replications in laboratory of faculty of Agriculture, Ferdowsi University of Mashhad, ...
Read More
Bromus kopetdaghensis is one of perennial plants of Poaceae family and it is important in biodiversity of arid and semi arid grasslands of Iran. This experiment was conducted as a completely randomized design with 4 replications in laboratory of faculty of Agriculture, Ferdowsi University of Mashhad, Iran.Treatments were different constant temperature of 5, 10, 15, 20, 25, 30, 35, and 40°C with 4 replications and in each replication 25 seeds were used. The results showed significant effects on different germination features of Bromus kopetdaghensis. The lowest germination rate (with 2.26 seed per day) was obtained at 5°C and the highest (with 11.39 seed per day) at 30°C. The maximum and minimum length of caulicle was obtained at 35°C (with 9.41cm) and 10°C (with 2.48cm), respectively. Maximum length of radical was also observed at 35°C (with 9.62cm) and minimum length of radical was observed at 10 and 20°C, without significant different with 3.63 and 3.48 cm. Based on the regression analysis between rate of germination and temperature the cardinal temperature of maximum, optimum, and minimum were obtained in the range of 0.71-4.25, 24-30.36 and 41.01-45.48, respectively.
Fatemeh Einloo; Mohammad Reza Ekhtesasi; Mehdi Ghorbani; Parviz Abdinejad; Reza Anjomshoaa
Abstract
One of the integrated water resources management requirements based on participatory management planning is identification and analysis of key stakeholders. Identifying structural aspects of organizational stakeholder's network can be evaluated using social network analysis and their position and role ...
Read More
One of the integrated water resources management requirements based on participatory management planning is identification and analysis of key stakeholders. Identifying structural aspects of organizational stakeholder's network can be evaluated using social network analysis and their position and role for inter-organizational integration and coordination in water resources management can be determined. In this study, using social network analysis method, stakeholders related to participatory governance of Abhar plain water resources, including 20 organizational stakeholders were analyzed and policy indicators were evaluated at the level of the network of organizational stakeholders. Indices of density, size, reciprocity, transitivity, centralization and geodesic distance in network of relationships at the macro level, core-peripheral index in the middle scale and centrality indicators at the micro scale of network were examined. Rate of network density index is moderate and according to index of reciprocity, moderate amount of bilateral and reciprocal relations among organizational actors, cohesion and organizational capital are assessed as moderate. According to transitivity index, stability and balance of information exchange network is low. Analysis of core-periphery index of stakeholder's network shows a higher density of links and greater organizational cohesion among central organizations compared to peripheral subgroup and amount of information exchange between central and peripheral subgroups was evaluated as moderate. Based on centrality indicators, geometric position of each actor in network was determined. For decision-making, planning, policy-making and participatory governance of water resources in Abhar Plain, key and effective organizations and political forces, as well as organizations with low power and marginalized, were identified.
Bita Shiravi; Ali Golkarian; Ali Abotalebi pirnaeemi
Abstract
Check dams, are small dams in the watershed. These dams are constructed in susceptible areas to erosion due to reduce of flow velocity and erosion, control of sediment and flood in upstream of reservoir dams. These structures are made using wood, stone and cement, and Gabion. These structures change ...
Read More
Check dams, are small dams in the watershed. These dams are constructed in susceptible areas to erosion due to reduce of flow velocity and erosion, control of sediment and flood in upstream of reservoir dams. These structures are made using wood, stone and cement, and Gabion. These structures change the hydrological response of the watershed by reducing flow velocity, the channel slope and storage of flow.
Analyzed the effects of these dams before making can be deciding on the correct and efficient implementation of the project as well as better management in order to achieve various objectives effectively. Since the constructions of these dams are effective on flood behavior, this research aims to impact of check dams on time of concentration and reduction of flood peak discharge in the Gash watershed. In this research are used from Puls method for flood routing in reservoir and Muskingum method for flood routing in river due to evaluate the impact of dams, and also flood hydrograph with 25 to 100 year return period was simulated the situation before and after construction of dams. The results showed that the proposed check dams are reduced peak of flow between 75 to 97 percent and flood volume from 73 to 98 percent that shows the positive effects of the construction of these dams in reducing the peak of flow and flood volume. In addition, in different return period with increasing peak of flow and flood volume, reservoir role in reducing peak of flood discharge and flood volume will be decreased. Also time of concentration will be increased between 0.26 to 0.98 hours by Construction of check dams.
Mohammad Pichand; Ghasem Ali Dianati Tilaki; Ehsan Sadati
Abstract
To evaluate the effects of hydropriming and drought stress on germination traits of cymbopogon olivieri the experimental design was two factors factorial arranged in a completely randomized design, with four replications and 50 seeds per replicate. The first factor was hydropriming (in four levels), ...
Read More
To evaluate the effects of hydropriming and drought stress on germination traits of cymbopogon olivieri the experimental design was two factors factorial arranged in a completely randomized design, with four replications and 50 seeds per replicate. The first factor was hydropriming (in four levels), the second, polyethylene glycol 6000 (in four levels), in laboratory conditions. That data were analyzed using spss software. The difference between the means was compared using duncan test (p<0.05). ANOVA Results indicated that the interaction between hydropriming time treatment and polyethylene glycol treatment caused significant differences in germination rate, shoot length, shoot wet and dry weight (P<0.01) and vigor index (P<0.05 ). But it caused no significant differences in parameters of percentage of germination, average germination time, root length, root wet and dry weight. The highest percentage of germination was related to the treatment by -4 bar PEG and without priming (control). The lowest percentage of germination was resulted under hydropriming in 48h and treatment by -8 bar polyethylen glycol respectively 49 and 14 percent. The highest rate of germination was related to the treatment by -8 bar PEG and hydropriming in 48h. Also seeds didn’t germinated in -16 bar of PEG in all hydropriming times. The results showed that the treatments by -4 and -8 bar PEG during 48 and 72 hours hydropriming caused the most positive effects on seed germination percentage, germination rate, vigor index, root length, shoot length of cymbopogon olivieri seeds.
ali rezazadeh joudi; Mohammad Taghi Sattari
Abstract
Estimation of suspended sediment load or specifying the damages incured as a result of inattention to such estimation is one of the most important and fundamental challenges in river engineering and sediment transport studies. Given the importance and role of sediment in the design and maintenance of ...
Read More
Estimation of suspended sediment load or specifying the damages incured as a result of inattention to such estimation is one of the most important and fundamental challenges in river engineering and sediment transport studies. Given the importance and role of sediment in the design and maintenance of hydraulic structures such as dams, as well its significance in planning for efficient tilization of downstream river and also conservation of nutrients at the upstream of river, many attempts have been made to estimate suspended sediment load of rivers and numerical methods have been developed in this regard. But due to the high cost of most procedures or lack of adequate precision in most common experimental methods, a new method is needed that can estimate suspended sediment load with the greatest possible precision. In this study, the amount of suspended sediment load of Lighvan River has been estimated through support vector regression and k-Nearest neighbor methods. Results indicated the appropriateness of both data mining techniques applied in this study. Among examined methods in this study, the support vector regression method predicted the amount of suspended sediment load in LighvanChay River with representing evaluation indexes such as (CC=0.959, RMSE=43.547(ton/day)) more accurately than K-nearest neighbor method
Molouk Royan; Adel Sepehri; Abdolrasoul Salman Mahini
Abstract
Remote sensing and aerial photographs are used to produce medium to small scale images. However, for detailed information especially to estimate rangeland vegetation canopy cover there is a need to larger scale images. It is therefore necessary to study the technical applicability of different devices ...
Read More
Remote sensing and aerial photographs are used to produce medium to small scale images. However, for detailed information especially to estimate rangeland vegetation canopy cover there is a need to larger scale images. It is therefore necessary to study the technical applicability of different devices such as short range light airplanes, kites, gliders and balloons. In this research, we focused on suitable flight height for rangeland vegetation canopy cover estimation using large scale balloon images in Incheh Broon area where we conducted field tests in September 2010. The balloons ascended to heights of 5, 10, 25, 50 and 100 m and higher. Using the taken images, vegetation canopy covers were estimated and compared with those obtained from field measurements. Results show that there is no significant difference between field and image estimation of canopy cover for heights lower than 100 m. We therefore suggest using balloon images acquired from up to 100 m height for estimating rangeland vegetation canopy cover.
seyed akbar javadi; alireza khanarmooyi; Mohammad Jafari
Abstract
The relationship between vegetation and soil properties in Khojier National park, located in Tehran province was investigated. For this purpose, vegetation data was recorded in each plot, based along 3 tansects in each vegetation type. Minimal area method was used for plot size. Density and vegetatin ...
Read More
The relationship between vegetation and soil properties in Khojier National park, located in Tehran province was investigated. For this purpose, vegetation data was recorded in each plot, based along 3 tansects in each vegetation type. Minimal area method was used for plot size. Density and vegetatin cover were determined. TWINSPAN and DCA tests were used to classify vegetation. Soil sample was taken from 0-20cm of soil depth then transferred to laboratory and prepared for analysis including soil texture, percentage of CaCo3, CaSo4, and pH, EC, P, Ca, Ma and N. For analysis of soil properties in relation to vegetation changes, a multivariate analysis method such as canonical correspondence analysis (CCA) was used. These analyzes were conducted using PC-ORD software. Results showed a significant correlation between vegetation and environmental factors. The most important soil properties affecting on vegetation types were gravel, clay, silt, sand, caso4, caco3, pH, EC, K and elevation. Statistical analysis of the results showed that the vegetation types had a significant difference in terms of percentage of Gravel, CaCo3, CaSo4, Sand, Clay.The most important soil properties affecting on vegetation types were gravel, clay, silt, sand, caso4, caco3, pH, EC, K and the height above sea level. Statistical analysis of the results showed that the vegetation types had a significant difference in view of percentage of Gravel, CaCo3, CaSo4, Sand, Clay.
R Tahmaseb; F . Sharifi; F Kaveh; A Tavassoli
Volume 63, Issue 3 , December 2010, , Pages 359-373
Abstract
One of the major sectors of water loss is the loss of rain runoff. Kirkby (2001) the Effect of soil surface characteristics in the production of runoff in time and space scales concluded that soil properties such as undulating, soil texture and structure on the amount and spatial pattern of runoff are ...
Read More
One of the major sectors of water loss is the loss of rain runoff. Kirkby (2001) the Effect of soil surface characteristics in the production of runoff in time and space scales concluded that soil properties such as undulating, soil texture and structure on the amount and spatial pattern of runoff are effective. In this research that was conducted in the Latian watershed, twenty experimental plot Manufacturer runoff collected at the end they were constructed Bankettes longitudinal dimension equal to the width of runoff plot, poster collection, depth 0.5 meter and width of 0.5 meter was constructed. Depth of rainfall runoff from natural and 12 each with artificial rainfall intensity rainfall simulator with 8 mm to 42 mm per hour was established, was measured. Since the end Bankettes within plots were covered with plastic, all collected runoff was measured on it. The plastic cover was pulled out of water completely penetrating Bankette. After 24 hours on Bankette collected water depth was measured so that how deep the penetration has. After the plastic cover was created to prepare for the next runoff is measured. Part of the rainwater Collected in a barrel with a volume of 220 liter were stored on the first of the spring was covered with a plastic cover to prevent evaporation of collected water for limited irrigation water supply in June to 30 July to 15 of 62 mm were used and in forage maize plots nine branches were planted SC704. The results showed that compared with the yield ratios of 1:1, 2:1 and 3:1 (ratio of surface runoff collected rain Manufacturer of level of corn planted) yield of forage corn, respectively 9.6, 22.6 and 28.8 T.ha respectively. Whereas in the control treatment, there was no water limitation and the rate of 41.5 T.ha of forage maize yield was, The total water used in the three above treatments, respectively 616, 696 and 776 mm was. (In addition to direct rain water collected from runoff) and supplementary irrigation water depths in all three treatments was 62 mm. Thus yield respectively 23, 55 and 69 percent compared to the control (grown with full irrigation) has been. In this research the effect of vegetation and soil in runoff amounts were compared.
Mohammad Ali Zare Chahouki; mahbobe abbasi
Abstract
Rheum ribes species is one of the important medicinal plants in the world. In this study were used maximum entropy method (Maxent) and the MAXENT software to this prediction habitat map. Measure environmental variables was soil variables including gravel percentage, pH, electrical conductivity, percent ...
Read More
Rheum ribes species is one of the important medicinal plants in the world. In this study were used maximum entropy method (Maxent) and the MAXENT software to this prediction habitat map. Measure environmental variables was soil variables including gravel percentage, pH, electrical conductivity, percent lime, gypsum, organic matter, soluble salts (Ca+, Na+, K+, Mg2+, CL, HCO3, SM and SO2), sand, clay and silt and variable topography (slope, aspect and elevation) and rainfall variable. Those were effective variables on the presence of species. The model classification accuracy using the area under the curve (AUC) was 95% (good Level), and kappa coefficient was obtained 0.92 that measuring from the agreement of prediction maps with ground truth, which is at a high level. The results of this study showed that the habitat of this species is in the soils with low pH (less than 8), clay Low (less than 40%), coarse texture and organic matter more than 4.0 percent. And the presence of this species has inverse relationship with a pH of both the depth and the clay first depth and with has directly relationship to organic matter of both depths.
Farnoosh zareii; Hamed Joneidi; Parviz karami
Abstract
This research was carried out to evaluate the effect of rangeland conversion to afforestation with Cupressuss arizonica and Celtic caucasica on soil carbon emission. In order to determine the rate of carbon and carbon dioxide emission by tele-alkaline method with a stacking chamber, monthly was performed ...
Read More
This research was carried out to evaluate the effect of rangeland conversion to afforestation with Cupressuss arizonica and Celtic caucasica on soil carbon emission. In order to determine the rate of carbon and carbon dioxide emission by tele-alkaline method with a stacking chamber, monthly was performed with 5 replicates per treatment and for one year. The analysis of carbon dioxide emission was done by one way ANOVA and Duncan's test. The results showed that the rate of carbon emission in Cupressus arizonica, Celtise caucasica and rangeland treatments was 110.49, 104.92 and 91.22 kg/ha/month, respectively and rate of carbon dioxide emission was 406.78, 384.71 and 48.433 kg/ha/month, respectively. The rate of carbon and carbon dioxide emission in 12 months in the area under consideration was also significant at 5% error level, have been with the highest carbon and carbon dioxide emissions in October and the lowest in August. In terms of seasonal distribution, the rate of carbon and carbon dioxide emission in rangeland and Cupressus arizonica treatments was not significant, but in the Celtise caucasica treatment was significant at 5% error level, with the highest carbon and carbon dioxide emission was in autumn, spring, winter and summer, respectively. In total, C.arizonica and C.caucasica reduced about 5/5% and 18% carbon and carbon dioxide emissions, respectively, than the adjacent rangeland did. Therefore, we can reduce the rate of carbon emission by appropriate management plans such as proper land use change.
Jalal Zandi; Mahmoud Habibnejad Roshan; Karim Solaimani
Abstract
Soil erosion is a serious environmental problem in Vazroud watershed, which is located in the centre of the Mazandaran Province, Iran. Unfortunately, Vazroud watershed like most Iran watersheds don’t have recorded data and erosion and sedimentation gages to research, monitor and model soil erosion ...
Read More
Soil erosion is a serious environmental problem in Vazroud watershed, which is located in the centre of the Mazandaran Province, Iran. Unfortunately, Vazroud watershed like most Iran watersheds don’t have recorded data and erosion and sedimentation gages to research, monitor and model soil erosion at large watershed. In order to assess the soil erosion risk, soil erosion modeling at the watershed scale are urgently needed to be undertaken. This study integrated the Revised Universal Soil Loss Equation (RUSLE) with a Geographic Information System (GIS) to estimate soil loss and identify the risk erosion areas in the Vazroud watershed. Multi-source (map-, space- and ground-based) datasets were used to obtain factors of RUSLE, and an integrated analysis was carried out in raster format of GIS and it was classified into five categories ranging from minimal risk to extreme erosion risk. Extensive field observations verify soil erosion risk map and total accuracy (90%) obtained. The soil erosion map was linked to land use, elevation and slope maps to explore the relationship between soil erosion and environmental factors and identify the areas of soil erosion risk. The slopes between 25 to 45 degree, the altitudes between 1180 to 2180 from sea level and bare lands have the high and extreme erosion risk in this study area. The results allow decision makers to implement management strategies to prioritization area and soil erosion reduction in Vazroud watershed. The integrated approach presented is relatively easy, fast, and straightforward, showing good potential for successful application in other areas.
ali shahbazi; Shahram khaliqi sygarodi; Arash Malekian; Ali Salajegheh
Abstract
In order to decrease the risks associated with the management of urban watersheds, the use of proper methods is an essential task to estimate the runoff with a high degree of confidence. Time of concentration is one of factors that impacts on peak discharge and runoff volume. The objective of this study ...
Read More
In order to decrease the risks associated with the management of urban watersheds, the use of proper methods is an essential task to estimate the runoff with a high degree of confidence. Time of concentration is one of factors that impacts on peak discharge and runoff volume. The objective of this study is to select the best method among the empirical formulas for estimating the time of concentration. In this study, for determination of actual time of concentration, the field method based on measuring the travel time by using floating-object method was employed. To select the best empirical formula of the time of concentration, the statistical criteria including percentage Relative Error (RE), Root Mean square error (RMSE), Average percentage Relative Error (RME), Nash - Sutcliffe criteria (NS) and determination coefficient were used. Then, differences among the estimations obtained from empirical equations were compared with the actual values. The results of this study based on comparison of the relative error in each interval showed that in the reach No. 2, empirical formulas of California, Chow, Carter and Federal Aviation, with percentage error of 2.7, 2.9, 4.4 and 4.4 have showed the best estimation, respectively. The equation proposed by Kirby with percentage error of 1 in the reach No. 3, the equation of Ventura with percentage error 8.5 in the reach No. 9 and the equation of rational hydrograph with percentage error 4.8 in the reach No. 10 have showed the best estimates. Therefore, it is recommended to use the empirical formula that has the lowest percentage of error for areas with features similar to the studied reaches. In general, the results show that only rational hydrograph method in all of the reaches has the lowest error and then provides the most proper estimates compared than others.
J. Sharifi; M. Akbarzadeh
Abstract
A major part of the rangelands of Iran are located in arid and semi-arid regions. In this climate, rainfall fluctuation is an important factor which affects vegetation and forage production. In dry years that rainfall decreases, surface vegetation and forage production is damaged. This study was conducted ...
Read More
A major part of the rangelands of Iran are located in arid and semi-arid regions. In this climate, rainfall fluctuation is an important factor which affects vegetation and forage production. In dry years that rainfall decreases, surface vegetation and forage production is damaged. This study was conducted on semi-steppic rangelands of Ardebil over nine years (1999-2007), to study of vegetation changes with rainfall fluctuation. The results showed that canopy cover of Salsola gemmascens and Noaea mucronata species was decreased but Artemisia fragrans and Kochia prostrata species were increased.Generally density of shrub species was decreased about 40% and showed a positive correlation with seasonal precipitation (fall and winter). Grass species showed different response to precipitation changes over nine years period and in general, no significant changes were observed. Stipa hohenackeriana species was affected by winter precipitation but Poa bulbosa and Cynodon dactylon were correlated with spring precipitation. Density of perennial forbs species was increased considerably (about seven times), but in dry years (2000-2002) forage production reduced. Forage production over nine years increased from 296 kg to 747 kg per hectare, which is approximately 2.5 times higher. Meanwhile, proportion of plants in classes I, II and III, were respectively, 23.1, 51.9 and 25.2 percent of forage production. Also, forage production in wet periods increased from 747 to 1968 kg per hectare which shows an increase of about seven times.
Reza Siahmansour; Hossein Arzani; Mohamad Jafari; Seyed Akbar Javadi; Ali Tavili
Abstract
Fire consider as a factor and basic management in rangeland in order to reform of composition and biological diversity that use in rangeland ecosystems. This project was established to deal with the effect of fire in the research center for rangeland. Zagheh locale where is in 35 km of north eastern ...
Read More
Fire consider as a factor and basic management in rangeland in order to reform of composition and biological diversity that use in rangeland ecosystems. This project was established to deal with the effect of fire in the research center for rangeland. Zagheh locale where is in 35 km of north eastern of Khoramabad with 1960 meters above sea level. The average comparison and analysis show that herbal forbs which use for grazing form density and average o canopy cover have significant difference at the level of %1 between fire and control area. (p < %1). This study shows that in short time, it is possible to replace perennial. The Prevailing type of grass such as Agropyron trichophorum - Bromus tomentellus and festuca ovina with annual grass like Bromus tectorum –Heteranthelium piliferum- Taeniatherum crinitum. These changes indicate perennial grasses and increased annual grasses in short time.
محمد قبایی سوق; Abolfazl Mosaedi
Abstract
Reconnaissance Drought Index (RDI) is based on fitting a Log-normal distribution to the ratio of precipitation to evapotranspiration (ETo) values in selected periods. In this index value of ETo were calculated based on mean temperature by Thorenth-Waite (Th) method. Th method, may underestimated ETo ...
Read More
Reconnaissance Drought Index (RDI) is based on fitting a Log-normal distribution to the ratio of precipitation to evapotranspiration (ETo) values in selected periods. In this index value of ETo were calculated based on mean temperature by Thorenth-Waite (Th) method. Th method, may underestimated ETo values comparing to the actual in arid and semi arid regions. The log-normal distribution may not be fitted to the ratio of precipitation to ETo values of some regions. In order to investigate the effects of these two limitations on drought situations' changes, meteorological parameters have been used during 50 years period at 8 Synoptic Stations of Iran. In the first step, the values of RDI(Th) for any stations during the mentioned time were calculated. Then, ETo values were calculated from best fitted empirical equation in any situation of lack of parameters. Subsequently RDI(select) index were established. The Kolmogorov–Smirnov (KS) test is used to assess the goodness of fitting most appropriate distribution function to the ratio of precipitation to ETo values. Then, according to equi-probability transformation the values of RDI(Th) were modified to *RDI(Th). The occurrence of different classes of drought according to RDI(select) and/or *RDI(Th) comparing to RDI(Th) showed the elimination of any mentioned limitations may leads to changing the amount of occurrence of any drought classes in RDI(Th). Hence, The RDI(Th) modified to *RDI(select) by estimating ETo values from selected method and applying appropriate distribution function to the ratio of precipitation to ETo values.
sepideh fazelian; Pejman tahmasbi; Hamzehali Shirmardi
Abstract
Endozoochory is one of the seed dispersal modes through animal’s digestive systems transmission and the increases rate germination and plant establishment. The aim of this study, investigated the relationship between seed characteristics and the passage through the digestive tract of livestock ...
Read More
Endozoochory is one of the seed dispersal modes through animal’s digestive systems transmission and the increases rate germination and plant establishment. The aim of this study, investigated the relationship between seed characteristics and the passage through the digestive tract of livestock and domestic animals (cattle, sheep and goats) in the 7 species perennial grass 8 species perennial forbs and 3 species annuals forbs in semi-steppe rangelands of Chaharmahal and Bakhtiari. The first, morphological seeds characteristics including: seed weight, length, width and shape of the seeds measured, and Seeds were fed to the livestock (animal treatments) and the excreta collected to order records germination success of plant species in a greenhouse during a four months experiment. Using multiple regression models the relationship between seed characteristics and success germination was evaluated and compared for different animals. Simple linear regression showed that the percentage of germination after passing through the digestive tract of livestock and properties measured, there is no communication and seed size, weight, length and width of the seed does not affect the animal through the gastrointestinal tract. The logarithmic regression showed that for perennial grasses between seed length and germination, exists direct relationship in all animal treatments. The results of this study showed that, there is no Correlation between morphological characteristics of seeds and passing through the digestive tract of livestock.
Hanieh Safari; Hossein Arzani; Ali Tavili
Abstract
Overgrazing and inappropriate use of Taleghan rangelands has led to poor and very poor condition for almost all vegetation types. Taking the importance of rangelands in forage production and other benefits into consideration, management of these rangelands and improving their condition seems essential. ...
Read More
Overgrazing and inappropriate use of Taleghan rangelands has led to poor and very poor condition for almost all vegetation types. Taking the importance of rangelands in forage production and other benefits into consideration, management of these rangelands and improving their condition seems essential. The present research was conducted using data integration of vegetation, condition, slope, soil, precipitation, etc. in a Geographic Information System (GIS) environment. Our study area was located in 50˚, 36َ, 43ً - 50˚, 53َ, 23ً longitude and 36˚, 5َ, 19 ً - 36˚, 19َ, 19ً latitude in the middle area of Taleghan watershed with the area of 37977 hectares. According to the results, improving methods and reforming activities could be suggested including prevention of livestock grazing (enclosure), sowing, inter seeding, broad casting and hoe sowing in areas which have poor and very poor condition (in 6621.325, 1274.381, 694.561, 1215.254 and 2368.101 hectares (areas), respectively). Such activities may improve livestock grazing management as well as watershed conditions, wildlife habitat or other similar purposes.
mehdi bashiri; Seyede Maedeh Kavousi Davoudi
Abstract
The soil erosion affects watershed health and lead to different negative consequences.Marl is an erosion sensitive rock that due to its special physicochemical characteristics,establishment of vegetation on it is difficult,so,it needs to management.One of the soil improvement methods is dynamic compaction,which ...
Read More
The soil erosion affects watershed health and lead to different negative consequences.Marl is an erosion sensitive rock that due to its special physicochemical characteristics,establishment of vegetation on it is difficult,so,it needs to management.One of the soil improvement methods is dynamic compaction,which applies using devices such as rollers.Also,adding pozzolan is another method for soil improvement to modify its physical and mechanical properties.Because the pozzolan in the presence of water,show adhesive properties in a stable and non-solvent form.Therefore,this study tried to evaluate the roles of soil compaction(using rollers having weights of 0,20,25,30and35Kgs)and adding natural pozzolan(in values of 0,50,100,150and200g/m2)in the taftan-pumice type on marl stabilization in Islam-Qaleh region of Razavi-Khorasan.A factorial experimental design done with3replications and totally75field plots with an area equal to30*30centimeters exposed to a rainfall with a10minutes duration and0/8Mm per minute intensity with a slope of15/5°.The results of statistical analysis in the95%confidence level showed that considering runoff,sediment load and sediment concentration variables together,the main effects of soil compaction and pozzolan treatments are significant(sig.=0/000)but their interaction effect isn’t significant(sig.=0/780).Soil compaction treatment has an increasing and significant effect(sig.=0/000)on runoff and sediment production. But the pozzolan treatment showed decreasing and significant effect (sig.=0/000) on sediment and no significant effect (sig.=0/709) on runoff. Also, the interaction effect of 2 treatments on runoff and sediment was not significant. Therefore, the soil compaction due to degradation of surface sealing and marls structure is not suitable, but according to low price and availability of natural pozzolan, for marls stabilization operations, is suggested as an economic and appropriate option.
Jaber Sharifi; Ali Ashraf Jafari; Yones Rostamikia
Abstract
Preference evaluation of four species of perennial forage grasses including Alopecurus textilis L., Festuca ovina L. and F. sulcata L. and Agropyron trichophorum. In order to use for improvement and restoration of rangelands, seeds of species were collected from of Ardebil province. After seed germination ...
Read More
Preference evaluation of four species of perennial forage grasses including Alopecurus textilis L., Festuca ovina L. and F. sulcata L. and Agropyron trichophorum. In order to use for improvement and restoration of rangelands, seeds of species were collected from of Ardebil province. After seed germination test and preparing of seed bed. This eyperiment was done based on Randomized completely block design with 3 replicates in dryland conditions from 2010 -2014 in Ardabil station. After plants establishment and end of growing, crown cover Total height, seedling vigority, forage and seed production. Analysis variance of data was done using SAS software and the mean comparison with Duncan method at 5% level. The results showed that, the species in term of studied traits, had significant difference exept survival, The highest height, crown cover and forage production. Be longes to Agropyron trichophorum, The highest seedling vigority belodes to Agropyron trichophorum and Festuca sulcata finally, Therefore these con be used in improvement and developmend procces of pasture in arid and semi arid region.
mahbube hoseini; Ali Golkarian
Abstract
Resource management governing as one of the most valuable nature resource of watersheds with the involvement of local beneficiary to participatory management of water resources, one of the requirements of the water security program. So we considered social network analysis as an approach to analyzing ...
Read More
Resource management governing as one of the most valuable nature resource of watersheds with the involvement of local beneficiary to participatory management of water resources, one of the requirements of the water security program. So we considered social network analysis as an approach to analyzing the relationship between local stakeholders for sustainable management of water resources. The purpose of this study is study social network of local stakeholders using social network analysis in watershed of Kharve Olya of Neyshabur city. This study has been made based on trust and participant links and using quantitative and mathematical indicators in network macro-level (density, concentration, links reciprocity, transferability of links, the average geodesic distance). The results show that social capital degree based on trust and participant links was strong and stability and balance of network is evaluated at the upper limit that indicates a high level of mutual trust and participant among the local stakeholders. Also the correlation between trust and participant links based on QAP index was 66% and upward average. Results of mean geodesic distance index based on trust and participant link trust indicate trust and participant flow rate is from moderate to high degree. The results can be argued that high levels of social capital and unity among people lead to increase trust and participant flow rate among stakeholders so we can accomplish successful governing of water resources at the less expense and time.
Saeide Heydari; Ali Akbar Mehrabi; Mohsen Mohseni Saravi; Sakine Saedi
Abstract
The concept of land use transition highlights that land use change is non-linear and is associated with other societal and biophysical system changes. Changes in human systems has resulted in changes in the natural system such as changes in land use. Land use change causes not only environmental factors ...
Read More
The concept of land use transition highlights that land use change is non-linear and is associated with other societal and biophysical system changes. Changes in human systems has resulted in changes in the natural system such as changes in land use. Land use change causes not only environmental factors like geography and topography are important, but social factors examined such as population growth or decline as well as changes in land use is a mix of economic, social and physical problems. Human societies and their environment, such as feedback, change, uncertainty and adaptation of interaction is social and biophysical changes associated with land use change is non-linear. Changes in human systems with natural systems, such as changes in land use will change. Landuse change causes not only environmental factors like geography and topography should not be involved in social factors such as population growth or decline as well as changes in land use is a mix of economic, social and physical problems. Migration impacts on economic activity seriously and may be initiate land use changes. this study was conducted To analyze the effects of Taleghan dam construction on developments in a human population and land use change analysis in a natural system,In general it can be suggested that in the years before the Taleghan dam, the area's population has been decreasing And pasture lands in the lower level of the population is in decline, but after the dam construction the lands become values in the area and seasonal population increases.
valiollah Raufirad; Qodratollah Heidari; Hossein Azadi; Jamshid Ghorbani
Abstract
The purpose of this study was to assess socio-economic vulnerability in lowland rangelands of Aran-v-Bidgol County. Accordingly, the most important socio-economic indices were identified using literature review. The sample size was calculated based on Cochran’s formula. Data was collected using ...
Read More
The purpose of this study was to assess socio-economic vulnerability in lowland rangelands of Aran-v-Bidgol County. Accordingly, the most important socio-economic indices were identified using literature review. The sample size was calculated based on Cochran’s formula. Data was collected using a researcher-made questionnaire. A panel of experts and Cronbach’s alpha coefficient approved respectively the content validity and reliability of the questionnaire. Me-Bar and Valdez's vulnerability formula was applied to assess the socio-economic vulnerability. Results showed that “presence of experts in rangelands”, “local problems and the collapse of past utilization systems” and “number of rangeland users” were the most important indices of social vulnerability. Findings further indicated that “life expenses of rangeland users”, “number of livestock of rangeland users”, “economic status of rangeland users”, “livestock type” and “increasing prices” are the most important indices of economic vulnerability. The results also identified that more accuracy can be obtained to assess rangelands vulnerability by integrating social and economic factors at local scale. Therefore, policy-makers and rangeland managers and practitioners should pay more attention to socioeconomic factors at local scales to sustainable rangeland management.
