Yahya Parvizi
Abstract
All worldwide studies verifies global phenomenon of climate change caused by the greenhouse effect of carbon emissions on this planet. Carbon sequestration in terrestrial ecosystem is a sustainable approach, with no environmental risks. One of the key potential in carbon sequestration in our country ...
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All worldwide studies verifies global phenomenon of climate change caused by the greenhouse effect of carbon emissions on this planet. Carbon sequestration in terrestrial ecosystem is a sustainable approach, with no environmental risks. One of the key potential in carbon sequestration in our country is the watershed management biomechanical operations in the natural resources areas. This research was conducted to evaluate this operation options in north and middle parts of Zagros ecological zone in atmospheric carbon sequestration and to offer optimal options for these regions. For this purpose, in each of the provinces (Kermanshah, Lorestan, Kurdistan and Fars), one or more representative sites were selected. Then, soil, biomass and litter sampling were taken by field operations using systematic randomized method. Soil organic carbon and other soil physic-chemical properties and carbon stock of biomass and litter samples were determined in the laboratory. Then, carbon sequestration indices including soil, biomass, litter and total carbon sequestration, were measured per hectare. Analysis of the research results indicated that these operations are mainly planting of different trees along with flood and water spreading and bankets. Watershed management operations sequester up to 3.41 to 112.1 tons of carbon per hectare. Contribution of soil from total carbon sequestration was around 95 to 99 percent measured across different study site. Native terracing with tree planting of grapes (Vitis spp) and almond (Amygdalus spp) were the more efficient option in carbon sequestration along the selected areas.
Seyed Ali Ayyoubzadeh; Mahdi Habibi; Mohammad Rostami; Mojtaba Sanei; Mohammad Faramarz
Abstract
Side weirs are widely used to divert water from rivers. In movable bed rivers, deposition of sediment particles along the side weir may cause some problems in diverting water. This research is done in a laboratory flume of 0.9 meter wide and 10 meter long with a longitudinal slope of 0.001. Three value ...
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Side weirs are widely used to divert water from rivers. In movable bed rivers, deposition of sediment particles along the side weir may cause some problems in diverting water. This research is done in a laboratory flume of 0.9 meter wide and 10 meter long with a longitudinal slope of 0.001. Three value of weir length i.e. 0.6, 0.4 and 0.2 with a single weir height of 0.08 meter were used in the experiments. The variations of water surface profiles along the side weir were measured for various upstream Froude Numbers. The obtained results from experiments on movable bed condition were compared with those from rigid bed condition and also with the results from analytical solution. The results showed that bed form made by flow regime in the vicinity of the side weir does effect on the water surface profile over the weir and thus changes the diverted flow discharge. Water surface and discharges over the side weir were found in good agreement with the results obtained from the analytical solution in compare with the results obtained from channel with movable bed. The computed relative error for flow discharge in channels with movable and rigid bed is 6.35% and 24.18% respectively. This amount for variations of water surface profiles along the side weir is 8.03% and 9.88% respectively.
Tayeb Raziei
Abstract
Drought characteristics were investigated in arid and semi-arid regions of eastern and central Iran using monthly precipitation records of 69 synoptic and meteorological weather stations for the period 1975-2005. After quality control of the data records, the the ُStandardized Precipitation Index (SPI) ...
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Drought characteristics were investigated in arid and semi-arid regions of eastern and central Iran using monthly precipitation records of 69 synoptic and meteorological weather stations for the period 1975-2005. After quality control of the data records, the the ُStandardized Precipitation Index (SPI) was computed at 3, 6 and 12 month time scales for all considered stations. The target area was regionlized into a few distinctive homoginious sub-regions by applying principal component alalysis and Varimax rotation to the SPI time series computed for 3-, 6- and 12-months time scales, i.e., the target area is composed of two homeginous sub-regions based on SPI at 3- and 12-months time scales, while it classified into 3 sub-regions considerng 6-months time scale. Drought charcteristics (severity, duration and frequency) were also identified for all considered stations and time scales and their respective spatial variability were analysed. The results indicate that drought events with different types of severity are more frequent in northern part of the studied area, while south-eastern part of the region is prone to severe to extreme drought events. The results also suggest that the target area experienced wide spread droughts in 23.5% of the years alaysed. In such years, the ratio of stations hited by severe to exterme droughts are lesser than the number of stations affected by mild to moderate drought events, indicating that the more severe drought the lesser areal extent.
Reza Sokouti; Hamidreza Peyrowan; Davood Nikkami; Mohammadhossein Mahdian
Abstract
Considering to high distribution of the marly lands in west Azarbaijan province and high sediment yield of such lands, in this research, the relation among the form and the rate of erosion on marls with their erodibility properties were studied. So marly regions of province with the special properties ...
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Considering to high distribution of the marly lands in west Azarbaijan province and high sediment yield of such lands, in this research, the relation among the form and the rate of erosion on marls with their erodibility properties were studied. So marly regions of province with the special properties were recognized and soils were sampled. Soil erodibility indices were determined and analyzed by statistical methods considering the form and the rate of erosion. Also portable rain simulator were used to study of the runoff and sediment yield potential of such soils. Finally the factors affected the soil erodibility were determined by variance analysis. Results showed erosion rate could be classified as moderate. Gully erosion had highest number in Gara-agaj and Gara-tape areas whereas rill erosion had high number in all area of marlly lands. Surface runoff volume ranged between 255 to 577 cm3 in Shabanlu and surface runoff coefficient 0.23 to 0.53 in Gara-tapeh. Maximum yielded turbidity was 180 gr/lit in Gara-Agaj area. Clay ratio was the effective factor to gully form and Surface runoff volume also was the factor to form surface and rill erosion.
Rahim Kazemi; Samad Shadfar; Reza Bayat
Abstract
Information on the hierarchical importance of the factors influencing on the spatial distribution of springs in a watershed are required for the development of the water quality and quantity management plan. In this regard, we address the integration of GIS and decision support tools, for zoning prone ...
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Information on the hierarchical importance of the factors influencing on the spatial distribution of springs in a watershed are required for the development of the water quality and quantity management plan. In this regard, we address the integration of GIS and decision support tools, for zoning prone areas. In this research to determine hierarchical importance of the elements on the water resources development in Karst regions, first with literature review and field studies, the effective parameters in occurrence of spring were selected. Then thematic layers of these parameters in GIS environment were prepared. Each layer separately crossed with the spatial distribution of spring's layer and priorities of each sub layer with respect to each other in terms of frequency of spring's occurrence were determined. Finally, using the analytic hierarchy process, factors affecting the occurrence of this phenomenon and the weight of each factor was calculated by Expert Choice software. Results showed that the weight of the top layer assigned to the lithology and carbonate substrate alone formed 54% of the weight of this layer. The next layers in order of importance were including the layer of the slope and elevation classes, structural elements, lineaments, limestone contact and drainage layer. Potential map prepared by this method, match 76 percent with the spatial distribution of springs.
Somayeh Jafari; Reza Bayat; Amirhossein Charkhabi; Nader Jalali; Fazel Iranmasnesh
Abstract
Sand dunes developed in 15 provinces with an area of 4.4 million hectares and 56 Citadel, are one of the most important geomorphological features in Iran. Sand and desert stabilization technical office studies, according to project results identify focal and present four regions including Ahvaz, Dasht-e-Azadegan, ...
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Sand dunes developed in 15 provinces with an area of 4.4 million hectares and 56 Citadel, are one of the most important geomorphological features in Iran. Sand and desert stabilization technical office studies, according to project results identify focal and present four regions including Ahvaz, Dasht-e-Azadegan, Susa and the Omidiyeh in Khuzestan province. The mentioned area includes 279,505 hectares of land in Khuzestan. This study has used remote sensing technology, GIS techniques and analyzed effective recorded winds data. Toward were reviewed and analyzed the wind regime of the area for direction of source area using Windrose Diagrams. In this study, based on utilizing and composing of image processing techniques such as image enhancement, threshold, false color composition, filtering and analysis and results of wind data analysis, with other investigations is useful to find the source of sand dunes. The results from direction of source area confirm that source of sand dune located in NW to W, notice Windrose in Khuzestan. The source area are flood alluvial fan plain, alluvial fan, agriculture land, meandering rivers and sensitive formation to erosion including Aghajari formation and Bakhtiari formation that located in the in NW to W section.
Mansoor Mehdizadeh Youshanloe; Mohammad Roghani
Abstract
Establishing permanent plant cover with economical efficiency is one of the approaches to control water erosion of piedmonts. For this purpose making rain water harvesting micro catchments systems for collecting enough rainwater by increasing surface runoff coefficient of catchment is necessary especially ...
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Establishing permanent plant cover with economical efficiency is one of the approaches to control water erosion of piedmonts. For this purpose making rain water harvesting micro catchments systems for collecting enough rainwater by increasing surface runoff coefficient of catchment is necessary especially about low daily rainfalls. Created for rainwater catchment systems in arid and semi-arid areas is essential. The project is located in 30 km. Eastern south of Urmia city in West Azerbaijan. The dimension of runoff area is 5×6 square meters. Construction three treatments in four replications. The rainwater plots built with surface treatments of impediment, semi-impediment and natural surface with 4 blocks. That’s located on southern hillside with slope 12 to 15 percent. The Urmia synoptic station selected and prepared frequency of daily rainfall of every month with depths of more than 0, 1, 5 and 10 mm for period of 50 years. The results showed that average frequency of daily rainfalls with depth of equal or more than 1 and 5 mm for warm month (season of plants growth and production) include July, August and September was for every one year and one for every 3 years respectively. So the threshold of daily rainfall for runoff occurrence due to treatments of impediment, semi impediment and natural respectively are 2.5, 3.5 and 4.4 mm and percent of runoff coefficient 41.17, 10.58 and 1.74 for period of May to November of every year. Conclusion is that application of impediment rainwater catchment associated with runoff reserve system on rainy months (April and May) and reserved water distribution system on more water needy months (July, August, September) is recommended.
Manouchehr Amiri; Hamidreza Pyrowan; Ahmad Ahmadi Khalaj
Abstract
Since marls are highly sensitive to erosion and they annually sent thousands tons of fine grains sediments and clay to reservoirs of dam and artificial feeding stations and increase the cost of filtration of drinkable water and phytoremediation of artificial feeding water greatly, so the studies of different ...
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Since marls are highly sensitive to erosion and they annually sent thousands tons of fine grains sediments and clay to reservoirs of dam and artificial feeding stations and increase the cost of filtration of drinkable water and phytoremediation of artificial feeding water greatly, so the studies of different aspects of marls are important for experts and researchers. In this study we have tried to classifying them and recognizing effective variables of marls classification and examine the relationship between marls groups whit the types and erosional intensity of them. For this purpose, samples were taken from 41 points and they were sent to the laboratory to determine the values of the physical and chemical parameters. The characteristics of the location of the samples such as slope, geographical location and the privilege of seven parameters for soil surface factor and so on were noted. The test of artificial rain was done by kamphorst΄s rainfall simulator apparatus in the adjacent of mentioned points and samples were taken to measure the amount of runoff and sediment of them in the laboratory by simple methods. Furthermore, to identify the types of minerals presenting in the marls and diagnosis of their age, seven samples were analyzed by x-ray diffractometer and eight thin sections of marl and rocks collected along with them such as sandstone and limestones were provided and studied by polarizing microscope. Then, the abnormal data were normalized by logarithm and afterwards, all data were evaluated by cluster analysis, discriminant analysis and scalogram method. Results indicate that the marls are respectively divided into four (S1, S2, S3, S4), five (P1, P2, P3, P4, P5) and six (T1, T2, T3, T4, T5, T6) groups based on their chemical, physical variable and their combination. Fisher linear functions obtained from the classification predict the marl groups, respectively, with an accuracy of about 96.5, 83.9 and 96.9 percent in a correct way that the chemical variables are more appropriate for classification. This study shows that the marls containing a small amount of neutralizating material with high liquid limit are capable of higher erodibility.
Mohsen Zabihi; Seyed Hamidreza Sadeghi; Mehdi Vafakhah
Abstract
Soil erosion as a threatening phenomenon for the world population is mostly the result of the combined effects of unsuitable land use and climatic factors. Among climatic factors, rainfall is considered as one of the main causes of soil erosion and therefore detailed study of the different properties ...
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Soil erosion as a threatening phenomenon for the world population is mostly the result of the combined effects of unsuitable land use and climatic factors. Among climatic factors, rainfall is considered as one of the main causes of soil erosion and therefore detailed study of the different properties of rainfall such as rainfall erosivity is necessary. However, investigation of spatial variability of rainfall erosivity factor at different scales at national level has been less considered. Therefore, the present study aimed to investigate the spatial variability of rainfall erosivity factor in Universal Soil Loss Equation (USLE) for monthly, seasonal and annual scales in Iran. Towards this attempt, the amounts of rainfall erosivity factor were calculated through calculation of kinetic energy and maximum 30-minute intensity over 12,000 showers occurred at 70 stations in the study period of 20 years (1984-2004) in Iran. The spatial patterns of temporal variation were also in different time scales. According to the results, existing stations in the south west and north of the country had the first priority of annual rainfall erosivity factor hazard. The west and south west stations and south east stations had also the highest and the lowest seasonal and monthly risk rainfall erosivity factor, respectively. Also, results showed Tangpich in Khuzistan, Anzali in Giulan and Poleshalo in Khuzistan had the maximum rainfall erosivity factor whereas Bande Enherafi in Semnan, Tabas in South Khorasan and Bam in Kerman Provinces had the minimum annual rainfall erosivity factor hazard country wide. The average annual rainfall erosivity factor in the country was ultimately obtained 14.13 tm.ha-1.cm.h-1.
Jahangir Porhemmat; Hadi Nazaripooya
Abstract
Infiltration is one the most important components of hydrologic cycle for utilization and managements of water resources. This phenomenon is affected by several factors and its measurement is difficult. Therefore, several models have been introduced for the simulation of infiltration. Previous studies ...
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Infiltration is one the most important components of hydrologic cycle for utilization and managements of water resources. This phenomenon is affected by several factors and its measurement is difficult. Therefore, several models have been introduced for the simulation of infiltration. Previous studies in evaluation of infiltration models show that each model can be preferred over others in a specific condition. Considering this fact, six infiltration models including Philip, Horton, Green-Ampt, SCS, Kostiakov and Luise-Kostiakov and thier parameters were evaluated. Gonbad catchment in Hamedan province was selected and it was divided into four homogenous hydrologic units. Then infiltration was measured during the dry season by double ring. The results showed that Philip model was the most accurate for estimating of the infiltration and Kostiakov model is also the second one. Regression coefficients of Philip model were betwean 0.975 to one, mean error -0.017 to +0.017 and the maximum root mean square error was 0.22. Regression coefficients of Kostiakov model were between 0.956 to 0.998, mean error -9.3 to +0.003 and the maximum root mean square error was 14.25. In addition, the correlation relations between parameters of these models and two soil texture indices were carried out. The findings show that except for SCS model, the other parameters correlate with these two indices in a 5% level and at least one parameter of each model has high correlation with them. Regression coefficient for A in Philip model, B in Green-Ampt, k in Horton, b in Kostiakov and b in Luise-Kostiakov were 0.99, 0.95, 0.99, 0.999 and 0.96 respectively. Results show a lower correlation between the other parameters and the percentage of clay and sand. Based on these results, it is suggested that the regression relations of models’ parameters for different conditions of soil texture and antecedent moisture in a variety of basins should be evaluated and determined.
Ahmad Ahmadi; Farhang Ghasriani; Anvar Sanaei; Mina Bayat
Abstract
The purpose of this study was to determine the Evaluation of different cutting intensity on some attributes of Teucrium polium and Helichrysum globiferum Gharebagh key species. In this first region and two key area of half hectare in area Gharebagh and in the first year and was grazed, and fencing. Selected ...
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The purpose of this study was to determine the Evaluation of different cutting intensity on some attributes of Teucrium polium and Helichrysum globiferum Gharebagh key species. In this first region and two key area of half hectare in area Gharebagh and in the first year and was grazed, and fencing. Selected and removed from any of 0, 25, 50, 75% and control is exercised (a basic 10 treatments). Monthly by the clipper and the area is grazing season. Effective utilization of changes in the phenological characteristics, forage and seed production, vitality, mortality and other characteristics of selected plants species were studied. Finally, the combined analysis of data from yield and vigority with a split plot design in SAS software was analyzed. Results of studies of the effects on forage production and harvest of T. polium and H. globiferum Gharebagh species studied showed that effects of different levels, different years, and their interactions on the production level is a significant percentage (p<0.01). This shows that in different years with different weather conditions of production are different. The research findings can be taken as authorized by the 50% cutting intensity for the T. polium and 25% for H. globiferum are suitable.
Kamal Nabiollahi; Ahmad Haidari
Abstract
Arsenic has been recognized as a toxin element for human. Minerals frequency can affect on arsenic content and Sufficient mineralogical characterization of contaminated sites should assist geochemical models that assess the potential of natural attenuation remediation of a subsurface contaminated with ...
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Arsenic has been recognized as a toxin element for human. Minerals frequency can affect on arsenic content and Sufficient mineralogical characterization of contaminated sites should assist geochemical models that assess the potential of natural attenuation remediation of a subsurface contaminated with arsenic. In order to mineralogy investigation in the arsenic soil in Bijar area, 83 profiles were selected based on the prepared geopedology map and 229 soil and 15 parent material samples were collected. Routine physical and chemical characteristics and soil arsenic contents were measured in all samples. Relative quantity and types of clay and powder minerals were determined for 35 soil and 15 parent material samples by XRD analysis. Smectite, illite, kaolinite, chlorite and vermiculite were the most important clay minerals in the region. enargite, arsenoilte, sphalerite, nicoolite, conichalcite, arsenosulvanite and cobaltite based on the powdery mineralogy results were the most important arsenic bearing minerals in the region. The type and content of minerals were different and their content were higher in the profiles with very high arsenic. In the mudston and Fe-rich rock arsenic concentration are higher compared to the other parent materials. Also the minerals content were higher in the mudston and Fe-rich rock compared to the other parent materials.
Anvar Sanaei; Mohammadali Zare Chahouki; Esmaeil Alizadeh; Omid Asadi Nalivan
Abstract
The aim of this study was to evaluate the effects of grazing intensity around water resources on vegetation characteristics. For arrive this goal, three water points selected in the Silve watershed of Piranshahr rangelands. Around of each water point two regions with 0-150 and 150-300 meter intervals ...
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The aim of this study was to evaluate the effects of grazing intensity around water resources on vegetation characteristics. For arrive this goal, three water points selected in the Silve watershed of Piranshahr rangelands. Around of each water point two regions with 0-150 and 150-300 meter intervals separated. In the four geographical direction and in each distance, a 150 m transect established (total 12 transects), and along of each transect with 15 m intervals a 1 m 2 plot was placed (total 240 plots). Sampling was done with random-systematically method, the list of exist species, canopy coverage, percent of species composition class I, II, III and number of individuals per species were recorded for each plot. Analysis of the data in factorial on the base of complete randomized block design and to calculate diversity, richness and evenness with past software was done. The results showed that there is significant difference (p<0.01) in percentage composition of class I, II, III, annual, perennial plants and total canopy cover. The highest composition percentage and density of the species Br. tomentelus (1.48 and 4.35 respectively) and Fe. ovina (1.12 and 3.44 respectively) was observed. Between water points except annual species composition percentage in the other studied properties there are significant difference (p<0.01). Maximum amount of Shannon wiener and Margalef index there are in second distance of third water point and were 2.18 and 4.10 respectively. The Pielou evenness index was non-uniformly in both distance and three water points.
Maryam Azinmehr; Abdolreza Bahremand; Atena Kabir
Abstract
The various types of land cover and land use have significant roles and impacts on runoff and flood; but how and to what extent is not clear and highly uncertain. The models are becoming more capable for flood prediction, landuse impacts on floods, and decision making in watershed management. The main ...
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The various types of land cover and land use have significant roles and impacts on runoff and flood; but how and to what extent is not clear and highly uncertain. The models are becoming more capable for flood prediction, landuse impacts on floods, and decision making in watershed management. The main objective of this research is to assess the impacts of land use changes on flow hydrograph by means of distributed modeling and GIS. A grid-based spatially distributed hydrologic model, WetSpa, which has been developed at the Department of Hydrology and Hydraulic Engineering of VUB, is used in this research to fulfill the aim. The basic model inputs are a digital elevation model (DEM), land use and soil maps of the study area in GIS raster format, and hydrometeorological data. The model is applied to the Dinvar river basin (1717 km2), and its main tributaries. The Dinvar river located in Kermanshah, is one of the main tributaries of the Karkheh River. The model predicts the daily hydrographs with a good accuracy, 66% according to the Nash-Sutcliffe. For assessing the impact of landuse changes on floods, the calibrated model is applied for nine scenarios using the hourly data. The potential of Dinvar cachment, nine landuse change scenarios in GIS was determined and entered the calibrated model for simulation. changes in processes and hydrological parameters were investigated by comparing the output hydrograph of present landuse with simulation result of 9 scenarios. Results show that model simulation is acceptable as for the result of model.
Aboalhasan Fathabadi; Hamed Rouhani; Seyed Morteza Seyedian; Mohammad Mahdvi
Abstract
When watershed input, evatransporation and ground water usage be limitated, recession curve showed storage–output relationship for basin. This relationship can help us in low flow forecasting, decision and management of water resources; hydrological models calibration and etc. In this study recession ...
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When watershed input, evatransporation and ground water usage be limitated, recession curve showed storage–output relationship for basin. This relationship can help us in low flow forecasting, decision and management of water resources; hydrological models calibration and etc. In this study recession curve were modelled in Taleghan, Jajrod and Khoramdare rivers. At the first by consideration of annul hydrographs, recession lamb were separated then by doing some pre-processing recession curve get prepared for fitting various models. For each recession eight models were fitted. Result showed that for Jajrod and Talaghan, Barnes, Drogue, Coutagne and Wittenberg had better application, respectively. For Khoramdare river Horton, Barnes and Drogue had better performance with compared to others models. For Barnes model average value of K coefficient for Jajrod 0.97, 0.975 and 0.99, for Taleghan 0.967, 0.974 and 0.987 and for Khoramdare river 0.931, 0.945, 0.972 were obtained.
Leila Esmaeelnejad; Hassan Ramezanpour; Javad Seyedmohammadi
Abstract
Marls are the most talented geological formation of erosion and produce large amount of sediments that annihilate fertile soil and deduct the capacity of dams. Erosion in marls depends on external factors such as distribution of rainfall and internal factors which include soil physical and mineralogical ...
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Marls are the most talented geological formation of erosion and produce large amount of sediments that annihilate fertile soil and deduct the capacity of dams. Erosion in marls depends on external factors such as distribution of rainfall and internal factors which include soil physical and mineralogical properties. Therefore, the objective of this research was to determine erosion variations because of the changes of physical and mineralogical properties of marls in arid regions of Guilan Province (Gilevan region) located in Northern Iran. The concerned soil physical properties of marly lands were percentage of saturation, surface gravels, sands, silts, clays, fine sands, fine clays, and the level of bulk density, mean weight diameter (MWD) of soil aggregates (dry sieve), liquid limit, plastic limit, activity and ratio of fine clay to total clay. In addition, four samples from Marly soils were prepared for X-ray diffraction analysis. Comparing the average of physical factors with different type of erosion by means of Duncan multiple range test showed that the percentage of clays, fine clays, saturation, and the level of MWD, liquid limit and activity showed significant changes (p<0.05) in some types of erosion, whereas other measured parameters had no significant effect on the form and type of erosion. Furthermore, results of X-ray diffraction showed the presence of smectitic group clay minerals that are dispersive (2:1 clays), in badland and gully areas, while these types of clay minerals were not found in areas with rill and sheet erosion. Hence, with respect to the results of this research, it can be concluded that mineralogical properties such as smectitic clays, as well as some soil physical characteristics such as clay percentage, fine clay and mean weight diameter are the main factors controlling the shape and form of erosion in marly lands of Northern Iran.
Akram Lalozaei; Mohammadreza Dahmardeh Ghaleno; Mahdiye Ebrahimi
Abstract
The aim of this research is to study the impact the establishment of two types of windbreak, namely Tamarix aphylla and eucalyptus, on the soil characteristics in the Hamon plain, Sistan, Iran. In order, for each of the two species, a transect was set in 1.5 meter from plant canopy of the tree as treatment ...
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The aim of this research is to study the impact the establishment of two types of windbreak, namely Tamarix aphylla and eucalyptus, on the soil characteristics in the Hamon plain, Sistan, Iran. In order, for each of the two species, a transect was set in 1.5 meter from plant canopy of the tree as treatment and a transect in distance of 50 meters from the trees as control. 30 points on each transect was selected and soil samples were taken at three depths (0-10, 10-30, 30-60 cm).The data of electro conductivity, acidity, the ratio of carbon to nitrogen, organic matter, potassium, magnesium, calcium, sodium, and texture of the soil, were analyzed using the SPSS software, paired t-test and analysis of variance in a randomized block design. Results showed that with the construction of the two windbreaks, electro conductivity, organic matter, calcium, potassium, sodium and carbon to nitrogen ratio had a significant (95%) increase compared to the control region. Furthermore, results showed that Tamarix aphylla in compared to eucalyptus, caused more increase in sodium, electro conductivity, and soil salinity, despite the fact that it causes an increase in organic C/N, carbon to nitrogen ratio, calcium, and potassium. In general, compared to eucalyptus, Tamarix aphylla windbreak has a better compatibility with the climate in the region Positive impact on soil properties, increasing soil organic matter levels and in the Long-term will help improve soil structure and soil also increases the necessary materials (nitrogen, phosphorus and potassium), the has more positive effects on the characteristics of the soil.
Nadegholi Ebrahimi; Aliakbar Davudirad
Abstract
In order to investigate of geological formation effects on sediment yield in Gharah Kahriz watershed at first by overlaying the base maps such as land type, geology, slope and vegetation, the unit land map were obtained. The amount of sediment yield calculated using MUSLE model in each homogen unit. ...
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In order to investigate of geological formation effects on sediment yield in Gharah Kahriz watershed at first by overlaying the base maps such as land type, geology, slope and vegetation, the unit land map were obtained. The amount of sediment yield calculated using MUSLE model in each homogen unit. In order to achieve the objectives of the study, units that was widespread in the region and were almost homogenous in land use, slope and vegetation and the only difference was the type of geological formation, were selected. The results show that the maximum amount of sediment yield during flood events were observed in Kmml unit that contains layers of limestone and marl with average of 13.34 t.ha-1, and the minimum amount of sediment yield belongs to the Js unit that compound of Jurassic sandstone with average of 0.20 t.ha-1.
Mahdi Erfanian; Mansor Bayazi; Hirad Abghari; Abazar Esmali Ouri
Abstract
Soil erosion from socio-economic and environmental aspects of view is important, and decision making for applying proper watershed management practices is essential to control or mitigate it. In recent years, the Soil and Water Assessment Tool (SWAT) model as widely-used tool have been applied to simulate ...
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Soil erosion from socio-economic and environmental aspects of view is important, and decision making for applying proper watershed management practices is essential to control or mitigate it. In recent years, the Soil and Water Assessment Tool (SWAT) model as widely-used tool have been applied to simulate flow discharge, sediment yield, and to evaluate watershed management practices in reducing runoff and sediment yield. This research aims to simulate monthly flow discharge and sediment yield using the SWAT model to identify critical sub-watersheds yielding specific sediment in Nazlochai watershed, located in the West of the Urmia Lake. In this study, a monthly stream flow and sediment discharges data series were used during 1997–2007 for model calibration and 1993–96 for validation. To evaluate model efficiency, some statistical criteria consist of the determination coefficient (R2), the Root Mean Square Error (RMSE), the Nash-Sutcliffe Efficiency (NSE), and the Mean Bias Error (MBE) was used. For the sake of model calibration, validation and uncertainty analysis, the SUFI2 program was utilized, which it is included in the SWAT-CUP software as a public domain program. The NSE values for simulating monthly flow discharge in calibration and validation periods were 0.7 and 0.85, while for monthly sediment discharge simulation were 0.65 and 0.75, respectively. The evaluation criteria showed that the model is satisfactory capable to predict monthly flow and sediment discharges. To identify critical areas, the calibrated model was applied in validation period. Out of 17 sub-watersheds, sub-watersheds 17, 13, and 16 with the highest amounts of Specific Sediment Yield (SPY) in ton/ha/year were identified as critical sub-watersheds and were prioritized respectively for soil conservation and management purposes.
Saeed Rashvand; Negin Shirzad; Hassan Yeganeh
Abstract
The goal of rangeland management is preservation, restoration, development and sustainable utilization of rangeland resources. In this study, species Bromus tomentellus is one important, species of site is the mountains of Qazvin’s Alamut has been studied. In order to do the research, first area ...
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The goal of rangeland management is preservation, restoration, development and sustainable utilization of rangeland resources. In this study, species Bromus tomentellus is one important, species of site is the mountains of Qazvin’s Alamut has been studied. In order to do the research, first area equivalent to 0.5 acres was selected and through operations grazed has been enclosed in the first year of study. In above species, 40 stocks has been selected, that monthly in the season has been cut in up to; 25, 50, 75, by hush’s scissors. Also, for every 10 base has been applied to a control treatment. the end he effect of changes in the operating characteristics of phonological, Forage production, vitality, mortality and other characteristics has been studied of selected species. The results showed that increase of 75% in utilization and deterioration caused negative effects on the critical capabilities and Harvest limit of 50% with the lowest incidence of adverse effects on plant characteristics and capabilities were proper.
