M Abbasi; M Mohseni Saravi; M.M Kheirkhah; Sh Khalighi Sigaroudi; Gh Rostamizad; M Hosseini
Volume 63, Issue 3 , December 2010, , Pages 375-385
Abstract
Assessment of watershed management activities is one of the main subjects for future planning of practical projects and natural resources management. Due to the lack of any tool for assessment of watershed processes in many cases, distributed hydrological models can be useful. The purpose of this study ...
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Assessment of watershed management activities is one of the main subjects for future planning of practical projects and natural resources management. Due to the lack of any tool for assessment of watershed processes in many cases, distributed hydrological models can be useful. The purpose of this study was evaluation of watershed management activities in Kan Watershed by HEC-HMS (Hydrologic Modeling System). For this purpose, first by considering observed events, HEC-HMS model was optimized and calibrated. Then, for evaluating the effects of check dams on time of concentration, it was calculated before and after of check dam's construction by use of field observations and vegetation cover improvement was also estimated after the project. These parameters were imported to HEC-HMS to find out the effects of watershed practices and then flooding condition was simulated. For assessment purposes, peak discharge and flood volume were calculated for “before” and “after” construction conditions. Results showed that check dams as mechanical measures had low effect on time of concentration while biological practices lead to decrease in curve number with an average value of 3.1. This effects result in decrease of peak flow and flood volume meanly 21% and 11%, respectively.
mahshid souri; mina gayeb; Javad Motamedi
Abstract
Rangelands, using a variety of renewable natural resources are as well as economic value, in terms of effects on soil and water conservation that are very important. This study was conducted in Nushan West Azerbaijan province. Determining the susceptible areas of rangeland to degradation done by out ...
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Rangelands, using a variety of renewable natural resources are as well as economic value, in terms of effects on soil and water conservation that are very important. This study was conducted in Nushan West Azerbaijan province. Determining the susceptible areas of rangeland to degradation done by out ranking technique PROMETHEE II was used. In this study, to determine the rangeland susceptible to degradation used numerous effective criteria such as precipitation, slope, erosion, sediment, runoff, discharge, production, pasture conditions, pH, conductivity, organic carbon, soil, land use, population density and the presence of villages in the catchment area of 7439 hectares was used. Weight criteria were determined using the Shannon entropy. Due to the weight and value of criteria for each vegetation type, analyzed data for each of them using PROMETHEE II. Finally, the rangeland degradation areas were divided in 3 category including; high, moderate and low classes by using K-means method.
Seyed Masoud Soleimanpour; Bahram Hedayati; Majid Soufi; Mohammad Javad Rousta; Samad Shadfar
Abstract
One of the important relations in the erosion of gullies is to study the threshold of erosion creation and expansion. In recent decade, creation of new knowledge in determination of relation between variables was led to develop prediction methods in different science and therefore, investigating the ...
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One of the important relations in the erosion of gullies is to study the threshold of erosion creation and expansion. In recent decade, creation of new knowledge in determination of relation between variables was led to develop prediction methods in different science and therefore, investigating the ability to use these methods in erosion and soil conservation is essential. Also, in order to control the erosion of the gully, the mechanism of gullies growth and its dimension expansion, especially increasing in gullies length, has to be carefully determine; for this purpose, the present study aimed to determine the threshold of the most effective factors on increasing the length of the gully, using the K-Means data mining algorithms and the CART decision tree in the Ghazian watershed in the north of Fars province. The results of this study, which include measuring various variables of gullies under field condition and in laboratory, and using data mining techniques, showed that increasing the length of gully in this area depended on the factors of the area above headcut, saturated extract electrical conductivity, forehead slope, canopy cover percentage, and sodium adsorption ratio. It is recommended control of erosion in the foreheads is highly important in reducing the increase in gullies length and sediment production. Also, improving the soils of this area with soil amendments and the restoration of compatible vegetation and the increase in soil organic matter should be considered as the priority of effective actions to control the increasing length of gullies.
Raziyeh Safiyari; Fereydoon Sarmadian; Ahmad Heidari; Shirin Younesi
Abstract
Evaluation soil erosion is an important matter to protecting it from destroying in future due to the excessive use of the inherent capacity of soil and also improper management. Therefore, in this study land vulnerability related to water and wind erosion of Abyek for crops and pasture land has been ...
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Evaluation soil erosion is an important matter to protecting it from destroying in future due to the excessive use of the inherent capacity of soil and also improper management. Therefore, in this study land vulnerability related to water and wind erosion of Abyek for crops and pasture land has been evaluated, using Raizal model as one of the Microleis sub-models. Morphological and physical and chemical analysis data were obtained of studying and evaluating the 32 soil profiles. Agricultural - climatic and management information including temperature and precipitation data were collected from Bagh-e-Kosar climatological station for the last 17 years. To study the effect of climatic changes in the assessment of land area for the year 2080 AD (for 70 future year), the reports of International Panel on Climate Change (IPCC) allocated to West Asia have been used. Utilization types considered for evaluation, including wheat, corn, barley and alfalfa. The results obtained of Land vulnerability evaluation studies related to water and wind erosion using Raizal model part have been prepared as maps in the GIS environment. Information obtained from Land vulnerability models related to wind erosion for crops and pasture land, also implies vulnerability risk fora wide percent of the region lands under the current management, that the results evaluation of the proposed management methods express the improvement of destroying ability classes.
Mysam shafie; Mohammad Ali Alizadeh; Ali Ashraf Jafari
Abstract
In order to study, the effect of pre-cooling treatment, osmotic potential and water stress on some population of two species of Satureja bachtiarica and Satureja sahendica was studied by a factorial experiment based on completely randomized design with three replications in laboratory and greenhouse ...
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In order to study, the effect of pre-cooling treatment, osmotic potential and water stress on some population of two species of Satureja bachtiarica and Satureja sahendica was studied by a factorial experiment based on completely randomized design with three replications in laboratory and greenhouse conditions during one year in the gene bank of Institute of forests and range lands by the years of 2010-2011. In laboratory, treatment were including: cold and osmotic potential making of polyethylenglycol (PEG) 6000 Da in 5 concentrations (0, -0.3, -0.6, -0.9, -1.2 Mgapascal) compared with control. In greenhouse, treatment were including: cold and drought stress in five levels of field capacity (100,80,60,40,20) compared with control. Result showed that seed germination and seed emergence were decreased as rate of 33% and 6% in order of laboratory and greenhouse condition with increasing of osmotic potential and water stress while the ratio of root to shoot and ratio of dry weight to fresh weight was increased. In both experimental conditions, the most of the seed characteristics were higher with pre-cooling than other treatments. In response to osmotic potential in germinator, and dry stress in greenhouse, Bijar 2 population from Sahandy savory and piranshar from bachtiary savory showed more tolerant to dry stress due to have more vigor index and ratio of dry weight to fresh weight and they introduced as superior population.Comparing of the population showed that population of the takestan of Sahandy savory had lower tolerance.
E. S. Shokoohi; Gh. R. Zehtabian; A. Tavili
Abstract
More than 80% of Iran’s area has arid and semi arid climate. Therefore, Iran is exposed to desertification process. Practical activities in controlling desertification must be based on current desertification situation and its severity. Based on this theory, evaluating desertification rate indices ...
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More than 80% of Iran’s area has arid and semi arid climate. Therefore, Iran is exposed to desertification process. Practical activities in controlling desertification must be based on current desertification situation and its severity. Based on this theory, evaluating desertification rate indices in Khezrabad region was done based on IMDPA model. In this research two factors with 10 indices were investigated. Each of the investigated indices was analyzed and scored based on work units. Data layers of each index were made by Arc GIS software. By compiling data layers and calculating geometric mean of indices, desertification rate map of the region was then prepared. According to the selected indices, final desertification map shows the mean rate of desertification. Soil index by 2.21 scoring value was classified in median class while water index by 1.46 scoring value was classified in poor class. Soil depth had the biggest influence while SAR and Cl of water had the least influence on desertification. Based on the assessments, geometrical mean of desertification rate quantity value for the entire region was 1.76, thus the entire region was classified in median class.
Sadegh Sadeghi Tabas; mohsen Pourreza bilondi
Abstract
Rainfall-runoff modeling is most important component in the water resource management of river basins. The successful application of a conceptual rainfall-runoff model depends on how well it is calibrated. The degree of difficulty in solving the global optimization method is generally dependent on the ...
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Rainfall-runoff modeling is most important component in the water resource management of river basins. The successful application of a conceptual rainfall-runoff model depends on how well it is calibrated. The degree of difficulty in solving the global optimization method is generally dependent on the dimensionality of the model and certain of the characteristics of object function. The purpose of optimization is to finalize the best set of parameters associated with a given calibration data set that optimize the evaluation criteria. In the present study an uncertainty analysis of conceptual rainfall - runoff model (Hymod) were evaluated and compared using the four different evolutionary optimization methods for a Leaf River representative watershed in US. Results appealed that particle swarm optimization (PSO) and shuffled complex evolution (SCE) algorithms had better performances compared to Hybrid Genetic Algorithm & PSO (Hybrid-GA&PSO) and Shuffled Frog Leaping Algorithm (SFLA).
Paria Kamali; Reza Erfanzadeh; Hasan Ghelichnia
Abstract
This study aimed to investigate the effect of animal grazing on soil seed bank characteristics in the northern slopes of Alborz. For this purpose, soil seed bank characteristics were compared between grazed and ungrazed areas. Therefore, four transects perpendicular to the sides of exclosure inside and ...
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This study aimed to investigate the effect of animal grazing on soil seed bank characteristics in the northern slopes of Alborz. For this purpose, soil seed bank characteristics were compared between grazed and ungrazed areas. Therefore, four transects perpendicular to the sides of exclosure inside and outside of it were established. Then soil samples were collected within 28 plots inside and 28 plots outside of exclosure along the transects from two different depth: 0-5 and 5-10 cm. Soil samples were then spread in the greenhouse and the plant species germinated in the greenhouse were identified and removed one time per 12 days. General linear model and factorial was used to study on the effect of grazing, depth and interaction between grazing and depth on soil seed bank characteristics. In case that the interactions became significant, unpaired t-test was used to compared seed bank characteristics between grazed and ungrazed in each depth, separately. In addition, paired t-test was applied to compare seed bank characteristics between two depths in grazed and ungrazed areas, separately. The results showed that all seed bank characteristics were significantly higher in ungrazed than grazed area particularly in upper layer of soil. All seed bank characteristics were also significantly higher in upper layer than the deeper layer of soil. The results implied that soil seed bank is a reliable source to recover the over grazed degraded points in the study area.
Ali Golkarian
Abstract
Erosion is one of the important factors in soil degradation and decrease fertility and slope length is one of the most effective factors in land form and amount of erosion. The objective of this study was investigation of spatially variation of sediment concentration in slope length until to receive ...
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Erosion is one of the important factors in soil degradation and decrease fertility and slope length is one of the most effective factors in land form and amount of erosion. The objective of this study was investigation of spatially variation of sediment concentration in slope length until to receive transport capacity. To obtain this goal a hill slope simulator system designed and manufactured. This system include 10 flumes, each has five meter length which after series them become fifty meters. This system can produce cumulative flow via fifty watering can tube which are install on flumes with one meter interval and each flume discharging is 100 cc. Other variables include two type of soil and slope in three level 15, 22.5, 30 percent. Three replications were used for each treatment and totally 18 experiment was done. In each experiment four samples were gathered from end of each flume and concentration was determined. Complete randomized design with factorial arrangement was used for data analyzing. Richard’s function was used for fitting a suitable curve on observed data. Result was shown that effect of soil type on sediment concentration was not significant while slope and slope length effects was significant. Otherwise sediment concentration in the two last flumes was located in same class which is shown that sediment concentration achieved to transport capacity in this slope length. Also results were shown that Richard’s function can simulate trend of concentration variety in slope length.
zahra abdolalizadeh; Ataollah Ebrahimi
Abstract
Sabzkouh protected area, with the variety of natural ecosystems and landscapes, is very rich from the point of diversity in climate, topography, habitats and wildlife that is located in central Zagros. Evidences show that its ecosystems such as other Iranian semiarid natural ecosystems, undergone ...
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Sabzkouh protected area, with the variety of natural ecosystems and landscapes, is very rich from the point of diversity in climate, topography, habitats and wildlife that is located in central Zagros. Evidences show that its ecosystems such as other Iranian semiarid natural ecosystems, undergone changes in their vegetation structure over the past years. Obtaining multi-spectral and multi-temporal data via Satellite Remote Sensing (RS) with Geographical Information System (GIS) would be able to identify type, quantity and location of land use/land cover changes. The aim of present study is to detect land cover changes in recent three decades by RS in Sabzkouh region. Therefore, the images of Landsat MSS (1975) and Landsat ETM+ (2003), Digital Elevation Model (DEM) and Transformed Soil Adjusted Vegetation Index (TSAVI1) were used as ancillary data to obtain land cover maps. These maps were produced by applying supervised maximum likelihood classifier and included five classes namely: agriculture, herbaceous rangeland, shrub and brush rangeland, barren land and forest. To detect changes, Post Classification Comparison approach was used. The net change calculations indicated that were added to shrub and brush rangelands and forest. On the other hand, herbaceous rangeland and barren land have been converted to the other classes.
hamid hosseyni marandi; mohammad mahdavi; hasan ahmadi; baharak motamed vaziri; abdolali adelpour
Abstract
Abstract Common causes for groundwater quantity and quality changes are infiltration through the seasonal floodwater, effects of the artificial recharge projects and adjacent aquifers, and groundwater extraction for deferent uses. However, recognizing the impact of their contributions to these changes ...
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Abstract Common causes for groundwater quantity and quality changes are infiltration through the seasonal floodwater, effects of the artificial recharge projects and adjacent aquifers, and groundwater extraction for deferent uses. However, recognizing the impact of their contributions to these changes can be often challenging. Still, to understand the changes, monitoring groundwater level and several chemical factors are taken into consideration. Certain problems of course can complicate the analysis of the observations; for instance, insufficient data and manually prepared and measurement intervals can degrade the accuracy of such observations. In this paper, device-measured daily time series of Electrical Conductivity (EC), Temperature (T) and Groundwater Head (GH) are analyzed. The main purpose is to evaluate the groundwater changes and its relation to the processes on the aquifer surface in an arid region. Two wells (PZ2 and W20) with 1,200m distance from each other selected and installed a sensitive device for recording the groundwater level, temperature and salinity fluctuations. Time series of changes from December 2012 to July 2013, were analyzed. Groundwater head in PZ2 showed a decline but in W20 showed a minor rise. Salinity variations were different and were 15.3mS/cm in PZ2 and 1.7mS/cm in W20. The backdrop of increased salinity in the surface layers of groundwater in PZ2 identified and showing a correlation between groundwater head and salinity fluctuation with 83.5% R squire.
Forood Sharifi; samaneh arvandi; Ali Shahnazari
Abstract
Steam condensation system in soil is a new and developing method that is capable of regenerating land using renewable energy. In this method, the supply of water and moisture, is obtained from the air steam transferred directly to the root zone. The method is used to increase the moisture content of ...
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Steam condensation system in soil is a new and developing method that is capable of regenerating land using renewable energy. In this method, the supply of water and moisture, is obtained from the air steam transferred directly to the root zone. The method is used to increase the moisture content of different soils improved with organic matter. The results of this study showed that steam condensation has a significant role in increasing soil moisture and has a promising prospect. The moisture content stored in organic soils improved by more than 11% during the experiment. Statistical evaluation of measured data showed that with a 99 percent chance, the method can help to increase soil moisture. Also, with a 99% chance of changing these factors, it's best to increase soil moisture. By changing soil texture with a 95% probability, the best effect can be achieved in increasing moisture content. The results showed that soil with moderate texture, 35% organic matter and steam 45 ° C with coated conducting tube had better conditions than moisture and temperature in comparison with other treatments
somayeh dehdari; mehdi riasati; farhad fahkri; Morteza pozesh shirazi
Abstract
Understanding potential and capabilities in desert areas and Identification and introduction of plants compatible with those conditions, it is very important to modify hard and brittle conditions and forage production. In this study, to identify and introduce suitable pasture species for planting and ...
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Understanding potential and capabilities in desert areas and Identification and introduction of plants compatible with those conditions, it is very important to modify hard and brittle conditions and forage production. In this study, to identify and introduce suitable pasture species for planting and establishment with the aim of restoring vegetation in Bushehr Province, the species of Cenchrus cilliaris, Cymbopogon oliveri, Panicum turgidum and Sporobolus arabicus were used. For this purpose, during the spring of 1394, the seeds of the studied species were collected and cultivated in the second half of 1395. The traits included altitude, percentage of viability, canopy percentage and forage production in year and plant deployment rate. Data collected in a randomized complete block design were analyzed by SAS software and the means of the collected samples were compared with Duncan multi-domain test. Results showed that there was a significant difference between the species in the measured factors. The species P. turgidum, C. oliveri and C. cilliaris were respectively identified as the best species in the climate conditions of the Dashti district in Kaki. S. arabicus specie in some traits, it could have a significant statistical significance but was not meaningful in terms of deployment and compatibility.
Sharbanoo Abbasi Jondani; Ali Fathzadeh
Abstract
Snow is one of the main components of hydrological cycle in most of mountainous basins. Since collecting the snow data (e.g. snow water equivalent data) is very difficult and time consuming, some effort is necessary to develop methods to estimate spatially variation of snow depth distribution. In the ...
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Snow is one of the main components of hydrological cycle in most of mountainous basins. Since collecting the snow data (e.g. snow water equivalent data) is very difficult and time consuming, some effort is necessary to develop methods to estimate spatially variation of snow depth distribution. In the present study, the at-site SWE data of 14 stations located in the west of Isfahan providence for the period 1989-2010 were spatialized applying four methods composing the Kriging, the Co-Kriging, the Radial Basis Functions (RBF) and the Inverse Distance Weighting (IDW). In order to reach this purpose, first, the normality of data was checked using the Kolmogorov – Smirnov test. The homogeneity, the stability and the trend of data were tested employing the semivariogram approach. Then the appropriate data of each year was entered into the ArcGIS 9.3 to conduct the methods. Finally, the best method for spatializing the SWE data was selected based on the RMSE values. The results showed that the RBF method provided the best results for most of the years. Furthermore, it was found that the amount of SWE reduced from the south and west to the north and east of the basin.
zohre sepehri; Zeinab Jafarian; Ataolah Kavian; ghodratollah heydari
Abstract
Since fire effects on soil properties, awareness about effects of fire on soil is important for fire management. This study was carried out to investigate effects of fire on hydrological, physical and chemical properties of soil in Charat rangeland of Savadkuh. Sampling was performed in two plant types ...
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Since fire effects on soil properties, awareness about effects of fire on soil is important for fire management. This study was carried out to investigate effects of fire on hydrological, physical and chemical properties of soil in Charat rangeland of Savadkuh. Sampling was performed in two plant types Astragalus gossypinus and Artemisia aucheri, 120 soil samples were gathered. Experimental design was factorial design based on complete randomized design with three repeat. Five prepared treatments for Experiment were control soil, burned soil with burner and burned in oven at 100, 300 and 500 °C. Soil characteristics including the texture, saturation moisture, pH, organic matter, field capacity, wilting point, available water and retention capacity were measured in the laboratory. Results showed that percent of sand and pH increased but percent of saturation moisture, silt and clay decreased as temperature increased. On the whole, fire and heat have decreased soil potential of keeping moisture and infiltration considerably. As physical and chemical properties of soil change, especially hydrological ones, living environment of soil microorganisms and plant roots change as well. Besides, amount of runoff and erosion increases.
ALIREZA Arabameri; kourosh shirani; khalil rezai; mojtaba yamani
Abstract
landslides situation recognized using interpreting the aerial photos and extensive field measurements. Among total number of 200 identified landslides, %70 (140 landslides) of them have been utilized for model executing and %30 (60 landslides) of them for verification randomly. This research criteria ...
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landslides situation recognized using interpreting the aerial photos and extensive field measurements. Among total number of 200 identified landslides, %70 (140 landslides) of them have been utilized for model executing and %30 (60 landslides) of them for verification randomly. This research criteria including geomorphological parameters, hydrological parameters , geological parameters and environmental parameters . The Shannon’s entropy model have been used for defining the criteria weight and Area density model for defining classes weight, then the regionalization map obtained by combining the criteria and classes weight in ArcGIS 10.2 software environment and classified to 5 classes very little, little , moderate, high and very high according to natural fractures. The Roc curve have been used for model verification. The clerical accuracy results indicated that the compound model have the high accuracy 0.877 (87.7%) for identifying the regions susceptible to landslide. According to the results, slope length, slope and topography wetness index have had the most effect in occurring the landslide. Among total area of region (168547 hectar), 27.39% (46165.02 hectar) have been placed in high and very high sensitive. The prepared regionalization map can be useful for planning land use and building the infrastructure installations such as road.
Salahudin Zahedi
Abstract
The evaluation of Elymus hispidus var. hispidus ecotypes in different ecological zones of Kurdistan province was carried out at Baharestan Agricultural Research Station in order to nomination of the best ecotypes in terms of adaptability and establishment. The experiment started in 2010 and continued ...
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The evaluation of Elymus hispidus var. hispidus ecotypes in different ecological zones of Kurdistan province was carried out at Baharestan Agricultural Research Station in order to nomination of the best ecotypes in terms of adaptability and establishment. The experiment started in 2010 and continued to 2015. For each Ecotype adequate seed of different stocks in whole of the province was reaped. In reproduction phase (2010 autumn) and after soil preparation, all ecotypes were planted on plots with 5*6 m2. In 2011 and 2012autumn, the Ecotype of each Species based on complete randomized block design with 3 replications and 2 meter intervals on 2*4 m2 plots and 4 lines with 4-meter length and 50 cm intervals (In order to elimination of marginal effects) planted. The measured traits for plant selection were 1) growing 2) flowering 3) seeding 4) Yield 5) canopy cover 6) height and 7) regrowing, all data were statistically compound analyzed by SPSS and averages were compared using Duncan method. Results showed that there were significant differences among the measured traits and ecotypes (P≤0.05) in all studied years (2012-2015). In terms of measured parameters for all ecotypes of Elymus hispidus var. hispidus, Dolab Ecotype, showed superiority in the Baharestan research station conditions. it seems that altitude, soil properties and aspect factors have had most efficacy on different ecotypes operation of this specie in this study.
mahshid souri; mina bayat; Hossein Arzani; Morteza khodagholi
Abstract
Climatic factors are the most important factors affecting vegetation growth and production. The impact of each of these factors in each region varies depending on the vegetation type. The effect of climatic factors (rainfall and temperature) on the production of grazed plant species at 6 steppe sites ...
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Climatic factors are the most important factors affecting vegetation growth and production. The impact of each of these factors in each region varies depending on the vegetation type. The effect of climatic factors (rainfall and temperature) on the production of grazed plant species at 6 steppe sites in Fars province over a ten year period (1998 to 2007) was investigated. 60 plots of 2 square meters along 4 transects of four hundred meters were used to measure cover and production was measured by cutting and weighing method in 15 plots along transects. Then, using regression relationship between canopy cover (percent) and production (kg ha-1), the residual plot yield was calculated for that year. Important climatic indices analyzed in this study are: annual rainfall, growing season rainfall (March to June), plus and earlier rainfall, annual temperature, July temperature, August, maximum and minimum temperatures. The results showed that the average canopy cover was 6.3% and the average yield was 128.5 kg / ha and among the different vegetative forms of shrubs had the highest percentage of cover and production and wheat had the lowest cover and production percentage. Among the important climatic indices, annual rainfall and August temperature at all sites and the growing season rainfall at all sites except for the desired site were the most effective indicators on forage production and showed a positive and significant correlation with forage production.
Javad Motamedi; Esmaeil Sheidai Karkaj
Abstract
Species diversity is one of the important characteristics shows rangeland ecosystems changes, which isalready under effects of management practices. Thus, this research was conducted to study speciesdiversity variation and assess suitable distributive abundance model in three rangeland sites in WestAzerbaijan. ...
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Species diversity is one of the important characteristics shows rangeland ecosystems changes, which isalready under effects of management practices. Thus, this research was conducted to study speciesdiversity variation and assess suitable distributive abundance model in three rangeland sites in WestAzerbaijan. These sites were almost similar in environmental properties and differ in view point ofgrazing intensity (light, moderate and heavy intensities). After selecting sampling areas in each of thesites, species cover were recorded in 60, one square meter quadrates with 10 meter far from each otherwhich established along 100 meter transects in sites and then richness, evenness and diversity(heterogeneity) indices were calculated. Thus, rank-abundance curves were plotted and fourdistribution models such as log-normal, geometric, log-series and Brocken stick were fitted to each ofthese sites and then best model was selected in 0.05 level of confidence. Means comparison testshowed that richness, evenness and heterogeneity indices have significant differences (P<0.01) insites. Highest diversity is observed in the light grazing intensity site and lowest diversity is in heavygrazing intensity site. Species rank-abundance curves point out that low-abundance species are seenlower in light grazing site and its curve have gentler slope than moderate and high grazing intensitysites thus its diversity is higher. There is lowest species number in high grazing intensity site andevenness is lowest too due to its high number of rare and dominant species. Log-normal model wasfitted to light site implying on sustainable community and high grazing intensity site is fitted withgeometric model which point out on distractive communities with low diversity. Overall resultsshowed that implementing light grazing can protect species diversity and heavy intensity declinesspecies diversity that this shows the need considering of management on implementing light grazingintensity in the rangeland.
Nima Shakeri boroujeni; Hossein Bashari; Mostafa Tarkesh esfahani
Abstract
This study sought to develop a Decision Support System (DSS) for assisting range managers todetect range condition and make informed decisions about Feridan County rangelands. All plantspecies frequencies were measured in 31 range sites with various grazing histories using step pointmethod. Four hundred ...
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This study sought to develop a Decision Support System (DSS) for assisting range managers todetect range condition and make informed decisions about Feridan County rangelands. All plantspecies frequencies were measured in 31 range sites with various grazing histories using step pointmethod. Four hundred points along four perpendiculars 30 meters transects were measured in eachsite and grazing indicator species were identified using grazing gradient analysis. The rangeconditions of the sites were determined by evaluating the frequencies of indicator species alonggrazing gradient using Resource Environment Data Information System (REDIS). The bestmanagement practices and ecological interpretation for each range condition classes were theninserted into the REDIS model. The end users can import the indicator species frequencies of aselected site into the REDIS model and obtain the required information about range condition class,ecological information and management options. According to the results, the frequencies of sixrange species in the study area can appropriately determine range condition classes quantitatively.The model performance was then evaluated by comparing the range condition classes of 12independent sites by REDIS model and ‘Four Factors’ method. The REDIS model had an accuracyof 91 percent. The mangers can save the condition position of a selected site along a conditiongradient in REDIS model; hence they could simply monitor the range condition changes of thestudied site.
Behzad Rayegani; Gholamreza Zehtabian; Hossein Azarnivand; seyed kazem alavipanah; Sayed Jamaleddin Khajeddin
Abstract
Soil is one of the main non-renewable natural resources in the world and its degradation is considered as a major threat around the globe because it reduces the productivity capacity of soil variability and makes the environment instable in the long turn. Soil degradation has three different ...
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Soil is one of the main non-renewable natural resources in the world and its degradation is considered as a major threat around the globe because it reduces the productivity capacity of soil variability and makes the environment instable in the long turn. Soil degradation has three different aspects: Physical, Chemical and Biological degradation. If any of these aspects of the destruction of the soil can be estimated in an equation, assessment and estimation of the soil degradation can be done easily. To achieve this goal extensive efforts have been made in various parts of the world and different methods for assessing soil degradation have been suggested. In this research latest guideline of soil degradation assessment presented by Land Degradation Assessment in Aridlands is used to desert region of the east of Esfahan and different aspects of soil degradation is assessed by that. According to the findings of this research, LADA methodology of soil degradation easily can be used by most users within the country because the method is simple and provides results as fast as possible. Comparing the results of this method and photos of relative the sampling sites has shown the model is reasonably accurate.
Emad Zakeri; Mahdi Ghorbani; Ali Bozorgmehr; Hojatollah Rabani Nasab
Abstract
Current nomad settlement programs seek improving the quality of nomads’ life as their ultimate goal. However, it seems some of these programs failed due to some problems such as socio- economic problems that appear after settlement or due to the lack of proper preliminary studies before the implementation. ...
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Current nomad settlement programs seek improving the quality of nomads’ life as their ultimate goal. However, it seems some of these programs failed due to some problems such as socio- economic problems that appear after settlement or due to the lack of proper preliminary studies before the implementation. Nomad settlement program in Northern Khorasan is not an exception; therefore, identification and prioritization of problems before implementation of the program in Northern Khorasan is essential for better planning. The required data to identify and prioritize nomad settlement problems and to plan for their proper settlement were gathered through a questionnaire including the criteria and sub-criteria as well as options to solve extant challenges. The questionaire then was completed by experts and analyzed by using the analytic hierarchy process in Expert Choice2000. The results showed that cultural and social management and planning factors with coefficients of (0.433) and (0.314), respectively left the greatest influence on the failure of relevant projects in North Khorasan province. Therefore; the reform of the administrative and planning system as an important solution to problems related to the management and planning criteria and increasing the nomads’ participation in planning and management as an important solution to problems related to social and cultural criteria were assessed in present study.
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.
mohsen Naghiloo; mohamad Jafari; mohamad Tahmoures; asghar Kohandel; farinaz Hamedanian
Volume 63, Issue 1 , June 2010, , Pages 119-11
Abstract
The purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. The study area is located in west of Tehran ...
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The purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. The study area is located in west of Tehran province and southeast of Hashtgerd, next to Najm-abad village. After field studies, the index vegetation types were selected and randomized-systematic sampling method was used for soil and vegetation cover sampling in each key area. The area of each plot was determined according to type of plant species and their distribution using minimum area method. Some vegetation cover parameters such as canopy cover percentage, density and frequency of plant species were measured in the area. Then soil sampling were done from 2 horizons including 0-10 cm and 10-30 cm in each plot and soil attributes such as texture, pH, organic carbon percentage and gypsum were measured in the laboratory. Afterwards, statistical methods like multivariate regression, analysis of variance and RDA technique were used for analyzing soil and vegetation cover data. The results showed no specific difference between soil and vegetation data except for gypsum. In other word the effective factor on vegetation cover variation was soil gypsum.
Mohammad Sharifi Yazdi; Farhang Ghasriani; Mina Bayat
Abstract
The present research was done in steppic rangelands of Dehno, Kerman province to study theeffects of different harvesting intensities of Artemisia sieberi applying simulation method. Theexperiment was conducted using split plots in a completely randomized experimental designof ten replications to find ...
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The present research was done in steppic rangelands of Dehno, Kerman province to study theeffects of different harvesting intensities of Artemisia sieberi applying simulation method. Theexperiment was conducted using split plots in a completely randomized experimental designof ten replications to find the best grazing intensity. Treatments are including no harvest (as acontrol), 25, 50 and 75% harvest. In each treatment, 10 similar and average plant species wereselected as replications. All dependent variables were evaluated during the study and resultswere analyzed in SAS software. Results showed Minimum and maximum forage productionwas obtained at 25% harvest in 2008 and no harvest treatment in 2009, respectively. Regardingto the obtained results and soil condition, the 50% harvesting intensity is recommended inDehno site to maintain the vigority of Artemisia sieberi that is not dangerous for its survival,healthiness and vigority even in drought conditions.
