Majid Ajorlo; Mahboubeh Ebrahimian; Ramdzani Abdullah
Abstract
Root morphological and distribution responses of signal grass (Brachiaria decumbens) to long-term cattle grazing were examined in a tropical pasture in Malaysia. The treatments were no grazing by cattle and grazing at a moderate stocking density (2.7 animal unit/ha) under rotational grazing for 33 years. ...
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Root morphological and distribution responses of signal grass (Brachiaria decumbens) to long-term cattle grazing were examined in a tropical pasture in Malaysia. The treatments were no grazing by cattle and grazing at a moderate stocking density (2.7 animal unit/ha) under rotational grazing for 33 years. The method consists of taking soil core using a soil corer to a depth of 30 cm and extracting roots from cores by hand-washing and subsequent measuring of root morphological characteristics including length, surface area, average diameter and volume using WinRhizo Root Scanner. Root length density, mass density, surface area density, and volume density were calculated as indicators of root distribution pattern in the soil volume. Data were analyzed using repeated measure analysis of variance and independent t-test. Root diameter, length and length density were affected neither by grazing treatment nor the interaction between them (P > 0.05). Root diameters in the middle (10–20 cm) and lower (20–30 cm) soil layers of grazed site were 50% and 72% greater than that in the ungrazed site. Root volume, surface area and their densities were not affected (P > 0.05) by grazing and the interaction between grazing and soil depth. Mean root mass and mass density were affected (P < 0.05) by moderate grazing and soil depth, and the interaction between them. Mean root mass in all soil depths in grazed site was greater than that in the ungrazed site. Long-term rotational moderate grazing has no negative impact on root variables of signal grass in tropical pasture.
ali azareh; Gholamreza Zehtabian; Aliakbar Nazari Samani; Hassan Khosravi
Abstract
In management, the monitoring means systematic collection and storage of data from activities and strategies that provide assessment and report about the overall condition of the study area. In this research, among different existing methods, IMDPA model was selected for monitoring desertification in ...
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In management, the monitoring means systematic collection and storage of data from activities and strategies that provide assessment and report about the overall condition of the study area. In this research, among different existing methods, IMDPA model was selected for monitoring desertification in Garmsar plain. Based on the study area two criteria including agriculture and water were selected as the main effective criteria on desertification and desertification intensity was evaluated on the basis of seven indices including: groundwater table fluctuation, electrical conductivity, sodium absorption ratio, agricultural mention cropping pattern, agriculture yield according to land suitability, irrigation method and highly inappropriate utilization of machinery, fertilizer and pesticide chemicals. The results showed that the average weights of agriculture criterion were 2.17 and 2.27 in 2002 and 2011 respectively classified in medium class of desertification. Also, the index of irrigation method classified in very high class of desertification was the most effective factor on land degradation among studied indices in during 2002-2011. Studying the average weight of numerical value, it is distinguished that the intensity of desertification for the total area were 1.93 and 2.10 in 2002 and 2011 respectively.
M. Akbarian; S. H. Kaboli; N. Moradi
Abstract
Determining the relative sensitivity of land to erosion and its factors, could be the basis of soil conservation programs. The aim of this study is to compare water and wind erosion functions in land degradation of Dasht-e-Jeihoon using PSIAC and IRIFR.EA models and the source studying of aeolian sediments ...
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Determining the relative sensitivity of land to erosion and its factors, could be the basis of soil conservation programs. The aim of this study is to compare water and wind erosion functions in land degradation of Dasht-e-Jeihoon using PSIAC and IRIFR.EA models and the source studying of aeolian sediments in geomorphologic facieses as homogeneous units. The results indicate that in Dasht-e-Jeihoon, water erosion has been transferred fine and coarse grained sediments to the center of plain. In fact, in this region wind erosion fulfills the effect of water erosion in center of the plain. Erosion estimation shows that 50.3 percent of the region includes the mountain facieses )erosional or bare pediment (which water erosion is moderate to high, have minute to low wind erosion and 49.7 percent of the region includes the facieses of Epandage and covered pediment which water erosion is low while wind erosion has moderate to high effects. Water erosion not only results 39.7 percent of the Dashte-Jeihoon sedimentation, but also it has a significant role to supply erodible particles in downstream of the region. Observations and the results showed that for estimating the erosion in dry areas such as Dashte-Jeihoon, we need to use water and wind erosion estimator models as supplements.
Moharram Ashrafzadeh; Reza Erfanzadeh
Abstract
This study was carried out to investigate the effect of crown canopy of Ziziphus spina-christi on seed bank characteristics (density and similarity with above ground flora) in two sites with saline-alkaline and alkaline soils. In each soil, forty plots were established, half in and half outside of Z. ...
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This study was carried out to investigate the effect of crown canopy of Ziziphus spina-christi on seed bank characteristics (density and similarity with above ground flora) in two sites with saline-alkaline and alkaline soils. In each soil, forty plots were established, half in and half outside of Z. spina-christi cover. In each plot, soil sampling was done from 0-5 and 5-10 cm depths. Paired and un-paired t-test were used to compare soil seed bank characteristics between the depths, between two different soils and between in- and outside the tree canopy. The results showed that the density of seed bank in 0-5 cm depths was significantly higher than 5-10 cm depths in both soils. The density of seed in both depths was significantly higher in saline-alkaline than alkaline soils. The similarity coefficient between soil seed bank and above-ground was significantly different between under tree canopy of two soils in 0-5 cm. Soil seed density was highest under crown cover in both soils. The crown canopy of trees in dry rangelands can play an important role in reservation of soil seed bank. Therefore, the conservation of individual trees in these areas should be concerned of the managers.
yahya Parvizi; mohammad gheitury; Mosieb Heshmati
Abstract
The WEPP physically model is able to dynamically simulate runoff and soil erosion using physical concepts of erosion and hydraulic of overland flow science considering plant growth, residue decomposition, winter process. Determination of the capability of this model in runoff and erosion estimation in ...
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The WEPP physically model is able to dynamically simulate runoff and soil erosion using physical concepts of erosion and hydraulic of overland flow science considering plant growth, residue decomposition, winter process. Determination of the capability of this model in runoff and erosion estimation in different range type with investigation the effects of management were the main objectives of this research. This research was conducted in the Kabode placed across the Gharasoo watershed by installing erosion plot with dimension of 10×3 meter and three replications in three range types at the slopes of 25, 35 and 45%. Climate data including rainfall and air temperature was recorded in the site and additional data including wind velocity and direction, solar radiation and dew point temperature was prepared from Kermanshah synoptic climate station. Event based erosion and runoff was simulated in each plot by the v2008.9 version of the model. Results from model assessment for prediction of runoff indicated that the maximum model accuracy was in 45% slope. Also, mode relative error in runoff in 25 and 35% slope was about 0.61 liter. Overall, model performance in runoff estimation was sought in all three slopes, so that Nash-Sutcliff index was 0.96 to 0.73. Minimum and maximum estimation error in erosion prediction was occurred in 35 and 45% slope, respectively. Model prediction results indicated under-estimation in all the slopes. Negative amounts of Nash-Sutcliff index indicated confirms the low efficiency model especially in conditions prevailing in two slopes of 25 and 35%.
heydar ebrahimi; Alireza Moghaddam Nia; Haji Karimi
Abstract
The runoff simulation in a watershed provides insight on the processes affecting runoff generation and the stream flow characteristics like spatial and temporal variability of stream flow. This insight helps managers and planners in informed decision-makings on water resources management and planning. ...
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The runoff simulation in a watershed provides insight on the processes affecting runoff generation and the stream flow characteristics like spatial and temporal variability of stream flow. This insight helps managers and planners in informed decision-makings on water resources management and planning. The objective of this study is to compare the performances of the complex SWAT model and the simple IHACRES model for simulating runoff in the Doiraj river basin, Ilam province. For this purpose, SWAT model due to having many parameters affecting stream flow and the use of GIS, and IHACRES model due to the low and easy access data requirements, are very practical. In this study, the data over a period from 1994 to 2004 and the statistical criteria of R2, bR2, and NS were used to evaluate performances of IHACRES and SWAT models. For IHACRES model, values of R2, bR2 and NS were estimated equal to 0.34, 0.112 and 0.33, respectively for calibration period and values of 0.47, 0.235 and 0.43, respectively for validation period. In addition, for SWAT model, the coefficients were estimated equal to 0.41, 0.314 and 0.12 respectively, for calibration period and values of 0.68, 0.632 and 0.56, respectively for validation period. Final results of this study showed higher performance of SWAT model relative to IHACRES model for simulating daily runoff in Doiraj river basin and can be used to simulate runoff in the watersheds with limited data and similar natural conditions.
ّFarhad Azhir; Mohammad Fayaz
Abstract
It was necessary to detect Technical knowledge for advising culturing various plant species which share in production forage rangelands depend on region condition. Vicia subvillosa species seeds were collected from ranges around road direction Azadshahr city toward Shahrood city, on 1900 meter height ...
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It was necessary to detect Technical knowledge for advising culturing various plant species which share in production forage rangelands depend on region condition. Vicia subvillosa species seeds were collected from ranges around road direction Azadshahr city toward Shahrood city, on 1900 meter height level form sea, and planted. The goal was to introduce the suitable season and method for cultivating this species in rangeland area. Experiment was performed on Telmadare area in Posht-kooh water spreading station with 350 mm. precipitation and semi dry cold climate. Main treatments include autumn and spring, sowing date, and two subsidiary treatments seedling and planting seed, by split plot completely randomize block design in three repetition were compared. Result showed that there was a significant deference between spring and fall date cultivation, and also between two subsidiary seedlings and planting seed. Seed Germination and survival at growing period in fall season (Germination 30.50%, survival 20.97% ) compared to spring (Germination 21.50%, survival 15.33% ) and planting seed (Germination 32.61%, survival 22.39% ) compared to seedling (Germination 21.39%, survival 13.92% ) were preferred. So with Vicia subvillosa cultivation is possible to produce forage in experimental Station case, and similar climatic ecosystem area.
Hamed Eskandari Damaneh; Gholamreza Zehtabian; Ali Salajegheh; Mehdi Ghorbani; Hassan Khosravi
Abstract
In this study, the effect of land use changes on groundwater resources as well as monitoring of spatial and temporal changes of groundwater quantitative and qualitative parameters were assessed in west basin of Jazmoryan Wetland. Landsat satellite images of TM 2002 and OLI 2015 sensors by applying of ...
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In this study, the effect of land use changes on groundwater resources as well as monitoring of spatial and temporal changes of groundwater quantitative and qualitative parameters were assessed in west basin of Jazmoryan Wetland. Landsat satellite images of TM 2002 and OLI 2015 sensors by applying of Maximum Likelihood Method were used to investigate land use changes trend. Also, information related to wells in years of 2002 to 2015 was used to assess groundwater quantitative and qualitative parameters. To do this, zoning maps of spatial and temporal changes of groundwater quantitative and qualitative parameters were prepared using the best interpolation method in ArcGIS software. The results related to evaluation of the best interpolation method showed that Kriging method had the least error. According to the results of this study, the area of agricultural and urban land uses has been increased, while the area of ephemeral stream, dam, rangelands, bare and mountain land uses has been decreased in 1394 compared to 1381.These changes indicate the increased degradation as well as unstable conditions of the region that adversely affect groundwater resources. As a result of these changes, groundwater quality in southern parts of the study area has been declined. Among the factor causing this declined groundwater quality are construction of Jiroft dam on Halil-rood permanent river, lack of water right and expanded urban and agricultural lands which have caused decrease in groundwater quality over time.
Mohammad Taghi avand; Saeed Janizadeh; Mohsen Farzin
Abstract
Increasing population and agricultural development need dramatically water resources groundwater resources, therefore, are increasingly being considered, especially in arid and semi-arid regions. Aim of this research is mapping potential of groundwater resources on Yasouj-Sisakht region using data mining ...
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Increasing population and agricultural development need dramatically water resources groundwater resources, therefore, are increasingly being considered, especially in arid and semi-arid regions. Aim of this research is mapping potential of groundwater resources on Yasouj-Sisakht region using data mining method Random Forest (RF) and Generalized Linear Statistical Model (GLM). For this purpose. For this purpose, information layers including slope, slope direction, slope length, aspect, topographic wetness index (TWI), distance from fault, distance from the stream, rainfall, land use, lithology, topographic position index (TPI) and stream power index (SPI) as the main factors influencing groundwater potential were identified and developed in ArcGIS and SAGAGIS software. From the distribution of 263 springs in the area, 70% (253 springs) were used as educational springs and 30% (109 springs) were used as experimental springs. The results showed that the level of underground water with low, medium, high and very high potential in the map of the random forest was 37.78, 22.22, 18.89 and 21.11%, respectively, and in the generalization linear model were 14.49, 32.04, 31.11 and 22.36%, respectively. Moreover, Sensitivity Analysis show that the factors affecting both methods are rainfall, altitude and distance from the fault factors. The accuracy of the data mining models used in this research was also evaluated using a relative performance curve (ROC). The area under curve (AUC) for both RF and GLM models is 92% and 65%, respectively. The accuracy of RF model, therefore, mapping groundwater potential in the study area is more than GLM model.
Seyed Hasan Kaboli; حسین آذرنیوند; علی اکبر مهرابی; حسین ارزانی; سید مهدی حشمت الواعظین
Abstract
One of the conventional methods in identifying issues or making decisions in communities is considering the views of individuals of the community. The aim of this research is to determine the effective determinants of rangeland performance according to the views of range manager community in winter pastures ...
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One of the conventional methods in identifying issues or making decisions in communities is considering the views of individuals of the community. The aim of this research is to determine the effective determinants of rangeland performance according to the views of range manager community in winter pastures of the Semnan province. Analytical Hierarchy Process (AHP) as a multi-criteria/quantitative approach was employed for this research. Firstly, determinants of rangeland performance were grouped into human (economic and social) and natural (topographic conditions, climatology, geology and soils) criteria. Then, the major sub-criteria were identified based on interviews, existing experiences and literature review. Pairwise Comparison of all identified criteria and sub-criteria were conducted based on semi-structured questionnaire and interviews with 30 range managers. Finally, analysis of questionnaires was carried out using AHP method within Expert choice software. According to results, season, precipitation and private ownership seem to be the most important factors, respectively. However, research community had more disagreements regarding the natural criteria compared to human ones.
Fatemeh Azariyan; Sara Valizadeh; Pouyan Dehghan; Hassan Khosravi
Abstract
Iran is mostly consisted of arid and semi-arid areas. Rudab region, Sabzevar, is indicative of an areaexposed to and affected by the risk of desertification. This study accordingly is aimed at assessingthe risk of desertification using ESAs model, through mapping the risk of desertification. Initially,work ...
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Iran is mostly consisted of arid and semi-arid areas. Rudab region, Sabzevar, is indicative of an areaexposed to and affected by the risk of desertification. This study accordingly is aimed at assessingthe risk of desertification using ESAs model, through mapping the risk of desertification. Initially,work units’ map was prepared based on which relevant indicators were valued. Then, relevantindices were prepared based on ESAs model using GIS. Finally, ESAI index was calculated foreach work unit. After mapping the risk of desertification, desertification damages were evaluated. Itwas found out that the risk of desertification in Rudab can be classified at three classes i.e. class I,II, and III; and subclass III1 covered the biggest surface of the study area i.e. 44.48%. Based ondesertification damage map, Rudab region is divided into five classes so that class III covering35.20 percent of the area is the biggest area. Active sandy dune faces are prone to the highest risk ofdesertification since they entail significant risk factors and need to be paid due attention for desertgreening programs.
Soghra Andaryani; Mohammad Hosein Rezaei Moghadam; khalil Valizadeh Kamran; Farhad Almaspour
Abstract
Forecasting models of Land Use/ Cover changes are the main resources for managers and policy-makers in order to develop a sustainable land management plan. Changes of Orchard-lands have an effect on water resources as well as soil permeability. Thus simulation of this land use changes, in areas where ...
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Forecasting models of Land Use/ Cover changes are the main resources for managers and policy-makers in order to develop a sustainable land management plan. Changes of Orchard-lands have an effect on water resources as well as soil permeability. Thus simulation of this land use changes, in areas where there is a shortage of water resources, can provide more information about the occurred changes during a specified time scales along current management. The present study was carried out to simulate and predict the spatial-temporal changes of the orchard by 2026. For this purpose, Geomod method was used to simulate spatial changes of the orchard. Due to the lack of ability of this model in temporal simulation, Markov chain analysis method was used to solve the mentioned problem with the error proportional of 0.012. Orchard was extracted using Landsat 5, 7, and 8 satellite data after necessary corrections as well as SVM in 1987, 2000, and 2013. Then, to understand the impact of each of the criteria used to change this type of land use, instead of Delphi methods, logistic regression, Fuzzy standardization and, after all, WLC were used. The ROC index was used to validate the model. The results showed, this model has a good performance to simulate spatial changes because of area under Curve 0.91 for both of the 2000 and 2013. In the 26-years period, there are 294 hectares of orchard development, and the hybrid model showed that this land use will increase to 304 hectares till 2026
azadeh bazrmanesh; Mostafa Tarkesh; Hossein Bashari; Saeid Poormanafi
Abstract
In order to model the potential habitat of Bromus tomentellus Boiss and study the effect of climate change on the habitat of this species in Isfahan province method of modeling maximum entropy (MAXENT) were used. The species event data were determined by random categorization method using field visits ...
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In order to model the potential habitat of Bromus tomentellus Boiss and study the effect of climate change on the habitat of this species in Isfahan province method of modeling maximum entropy (MAXENT) were used. The species event data were determined by random categorization method using field visits and geographic information system including 60 rangeland locations as educational points. Also, 20 points of occurrence were surveyed using GPS in the western region of Isfahan as points of assessment. 22 environmental layers including 3 physiographic variables and 19 climate variables derived from temperature and rainfall were used in the modeling process. Using by Maxent, the relationship between species incidence and environmental factors was determined. Then, the effect of climate change using cluster variables of CCSM4 general circulation model was evaluated under two scenarios RCP2.6 (optimistic) and RCP8.5 (pessimistic) on geographic distribution of Br.tomentellus Boiss. Regarding the photo curves, the specie’s behavior relative to the environmental variables of Br.tomentellus Boiss in the range of 2500 to 3500 altitudes, slope 10 to 30 degrees, annual precipitation is 240 to 260 mm and the average temperature is 8 to 10 ° C are more likely to occur. The habitat of the species studied during the two periods of 2050 and 2070, it was observed that under the optimistic scenario, 46.1 square kilometers to the appropriate level of the habitat of the Br.tomentellus Boiss is increased and under a pessimistic scenario, about 35.74 km2 is reduced from the appropriate level of habitat of this species.
Akbarian Mohammad; Rahman Asadpour; Maryam Moslehi; Omid Zakeri
Abstract
On the coast of Hormozgan province, there are halophytic grasses distributed in coastal plain, near to the coastline. They are potential forage crops which could be used to reclamation of coastal sandy saline soil deserts. The aim of this study is introducing of suitable methods for seedling production ...
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On the coast of Hormozgan province, there are halophytic grasses distributed in coastal plain, near to the coastline. They are potential forage crops which could be used to reclamation of coastal sandy saline soil deserts. The aim of this study is introducing of suitable methods for seedling production of Halopyrom mucronatum, Aeluropus lagopoides and Sporobolus arabicus as native grasses of coastal sand masses in the eastern part of Hormozgan Province, Iran. The geographical distribution of Halo. mucronatum, Ael.lagopoides and Spo.arabicus was obtained by the help of literature review. In next stage with Referring to the field and collecting stolons and seeds of these species, seedlings were produced from cutting stolons and seeds. After planting, the percentage of produced seedlings was recorded. Using appropriate statistical tests, the best way of reproduction for each of the selected species was introduced. Test treatments were include of soaking in boiling water, soaking in acid gibberellic (1000 ppm) and stolones cuttings. Based on the results, the highest percentage growth of all three species was cutting treatment (91.6%) and the lowest percentage growth were in the control (7.9%) and treatment of gibberellic acid on seeds (0%). So that in the acid gibberellic treatment, no growth was observed. Of the three species, propagation of Spo. arabicus was more successful by stolon (100%) and seed or control method (52.4%). Based on these results, it seems that the best method for producing seedlings of these species is using stolon cuttings with 81 to 100% success.
Yadollah Bostan; ahmad fatahi ardakani; majid sadeghinia; Masoud Fehresti sani
Abstract
Attention to rangeland ecosystems is important because rangeland ecosystems have significant impacts on human agriculture and food security and also have various functions that would not be possible for humans to live without. Therefore, the purpose of the present study is to estimate the conservation ...
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Attention to rangeland ecosystems is important because rangeland ecosystems have significant impacts on human agriculture and food security and also have various functions that would not be possible for humans to live without. Therefore, the purpose of the present study is to estimate the conservation value and investigate the contribution and ranking of selected Sheikh Moussa rangeland ecosystem services through people's preferences in the form of Choice Modeling (CE). For the next study, the most important Sheikh Moussa rangeland services, including biodiversity, medicinal plants, ecotourism and artefacts, have been identified through field survey and ecosystem services separation. In order to investigate the preferences of the individuals, 170 questionnaires were distributed among the population of the Eastern Bandipur district in the 2017. The results of the present study showed that individuals' annual Willingness To Pay (WTP) to improve the status of the desired ecosystem services amounted to 66692.29 Rials ($ 2.55) and the total value of services rendered was 2667 million Rials ($ 8219.09). The results show that the variables of income, being the head of household and visiting the area are the most important factors affecting the willingness to pay. Based on the values obtained, the priority of the people of the region is to focus more on biodiversity services. Also, the value obtained by the selection test method was able to provide the contribution of each function according to Lancaster's theory. Consequently, ..
A Azarnivand; M Rabiee; H Arzani; Yones Asri
Volume 62, Issue 1 , June 2009
Abstract
With respect to wide distribution of A. sieberi Besser in Iran, various studies have been done on its habitats and different ecological properties have been referred as effective factors in establishment of this species. In this research, we tried to study the ecological range of A. sieberi and its ...
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With respect to wide distribution of A. sieberi Besser in Iran, various studies have been done on its habitats and different ecological properties have been referred as effective factors in establishment of this species. In this research, we tried to study the ecological range of A. sieberi and its relationship with vegetative characteristics. Therefore, climate properties including annual precipitation, number of days with precipitation, annual, minimum and maximum temperature, absolute minimum and maximum temperature; topographic property including altitude; edaphic properties including pH, EC, SP, texture, lime, gypsum, C, Na, K, Ca, Mg, N and P; and vegetative characteristics including large and small diameter of canopy, height of plant and diameter of most thickness branch were measured in 34 populations. For determination of ecological range, normal curve with histogram of frequency have been drawed for total properties. All populations divided in 3 groups by cluster analysis. Measured properties compared by analysis of variance between 3 groups. The significant properties were: average of annual, minimum and maximum temperature, absolute minimum and maximum temperature, large and small diameter of canopy and height of plant in 0.1 % probability level, altitude and C in 1 % probability level, while annual precipitation, number of days with precipitation, N, P and Na in 5 % probability level.
Pouyan Dehghan; Hossein Azarnivand; Hassan Khosravi; Gholamreza Zehtabian; Alireza Moghaddam Nia
Abstract
The excessive reducing capacity of natural resources is one of the most important challenges that human beings have faced it in the last century. Proper land use and land use management based on its ecological potential play an important role in achieving sustainable development. Hence, in order to achieve ...
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The excessive reducing capacity of natural resources is one of the most important challenges that human beings have faced it in the last century. Proper land use and land use management based on its ecological potential play an important role in achieving sustainable development. Hence, in order to achieve sustainable development and in order to use land appropriately, tendencies should be directed towards the planning and utilization of resources on the basis of their resources. Therefore, since agriculture has a great deal of environmental impact on urban areas, the evaluation of agricultural lands is necessary. The aim of this study is evaluation of ecological potential of land in Eshtehard in terms of agriculture and rangelands. For this purpose, the ecological potential of the lands of Eshtehard was evaluated using ecological criteria and using Fuzzy, Fuzzy AHP methods and Geographic Information System (GIS). The Fuzzy method was used to standardize the layers and also to assign weight to each of the indices used by Fuzzy AHP method. The results of this study showed that class 1 lands with 1.50% is the lowest and the class 4 lands with 25.36% of the total area of the study area has the biggest area. The results of the analysis in this study indicate the high efficiency of Fuzzy AHP method in assessing the ecological potential of the area and can be used with changes necessary for other areas and also other location actives.
Sh Hakimkhani
Volume 63, Issue 1 , June 2010, , Pages 13-27
Abstract
By determining relative importance and contributions of erosion types to sediment yield, erosion susceptible areas in a watershed will be identified, and sediment control and soil conservation projects can be focused on that areas. Because of many problems associated with traditional procedures for identifying ...
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By determining relative importance and contributions of erosion types to sediment yield, erosion susceptible areas in a watershed will be identified, and sediment control and soil conservation projects can be focused on that areas. Because of many problems associated with traditional procedures for identifying sediment sources, fingerprinting techniques, based on physical, chemical and organic properties of sediment and source materials, are increasingly being used as valuable and effective approach to assemble such information. In this method, a suitable composite (set) of diagnostic properties and a multivariate mixing model are employed to estimate the relative contribution of sediment sources to sediments transported to basin outlet. In this study, using suitable composites of geochemical elements, radionuclides, organic Carbon, Nitrogen and Phosphorous, capable of discriminating two groups of erosions (namely, sheet and rill erosions, and gully, channel and river bank erosions) of the study basin, and a multivariate mixing model were used to determine contributions of that erosion types to sediment yield. The suitable composite fingerprints (elements) were obtained using discriminant analysis. The study basin is Ghara aghaj basin, located in Makoo township, West Azarbaijan province. The suitable composite fingerprints having capability to distinguish the above mentioned erosion types include, 137Cs, OC and Nb. Mean contributions from the two main erosion types, namely sheet and rill erosions, and gully, channel and river bank erosions were estimated as 34.6% and 65.4% respectively. Low mean absolute errors (less than 12%) showed high degree of correspondence between measured and predicted properties. High model efficiencies (greater than 0.99) confirmed the goodness of fit of the mixing models. Also it is argued that fingerprinting estimates for sediment sources are consistent with field observations.
Nafise Panahi; amirhossein hamidian; Ali Tavili
Abstract
This study was conducted in Halgheh Darreh waste disposal site in Karaj in order to determine theconcentration of Ni and Pb in Halimocnemis pilifera and in region’s soil. Three 50*50 m plots inthe direction of the prevailing wind were selected. The First plot was close to the leachate pondsand ...
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This study was conducted in Halgheh Darreh waste disposal site in Karaj in order to determine theconcentration of Ni and Pb in Halimocnemis pilifera and in region’s soil. Three 50*50 m plots inthe direction of the prevailing wind were selected. The First plot was close to the leachate pondsand the next two plots were located at 500 and 1000 m from the first plot, respectively. Ten randomsamples from root and shoot of the plant and also from the soil were collected. The concentrationsof the metals were determined using a flame atomic absorption spectormetery (AA 240 (FS) VarianCompany, USA) after dry acid digestion. Two-way and one-way ANOVA were used to assess thedifferences of metal concentrations in roots and shoots of the plants, and in the soil of the plots,respectively. Duncan Test was applied to compare the average concentrations of metals in differentplots. The results revealed that the soil of the different plots do not have a significant difference inNi and Pb concentrations. No significant difference was observed between the metal concentrationsin roots and shoots of the plants. The plants in the second and third plots showed to have the highestconcentration of Pb (3.27 mg kg-1) and Ni (4.41 mg kg-1), respectively. Bioconcentration andtransmission factors for Ni and Pb (TF=1.21; 0.75 and BCF=1.11; 0.29, respectively) suggested thatH.pilifera is an appropriate plant to remove Pb and Ni from soil.
ّFarhad Azhir
Abstract
Knowledge of livestock grazing behavior is one of factors of optimal and sustainable rangeland management. For optimal management of mountain rangelands, a study was conducted in the rangelands of Lavash. This is located in the Central Alborz Protected Area, and grazed by native hybrid cows. Measuring ...
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Knowledge of livestock grazing behavior is one of factors of optimal and sustainable rangeland management. For optimal management of mountain rangelands, a study was conducted in the rangelands of Lavash. This is located in the Central Alborz Protected Area, and grazed by native hybrid cows. Measuring the vegetation characteristics of the rangelands those areas with 30 plots of 1 × 1 square meter, in three survey strips parallel transects with a distance of 50 meters from each other's, and a length of 100 meters in 2018 and 2019. According to the obtained results, the amount of forage consumption was almost twice of what was range capacity. The preference value of most of the studied species was estimated between 32 and 35% by weighing usage forage method. Palatability category and grazed time percent of each plant species was determined by using camera recording. Plant distribution on rangeland and plant cover percent effected on grazed time percent in the last month during grazing season. Hybrid cattle had unique desire to breed most of the species except for three species belong to Poaceae, Bromus tomentellus, Alopecurus textilis and Hordeum brevisubulantum which were considered more palatable. To calculate the weighted average percentage of preference value of each plant type, rangeland manager could be choose a range of decisions about each of the plant species indices include: range production, plant coverage percentage, and plant density, according to the type of vegetation type, the importance of the role of each plant species and other environmental conditions.
mohsen padyab; Sadat Feiznia; Hasan Ahmadi; Ardeshir Shafei
Abstract
Evaluation of changes present in soil and water resources due to operation implement of floodwater spreading is necessary to assess their positive or negative resultant effect. Rate of the internal sediment to diversion spreader channels, surface sedimentation and aggregation of the spreading field depth ...
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Evaluation of changes present in soil and water resources due to operation implement of floodwater spreading is necessary to assess their positive or negative resultant effect. Rate of the internal sediment to diversion spreader channels, surface sedimentation and aggregation of the spreading field depth are most important effective attributes on the yield of floodwater spreading systems. These factors can change physical and chemical properties of studied field, as, by measuring of the infiltrate depth sedimentation of can achieve influencing depth of floodwater. To determine the effect of flooding spread on the sediment infiltrate rate in the field depth of Gachsaran floodwater spreading, from 0-15, 30-15, 30-45 and 45-60cm of the soil surface of spreading field and control were sampled. Granulometry of all samples was done using dry sieve and hydrometric analysis and then percent of the sediment grains with size of less than two millimeters were subjected to analysis of variance (ANOVA) by Duncan t-student test for 80 sampled samples. Results showed that deep entering of the sediments into drilled profiles to 30-45cm was completely distinct which can affect on the soil physical and mechanical properties. However, after the 30-45cm depth, the impact of floodwater spreading was minimal. The infiltration of each studied layer is the most important feature which will change from surface to the depth of spreading belts, so that by increasing infiltrated fine particles in the depth and blocking pores, the soil layers are clogged and in result reduce the infiltration rate, sharply. This state was more remarkable in the spreader belts surface. Furthermore, by depositing the sediments in the surface (0-15cm depth), an impermeable and earthen layer is created which prevent from infiltrate the particles and even water into soil depth. Generally, with determine of the deposited sediment level in the spreading belts and also its deep infiltrate rate can provide effective and practical decision to improve efficiency and easy maintenance of the floodwater spreading systems or even not use this method.
Fazel Amiri; Hossein Arzani
Abstract
Range inventory is the recognition and evaluation of potential and actual production in order of optimal utilization of this valuable natural resource. Determination of range suitability for medical and industrial plants, considering sustainable utilization and creating models for medical and industrial ...
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Range inventory is the recognition and evaluation of potential and actual production in order of optimal utilization of this valuable natural resource. Determination of range suitability for medical and industrial plants, considering sustainable utilization and creating models for medical and industrial plants use in Ghareh Aghach of Semirom watershed by FAO (1991) and GIS, was the main objective of this research. Determination of range suitability for medical and industrial plants use, in Ghareh Aghach of Semirom watershed based on a method suggested by FAO and GIS was the main objective of this research. Two criteria’s of vegetation cover and accessibility to water resources were integrated to determine suitability model of medical and industrial plants on rangeland. In vegetation cover criteria, the samples were randomly collected along 3 two hundred meter transects in each vegetation type. Vegetation cover percentage, composition, abundance, and the presence or absence, diversity, production, application and consumption of medicinal plants and industrial were measured using 1m2 quadrates. Accessibility to road and slope determine and by integrating these two criteria, suitability maps based on FAO method were prepared. The results showed that from 7158.69 hectares of study rangelands, 3.69% ha (0.05%), 1761.1 ha (24.6%), 3217.7 ha (44.95%) and 2176.17 ha (30.4%) of the area were classified to S1, S2, S3 and N suitability classes for medical and industrial plant utilization.
Iman Islami; Ali Akbar Mehrabi; Gholam Reza Zehtabian; Mehdi Ghorbani
Abstract
Agriculture sector is the main consumer of water in the world. In productive sectors likeagriculture, water is considered as a valuable mediatory commodity or production input.Demand for agriculture water comes from consumers› (agriculture products›) behavior. Thisstudy aims to evaluate ...
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Agriculture sector is the main consumer of water in the world. In productive sectors likeagriculture, water is considered as a valuable mediatory commodity or production input.Demand for agriculture water comes from consumers› (agriculture products›) behavior. Thisstudy aims to evaluate water use optimality in Pomegranate Arbors at the Charkhab village inthe Yazd province. The data was randomly collected from 95 people of 153 beneficiaries inthe study area. This study surveys water demand variations in the case of one percent changein water procurement expenses in Yazd. Elasticity estimation revealed that pomegranateproducers› sensitivity to agriculture water price changes is high. To be specific, one percentincrease in the price of agriculture water would decrease water demand by 24.32 percentamongst pomegranate producers in Yazd. Production elasticity of water input was obtained0.0565 which is located in the third part of production region and means over-consumption ofwater by producers due to its low price. Given high demand for water in this arid area havingappropriate polices in water pricing for optimal water consumption is needed.
Mohammad Reza Sarvati; Kazem Nosrati; Shima Hassanvandi; Babak Mirbagheri
Abstract
Landslides and slope instabilities are major hazards for human activities often causing economiclosses and property damages. Sikan River Basin (Ilam province) due to the topography, tectonic,lithology, and climate has enough potential for occurrence of this phenomenon. The objectives of thisstudy were ...
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Landslides and slope instabilities are major hazards for human activities often causing economiclosses and property damages. Sikan River Basin (Ilam province) due to the topography, tectonic,lithology, and climate has enough potential for occurrence of this phenomenon. The objectives of thisstudy were to determine effective parameters controlling the landslide occurrence and to preparezonation map of landslide risk in Sykan River Basin. In view of this, 11 geophysical characteristicsincluding (height, slop, slop direction), geomorphologic (the slop of land surface), geology (lithology,the distance from the fault), hydrography (the distance from the river), coverage, land use (land useand the distance from road, the distance from village), pedology (soil texture), and dependent variable(landslide distribution) were selected an independent variable and were analyzed using logisticregression model. The results showed that the influential factors on landslides occurrence in the basinare the distance from river, land use, the distance from village, the materials (lithology), slope, and theshape of land surface. Finally, the study area was classified into five major area based on landslideoccurrence risk which 19.1 km2 of total area had very low risk, 15.9 km2 had low risk, 14.9 km2 hadaverage risk and 14.6 km2 had high risk and 9.1 km2 had also very high risk. The model evaluationshowed a high accuracy 74.2% in the study area. The results of this study can be useful for landsliderisk management and for controlling the accelerated parameters.
Ataollah Ebrahimi
Abstract
Canopy cover and forage production have always been two important indicators in rangeland assessment, which sometimes are applied as surrogates of each other. These two indicators are widely used in rangeland studies and have a vital role in evaluation of rangeland structure and functions. Occasionally, ...
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Canopy cover and forage production have always been two important indicators in rangeland assessment, which sometimes are applied as surrogates of each other. These two indicators are widely used in rangeland studies and have a vital role in evaluation of rangeland structure and functions. Occasionally, different sampling groups (estimators) evaluate forage production and canopy cover of different spaces and times. This research was aimed at investigation of different sampling groups and life-forms' effects on relationship between canopy cover and forage yield estimation. To do so, the impact of three sampling groups and five life forms (Fixed factors) on estimation of relationship between canopy cover (covariate) and forage yield (dependent variable) in a full factorial model in rangeland of Chahrtagh of Naghan, Chahrmhal-va-Bakhtiari Province, was estimated. Results shows that predictor variable of canopy cover is a god surrogate for forage production (P≤0.05) of different life-forms, but different sampling groups significantly (P≤0.05) effects on relationship between canopy cover and forage production estimation. Nevertheless, different life-forms do not significantly (P≤0.05) influence estimation of canopy cover and forage production relationship. By the way, interaction between sampling group and life forms considerably (P≤0.05) affects the relation. Therefore, we conclude that, although, the canopy cover is a good predictor of forage production, nonetheless, different sampling groups should not be engaged in sampling and monitoring vegetation cover and forage production estimation, specifically, if estimation of different life-forms' production is intended.
