sahar Aryaeefar; Abolfazl Tahmasebi; Majid Mohammad Esmaeili; Ali Rahemi Karizaki
Abstract
Atriplex leucoclada Boiss is one of the most important native species of dry and semi-arid rangelands in Iran which is faced to low germination and seed dormancy. In order to investigate the effective methods of breaking dormancy of this species, an experiment was conducted in a completely randomized ...
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Atriplex leucoclada Boiss is one of the most important native species of dry and semi-arid rangelands in Iran which is faced to low germination and seed dormancy. In order to investigate the effective methods of breaking dormancy of this species, an experiment was conducted in a completely randomized design with eight treatments including scarification treatments 100 and 200, hypochlorite: at 5, 10, 15, 20, 25 minutes, boiling water treatment: submerging seeds in boiling water for 1, 5, 10, 15, 20, 25 minutes, wet chilling : putting Seeds in a refrigerator at 4 ° C and continuously wet at intervals of 1, 2, 3, 4, 5, 6, 7, 8 weeks, Sulfuric acid treatment: Seeds in Sulfuric Acid 98% Diets: 5 seconds, 30 seconds, 5, 10, 15, 20, 30 minutes, Seeds Dry chilling: in a refrigerator at 4 ° C at intervals of 1, 2, 3, 4, 5, 6, 7, 8 weeks, and Seed burial treatments were carried out in four replications in two laboratory sections (petri-dish cultivation) and cultivation was done in a pot. In the laboratory section, no significant results were obtained, but in the culture, results of data analysis indicated that 25 min hypochlorite treatment had the highest rate of germination and 100 mg treatment and hypochlorite treatment of 25 minutes had the best effect on seed dormancy.
Omid Asadi Nalivan; Seid Saeid Ghiasi; Sadat Feiznia; Narges sagghazade
Abstract
At present, Groundwater contamination by nitrate, serves as one of the most important environmental issues. In respect to various land uses of Silveh basin, its ground water quality parameters might vary spatially and temporally. For this, ground water samples taken from 145 points were evaluated. After ...
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At present, Groundwater contamination by nitrate, serves as one of the most important environmental issues. In respect to various land uses of Silveh basin, its ground water quality parameters might vary spatially and temporally. For this, ground water samples taken from 145 points were evaluated. After determining nitrate spatial variations by varyogram, different methods involved distance inverse method and geo-statistics methods of radial estimator approaches, local estimator, ordinary kriging, simple kriging and global kriging were evaluated using GIS software and nitrate spatial distribution map were prepared in two time intervals (pre and post-harvest). Criteria based on the Root Mean Squared Error(RMSE), ordinary kriging method has the lowest error, and the accuracy considerably. Spatial distribution of nitrate in area groundwater indicated that there was high concentration of nitrate in land uses of agriculture and arid area. Of course, presence of shale-stone causes nitrate releases, intensifying issues. Comparison of nitrate samples concentration with national and international standards suggested that 1.38%(2 Point) of all samples have been nitrate-contaminated before harvesting, while 11.03%(16 Point) of them have been contaminated after harvesting.
hamed eskandari; moslem borji; Mehdi Ghorbani
Abstract
Local initiatives have been defined as specific collective activities without external support or incentives in order to control either ground or surface waters. One of the most important of approaches in water resources management is community-based water management. Social structures of water resources ...
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Local initiatives have been defined as specific collective activities without external support or incentives in order to control either ground or surface waters. One of the most important of approaches in water resources management is community-based water management. Social structures of water resources are one of the aspects of indigenous knowledge in the management of water resources and it is necessary to analyze the social structures associated with it. The main objective of this paper is to identify aspects of indigenous knowledge related to the sustainable water resources management in Roozkin Village - Sarduyeh- Jiroft County. In this study, based on anthropological methods and qualitative approaches, including direct and participatory observation and organized interviews with 32 informed respondents (farmers) was used. In Roozkin Village, a certain social structure governs on the management of water resources in the region dating back more than 100 years. Cooperation in water resources management is considered as fundamental principle in this village and the social roles of Arbab and Zaim are among social initiatives of this village in management of water resources. In this village, 10 associations or local groups have been formed for managing water resources and each group is composed of Arbab and Zaim. In general, it could be noted that indigenous knowledge and local traditions in the village are factors influencing on sustainability of water resources and also it could be concluded that they will be effective in the promotion of socio-ecological resilience in the face of environmental crises such as drought.
Fatemeh bahreini; Fatemeh Panahi; Mohammad Jafari; Arash Malekian
Abstract
The complexity of drought phenomenon hinders our full understanding of its impact. Field sampling, Geographic Information Systems, SPI and NDVI, EVI and SAVI indices derived from 16-day interval MODIS images during 2000-2015 were used to better understand the effects of drought on vegetation In recent ...
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The complexity of drought phenomenon hinders our full understanding of its impact. Field sampling, Geographic Information Systems, SPI and NDVI, EVI and SAVI indices derived from 16-day interval MODIS images during 2000-2015 were used to better understand the effects of drought on vegetation In recent study, ground true map was prepared by sampling and field surveys and vegetation cover data was obtained from 32 sampling units in 320 plots over the entire study area. Then, the correlation between field sampling data and vegetation indices was estimated and vegetation cover models were produced for different indices. In this study, precipitation data of 14 stations within and around the study area were used and SPI was calculated at the same time scales with the vegetation indices to study the effect of drought on vegetation. The results showed that NDVI has had the highest correlation coefficient (R2=0.56) amongst the indices so it was selected for vegetation cover percentage mapping. Investigating NDVI rates and drought index in different temporal periods, 9-month SPI was found to have the best correlation with NDVI. On the basis of SPI analysis, it was found that the study area had the most severe drought in 2012 and the best wet condition in 2004. The similar trend was observed in NDVI. The comparison of classified images between 2004 and 2012 (with 42 % changes in poor vegetation) indicates the effect of drought on vegetation in the study area.
saeid barkhori; rasol mahdavi; gholamreza zehtabian; hamid gholami
Abstract
The overuse of fossil fuels, population growth and other factors have caused evident changes in the Earth climate. In this study, HadCM3 model was used to evaluate changes in the variables of precipitation, minimum and maximum temperatures at Jiroft plain in future periods. Afterward, climatic variables ...
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The overuse of fossil fuels, population growth and other factors have caused evident changes in the Earth climate. In this study, HadCM3 model was used to evaluate changes in the variables of precipitation, minimum and maximum temperatures at Jiroft plain in future periods. Afterward, climatic variables was simulated by the LARS-WG model in the periods of 2011-2030 (horizon 2020) and 2046-2065 (horizon 2055) under three scenarios of A1B, A2 and B1. The results showed that the highest amounts of minimum and maximum temperatures will occur based on three scenarios A1B, A2 and B1 in the horizon of 2055. By comparing the average of the monthly minimum and maximum temperatures in the base period (1989-2010) and future periods (under the scenarios of A1B, A2 and B1), the average temperature will increase in the most months of the year. During the scenarios of A1B, A2 and B1, the most annual precipitation will occur in the horizon of 2020. The average amounts of monthly precipitation will increase in the months of January, August, September, October, November and December and will decrease in the other months. Comparing long-term annual precipitation shows that the lowest amount of precipitation will happen under the scenario of B1 and during the period of 2046 to 2065. However, the most precipitation will happen under the scenario of A1B and during the 2011-2030 period.
mina bayat; Hossein Arzani; adel jalili; hassan ghalij nia
Abstract
In this study the effects of three important factors: the climatic precipitation, temperature and relative humidity on the amount of canopy cover and forage production in a period of five years (1381-1385) and 1392 in semi-steppe rangelands Reineh and Polur in the Mazandaran province studied. The statistical ...
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In this study the effects of three important factors: the climatic precipitation, temperature and relative humidity on the amount of canopy cover and forage production in a period of five years (1381-1385) and 1392 in semi-steppe rangelands Reineh and Polur in the Mazandaran province studied. The statistical models (simple and multiple regression) to find the relationship between various forms of vegetative cover and annual forage plants using climate variables in different periods of time with Minitab.14 and Excel software was used for data analysis. The results of six years of study in a semi-steppe rangelands Polur and Reineh showed an average canopy cover of 51 percent and the average yield was 372 kg per hectare. The total vegetation cover of Rineh pastures had the most relation with a total rainfall of the growth season and the March and the average temperature. The temperature was more effectively than rainfall in annual yield. And The yield affected by July temperature. The total vegetation cover of polur had not significant relation with climate factors but each of the vegetation form in Different time base had significant relation. The total grazing species yield of plour affected by growth season rainfall. So instead of one year measurement of vegetation cover and production can be estimated the production and vegetation cover fluctuation according to climate parameters. With long-term vegetation cover and production data, can be determined the available forage and pasture capacity to prevent the range degradation.
Mohammad Ali Zare Chahouki; mahbobe abbasi
Abstract
Rheum ribes species is one of the important medicinal plants in the world. In this study were used maximum entropy method (Maxent) and the MAXENT software to this prediction habitat map. Measure environmental variables was soil variables including gravel percentage, pH, electrical conductivity, percent ...
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Rheum ribes species is one of the important medicinal plants in the world. In this study were used maximum entropy method (Maxent) and the MAXENT software to this prediction habitat map. Measure environmental variables was soil variables including gravel percentage, pH, electrical conductivity, percent lime, gypsum, organic matter, soluble salts (Ca+, Na+, K+, Mg2+, CL, HCO3, SM and SO2), sand, clay and silt and variable topography (slope, aspect and elevation) and rainfall variable. Those were effective variables on the presence of species. The model classification accuracy using the area under the curve (AUC) was 95% (good Level), and kappa coefficient was obtained 0.92 that measuring from the agreement of prediction maps with ground truth, which is at a high level. The results of this study showed that the habitat of this species is in the soils with low pH (less than 8), clay Low (less than 40%), coarse texture and organic matter more than 4.0 percent. And the presence of this species has inverse relationship with a pH of both the depth and the clay first depth and with has directly relationship to organic matter of both depths.
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 Hamidreza Sadeghi; Zahra Hashemi Ariyan; Mehdi Vafakhah; Zeinab Karimi
Abstract
Studying temporal and spatial variations of soil erosion and the effective factors is very important for providing appropriate solutions to properly plan the utilization of watershed resources. However, few studies have attempted to examine temporal and spatial variations of soil erosion. In this study, ...
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Studying temporal and spatial variations of soil erosion and the effective factors is very important for providing appropriate solutions to properly plan the utilization of watershed resources. However, few studies have attempted to examine temporal and spatial variations of soil erosion. In this study, the temporal variability of spatial participation of soil erosion has therefore been investigated in the Gonbad representative and treated watersheds in Hamedan Province with an area of 300 ha. For this purpose, the work units were designated through overlaying land cover type, soil texture, and slope maps. The soil erosion was then measured in each work unit using rainfall simulator with intensity of 50 mmh-1 during 30 minute in two main rainy months of November and October 2014. Then, three points with relatively similar characteristics and representing each work unit were determined in the specific outlines of the equilateral triangle. The soil erosion was consequently measured with five minutes interval after the beginning and ending of rainfall simulation. The results of analysis of variance verified a significant difference (P<0.01) among different work units in soil erosion in both representative and control watersheds verifying spatial variation of different parts of the watersheds in soil erosion and consequent sediment yield. While, no significant difference was found using t-test between soil erosion during November and October 2014.
Azam Tayebi; Mohammad Faraji; Shahram Yousefi khanghah
Abstract
This study with purpose analysis the effect of Maroun՚ dam construction on land use changes using Landsat satellite images taken. For this study two The Landsat satellite image of in 16-year period (1999-2014) and maps Topography was used by applying geometric and atmospheric correction. Then using ...
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This study with purpose analysis the effect of Maroun՚ dam construction on land use changes using Landsat satellite images taken. For this study two The Landsat satellite image of in 16-year period (1999-2014) and maps Topography was used by applying geometric and atmospheric correction. Then using the software ENVI maximum likelihood supervised classification land use map to 7 ClassesRiver, Rangeland , Agriculture, Woodlands and gardens, villages, Palms and Bayer, respectively, with an Kappa coffecient of 75% and 86% were classified . Results classified maps years (1999- 2014) showed that during this period due to dam construction, Agricultural lands, Woodlands and gardens, Village, Palms, Rangeland , increased area and River and Bayer levels was reduced. So by comparing the studing periods of use map, the map changes, represents the maximum land use changes, Agricultural conversion to Rangeland is the equivalent 2875/270 hectares, the lowest changed into Bayer to the village with an area of 0/19 hectares. Overall findings showed that the establishment of Maroon Dam improves the user in the region. Therefore, investigation account the cost of building the dam, construction of the dam has been a lot of positive effects, and in the long run lead to positive economic growth in the region . Changes in cross-river bed also shows that in 1999 the average width bed, 106/10 meters but in 2014 115/89meters and an average of about 7/79 Kilometers been reached. These changes represent a reduction of width and curvature of the river was in 2014.
Seyed Hasan Kaboli; Farhad Fakhri; Ali ashraf Jafari; Parviz Bayat
Abstract
Different plants have different effects on the characteristics of their surroundings, especially on the soil. Soil properties also have the different effects of these plants on them. In this research, the effect of capparis spinosa on the soil characteristics of three areas with different soil characteristics ...
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Different plants have different effects on the characteristics of their surroundings, especially on the soil. Soil properties also have the different effects of these plants on them. In this research, the effect of capparis spinosa on the soil characteristics of three areas with different soil characteristics was evaluated. The under-floor soils of the capper plant in three depths of 0-30, 60-30 and 60-90 cm, compared to the non-vegetation soils, were taken in three different geographic regions with six replicates and a total of 108 depth samples, and in The laboratory measured some of their physical and chemical properties. SPSS software was used to analyze the data and to compare the measured characteristics with non-pairs F and T tests. The results showed that the effect of capper plant on the characteristics of saline soils is a significant reduction of salinity and soil salts, reducing SAR and simultaneously improving some of the characteristics of fertility, such as increasing the potassium available in these areas. Also, in soils with light and medium non-saline texture, significant increase in available potassium levels and SAR reduction were observed in the lagging soil.
Mohsen Farzin; saeideh menbari
Abstract
Karstic water resources are one of the most important sources of water for the world's population, which accounts for 25-20% of the world's population; these resources are subject to increasing pressure and require special management due to the nature of the point recharges. In this research, after mapping ...
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Karstic water resources are one of the most important sources of water for the world's population, which accounts for 25-20% of the world's population; these resources are subject to increasing pressure and require special management due to the nature of the point recharges. In this research, after mapping vulnerability and zoning protection on karstic aquifer of Tange-Konara Yasuj using COP method, proposed restrictions was presented. At first, the geological and topographic maps of the area to transfer to GIS software were digitized. In order to provide data, maps, and information about the situation of karstification, soil, and vegetation field surveys was conducted multiple times. Then, the operations and mathematical calculations to mapping of factors and sub-factors considered in COP method, was conducted in GIS media. The results show that karstic aquifer vulnerability rate changes 0.6 to 4.2 which showing high to very low vulnerability for the study area; So that, high, moderate, and low vulnerability classes are on Quaternary, Asmari, and Pabdeh-Gurpi-Razak formations, with 1.6, 77.1, and 21.2 percent of the area, respectively. The importance of each of the factors in determining the sensitivity of the aquifer in the study area can be considered as P> C> O. Finally, three protection zone was considered including I for areas with high vulnerability, II for areas with medium vulnerability, and III for areas with low and very low vulnerability that was presented in the form of a protective map.
abbas ali ghezelsofloo; Mahboobeh Hajibigloo
Abstract
Estimation of suspended sediment basins of data and information is readily available but for basins without statistics, other methods require. The experimental method known as sediment rating curves or relationship "discharge sediment load" is provided. This study seeks to provide better separation of ...
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Estimation of suspended sediment basins of data and information is readily available but for basins without statistics, other methods require. The experimental method known as sediment rating curves or relationship "discharge sediment load" is provided. This study seeks to provide better separation of data and the preparation and suspended sediment curve refine hydrometric stations Maraveh Tape, Houtan, Qazanqayeh on the Atrak River in the Atrak watershed is located in Golestan province. To increase the accuracy of the classification scale monthly, quarterly, all samples, wet and dry periods and classifieds sediment discharge with frequency curve fitting techniques to fit a linear, linear fit by adjusting FAO, fitting combination (multi-line ), graphical approach (maximum concentration) and is fitted intermediate categories. For this purpose, statistical indicators were used to select the top. The results showed that sediment rating curve model by fitting a line to the correct application of FAO data Maraveh Tape station, method fitting a line dividing adjusted by applying FAO data on dry and wet period in the station Qazanqayeh and method Fitting a line segmentation classification data on discharges in Houtan Station Among the models tested with the least amount of mean square error and the predictability of the study is to estimate precipitation stations. Selected on the basis of the average amount of sediment suspended for watershed Atrak to Maraveh Tape station, Qazanqayeh and Houtan respectively 705, 683 and 781 Ton/Km2.day was estimated.
Elham Kianisalmi; Ataollah Ebrahimi
Abstract
Wetland meadows as a natural ecosystems plays an important role on sustainability of nature, although are enormously under drainage and changing in the recent years. Shahrekord meadow, which is located adjacent to the city, considered as a natural heritage due to its contribution to tourist visiting, ...
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Wetland meadows as a natural ecosystems plays an important role on sustainability of nature, although are enormously under drainage and changing in the recent years. Shahrekord meadow, which is located adjacent to the city, considered as a natural heritage due to its contribution to tourist visiting, balancing weather in addition to supplying forage for animals. However, this meadow is declining due to anthropogenic effects that this article aims at studying and evaluation of its change and prediction of future condition using Landsat TM5, ETM+7 and OLI/TIRS. To do so, first of all the images of 1987, 1994, 2001, 2010 and 2016 were gathered, then radiometric and geometrically were evaluated. After that, landuse/landcover of the study area was depicted using a maximum likelihood method in TerrSet (Ver. 18.31). Afterward, change detection of the study area was done using a cross-tabulation method and the future condition was predicted using a CA-Markov model. Results indicated that a significant change was occurred in this study area whereas in 1987 whole of the study area was covered by meadowland but land cover changes altered this valuable ecosystem to constructed area (3.33%), arable land (25.02%) and airport (19.65%) in 2016. Results of change prediction also depicted that 5.08% of the study area will be converted to other land cover in 2026. Therefore, we recommend that land use and land cover of this valuable ecosystem should be conserved due to the function and services that this meadowland offered.
ayoub moradi; Ali Nakafinejad; Majid Ownagh; Choghi Bairam Komaki; mehrangiz foladi mansouri
Abstract
Indiscriminate land utilization methods, forest and rangeland degradation, land abandonment and development of residential areas contribute to the changes in flow intensity, erosion rate and sedimentation. Therefore, having knowledge on the effect of land use changes on discharge flow and sediment yield ...
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Indiscriminate land utilization methods, forest and rangeland degradation, land abandonment and development of residential areas contribute to the changes in flow intensity, erosion rate and sedimentation. Therefore, having knowledge on the effect of land use changes on discharge flow and sediment yield has been found necessary. The present research aims at investigating the effects of these factors by means of the semi-distributed Soil and Water Assessment Tool (SWAT) in Galikesh watershed, Golestan province (as a tributary of the River Gorganroud), in an area covering approximately 39000 hectares. This model was used in a 27-year period for simulation, calibration, validation and optimization of the parameters affecting flow and sediment yield. Land-use maps were prepared form the Landsat imageries dated 1987, 2000 and 2013. The SUFI2 model was used for model calibration and validation. Nash-Sutcliffe (NS) index was used as the objective function during model calibration (1990-2007) for the simulation of discharge and suspended load, which resulted in 0.63 and 0.61 that could be interpreted as satisfactory compared to the standards set in previous research. To evaluate the effect of land use changes on runoff and sediment yield, all model inputs, other than land use, were assumed constant. The results demonstrated that land use changes since 1987 to 2013 have led to an increase in annual runoff height by 1.40 mm and annual sediment concentration by 2 t.ha-1.
TAYYEBEH MESBAHZADEH; nahid alipour
Abstract
Dust phenomenon is one the problem that is developed due to human interference and unreasonable utilities from natural resources and their destruction. In this review, the dust phenomenon frequency was done using selected synoptic stations statistical in Alborz and Qazvin provinces during 2000 to 2014 ...
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Dust phenomenon is one the problem that is developed due to human interference and unreasonable utilities from natural resources and their destruction. In this review, the dust phenomenon frequency was done using selected synoptic stations statistical in Alborz and Qazvin provinces during 2000 to 2014 that annual frequency was evaluated by extraction of dust codes from meteorological data statistically. In order to study of velocity and direction of region winds, wind rose and storm rose of Karaj and Qazvin stations were drew and prevalent wind direction was determined that it showed prevalent wind is northwest and southeast at Karaj and Qazvin stations respectively. Study of the effect of drought on dust phenomenon event was done using SPI, PNI, ZSI indicator for annual scale and was evaluated via SPSS software. The drought result show that 2013 was the driest year at Karaj station and the SPI, PNI and ZSI values were obtained -1.64, 58 and -1.39 respectively. Also 2008 was the driest year at Qazvin station and SPI, PNI and ZSI values were calculated -2.34, 50 and -1.99 respectively. With studying of annual dust frequency with regard to 06 and 07 codes detected that totally 169 days was reported as day with dust at Karaj station that 2012 and 2014 had the most event frequency. Furthermore, totally 115 days with dust accrued at Qazvin station that 2011 with 23 days had the most event frequency.
TAYYEBEH MESBAHZADEH; farshad soleimani sardou
Abstract
Due to incorrect policies in the water resources sector and excessive withdrawal of groundwater resources, water quality in most plains of the country has decreased. Therefore, the quality of water for drinking and agriculture is important in qualitative terms.With this aim in this study, the desertification ...
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Due to incorrect policies in the water resources sector and excessive withdrawal of groundwater resources, water quality in most plains of the country has decreased. Therefore, the quality of water for drinking and agriculture is important in qualitative terms.With this aim in this study, the desertification changes in Khash plain were studied using two criteria of groundwater and vegetation. Shooler and Wilcox diagrams were drawn up for AquaChem software for the years of 2001, 2008 and 2015. Also, spatial variations were made on Arctic plain surface using Arc GIS software and vegetation changes trend were also done using MOD13A2 sensor images and remote sensing techniques. The results showed that the number of wells that have an unpredictable TDS in the years 2008 and 2015 compared to 2001 have been increased by comparing the Schuler diagram. However, the level of lands with good drinking status decreased during the years 1387 and 1394 compared to 1380 and was increased by the level of acceptable drinking water. According to Wilcox's diagram, the result is that most wells are salty to very salty and their use is harmful to agriculture or requires measures. The results of the vegetation change trend also indicated that the trend is to reduce vegetation and the average level of the NDVI index decreases with the passage of time.
seyedeh khadijeh mahdavi; gholamreza houseynibamrooud; mouhamadhasan jouri; houseyn tavakouli
Abstract
Calligonum eriopodum is the only psammophyte shrub in Iran, which was reported from South Korassan. Searching of environmental limitation of the species was the goal of current research that has been done on dune lands around the east direction of the Qaen city in south Khorassan. First of all, the habitat ...
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Calligonum eriopodum is the only psammophyte shrub in Iran, which was reported from South Korassan. Searching of environmental limitation of the species was the goal of current research that has been done on dune lands around the east direction of the Qaen city in south Khorassan. First of all, the habitat boundary was cleared by field monitoring and GPS recording of points and the species distribution, and then was pointed at map scale 1:50,000. Sampling in inside and outside by using three 1000-meter transects were laid down on the land, and the soil and plant samples were selected using five by five meter plots. The soil samples were taken from the fifth plot in each transects. The water samples were obtained. The t test was done to compare the soil and water samples from two habitats. Results showed that the soil and vegetation conditions were statistically the same inside and outside the habitat. However, EC and TDS of water samples were significantly different two habitat (P-value<0.05). The EC rate of the water resources was less in the inside habitat position than the outside of the species habitat. The water table level (WTL) in the inside limatation in close to the surface was (less than five meters) while it was between twenty five to thirty two meters in the outside land. It can be stated in among environmental factors the WTL and the quality of water resources were the cause of establishing of the species in the dune lands.
Mahsa Mirdashtvan; Ali Najafinejad; Amir Sadoddin
Abstract
Trend and stationarity analyses of hydrological variables are useful tools for understanding climate change and may provide useful information about likely changes in the future. As non-stationary of time series can occur due to various reasons such as trend existence in data; therefor, in current study ...
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Trend and stationarity analyses of hydrological variables are useful tools for understanding climate change and may provide useful information about likely changes in the future. As non-stationary of time series can occur due to various reasons such as trend existence in data; therefor, in current study the non-parametric Mann-Kendall trend test was used to detect the trend of the data. A corrector approach, namely “TFPW” was utilized to modify the effects of serial dependence of the time series on the trend detection results. The stationarity of time series was tested by unit root and stationarity tests to evaluate the relationship between trend and stationarity of the time series. The results showed that the surface flows of all of the studied rivers have a decreasing trend; although the significant trends changed to insignificant ones after applying TFPW approach. The results of the stationarity tests showed non-stationary time series for all of the sites after removing the serial dependence of the series, which is a sign of the lack of trend existence in the time series; however, Latian station (Lar river) reveals non-stationarity after applying TFPW which may be originated from the existence of abrupt changes in the series. The findings of current study can help the planners and policy-makers and water resources managers to cope with climate change in the future.
Ali Yazdanpanahi; Khaled Ahmadaali; Salman Zare; Toraj Shabani Omran
Abstract
This study looked into the effect of different natural and urban waste compost biochar levels (0, 1, 3, and 5%), incorporated in sandy soil (total of 16 soil types), on the saturated hydraulic conductivity coefficient. For this purpose, the hydraulic conductivity of all 16 soil samples was determined ...
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This study looked into the effect of different natural and urban waste compost biochar levels (0, 1, 3, and 5%), incorporated in sandy soil (total of 16 soil types), on the saturated hydraulic conductivity coefficient. For this purpose, the hydraulic conductivity of all 16 soil samples was determined using the constant head method. Then, for all soils, parameters of Van-Genuchten-Mualem (VGM) model for soil moisture characteristic curve (SMC) were determined by RETC and ROSETTA software and inverse modeling based on easily accessible parameters such as soil particle size percentage (sand, silt, and clay), bulk density, field capacity, and permanent wilting point. These parameters were soil residual water content (θr), soil saturated water content (θs), α, m, n and Ks. Results indicated that increasing biochars results in an increase in the Ks for all soils. Soil No. 11 (soil + 5% natural biochar + 1% urban waste compost biochar) and then soil No. 13 with 64 and 61% reduction, respectively, had the highest reduction percentage in Ks. The maximum and minimum value of Ks were 707.9 and 254.8 cmd-1 which were related to soil No. 1 and 11, respectively. All doses of biochars had a significant effect on all VGM parameters (P<0.01) and increasing biochars resulted in an increase in θr, n, and m and decrease in θs and α.
