Ali Golkarian; Abbasali Mohammadian; Abolfazl Abdollahi
Abstract
The first condition for control erosion and improve of watershed with critical status, identify and prioritize areas and catchments with a critical situation. At the time of control activities implementation, this action causes, more considered higher priority areas and conservation programs focus on ...
Read More
The first condition for control erosion and improve of watershed with critical status, identify and prioritize areas and catchments with a critical situation. At the time of control activities implementation, this action causes, more considered higher priority areas and conservation programs focus on such areas. The purpose of this research is priorities for watershed management sub basins of Daryan watershed, using similarity to ideal option (TOPSIS) method. First, in this study, six criteria (population, average production, water resources, agricultural land surface, erosion and formation) to prioritize is selection, and then the weight of each criterion using entropy method was determined. Among the criteria studied population and erosion were the highest and lowest weight respectively. The results showed that among the 38 sub-basins studied, sub basin A10, A’11 and B’7_A’12_C’21 because of high-ranking criteria of population, water resources and agriculture have the highest priority and sub basin C6, C9 and C’7 due to the lower these criteria the lowest priority given to the watershed.
kazem Nosrati; sepide imeni; arash talari
Abstract
Sediment yield caused by soil erosion process as the most important land degradation index is considered a main challenge in sustainable development and threats the ecosystems. It is therefore very important to estimate the reliable sediment discharge at watersheds outlets. The large river drainage basins ...
Read More
Sediment yield caused by soil erosion process as the most important land degradation index is considered a main challenge in sustainable development and threats the ecosystems. It is therefore very important to estimate the reliable sediment discharge at watersheds outlets. The large river drainage basins and the lack of sediment gauges have led to apply regional analysis methods, to estimate suspended sediment load in the basins without gauges or the gauges with lack of data. The objective of this study was to estimate regional suspended sediment load using principal components regression in homogeneous regions of Sefidrood drainage basin with an area of 59273 km2as dependent variable and 18 physiographic and hydrologic factors in sediment load were recognized in each homogenous region based on principal components analysis (PCA). Finally, the relationship between suspended sediment load with different return periods and controlling factors were determined. The results showed that the stations located in the study area were clustered in two homogeneous groups. In the homogeneous region one, based on the PCA, 18 variables reduced into 5 factors accounting more than 87% of total variance and in the second homogenous region reduced into 3 factors accounting more than 92%. Using the principal component regression in the first homogeneous region, the first factor with the coefficient of determination of sediment discharge with 25- year return period, 0.67, and in the second homogeneous region, the first and second factors with coefficient of determination 0.32 were entered in model.
Abdolhosain Mohammadi; Reza Ghazavi; rohollah Mirzaei; Hamidreza Naseri
Abstract
Rainfall is one of the most important factors affecting vegetation cover. Fluctuation and year-to-year variation of rainfall always affect vegetation cover patterns. The main aim of this study was to investigate and modeling the effects of rainfall changes on the variation of the vegetation cover in ...
Read More
Rainfall is one of the most important factors affecting vegetation cover. Fluctuation and year-to-year variation of rainfall always affect vegetation cover patterns. The main aim of this study was to investigate and modeling the effects of rainfall changes on the variation of the vegetation cover in the Meyghan basin in Arak province using MODIS satellite images. NDVI, DVI, RVI and EVI indices were used to manifest vegetation covert variations linear and nonlinear relationship between vegetation cover changes and rainfall investigated simultaneously (May), with one and two month delay (April and March) ) during the statistical period of 2000-2017. The rainfall trend analysis was done using non-parametric Mann-Kendall test. According to the results, the minimum rainfall during the 18-year period was increased. Between vegetation indices, NDVI index showed the maximum and the average incremental trend. Between precipitation and vegetation, third-order non-linear relationship was stronger than linear, quadratic, power, logarithmic and exponential. The maximum correlation between DVI index and rainfall was obtained for synchronous times, while, the maximum correlation was observed between NDVI index and precipitation. The study with two month delay showed that the maximum correlation (0.52) was between the RVI index and precipitation. Vegetation modeling using simultaneous rainfall and delay of up to two months showed that the indices of DVI, RVI and EVI provided the best regression relationship at the same time, while the NDVI index had the best regression relationship with rainfall of two months ago.
Rasool Ghobadian; Zeynab Bahrami
Abstract
Increased exploitation of groundwater besides recent periods of drought caused a negative balance in Khezel aquifer located in Hamedan province, Iran. From 2000 to 2010, groundwater surface drop was estimated 5.8 meters. With regard to high potential of GMS in using GIS and careful stratification of ...
Read More
Increased exploitation of groundwater besides recent periods of drought caused a negative balance in Khezel aquifer located in Hamedan province, Iran. From 2000 to 2010, groundwater surface drop was estimated 5.8 meters. With regard to high potential of GMS in using GIS and careful stratification of the aquifer, GMS was used in present study to investigate and predict the groundwater table fluctuations in Khezel aquifer. Thus, Quantitative modeling was performed using MODFLOW model. The model was calibrated (using trial and error method) in two conditions: steady state (in september 2009) and transient state (from October 2009 to July 2010). Also, the quantitative model validated for August 2010. The impact of groundwater artificial recharge (within 31 injection wells for 5 months from October to March) was evaluated by calibrated model. Results showed maximum rise of water level was 19 cm in April. Next, in the same flow simulation stress periods, qualitative modeling was carried out by MT3DMS model. Optimum values of longitudinal dispersion and distribution coefficient were achieved by trial and error method and the qualitative model was calibrated. Statistical results of qualitative modeling are as follow: R2=0.98, slope of regresion line (y=1.0079x), mean error (ME=4.56 ppm) and RMSE=3.36%. Finally, dispersion of point source pollution (leaching pit) was investigated as a scenario. The result indicated that the radius of influence of leaching pits varies from 150 to 200 m in different areas. In continue, in the same flow simulation stress periods , qualitative modeling was carried out by MT3DMS model. Optimimum valuse of longitudinal dispersion and distribution coefficient were achived By trial and error method and the qualitative model was calibrated. Statistical results of qualitative modelling including: R2=0.98, slope of regresion line (y=1.0079x), mean erroe(ME=4.56 ppm) and RMSE=3.36%. Finally, dispersion of point source pollution (leaching pit) was investigated as a scenario. The result indicated that, the radius impact of leaching pit varying from 150 to 200 m.
parisa niknam; Reza Erfanzadeh
Abstract
In this study, the effect of cushion plants on spatial distribution of soil seed bank was studied in mountainous and hilly rangelands in Vaz watershed, Mazandaran province. Therefore, we selected randomly 20 Onobrychis cornuta individuals and sampled from soil at four positions around each individual ...
Read More
In this study, the effect of cushion plants on spatial distribution of soil seed bank was studied in mountainous and hilly rangelands in Vaz watershed, Mazandaran province. Therefore, we selected randomly 20 Onobrychis cornuta individuals and sampled from soil at four positions around each individual (upslope, downslope, center and, outside as control). Soil samples spread out under natural conditions in greenhouse to germinate the seeds. Germinated seeds were identified then, the seed density per square meter and species richness were calculated and both of them were compared between the four sampling positions. Two and one-way ANOVA, T-test and Duncan test were used to compare the effect of location, depth and their interaction on soil seed bank characteristics. The results showed that the effect of the location and depth of the density and species richness at level of 0.01% were significant. The results of Duncan test showed that seed density in the upslope and center positions (average 5473 and 4099.5 seed/m2, respectively) was significantly higher than seed density in the downslope and outside positions (average 2685.5 and 2413.8 seed/m2, respectively). Similarly, species richness in the upslope and center positions (the average 9.7 and 9.5, respectively) was significantly higher than species richness in the downslope and outside positions (average 7 and 6.4, respectively). Density and species richness of soil seed bank at depth of 0-5cm was significantly greater than the depth of 5-10cm. This study clarified the positive significant effect of canopy of cushion plants on seed density and richness.
javad Motamedi(torkan); Hossein Arzani; morteza mofidi; esmaeil sheidaye karkaj; sahar babayi
Abstract
The role of shepherds in maintaining, managing and distributing livestock in rangelands is very important. Flock guidance plays a major role in the distribution of grazing and livestock performance in rangelands. Therefore, it is necessary to evaluate the existing spatial system and it is clear to what ...
Read More
The role of shepherds in maintaining, managing and distributing livestock in rangelands is very important. Flock guidance plays a major role in the distribution of grazing and livestock performance in rangelands. Therefore, it is necessary to evaluate the existing spatial system and it is clear to what extent livestock are given in appropriate places according to ecological criteria and indices. The present study was conducted to evaluate the role of shepherds in herding and distribution of livestock (sheep) and its adaptation to rangeland suitability map. Record of movement of livestock in different months of the grazing season by GPS and its adaptation to rangeland suitability map which is led by shepherds in areas where the limitations of forage production and sometimes, the sensitivity of soil to erosion, have little value for why. Therefore, the hypothesis of the study that shepherd does not play an effective role in the distribution of livestock on the basis of rangeland merit is confirmed and given that shepherds have given the animals in places where they have little merit for why, it is concluded that the spatial system in the rangelands of the region is not efficient. Therefore, the use of new technologies such as GPS and electrical fences along with native knowledge in order to properly control the herd and reduce the burden of livestock grazing in the areas that are not based on ecological criteria and indicators, do not have the necessary merit, is suggested.
Ali Norouzi; iman haghiyan; Esmaeil Sheidai Karkaj
Abstract
Rangelands as a source of meat, forage, water and soil play a significant role in the country's economy, but the increase in the number of livestock and livestock in the rangelands has eliminated the balance between production and harvest. In this research, the effect of rangeland projects on various ...
Read More
Rangelands as a source of meat, forage, water and soil play a significant role in the country's economy, but the increase in the number of livestock and livestock in the rangelands has eliminated the balance between production and harvest. In this research, the effect of rangeland projects on various indices such as plant diversity, condition, rangeland trend, production and canopy cover percentage in five rangeland (Tajrud, Sangolabad, Ali Abad, Garmab and Dochahi) located in Torbat Heydarieh county has been investigated. For this purpose, after measuring the mentioned indices in the rangelands (treatment) and their adjacent sites as a control, statistical analysis were performed using t-test. The results of the comparison of the mean vegetation percentage indicate that the canopy cover percentage of the planted area with the rate of 51/64% is higher than the ungraded area with a rate of 47.5% with a significant canopy at 5%. Also, despite the high number of production in the area with a plot (73.08 kg / ha), compared to the area without design (67/99), this difference is not significant. The average score of the score for the area inside the project (27.4) and outside the plan (23.4) are not statistically significant with each other. The implementation of rangelands in three regions from all five regions has been proven to negatively affect rangeland tendency. Also, the implementation of the rangeland scheme has significantly increased the Shannon-Wiener heterogeneity indices and Simpson's uniformity in the design, rangeland has not changed significantly in the Margalaf richness index.
Masud Nasri; Reza Modares
Abstract
Although a number of studies have been carried out around meteorological drought in Isfahan province, there is no specific study about hydrologic drought. In this study, low flows trend was analysed for the first time as the most important indicator of hydrologic drought in Isfahan province watersheds. ...
Read More
Although a number of studies have been carried out around meteorological drought in Isfahan province, there is no specific study about hydrologic drought. In this study, low flows trend was analysed for the first time as the most important indicator of hydrologic drought in Isfahan province watersheds. Mean daily stream flow as a hydrologic indicator and 1-, 7-, 15-, 30- and 90-day low flows were estimated as hydrologic drought indicators for 22 gauging stations with at least 20 years of data record. Results of trend analysis using Mann-Kendall and Spearman correlation indicated that mean daily stream flow and low flows have negative trend at many gauging stations. Apart from GhalehShahrokh station, low flow indices in Zayandehrud dam basin have negative trend so that Eskandari station shows the highest degree of negative trend. Daily stream flow and low flows reduction especially in recent years is kind of warning for water resources management in Zayandehrud basin.
Hamidreza Koohbanani; Mohammadreza Yazdani
Abstract
Approximating the evapotranspiration is one of the most difficult parts of the hydrologic cycle. However it plays a very important role in the water balance equation. In the present study, the SEBAL model has been revalidated as an approved and successful approach for calculating the evapotranspiration. ...
Read More
Approximating the evapotranspiration is one of the most difficult parts of the hydrologic cycle. However it plays a very important role in the water balance equation. In the present study, the SEBAL model has been revalidated as an approved and successful approach for calculating the evapotranspiration. In SEBAL model, the evapotranspiration is the unknown value in the equation of surface energy balance for the land surface. Considering the differences in the calibration of LDCM compared to the previous generations of the Landsat satellite, the SEBAL model was reexamined in some especial parts. In order to test of the usefulness of SEBAL model over LDCM, the measured values was compared with the values obtained via Penman-Monteith method in 20 different days. ET estimated by SEBAL compared with PM ET was found to correlate significantly as R2 (0.7) with the correlation coefficient of 0.83. Hence the results of this analysis outline that actual evapotranspiration data can be calculated and mapped in large areas and with high reliability without the need for meteorological information periodically and regularly.
Aliakbar Nazari Samani; Behnaz Zarrin; Shahram Khalighi sigaroudi
Abstract
Rainfall erosivity (RE) energy is an important factor on the soil detachment and transition of them implying an important role on the regional potential region erosion. . In this study SPI index was used in order to determine the climate condition and its consequent effects on RE in Fashand watershed, ...
Read More
Rainfall erosivity (RE) energy is an important factor on the soil detachment and transition of them implying an important role on the regional potential region erosion. . In this study SPI index was used in order to determine the climate condition and its consequent effects on RE in Fashand watershed, Elburz province. At first the drought, wet and normal periods were determined for four rain gage station and then, both EI30 and modified Fournier index (MFI) were calculated at each gauge station. The regression analysis was used to investigate the relationship between EI30, MFI and 24-hour rainfall as well as annual rainfall of data-logging rainfall stations. After that through applying the regression equation the EI30 was extrapolated for eleven typical rain gauges over the different climate periods. The best correlation was obtained between EI30 and annual rainfall (R2 = 0.71). The spatial zonation RE maps were extracted through Geostatistical analysis for drought, wet and normal condition . According to the findings the effects of climate variability on the amount of RE are significant. Maximum and minimum RE are related to the wet and dry period respectively. However the RE on the summer season of dry condition is more than the wet condition and such condition together with low vegetation cover related to the drought condition lead to complicated situation. Despite the popular thought that the low RE can be addressed into the drought condition the rainfall pattern affect the erosivity potential and not the amount of precipitation.
Mohammad Reza Yazdani; Ali Asghar zolfaghari
Abstract
Watershed outflow has influenced by different factors such as climatic, human and physical aspects and this Variability of effective factors can cause complex conditions, difficulty of flow forecasting and it mainly originates by different local and temporal scales of these factors. Also, some remote ...
Read More
Watershed outflow has influenced by different factors such as climatic, human and physical aspects and this Variability of effective factors can cause complex conditions, difficulty of flow forecasting and it mainly originates by different local and temporal scales of these factors. Also, some remote meteorological signals can cause changes in meteorological conditions in different regions. Hablehrud river flow has a vital role in regional development, especially for agricultural section. Thus research of river flow forecasting should be done for water resources management especially when there are drought and climate change conditions in order to facilitate sustainable development. In this study four nonlinear models of artificial neural networks including Generalized Feed Foreward Networks (JFNNs), Jordan/Elman Networks(JENs), Time Lag Recurrent Networks(TLRNs) and Radius Basis Function Networks(RBF) was used to modeling Hablehrud river flow(Bonkuh station) during 1982 to 2011. Input variables after sensitivity analysis were used in 4 models and 4 scenarios. Ten teleconnection indexes were used as input of the model to evaluate their roles in model capability. Results indicated that in the test stage Jordan/Elman Networks represented lower error compared with selected models (RMSE for 4 scenarios are5.57, 4.9, 5.35 and 4.62 respectively). In general error showed decreasing trend from first scenario to the last. Error was decreased of 15 to 31 percent by using teleconnection patterns as inputs (GFFN=%26, JEN=%15.8, TLRN=%25.5 and RBF=%31.7). Totally using teleconnection indexes as inputs in the modeling stage can diminish error of flow forecasting, although selected models indicated different results due to its variable topologies.
mojdeh mohammadi; Hossein Malekinezhad; Mohammad Taghi Dastorani
Abstract
Main problems in flood frequency analysis are limited number of gauging stations and recorded data, together with the inaccurate at-site estimations in the study area. These problems have caused increasing application of regional methods. Regional analysis seems to be a useful method for estimating peak ...
Read More
Main problems in flood frequency analysis are limited number of gauging stations and recorded data, together with the inaccurate at-site estimations in the study area. These problems have caused increasing application of regional methods. Regional analysis seems to be a useful method for estimating peak flow at an area of no data or low-recorded length. Regional flood frequency analysis relies on physical and climatic characteristic of basins and applies statistical method to study flow records. The methods of regional analysis are numerous that the selection of each one of them in any study area depends on data length, climatic factors, data type and expected return periods. In this study, four techniques of regional analysis were used to evaluate the priority and importance to estimate the peak flow for different return periods. The Hybrid, Multiple regression, L-moments and Canonical Correlation Analysis are the four approaches applied for some watersheds of Isfahan–Sirjan and Yazd-Ardakan Basins. A number of 16 stations were selected and their data were analyzed to find out peak flow. The results of this analysis were compared to the Hybrid and Multiple regression approaches using RRMSE and MAE statistics. The results showed better performance of the CCA method rather than other methods in all return periods. After CCA, Multiple regression methods were selected to estimate the peak flow (Model 2, 3). Therefore, CCA method can be adopted as regional flood frequency method for the study area.
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 ...
Read More
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.
Reza Namjooyan; Jamshid Ghorbani; Ghodrat alah heydari; Ghorban Vahab Zade
Abstract
Activities related to the extraction of minerals are one of the factors causing a disturbance in rangelands. Vegetation succession in mining areas depends on the soil seed bank. For this purpose, the soil seed bank was studied in two important coal extraction sites in Mazandaran province to identify ...
Read More
Activities related to the extraction of minerals are one of the factors causing a disturbance in rangelands. Vegetation succession in mining areas depends on the soil seed bank. For this purpose, the soil seed bank was studied in two important coal extraction sites in Mazandaran province to identify and compare seed amount between coal wastes and nearby rangeland as control. Soil and coal wastes samples were taken from 140 plots of 1 m2 in Kiasar coal mine and 115 plots in Karmozd coal mine before the growth season. Samples were kept in a glasshouse for eight months germinated seeds were counted. Results of this study showed that the germination of 28 species in Kiasar and 23 species in Karmozd. 10 and 6 species only presented in Karmozd and Kiasar coal waste, respectively. Annuals dominated the coal waste seed bank in Kiasar while perennials were common in Karmazd coal waste seed bank. In Kiasar, coal waste seed bank had less diversity and richness than that in seed bank of rangelands, but no significant differences were observed between seed bank of coal waste and seed bank of rangeland in Karmozd. Due to the harsh conditions of seed germination and seedling establishment and also low seed density in the seed bank, natural regeneration in coal wastes of these two sites will be a slow process and it needs amendment treatments and the introduction of target plants seeds.
fatemeh naghizadeh; mohammad jafari; hosein azarnivand; Mohammad Ali Zare Chahouki
Abstract
In this study, the role of soil properties in making difference between plant communitieswas examined. First, four plant types were identified, including Pteropyrumaucheri-Salsolarigida، Astragalus gossypinus - Acanthophyllum herateens، Amygdalus scoparia – Achilla millefolium and Ephedra intermedia ...
Read More
In this study, the role of soil properties in making difference between plant communitieswas examined. First, four plant types were identified, including Pteropyrumaucheri-Salsolarigida، Astragalus gossypinus - Acanthophyllum herateens، Amygdalus scoparia – Achilla millefolium and Ephedra intermedia – Erigon capestra, through randomized systematic sampling and field survey in representative area of each type. In each plant type, three 500-meter transects were selected and in each transect, ten plots were placed along each transect. Characteristics of vegetation such as type and percentage of cover, gravel percentage, litter percentage and bare soil percentage were determined within each plot. In addition, in order to study the soil properties, at the beginning and at the end of each transect, a profile was dug and soil samples were taken from the depths of 0-20, 20-80 cm. Soil physical and chemical properties (texture, pH, electrical conductivity, organic matter percentage, gypsum percentage, lime percentage, salts such as sodium, potassium, calcium and magnesium, sodium absorption ratio, sodium exchange percentage) were determined in soil laboratory. Then, the role of soil properties in making difference between plant communitieswas determined by using ANOVA statistical analysis, and the key factors making this difference were introduced as sand percentage, organic matter percentage, and electrical conductivity.
Ali Akbar Nazari Samani; alireza oliaye; sadat feiznia
Abstract
Assessment frequency of springs has become an important issue for land use planning, especially water resource identification and environmental protection.The purpose of this study is to produce a spring occurrence potential map in Bojnourd Basin, based on a logistic regression method using Geographic ...
Read More
Assessment frequency of springs has become an important issue for land use planning, especially water resource identification and environmental protection.The purpose of this study is to produce a spring occurrence potential map in Bojnourd Basin, based on a logistic regression method using Geographic Information System (GIS) and remote sensing (RS). The locations of the springs (359 springs) were determined in the study area. In this study, 14 effective factors including spring were used in the analysis: lineament density, distance to lineament, distance to drainage, drainage density, normalized difference vegetation index (NDVI), profile curvature, tangential curvature, surface rate, vector dispersion, precipitation, elevation, geology, aspect and slope. Binary logistic regression coefficients of the variables by selecting 300 spring randomly. 59 another spring were used for validation that 80.6% of the springs were correctly predicted. The accuracy of the model was measured using ROC curves which showed that accuracy is 86.6 percent which indicates that the model shows high accuracy in the analysis of spring occurrence potential in the study area. The results showed that the distance of lineaments, distance of drainage, drainage density, vegetation index, profile curvature, tangential curvature, vector dispersion, precipitation and slope have the greatest impact on the occurrence of springs. Finally, spring occurrence potential map was divided into four probably classes of very low, low, medium and high. According to the survey results, this method can be used to identify sources of groundwater in karstic zones and has important role in better management of the karstic Basins.
hossein norouzi; ataallah nadiri
Abstract
123
Groundwater system studies to understanding its behavior, requires the exploratory drilling wells, pumping test and geophysical experiments, which can carried out with most cost. For this reason, simulation of groundwater flows by mathematical and computer models, which is an indirect method to ...
Read More
123
Groundwater system studies to understanding its behavior, requires the exploratory drilling wells, pumping test and geophysical experiments, which can carried out with most cost. For this reason, simulation of groundwater flows by mathematical and computer models, which is an indirect method to groundwater studies, is being spent a few costs. In this research, the efficiency of artificial neural network, fuzzy logic and random forest models has been investigated in groundwater level estimation of Boukan plain. Parameters of precipitation, temperature, flow rate and water level within time period of the previous month were used as input and the water table in each period were selected as output through monthly scale (2006-2017). To evaluating the performance of models, Correlation coefficient, root mean square error and coefficient of mean absolute error were used. The results showed that the Fuzzy Logic and Random Forest models are able to estimate water levels with acceptable accuracy. In terms of accuracy, fuzzy logic model with the highest correlation coefficient (0.96), lowest root mean square error (0.068 m0) and mean absolute error (0.056 m) was recognized as a best the model in the groundwater level prediction.
Aliakbar Nazari Samani; mahmoud samadi; arash malekian
Abstract
For developing of water resources a lot of different factors (such as: geological structure, faults, joints and geomorphological metrics) are important. This research tried to assess the effects of geomorphology on karstic water resources in central Elburz region. Geomorphometrics indices were prepared ...
Read More
For developing of water resources a lot of different factors (such as: geological structure, faults, joints and geomorphological metrics) are important. This research tried to assess the effects of geomorphology on karstic water resources in central Elburz region. Geomorphometrics indices were prepared in the form of separate layer in GIS and RS and were overlaid on the springs distribution map. To assess the relationship between springs frequency, discharge and geomorphology statistical analysis such as correlation and factor analysis were done. Results indicate a close relation between spring occurrence and hillslope curvature and TPI. Also the Pearson correlation coefficient of elevation and lineament density and drainage density was significant (P<0.01). According to results the discharge of springs are directly related to drainage density and indirectly related to elevation and lineament density. Moreover the fetor analysis on 17 variables revealed that the first six components had Eigen value of more than 1 and 73.5% of total variance was explained by them. Result indicated that for future developing such a geomorphology characteristics can give suitable information of water resources.
sedigheh mohamadi
Abstract
This research was done to investigate the effects of change in land use on chemical soil properties in Jamalabad region of Baft county of Kerman province. The experiment was conducted in six sites with the same ecological condition as non grazed site (NG) for 10 years, a moderately grazed site ...
Read More
This research was done to investigate the effects of change in land use on chemical soil properties in Jamalabad region of Baft county of Kerman province. The experiment was conducted in six sites with the same ecological condition as non grazed site (NG) for 10 years, a moderately grazed site (MG) and a heavily grazed site (HG), a dry farming site of barley and wheat (D), a long time fallow site for 5 years (F) and a plowed Glycyrrhiza glabra site (Gl T). Soil samples were collected from two soil horizons (0-15 and 15-30 centimeters) based on a randomized complete blocked design with six replications from each horizon in 2013. Samples were sent to laboratory for soil chemical properties as organic carbon, total nitrogen, available phosphorus, available potassium, PH and electrical conductivity. The results indicated that Land use change significantly decreased organic carbon, potassium content, available phosphorous and nitrogen content as 58.2, 21, 23.5 and 71 percent in dry farming site and 58, 17.3, 19 and 60 percent in plowed Glycyrrhiza glabra site compared to non grazed site. A decreasing trend of organic carbon was seen in moderately and heavily grazed sites in comparison to non grazed site as 42 and 56 percent, respectively. Available potassium of moderately and non grazed sites were maximum. Total nitrogen of soil in moderately and heavily grazed sites was decreased in comparison to non grazed site as 0.035 and 0.04 percent. PH of soil was significantly changed only between non grazed and plowed Glycyrrhiza glabra site (Gl T). Electrical conductivity of soil was increased in dry farming site (165 percent) and heavily grazed site (140 percent) in comparison to non grazed site. According to negative effects of land use change on soil quality and remaining this harmful effect after release of dry farming lands, our recommendation to natural resources offices are programs preventing rangeland occupying, minimizing giving off rangelands, rehabilitation of released dry farming by pioneer plants and improvement of soil qualities in root collection designs of Glycyrrhiza glabra.
roya vazirian; hamid reza asgari
Abstract
Abstract: Soil particles are one of the most effective characteristics related to erodibility and main hydrological and physical aspects of soil. This is important to understand soil characteristics which control soil stability in the case of conservation of soil structure. Also, recognizing critical ...
Read More
Abstract: Soil particles are one of the most effective characteristics related to erodibility and main hydrological and physical aspects of soil. This is important to understand soil characteristics which control soil stability in the case of conservation of soil structure. Also, recognizing critical soil properties such as organic matters in the regions, where soil erosion is resulted from natural patterns of aggregates will be fundamental key in conservation strategies. In this paper, organic matter measurement, discovery of particles stability and interactions between these two factors have been aimed. Sampling was done in three different densities (<200, 200-400 and >200 stand per hectare) and 30 replications. The results revealed that Atriplex spp. Increased soil organic matter and also soil stability. Different planting distances were not effective in level of 5%. Therefore; improvement of soil particles stability and controlling soil erosion in the study area depend on soil management and implication of soil conservation projects.
Hamidreza Naseri; Nateq Lashkari sanami; Seyed Ali Sadeghi Sangdehi
Abstract
In order to provide animal’s nutritional requirements and production of animal protein, it is necessary to adjust the balanced diet and the correct nutrition plan., which is based on proper understanding of food and this is possible through the analysis of nutrients. This research aimed to study ...
Read More
In order to provide animal’s nutritional requirements and production of animal protein, it is necessary to adjust the balanced diet and the correct nutrition plan., which is based on proper understanding of food and this is possible through the analysis of nutrients. This research aimed to study and compare of forage quality in seven species that are grazing by camel including: Nitraria schoberi , Smirnovia iranica , Seidlitzia rosmarinous , Stipagrostis plumosa, Astragalus squarrosus, Alhaji persarum and Zygophyllum eichwaldii conducted in two stages of vegetative growth at Maranjab desert rangelands. For this purpose, the indices of dry matter (DM), Crude Protein (CP), Dry Matter Digestibility (DMD), Acid Detergent Fiber (ADF), Metabolic Energy (ME), Nitrogen (N), Phosphorus (P), Potassium (K) and Sodium (Na) were subjected to chemical analysis. The results showed that the forage quality indices between the species and phonological stages were significantly different (P<0.01). In all species, as the growth stages and plant maturity progressed, the amount of crude protein, metabolic energy and phosphorus were decreased and the amount of dry matter and ADF were increased. While N. shoberi had the highest amount of crude protein (26.51) in vegetative growth stage, S. rosmarinous showed the lowest protein (3.91) at seeding stage. In addition to, with regard to both phonological stages, while the highest dry matter digestibility, metabolic energy, potassium and sodium were found in S. rosmarinous species, the highest amount of crude protein, nitrogen and phosphorus was observed in S. iranica species.
Mehrnaz Neyestani; Fereydoon Sarmadian; Azam Jafari; Ali Keshavarzi
Abstract
In digital soil mapping, soil characteristic and classes could be extracted truly by numerical and quantitative modelling. Hence, derived rules could be fitted to similar regions for achieving ruled relations on areas without soil information which is called as extrapolation. In the present study, achieving ...
Read More
In digital soil mapping, soil characteristic and classes could be extracted truly by numerical and quantitative modelling. Hence, derived rules could be fitted to similar regions for achieving ruled relations on areas without soil information which is called as extrapolation. In the present study, achieving digital soil class map of an area without adequate soil information by Random forest was tested by extrapolation at great group level. The results show overall accuracy 88% and kappa 0.77 of donor area which is able to fit over its similar region. Results of extrapolation show overall accuracy 81% and kappa 0.61 of recipient area which could show logical concordance to produce soil class map of recipient area without applying related soil samples of this area in short time and low cost. Since, extrapolation could be as an efficient way to predict soil classes of unknown areas.
khadije naghizadeh; mohammad jafari; hosein azarnivand; mohamad ali zare chahiiki; Hamidreza Abasi
Abstract
The effect of environmental factors on vegetation diversity in Eshtehard rangeland was studied in present study. Sampling was done using Minimal Area method. To measure the plant properties in each type, regarding the extent of each type, three 500 meter transects with 50 meter intervals between transects ...
Read More
The effect of environmental factors on vegetation diversity in Eshtehard rangeland was studied in present study. Sampling was done using Minimal Area method. To measure the plant properties in each type, regarding the extent of each type, three 500 meter transects with 50 meter intervals between transects (due to the scarce vegetation cover) were established. In each plot, the number and types of existing species and their percentages were determined. Also, profiles were dug at the beginning and end of each transect and soil specimens were sampled at 0- 20 cm depth. Among soil properties, the percentage of clay, silt, sand, organic matter, lime, acidity, electrical conductivity, calcium, magnesium, sodium and potassium were measured. After collecting data, Shanon-Winer species diversity and Simpson indices were determined using Ecological methodology Software. Finally, the most important factors effecting the species diversity variation were specified using Principle Component Analysis. The results showed that among the studied factors, elevation, slope, soil depth and lime are the most effective ones.
