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Open Access Article
1 - Temporal and spatial variability of groundwater salinity in Urmia plain
Reza Sokouti OskoeeThe intensify process of lowering Urmia lake level has led to reduce water quality, making it brackish and unusable in wells of Lake Marginal Lands. The present study investigated changes in groundwater salinity in Urmia plain using geostatistical models, and MoreThe intensify process of lowering Urmia lake level has led to reduce water quality, making it brackish and unusable in wells of Lake Marginal Lands. The present study investigated changes in groundwater salinity in Urmia plain using geostatistical models, and compares the results of the mapping in three time periods. To assess salinity of the groundwater, data from 57 wells in the period of 1380, 1384 and 1387 were analyzed, using Kriging in GIS, GS+ and ARCVIEW8 softwares. The results indicated that application of Kriging, experimental semi-variogram with spherical model provided better predictions with correlation coefficient of 0.99. According to the obtained groundwater salinity maps, land area with more than 2 dS/m groundwater salinity in 1380 was equal to 1924 hectares that has increased to 8331 hectares in 1387. During these years, in the study area the groundwater salinity with less than 1 dS/m was decreased about 14675 hectares. The observed maximum salinity value in 1380 has increased from 1.91 to 5.8 dS/m in 1387. Manuscript profile -
Open Access Article
2 - Efficiency of some geostatistical estimators for interpolation and mapping some soil quality properties
Seyedeh Mahbube Mousavifard Hamid Reza Momtaz Habib KhodaverdilooFor design and implementation of soil conservation programs, accurate and optimized mapping of soil properties is required. The type of interpolation method is one of the most important issue involved in mapping soil properties. Six ordinary methods of spatial interpola MoreFor design and implementation of soil conservation programs, accurate and optimized mapping of soil properties is required. The type of interpolation method is one of the most important issue involved in mapping soil properties. Six ordinary methods of spatial interpolation were compared to determine their suitability for estimating some quality properties of topsoil including clay content, electrical conductivity, equivalent calcium carbonate and organic carbon in the Naqade region farmlands located in west Azerbaijan. The area of study region was about 8300 ha. For this purpose, 282 topsoil samples were collected randomly and tested for laboratory analysis. Deterministic methods (radial basis function and global polynomial interpolation) as well as geostatistical estimators (ordinary Kriging) were utilized to map related soil properties. The highest and lowest CV was obtained for EC and clay content variables, respectively. For clay and electrical conductivity, the exponential model, for equivalent calcium carbonate the Gaussian model, and for organic carbon the spherical were the best fitting models to calculate the experimental variogram. According to the results, the ordinary Kriging approach characterized with the minimum error indicator of bias-variance trade-off (BVTO) for evaluating clay, electrical conductivity, equivalent calcium carbonate and organic carbon. The thin plat spline model of radial basis function showed the maximum error in assessment of studied attributes. Eventually, the interpolation maps were generated regard to the most appropriate interpolators. Manuscript profile -
Open Access Article
3 - Comparing the applicability of some geostatistical methods to predict variability of some soil physical properties
Jalal Mahmoudi fatemeh Zareian Mohamad Reza Javadi Nazila khorsandiReasonable estimation of soil physical properties is very important for optimal management of soil and water resources. Estimation of soil physical properties is usually time consuming and expensive. Geostatistical methods can be used as suitable tools to esti MoreReasonable estimation of soil physical properties is very important for optimal management of soil and water resources. Estimation of soil physical properties is usually time consuming and expensive. Geostatistical methods can be used as suitable tools to estimate such properties. In order to analyze spatial variability of soil properties in Dareh Viseh rangelands, a number of 78 soil samples from 0-30cm soil depth were taken and transferred to laboratory. Some soil properties including clay, silt, sand and bulk density were measured in laboratory. After normalizing the data, the semivariograms were obtained and evaluated. The Kriging, inverse distant weighting and radial basis function methods were then evaluated for the obtained data. To compare these methods, the cross validation method was used by statistical parameters of Mean Absolute Error (MAE) and Mean Bias Error (MBE). The results showed that the Kriging method can provide more reseanable predictions for silt, sand and bulk density, while the radial basis function provides better estimate to predict clay content in the study area. Manuscript profile -
Open Access Article
4 - Study of Local and Temporal Changes of Groundwater Quality Standards of Hamedan-Bahar Plain Using (GIS) over a 10 Year Period
Sahar Eghbalian omid BahmaniBackground and objective: Groundwater is the valuable resources for drinking, agriculture and industry uses in the most regions of Iran. Groundwater qualitative changes can be created by human activity and industrial development. Study of these resources is necessary in MoreBackground and objective: Groundwater is the valuable resources for drinking, agriculture and industry uses in the most regions of Iran. Groundwater qualitative changes can be created by human activity and industrial development. Study of these resources is necessary in order to maintaining and improving their quality. The objective of this study is zoning and regional the specification parameters point of the case study. Finally determined the best method for zoning the each of the variables and permitted and infect areas in agricultural uses. In addition behavior variables were investigated in the 10 year period of time. Method: Qualitative data of Hameda-Bahar plain in Ten-year period were used in this study. Variables such as EC, TDS, SAR, HCO3, PH, Cl & Na evaluated by Geostatical methods include of Ordinary Kriging(OK),(by Circular, Gaussian, Exponential and spherical Semivariogram Modeling) and the specific methods include inverse distance weights (IDW), radial basis functions (RBF), global polynomial interpolator (GPI) and local polynomial interpolator (LPI), were zoning with ARCGIS9.3. Findings: Results indicated that the best method to zoning the qualitative parameters were IDW (EC), RBF (TDS), OK exponential semivariogram (HCO3), IDW (PH), RBF (Cl), OK exponential semivariogram (Na) and RBF (SAR) in Hamedan-Bahar plain. According to the best method the zoning of parameters was done for 2005, 2009 and 2014 years. Discussion and Conclusion: Results showed that Na had the maximum changes in ground water during the study period. The area percent for this parameter increased 3.21% from 2005 to 2014. Manuscript profile -
Open Access Article
5 - Estimating the Spatial Distribution of Above-ground Carbon of Zagros Forests using Regression Kriging, Geographically Weighted Regression Kriging and Landsat 8 imagery
somayeh izadi Hormoz SohrabiBackground and Objective: Estimating aboveground carbon (AGC) of forest is a fundamental task for sustainable management of forest ecosystems; therefore, there is a critical need for appropriate approaches for quantifying of AGC. The most commonly used approaches for es MoreBackground and Objective: Estimating aboveground carbon (AGC) of forest is a fundamental task for sustainable management of forest ecosystems; therefore, there is a critical need for appropriate approaches for quantifying of AGC. The most commonly used approaches for estimating include global regression models that estimate the target variable over a wide range using cost-effective auxiliary data. Traditional regression models with fixed regression coefficients at all locations do not consider heterogeneity and spatial structure in modeling. The objective of this study is estimating the AGC using Regression Kriging, Geographically Weighted Regression Kriging and Landsat 8 data and compare methods. Material and Methodology: The study was carried out in part of Zagros Forest, in Kohgiluyeh and Boyer-Ahmad Province. Totally, 184 plots (30×30 meters) surveyed and AGC were calculated by allometric equations. 32 variables were extracted from Landsat 8 as auxiliary data in the modeling process. The assessment of accuracies of methods was evaluated by K-fold cross validation via criteria such as coefficient of variation (R2), root mean square error (RMSE). Findings: The results showed that Geographically Weighted Regression Kriging (R 2 = 0.66, RMSE= 21) had a better performance compared to Regression Kriging. Discussion and Conclusion: Hybrid methods with heterogeneity and spatial correlation can be a good alternative to early regression methods for estimating aboveground carbon (AGC). Manuscript profile -
Open Access Article
6 - Evaluation of the concentration and distribution pattern of lead, zinc, chromium and cadmium in surface sediments of Karun River using geostatistics in GIS environment
MIR MEHRDAD MIRSANJARI fariba hedayatzadeh Hamid Reza pourkhabbazBackground and Objective: In aquatic ecosystems heavy metals are very important due to their toxicity and endurance and having a high bio-accumulation in the environment. The aim of this research, Evaluation of the concentration and distribution pattern of heavy metals MoreBackground and Objective: In aquatic ecosystems heavy metals are very important due to their toxicity and endurance and having a high bio-accumulation in the environment. The aim of this research, Evaluation of the concentration and distribution pattern of heavy metals (lead, zinc, chromium and cadmium) in surface sediments of the Karun River.Material and Methodology: To determine the concentration and distribution of heavy metals (lead, zinc, chromium and cadmium) in sediments of the Karun River in summer and winter of 2015, six stations were selected and from each station 3 samples of sediments were randomly collected. After transferring samples to the laboratory, drying and digestion of samples, the measurement of heavy metals was performed using a Flame atomic absorption spectrometry. An inverse weight-distance method was used to interpolate the distribution of heavy metals.Findings: According to the results, zinc had the highest concentration and cadmium had the lowest concentration among the studied metals in the surface sediments of the Karun River. The mean concentrations of lead, zinc, chromium and cadmium in summer were 26.28, 72.36, 53.48 and 3.85 μg/g dry weight and in winter were 13.47, 59.59, 30.26 And 0.42 μg/g dry weight, respectively.Discussion and Conclusion: Comparison of the measured heavy metals concentration by the American and Canadian national guidelines indicated that levels of Cr in the summer and Cd in surface sediments were higher than the Threshold effect level (Canadian Guideline) and Lowest Effect Level (NOAA Guideline). Whereas Concentrations of other metals were lower than mentioned limits. The findings of this study provide useful information on the distribution of heavy metals concentration in the Karun River sediments which can help monitoring and assessment of sediments in the region. Manuscript profile -
Open Access Article
7 - Comparison of Fractal Geometry and Kriging Methods to Estimate the Effect of Length Scale on Dispersivity of Reactive Elements in Soil
Yasser Hosseini Behrouz Mehdi nejadianiBackground and Objectives: Hydrodynamic dispersion rate of solutes in soil is considered as the major parameter for pollution and solutes transport in soil, which is related to pollutant transport distance. As fractal geometry theory and geostatistical theory are capabl MoreBackground and Objectives: Hydrodynamic dispersion rate of solutes in soil is considered as the major parameter for pollution and solutes transport in soil, which is related to pollutant transport distance. As fractal geometry theory and geostatistical theory are capable of explaining and predicting the distance-related phenomena, this research used fractal geometry and geostatistics method for determining dispersivity. Methods: Solutes transport experiment was carried out at 16 points of soil vertical column with a diameter of 10 centimeters and a length of 1 meter and BTCs were extracted at the depth of 6, 12, 18, 24, 30, 36, 42, 54, 48, 60, 66, 72, 78, 90, 84, 96 centimeters from the model bottom. CDE equation was then fitted with the BTCs with respect to the fractal assumptions on dispersivity coefficients. Findings: With respect to phosphorus absorption experiments in soil, phosphorus adsorption isotherm had the best fitting at 4, 12, 25, 50, 70 mg/l of phosphorus concentrations. The results showed that both methods are capable of predicting changes and increase of dispersivity coefficient in soil column after performing a mean-comparison test. However, fractal geometry method estimated values at a higher accuracy. Discussion and Conclusion: Result showed that, dispersivity along the sample followed the exponential relation. The regression coefficients of the fractal and geostatistical models in predicting dispersivity values were 0.97 and 0.84, respectively. Manuscript profile -
Open Access Article
8 - Comparison of Spatial Interpolation Methods to Mapp Heavy Metals Concentrations in Surface Soil of Aran-O-Bidgol City
Younes seifi Rouhollah MirzaeiBackground and Objective: Selecting a suitable interpolation method is a main factor of surface analysis and it is a difficult task in geostatistical analysis since different methods of interpolation can result in different surfaces and ultimately different results. Hen MoreBackground and Objective: Selecting a suitable interpolation method is a main factor of surface analysis and it is a difficult task in geostatistical analysis since different methods of interpolation can result in different surfaces and ultimately different results. Hence, the aim of this study is to evaluate the performance of different interpolation methods in determining the spatial concentration of Cd, Zn and Cu in the Surface soil of Aran-O-Bidgol City. Method: A total of 135 surface soil (0-20 cm) samples were collected in the study area and the soil heavy metals concentrations were determined. The spatial distribution of heavy metals concentration in Surface Soil of Aran-O-Bidgol was evaluated using different interpolation methods including ordinary Kriging, CoKriging, Inverse Distance Weighting, Local Polynomials and Radial Basis Function. Cross validation and MSE, MBE, RMSE, NSE, PBIAS were applied to estimate their accuracy. Findings: According to the results Ordinary Kriging (spherical model) had the best efficiency for estimating Cd and Cu concentrations and Ordinary Kriging (exponential model) had the best efficiency for estimating distribution pattern of Zn concentration in the soil of this region. The weight parameter has a significant influence on the accuracy of interpolation. The higher the order of local polynomial, the larger the accuracy of cross validation, whereas, the greater the weighting power of IDW for Cd and Zn, the greater error and larger accuracy of the interpolation will be for Cu. Discussion and Conclusion: Although all of the considered interpolation methods had a high prediction accuracy of the mean content for soil heavy metals, but taking all cross validation indicators into consideration, Ordinary Kriging (OK) method shows a generally better performance than other methods. Manuscript profile -
Open Access Article
9 - Modeling of Groundwater Quality Parameters Using Artificial Neural Network and Geostatistics Models (Case Study: Zeidoun plain)
Abdol Amir Echreshzadeh Aslan EgdernezhadBackground and Aim: One of the obstacles to develop sustainable is the poor quality of water. The assessment of water quality is usually based on chemical decomposition and measurement of chemical parameters of water. Measuring these parameters in big area is costly and MoreBackground and Aim: One of the obstacles to develop sustainable is the poor quality of water. The assessment of water quality is usually based on chemical decomposition and measurement of chemical parameters of water. Measuring these parameters in big area is costly and time-consuming, as result it required to estimating methods for prediction of those parameters. The purpose of this study is to model the groundwater quality parameters of Zeydoon plain using ANN+PSO and geostatistics models. Methods: For this purpose, the information of 42 observation wells in Zeidoon plain on a monthly basis for 7 years has been used. Neural network model inputs including qualitative parameters SO42- ، pH ، HCO32-، Na+، Mg2+، Ca2+، TDS، SAR and EC were considered. Findings: The results of simulation of groundwater quality parameters using ANN + PSO model showed that in SAR simulator model the highest simulation accuracy is related to the model with sigmoid logarithm function, in EC simulator model the highest accuracy is similar. The construction is related to the model with the stimulus function of the sigmoid tangent. Also, in the TDS simulator model, the highest simulation accuracy of the model with the sigmoid tangent stimulus function was obtained. As RMSE and MAE have the lowest value and R2 index has the highest value. The results of simulation of groundwater quality parameters using the geostatistical model showed that the highest accuracy of the kriging model in the simulation is related to EC, SAR and TDS parameters, respectively. Discussion and Conclusion: Finally, comparing the results of comparing the results of ANN + PSO model and Kriging model showed that ANN + PSO model is more accurate in simulating groundwater quality parameters of Zidon plain than Kriging model. Also, the results of this research showed that the combination of intelligent models with optimization algorithms with correct architecture and complete model inputs are used as a useful tool for simulating groundwater quality parameters. Manuscript profile -
Open Access Article
10 - Spatial distribution of (Ni, Cr, Pb, Cu and Co)in the Surface (Superficial) Soil of Hamadan county with Geostatistic & GIS
parisa Farzaneh ali reza Soffianian faramarz MoattarIntroduction: Heavy metals are one of the most important soil pollutants. The increased level of them in environment in respect to their stability has led to researchers’ attraction at recent decades. the principal goal of present study is to determin MoreIntroduction: Heavy metals are one of the most important soil pollutants. The increased level of them in environment in respect to their stability has led to researchers’ attraction at recent decades. the principal goal of present study is to determine the spatial distribution of heavy metals (Ni, Cr, Pb, Cu and Co) in surface soil of Hamadan county. Material and methods: For this Sampling was carried out based on systematic method from depth 0-20cm. heavy metals concentration and soil characteristics including PH, silt,clay and sand percentage were measured. Interpolation for heavy metals levels concentrations were done by geo-statistics methods . Different elements were interpolated through Radial basic function(RBF), Ordinary and Disjunctive Kriging and inverse distance weighting .The method accuracies were compared by using mean absolute error and mean bayas error. Results: for heavy metal concentration maps, Cr,Co and Pb, we used (RBF),for Cu inverse distance weighting(IDW),for Ni ordinary kriging with exponential model. Overplaying heavy metals distribution maps with geology and land use maps showed that Cr, Co and Ni have geological origin, The highest levels of Lead concentration is controlled by geological formation, agricultural activities and also urban pollution. Cu have originated from bed rock. But, excessive consumption of chemical fertilizers according to agricultural activities can increase most of these elements in soil. Manuscript profile -
Open Access Article
11 - Applying fundamental geostatistical approaches to determine potential zones of groundwater recharge of Tehran-Karaj Plain Aquifer
Behzad RayeganiGroundwater, especially in arid and semi-arid is one of the main sources of drinking water. Contrary to public perception in these areas the water quality is more important than quantify. Therefore, monitoring of water quality and identification of pollution sources is MoreGroundwater, especially in arid and semi-arid is one of the main sources of drinking water. Contrary to public perception in these areas the water quality is more important than quantify. Therefore, monitoring of water quality and identification of pollution sources is one of the main concerns of researchers in this area. In this study, in order to identify sources of groundwater contamination, areas are likely aquifer recharge sources of Tehran-Karaj plain detected. So, after extraction of groundwater level data different interpolation and geostatistics methods are used to create surface images. The Gstat software and Geostatistical Analyst were used for this study then performance and ability of each one to produce surface images are evaluated. According to the results, the Geostatistical Analyst software has better flexibility to do the special analysis. Based on the training and test data interpolation methods were very similar, but the surface images regarding groundwater direction flow and histogram look very different. According to the results, universal kriging showed better performance. Accordingly, surface images of different time created by an appropriate method to simulate groundwater flow direction and eventually areas were identified which are more likely ground water recharge source of Tehran-Karaj aquifer. Manuscript profile -
Open Access Article
12 - Spatial distribution of some heavy metals in two agriculture and rangeland uses (A case study: Shahzand industrial city, Arak)
Leila Zarei Soheila sadat Hashemi Mahdi Najafi GhiriSoil is a natural environment for plant growth and due to its importance, the study of heavy metal distribution for soil contamination monitoring and environmental quality maintaining is necessary. This investigation was performed to study the spatial variability of som MoreSoil is a natural environment for plant growth and due to its importance, the study of heavy metal distribution for soil contamination monitoring and environmental quality maintaining is necessary. This investigation was performed to study the spatial variability of some heavy metals in some surface soils of the Shazand City. A total of 76 soil surface samples were randomly collected from a depth of 0-30 cm in the study area. After preparation of the samples, some physico-chemical characteristics and the total amount of, lead (Pb), cadmium (Cd), nikel (Ni), zinc (Zn) and copper (Cu) were measured. Mean concentrations of Pb, Cd, Ni, Zn and Cu were 31.20, 54.12, 23.11, 2.05 and 59.36 mgkg-1, respectively. Significant correlations were found between Ni with Cu (r= 0.41, p<0.01) and Zn (r= 0.5, p<0.01). Also, a significant correlation was obsrved between Cu and Zn (r= 0.4, p<0.01). The spatial variability of these variables was examined by variogram models and ordinary kriging. The results of geostatistical analysis showed that the spherical model was the best model for describing the spatial variability of all studied elements. Strong spatial dependence (the ratio of nugget to sill less than 0.25) was obtained for the lead element. According to the standard limits, Pb and Cd showed the highest pollution in rangeland and agricultural land use in the study area, respectively. It’s recommended to increasing soil quality and reduces it’s degradation from pollutants applied proper environmental proceeding. Manuscript profile -
Open Access Article
13 - Multivariate geostatistical analysis in assessment of aerosols (Case study: Bushehr)
Tayebeh Tabatabaei Abdolreza Karbassi Faramarz Moatar Seyed Masoud MonavariThe mean aerosols samples in three periods of ten stations were taken from Bushehr region, to characterize the spatial variability and concentration of As, Cd, Co, Fe, Ni, Pb and V. The geostatistics and geographic information system (GIS) techniques were applied, and t MoreThe mean aerosols samples in three periods of ten stations were taken from Bushehr region, to characterize the spatial variability and concentration of As, Cd, Co, Fe, Ni, Pb and V. The geostatistics and geographic information system (GIS) techniques were applied, and the disjunctive kriging was used to map the spatial patterns of the seven heavy metals. Meanwhile, Principal component analysis (PCA) and correlation matrix (CA) were used for the data processing. The results of Nug/Sill ratios for the seven metals showed that spatial dependent is moderate (0.25-0.75), that indicative the effects of natural factors such as parent material and topography. Meanwhile, the disjunctive kriging technique was used to quantify their concentration distribution. Combined with the results of PCA, 7 heavy metals could be divided into 3 factors. D1 was the metals, i.e., As, Co, Ni, Pb, V. Cd was in D2, Fe in D3. This results show the concentrations of 7 heavy metals were mainly controlled by the external factors. These results will contribute to the management of regional environment. Manuscript profile -
Open Access Article
14 - Study of heavy metals concentration Copper, Zinc and Arsenic soil using RS and GIS techniques (Case study: Kaboudarahang, Razan and Khonjin- Talkhab catchment in Hamedan province)
Loghman Khodakarami Alireza Soffianian Elahe Mohamadi Towfigh Noorollah MirghafariIn this study, we investigated the effect of agricultural land concentrations of heavy metals including Copper, Arsenic and Zinc and mapping of soil contamination potential the elements in the areas studied using the collected data, GIS, Geo-statistics and remote sensin MoreIn this study, we investigated the effect of agricultural land concentrations of heavy metals including Copper, Arsenic and Zinc and mapping of soil contamination potential the elements in the areas studied using the collected data, GIS, Geo-statistics and remote sensing were conducted. First, using 135 surface soils (0-20cm) classified random systematic sampling in the region area 7262 square kilometers were collected and total element concentrations, soil characteristics, including the pH and organic matters were measured. Interpolation for heavy metals concentrations were done by geo-statistics methods, and assisting location correlation analysis, interpolation suitable method was chosen using MAE and MBE function. For heavy metals concentration maps, Copper and Zinc, we used Ordinary Kriging and exponential model and for Arsenic Ordinary Kriging and Spherical models. For analyzing the metal's concentration distribution maps of pollution time series satellite images were used. For this purpose, five time series of satellite images of IRSP6 sensor Awifs (6 March, 3 April, 27 April, 9 June, 18 July and 16 August) were prepared. Using conventional classification methods and advanced satellite imagery maps of Land Use in 2009 was prepared. Finally fuzzy classification method map due to having the higher kappa coefficient as a final land use map was selected. Site analysis of studied heavy metal interpolation maps assisted by GIS and remote sensing assistive showed that Copper and Zinc have geological and agricultural origins. And Arsenic has originated from bedrock, but agricultural activities according to excessive consumption of chemical fertilizers can increase most of these elements in soil. Manuscript profile -
Open Access Article
15 - Mapping of calcium carbonate equivalent and clay content of surface soil using geostatistical methods (Case study: Chitgar park, Tehran)
Ebrahim Mahmoudabadi Alireza Karimi KarouyehIn recent decades, remote sensing methods because of their economical aspects are frequently used in soil survey studies. The objective of this study was to compare the remote sensing and geostatistical methods for estimating and mapping the calcium carbonate equivalent MoreIn recent decades, remote sensing methods because of their economical aspects are frequently used in soil survey studies. The objective of this study was to compare the remote sensing and geostatistical methods for estimating and mapping the calcium carbonate equivalent and clay content of surface soil in the Chitgar Park with the area of 665 hectares. Therefore, 116 samples (0-20 cm) were taken by the intervals of 250 meters based on regular grid patterns. Two geostatistic methods of kriging and inverse distance weighting (IDW), and two remote sensing techniques of near-infrared analysis (NIRA) and Continuum removal (CR) were used for modeling the desired variations. The results of the cross validation showed that the accuracy of kriging was appropriate for modeling clayand calcium carbonate equivalent contents. The NIRA method due to the low correlation between TM bands and calcium carbonate equivalent was not validated for modeling the calcium carbonate equivalent; but this method was appropriate for estimating clay content (R2=0.52). CR method was not accurate for both variables of clay and calcium carbonate equivalent. Based on the overall accuracy and Kappa coefficient of producing maps, it is concluded that the kriging method has higher accuracy than remote sensing methods. Although high accuracy of geostatistic methods is expected due to the use of real data, the acceptable accuracy of the NIRA technique for modeling the clay variable should be considered with respect to lower costs of remote sensing methods. Manuscript profile -
Open Access Article
16 - Application of geostatistics in management of two spotted spider mite, Tetrantchus urticae Koch (Acari: Tetranychidae) in common bean fields
M. Hojjati A. Mohiseni R. Vafaei Shoushtari I. TermechiTwo spotted spider mite, Tetranychus urticae Koch is the most important pest of common bean in most areas of Iran, including Lorestan province. In this study the geostatistical charachteristics of this pest were evaluated in Borujerd common bean fields in 2009. To do th MoreTwo spotted spider mite, Tetranychus urticae Koch is the most important pest of common bean in most areas of Iran, including Lorestan province. In this study the geostatistical charachteristics of this pest were evaluated in Borujerd common bean fields in 2009. To do this research, two red common bean (Goli variety) fields that each one was about four hectares were selected. In each field, about 300 points (stations) were identified and marked. Sampling was started in mid July. At each station on three point of plant height (bottom, middle and top) three leaves were sampled. In the laboratory, the samples were observed and mite population density were counted with respect to each life stage. Results showed that the spherical model provided the best fit (based on r2-values) for the semivariogram data in 20 data sets out of 25 at the beginning of the pest attak in late July and early August. In this time, nugget/sill ratio was very low and by passing the time this ratio increased so that the spatial dependence among points decreased. Thus in August and early September more semivariogram curves fitted with the model of pure nugget effect and did not show any spatial corrdation among points selected in the fields. The effective range of spatial correlation of this pest were relatively high at the beginning of the pest attack. This range for adult females, nymphs and eggs were 357-641, 510-710 and 610-711 meters respectively. These distances were reduced by passing the time and by approaching end of season. Based on these results, application of geostatistics is recommended to monitoring and forecasting of two spotted spider mite, T.urticae in common bean fields at the beginning of the pest attack. Manuscript profile -
Open Access Article
17 - برآورد نیاز آبی محصولات کشاورزی در استان خوزستان
کاظم حمادی فاطمه ذاکرحسینی سید محسن حسین زاده ساداتی سروش اله دینیکی از گام های مؤثر در استفاده از منابع آب، برآورد صحیح مقدار آب مورد نیاز گیاهان می باشد، عدم برآورد صحیح این مقدار منجر به هدر رفت آب و عدم دستیابی به پتانسیل عملکرد مطلوب، کاهش پتانسیل تولید، تخریب منابع خاک با آبیاری زیاد و یا عدم آبشویی کافی و شور شدن خاک ها در اثر Moreیکی از گام های مؤثر در استفاده از منابع آب، برآورد صحیح مقدار آب مورد نیاز گیاهان می باشد، عدم برآورد صحیح این مقدار منجر به هدر رفت آب و عدم دستیابی به پتانسیل عملکرد مطلوب، کاهش پتانسیل تولید، تخریب منابع خاک با آبیاری زیاد و یا عدم آبشویی کافی و شور شدن خاک ها در اثر آبیاری کمتر از حد لزوم خواهد شد که این امر نهایتاً توسعه پایدار کشاورزی را به مخاطره خواهد انداخت. این مقاله با به کارگیری اطلاعات بیش از 40 ایستگاه، هواشناسی، تبخیرسنجی و سینوپتیک به محاسبه تبخیر و تعرق پتانسیل گیاه مرجع، بارندگی موثر، نیاز آبی گیاهان گندم، ذرت، نیشکر، هندوانه و گوجه پرداخته است و با اعمال راندمان های مختلف نیز نیاز آبی ناخالص محاسبه شد. از آن جایی که محاسبات به صورت نقطه ای و ایستگاهی انجام گرفته است؛ این یافته ها با استفاده از تکنیک های زمین آماری در محیط GIS در سطح استان خوزستان گسترش یافت. در نهایت نشان داده شد که بهبود مصرف در راندمان های پایین باعث کاهش نیاز آبی بیشتر نسبت به راندمان های بالاتر می شود و لذا مدیریت مصرف در گام های اولیه بازدهی بیش تری دارد. Manuscript profile -
Open Access Article
18 - پهنهبندی هدایت هیدرولیکی با استفاده از روشهای مختلف زمین آمار (مطالعه موردی منطقه شاوور)
محمد سلاخ پور عباس ملکی علی مختاراندر مطالعات طرح ‎های آبیاری و زهکشی برای زهکش‎ های زیرزمینی، ضرورت دارد اطلاعات حاصل از نمونه برداری نقطه‎ ای به سطح شبکه تعمیم داده شود. لذا بر اساس داده ‎های چاهک‎ های مشاهده ‎ای موجود، وضعیت داده ‎های هدایت هیدرولیکی (K) در مناطق مجاور برآو Moreدر مطالعات طرح ‎های آبیاری و زهکشی برای زهکش‎ های زیرزمینی، ضرورت دارد اطلاعات حاصل از نمونه برداری نقطه‎ ای به سطح شبکه تعمیم داده شود. لذا بر اساس داده ‎های چاهک‎ های مشاهده ‎ای موجود، وضعیت داده ‎های هدایت هیدرولیکی (K) در مناطق مجاور برآورد شود. در این تحقیق بر اساس داده‎های 49 عدد چاهک مشاهده‎ ای احداث شده در دشت شاوور در استان خوزستان، داده‎ های نقطه‎ای به روش چاهک (ارنست)، به سطح شبکه تعمیم داده شد و سپس با استفاده از روش‎ های علمی شامل انواع روش کریجینگ، تیسن و میان‎ یابی وزنی، میزان دقت روش‎ های مختلف درونیابی با هم مقایسه شد. با توجه به مختصات موقعیت جغرافیایی چاهک‎ های مشاهده‎ای، نقشه رقومی ضریب آبگذری محدوده مطالعاتی، با استفاده از نرم افزار Civil 3D، تهیه شد. سپس مراحل مدل سازی فضایی در محیط نرم افزاری ArcGis و ArcMap انجام شد. به جهت مقایسه با سایر روش‎ های آماری از نرم افزار GS+ استفاده شد. با ترسیم روش ‎های دیگر آماری توسط نرم افزار GS+ و ArcGIS و ArcMAP ،روند تغییرات مکانی در حالت کریجینگ معمولی، از کم ترین خطا برخوردار بود. لذا در این تحقیق، برای پهنه‎بندی و تعمیم هدایت هیدرولیکی از روش میان‎یابی کریجینگ معمولی استفاده شد. در نهایت، در این پژوهش منطقه مورد مطاله در سطح 11500 هکتار به روش کرینجینگ معمولی به سه ناحیه ضریب هدایت هیدرولیکی با وسعت های 2300 هکتار کمتر از دو متر بر روز،7900 بین دو تا سه متر بر روز و 1300 هکتار بیشتر از سه متر بر روز پهنه‎بندی شد. با توجه به نتایج حاصل شده، محاسبه فاصله کارگذاری زهکش‎ های زیرزمینی در سه ناحیه 50،70 و 80 متر برآورد شد. همانگونه که ملاحظه می شود، چنانچه در تخمین محدوده گستره طرح جهت ضریب آبگذری، از روش غیر معتبر و دارای خطا استفاده شود، چه بسا باعث تشدید هزینه در طرح‎ های شبکه های زهکشی به سبب خطای برآورد فاصله کارگذاری زهکش‎ های زیرزمینی شود. Manuscript profile -
Open Access Article
19 - Monitoring and predicting the groundwater-level fluctuations for better management of groundwater resource in Lowlands Using Geographic Information System (GIS)
Abolfazl Bameri Moazam Khaleghi In order to be aware of groundwater-level fluctuations in arid and semi-arid regions, it is necessary to make an accurate forecast of the groundwater depth situation. The drying of Hamoon lake, severe water shortages and significant reduction in groundwater levels More In order to be aware of groundwater-level fluctuations in arid and semi-arid regions, it is necessary to make an accurate forecast of the groundwater depth situation. The drying of Hamoon lake, severe water shortages and significant reduction in groundwater levels have led to critical environmental conditions in the Sistan plain. Spatial understanding of groundwater depth changes in the region and awareness of the severity of groundwater depletion are important for the development of water resources management strategies. Therefore, this study was conducted with the aim of zoning groundwater depth using geostatistics and GIS techniques in the agricultural lands of Sistan plain located in the east of Hamoon Lake, with an area of about 201000 ha. For this purpose, groundwater depth data were collected from 846 wells by field survey using piezometric wells in the study area. In this research, various geostatistical methods including deterministic interpolation method and geostatistical methods were evaluated to compare the prediction ability of groundwater depth spatial variations. The results showed that the intensity of groundwater depth changes in the study area with a coefficient of variation of 19.87% is moderate. The spherical model could better explain the spatial variation of the experimental variogram of the studied parameter in the region. Finally, the results related to the deterministic method of inverse distance weighted with power 2 estimates a better prediction for groundwater depth zoning than kriging and cokriging geostatistical methods. Manuscript profile -
Open Access Article
20 - Investigating spatial and temporal changes in the quality of underground water sources in the Izadkhash basin
Maryam Ansari ایرج جباریThe increase in the world's population, the effects of climate change and lifestyle changes have put increasing pressure on water resources and have led to widespread water stress in many countries. An effective way to reduce and control the continuous degradation of gr MoreThe increase in the world's population, the effects of climate change and lifestyle changes have put increasing pressure on water resources and have led to widespread water stress in many countries. An effective way to reduce and control the continuous degradation of groundwater quality is to understand spatial and temporal changes and identify the main sources of pollution. In this research, using the geostatistical method, temporal and spatial changes in the underground water resources of Izadkhasht basin were investigated in a period of 11 years, considering the factors of water quality change. In this regard, different interpolation methods were compared, and the kriging method with exponential variogram showed better results for water quality parameters. The results of these analyzes showed that the most important factors in the salinity of water and soil resources in the region are destructive formations in the basin. So that in the quality maps of water resources, all parameters showed an increase in three points. Manuscript profile -
Open Access Article
21 - Assessment of Saltwater Pollution in Azarshahr Plain Groundwater, Iran: Conjugating GALDIT Method and Geostatistics
Alireza Docheshmeh Gorgij Asghar Asghari Moghaddam -
Open Access Article
22 - Modeling of Artemisia sieberi Besser Habitat Distribution Using Maximum Entropy Method in Desert Rangelands
Hossein Piri Sahragard Mohammad Ali Zare Chahouki -
Open Access Article
23 - Comparing Deterministic and Geostatistical Methods in Spatial Distribution Study of Soil Physical and Chemical Properties in Arid Rangelands (Case Study: Masileh Plain, Qom, Iran)
Noredin Rostami Vahid Habibi Raed Kamali Moghadam
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