نشریه پژوهشهای خاک (علوم خاک و آب)
سال بیست و هشتم شماره 1 (بهار 1393)

In Qom province، two thousand hectares are under canola cultivation، of which more than half suffer from different degrees of soil and water salinity. Nitrogen is one of the most important nutrients necessary for canola، especially in saline condition. There is no precise information about N nutrition for canola in saline condition. In order to study the effect of different N rates on growth and yield of two cultivars of canola in saline condition، during 2006-2007، two field trials were conducted in two sites in Qomroud district of Qom province. In the first farm، irrigation water and soil salinity levels were، respectively، 5. 5 and 5. 8 dS. m-1، and in the second site، the corresponding salinity levels were 8. 3 and 8. 1 dS. m-1. In each site، the trial was conducted with six levels of N and two canola cultivars in a split plots experiment with randomized complete blocks design and three replicates. Sub plots included nitrogen in six levels (i. e. 0، 45، 90، 135، 180 and 225 kg N. ha-1 as urea source) and the main plot was allocated to two canola cultivars، namely، Hyola-401 and PF varieties. The results showed that، for both cultivars and both irrigation water salinity levels، increasing N level up to 225 kg N. ha-1 enhanced seed yield، dry mater، and oil yield significantly (p<0. 05) in comparison with the control (no nitrogen application) and as well as the other N levels; however، the seed oil content decreased (p<0. 05). The Hyola-401 variety had comparative preference to PF variety in seed yield and oil content. Interaction between varieties and N levels was not significant. The highest seed yield was obtained in 225 kg. N. ha-1 at both salinity levels، whereas in PF variety in second salinity level، there was no significant difference between 180 and 225 kg. N. ha-1 at 5% level in Duncan test.

The chemical and biological conditions in the rhizosphere can be different from those in bulk soil. This could alter the quality of the diagnosis of nutrient bioavailability. Phosphorus (P) is one of the primary limiting factors of plant growth in arid areas. The objective of this research was to study the status of various inorganic phosphorus (Pi) fractions، organic phosphorus (Po)، acid and alkaline phosphatase enzymes (AcP and AlP، respectively)، microbial biomass phosphorus (MBP)، and dissolved organic carbon (DOC) in the rhizosphere and the bulk soils of wheat plant growing in 10 calcareous soils in a rhizobox experiment. Thus، P fractions، including P absorbed by Al and Fe oxides (]NaOH+CB]-Pi)، occluded P (CBD-Pi)، P bounded by Ca (Ca-Pi)، and residual P were determined by modified Olsen and Sommers'' sequential fractionation procedure. The results showed that phosphatase activities، MBP، and DOC strongly increased in the rhizosphere soils compared with the bulk soils. Also، the pattern of distribution of the Pi fractions differed between the rhizosphere and the bulk soils. The results showed that the amount of the various P fractions in the rhizosphere and the bulk soils decreased in the following order: Ca-Pi> residual-P> organic P>]NaOH+CB [-Pi> CBD-Pi. Simple correlation coefficients showed that plant indices had positive relationship with] NaOH+CB[-Pi، CBD-Pi fractions، MBP، and AlP in the rhizosphere soils (P≤0. 05). The results indicated that P in the rhizosphere was concomitantly modified but the inner-conversion of different fractions and the mechanisms involved were less clear.

In order to study the effects of crop rotation and different systems of fertilization on soil chemical and biological properties and grain yield of canola (Brassica napus L.) Talayeh cultivar، an experiment was conducted at experimental farm of Agricultural Research Center of Sanandaj during 2007 - 2010 growing seasons. Experimental design was arranged in split plots based on randomized complete blocks design with three replications. Main plots contained three crop rotations including (R1): chickpea، sunflower، wheat، canola; (R2): green manure، chickpea، green manure، wheat، green manure، canola; (R3): canola، wheat، canola. Sub plots were allocated to five strategies for provision of the basal fertilizers requirement and included (N1): farm yard manure; (N2): compost; (N3): chemical fertilizers (Urea، triple super phosphate and ammonium phosphate); (N4): farmyard manure + compost and (N5): farmyard manure + compost + chemical fertilizers; and control (N6). Results showed that simultaneous application of manure، compost and chemical fertilizers increased soil mineral elements (N، P، and K). Application of legume green manure in R2 rotation effectively increased nitrogen، phosphorus، and potassium of soil، number of bacteria، microbial carbon biomass، and also dehydrogenase and protease enzymes activity in comparison with the other rotations. The greatest number and biomass of microbial community was observed in the N4 treatment (farmyard manure + compost). The highest enzyme activity (phosphatase، protease، urease and dehydrogenase) occurred in N4 treatment. The lowest activity of dehydrogenase and protease was achieved from the R3 treatment. Green-manure crop rotation (R2) increased activity of these enzymes significantly. Most urease activity (48. 6 µg urea g-1dry soil) was achieved in the R2N4 treatment. The highest grain yield was observed in R2 and N5 treatments. The R2N4 treatment was selected as the best treatment in this experiment.

Stratification ratio of soil organic matter and aggregate stability are considered as indicators of soil quality under different conditions such as burning rangeland vegetation. The objective of this study was to investigate the impact of fire on stratification ratio of soil organic matter and aggregate stability and distribution of organic matter in two macro and micro fractions in semi-steppe rangeland of Karsanak region in Chaharmahal and Bakhtiari province. Several sites which were affected by fire three، two، and one years before this study (i. e. 2008، 2009، and 2010، respectively) were chosen. Since the soil samples were taken from two depths (0-10 cm and 15-25 cm) of each site with 9 replications، the numbers of soil samples for laboratory analysis were 108. Independent t-test (P= 5%) was used to assess the difference between the measured properties at the burned and control sites. The results showed that the soil organic matter and mean weight diameter of aggregates (MWD) in the surface layer decreased significantly in 1 and 2 years after fire. Particulate organic matter (POM) significantly decreased in surface layer of the burned areas compared with the control areas. The effects of fire on stratification ratio of soil organic matter in 1- and 2-years after fire were significant compared with control areas، and stratification of soil organic matter decreased 26% and 22 percent in 1 and 2 years after fire، respectively. Stratification ratio of aggregate stability was lower in all burned areas compared with control areas، but the differences were not significant. Macro organic matter of both surface and subsurface layers in 1 year after fire was significantly reduced compared with the control، while، micro organic matter of subsurface layer showed significant increase. The study results showed that the effect of fire on physical and chemical soil properties in the surface layer were more than subsurface layer، because of higher-severity fire in surface layer. Furthermore، due to reduction of organic matter and aggregate stability after fire، rangeland soil quality decreased.

Soil organic carbon (SOC) storage estimation with high accuracy is very important due to having such prominent role corresponding to climate change and global warming reduction. Therefore، the current study was carried out in the beech mixed-stands forest of reserved compartment in Glandrood forests، in the northern parts of Iran. Stepwise regression method was used in order to present the SOC pool weight modeling considering the prominent soil physic-chemical properties at 3 different soil depths (0-10، 10-30، and 30-50 cm). The results of ANOVAs showed that exchangeable calcium content، lime and clay percentage (P < 0. 05) and also carbon content، soil organic matter، nitrogen and C/N ratio (P < 0. 01) were significantly different among the three soil depths. Moreover، on average، the total soil carbon stored considered as SOC pool weight in the ecosystem equaled 543. 87 ± 22. 07 t. C ha-1. According to the stepwise regression analysis C/N ratio was the effective content as explanatory variable to predict SOC pool (R2adj = 0. 44; SEE = 4. 8). In the following models، P، N and clay percentage، respectively، were the effective contents which improved significantly SOC pool prediction (R2adj = 0. 64-0. 83; SEE = 3. 8-2. 6). C/N ratio، P، N and clay were included 46. 3، 22. 41، 14. 71 and 9. 44 percent respectively with respect to the variations of SOC pool. Regression analysis indicated that introducing electrical conductivity، pH، and Mg as input variables in the following steps did not ameliorate the precision of SOC pool prediction clearly (R2adj = 0. 85-0. 89; SEE = 2. 5-2. 1). Furthermore، during the modeling and according to the collinearity diagnostic test، the result indicated that the maximum variance inflation factor of the models was less than 10 (VIF < 10)، validating them for application.

The bioavailability and ultimate fate of heavy metals in the environment are controlled by chemical sorption. In this study، sorption characteristics of Cd in 19 calcareous soils of Iran were assessed at varying Cd concentrations (0. 024-12. 8 mM Cd) and 25°C. Sorption isotherms were well described by the Langmuir and Freundlich equations (R2= 0. 95-1. 00 and R2= 0. 94-0. 99 for Langmuir and Freundlich models، respectively). The maximum adsorption capacity of soils ranged from 2460 to 10226 mg kg-1. Soils with higher clay content had greatest sorption capacity as estimated by the maximum sorption parameter of the Langmuir equation. The results revealed that cation exchange capacity (CEC)، clay، sand، and OC were the most important soil properties affecting Cd adsorption behavior in calcareous soils. Maximum adsorption parameter of Langmuir and Freundlich constant coefficients were significantly correlated with clay، sand، silt، CEC، and OC. However، No statistically significant relation was found between the model parameters and calcium carbonate equivalent (CCE)

Nowadays، mathematical models are commonly used as efficient tools in solute transport studies and management in porous media. In this study، the developed and improved Advection-Dispersion Equation (ADE) model known as Fractional Advection-Dispersion Equation (FADE)، which is based on the theory of Levy motion، was used to simulate the transport of bromide through undisturbed clay loam and sandy loam soil columns (10 cm in diameter and 40 cm long). The quantities of fractional order (α) for clay loam and sandy loam soil columns were derived at 1. 437 and 1. 865 (less than 2)، respectively. This indicated that the bromide transport behaviour within the clay loam and sandy loam soil columns was anomalous transport or non-Fickian transport and FADE model was more suitable for simulation of bromide transport through undisturbed clay loam and sandy soil columns compared to ADE model with Fickian diffusion law basis. The graphical and statistical analysis confirmed the efficiency of FADE model for simulation of bromide transport. Despite high accuracy of FADE model in this research، there was no appreciable difference between FADE and ADE models.

mouseover=«function onmouseover() {msoCommentShow (''_anchor_1''،''_com_1'')}» onmouseout=«function onmouseout() {msoCommentHide (''_com_1'')}» href= «#_msocom_1» > [H1] The objective of this study was to investigate the effect of time and concentration on bioavailability of added Cd and Pb to one acidic and three alkaline soils. The soils were treated with five different concentrations of Cd and Pb and incubated at 85% field capacity and constant temperature of 25 ° C for one year. Samples were taken at certain intervals and extracted by DTPA method. Results showed that decrease in Cd and Pb bioavailability were initially rapid followed by a slower rate at longer time. Time dependence of Cd and Pb bioavailability in different concentrations had a similar pattern، except for 5000 mgPb kg-1. After one year، the bioavailability of soil-added Cd and Pb decreased 50. 4% and 57 % in alkaline soils and 35. 4% and 42% in acidic soil، respectively. bioavailability increased with increasing soil-added Cd and Pb levels، but this increase was linear for Cd and nonlinear for Pb. Comparison of coefficients of determination (R2) showed that the modified Probert- Larsen equation was able to describe the results (R2=0. 92 to 0. 99، p<0. 001).

Using models to interpret soil-water-plant relationships under different conditions enable us to study the different management scenarios and then determine the optimum option، which help us to reduce the costs and to improve the benefits. As experimental studies are time consuming and expensive and the results are often affected by uncontrollable environmental conditions، using models to describe the complicated relationships between soil، water، and plant can be a suitable solution. The aim of this study was to use WAVE Model to predict nitrogen balance components and simulation of soil water reserve over a corn crop season in 2007 and also in the period between 2007 harvest and the next crop of 2008. This study was done in the Irstea experimental station in the Southern France in 2007-2008 period. Results showed an appropriate agreement between measured and model simulations of leaf area index (r2=0. 95)، soil water reserve (r2=0. 96)، and final soil nitrogen content (by maximum difference of 0. 6 kg N. ha-1). Also، in calibration process for soil water reserve simulation، according to nRMSE and NSE indices، which were، respectively، 7 % and 0. 95، the performance of the model was excellent.

The process-based WEPP model can predict all effective variables of soil erosion physically using mathematical equations، especially in arable lands. The main objectives of this study were to determine the capability of hill-slope version of WEPP model in runoff and soil erosion estimation on rainfed lands and its potential in simulating the different management practices effects on soil erosion. This research was conducted in rainfed area of Kabode region، across the Gharasoo watershed. Runoff and sediment collection plots with dimension of 10×3 meter in three replications were installed on the slopes of 6%، 12%، 16%، and 20%. Climate data recorders including rain gauge and Maximum and Minimum temperature recorders were installed in the site to record daily climate data. Additional climate data requirements including wind velocity and direction، solar radiation، and dew point temperature was obtained from Kermanshah synoptic station. Soil erosion and runoff was estimated in each plot for different hill slopes by the v2008. 9 version of WEPP. Results from the model assessment indicated that the runoff prediction accuracy was increased with increasing slope steepness such that the negative values of Nash-Sutcliff index in the 6% and 12% slope and the high RMSE’s of، respectively، 3. 16 and 4. 82 liter indicated lower accuracy of the model in runoff prediction for these slopes. In all plots، with the exception of plots on 6% slope، runoff was under- estimated. Also، maximum accuracy for soil erosion prediction was in 16% slope plots and the minimum efficiency of the model was in 20% slope، where the under-estimation error was 7. 5 kg per plot per year and the values of Nash-Sutcliff index were negative.

Performance of land suitability evaluation and land production potential prediction are very important in land use planning. The study region with a surface area of about 3050 hectares is located in Aghili plain، Gotvand، Khuzestan province، between 32° 07¢and 32° 10¢ N latitude and 48° 52¢ and 48° 56¢ E longitude. The aims of this research were to compare effects of corrected and uncorrected land indices on land suitability classes and accuracy of land production potential prediction. Land index was calculated using Storie and square root formulas. Based on the obtained results، the corrected land indices calculated by Storie and Square Root formulas of parametric method showed higher values compared with uncorrected ones and upgraded land suitability classes. The share of land suitability classes S1، S2، S3، and N، using square root formula for uncorrected land indices، were determined as، respectively، 0. 0%، 88%، 9%، and 3%. These values using the corrected land indices were obtained as، respectively، 32%، 63%، 5%، and 0. 0%. The share of land suitability classes S1، S2، S3، and N، using Storie formula for uncorrected land indices، were، respectively، 0. 0%، 4%، 55% and 5%. By using the corrected land indices، these percentages were obtained as، respectively، 55%، 38%، 6%، and 1%. Another conclusion was that the upgrading of the land suitability classes was more when Storie formula was used for the corrected land index، compared with the square root formula. This higher upgrading is more in accordance with conditions of the studied area. For validation of the methods used in this research، regression correlation was established between predicted yield for corrected and uncorrected land indices، using both Storie and square root formula and the observed yield. Root mean squared deviation (RMSD) was also used for evaluation of the methods and showed the higher accuracy of uncorrected square root method، with RMSD= 738 kg/ha، compared to other methods.

Saturated hydraulic conductivity (Ks) and drainable porosity () are two important parameters for designing subsurface drainage systems under unsteady-state flow conditions. In this study، an inverse method was developed to estimate the optimal values of Ks and. In the proposed inverse method، a genetic algorithm was used as an optimization technique. The drainage equation used in this research was Glover-Dumm equation. In order to measure the data required for calibration and evaluation of the developed inverse method، a sand box was designed and constructed in the laboratory. Also، the values of Ks and were measured directly. The water table height between the two subsurface drains was simulated by using the values of Ks and obtained from inverse method and direct method. The comparison of water table profiles indicated that predicting the water table profile using the values of Ks and obtained from inverse method was more accurate. In addition، the value of RMSE index decreased significantly using inverse method. Thus، this method was more exact. Therefore، it appears that the inverse method presented in this study is a highly efficient approach for estimating the values of Ks and.

The purpose of this study was to assess WINF and BLR methods application for mapping of landslide zonation in Pahne-kola sub-watershed located in the south of Sari، Iran. For this purpose، after field investigation and review of similar studies، 8 factors، including hypsometry، precipitation، slope، aspect، land use، distance from roads، soil and lithology، were identified as the effective factors of land slide. Later، the information layers of these factors and information layers of landslides of this region were prepared in GIS. These information layers were adapted with land slide distribution layer and the landslide information layer was obtained as a quantitative information layer. Afterwards، by using WINF and BLR methods، the landslide zonation map was created in GIS. Finally، application of the two methods was assessed by comparison with the frequency of landslide percent on high hazard classes (high and very high hazard). The results showed that for WINF and BLR methods، respectively، 72. 2% and 65. 56% of the landslides were in the high and very high classes. Therefore، the WINF method is better than the BLR method.

Accurate measurement and mapping of leaching fraction (LF)، as a key parameter in saline irrigation management، is a time consuming and expensive process. This research was carried out in 62 ha of Ardakan pistachio orchards of Yazd province in 2012 for measuring and mapping of LF through integration of the data obtained from Wetting Front Detector (WFD) and Electromagnetic induction (EM38) devices. For this purpose، 24 WFDs were installed in the region to extract root zone leachate waters and to measure their electrical conductivities (ECdw) as well as chemical constituents (Cl، Na، K، Ca and Mg). Soil samples were also collected in these points for ECe measurements. Additionally، ECe in 90 points were measured with the aid of EM38 and used for mapping of soil ECe. After calculation of LF as ECiw/ECdw، relationships between LF and soil ECe was modeled as LF=f (ECe). After statistical evaluation of the equation، it was applied to the ECe map to generate final LF map. Drainage water analysis showed that Na and Cl were the dominant ions in leachate waters (71. 6% and 74. 6%، respectively)، as well as in irrigation water. Also، good agreement was found between LF and soil ECe values with R2=0. 67 and RMSE=0. 054، which led to generation of final LF map. This map، as a demonstration of irrigation management، can be used for planning of irrigation and also improvement of existing management strategies in the studied area.

Temperature is an important soil physical parameter and could control soil physical and chemical processes as well as the growth and yield of crops. The aim of the present study was to use the sinusoidal model for predicting soil temperature in four selected synoptic stations with different climate، namely، Bandar Abbas، Rasht، Shahrekord، and Yazd stations. Soil surface (5 cm) daily temperature was collected during ten years period i. e. 1998 to 2007. For modeling، data set was divided into two parts: 70% for training and 30% for validation. To eliminate the effects of local climate variations on modeling process، data set of 1998 to 2002، 2004 to 2005 and 2007 were chosen for modeling. Daily data set of 2000، 2003 and 2006 were used for model evaluation. Two input parameters of sinusoidal model including mean and annual ranges of temperature were calculated using arithmetic mean، minimum، and maximum temperatures of the data set. Validation indices including RMSE، MBE، MPE، d، and R2 calculated for the four stations were، on average، 2. 64، -0. 16، 10. 84، 0. 59، and 0. 93، respectively. The result of sinusoidal modeling showed that the model efficiency decreased for Bandar Abbas، Yazd، Shahrekord، and Rasht stations، respectively.

Volume of vertisols changes by variation in soil water content and it causes re-arrangement of soil pores. Shrinkage curve shows the relation between soil porosity and soil moisture. Many models are presented to quantify shrinkage curve. The objective of this study was to evaluate McGarry and Malafant، Groenevelt and Grant، Peng and Horn، and Cornelis et al models for estimating shrinkage curve of some swelling soils of Dashte Zarrin، Chaharmahal-o- Bakhtiari province، Iran. Therefore، 35 soil samples were randomly selected from 0-30 cm depth of the selected site. Soil shrinkage curves were measured using pressure plate apparatus. The mentioned models were fitted to the measured shrinkage curve data. Then، performance of the models was evaluated using root of mean square error (RMSE)، mean error (ME)، absolute value of mean error (AME) and Akaike information criterion (AIC). Results showed that the models could describe most parts of the variation of shrinkage curve in the study soils. However، Groenevelt and Grant model with the AIC equal to -57. 29، RMSE of 0. 00052 cm3. cm-3، ME of -0. 00122 cm3. cm-3، and AME equal to 0. 0054 cm3. cm-3 was the best model. McGarry and Malafant model had the lowest performance، with AIC equal to -48. 82 and RMSE، ME and AME values equal to 0. 0122، 0. 00342 and 0. 0101 cm3. cm-3، respectively. Thus، for predicting the soils shrinkage curve of the study site، application of Groenevelt and Grant model is suggested.

Accurate، rapid، and low-cost instruments for in situ measurement of soil physical properties can simplify generation of their maps in different scales for site specific management of soil and water resources in these areas. One of these instruments is electromagnetic induction device (EM38) that has shown many capabilities in determination of some soil physical properties، both at the surface and in depth. Main objective of this study was to investigate EM38 capabilities in determination of some soil physical properties such as weighted and volumetric water contents (12θm «> and 12 θv)»>، clay، silt، and sand percentages، temperature، apparent bulk density (12ρb«>)، and porosity (n) in saline pistachio orchards of Ardakan، Yazd province. For this purpose، 90 EM38 reading points and 25 soil sampling points were selected in the region. Disturbed and un-disturbed soil samples were collected from four discrete depths (0-30، 30-60، 60-90، and 90-120 cm) and the mentioned parameters were determined. Afterwards، relationships between EM readings and different soil properties were calculated through simple and multiple regression methods. Results of this study showed no significant correlations between EM38 readings and clay، sand، silt contents and temperature، while significant correlations were found between horizontal EM38 readings (EMh) and 12 ρb»> with R2 of 0. 68 and 0. 65 for 0-30cm and 0-60cm soil depths، respectively. Additionally، relationships between EM38 and 12θv «>of 0-30cm، 0-60cm، and 0-90cm soil depths were significant with R2adj of 0. 69، 0. 74 and 0. 78، respectively. Based on these relationships، maps of 12ρb،» > 12θv«> and porosity (n) of different soil depths were prepared and interpreted. Results of this study، however، show suitability of EM38 instrument for low-cost and rapid mapping of some soil physical properties such as moisture، bulk density، and porosity.

Mineralogy، as one of the most important characteristics of soils، varies according to topography. Each clay mineral has unique properties، which influence the overall properties of the soils. The objective of the present study was to investigate soils clay mineralogy in relation to geomorphic surfaces in Sarduieh-Jiroft area. Soil moisture and temperature regimes of the area are xeric and mesic، respectively. Rock pediment، hill، mantled pediment، alluvial plain، and lowland landforms were indentified. Each landform was divided into different surfaces due to geomorphic stability. One representative pedon was studied and sampled on each geomorphic surface. Clay mineralogy analyses were performed on soil samples. The results showed that illite، chlorite، smectite، vermiculite، palygorskite and kaolinite clay minerals were present. Smectite mineral was dominant in the soil of the region as the product of illite and chlorite weathering، and، in lowland surfaces، it had authigenic source. Palygorskite was observed in the stable mantled pediment surface and in calcic horizon. Vermiculite mineral were formed in the lowland due to high humidity of illite mineral transformation. Chlorite، illite، and kaolinite clay minerals seemed to have been inherited from parent material.

One of the most important legume forages of Iran is alfalfa، which annually covers more than 600 thousand hectares of arable land. This plant is capable of fixing significant amounts of molecular nitrogen، if Sinorhizobium meliloti bacteria exist in the soil and suitable climatic and soil conditions prevail. In order to isolate and study the effect of different strains of S. meliloti on alfalfa yield، 20 soil samples were taken from different fields in Karaj and were planted to alfalfa in the green house. Later، 32 strains related to S. meliloti were isolated and 20 of which were confirmed، using the contamination test. To study the effect of these 20 different strains on alfalfa yield and to compare with applied nitrogen fertilizer in the presence of S. meliloti bacteria، an experiment was done using factorial treatments with completely randomized design in three replications (total of 72 treatments). Treatments were (inoculation، no-inoculation، and nitrogen fertilizer). Results of soil analysis showed that the amount of P، B، Fe، and Zn in most of alfalfa fields was less than critical level. Deficiency of these elements was one of the limiting factors of yield and nitrogen fixation in the field. The greenhouse experiment results showed that the effects of inoculation and nitrogen fertilizer on yield were significant (P<0. 05). Also، the effect of nine isolates on height of plant and fresh and dry weight of roots were significant compared to the control، while 10 isolates had significant effects on the nodules weight. Application of nitrogen fertilizer decreased nodulation significantly (P<0. 05) compared to the control and the inoculated treatments. The S11 treatment، which had the highest mean of shoot dry matter (1. 38g)، was in the same statistical group with S9 (with the average of 1. 36 grams) and both treatments showed a significant increase compared to the control. The S17 had the lowest average dry weight (0. 77 g).

Wind is the most important factor of erosion in arid regions. Movement of soil by wind is a complex phenomenon that is under the influence of some factors such as climatic and geomorphological conditions. This research was performed to identify dunes morphology، physical and chemical characteristics، and mineralogical specifications of Abardej''s sand dunes in southeast of Tehran province، Iran. At the first stage، different characteristics of the sand dunes were studied such as dunes morphology، kind of sands granulation، form of sand gravels، and so on. Based on these observations، the morphology of the dunes was transverse، indicating the existence of a dominant wind in one direction. Chemical analysis of Abardej''s dunes showed no important limitation for cultivation of plants. The main minerals of the dunes gravels were quartz، feldspar and calcite. Based on morphoscopic study، gravels of the sand dunes had steep angles. This result showed that the dunes had local sources. The sand gravels were almost shiny and halo، indicating that the dunes came from river - beds. The mean of sand gravels'' diameters was about 200 micron and about 20-25 percent of the gravels had diameters about 250 microns or more. This point، too، showed that the dunes had a local and nearby source.