مجله تحقیقات آب و خاک ایران
سال چهل و هفتم شماره 2 (پیاپی 25، امرداد و شهریور 1395)

van Genuchten model is a well-known and most widely used model for the estimation of soil water retention curve. The parameters of this model have been estimated by different estimators such as soil texture. But so far the properties of compaction curve have not been used to estimate the parameters of van Genuchten model. Compaction curve is one of the soil mechanical properties and shows the relationship between the stress-strain with the elasticity modulus. Soil water retention and compaction curves have similarities. Measurement of soil water retention curve is time-consuming and costly while the measurement of compaction curve is cheap and needs less time. For this study, 150 soil samples (distributed and undistributed) were collected from five provinces of Iran. Soil water retention was measured at 12 suctions and the compaction curve was obtained using uniaxial apparatus in the confined sample. In this research, 6 levels of estimators including compaction characteristics and equations coefficients were used to estimate water content. In general, results showed that the use of compaction curve was useful to estimate the soil water retention curve. The second and sixth levels with the estimators of Pc-Cc-Cs and parameters of stress-strain model (indirectly), respectively along with basic soil properties had higher estimation accuracy compared to other estimator levels. The reason for the excellence of these estimators can be due to their correlation with van Genuchten model parameters and mechanical concept of estimators. Moreover, the similarity between the two curves was one of the reasons for the appropriate estimation of soil water retention curve.

Recognition of soil water infiltration process is essential for improving irrigation efficiency, decreasing water losses and management of surface runoff. The aim of this research was to evaluate temporal variation of the Kostiakove-Louise infiltration coefficient parameters during a corn growing season. In this research, 16 irrigation events for 8 large scale furrow experiments were analyzed by the volume balance method for evaluating the Kostiakove-Louise infiltration parameters. The length of the experimental furrows used for this study were 120 meters. The results indicated that temporal variation of the Kostiakove-Lewise parameters during the growing season were not meaningful and possible error was less than 5%.

The groundwater level dropping has many problems. One of the most important problems is saline groundwater advancing in the upper area of the plains. Also, decreasing of saline effluent from the groundwater is another problem that occurs. The interceptor drain is a method for solving these problems. In this study, effect of Qazvin marshland interceptor drain is simulated. To monitor the effectiveness of these drains, wells of 99 loops were excavated in 9 sections perpendicular to the drain (A to I). Seven wells per section were excavated in the upstream at 10, 25, 50, 100, 250, 500 and 1000 meters distances from the drain and 4 wells in the downstream at 10, 25, 50 and 250 m. The wells water level was measured in once a month and a water sample was taken from each. Chemical analysis of the samples, and chemical changes in ground water drainage were determined. The condition of affected by drainage was simulated using the software package Geostudio. Model, the hydraulic conditions (model Seep/ w) is the model. The numerical model used in section B was calibrated using observations of August 2010 and the data were collected four months after it was verified. In the calibration phase, Values of modeling efficiency and coefficient of determination were 0.91 and 0.97, respectively. These values were 0.87 and 0.91 in validation phase, respectively. These values of validation show the good efficiency of the model in groundwater level prediction.

Artificial recharge of groundwater plays a pivotal role in the sustainable management of these resources. Sarkhoon plain in Hormozgan was carried out using geographic information system and combining it with the Shannon entropy and a pair-wise comparison test. For this purpose, 9 affecting elements of, water quality, water depth, permeability coefficient, thickness of alluvium, land use, transfer capability, land morphology and drainage density were selected and prepared. Then using entropy method and pair-wise comparisons, the weight of each standard and the classes of each layer were calculated. Next, the areas with constraint for flood spreading are removed and finally the entire area was divided and zoned into four classes using GIS analytical functions and Jencks algorithm. Results showed that drainage density factor weighing 0.211 is the most important factor for locating flood spreading in Sorkhun plain. Areas suited for flood spreading are frequently located at the morphological units of alluvial fan in the north part of the plain, with slopes of less than three percent, and allocated approximately 17.70% of the plain. Evaluate the results by comparing the successful implementation projects in the region was 78 percent overlap model can lead to weight each criterion in considering the impact of the uncertainty, Which can enhance the accuracy of the model output.

Biochar has received great attention recently due to its potential to improve soil productivity and immobilize contaminants and is proper as a way of carbon sequestration in soil. In this study, biochar produced from cow manure by slow pyrolysis at different temperatures (300, 400, 500, 600, 700 ◦C) and their physicochemical properties were analysed. Experiments were conducted to examine the effect of pyrolysis temperature on the cow manure biochar and to identify the optimal pyrolysis temperature for converting cow manure to biochar with agricultural usage. The results showed that with an incremental increase in temperature from 300 to700 ◦C, biochar yield, total N content, and organic carbon (OC) decreased, while pH, EC, ash content, and OC stability increased. The yield and stable OC of biochar was observed between 22.14 to 44.36 % and 35.63 to 72.36 % respectively. To produce cow manure biochar of proper for agricultural applications and a carbon sequestration, temperatures 400 and 500 ◦C are recommended respectively.

Parts of the Plain are different roles as pollutants velocity and reach into groundwater. Land assessment and their proper management for a variety of land uses, due to their susceptibility to transfer contaminations is essential. DRASTIC method as overlaying way has the seven influencing parameters for contamination susceptibility mapping. Due to local effects on DRASTIC model parameters, coefficients modify for the input data is required. . According to multiple studies in the Hashtgerd plain, to assess the aquifer vulnerability, modified DRASTIC method, logistic regression-DRASTIC and hierarchical analysis process DRASTIC was used. In addition to the DRASTIC input parameters, land uses were used in analysis considering its role in the production of contamination. The western part of the study area, there is an aquifer that charged from the eastern of the plain. DRASTIC model as output of the model validate with nitrates and eastern areas was excluded. In validating indicators of vulnerability, Spearman correlation, are calculated respectively 0.79, 0.84, 0.86 and 0.91 for DRASTIC, modified DRASTIC, logistic regression-DRASTIC and hierarchical analysis process –DRASTIC and Analytical Hierarchy Process has the highest correlation coefficient.

In arid and semi-arid regions in addition to water quality, water quantity also limits agricultural production development. In this situation, plant is put under simultaneous water and salinity stress conditions. Modeling agronomical plant response to simultaneous water and salinity stress can help operation management of the country's limited water resources. The objective of this study was to model agronomical plant response to simultaneous water and salinity stress. To do so, first the important water uptake reduction functions are investigated using basil greenhouse data. The results of these investigations indicated that there are no relationships between matric potential at readily available water (h3) and osmotic potential in any mathematical models. In this paper, a new mathematical model for investigating agronomical plant response to simultaneous water and salinity stress is given by modifying conceptual model of Homaee et al., at h3 arm (branch). The results of evaluating this new model using basil observed data, indicated that model is able to simulate plant response to salinity stress, water stress, and simultaneous water and salinity stress very accurately (RMSE=8.5% and R2=0.97).

Check dams have been widely used in erosion control projects of upland areas especially in arid and semi arid regions. These structures control and reduce the amount of sediments entering main rivers by trapping the sediment load of floods. Trapped sediments by check dam systems reduce the slope of gully and provide ideal condition to starting biological measures of erosion control such as vegetation cover establishment. Physical and chemical properties of check dam sediments have major role in determining the different aspects of their behavior like water holding capacity, water infiltration rate, and controlling nutrient loss and pollutants transportation. This study aims to analyze physicochemical properties of sediments in some successive check dam systems. The study was carried out in four seasonal waterways from two different region of Urmia city, northwestern Iran. Results indicated that the average sand content of the sediments in waterways lies between 54.4 and 88.4 percent. Sediments samples with sandy and loamy sand texture were coarser than the original soils of the adjacent hillslopes. Sediments were poor in macronutrients in comparison with original soils and the enrichment ratio of the N, P, and K were 0.53, 0.66 and 0.60 respectively. In the partially filled check dam systems, as a result of selective sediment deposition, sediment characteristics change regularly and the amount of clay and macro nutrients were higher in the downstream dams than the upstream dams. Results indicated that the check dam systems are not able to trap all sediment sizes and the great amounts of particles smaller than 2 micrometer in diameter, passed through the system in the form of suspended load. Principle component analysis of sediment properties strongly suggested the importance of macronutrients with sand and silt content in characterization of sediment properties.

In many of agricultural land water table is raised because of seepage from canal and surface recharge. This raised is gradually caused some problem appear in land such as waterlogging and salinity, ultimately leading to land degradation. Therefore development of agriculture and economics in that region are endangered. It is necessary before problems appear engineers and researchers consider the variation of the groundwater table.In this article that problem has selected which shows an aquifer lied on a slopping impervious barrier which is discharged by a constant discharge from the surface and two canals with (L) horizontal distance. The initial water table is located horizontally h0 above the either horizontal or slopping bottom. After recharge and canal commencement, water table starts to rise. The rate of rising depends on the rate and duration of recharge and seepage from canal.
In this article, application of DQM in discretization of governing equations for chosen case study and formulation of the problem is presented. For further comparison and find more reliable answer are used three method for discretization of governing equation:1-Explicit Scheme,2-Implicit Scheme,3-Semi Implicit Crank Nicholson Scheme.
This investigation confirm that DQM has vast capability and simplicity to produce accurate results which is satisfactory compatible with Finite Difference numerical model as well as whit analytical solution while is highly efficient in time and low cost of running. The discretization scheme in this method does not establish large sets of simultaneous equation to be solved and is not sensitive to the number of grids in its mesh. There for with a very small number of grids comparing to a very large number of required grids in Finite Difference scheme produce very accurate results close to analytical solution results and create exactly the same results as Finite Difference scheme produce.

Increasing trend of greenhouse gasses in recent decades has affected weather and climatic zones across the globe. The aim of this study is to investigate the effect of climate change on climatic classes of Golestan province, Iran based on the extended de-Martone index. Rainfall data of 60 rain gauges and daily minimum/ maximum temperature data of 22 weather stations during period of 1982-2010 were used as baseline observations. Besides, HadCM3 model outputs were statistically downscaled using LARS-WG model under A1B ,A2 æB1scenarios to project rainfall and temperature data for three periods of 2011-2040,2041-2070 and 2071 to 2100.Generated time series of mean annual rainfall, mean temperature and minimum temperature of coldest month of the year were interpolated using Kriging method. Based on extended de-Martonne index, climatic zones were worked out and drawn using GIS tools. Results indicated that Kriging method interpolated rainfall data with less error comparing to other methods. According to the results both temperature and rainfall in the region would increase but the increase magnitude may vary in different periods, such that in near future (2011-20140) the rate of rainfall increase would be more than temperature which lead to more humid climates. This will be reverse during 2071-2100 in which drier years are expected. Among the chose scenarios, the A2 projects the worse conditions for the study region. Taking into account the temperature gradient, the Geographically Weighted Regression method is suitable for regionalization of temperature. Comparative examination of climatic zones of province under climate change scenarios showed that warm semi-arid climatic class which does not exist at present, would cover about 5 % of the province. in the last study period.i.e.2071-2100 under A2 scenario.

This study aimed to investigate the effect of arsenic and phosphorus bioavailability of soil phosphorus and total phosphorus concentration in soybean for this purpose a factorial experiment in a completely randomized design with 3 factors and 3 replicates was conducted into the pots with soil media in the greenhouse of Agricultural Research. The factors were soybean with two levels (L17 native varieties and promising lines), arsenic with four levels (0, 10, 50 and 100 mg.kg-1) and phosphorus with four levels (0, 25, 50 and 100 mg.kg-1). Di potassium hydrogen phosphate and disodium hydrogen arsenate salts of phosphorus and arsenic in soil added. The results showed that by increasing in the concentration of arsenic in the phosphorus treatment, phosphorus bioavailability of soil increased (P≤0.05). 10 mg.kg-1 Arsenic in soil germination percentage increased to 6.4% compared to control (P≥0.05). High levels of arsenic (50 and 100 mg.kg-1) caused decrease (16.11 and 76.68 %, respectively) in the germination percentage in comparison to the control (P≤0.01). Adverse effects of concentrations of arsenic, which stop the growth and eventually death of the plant. Arsenic reduced shoot biomass and increased total phosphorus plant (P≤0.01). The results of interaction of phosphorus and arsenic showed that with increasing concentration of phosphorus in soil containing arsenic, total phosphorus concentration rose plant (P≤0.05).

Groundwater monitoring plays a significant role in groundwater management to control aquifer behavior. Thus, a groundwater monitoring network is required to control spatial and temporal fluctuations of groundwater characteristics. This study describes a new optimization method to design an optimum groundwater-level monitoring network and was implemented on Eshtehard aquifer. Database of the study was provided by kriging interpolation. Optimization of groundwater monitoring network was implemented by Non-Dominated Sorting Genetic Algorithm II (NSGA-II) with two objective functions of minimizing the root mean square error (RMSE) and minimizing the number of network wells which representing the cost of constructing, maintenance service and collecting data. Inverse Distance Weighting (IDW) was used to compute the groundwater-level in simulation part of optimization. The result of the study is a Pareto front showing the number of wells and corresponding RMSE which would be a guideline for groundwater monitoring network design. By selecting the required accuracy of the monitoring network data, the number of observation wells and their locations in the study area would be demonstrated.

In this paper, subsurface water profiles through coarse porous medium are investigated ýnumerically and then are compared with experimental data. Numerical simulations have been ýconducted using SEEP/W model which is based on the finite element method. Laboratory model of ýthe porous medium has 6.4m length, 0.8m width and 1m height. Crushed materials were used as ýporous media. Modeling scenarios were conducted for different values of flow discharges and ýthree bed slopes of 0, 4 and 20.3 % and then flow profiles and discharges were computed and ýcompared with those provided form experimental. The results indicated that application of ýSEEP/W model for simulating flow properties through coarse materials and rockfill structures do ýnot always present satisfactory outputs, wherein in most cases specifically in low slopes ýunderestimated subsurface water profiles ( seepage line) compared to observed profiles. Also ýcomputed flow discharge give a different behavior depend on bed slope and kind of materials. The ýresults of numerical model showed a good agreement in steep slope comparing to low slopes. ý

By using regionalization methods information from gauged sites transform to desired site. Up until now a variety of regionalization approaches have been proposed. In every site it is necessary to evaluate these methods and select the best method. It is of interest to understand how spatial weighted least square regression method based on depth function flood quantiles (SWLSR) compare with multivariate regression (MR) and Physiographical space-based kriging (PSK) methods. In each iteration desired station regarded as ungauged site then using genetic algorithm depth functions weights were optimized, finally (regarding) by taking account similarity between desired site and others sites flood quantiles corresponding to different return periods were estimated. By means of a leave-one-out cross-validation procedure, the performance of SWLSR was compared to MR and PSK methods for prediction of 10, 50 and 100 yr for 26 gauging station in the Southern Alborz. . The Result showed SWLSR approach yielded lower root-mean-square estimation errors and higher Nush Sutcliffe criteria thaneither the MR or the PSK approaches. PSK method estimated foold discharge in ungaged basin better than MR. In depth based approach Nush Sutcliffe criteria values for flood quintiles (Nash–Sutcliffe efficiency values for 10,50 and 100 yr floods were 0.64, 0.65 and 0.65 respectivly) three corresponding to different return periods were similar.In this method relative error to area in small catchment were biger than those obtained in big catchment.

The objectives of this study were to compare the capability of ammonium acetate (NH4OAc) and sodium tetraphenylborate (NaBPh4) in the release of potassium from micaceous minerals including biotite, phlogopite and muscovite. Non-linear regression of pseudo second-order, power function, Elovich and parabolic diffusion equations models inspected to describe potassium release from those minerals in a period of 5 to 11520 minute. The results indicated that the amount of NaBPh4-extractable K was s higher than NH4OAc-extractable K. NaBPh4 extractant released 56.15, 60.14 and 10.78% of total potassium from phlogopite, biotite and muscovite respectively, while those values were 0.81, 0.84 and 0.62% for NH4OAc extractant. The results also showed that the potassium released from minerals in two different phases. The rapid phase occurred at the beginning of experiment and the second phase with lower rate release happened until to the end of experiment. Parabolic diffusion and exponential function equations reasonability described the potassium release from micaceous minerals very well according to R2 and SE indexes. Kinetics of potassium release from biotite and phlogopite minerals were described very well by power function equation (R2=0.98-0.99 and SE=1.20-2.43). The best-fitted kinetic models for the phlogopite (R2=0.98 and SE=2.23) and muscovite (R2=0.87 and SE=1.26) minerals were Elovich and parabolic diffusion equations respectively. Therefore, it may be concluded that the release of potassium is controlled by diffusion process from the surface of the studied minerals.

Increasing demand on water resources has led to the challenges related to increased water stress and exacerbate conflicts, disputes and lack of collaboration between the various stakeholders there. The social evaluation of local beneficiaries according to the method network analysis to identify the challenges and opportunities that advance planning and sustainable management of water resources is required. The social capital of local beneficiaries using social network analysis approach is examined in Sarab-e Shah Hossein Village of the Razin watershed located in Kermanshah province. The results indicate a high level of social capital based on trust and Participation relations and cohesion and stability of the network is very strong in against of tensions and crises are evaluated. Also the high degree of unity and Solidarity among the people will cause cost and time of implementation of cooperative water resources to be reduced. It can be argued that, based on high levels of trust, collaboration, cohesion and social capital among the people of the village, a successful water resources co-management is expected to be operating. Moreover, successful water resources in the local level is impossible without the social monitoring of stakeholders and this method is effective in achieving successful water resources co-management at the local level.

In order to evaluate the performance of subsurface drainage, a study at physical model scale in condition of second crop paddy fields was done. In the physical model, drains were installed in two depths 40 (D40) and 60 (D60) cm at two separate boxes and triticale was cultivated after rice harvest. In the time of rain, drainage sample parameters include EC, SAR, pH and TSS were measured in the laboratory. The water table was read by piezometer. The results showed that with increase in drainage depth, EC was increase and SAR value declined. Trend of EC was decreasing throughout the experiment, so that EC value at the end of experiment period for two drainages D40 and D60 decreased with a rate of 53% and 8% compared to the start of period. TSS values and trend throughout the experiment demonstrates the use of geotextile at the roles of its cover. It was found that the drainage installed at a depth of 40 cm can be more successful in the control of soil drainage and prevent waterlogging.

Wind erosion is one of the main factors in soil and environment degradations and air pollution in arid and semi-arid areas. Existing methods of soil erosion control, including oil and chemical soil stabilizers, are too costly and they introduce toxic materials into the soil with significant environmental impact. Therefore, this research was conducted to determine the effectiveness of microbial induced calcite precipitation (MICP) as a biological and environmentally friendly method to improve the erosion resistance of loose sand dunes. For this purpose, the erosion of biocemented soil samples was measured experimentally in a wind tunnel under the wind velocities ranging from 10 to 55 kmh-1at a height of 10 cm above the tunnel floor. Results demonstrated that the weight loss of MICP-treated samples relative to the weight loss of control treatment was significantly decreased at all velocities. The effect of biological treatment on wind erosion control was even superior at the higher velocities. Erosion rate of MICP-treated samples was 2.13 against 240 kgm-2h-1 at the velocity of 55 km.h-1. The penetration resistance of the MICP-treated soil samples was observed up to three times higher than from control treatment, indicating a significant improvement of surface resistance in biologically treated samples. The result of SEM and XRD analysis shows that CaCO3 was mainly precipitated as vaterite crystals forming point-to-point contacts between the sand particles and improving surface resistance against wind shear velocity.

In this work, remediation of a contaminated clay soil with gasoline was studied through experimental tests by thermal and washing methods. A natural clay soil was contaminated artificially by different percent of (5% and 10%) gasoline. The contaminated soil was remitted at different temperatures (50, 100 and 1500 C). In addition, washing method was conducted on contaminated samples by using two kinds of surfactants (SDS and Tween 80). Experimental tests were including gradation, Atterberg limits, compaction and uniaxial compression tests which were performed on samples of natural, contaminated and remediation soil. Experimental results showed that adding gasoline to natural soil cause changes in physical and mechanical properties of soil and these changes are functions of gasoline percent. The results also showed that both thermal and washing techniques are effective in remediation of soil particularly for soil contaminated with 5% gasoline but the effect of them, and particularly surfactants, is reduced by increasing the percent of gasoline.

This research was conducted to evaluation of extraction methods for determining the available iron (Fe) and active Fe in corn plant (Zea mays L.) at 21 calcareous surface soil samples in the East Azerbaijan province. In a greenhouse experiment, corn plant single cross 704 cultivar has been cultivated with 3 replications. After 60 days, the plant growth parameters were measured. According to the results, DTPA and AB-DTPA had the highest linear correlation coefficient with growth indices of corn such as active Fe concentration, chlorophyll index, Fe content, fresh weight and shoot dry weight as well as with some physical and chemical properties of soils. AB-DTPA due to a correlation coefficient greater than DTPA and simultaneous extraction of multiple nutrients was chosen as the best extractant. On the average, rapid ammonium oxalate and AC-EDTA extracted the maximum and minimum amounts of Fe, respectively. The both of 1.5% o-phenanthroline and 1N HCl methods were suitable for measuring corn active Fe concentration. Significant correlation (r=0.66 ,p