مجله تحقیقات آب و خاک ایران
سال چهل و هشتم شماره 3 (پیاپی 30، مهر و آبان 1396)

In this study, to evaluate the efficiency and effectiveness parameters about rainfall-runoff relations , SWAT models have been used inTalar watershed of Mazandaran province .By using of this model ,has done ,calibration based on 8 rainfall station with daily precipitation, 5 evaporation station with daily temperature along output discharge in shirgah-Talar hydrometric station.Performing the calibration and validation of this model , was simulated initially based on 21 parameters with high sensitivity . In validation phase of 21 selected parameters, study about p-value and t-state indices shows sensitivity and behavior of parameters .At this stage, CN2-MGT parameter with the least amount of p-Value index and the highest index value t-State is recognized as the most sensitive parameters .The first phase of model calibration results showed that weaknesses in the simulation model that is well coefficients p-factor, r-factor, R2 and NS respectively 0.04, 3/91 , 0/01, -44/15.Due to these issues by analyzing the results of the first phase of this study, we calibrated 8 sensitive parameters through the first 21 parameters until created better correlation between simulated and observed discharges. In validation stage of 8 sensitive parameters in 95% confidence interval, created high correlation between simulated and observed discharges and shows in the result of scatter plots of this phase . Comparison of p-factor,r-factor,R2,N.S with 0.93, 0.93 ,0.79 ,0.98 respectively shows the better model simulation that cause efficiency of model for simulation in this stage.

Most of hydrological phenomena have a stochastic and probabilistic nature and the relationship governing on these phenomena are almost unknown and ambiguous. Therefore, the theories of statistic and probability apply for describing and forecasting of such phenomena. One of the hydrological phenomena which have a complicated nature and causes too much damage is the flood. In the present study, flood frequency analysis in the Dez basin at the junction of two hydrometric stations of Sepid Dasht Sezar (SDS) and Sepid Dasht Zaz (SDZ) was performed during the period of 1957-2012 using the copula functions. The copula is a function which joint the univariate marginal distribution to form a bivariate or multivariate distribution function. For this purpose, first the partial series of flood at studied stations were extracted using the Malmoud-Tookart method. In the next step, 11 different distribution functions were fitted on the extracted flood series and the Generalized Logistic (SDS station) and Generalized Extreme Value (SDZ station) distribution functions were selected as the best fitted ones. After selecting the suitable marginal distributions, some of Archimedean copula functions (Ali - Mikhail – Haq, Frank and Clayton) were used for joint flood frequency analysis in Dez basin. Results showed that the Frank copula had the highest match with empirical copula for paired flood data of SDS and SDZ stations. For investigating the return period of events the joint return periods in two states “AND” and “OR” and also the conditional return period were considered. Based on the results obtained from joint analysis of flood series in two river branches, it was found that the severe flood events may occur simultaneously at SDS and SDZ River branches every 70 years.

Regarding the importance of efficient use of agricultural water, management and distribution of water in irrigation networks are necessary to increase efficiency. Monitoring and evaluation of water management and distribution methods should be done continuously, to criticize and improve these procedures. For this purpose, some standard and effective methods have been developed by international organizations. In this study, water distribution in Qazvin irrigation network and its external factors were considered using the rapid appraisal process (RAP). The results showed that the water resources usage in the region is not purposeful and there was no plan to exploit the water resources in the network. In this period, responsible governors distributed only about 28 percent of total available water in the year. It has been the major cause of water losses. It was also found that the temporal water distribution is not properly done in the canals and in the most months of the year the amount of distributed water is less or more than required water for crop pattern. This indicates that water losses in the network had been due to lack of information, poor infrastructure or to compensate a part of conveyance losses. The total surplus of distributed water in the network in the year 2013, have been about 56 million cubic meters, which is 25 percent of total required water for cultivated crops.

Sharp-crested weirs are common measuring devices in rivers and irrigation networks. Their installation and operation are simple yet very practical. The hydraulic performance of sharp-crested weirs and their head-discharge equations in unsteady flow condition are of great interest, however, very limited studies are available in the literature. In the present study, the hydraulic performance of 90° V-notch weir, located at the end of a storage, was investigated in unsteady flow condition and the differences between steady and unsteady overflow were observed and evaluated. The results indicate that the difference between steady and unsteady discharges are significant whereas the difference value of investigated scenarios arise up to 40 percent, sometimes. Therefore, the previous head-discharge equations are no longer valid.

Recently, due to improvements and progresses in nanotechnology, application of Nano particles in different sciences especially geotechnical engineering have been widely considered. In this research, the effect of different amounts of Nano clay on dispersivity potential of two clayey soils with low and high plasticity has been studied. For this purpose, first identification tests were implemented on clayey soils and Nano clay and then pinhole tests conducted on specimens of soils with different amounts of Nano clay particles including ; 0, 0.25, 0.5, 1, 2 and 4 percent by weight for evaluation of their dispersivity potential. The specimens were cured for 1, 3 and 7 days. The results indicated that that the addition of Nano clay particles could reduce dispersive potential of clayey soil considerably. It is also found that the effect of Nano particles on two clayey soils with different plasticity is the same and the plasticity characteristics have no important role in chemical reaction between Nano clay particles and clay minerals. Furthermore, curing time was found to be as a main factor in stabilization of clayey soils with Nano particles.

Sprinkler systems should have been implemented to assess the success of the system can be determined and Practical solutions to improve the efficiency of irrigation systems and provided suggestions for future systems. The aim of this study has been to evaluate the uniformity of water distribution and manure in the field under centerpivot sprinkler irrigation system. The place of this research was in the field of Tehran University in Karaj and in the years of 2015 and 2016. Nitrogen in use by crop has been from fertilizer source of urea (46%). Centerpivot irrigation system to measure the distribution uniformity, measure the amount of water and nitrogen had collected in cans which had arranged radially. Uniformity coefficient of Heermann and Hein in the cans in the first and second measurements were 84% and 91%. Uniformity coefficient of fertilizer distribution was in the first and second year fertigation, respectively 69% and 72%. The results has shown the uniformity coefficient from fertilizer distribution uniformity coefficient is less than water distribution uniformity coefficient .

Shallow saline water table and reducing the quality and quantity of freshwater, is important issues of soil and water problems in some of the important the plains of. Therefore groundwater contribution to crop water use may be useful. The objectives of this study were finding the model of groundwater contribution to supply water needs of palm seedling. To obtain this goal, the experiments was performed in three replicated split-split–plot designs inclusive of 3 levels of groundwater salinity (

In order to investigate the effect of the amount of water in subsurface drip irrigation on water use efficiency, performance dates, yield components, and determine the best irrigation in two varieties of palm, a split plot experiment in a randomized complete block design with three replications for the second year experiment (2014-2015) was carried out in Behbahan agricultural Research Station. The main factor was the amount of water in subsurface drip irrigation at three levels based on 75%, 100% and 125% water requirement and sub-plots, the two Variety of Kabkab and Zahedi. in all quantitative traits except water use efficiency such as berry weight and the core, length, number of berries per cluster, date yield and water use efficiency, water levels, there were significant differences between treatments. As 2582.1 cubic meters per hectare consumption of water in the treatment of 75% water requirement in addition to saving water consumption by as much as 28.8 and 45.5 percent compared to 100 and 125% water requirement, The yield of the Treatment Research 6563.6 kg and water use efficiency was calculated as 2.542 kilograms per cubic meter. Two varieties of palm Kabkab and Zahedi also not significantly different in terms of yield and water use efficiency. So that in the hearts 6134.9 kg per hectare yield and water use efficiency was calculated 1.721 kilograms per cubic meter.

High volume of drained water and low quality are two major challenges of subsurface drainage systems’ operators. Dry Drainage (DD) can solve these problems with low cost and environmental considerations where the irrigation water is much less than the amount to satisfy the extent of the available land. Results of previous studies showed that by DD, we can control salinity of root zone with leave half of land. In this study, ratio of cultivated strip width to uncultivated strip width was investigated as a major effective parameter on DD efficiency. This study was conducted with two lysimeters at research field located in University of Teharn, Abouraihan College on 2015, by considering of two different ratios of cultivated strip width to uncultivated strip width (1:1 and 2:1). Sport grass was used in cultivated strip as reference crop. Soil texture was Loam and irrigation water salinity was 3 dS/m. Irrigation water was produced by mixing of tap water and saline water of Qazvin’s Marshland. Results showed that, salt balance in root zone can be maintained by increasing amount of cultivated strip width. Though ratio of 2:1 will be accepted but we should consider that by increasing this ratio, amount of accumulated salt at uncultivated strip will be increased, therefore we need better management to remove salt in this condition. Also results of each lysimeters showed independently that, Dry Drainage has ability of transporting salt from cultivated areas to uncultivated areas and after a while, root zone salt concentration will be balanced. Soil salinity of cultivated strip did not exceed 6 dS/m at end of test; nearly twice the salinity of the irrigation water.

The visible and near-infrared (VIS-NIR) spectroscopy are non-destructive, rapid, cost-effective techniques, with minimal samples preparation and no loss or damage to the environment that could be alternatives to conventional soil analysis methods. The objective of this study was to evaluate the ability of VIS-NIR spectroscopy to predict some soil properties of Qorveh and Dehgolan plains, Kurdistan Province. For this propose, 120 soil samples were collected from the study area. Soil properties were measured by standard laboratory methods. The soils spectral reflectance over 350 to 2500 nm range were measured using a handheld spectrometer apparatus. Different pre-processing techniques were evaluated after recording the spectra. Stepwise multiple linear regression (SMLR) was used to estimate some soil properties. According to RPD values, statistically percision predictions were obtained for cation exchange capacity (2.02), and estimations for clay (1.7), silt (1.59), sand (1.8), geometric mean particle diameter (1.52) and geometric particle-size standard deviations (1.66), bulk density (1.53), particle density (1.55), organic carbon (1.74) and calcium carbonate equivale (1.49) were acceptable.

The visible and near-infrared (VIS-NIR) spectroscopy are non-destructive, rapid, cost-effective techniques, with minimal samples preparation and no loss or damage to the environment that could be alternatives to conventional soil analysis methods. The objective of this study was to evaluate the ability of VIS-NIR spectroscopy to predict some soil properties of Qorveh and Dehgolan plains, Kurdistan Province. For this propose, 120 soil samples were collected from the study area. Soil properties were measured by standard laboratory methods. The soils spectral reflectance over 350 to 2500 nm range were measured using a handheld spectrometer apparatus. Different pre-processing techniques were evaluated after recording the spectra. Stepwise multiple linear regression (SMLR) was used to estimate some soil properties. According to RPD values, statistically percision predictions were obtained for cation exchange capacity (2.02), and estimations for clay (1.7), silt (1.59), sand (1.8), geometric mean particle diameter (1.52) and geometric particle-size standard deviations (1.66), bulk density (1.53), particle density (1.55), organic carbon (1.74) and calcium carbonate equivale (1.49) were acceptable.

The present study aims to analyze the accuracy of four global gridded precipitation datasets namely CRU, GPCC, PCDR, DEL over Lake Urmia basin, Iran. To this end, observed data have been collected from six synoptic stations namely Urmia, Mahabad, Takab, Tabriz, Maragheh and Saqqez over a period of 30 years (1984-2013). Evaluation was done based on Nash-Sutcliffe Efficiency (NSE), correlation coefficient (CC), Root Mean Square Error (RMSE) and Bias. Results on all scales (monthly, seasonal and annual) showed the proper performance of the GPCC. For example, in annual scale, GPCC, outperformed other databases with NSE, CC and RMSE values of 0.87, 0.94, and 31.12 mm respectively. According to the results, performance of the CRU is acceptable. This dataset has been performed better than the GPCC, based on Bias. Also PCDR''s and DEL''s performance were unacceptable in all time scales.

Selectivity coefficients and thermodynamic parameters of K-Ca exchange in a clay separated from a soil with dominant illite (mica) mineralogy were studied at two different ionic strengths (0.3 and 0.002 M). The clay was depleted for periods of 0, 6, 25 and 150 hours. The values of the Kerr (KKer), the Vanselow (KV), the Gapon (KG), the Gaines-Thomas (KGT) and the Davies (KD) selectivity coefficients were increased with K saturation. In the range of EK≤0.7, KV was smaller than 1, suggested that the exchangers preferred K over Ca2 in this range, however at high EK values, Ca2 was preferentially selected. Rothmund-Kornfeld model was fitted well to exchange data. β in this equation was smaller than 0.66, demonstrating heterogeneity of exchange sites in the clays. The value of β decreased with K-depletion. Furthermore, β decreased with reduction in ionic strength from 0.3 to 0.002 M, indicating an increase in surface sites heterogeneity. Regular solution (RS) model was also well fitted to the data. Thermodynamic equilibrium constants (Kex) were smaller than 1 and the standard free energy of the exchange reactions (ΔG°ex) were positive in all clays. The values of Kex in different K-depleted clays were not significantly different, indicating that the depletion-collapse cycle of these illitic clays did not change their selectivity for K or Ca2. The decrease in the ionic strength led to the increase in Kex and decrease in ΔG°ex, an indication of reduced tendency of clay for K relative to Ca2. With increasing EK, Kex remained relatively constant. ƒK increased with ECa and ƒCa decreased. Comparison of ƒK and ƒCa calculated by the thermodynamic method and the regular solution model indicated that the values of ƒK in RS model were greater than of thermodynamic method.

A robust method for parameter estimation is required in determining the governing model in kinetic and equilibrium sorption modeling. In nonlinear method, parameters are estimated using a trial and error procedure to minimize an error function. In this study the effect of different error functions on estimated parameters of kinetic models (Pseudo First and second order) and equilibrium models (Langmuir and Freundlich) were examined. Best error function was determined using 239 series of kinetic data and 129 series of equilibrium data which are extracted from 100 previous studies. Using various error functions shows a lot of changes in estimated parameters, so that the largest changes for parameters is about 100%. using normalized error method based on experimental data, best error functions respectively are Errsq, Hybrd and Mpsd with average normal error of 3 and 3.4 and 3.6. Ef and Crm methods have the maximum normalized error according to the experimental data.

Cyanobacteria are a unique group of photoautotrophic bacteria that some of them due to their structural characteristics show a significant tolerance to salinity. These organisms play an important role in terrestrial environments, especially in arid and semi-arid region. In this study, soil cyanobacteria were isolated from the desert regions of Iran and then isolates resistant to hypersaline conditions identified. 40 soil samples were collected from the Kavir National Park. Samples were separated after culture in BG11 and ASN III (3.5, 5, 6 and 7% of NaCl) mediums and incubated under appropriate conditions of temperature and light and identified initially using morphological keys and then by molecular methods. Out of 40 sampling sites cyanobacteria were isolated only from four hypersaline sites. Twenty-seven morphotypes were identified in medium without sodium chloride that five strains belonging to two genera were able to grow in the presence of 3.5% sodium chloride. Among the five strains, three strains in 5% and two strains in 6% of sodium chloride grew. Only Phormidium autumnale 61et was able to tolerate 7% sodium chloride that was isolated from the site with 87.80 dS/m. The results showed that some isolated cyanobacteria from soils of Kavir National Park can grow in extreme conditions such as salinity stress and create a biologically active mass.

In this study a factorial experiment in a completely randomized design performed in order to compare the kinetics of potassium (K) release from feldspar, illite and phlogopite in presence of microbial inoculation. The first factor involved microbial inoculation (bacteria, fungi and control), the second factor was K mineral types (feldspar, illite and phlogopite) and the third factor was incubation time (1, 2, 4, 8, 12, 16, 24, 32, 48, and 64 hours). The results showed that microbial inoculation caused an increase in potassium release and soluble-K (Ksol) which in samples inoculated with bacteria and fungi increased 92.3 and 92.8 percent in comparison to control, respectively. Mineral type showed significant impact on the kinetics of potassium release, potassium release from phlogopite was 1.11 and 1.13 times higher than feldspar and illite, respectively. The maximum reduction of pH and the highest increase of soluble-K, was observed in phlogopite treatment which was inoculated with fungi. pH amount in this treatment was decreased 2.69 unit and Ksol was increased 7.38 unit compared to the control. Among the kinetic models which were fitted, according to R2 and SEE, kinetics of potassium release was described with ellovich, power function, first order and parabolic diffusion equations satisfactorily. Among these four equations, the power function equation was detected as the best model for data fitting. Significantly inverse correlation (r = -0.83**) was observed between Ksol and pH. Therefore, the presence of silicate solubilizing microorganisms increase the rate of potassium release from K- bearing minerals.

Wind erosion is problem in recent years has affected many parts of the Iran. Due to the harmful effects of petroleum mulch, polymer and plant mulch is particular importance to reduce the environmental impact of these compounds and solve the problem of soil loss in erosion-prone land. In this study, two types of polymer and plant mulch as soil stabilizer were used in four levels 0, 15%, 30% and 60% on three types of soil from wind erosion sites in Khuzestan. Effect of mulch to reduce soil loss in the wind tunnel at speeds of 8, 10, 13 m/s were examined. The results of experiments were examined with SPSS software performed factorial experiment in a randomized complete block design and Duncan. Statistical analysis showed that the soil treated with both mulch, significantly different from the control soil to reduce soil loss. It also shows that between two types of mulch in terms of impact on the reduction of soil loss is not significant difference, But the mulches used in various concentrations are significantly different from the one percent level. Results Effect of polymer and plants mulch (both liquid) showed that the use of polymer mulch could well be Decrease the soil loss at speeds of 8, 10 and 13 m/s. Also, mulch plants, reduced the soil loss in the Agricultural soil Abdolkhan area and Hoveyzeh area. But in the land of sand Borvayeh area, this mulch, Had not a positive impact on reducing soil loss in low concentrations.

The purpose of this research was the determination the critical level of copper for corn in 21 soils of East Azerbaijan province. In a greenhouse experiment, corn plant (Zea mays L.) single cross 704 variety, cultivated in two levels of Cu, zero and 7.5 mg Cu kg-1 soil with three replications. After the 60 days (end of the growth period), before harvesting chlorophyll index of leaf were measured, then plant harvesting and wet and dry weight in shoot and copper content were measured. Critical level of soil Cu for corn with DTPA and AB-DTPA methods were measured by using plant response column order procedure, graphical Cate-Nelson, Cate-Nelson analysis of variance (ANOVA) and Mitscherlich-Bray. According to the results, by application of copper, significant increases in corn shoot dry weight, concentration and content of Cu occurred. Critical level of soil Cu for corn with DTPA method based on 90 % relative yield, was determined as 1.46, 1 and 1.70 (mg Cu kg-1 soil) by using plant response column order procedure, graphical Cate-Nelson, Cate-Nelson analysis of variance (ANOVA) and Mitscherlich-Bray, respectively and for AB-DTPA method was 1.50, 1.80 and 2.94 (mg Cu kg-1 soil), respectively. The Mitscherlich-Bray equation coefficients C for these methods were 0.5874 and 0.3397 kg soil mg-1 Cu, respectively. In this research, the Cate-Nelson analysis of variance method was not the appropriate for determination of critical level of Cu for corn. Drawing the plot by the Excel softwar and correlation coefficients with statistical analysis by using SPSS software was performed.

Estimation sediment load of rivers is the most important challenges in river engineering. So, it was addressed different models by varying structures to estimate sediment load. In this study, it was reviewed effectiveness of geo-morphometric parameters and data mining technique to predict suspended sediment load in 68 basins in two different regions of Iran. For this reason, it was run six artificial neural networks models, linear regression, K-nearest neighbor, Gaussian process, support vector machine evolutionary on two types of suspended sediment data (i.e. maximum and average sediment). To optimize models, it was used geo-morphometric parameters and river discharge as input data into model and it was used attribute reduction technique to decrease the algorithms space. Results of models evaluation indicated that models performance is difference in average and minimum sediment data, so that the best method to predict average sediment is the Gaussian model by correlation coefficient, 0.988 and root mean squared, 11.004 and the best method to predict minimum sediment is support vector machine evolutionary model by correlation coefficient, 0.966 and root mean squared, 0.171.

In order to evaluate using effluent (as sequential irrigation), a study was conducted at research farm at Shahid Chamran University of Ahvaz (located at latitude 31˚ 18’, longitude 48˚ 39’ and elevation 18m) during 2014-2015. Regarding to this purpose, a farm (with long 30m and width 24m) was selected and divided into 3 parts (A, B and C). Corn, soybean and sunflower were cultivated in parts A, B and C, respectively and effluent was used for irrigation of next parts. In part B, a split-plot design as randomized complete blocks with two treatments: irrigation type (Karun River and effluent) and urea fertilizer (100%, 75% and 50% application) was applied. Experiment design in part C was similar to part B except at 75% urea fertilizer. ANOVA results for soybean revealed that interaction between irrigation type and urea levels had significant effects on growth yield and biological water productivity (P