Iranian Journal of Soil and Water Research
Year:2019 | Volume:50 | Issue:2 |Papers Count:20

The objective of this study was to evaluate the effect of compost and biochar from trees pruning residues in the presence of plant growth promoting rhizobacteria (PGPR) on some biological properties of calcareous soil. The experiment was carried out in a completely randomized design under greenhouse condition in rhizobox. The factors included organic matter (biochar, compost and control), microbial inoculation (PGPR bacteria and no microbial inoculation as a control) and soil (rhizospheric and non-rhizospheric soil). The organic carbon, microbial biomass carbon, microbial biomass phosphorus, microbial respiration, substrateinduced respiration and phosphatase enzymes in the rhizospheric and non-rhizospheric soils were determined at the end of growth period. The results showed that the simultaneous application of organic matter and microbial inoculation increased soil biological indices significantly as compared to control treatment. Furthermore, the compost treatment increased the microbial biomass carbon, microbial biomass phosphorus, alkaline and acid phosphatase enzyme activity in the rhizospheric soil by 1. 02, 1. 14, 1. 16 and 1. 10 times, as compared to the ones in non-rhizospheric soil, respectively. However, the lowest fraction of microbial biomass carbon to microbial biomass phosphorus was observed in rhizospheric soil of compost treatment. Microbial respiration and substrate-induced respiration in the compust rhizospheric soil were measured to be 1. 04 and 1. 21 times higher than the ones in the non-rhizospheric soil, respectively. In general, application of organic matter in the conditions of microbial inoculation compared with non-microbial inoculation lead to improve soil biological properties.

In order to investigate the effect of different levels of nitrogen and nitrate: ammonium ratios on yield and oil percentage of Thyme daenensis in saline and non-saline conditions, a factorial experiment was conducted in a randomized complete block design (RCBD) with 30 treatments and three replicates in perlite and sand medium. Nitrogen at three levels (5, 10 and 15 mM), nitrate: ammonium ratio at five levels (100: 0, 75: 25, 50: 50, 25: 75, 0: 100) and salinity at two levels (0 and 50 mM sodium chloride) were applied. Results showed that the highest fresh and dry weight, percentage and yield of crop oil were obtained at 15 mM nitrogen and 75: 25 nitrates: ammonium ratio in the non-saline conditions. In the saline condition the fresh and dry weight, percentage and yield of crop oil were reduced in all treatments and the highest yield was obtained in 15 mM nitrogen and 50: 50 nitrates: ammonium ratio. Generally, it was concluded that the ratio of 75: 25 nitrate: ammonium in non-saline condition and the ratio of 50: 50 nitrate: ammonium in saline condition were the optimum ratios at 15 mM nitrogen level for obtaining the highest yield and oil percentages.

Shortage of water resources, development of drip irrigation (T-Tape) method in the arid and semi-arid regions, enhancement of Nano fertilizer application in agriculture, the effect of magnetic water on yield and water use efficiency for crops led to carry out a research for this purpose. Therefore, the present study investigates the possibility of increasing yield and water productivity of soybean crop using drip irrigation (TTape) with Ferro-iron fertilizer under magnetic and non-magnetic conditions in a complete randomized block design with three replications in the Kashmar city, East of Iran during 2016. Main treatments consisted of two types of magnetic (M1) and non-magnetic water (M2) and sub-treatments including four levels of Nano-iron fertilizer (0 or no fertilizer: N1; 0. 2: N2; 0. 4: N3 and 0. 6: N4 g/liter per unit area). The results showed that the effect of Nano-iron fertilizer and magnetized water on grain yield, biomass and water use efficiency were significant at 5% level. Although, the interaction effect of magnetic water and nano-iron fertilizer was not significant on crop properties. Irrigation with magnetized water and Nano-iron fertilizer at 0. 6 glit-1m-2 increased the grain yield (with the production of 3670 kg/ha) 25% as compared to the control treatment. The lowest grain yield was obtained in non-fertilizer and non-magnetic water treatment with the production of 2. 565 kg/ha. The water use efficiency of soybean was varied from 0. 49 to 0. 71 kg/m3, which were corresponded to M2N1 and M1N4 treatments, respectively.

Because of the significant impact of water on economic development, social stability and ecological balance, the allocation of water resources has become a worldwide issue. In this paper, a multi-objective planning model consist of two objective functions was developed for water allocation to maximize the productivity of economical benefit and the equity of water allocation in Sefidroud basin located in Iran. A Compromise Programming method was applied to trade off both the objective functions. The different weights of the objective functions and the definitions of TDS, DSA and DSB schemes were investigated in terms of equity, economical benefit productivity and equity establishment. The results showed that TDS is the best scheme for balancing the target functions. With the except of TDS, surface water allocation and economical benefit do not follow a particular pattern in other weights of target functions, so that decision makers are confused to choose the best weights of the objective functions. Shannon Entropy theory is a suitable solution for selecting the best weights of the objective functions. The results obtained by applying the Shannon Entropy theory showed that the best weights of the objective functions for the productivity of economical benefit and water allocation equity according to the decision maker’ s priority were 0. 35 and 0. 65, respectively. Generally, the results of this study showed that if decision maker’ s priorities were not clear, Shannon Entropy theory and Compromise Programming method could be used to determine the weights of each objective functions in order to make a balance among the objective functions.

Determining the onset, severity and duration of drought provides vital information for managing water resources to decision makers. The computation of these parameters requires integrated data on soil moisture content and groundwater level. The installation and utilization of a regular network system for recording these data in massive water basins is very costly. In the central plateau catchment of Iran where the average rainfall is very small, the required observational data with suitable spatial distribution are not available. In this paper, the frequency, duration and severity of agricultural droughts in this catchment are determined by the Total Storage Deficit Index (TSDI) obtained from the GRACE satellite based-data. Then, due to the heterogeneous distribution of meteorological stations in the studied area, 142 stations were selected and the MicroMet interpolation model and Kriging geostatistical method were used to fit a homogenous network on the meteorological data at the catchment area. Finally, the Standardized Precipitation Evapotranspiration Index (SPEI) was calculated with timescales of 3, 6 and 12 months to be compared with the results of TSDI. Based on these calculations, the studied area has experienced several agricultural droughts with different severity and extent that the spatio-temporal distribution and drought severity obtained from both indices are in good agreement with each other.

This study was carried out to calibrate and validate the WOFOST model for winter wheat in Qazvin plain. Firstly, the model was calibrated based on the phenological data obtained from the field experiment during the year 2016-2017. Then the model was validated based on the four years field data. After that the model recalibrated in terms of physiological aspects using leaf area index, biomass and crop yield. The model simulated flowering and maturity dates with 11 and 4 days accuracy (RMSE). The simulation results showed an acceptable fitness with the observation data. After calibration, the root mean square errors (NRMSE) of simulated model were estimated to be 12. 05, 11. 1 and 15. 4% for yield, biomass and leaf area index, respectively. Based on the obtained results, the model was estimated all the proposed parameters less than the field data (CRM<0). The highest model efficiency was obtained for leaf area index. After that the model efficiencies were 0. 95 and 0. 94 for crop yield and biomass, respectively. The lowest value for determination coefficient (CD) was obtained for biomass, showing the largest dispersion between simulation and measurements values.

Salt accumulation in the soil profile is a challenge for irrigated agriculture and the study of salt concentration and its variation in the soil profile under different irrigation systems and management is needed. In this study, Sodium, magnesium, calcium and SAR concentration were studied under three irrigation regimes; farmer management (I1), Irrigation requirement (I2) and I2 plus leaching requirement (I3) in Safaeyeh in Kerman during two cultivation years (1391-1392). According to the results sodium, magnesium, and SAR deceased after irrigation but calcium did not affect by irrigation time. In development growth period, the highest values of SAR, sodium and magnesium were found to be corresponded to 75, 50 and 75 cm soil depth, respectively. The highest values of sodium and magnesium in I3 treatment were 123. 4 and 43. 6 meq/lit which were corresponded to the soil depth of 75cm. The highest value of calcium in I3 treatment was correspond to the soil depth of 25cm which was 52meq/lit. The highest value of SAR (12. 4) was belong to the soil depth of 75 cm which indicates calcium has moved upward and toward the emitter. The interaction effect of irrigation regimes, soil depth, and recording time (before and after irrigation) showed that the highest concentrations of sodium, magnesium and SAR were 131. 8, 74. 4 and 54. 3 meq/lit respectively, which were belong to I3 and 75 cm soil depth before irrigation. The highest amount of SAR was 12. 8 which were belonging to I3 treatment, too. Calcium variations in the soil under I2 and I3 irrigation regimes shows the important of irrigation management for salinity control. The results showed that I2 have better performance than the other irrigation regimes due to less salt accumulation and SAR values in the root zone.

Evapotranspiration is one of the most important processes in water and radiative transfer in hydrological cycle, and the required energy for this process is provided by solar radiation. Therefore, the accuracy of evapotranspiration estimation is strongly depends on the accuracy of solar radiation estimation. This study was conducted to evaluate the different surface solar radiation models such as empirical models (Angstrom and Hargreaves-Samani), physically-based models (NCEP and GLDAS) and a satellite observation model (CM-SAF). The results showed that the calibrated Angstrom model with R2=0. 9 and SEE=2. 58 was the most efficient model. However, the accuracy of this model is strongly depends on the calibration procedure and the existence of sunshine data. The GLDAS model with R2= 0. 87 and SEE=3. 5 was the second most efficient model after calibrated Angstrom model. The GLDAS model, in spite of 10. 2% overestimation of surface solar radiation, can be the most efficient model in areas with the lack of meteorological data.

Measuring flow discharge in open waterways has always been one of the most important concerns for water experts. Flow surface image velocimetry method as a non-contact option has recently been widely utilized to measure discharge in open channels. One of these methods is a type of PIV method named LSPIV which has been paied more attention due to the elimination of laser application. In this study, LSPIV was used to measure 2D velocity field over the surface of a steep supercritical flow. Totally 24 experiments including three different slopes (2, 6 and 10 percent) and eight different aspect ratios (7 to 20. 5) were conducted and in each experiment the flow surface was recorded with a frequency of 125 fps for 60 seconds. The Velocity Index was calculated bt the obtained velocity data. This index is used for convering the surface velocity to average velocity of the cross section and subsequently for determination of flow discharge. The effect of different dimention ratios on VI was investigated. The average value for VI was obtained to be 0. 701 which is differ from the established value (0. 85) by about 17%. Moreover, the flow surface time-averaged velocity patterns were quantitavely compared for different flow conditions. Since, the velocity index has been so far studied for subcritical conditions, the results of this study may be helpfull for measuring supercritical flows.

Sediment tracing method has been proven as a successful and effective method to determining sediment sources contribution in sediment yield in recent two decades. Ziarat drainage basin in Golestan province is one of the water supply resources in Gorgan city. The main lithological formations in the study area are Gorgan Schists, Quaternary alluvial deposits, Shemshak and Khosh yeylagh Formation which could have an important role in erosion and sediment yield. For tracing sediment, 14 samples of suspended sediment from catchment outlet during precipitation events and 43 representative samples of geologic formations (as sediment sources) from the soil surface (depth of 0-5 cm) were collected and geochemical elements, 137Cs and organic carbon were measured in the samples as tracers. The optimum set of tracers was selected by using Kruskal-Wallis test and discriminate function analysis. The results of this study indicate that the tracers including OC, 137Cs and Cu have the most potential to discriminate the sediment sources. The result of the sediment fingerprinting mixing model showed that Shemshak formation, fluvial deposition, Khosh yeylagh and Shist formation have 42, 31/9 and 23/7, 1. 6% of the sediment contributions in sediment yield, respectively.

Kerosene has been utilized as an herbicide in some parts of Khuzestan province, Iran. In the present study, a pot factorial experiment on the basis of a completely randomized design with three replicates was conducted to investigate the effects of kerosene (at six levels including; 0, 2, 4, 6, 8 and 10 ml per kg of soil) on growth and physiological indices of three vegetables (parsley, coriander and carrot) grown in a kerosenecontaminated soil. Furthermore, the accumulation of heavy metals in the vegetables was investigated. Results showed that the biomass and chlorophyll content of the vegetables decreased as kerosene concentration increased. The amounts of prolin and anthocyanin also decreased at high kerosene concentration (with the exception of carrot in which they increased). The amounts of Cd, pb, Zn, and Cu in the root and shoot of vegetables increased significantly by increasing the amount of kerosene in soil. As by increasing 10 ml of kerosene to each kg of soil, the average concentration of Cd, Cu and pb increased in the root (10, 68, 6. 5 ppm) and shoot (4, 88, 2. 5 ppm) of parsley; root (9, 65, 5. 7 ppm) and shoot (3. 3, 83, 2 ppm) of coriander, and root (9, 45, 5 ppm) and shoot (4. 2, 80, 1. 58 ppm) of carrot. Finally, this research indicated that the average concentration of heavy metals in the three vegetables was higher than the world standard level. Hence, high consumption of these vegetables could be dangerous for consumers.

Despite of numerous studies on BTEX biodegradation, a few researches has been conducted to optimize the environmental conditions for biodegradation of this pollutant considering the effective factors. The objective of this study was to investigate the effect of environmental factors such as nitrate, salinity and cell mass (the isolated bacterium from the soil) on BTEX degradation and to optimize the environmental conditions for biodegradation. In order to identify the appropriate microorganism for BTEX degradation, isolation of the bacterium from the oil contaminated soil was performed firstly. Then the nitrate, salinity, cell mass and BTEX concentrations were considered as independent variables to optimize BTEX degradation conditions by the isolated bacterium. Finally, a quadratic polynomial mathematical model was suggested by the Design Expert software (R2=0. 85). This research showed that the isolated bacterium is able to degrade BTEX and the proper condition for degradation can be achieved by applying the above-mentioned model. Results showed that the effect of BTEX and Nitrate concentration on BTEX degradation is significant. So that increasing BTEX concentration to the extent of 200 ppm and decreasing nitrate concentration to the extent of 400 ppm reduced BTEX degradation to 4. 2% and 9%, respectively.

Scouring threaten the stability of hydraulic structures in various forms. One way to indirectly reduce scouring is to put collars and vanes. Collar is a thin plate at a certain height from the base of the bridge which prevents direct contact of down flow in front of the pier with the river bed and undermines the activity of horseshoe whirlpool. Also, in the scouring foundations, the speed of scouring reduces or in other words, the time of scouring is delayed. In this study, using experimental modeling, the researcher investigated the effects of combined collar and vanes on the reduction of scouring depth on cylindrical pier. According to the results of the experiment, the highest scour depth reduction for the Froude number of 0. 246 and the pier in the vicinity of the collar of twice the pier diameter and six submerged plates for each tripod occurred respectively (55%, 96%, 98%). Also, the results showed that submerged plates with impact on stream lines and collars with protection of the pier against downstream vortices and Horseshoe vortices are suitable tools for reducing scour depth in Cylindrical bridge pier group.

Phosphorus is not only the main nutrient of living organisms and the basic materials of many industries, but also it is one of the important parameters affecting the environment. In this study, the effect of different levels of Hexa decyl tri methyl ammonium surfactant concentration on modification of clinoptilolite zeolite was investigated in order to remove phosphate using column tests. For this purpose, the effect of modified zeolite with 0, 10, 20 and 25 mg/L concentrations were investigated using columns with height of 30 cm, diameter of 32 mm and with upward flow. Three common models; Bohart-Adams, Thomas and modified dose-response, with an artificial intelligence model of adaptive neuro-fuzzy inference system (ANFIS) were investigated in terms of modeling the breakthrough curve in the adsorption column, . The results of this study showed that the amount of equilibrium absorption capacity increases from 0. 08 to 0. 23 mg/L with increasing surfactant concentration. The concentration of 25 mg/L with a breakthrough and saturation time of 15 and 225 minutes and an adsorption capacity of 0. 23 mg/g was the best level for modification of zeolite in order to remove phosphorus. The modified dose-response model versus the Thomas and Bohart-Adams models is the most accurate adsorption math model to predict a column breakthrough curve for phosphorus removal. Also, the results of this study indicate that ANFIS is more capable and accurate than the conventional kinetics models in estimating the output concentration from phosphorus adsorption column which results a reduction of 44, 32 and 20% of the average relative error, root mean square error and chi-square, relative to the best mathematical adsorption model.

Due to the importance of trend study of rivers discharges, in this paper, the trend of average discharge variations of the rivers in Urmia Lake basin was analyzed. Investigating the role of discharge changes, entering to the lake on lake’ s surface reduction was another goal of this study. For this purpose, the recorded data of 65 hydrometric stations (during 1978-2011) were analyzed. Non-parametric Mann-Kendall method considering autocorrelation effect was used for trend analysis in this paper. On the basis of the obtained results, discharge time series was significant at 95% confidence level in more than half of the stations (41 stations) having autocorrelation with 1-year lag. Also, more than half of the stations (58 stations) had a descending trend and this trend was significant at 95% confidence level in 38 stations. The average volume of surface water entering the lake have been reached from 4654 MCM in years before 1995 (the starting year of drying) to 2134 MCM in years after 1995. The time series of surface water entering the Urmia Lake had a decreasing trend and on the basis of t-student, the difference between average discharges during the two periods (after and before 1995) was significant at 95% confidence level. The results of this study shows a reduction in the surface waters across the whole basin area discharging to the Urmia Lake during the years after 1995 and the role of this phenomenon on the lake’ s water level fall. This emphasizes that the proper management of water resources in different consumption sectors including agriculture should be considered due to climatological governing situations.

This study has investigated cadmium immobilization in the soil at the present of nano and micro titanium dioxid and the role of humic acid in nanoparticle stability and cadmium adsorption on nano and micro particles. The results of this study showed that in the soil contaminated with cadmium in suspension conditions, humic acid increased soluble cadmium in supernatant suspention and therfore increased cadmium availability in the soil. Modification of TiO2 nanoparticles surfaces with humic acid increases adsorption of cadmium at the nanoparticle surfaces. Also, since microparticles have reduced the soluble cadmium in supernatant suspensions and the concentration of exchangeable cadmium to a greater extend than nanoparticles, it can be concluded that the effect of microparticles in reducing available cadmium in the soil is greater than that of nanoparticles.

Digital soil mapping (DSM) can be defined as a production of spatial soil information. Decision tree (DT) algorithm is one of the most popular machine learning methods which was applied in several recent DSM studies. This study was carried out to evaluate the capability of DT in mapping soils in Miandarband region with area of 50, 000 ha in Kermanshah province. The C5. 0 decision tree algorithm (with and without boosting meta-algorithm) used to establish spatial relationships between known soil taxonomic classes and environmental variables. Using simple systematic sampling, 78 pedons were studied and 6 great groups and 14 subgroups of Soil Taxonomy (ST) were identified. Thirty environmental items were derived from a digital elevation model (DEM) file and a landsat-8 OLI/TIRS (July/Tir 1394) image of the area. Predictions made by C5. 0 algorithm showed OA values of 73 percent for great group and subgroup, while comparable values for Kappa Index were 0. 61 and 0. 63, respectively. Combination of boosting meta-algorithm with C5. 0 increased OA values for ST categories 0. 80 and 0. 76 and Kappa Index values to 72 percent and 66 percent. Results showed a considerable capability for DT in recognition of soil pattern over the study area and the topographic variables seems to be most important. Also, analysis of the produced maps, compared with the observed soil pattern during the field survey, revealed a reasonable agreement of decision tree algorithm predictions with reality.

Estimation and modeling of non-saturated hydraulic properties of the soil is an effective approach to accelerate and facilitate studies on the movement of water and salts in the soil. In this paper, an inverse solution estimation method was used to analyze the results obtained by disk infiltrometer tools. Also, Wooding analytical method and Hydrus-1D software were used to simulate infiltration values and hydraulic properties. In this regard, four lysimeters were used and infiltration experiments were carried out at suctions of 15, 6, 3 and 1 cm. Also, pressure data were recorded by four tensiometers installed in the lysimeters. Finally, the results of the inverse solution method were compared with the Wooding method. The results showed that the inverse solution method was generally in good agreement with the Wooding analysis method. The inverse solution method estimated the unsaturated hydraulic conductivity values close to Wooding method at low suctions, but the estimated values were greater 12% than the Wooding method with increasing suctions.

In this research, the effect of climate change phenomenon on optimal management of water resources in Khorramabad basin was investigated. The developed hybrid model based on the Bayesian approach was used for this purpose. So that initially the output of AOGCM models under the A2 emission scenario during the baseline period 1971-2000 and the future period 2040-2069 were downscaled and 100 examples of the downscaled monthly probability distribution function of the temperature and rainfall were produced based on the weighting method, using the Monte Carlo method and SIMLAB Software. The results indicated that the future long-term monthly average temperature would increase between 1. 93 to 3. 7 oC. The rainfall will increase in some months and decrease in another months. The rainfall variations in the basin under scenario A2 during the period 2040-2069 will be in the range of-17. 29 and 1036. 04 percent as compared to the baseline. Then, by introducing the future temperature and precipitation of the hybrid model into the calibrated and verified IHACRES, the future runoff will be achieved. The results showed a decrease in future runoff rates relative to baseline values. This reduction would be 4. 33 % for the A2 scenario during the period 2040-2069. Finally, different scenarios were investigated by WEAP model and the amounts of water allocation at the baseline and climate change periods were compared. It was found that the seasons (such as summer) in which the water demand and consumption are increased, there would be an unmet demand (failure period) and this situation will be intensified in climate change condition. As the amount of annual unmet demand will be equal to 0. 17×106 m3 and for the A2-2040-2069 scenario, it will be increased by 87% and equal to 1. 33×106 m3 as compared to the baseline.

In recent decades, although dam construction has been increased, but most of them have experienced huge sedimentation problems during operation. To solve this problem scientifically and efficiently, Sediment Bypass Tunnels (SBTs) could be incorporated. SBTs are division channels that transfer the flow containing sediments from the upstream to the downstream of the dam reservoir. In this experimental study, the effect of division channel width on deviated flow rate and sediment rate into the secondary channels has been investigated. For this purpose, Froude number and flow depth as variables were studied in three different widths of the diversion channel. The results of this study reveals that increasing Froude number reduces the deviated flow rate and sediment rate to the lateral channel up to 20 and 44% respectively. On the other hand, 33% width reduction of the diversion channel could result a reduction of 8. 5% in the deviated flow rate and 50% increase in the width could increase 13% the deviated sediment rate into the lateral channel. The performance index was greater than one and ranged from 1. 6 to 3. 77. Hence the 90-degree diversion channel has a good performance for sediment transportation. By decreasing Froude number and increasing flow depth in a diversion channel (with dimensionless width=0. 41), it is possible to find the optimum choice for sediment transportation by which the highest sediments could be deviated by the lowest deviated flow rate.