مجله تحقیقات آب و خاک ایران
سال پنجاه و دوم شماره 5 (پیاپی 65، امرداد 1400)

Optimization of operational performance in irrigation networks is essential for increasing water consumption efficiency in Urmia Lake Basin and its restoration. Various optimization algorithms have been developed. In this research, PSO algorithm with the ability of swarm intelligence and convergence speed was used to optimize the water delivery schedule of Zarinehroud left bank Irrigation Network in two reduced water allocation scenarios. The first scenario follows the Urmia Lake Restoration Plan (ULRP) based on the reduction of agricultural water consumption by 40%; and the second scenario focuses on the delivery of 70% to 90% of network water demand. Suitable values of model parameters have been determined by sensitivity analysis, and used in the modeling of two scenarios. Results of the first scenario indicated that, with supplement of 66% of water demand, the feasibility of 9% increase in water efficiency, 30% and 38% increase in the stability and adequacy indices can be achieved, respectively. In the second scenario, with 82% supply of water demand; the efficiency, stability and adequacy indices could be increased by 25%, 32% and 42%, respectively. The second scenario is recommended due to the gradually reduction of water allocation and greater values of the performance indices, while preserving the dependability and trust of water-users in the Zarinehroud irrigation network.

Due tothe high cost and the need for Experts to use advanced flow measuring equipment in canals, the use of simple, inexpensive and low-cost methods has always been considered by researchers and operating companies of irrigation and drainage networks. In this study, flow measurement in canals has been investigated experimentally using trapezoidal flumes with cylindrical pier in four side slopes. By measuring the flow depth at upstream and downstream of the flume throat, separate relationships and graphs were obtained to calculate the discharge at each studied side slopes on the base of functional relationships (both in free and submerged flow conditions). Also for the studied side slopes, one relation for free flow conditions and two relations for submerged flow conditions were obtained.  Mean absolute relative error (MARE) for calculation of dimentionaless discharge using the obtained relationships under free flow conditions was obtained 6.2, 4.6, 8.1 and 9.4%, and under submerged flow conditions was obtained 25.17, 22.9, 19 and 14% respectively in side slopes (z) of 1, 0.7, 0.4663 and 0.268. The value of  MARE for calculation of dimensionless discharge using the obtained relation for all studied side slopes was obtained 8.2% under free flow conditions and 35.9 and 34.3% under submerged flow conditions (using two related equations). The maximum root mean square error (RMSE) for calculation of dimensionless discharge for the all studied side slopes, was obtained 0.078 under free flow conditions and 0.34 and 0.38 under submerged flow conditions (using two related equations). Then, using the related relation to each side slope (separately) has less error compared to using a relation for all side slopes.

Estimation of actual evapotranspiration (Eta) at the basin-scale using SEBAL, as one of the commonly used satellite-based models, are affected by uncertainties associated with the selection of the anchor pixels, satellite sensors, and the spatial extent of the input satellite images. This study was conducted to investigate the impacts of aforementioned uncertainties on the actual evapotranspiration estimates in Urmia Plain (in the northwest of Iran) using MODIS and Landsat8 satellite imaginaries and the PySEBAL and MPySEBAL (Modified version) models. Validation results using lysimetric data during 2010-2011, showed that MPySEBAL (with cold pixels on well-irrigated vegetation) has less RMSE up to 70% as compared to PySEBAL model. Moreover, in the heterogeneous areas such as Urmia Plain, MODIS data with less spatial resolution leads to a 33 percent overestimation of daily Eta compared to Landsat 8 results. Furthermore, introducing a satellite image at its original extent rather than cropping the study area will result an uncertainty in the daily Eta estimates up to 8%. Comparing the relative impacts of the three sources of uncertainties indicated that the selection of the anchor pixels based on the surface temperature and NDVI thresholds, the spatial resolution of the sensors, and the spatial extent of the input images introduce the largest uncertainties respectively. Findings of this study can be used to enhance the accuracy of satellite-based Eta models and estimation of the irrigation water consumption from filed to basin scales.

Due to the scarcity of water around the world especially in arid and semi-arid regions, accurate determination of crop water requirement is essential for proper irrigation planning and management. One of the common methods for estimating crop evapotranspiration is the use of reference evapotranspiration and crop coefficient (Kc) (or the FAO-56 Kc-ETo approach). Different climatic conditions, plant variety, and differences in crops, soils and irrigation management practices result in variations in crop coefficient for the same crop between the locations, therefore locally developed Kc values are necessary for more accurate estimation of crop evapotranspiration. The aims of this research were to estimate silage maize crop coefficient using water balance method under pulsed drip irrigation system during two growing seasons (spring and summer) and to develop an equation to calculate silage maize crop coefficient based on growing-degree-days in Varamin. Silage maize actual evapotranspiration based on water balance method was 465 and 373 mm for spring and summer growing seasons respectively. Silage maize crop coefficient for initial, mid and late growth stages of spring and summer growing seasons were calculated 0.24-0.27, 1.28-1.3 and 0.8-0.88 respectively. The results showed that using silage maize crop coefficient proposed by FAO-56 caused 8% underestimation in crop evapotranspiration. Significant difference ( ) was found between  and , while using the equation presented in this study estimates silage maize evapotranspiration reasonably well, with the mean absolute error (MAE) of 0.53 mm/day, the root mean square error (RMSE) of 0.7 mm/day and the agreement index (d) of 0.98. Therefore, using developed regionally based and growth-stage-specific Kc helps in irrigation management and provides precise water applications for this region.

Under water scarcity and drought conditions, proper irrigation methods and suitable cropping pattern are among the priorities of agricultural studies. In this research cropping pattern modification of Citrus gardens to Piyarom dates are investigated by evaluating economic benefits and water productivity, considering cases of water scarcity and sufficient water in QiroKarzin region of Fars province. Water productivity of Piyarom dates and citrus under water scarcity condition were respectively 22% higher and 16% lower than those obtained in sufficient water condition. Results also indicated that in large gardens of the study area for both water scarcity and sufficient water conditions, replacement of part or all of citrus orchards with Piyarom dates would be beneficial, based on the ratio of profit to cost and net profit per volume of water consumed and also the amount of water consumption. However, in small gardens under water scarcity condition, Piyarom dates cultivation and under sufficient water condition, citrus cultivation would be the appropriate alternatives.

In this research, the simulation and optimization models are integrated to apply the reservoir hedging policy. Simulation of the studied basin was executed using the WEAP model to operate the Doiraj Dam reservoir located on the Doiraj River. In addition, the multi-objective MOICA model was utilized to optimize the system, in which the first objective function (maximizing the percentage of supplying demands), and the second one (minimizing the violation of allowable capacities of the reservoir during the operation period) were considered. In this regard, the operation modeling from the reservoir was carried out based on the current condition for a 720-month period (October 1960 to September 2019). Finally, by defining the optimization scenario and applying the reservoir hedging policy, the operation optimization of the reservoir was done and the results were compared with the reference scenario results. In this study, by considering 24 decision variables including 12 hedging level variables and 12 hedging coefficient variables, the optimal answers were achieved after 1000 iterations. The results showed that the violation of the allowable capacities did not occurred in any periods of the optimization scenario, while in the reference scenario the reservoir level reached the dead level in sequent months with more water shortage which might lead to the lack of water supply in such months and serious damages to the system. Due to the application of hedging policy in the optimization scenario, the percentage of supplying the demands in the critical months is increased between 20 to 35% as compared to the reference scenario, which indicates a significant reduction in the failure rate in such months.

The purpose of this research was to investigate the response of evapotranspiration components of maize to different levels of water stress. This research was done as a completely randomized design. Treatments were irrigation at four levels; 100(I0), 80(I1), 60(I2) and 40(I3) percent of the crop water requirement. Daily crop evapotranspiration was measured based on soil water balance in a mini-lysimeter. Mini-lysimeters with and without mulch covering on the soil surface were used to separate the amounts of evapotranspiration components. The amounts of evapotranspiration components (ET, T and E) during the growing period were measured to be 424.5, 267.3 and 157.2 mm (in I0), 405.8, 245.4 and 160.4 mm (in I1), 360.5, 194.4 and 166.1 mm (in I2) and 303.7, 125.5 and 178.2 mm (in I3) respectively. The results showed that from I0 to I3, the amounts of ET and T decreased to 28.4% and 53% respectively, and the E amount increased to 13.4%. Therefore, in water stress conditions, the T portion was decreased to 35% and the E portion increased to 35%. The most amount of T occurred in the developmental period and the most amount of E occurred in the initial and final growth stages. But the highest response of transpiration and evaporation to water stress occurred in the middle period, in which transpiration decreased to 69% and evaporation increased to 253%. The existence of sensitive stages in the middle period of growth caused water stress to be most effective. The results indicated a reduction in transpiration and an increasing in evaporation in deficit irrigation conditions. Therefore, covering the soil surface and applying the suitable level of water stress in irrigation management will be effective factors for increasing the water use efficiency.

Element efficiency is one of the most important characteristics of different plant cultivars for managing nutrition and fertilizer application in plants. This study was carried out to investigate the efficiency of silicon in different maize cultivars in a calcareous soil under greenhouse conditions. Treatments included five maize cultivars (single crosses 400 (ksc400), 410 (ksc410), 704 (ksc704), 705 (ksc705), 706 (ksc706)) and two silicon levels (0 and 100 mg silicon in 1 kg soil from potassium silicate source), which was performed in a factorial arrangement based on a completely randomized design. After eight weeks of vegetative period, plants harvested and factors such as shoot and root dry weight, leaf area, root volume and surface area and plant silicon uptake were measured. Efficiency element indices including adsorption and consumption efficiency of silicon and silicon efficiency of different cultivars were calculated. Among cultivars, ksc706 with 14.54 g yield, root weight of 6.7 g, leaf area of 173700 mm2 and root area of 185185 mm2 had the best results in terms of morphological characteristics and ksc410 cultivar with yield of 10.03 g, root weight of 5.25 g, leaf area of ​​2147900 mm2 and root area of ​​136284 mm2 showed the lowest desirable characteristics, compared to the control treatment. Yield increase of cultivars compared to the control treatment were: ksc400 (20.7%), ksc706 (17.8%), ksc410 (9.2%), ksc704 (8.9%) and ksc705 (4.8%). The highest silicon uptake efficiency was in ksc706 cultivar (85.7%) and the lowest in ksc704 (58.9%), and the highest silicon consumption efficiency was in ksc705 (12.52%) and the lowest in ksc400 (5.44%). With regard of increasing the area of root system in the treatment containing silicon compared to the control, and the effects of silicon on the uptake and transfer of more nutrients from the soil to the shoots, an increase in plant yield is evident. Accordingly, it is suggested to consider the development of planting the effective element plants with the aim of managing input consumption, soil fertility and sustainable agricultural goals.

Microplastics are plastic particles smaller than 5 mm that are known as emerging contaminants. Most research about microplastics has been performed in aquatic ecosystems and there is limited information about the effects of these particles on soil biological and enzymatic properties. Therefore, the aim of this research was to evaluate the effect of Microplastic particles on some soil properties included basal and cumulative respiration, microbial biomass carbon as well as soil acid and alkaline phosphatase activity. For this purpose, Low-density polyethylene (LDPE) microplastic particles (diameter 0.5 - 1 mm) added to the soil (1, 2 and 4 % w/w). Incubation times for investigation of soil properties and enzymes activity were 87 and 45 days, respectively. The results showed that the microplastic particles increased the soil basal and cumulative respiration rate. Soil microbial biomass carbon increased during the 3th to 17th days of incubation, but decreased after that when compared to control treatment. LDPE Microplastic particles had a negative effect on the activity of acid and alkaline phosphatase and decreased them. The highest decline was related to the microplastic level of 4%. The rate of decrease in acid phosphatase activity was more than alkaline phosphatase activity. Briefly, the results of the present study showed that the microplastic particles can increase soil respiration, but it has a negative effect on phosphatase activity.

One of the methods of controlling and reducing flow energy is to use energy dissipating structures through formation of hydraulic jumps. One of these types of structures is the constriction elements in the flow path, which leads to a decrease in the energy of the passing flow. In the present study, the effect of crescent-shaped contraction as an energy dissipating structure in the supercritical flow path has been investigated using FLOW-3D software. Examining the simulation results, the RNG model among the four turbulence models, RNG, k-ε, k-ω and LES was selected due to its higher accuracy and lower relative error and absolute error percentage. In this study, the amplitude of the Froude number after the gate as the most effective dimensionless parameter in energy dissipation varied from 2.8 to 7.5 and the values of stenosis on both sides are 5 and 7.5 cm. The results show that in all cases of using the crescent-shaped contractions, the energy dissapation in 5 and 7.5 cm contractions are respectively 24.62% and 29.84% more than the ones in the classic free jump, based on the energy drop relative to the upstream, and 46.14% and 48.42% more, based on the energy drop relative to the downstream. Also, by reviewing the previous researchs, it was found that the crescent-shaped contractions have a better performance in terms of energy loss compared to the sudden contraction. Based on the simulation results, with increasing the upstream Froude number, the energy dissipation is increased relative to the upstream and downstream of crescent-shaped contraction, so that the use of contraction elements reduces the downstream Froude number of the contracted section in the range of 1.6 to 3/2.

New approaches in analyzing the status of basic water resources data in the WA+ framework have been able to be introduced as a standard method in water resources accounting. In this study, with WA+ water accounting approach, evaluation of basin evapotranspiration was performed to determine water productivity. According to the amount of rainfall in the region, the transfer flow from Karoon basin, the shortage of water resources, outflow from the basin and evapotranpiration in each land use class, the resource base sheet was calculated. Then, by calculating the evapotranspiration sheet, benefical and non-benefical consumptions were separated from each other. In the sheet of agricultural services, the water demand of the products in each landuse was calculated and finally the water and land productivity for the priod 1396-97 was obtained. The results showed that of the 548.8 million cubic meters of water entering the system, 465.5 million cubic meters are evapotranspirated and 41.9 million cubic meters are surface flowed. In the second sheet, for representive crops in land use, the amount of evaporation, transpiration and interception were extracted with Wapor product. Accordingly, 264.3 million cubic meters was determined as a benefical volume in agricultural and environmental activities and 201.1 million cubic meters as non-benefical evapotranspiration. Also, the amount of water productivity in each land use class was determined based on the biomass of the products of each land use. The results of this worksheet showed that the managed water lands had the highest water productivity of 1.28 kg/m3. The results of water accounting system (WA+) in Plasjan basin indicate a high volume of non-benefical evapotranspiration and water loss, and suggestions for management measures to reduce this issue should be considered.

Double Ring (DR) and Time of Ponding (TP) methods are two field methods for determining infiltration rate in the sprinkler irrigation system. However, the boundary conditions and the nature of the flow on the soil surface in the sprinkler irrigation system are different from the DR method. The aim of this study was to investigate the relationship between the measured infiltration intensity values with the double ring and ponding time methods in different soil textures. The first factor consisted of two methods and the second factor consisted of five soil textures in Isfahan province and the experiments were performed in three replications in the form of a factorial statistical design. The results showed that the infiltration intensity values obtained from the DR method were on average 2.7 times higher than the values determined in the TP method and the final infiltration values of the DR method were 5 times higher than those of the TP method. The difference of infiltration values was higher in the fields with coarser texture (sandy clay loam) and less in the field with clay loam texture. The maximum final infiltration rate was observed in the field with loamy sand soil texture and the minimum final infiltration rate was observed in the field with clay loam soil texture. The results indicate the need to adjust and correct the final infiltration of DR method in the design of sprinkler irrigation systems. It is suggested to use TP method to determine the infiltration velocity values for designing sprinkler irrigation systems. If DR method is used, it is recommended that the infiltration values be modified with the given development equations before application.

Vortex Settling Basin is an efficient structure for separating sediments in irrigation canals and water and wastewater treatment plants. In this study, experiments in a laboratory basin model were performed to investigate the efficiency of trapping, sedimentation and volumetric fraction in the hydraulic laboratory of Water Science and Engineering Department of Ferdowsi University. The effect of inflow, central orifice diameter, Particle diameter, end sill height, and outlet end weir height on trapping and sedimentation efficiency of the Vortex Basin was investigated using Taguchi and Response Surface Methods. The results showed that in the range of proposed parameters in this study, the inlet flow is the most effective (%40) and the orifice diameter is the least effective (%0.4) parameter for trapping efficiency, and the particle diameter is the most effective (%43) and the outlet end weir height is the least effective (%6.90) parameter for sedimentation efficiency. An experiment with %75.48 trapping efficiency, %67.74 sedimentation efficiency and a small amount of sediment deposited on the floor was determined to be optimal due to a significant reduction in water loss (%8.46). The optimum situation was obtained for a basin with inflow of 22 L/s, orifice diameter of 0.07 m, end sill height of 0.05 m and weir height of 0.03 m. Finally, high- precision relationships were presented to calculate trapping, sedimentation and volumetric fraction.

In order to evaluate the effect of humic acid and complete micronutrient fertilizer on growth and economic performance of different bread wheat cultivars, a factorial experiment was conducted on the base of randomized complete block design with three replications in Biranshahr region (Lorestan province) during two years in 2015-16 and 2016-17. The main factors included nutrition at four levels (control, humic acid, complete fertilizer 20-20-20 and humic acid + complete fertilizer 20-20-20) and bread wheat cultivars as sub-factors included (Mihan, Sivand and Alvand). The results showed that the number of spikes per square meter, number of seeds per spike, 1000-seed weight, biological yield, and grain yield and harvest index of wheat cultivars were influenced by the studied factors. The highest economic yield (8296 kg/ha) was obtained in the treatment of humic acid application + complete micronutrient fertilizer in Alvand cultivar. The highest number of spikes per m2 was related to humic acid feeding treatment in Alvand cultivar with an average of 625 spikes per m2. The highest number of seeds per spike was obtained in the treatment with humic acid feeding along with complete fertilizer in Alvand cultivar with an average of 45.2. The highest 1000-seed weight was related to feeding with humic acid + complete fertilizer with an average of 42.0 g. Interaction of humic acid with complete fertilizer in Alvand cultivar has produced the highest biological yield (19156 kg/ha). The highest harvest index (43.6%) was observed in complete fertilizer feeding treatment in Alvand cultivar. Findings showed that the application of humic acid along with chemical fertilizers increases the quality and quantity of agricultural products and maintains the balance of the environment.

One of the most important ways to deal with the water shortage crisis is to increase water productivity in the agricultural sector. In this regard, identifying the factors affecting water productivity is of great importance in adapting to this issue. Therefore, the present study was planned and conducted to investigate the factors affecting water productivity in innovative farmers compared to non-innovative. The research is applied in terms of purpose, how to collect descriptive-correlational information and the amount and degree of control over variables. In this study, a total of 317 questionnaires were completed and collected. Farmers are divided into two groups based on relative productivity: innovative farmers (77 (24.4%)) and non-innovative (238 (75.6%)). The mean total score of factors affecting water productivity in non-innovative was 2.83±1.23 (the total score was 5), while this score was 3.42±1.36 (the total score was 5) in innovative farmers. The highest difference in scores (positive) in the factors affecting water productivity among innovative and non-innovative farmers are related to the items "comprehensive view and attitude to all factors in the production chain", "use of proper planter" and " implementation of irrigation systems by experienced experts". For better performance of farmers, especially in their weaknesses, technical and infrastructural measures as well as improving their knowledge are needed. It is suggested that training classes be held for this purpose and that the knowledge of innovative farmers be used in these classes.

The maximum value of soil detachment due to overland flow is the soil detachment capacity. The present study aimed to evaluate the effect of particle size classes on the rill detachment capacity (Dc) in Saravan watershed (North of Iran). For this purpose, the variations of Dc have been measured on soil samples with three particle size classes (0-1, 1-2 and 2-3 mm) under laboratory conditions through a flume experiment at five slope gradients (4.1 to 38.3%) and five flow rates (0.26 to 0.67 Lm-1 s-1) with five replications. The results showed that the Dc in 2-3 mm class was significantly higher than the other particle size classes (p < 0.05). The unit stream power was found to be very accurate predictor of the Dc in forestland of Saravan watershed. Rill erodibility, which calculated by relationship of the Dc and the water flow shear stress, had the lowest value in 0-1 mm class. Overall, this study has confirmed that the particles with size larger than 2 mm on steep slopes are more susceptible to erosion and separation by surface runoff in delicate environment ecosystems, such as the Saravan Forest Park in Northern part of Iran.

Lead (Pb) and cadmium (Cd) are among heavy metals which enter water, soil, plants and ultimately the human and animals food chain from various resources. Several methods has been suggested for remediation of contaminated soils which are mostly very expensive and therefore the use of less expensive methods to remove contaminated soils can help to purify and use these lands optimally. Phytoremedian is one of the low cost and environmentally friendly methods. Use of chelates is one of the effective approaches for increasing the bioavailability of heavy metals. Therefore, In this study, the effect of Ethylene Diamine Tetra-acetic Acid (EDTA) as a chelating agent on incresing absorption of Pb and Cd by Wheat (Bahareh) were studied. A pot experiment was conducted in the greenhouse with a factorial and completely randomized design with three replications. Factors including: 1- EDTA application in two levels (0 and 2.7 mmolkg-1 soil), 2- Pb at three levels ( 0, 150 and 500 mgkg-1 soil) and 3- Cd in three levels (0, 3 and 10 mgkg-1 soil). Consequently, a non-contaminated soil was selected and contaminated with different amounts of Pb and Cd. Then, Wheat seeds were planted and after harvest, Pb and Cd concentration in plants (grain and straw) and soil was measured. The results showed that EDTA application was able to increase Pb and Cd solubility in soil solution, resulting an increase in absorption of Pb in straw (12.5 times) and grain (68.8 times) and Cd in straw (26 %).

Estimation of runoff in a catchment area is important from various aspects such as dam reservoir management, water resources management, flood regulation, and erosion control in river banks and bed. In the present study, a conceptual model of HBV and an intelligent model of Random Forest (RF) were used to simulate the rainfall- runoff process in Bazoft watershed at the Landi hydrometric station during the period of 2010 to 2017. In order to evaluate the performance of models, the statistical criteria, including Correlation coefficient (r), Root Mean Squares Error (RMSE), Nash-Sutcliffe efficiency coefficient (NS), Mean Absolute Percentage Error (MAPE), and Mean Absolute Error (MAE) were used. Comparing the results of HBV and RF models revealed that the RF model outperformed the HBV. Thus, the RF model with r=0.95, NS=0.82, MAPE=9.59, MAE=0.25, and RMSE=0.39 m3/s was selected as the top model which might be used as a new choice to predict runoff in Bazoft watershed.

Accurate estimation of reference evapotranspiration (ETo) in each region is necessary due to its significant contribution to water resources management and proper irrigation planning.  Since direct (ETo) measurement methods are time consuming and costly, therefore, in many cases, experimental and mathematical models are used for this purpose. These models, however, can’t be used unless they are validated and verified using lysimetric data. A various methods can be used to estimate evapotranspiration; but the performance of these equations are varied from one climatic condition to another. Therefore, in the present study, lysimetric data have been used to evaluate 15 ETo estimation models in Aleshtar region. The data required in different (ETo) estimation models were collected from Aleshtar synoptic station. According to the statistical evaluation results, the Jensen- Haise (RMSE = 1.14) and Turk (RMSE = 1.42) models from the radiation group and the Hargreaves–Samani (HS) model (RMSE = 1.72) from the temperature group were found to be the most accurate ETo estimation models in the study area. On the other hand, Meyer (RMSE = 4.78) and WMO (RMSE = 4.73) models from mass transfer group were found to be the least accurate ETo estimation models, respectively. Finally, taking into account the significance of the FAO Penman-Monteith model in evapotranspiration calculations, comparing lysimetric data with the values estimated ​​by this model showed that the FAO-Penman-Monteith model ​​(RMSE = 5.83 and R2= 0.10) has the least accurate to estimate ETo in the region.

The most common approach adopted for flow resistance in open-channel hydraulic is the Manning equation. Since the Manning roughness coefficient considers the water depth and flow velocity as constant and the flow conditions in rivers are non-uniform, it is necessary to adjust this equation by considering the geometric and hydraulic characteristics of the rivers. Accordingly, this paper presents a three-parameter flow resistance model, which is a more general form of the Manning equation. The parameters of this model were calibrated by using measurements of 8 sections of a coarse bed-river, Deryuk in Mazandaran province, which has vegetation on its banks. Shear speed was calculated using three methods of boundary-layer characteristics; parabolic law, two-point and the implicit approach, Darcy–Weisbach. The results showed that the Darcy-Weisbach implicit method has high accuracy in estimating flow resistance. Also, the validity of the results was confirmed by comparing the flow discharge calculated by the model with the measured flow discharge. The results showed that the three-parameter model in 75% of the sections had a better estimate than the Manning equation. Also, the average error percentage of the proposed model was 24%, while this value was calculated 32% for the Manning equation.