مجله آبیاری و زهکشی ایران
سال سیزدهم شماره 5 (آذر و دی 1398)

Desirable performance of emitters is the most important factor in increasing the efficiency of micro irrigation systems. But, the pressure variations in these systems and the different sensitivity of the emitters to these changes lead to a non-uniform distribution of water. In this study, pressure-compensating emitter (PCOD-4), dripline (PCID-4), variable discharge emitter (OD-V) and bubbler (B-60) were evaluated based on American Society of Agricultural Engineers standard (ASAE) to find the best pressure range to achieve the ideal emitter's performance. The study results show that in the all experiment pressures, the OD-V dripper performance was not optimal and the uniformity parameters of the PCOD-4 and PCID-4 drippers in the 1 and 1/5 bars and for B-60 emitter in the 2 and 2/5 bar pressure were perfect and Their performance at other pressures was less than expected values. Therefore, it has been suggested that the mentioned emitters be used in optimal conditions and for other emitters the best pressure range should be found in the experimental tests. The design and management of the micro irrigation systems should be done based on these results.

The agricultural sector is the main water user in Iran. Water resource constraints have led to the use of new technologies, including greenhouse cultivation, for optimal utilization of these resources. Climatic conditions management is very important in greenhouse cultivation. To investigate the climatic conditions and spatial and temporal distribution of humidity (vapour pressure deficit) and transpiration, a study was carried out in a commercial greenhouse managed by the beneficiary, with an area of 4333 m2 with four 24-hours measurements in cold and warm seasons. According to growth stage (height and vegetation volume) 21-33 data loggers recorded temperature and relative humidity in two horizontal levels inside the greenhouse. The study of the distribution of vapour pressure deficit according to existing criteria showed that, despite the desirability of the average range of vapour pressure deficit, their distribution in different hours of the day and at the greenhouse level can be very variable and range from unfavorable to desirable conditions. The distribution of transpiration was almost in line with the distribution of vapor pressure loss in the greenhouse. The percentage difference between the maximum and minimum transpiration of changes in total daily transpiration at the greenhouse level in winter measurements was 21 to 46 in the greenhouse and 28% in the spring. As a result, the expression of the climate of a greenhouse only be using the average climate parameters lead to an error in the climate conditions of the greenhouse, irrespective of spatial distribution (at the greenhouse level) and time (day and night). Also, recognizing differences in the amount and distribution of transpiration can be used to optimize irrigation programming with the aim of increasing efficiency and reducing water consumption.

The problem of salinity of water resources and lack of quality water resources is one of the main threats to agricultural development in arid and semi-arid areas such as Khuzestan. Regarding existing problems, low irrigation method, using high salinity drainage, planting salinity resistant plants, and increasing water productivity are good management options. So, a study was conducted to determine the water sensitivity coefficient, salinity stress and Kochia water productivity in salinity and low water stress conditions in Ahvaz. The present study was carried out on Kochia plant at four salinity levels including Karoon river water (as the control with EC equal to 2.5 dS/m), 10, 15, 20 (dS/m) (S1, S2, S3 and S4, respectively) as the main factor and three levels of water deficit including 100, 75 and 50% water demand (I1, I2 and I3 respectively) as the sub plots in three replications (R1, R2 and R3) and as lysimetric in split plot and complete block designs. According to the results, the salinity stress coefficient in this study was between 0.06 and 0.89. The results showed that the coefficient of salinity decreased (Ks) by increasing water salinity. Also, the results showed that the Ks coefficients obtained in combination of salinity stress and 50% water deficit were higher than 75% water deficit stress. The average of Ky coefficient obtained in this study in under deficit irrigation conditions of 75% and 50% of water requirement was 0.19 and 0.60, respectively, indicating that Kochia has a low drought coefficient, which indicates high tolerance of this plant is not affected by severe drought stress conditions. The results also showed that the water productivity in the forage production of the Kochia plant is acceptable and high even under severe stress conditions, combined with salinity and water deficit. In this research, it was observed that salinity reduced water productivity and water utilization in deficit irrigation conditions was more than full irrigation. In general, the results of this study showed that kochia can be used as an appropriate forage plant in areas such as Ahvaz, where irrigation water and soil are not of desirable quality even without the need for leaching and soil remediation, which would cost a lot to producers.

An accurate prediction of friction coefficient is one of the most important issues of water engineering. Due to the complexity of hydraulic phenomena and the influence of various parameters in its estimation, it is difficult to determine the governing equations and the classical mathematical models are not sufficiently accurate in this regard. In this research using 300 experimental data, the friction factor of rainwater pipes with different boundary condition (rigid and deposited beds) under three scenarios (first scenario was modeling based on the hydraulic parameters, the second and third scenarios were modeling based on the hydraulic parameters and the sediment particles characteristics without and with considering the sediment discharge as input parameter) was estimated using Gene Expression Programming (GEP) method and the impacts of different employed parameters in each boundary condition was assessed. Also it was observed that for rigid boundary state, the model including parameters of dimensionless sediment discharge, Modified Froude number, dimensionless particle number, and relative flow depth (Cv, Frm, Dgr, d50/y) and for deposited bed state, the model with parameters of relative depth and width of sediment bed, Modified Froude number, and dimensionless sediment discharge (ys/D, Frm, Wb/y0, Cv) led to more accurate outcomes. One of the capabilities of gene expression programming is providing the explicit formula for roughness coefficient. The best results was obtained for deposited bed with values of R=0.9, DC=0.73, and RMSPE=10.9. Therefore, explicit equations were presented for the superior models of the considered scenarios. Also, according to the results of analyzing data series separately lead to more accurate outcomes in compared to the mixed data and combining the data sets reduced the performance of the model.

Rivers are always one of the most important sources of water. In recent years, due to droughts and the entry of various pollutants, there have been many concerns about river quality conservation. Evaluation of the effective factors on the quality of river water quality management component is the first step of the rivers modeling. The aim of this paper is to evaluate the amount of Dissolved oxygen changes in the Sefidrud River by changing the parameters affecting it. To achieve this goal, after calibration and verification the results of simulation of water quality parameters using the Qual2kw model, the sensitivity analysis of this model was performed using YASAIw software. The data used in the present paper consists of the hydraulic data (depth, Velocity, Discharge), quality and pollutants input to a range of 110 kilometers in sefidrud River during December 2007, July, October and November 2008 and February, April, June and August 2011 at 12 sampling stations. The results showed that the minimum and maximum of normalized root mean square error (nRMSE) for calibration and validation phases for the pH parameter was 0.06 and 0.04 respectively, and for the total phosphorus parameter was 1.08 and 0.96, respectively. Also, the results of the sensitivity analysis of the model showed that the Dissolved oxygen in the Sefidrud River showed the highest sensitivity to the reaeration coefficient, the flow depth power and the decay rate of biochemical oxygen demand, respectively.

Water is one of the most fundamentals demands of human society. Water consumption in industry, agriculture and household consumption, and also the lack of this source result in more extraction from groundwater sources. Irregular extraction from aquifers in dry condition of recent decades lead to significant drawdown in this sources. Recharging of the aquifer by injection wells is one of the solution for revival of the aquifers. The main purpose of this study is to investigate the effect of the injection well in recharging of the unconfined aquifer by using meshless local Petrov-Galerkin. The approximation and weight functions are moving least squares and cubic spline functions respectively. The groundwater table in unsteady extraction mode simulated. The achieved results compared with finite difference, finite element and analytical method. Small amount of error of meshless method indicated the suitable accuracy of this method. Then the aquifer simulated in recharge mode. The height of water rise in the aquifer because of injection well, computed. Finally sensitivity analysis carry out on transmission coefficient, specific yield and rate of flow parameters. The height of water has more dependency to transmission coefficient and rate of flow than specific yield.

Details are given of an experimental study of the effects of changes in concentration of pollution on longitudinal and transverse dispersion coefficients in saturated porous media. A 2D physical model was constructed to enable observations and measurements to be made of pollution transport through a saturated horizontal layer of sand of 0.18 m thickness. Water soluble sodium chloride salt with 5 different concentrations, i.e. 2.5, 5, 7.5, 10 and 12.5 g/l, was used as a tracer. Tracer concentrations were estimated in different time steps by means of an equation, which was derived from the analytical solution of the original 2D Advection-Diffusion equation, involving optimizing longitudinal and transverse dispersion coefficients. The estimated results were compared to the measured laboratory data. According to the results, increasing concentration leads to decrease in longitudinal dispersibility values and increase in transverse dispersibility values. It was found that tracer's diffusion speed in the longitudinal direction is more than its speed in lateral direction. In fact, contribution of advection in transmission of pollution is greater than contribution of diffusion. Based on the results, the usable value of the tracer's longitudinal distribution coefficient in measured conditions and for all the concentrations, mentioned above, is equal to 1/53*1013 meters and the values of the transverse dispersibility coefficients of the above-mentioned concentrations are 27800, 26400, 25800, 25200, 24900 meters. Meanwhile, decrease in longitudinal dispersion was negligible by taking more distance from the tracer release source. However, transverse dispersion values increased with taking more distance from the tracer release source.

The precise simulation of water and solute transfer in porous media is very important in soil and water studies. The purpose of this study was to measure and simulate water movement and solutes transfer of layered soils. In this study, the effect of soil bulk density changes and different soil layering on water and solute movement were measured and simulated with HYDRUS-1D model in 5 treatments and two replications. For this purpose, 10 columns of PVC with a height of 105 cm and an inner diameter of 31.5 cm, and three soil textures including loamy sand, sandy-clay loam and clay loam were used. The columns were irrigated with irrigation water and saline water with salinity of 0.67 and 4.46 ds/m, respectively. During the experiment, moisture content (using TDR moisture meter) and salinity (by saturated mud extraction method) were measured at depths of 10, 20, 30, 40 and 60 cm. The results of the study showed that the water movement in the soil is affected by the position of the layers with the least permeability and when the fine texture layer is placed on top, the time of water exit is the highest. Also, the results showed that in all columns the EC value was the highest in the upper layer and decreased from top to bottom regardless of the order of the arrangement of the layers. The survey of the nRMSE index indicates the high accuracy of the HYDRUS model in simulating the movement of water and solute in the layered soil. The lowest error in simulation was in homogeneous soil.

Due to the location of Iran in dry and semi-arid climate, heterogeneous distribution of precipitation and also the occurrence of a climate change phenomenon has caused phenomena such as floods, drought, desertification and dust production and also creating the different economic, social and environmental damages. One of the primary strategies to reduce these losses, is prediction of the precipitation events. The goal of the present study is monthly precipitation prediction with using data mining methods of decision tree (M5) and K-Nearest Neighbor (KNN) algorithms and Comparing these methods in order to determining more efficient method in the field of predicting the precipitation using monthly meteorological data of Birjand synoptic station during the statistical period 1961-2010 in three cases the raw data, the three-year moving average and the five-year moving average in the Weka software. The results showed that in all defined scenarios, the tree model M5 has more ability than the KNN model to predict the monthly precipitation of the station. Also after investigation of the evaluation criteria R, RMSE, MAE and NS, the fifteenth scenario with input variables such as mean difference of maximum and minimum temperature, average relative humidity, average wind speed and cooling degree days (base 21 ° C) in every month was determined as the best scenario for predicting the same month precipitation. Also the obtained results from comparing the defined scenarios in each model in three states raw data, three-year moving average and five-year moving average show that in most scenarios The five-year moving average on average, with the values of R=0.90445, RMSE=6.0543 and MAE=4.78035 in the M5 model and on average, with the values of R=0.83689, RMSE=7.69825 and MAE=5.595 in the KNN model offers more accurate prediction of monthly Precipitation.

Construction of weirs in river bends results in the poor performance of intake structures on both sides of the river. The hypothesis for consistent distribution of flow across a bend is the uniformity of unit flow rate over the weir via the change of the spillway-crest profile from horizontal to sloping crest. The main aim of the present study was to simulate flow pattern upstream of sharp- and broad- crested weirs across a 90- degree laboratory channel bend, using FLOW-3D model. The simulation results were compared with corresponding 32 test results from independent physical model and from FLUENT model studies. The stability and sensitivity analysis was carried out to set up for the turbulence model, turbulent mixing length, roughness height, numerical grid sizes, and run time. The RNG turbulence model was better adopted; the turbulent mixing length was about 7% of head water over the weir crest; the size of numerical grids was optimized with 0.02 m; and the run time was about 60 seconds. Modeling results were not sensitive to the turbulent mixing length and roughness heights of the channel. The results indicated that horizontal crested weirs are sufficient outside the bend. Sloping crest weirs provide better convergence of the unit flow rates across the bend in sections between 30 and 60 degrees. It was proved that the slope of the weir crest is to be in the range of 2º to 5º toward the outer bank of the bend. The broad-crested weirs are superior within the channel bend.

This research was carried out to investigate the effect of different potato sowing pattern on yield and water productivity under sprinkler and drip irrigation system during 2012 to 2014. The study was carried out as split plot based on randomized complete block design with three replications at Ekbatan Station, Agricultural Research Station and Agricultural and Natural Resources Research Center of Hamadan Province. Two irrigation methods ( sprinkler and drip irrigation system) as main plots and 4 sowing patterns as sub- plots including: conventional method with spacing of 75 cm, two-row planting on combined hill with spacing of 75, 60 or 50 cm were evaluated. Comparison of the combined mean of the results showed that all three sowing patterns with wide hill (two row planting with 75, 60 and 50 cm spacing) with 40.96, 42.67 and 41.75 t / ha respectively are located in higher statistical group than conventional planting with 40.50 t. ha-1. There was a significant difference between yield, water productivity, Seedling emergence and plant overlapping time in two irrigation systems. Water productivity in drip irrigation was 34.4% higher than sprinkler irrigation system. Using the sprinkler irrigation system with wide hill increased water productivity relative the conventional cultivation of potatoes. While the water productivity in conventional sowing pattern in drip irrigation method was higher than the two-row sowing pattern with combined hill (wide hill). Also, the results of this research showed that using of strip drip irrigation can provide better conditions for Seedling emergence and faster plant growth and Compensate part of the lost planting date for late cultivated plants.

Debris flow breaker structure is known as a structure with simple, applicable, reliable, and economic design for preserving the downstream. The structure is able to drainage the debris flow, and therefore, reduces the volume of debris toward the river downstream and decreases the damages to downstream. In this study, dimensional analysis was carried out in order to investigate the structure behavior against debris flow. The structure performance was evaluated by calculating the structure efficiency and dimensionless parameters of distance traveled by the debris and location of the maximum height of the debris accumulation on the structure. Structure performance was investigated by changing in the opening, its building, and the establishment of an integrated barrier on the structure with different concentrations and velocity of the debris flow. The results showed that debris flow velocity is affected by flume slope. The amount and state of opening in the structure are the most effective parameters in the structure performance. With a 40% reduction in the structure opening, the efficiency increased by 95%. Change in the building of the structure has increased the structure efficiency by 44%. The application of an integrated barrier to the breaker structure, in addition to increase the efficiency of the debris control, has reduced the length of the distance traveled by the debris until the final stop and the length of the clamor in the upstream of barriers.

Considering the importance of cotton in crop rotation and the high reduction of cotton cultivation in recent years, it is necessary to use new approaches to increase the cultivation area, production amount and to reduce the production cost of this strategic crop. One of these strategies is the delayed cotton cultivation in the form of transplanting method by using earliness cultivars. This method can be used to plant cotton after wheat in a crop rotation and due to shortening of the growth period and without dealing with cold, an acceptable amount of crop can be obtained. Managing the time and amount of irrigation plays an important role in delayed plantings. In this regard, it is necessary to determine the optimal amount of water used by cotton in transplanting and conventional methods. This experiment was carried out in a split split plot design with three repetitions with transplanting and direct treatments as main plots, irrigation frequency including irrigation after 70, 105 and 140 mm cumulative evaporation from evaporation pan as subplot, and various water quantities including 50, 75, 100 and 125% of evaporation from the pan were considered as sub-sub plots. The results showed 38% increase of yield for transplanting method in comparison to direct cultivation, but this increase was not significant. Water use efficiency, earliness percentage and lint percentage in transplanting were 14%, 45% and 3.3% higher than direct planting, respectively. The highest yield, water use efficiency, earliness and lint percentage were related to irrigation frequency after 105 mm evaporation of the pan. The treatment of 50% of used water had higher yield, water use efficiency, and lint percentage than other treatments. Therefore, the best treatment was the transplanting method with 105 mm pan evaporation and 50% used water.

Evapotranspiration is the most important part of the hydrological cycle, which plays a key role in water resource management, crop yield simulation, and irrigation scheduling. The purpose of this research was to estimate the reference evapotranspiration using ‘panel-data’ models. Panel-data multivariate analysis endows regression analysis with both spatial and temporal dimensions. This study was carried out using weather data of 9 synoptic stations of Khorasan Razavi during 1971-2000. Data were divided randomly into two sub-sets, 75% for model development and 25% for model evaluation. The panel-data models were developed using the monthly mean air temperature and monthly mean wind speed as inputs in order to estimate monthly reference evapotranspiration. The results indicated that the two-way fixed effects models were superior. The statistical index (RMSE = 9.85, MAE = 7.38 and R2 = 0.99) revealed the effectiveness of this model. In addition, these results were compared with the results of ordinary least squares regression and Hargreaves-Samani equation which showed the superiority of the panel-data models.

Considering the increase in droughts, measuring the capacity of agricultural management institutions to adapt farmers to drought seems necessary. Assessing the performance effectiveness of these organizations to understand the strengths and weaknesses of the organizations and providing solutions to reduce these problems would also be helpfull. This research was conducted in cooperation with the staffs of Agricultural Jihad Organization of Chaharmahal and Bakhtiari province. In this research the dimensions and criteria used in the so called Gupta adaptive capacity wheel were used to conduct a questionnaire survey to measure the organizational capacity regarding drought adaptation. Organizational performance effectiveness was also measured through a parallel survey. Our aim was to investigate the relationship between institutional capacity and the organizational performance effectiveness. Data analysis indicates that more than half of the employees believe that the organization's institutional performance is weak. Analysis of the relationship between institutional capacity and organizational effectiveness through multivariate regression shows that there is a significant relationship between institutional capacity and organizational performance. Finally according to findings, three dimensions of institutional capacity including good governance, leadership and resources explain about 89% of the changes in institutional effectiveness.

In this paper, the effect of inter-basin water transfer on the economic value of water resources has been investigated through a case-study of the Kamal Saleh dam from the Sarband Basin to the central Arak Basin. For this purpose, by using the mathematical model developed in this research, the economic value of agricultural water was investigated without regard to transferred water resources and considering its impact for wheat, barley, alfalfa and corn. The input data for this study was included meteorological and agricultural information, volume of consumed water, wastewater volume, volume of water transfer from Kamal Saleh Dam, as well as information about costs and incomes of the crop year 2015-2016. The results showed that water transfer to Arak city would increase the economic value of agricultural water resources in this city. So, the economic value of water estimated from three methods including weighing the area under cultivation, the volume of water consumption and product income for increasing crop area of corn were increased 10, 7.5 and 9 percentage, respectively . In addition, by increasing crop area of alfalfa the economic value of water estimated from all three methods was increased 2%. Increasing the economic value of water resources can be one of the solutions to sustainable development and food security. However, inter-basin water transfer projects should be implemented with all technical and economic and environmental factors, with emphasis on social and political considerations.

In this study, experiments were carried out in a transparent plexy-glass tank (0.5m*1m*3m) using three different soil textures (fine, heavy and medium). The drippers were installed at 3 different soil depths (surface, 15cm and 30cm). The emitter outflows were considered 2.4, 4 and 6 lit/hr. Also, these experiments were carried out for two continuous and pulse irrigation systems. In pulse irrigation, the pulse cycles were considered 30-30, 20-40 and 40-20 min. In this research, using nonlinear regression model, empirical models were developed to predict the advance velocity of the moisture front at different directions. The parameters of suggested model include emitter discharge, saturated hydraulic conductivity, application time, soil bulk density, emitter installation depth, initial soil moisture content, the ratio of irrigation time to complete period of each cycle and the proportions of sand, silt and clay in the soil. The results of comparison between measured and simulated values of advance velocity indicated that these models were acceptable accuracy in estimating the advance velocity of the wetting front in different directions. The values of the mean absolute error (MAE) and the root mean square error (RMSE) ranged 0.031-0.108 and 0.067-0.275 cm/min, respectively.

In most cases, groundwater in coastal aquifers is the most important source of fresh water. Changes in climate and hydrological variables can have a significant impact on coastal aquifers. In this study, the effect of climate change on the Bandar-e-Gaz coastal aquifer in northern Iran was studied using the scenarios of the fifth report of the IPCC. Also, changes in hydrological variables such as future changes of the sea level, recharge and discharge of the aquifer were also studied using a numerical model. The results indicate that the used numerical model is reliable. An examination of the optimistic scenario review confirms that significant changes will not be made in the future for studied coastal aquifer’s water resources. The results of the pessimistic scenario reveal that in the near future (2040) a relatively limited part of the aquifer will be affected by groundwater decrease, but in the mid future (2070) a large part of the aquifer will face this problem, and a drop of 3 to 7 meters will be experienced. In addition, in the far future (2100) the decrease of groundwater level in the middle parts of the aquifer will be in the range of 10 to 13 meters.

Using additives can improve the mechanical properties of soils of construction projects such as irrigation canals. The materials such as sand, in addition to improving soil conditions, are compatible with the environment. So, in recent decades, the utilization of sandy soils in the construct of irrigation networks has been extended. In this study, the effect of size and amount of sand on the strength characteristics of lime treated soils. In this way, at first, to determine the best soil-lime mixture, the soil was mixed by different amount of lime and unconfined compressive strength of these has been investigated. The highest unconfined compressive strength was achieved by adding 7 percent lime to the soil. Then, a set of tests conducted on coarse (D50= 1.4 mm), medium (D50= 0.45 mm) and fine (D50= 0.22 mm) and by applying 5, 10 and 15 percent of sand to lime-clay mixture in three replicates. The unconfined compressive strength was performed on the specimen at curing time of 7, 14 and 28 days. Results showed that adding 5 percent of coarse sand to clay–lime mixture can increase compressive strength and elasticity module about 13 percent and 16 percent, respectively, on average. In addition, adding medium and fine sands can cause to deteriorate soil’s strength and elasticity module.

Water scarcity is a serious threat for the food security of Iran. Hence, different strategies are considered to save more water and increase water productivity. In this research work, some of the measures that are more pointed out in the country’s high level plans are evaluated based on the concept of "real water savings" and water productivity as well as physical water productivity. The criteria that emphasize on actual evapotranspiration and distinction of water depletion from withdrawal. With this aim, the SWAT model was first applied for the required simulations. However, it was found some deficits in its field scale modeling. So, for some the management scenarios AquaCrop model was also used. The evaluated measures include: deficit irrigation (scenario 20, 40 and 50 percent), substitution of drip irrigation with surface irrigations and greenhouse cultivation. To show the methodology, the Marvdasht and Kharame subbasins- located in Fars province, are selected. The results showed that the deficit irrigation at its highest rate (i.e. 50%) saves water up to 12%. While, implementing drip irrigation led to increase 8.3% in water consumption. Similarly, greenhouse can result up to 24% reduction in evapotranspiration, which has the highest capacity for real water saving. Notably, the water productivity does not change significantly, while applying deficit irrigation and increasing irrigation efficiency. But, it is physical water productivity that increases that cannot be due decrease in water depletion. The modeling framework of this research was found suitable for the field and basin scales assessments. It considers various aspects of water balance and water productivity components. So, it is recommended to be considered for similar research works regarding water saving and water productivity policies.

In many areas of Iran, there is no detailed information on the amount of erosion, sediment transport and sedimentation of rivers, and in many cases, there are many difference between measurements. Due to the fact that the flow regime and consequently the sediment regime in the watersheds are not constant, the prediction of sediment rate helps to estimate the sediment accumulated behind the structures, specially the dams, and determine the dead volume of reservoirs in the future months, and by adopting timely arrangements facilitate the deposition management to a certain extent. In this research, three optimization algorithms including Genetic Algorithm (GA), Gray Wolf Optimizer (GWO) and Election Algorithm (EA) were used to predict the suspended sediment load of the rivers. In order to evaluate the performance of the algorithms, three statistics consists of R2, RMSE and NSE were used. The suspended sediment load of sedimentary station located in the Zarrineh-Rood river during the 2005-2015 are used as a case study. The results show GWO algorithm with values R2=0.96, RMSE=0.022 and NSE=0.74 has a very high accuracy compared to other algorithms used.

Water scarcity is considered as one of the important factors affecting the production of agricultural products. Using crop management models such as the AquaCrop model can be a useful tool for reviewing the options and the ability to examine them in different situations. This study was conducted to evaluate the AquaCrop model's ability to determine the irrigation time of sugarcane plant and it’s monitoring with water stress index in 2017 in cultivars and cultivars of sugarcane arranger cultivars in a R7-11 field with a total area of 25 hectares and a plant (new crop) Variety CP69-1062 was performed in south Ahwaz. The calibration was done to determine the accuracy of the model at the time of irrigation of the sugarcane plant, including an examination of the water stress index (CWSI) with a reddened thermometer. This calibration showed that the AquaCrop model has a relatively high simulation ability in determining the cannabis irrigation time. The statistical analysis of the accuracy of the model in predicting the irrigation time of the field with the actual field conditions was RMSE = 2.0 %, d = 1.0 and CRM= 0.006. The irrigation scheduling of R7-11 farm with AquaCrop model was carried out with a total irrigation interval of 16.6 rounds (from April to October 2017), the number of irrigation intervals with the number of irrigation intervals in plantations of CP69-1062 plant cultivars and dental industry Compared with the total irrigation intervals in the farms of 20.8 rounds, the Khazaee was compared, it is observed that a R7-11 farm saved a quarter of the irrigation round in that year. The yield of this field yielded 128 tons per hectare and the average yield of planted plots of CP69-1062 varieties and cultivars were about 106.63 tons per hectare. The quality of the R7-11 sugarcane syrup contains purity (PTY %) and the percentage of white sugar (RS %) of PTY = 90.0 % RS = 11.1 % and the average plant plantation varieties of CP69-1062 cultivars and cultivars, PTY = 88.6 % and RS = 10.8 % were obtained. The results of this study showed that considering the AquaCrop model has high accuracy, the use of this method to determine the irrigation time compared to the current method (crop log) that is common in sugar cane companies in Khuzestan, both in terms of cost and in terms of its use in research projects.

Freshwater crisis and soil salinity are the most important factors that limiting agriculture in arid areas. In these conditions, cultivation of medicinal plants with considering environmental aspects can be an intelligence strategy for these areas. For this purpose, a field experiment with four treatments and three replications was conducted in randomized complete blocks design in Zahak city during 2016-2017. The treatments were consisted of full irrigation with fresh water (F.FI), partial root zone drying with fresh water (F.PRD), partial root zone drying with saline water (S.PRD) and partial root zone drying with saline and fresh water (SF.PRD). The highest values of plant height (46.1 cm), number of umbel per plant (42), number of branches per plant (10), 1000-seed weight (0.86 gr) and seed yield (293 kg ha-1) were observed in F.FI. There were non-significant differences between F.PRD, FI and SF.PRD in most traits. Results illustrated that application of PRD with alternate fresh and saline water was the best option for decreasing fresh water usage in arid climate of Sistan region.

The growing demand for agricultural products and the reduction of access to conventional water resources have highlighted the need for proper management of water resources in agricultural sector. On the other hand, measuring and acquiring field data problems make it necessary to employ efficient models that can accurately predict yield and sensitivity analysis of yield over various parameters. Therefore, in this research, the effects of different parameters on the yield of forage maize in the country have been investigated and the effectiveness of the artificial neural network models to predict forage maize yield has been evaluated. The parameters of irrigation water salinity, soil salinity, plant growth period, water consumption and number of irrigation of 104 farms in 8 provinces that were collected during field studies were used to develop models in the artificial neural network. Also, by estimating the water requirements of selected farms, the expected yield was estimated using the optimal selected model and compared with the measured yield in the farms. The results showed that the artificial neural network model with two hidden layers and the final structure of 1-15-19-5 can accurately estimate forage maize yield (R2=0.85). The results of the sensitivity analysis of the selected optimal model showed that the parameters of irrigation events and plant growth period were the most effective and least effective parameters on the forage maize yield, respectively. Also, the results of the modeling showed that there is a gap between the measured yield in the farms and the expected yield, and if the full irrigation requirement is applied, the forage maize yield in the studied areas can be increased by an average of 12.5 tons per hectare.

In arid and semi-arid regions, salinity is a serious and chronic problem for agriculture. Due to the improved methods of irrigation and mechanization this methods to increase water use efficiency and enhance the uniformity of water distribution in the field, is very important. In order to investigate the effect various source of saline water as well as different value of irrigation on characteristics of greenhouse cucumber, a field experiment was carried out during 2018 growing seasons at an experimental farm in Jiroft territory of Kerman province. The treatments were laid out in Randomized Complete Block Design with three replications. The treatments were comprised of four levels of irrigation including 15, 30, 45 and 60 mm evaporation for class A pan and three salinity of irrigation including 0.9, 2.6 and 7.5 dS.m-1 as the main and sub plot respectively. The results showed that in comparison to 30 and 15 evapotranspiration for class A pan, parsimony of water usage equal 370 m3 ha-1 achieved. Moreover yield, high plant, weight fruit and number of fruit per plant decreased 6.3, 8.1, 5.2 and 8.1 percent respectively but water productivity increased 5.9 percent. Also, In comparison to 0.9 and 2.6 dS.m-1 salinity of irrigation, yield, high plant, weight fruit, number of fruit per plant and water productivity decreased 7.1, 5.6, 5.2, 6.1 and 7.1 percent respectively.

Dam rule curves should be derived using operation models and considering reservoir storage as well as input flows, which results in better management of reservoir water. In this paper rule curves of Doroudzan dam in Fars province, has been derived, using standard operating policy (SOP), hedging rules and linear programming. The objective function is water deficit minimization during 88-92. Standard operating policies result in severe water shortage. To mitigate the severe water shortage in SOP; the hedging policy has been used, which accept some present delivery deficit to reduce greater shortage in the future. The Genetic algorithm has been used to find the hedging optimal factors. Finally, the results of SOP and hedging-GA are compared with a model linear programming based on hedging rules model. Total shortage in hedging-GA is 84.19 MCM, hedging-LP is 219.5 MCM and in SOP is 216.57 MCM. The GA-hedging model by supplying 88.33% of demands control the amount of shortage as well as the shortage severity. In addition, the average reservoir storage is the biggest amount among the three methods. Comparison of the mentioned models using assessment criteria including time reliability, volume reliability and vulnerability shows the hedging-GA model is less vulnerable and more reliable; therefor this model performance is better than the two other models.

Due to an increase in impermeable areas in cities, the runoff volume increases dramatically, causing overflow of runoff and frequent problems in the city. In the present study, the 10th district of the municipality of Mashhad that is known as Chehel Bazeh Golestan was evaluated. In this regard, Arc Map and ASSA software were used for modeling. The basin was modelled according to the existing conditions by using AutoCAD and Arc Map. The geometric parameters of the basin including area of the sub-basins, length of the canals, slope and other characteristics were calculated by using Arc Map. For rainfall distribution, uniform rainfall pattern and alternative block method were used. For the return period of 2 and 5 years, the adequacy of system for runoff was investigated. Results showed that rainfall pattern plays an important role in the basin runoff. The alternative block method for the return period of 2 years, resulted in 33% increase in runoff relative to the uniform rainfall method. In the alternative block method, the outflow runoff of the basin was 29% more than the uniform rainfall method, and the outflow volume increased by 17%. In general, in urban areas due to variation in land use and different basins, uniform rainfall method, due to consideration of geometric parameters of basins, offers better results than alternative block method.

Groundwater as one of the valuable resources all over the world is unfortunately facing a great decline of aquifer level during past decades cused by its overexploitation beside the decrease of precipitation. This reduction is more in arid and semi-arid climatic zones where the most part of irrigation requirement is supplied through wells. Therefore, the monitoring of the spatio-temporal variation of aquifer water table would be necessary. In this study, shallow and deep aquifers of Golestan province were considered as case study. Non-parametric tests including Mann-Kendall, Sen’s slope and Pitite were used for analysis of recorded time series between years of 1990 to 2016 in 277 piezometric stations. The results were interpolated in GIS enviroment. In this study, the pattern and trends of groundwater level data were investigated. Results showed the aquifer groundwater level has a decreasing trend in most of the areas but in shallow aquifers along with the decreasing trend, an increasing trend has been observed in some places. In shallow aquifers, the slope of the trend line is in accordance with groundwater flow direction but there is no regular pattern in deep aquifer. The decreasing trendline of groundwater variation in deep aquifer is more than 8 percent. This aquifer has worst conditions about groundwater depletion than the shallow aquifer and this may be due to overexploitation of the aquifer and the failure of fast replacement. Also result showed that all three nonparametric tests were highlighted these variations and are following the same pattern.

Unsaturated hydraulic conductivity (K(θ)) is proportional to volumetric water content in vadose zone and the obtained K(θ) curve is crucial for modeling the soil water movement. Numerous theories and models have been recently proposed regarding the estimation of K(θ) that despite improving model predictions, each has a disadvantage of its own. The critical path analysis from percolation theory attempts to improve the prediction of K(θ) by simplifying the complex geometry of the porous medium. In addition, the recently developed Peters-Durner-Iden model (PDI) has shown high potential for prediction of K(θ). In this research, both percolation theory and PDI models are evaluated. Also, by using Monte Carlo- Markov chain method, the uncertainty of the simulated parameters is assessed. In this study, the Hybrid-Evolution Monte Carlo-Markov chain algorithm has been utilized, that employs adaptive metropolis, differential-evolution, and Snooker update algorithms, which minimizes the number of iterations required to search parametric space. Goodness of fit measures shows higher results for prediction of K(θ) by percolation theory and in every case except for a single soil, the Nash–Sutcliffe criterion was higher than 0.9. In addition, the number of parameters required for the PDI model is more than percolation theory, which leads to an increase in parameter- associated uncertainty. It is also discussed that it is possible to reduce the number of parameters required by PDI model by applying several constraints. But this method is not applicable to all soil textures. Comparison of the convergence rate of the two models showed that parameters of PDI model in all cases require close to 300 iterations to converge while, percolation theory requires up to 2000 iterations to converge. Therefore, the results indicate that the percolation theory with fewer number of parameters can provide more accurate and reliable estimates of K(θ) and water retention.

AquaCrop model simulates biomass yield under deficit irrigation management. This model developed by FAO and requires less input data than other similar models. One of the input data of this model is the normalized water productivity (wp*) that should be known for each plant. This parameter for the radish plant, which is part of the C3 plant, has not yet been determined. Therefore, the first objective of this study is to determine it for Pakdasht area and its second objective is to analyze the sensitivity of the Aquacrop model to the input data of reference evapotranspiration (ETo), Wp*, initial canopy cover (CCo) and maximum canopy cover(ccx). This research was carried out in the research center of Abourayhan Campus, University of Tehran in Pakdasht District during 2018 crop year. According to the results of this study, normalized water productivity of radish was determined to be 11.3 g / m2. The results of sensitivity analysis showed that the AquaCrop model has the most sensitivity to the normalized water productivity parameter for full irrigation conditions, in which the sensitivity coefficient was estimated to be 0.88. Under deficit condition, the model is most sensitive to the ETo parameter, and the less irrigation is more severe, the sensitivity coefficient increases. The sensitivity coefficient for 60% deficit irrigation was -10.99.