مجله پژوهش آب ایران
پیاپی 42 (پاییز 1400)

Iron is one of the elements whose total amount in Iranian soils is significant. This element is nutritionally essential for the plant, but too much of it can cause toxic conditions. It is noteworthy that wetland conditions affect the solubility of this metal and its high content can also cause clogging of drains. Soil pH is the most important factor affecting the absorption of iron and in anaerobic and acidic conditions, the amount of iron increases to toxicity. Increasing the solubility of iron due to physicochemical interactions of wetlands not only increases the absorption of iron as a micronutrient and essential element for the plant, but also affects its leaching. This study was conducted to investigate the effect of controlled drainage on iron concentration in drainage water and its uptake by maize.This study was conducted in two cropping years 2018 and 2019 (spring and autumn cultivation) in the experimental farm of Shahid Chamran University of Ahvaz at 400 m2 (length and width equal to 20 m) was done. In this study, single-cross 647 hybrid maize was used in spring planting and single-cross 704 in autumn planting. For this purpose, factorial experiment was performed based on a completely randomized design with four treatments and three replications in two planting seasons; i.e. spring and fall on the experimental fields. The first treatment was free drainage (FD), the second treatment was variable water table (CD-Var) (with a fixed distance from the water table to the root development area), the third treatment was water table stabilization at a depth of 50 cm (CD50) and the fourth treatment was water table stabilization at depth 50 cm and release after 24 hours after irrigation (CD-In). Controlled drainage experiments were performed using cylindrical lysimeters made of corrugated polyethylene with a diameter of 80 cm and a height of 120 cm with an underground drainage system.According to results in two planting seasons the controlled drainage had a significant effect on the concentration of iron in drainage water, iron uptake by maize and the yield of maize components at the level of one percent. The highest concentration of iron in drainage water in spring and autumn cultivations was related to controlled drainage treatment with variable water table (CD-Var) of 1.92 and 1.56 mg / l respectively, and the lowest concentration of iron in drainage water was related to free drainage treatment (FD) equal to 0.83 and 0.8 mg / l were obtained in spring and autumn cultivations respectively. The results showed that the concentration of iron in the grain was higher than the stem and leaf. The highest concentration of iron in grain for CD-Var treatment in spring and autumn cultivation was 103 and 80 mg / kg, respectively, and the lowest concentration of iron in grain for FD treatment in spring and autumn cultivation was 32 mg / kg and 30 mg / kg, respectively.On the other hand, controlled drainage increased crop yield in CD-Var treatment compared to other treatments. 1000-seed weight in CD-Var treatment in spring and autumn cultivation were 282 and 313 g, respectively, and these values were 207 and 222 g for FD treatment, respectively. Also, iron concentration in soil, seeds, stems and leaves in CD-Var treatment was higher than other treatments. The results showed that controlled drainage increases plant yield and water use efficiency. Also, in terms of water use efficiency, controlled drainage between different treatments has created a significant difference at the level of five percent. Controlled drainage has significantly increased water use efficiency in different treatments. The highest effect on water use efficiency was related to CD-Var treatment at 9.44 and 10.69 kg / ha and the lowest effect was related to FD treatment at 7.37 and 8.27 kg / ha for spring and autumn cultivation, respectively. but on the other hand, based on the results of iron concentration in the drainage water and its increasing trend, there is the potential for ochre production in CD-Var and CD50 treatments. In CD-In treatment, in terms of ochre production potential, it was in the low potential range. In free drainage treatment, the concentration of iron in the drain in both seasons and during the growth period was less than one milligram per liter and can be neglected in terms of the potential for ochre production.

Using of drip irrigation systems in order to manage water consumption and increase irrigation water productivity is important in the absence of water resources. As water scarcity is a limiting factor in agricultural production, an accurate irrigation scheduling and management is necessary to increase water productivity and crop yield. Recently, a new technology called a pulsed management has been used in drip irrigation systems. Pulse irrigation management consists of a series of irrigation cycles with On-Off phases that these cycles will continue until the entire water required by the plant enters to the field. In order to investigate the effect of deficit irrigation on yield and water productivity of silage maize under pulsed and continuous management in a drip irrigation system, an experiment in the form of split strip plots based on a randomized complete block design with three replications was implemented in Varamin region in 2019. The aim of this study was to compare the water productivity and yield of silage maize under a surface drip irrigation system with pulsed and continuous flow.

Three irrigation levels include two deficit irrigation treatment and one full irrigation treatment were examined under two pulsed and continuous irrigation management. The main factor included three irrigation levels, applying 100, 80 and 60% of crop water requirement (W1, W2 and W3, respectively) and the sub-factor included two drip irrigation managements, pulsed (P) and continuous (C) in a drip irrigation system. The silage maize hybrid ZP 606 cultivar with a comparative maturity of 93 to 95 days was sowed at a depth of 5 cm with Pneumatic seeding machine. The replications were separated by 2 m to ensure that the treatments in plots were independent to each other. The linear plant density was 12.4 plants m-1, which is equivalent to 124,000 plants per ha. The space between plants was 11.5 cm. In full irrigation treatment, irrigation depth was determined based on bringing the soil moisture to the field capacity and other treatments received a coefficient of that treatment. The soil moisture content was measured using the PR2 profile probe instrument (Delta-T Devices, Cambridge, UK) that was calibrated in the field experiment. The access tubes of the profile probe installed in the middle of the maize twin rows beneath the emitter up to the 100 cm depth of the soil. The plant height, biological yield were measured at the end of the growing season and then water productivity was calculated. The statistical analysis of the results was done using SAS software to determine the best combination of factors for optimizing water productivity and crop yield.

The amount of irrigation water used in W1, W2 and W3 treatments was 405, 340, 275 mm, respectively. The results showed that the application of different irrigation levels had a significant effect on plant growth indicators, crop yield and water productivity. The effect of irrigation management on these parameters was also significant. Based on the obtained results, the highest biological yield of silage maize was related to PW1 treatment (25 ton/ha) and the highest irrigation water productivity was obtained in PW2 treatment (6.72 kg/m3) with a 25% and 35% increase compared to continuous full irrigation treatment, respectively. The application of pulsed management in W2 irrigation treatment (applying 80% of crop water requirement) compared to full irrigation treatment with continuous management, water productivity increased by 34.93%. The results also showed that in intensive deficit irrigation treatment, W3 (applying 60% of crop water requirement) applying pulsed management had an adverse effect on product growth and yield parameters, so that in this treatment, biological yield declined by 23.28% compared to continuous management treatment. The highest plant height was 285 cm related to PW1 treatment that has 4.5% increase compared to CW1 treatment. The overall results of this study showed that by applying pulsed management in deficit irrigation conditions, applying 80% of the crop water requirement while saving water consumption, the water productivity can be increased by about 35% without significant reduction in crop yield. The lowest plant height was 172 cm in PW3 treatment. According to the statistical analysis of irrigation water productivity, in areas with similar climatic condition and limited water resources in order to save 20% of irrigation water, PW2 treatment was recommended in silage maize planting.

Increasing demand for water has challenged governments to manage water resources by optimizing and designing highly efficient hydraulic systems. One common water-management device is the weir which is used to modify the water-flow within rivers. Existing weirs are not typically responsive to water demand. Consequently, it would be advantageous if the water supply from these structures could be modified to meet fluctuating water demand. Therefore, new structures could replace existing structures or modifications could be made to current weirs to achieve this desired control. Candidate changes could include an extension of the weir crown or an opening up of the weir body to modify the flow. When the flow can pass over and under the structure, one of the proposed options is a combined culvert-weir, which also increases the sediment and flow rate. Choosing the appropriate overflow to achieve this goal is very important. In this research, the piano key weir has been used as the overflow of this combined structure due to its high performance. The innovative shape of a non-rectilinear weir, known as the Piano-Key weir PKW, increases the total effective crest length, escalating the discharge capacity of the weir. A PKW is a modified form of a labyrinth weir with the specific geometrical characteristics including inlet and outlet overhangs or inclined inlet and outlet keys floors, forming a new set of variables.

The experiments have been performed in hydraulic laboratory of Shahid Ashrafi Esfahani University. The tests were conducted in a rectangular channel with 10 m long, 0.6 m wide, and 0.75 m high. Models were built with galvanized sheet with 0.9 mm thickness. Laboratory models of the combined culvert-weir were examined by considering the varied height and length of the overflow, as well as the different openings for culverts. In addition, the performance of the culvert and piano key weir was investigated and compared with the combined structure. Experiments had been done in free flow conditions and in discharge range of 5 to 50 lit/s, for piano key weirs, culverts and combined culvert-weir structures. The geometry parameters of models are shown in Table (1).

The results indicated that in the PKW the discharge 25% and 12.5% is increased with %50 and 63% increasing in height and width of the weir respectively. Thus, the effect of the height on increasing the discharge of the weir is more considerable. In combined structures the effects of culvert opening are more than weir height. The results show that for a specific head, the discharge of combined structure is greater than the discharge of weir and culvert and the efficiency of combined structure is approximately 10% more than culvert and weir.The results showed that in piano key weirs, the discharge coefficient decreases with the dimensionless ratio of head to the weir height and in the combined structure, this trend is increasing. Therefore, in situations where the flow rate is high and it is not possible to use a high piano key weir, a combined culvert-weir is a good option.

Agro-hydrological models play an important role in water resource management. However, their predictions always suffer from various sources of uncertainty, including model structures, parameters, and input and output data. Model structural uncertainty is caused by the fact that the model cannot perfectly represent the natural processes involved in the studied system. Parameter uncertainty indicates that many model parameters are not directly measurable or can only be obtained with unknown errors. Measurement uncertainty in input and output data is due to unknown measurement errors and incommensurability errors. Hence, it is important to assess the degree of uncertainty involved in agro-hydrologic modeling. The generalized likelihood uncertainty estimation (GLUE) method has been widely used for uncertainty analysis in hydrologic modeling because of its simplicity, ease of implementation, and less strict statistical assumptions about model errors. In GLUE, parameter uncertainty accounts for all sources of the model uncertainty. The drawback of the GLUE is its prohibitive computational burden imposed by its random sampling strategy, which hinders the efficient application of the method. In this study, a hybrid high-dimensional uncertainty analysis method was developed, combining GLUE with an evolutionary optimization algorithm, Unified Particle Swarm Optimization (UPSO), to improve the computational efficiency of the GLUE framework. UPSO is a modification of Particle Swarm Optimization (PSO) that aggregates its local and global variants, combining their exploration and exploitation capabilities without additional objective function evaluations. The hybrid GLUE-UPSO framework was used for uncertainty analysis of SWAP distributed sub-daily agro-hydrological modeling for a sugarcane farming system with combinational free/controlled subsurface drainage management.

The source code of the SWAP model was modified and extended to consider the duration of the irrigation events, simulation of sub-daily reference evapotranspiration, sub-daily precipitation interception, ratooning, and implementation of subsurface controlled drainage during the simulation period. The GLUE-UPSO framework was coded in FORTRAN and C++ and integrated into SWAP source code. The developed framework was applied to a dataset collected from a field with a combinational free/controlled (70-cm depth) subsurface drainage management located at Shoaybiyeh Sugarcane Agro-industrial company farms, Khuzestan province, Iran. The simulation was performed from 2010-07-19 to 2011-12-11 (481 days) for planted sugarcane (CP48-103 cultivar). A soil profile of 550 cm depth (depth of impermeable layer) was specified during simulations. The soil profile was divided into two layers. To consider the heterogeneity of irrigation scheduling at different parts of the studied field, the field area ( 21 ha) was divided into ten homogeneous simulation units, termed as hydrotopes. Hydrotopes have similar agro-hydrological properties except for irrigation scheduling. The model was calibrated, using the measured soil moisture profile, soil solute concentration profile, groundwater level, subsurface drainage outflow, drainage outflow salinity, Leaf Area Index (LAI), cane yield, and sucrose yield in a parallel manner. The weighted average of simulated values derived for each hydrotopes was compared with the corresponding measured data. Totally, 45 parameters were estimated through the GLUE-UPSO framework. The accuracy of the model in calibration and validation stages was evaluated, normalized root mean square error NRMSE and Nash-Sutcliffe model efficiency coefficient EF. The behavioral parameters were identified, using NRMSE > 0.2 for solute transport (soil water solute concentration and drainage outflow salinity) and EF > 0.7 for hydrological (soil water content, water table level, and drainage outflow) and biophysical (cane yield, sucrose yield, and LAI) simulations. For each parameter set, the objective function values were used as the likelihood measure to calculate the corresponding likelihood weights. The 95% prediction uncertainty (95PPU) bands were calculated at the 2.5% and 97.5% levels of the cumulative posterior distribution (realized from the weighted behavioral parameter sets) of the simulated state/flux variables.

The results revealed a significant nonuniqueness of the calibrated parameters and the necessity of an uncertainty assessment for the SWAP simulations. Strong parameter correlations highlighted the need for calibration of the model parameters against diverse calibration data in a simultaneous manner. The 95% prediction uncertainty bands obtained for the model's hydrology (soil water content, water table level, sub-surface drainage outflow), solute transport (soil water solute concentration and sub-surface drainage outflow salinity), and biophysical (leaf area index, cane, and sucrose dry yield) components enveloped 41-87%, 18-67%, and 75-100% of the corresponding total observed data (including both calibration and validation datasets), respectively, with a r-factor (the ratio of the average thickness of the 95PPU band to the standard deviation of the corresponding measured variable) of 0.71-1.14, 0.33-1.14, and 0.84-0.98. The results indicated that the hybrid GLUE-UPSO framework offers an efficient alternative to provide traditional calibrated parameters as well as uncertainty analysis of computationally expensive hydrologic models.

One of the useful techniques in flood management planning is identifying flood areas and calculating the flood potential of the basins. However, due to the environmental complexities, this identification has many challenges. Flood prioritization of a basin is the classification of sub-basins of a basin according to the role of each of them in producing the peak discharge of flood produced at the outlet of the basin. There is a wide range of methods for estimating runoff from the basin, such as the use of observational data, experimental and statistical techniques for estimating river discharge, more commonly known as rainfall runoff models. Deriving flood prone areas and identifying flood potential of basins is one of the crucial issues in flood control planning projects. In this way, it will be cleared that which of sub-basins in a whole basin are in priority of implementing flood control scenarios. Prioritization of basin area in term of flood generation is the procedure of dividing and classifying sub-basins based upon their contribution in generating the peak discharge of flood hydrograph. In the other words, the sub-basin with the most contribution in generating the peak discharge, will be categorized in the first flood prone priority.

In recent years, for the flooding status of watersheds, the division of the basin into a number of sub-basins and flood tracking in each sub-basin and then in the main waterway network has been used. With this method, flood-prone and critical sub-basins are identified according to their share in flood production of the entire basin. In the individual sub-basin removal method, first the total discharge flow of the basin is calculated and then in each step, each sub-basin is removed from the simulation process and the peak discharge is calculated again; Then, the flooding index of the sub-basin (F) is calculated and the priority of the said sub-basin in the production of total peak discharge is ranked. Single successive sub-basin elimination method (SSSEM) is one of widely accepted methods in this field. Considering the wide variation of temporal pattern and amount of precipitation, by combining GIS technique and HEC-HMS model, the efficiency of SSSEM method in Lar basin of Zahedan was assessed in this research. After deriving the optimum number of sub-basins, calibration and validation of the simulator model was carried out and flood prone priority method performed using different duration, return period and temporal pattern of precipitation. It should be noted that in previous studies, the sensitivity of the individual removal method in extracting flooding of sub-basins to the height and temporal pattern of precipitation has not been investigated and in this study we have tried to address the sensitivity of this method to the mentioned factors. In this study, different return periods were considered as a criterion for precipitation height and SCS standard time patterns and the dominant regional precipitation pattern were considered as criteria for time pattern change. Meteorological data used in this study include rainfall and hourly runoff; Collected from climatology, rain gauge and hydrometric stations over a period of 22 years (from 1997 to 2020).

According to the obtained results for determining the flooding potential and ranking of sub-basins by repeated method of individual sub-basin removal, it is observed that the individual removal method does not show sensitivity to rainfall time pattern, its continuation rate and return period. At a continuum of 1.5 times the concentration time, the sensitivity of this method to the time pattern of precipitation is observed and with increasing the return period, the anomaly in the ranking according to different patterns increases. There is a sensitivity to changes in the precipitation time pattern and return period at twice the concentration time, but the amount of anomaly is less than before. It should be noted that regardless of the rank of each sub-basin in terms of flood production and its effect on the peak hydrograph discharge, it should be examined what effect the application of flood control scenarios in that basin will have on the damage caused downstream of the city. In other words, in addition to the peak discharge that is the result of this study, other components of the flood, such as its volume, time corresponding to the peak discharge and also the response of the urban drainage system will be effective in the occurrence and severity of destructive flood effects; It may not be the first sub-basin in flood production, but the dynamics of its flood production in interaction with the city's drainage system will impose far more destructive effects, both economically and human losses in the city. Therefore, in order to complete the study and to evaluate the effectiveness of different flood risk scenarios, there is a need for a hydraulic study of rising water levels in different parts of the city, taking into account the sensitivity of each point in terms of economic and population density.

Among the regulator structures used in water projects, weirs have remarkable applications like measuring flow, maintaining water level, controlling sediment transport, and managing variable water inflows. Weirs can be classified on the weir axis direction as a normal, side, or a labyrinth weir. labyrinth weirs are hydraulic structures used to regulate water levels and control flow in reservoirs of dams, canals and rivers.The discharge coefficient in the weirs is directly proportional to the crest length of weir. If the width of the channel or reservoir where the weir made is limited, one of the ways to increase the capacity is to increase the crest length of weir by zigzagging the weir in the plan. Due to their complex geometry labyrinth weirs are expensive to build. Therefore, in laboratory studies, high cost is one of the reasons that has made it difficult to investigate this type of weir comprehensively. Numerical methods are a very good option for hydraulic analysis of labyrinth weirs hydraulic. The history of the construction of labyrinth weirs goes back to before the year 1920 (Darvas, 1971). labyrinth weirs were first investigated by Gentellini )1940(. Vahab nezhad (2017) studied the changes in discharge coefficient for the three angles of 15, 18 and 23 degrees. Zamiri, et al. (2016) showed that increasing the thickness of the labyrinth weir wall increases the depth and velocity of the flow and ultimately reduces the discharge coefficient. The results showed that the discharge coefficient increases with increasing the weir angle, because as the weir angle increases, the weir length decreases and the discharge coefficient increase.In this study, the weir performance of a trapezoidal labyrinth with different angles (α) was investigated. For this purpose, labyrinth weir modeling was performed with three angles of 15, 23 and 30 degrees for two crest length of 5 and 7 cm and three heights of 10, 14 and 18 cm. The geometry of the weirs was created in the Inventor software and simulation was performed in Flow3D software. In order to validate the simulation and adjust the software parameters, valid laboratory data were used and the results of the model were in good agreement with the results of the laboratory data. For this purpose, the discharge coefficient of numerical models (Cd (CFD)) and laboratory (Cd (EXP)) for different values of water to overflow ratio (h / p) were compared and the error value was calculated. The highest error rate is 5.88 and the lowest is zero. In fact, with increasing the ratio (h/p) the error rate has increased, but this increase is also acceptable and the results show that Flow3D software has a very good ability to simulate labyrinth weir. Flow field study was performed with different turbulence models in Flow3D software using laboratory data. The RNG model was used in all simulations. To mesh the model, the channel was divided into three parts: initial, middle and end. The dimensions of the cube of the initial and final parts are 1 cm and the middle part is 5 mm.Analysis of the results showed that increasing the weir angle in a fixed crest length, increases the discharge coefficient (cd). The inverse relationship between the relative hydraulic load (h/p) and the discharge coefficient was also determined. Increasing the crest length of the weir by 2 cm, the trend of increasing the discharge coefficient due to increasing the weir angle, decreased by 9%. Also, increasing the angle 15 degrees, the trend of increasing the discharge coefficient due to increasing the crest length, decreased by 5%. This means that at higher angles, the effect of increasing the crest length on the discharge coefficient decreased and during shorter crest length, the effect of increasing the angle on discharge coefficient increased. Due to the direct relationship between the discharge coefficient and the average flow velocity, simultaneous increase crest length and weir angle increased the average flow velocity by 4 times at the beginning of the channel floor impact. In cases where the purpose of the study is to increase the discharge coefficient by increasing the angle and length of the weir crest, it should be noted that the effect of increasing the angle and length of the weir crest is more noticeable at low altitudes, So that with increasing the height of the weir this amount decreases.

Water scarcity is a global and regional concern and requires a global and regional perspective. The water shortage crisis that the world and consequently Iran is experiencing shows the importance of water resources and the optimal use of those resources. Therefore, water supply is of special importance for the people of the world and different economic sectors, and any disruption in its process can lead to social and economic problems. Most policymakers and researchers believe that water scarcity and its effects on developing and developed countries as a global threat. It is clear that the issue of water has become an area of international cooperation. Concerns about water scarcity and water management problems in different parts of the world have made water issues the focus of many international and non-governmental organizations (NGO). According to studies, the formation of regional water markets is one of the methods of water resources management. To reach regional water markets, one of the effective tools is to create a suitable platform for economic convergence. Convergence is generally centered on gravity models. In the structure of these models, the basic condition for achieving economic convergence is convergence in production and productivity. This study has dealt with the most important variables affecting economic convergence through the productivity channel. Because distance is important in the formation of regional water markets, Iran has been selected and studied for convergence analysis with neighboring countries (Pakistan, Turkey, Russia, Kazakhstan, UAE, Armenia, Azerbaijan, Bahrain, Kuwait, Oman, Qatar, Saudi Arabia). Also, in order to see the effect of productivity shocks in the best possible way, a dynamic computable general equilibrium model has been used. The data required to simulate the scenario presented in this study are taken from the ninth version of the GTAP database. This version includes the world with 140 regions or countries, including Iran and 57 economic sectors. 57 parts of the model have been changed to 13 parts and 5 production factors to 8 production factors, which are as follows. Sectors include: Agriculture, Other Agriculture, Livestock, Forestry, Fisheries, Coal, Oil, Gas, Industry, Petrochemicals, Electricity, Water and Services. Production factors include: water, land, rain fed land, pasture land, skilled labor, unskilled labor, capital and natural resources. The characteristic of computable general equilibrium models is that it different scenarios can be evaluated and examined in the context of general equilibrium. For the productivity variable, the concept of total productivity of production factors is used, which is one of the factors affecting production and convergence. The results showed that positive productivity shocks have led to the expansion of foreign trade between Iran and neighboring countries. In practice, the expansion of trade can be considered as a factor for economic convergence between Iran and neighboring countries. Also, the productivity shock, in addition to slowly increasing economic prosperity, has also led to a kind of stability and stability in economic growth. Therefore, if productivity is an inevitable movement in the economic use of water resources, it can lead to economic convergence with an emphasis on water trade. Also, the result of the dynamic model shows a positive outlook for Iran and neighboring countries. Since economic convergence is a precondition for reaching regional water markets, Therefore, convergence with border countries is a suitable strategy for the Iranian economy to form regional water markets. It is natural that the formation of regional water markets can provide a good opportunity to deal with the crisis in water resources and also increase prosperity and stability in economic growth. So that the effect of the welfare change scenario shows that this index in Iran will increase from 31952.9 in 2023 to 2793848 in 2030 and this shows the positive effect of the regional water market on welfare. So that the effect of the welfare change scenario shows that this index in Iran will increase from 31952.9 in 2023 to 2793848 in 2030 and this shows the positive effect of the regional water market on welfare. According to the literature on gravity models, total value added, which constitutes GDP, is the most important variable affecting the convergence. Therefore, the effect of productivity shock on GDP indicates the necessary potential for economic convergence. The result of the dynamic model showed that the effect of positive productivity momentum on the change in the value of GDP is positive. It should be noted that, in the long run, by 2030, Iran and neighboring countries will reach a relative stability in terms of GDP value. Thus, the flow of productivity in the long run can provide stable conditions for GDP. Accordingly, the appropriate strategy for the Iranian economy in the formation of regional water markets can be considered as convergence with neighboring countries, which will also provide a good opportunity to deal with the crisis in water resources.

Water and nitrogen fertilizer are the most important agricultural inputs in the production of tea leaves and shoots as yield. In some months (mid-June to early September), the amount of rainfall is less than the water requirement of tea plants and the amount and quality of the product due to water shortage stress is greatly reduced, which threatens the livelihood of farmers and the region's economy. Therefore, supplying the required water of the tea plant by using supplementary irrigation and correct principles of operation is the most important issue in increasing the quantity, quality and marketability of the tea produced and its economic efficiency. The use of conventional fertilizer application in the region, ie fertilizing mixed with soil in rainfed (without irrigation) and irrigated (sprinkler irrigation) fields had high losses and low efficiency. Reports show that more than 60% of tea plantations in Guilan and Mazandaran provinces are located in highlands and sloplands regions. Currently, sprinkler irrigation methods are used to irrigate less than 5% of the total tea growing regions (about 20,000 ha), while production in other regions is entirely dependent on precipitation. Technical limitations and restrictions related to the design and implementation of sprinkler irrigation methods in these regions are the main reasons for the underdevelopment of irrigated lands in tea growing regions. This issue and the lack of access to reliable water resources in these regions, highlights the importance of using drip irrigation in tea plantations. Therefore, the main challenge in this situation is the implementation and development of effective and low-cost irrigation methods that have high water productivity and are cost-effective for farmers.In order to optimize water and fertilizer use in drip irrigation system in tea fields, a field experiment was conducted in 2017-2018 in tea plantation in Bazkiagoorab region, Lahijan (Guilan province). The experiment was conducted as split plots in a randomized complete block design with two factors of irrigation water and nitrogen fertilizer in three replications. Fertilizer was considered as main factor in four levels of 0, 100, 150, 200 kg N ha-1 (N0 to N3) and irrigation as a sub-factor in five levels of 0, 25, 50, 75 and 100 water requirement percentage (I0 to I4). In the irrigation system of this research, on-line drippers (surface drip irrigation) of Netafim company with design flow rate of 4 L hr-1 were used. Sub-pipes (laterals) approximately 5 m long were placed in the middle of every two rows of tea plants throughout the experimental plot (except plots without irrigation). Seven drippers with a distance of 0.7 m (one dripper per plant) were installed on 16 mm laterals. Drip irrigation scheduling in water stress period was conducted twice a week based on soil moisture monitoring and fertilization (nitrogen) program once a week during growth period by fertigation at plant root depth. The maximum yield average (2581 kg ha-1 of made tea) and WP(I+P) (0.685 kg ha-1 m-3) with average water use of 3845 m3 and 150 kg N ha-1 was obtained during the growth period. The average water consumption of deficit irrigation levels I3, I2 and I1 was estimated to be 3380, 2917 and 2454 m-3, respectively. The biennial average of the highest yield of made tea for irrigation treatments I3 to I1 was 2640, 1449 and 1225 kg ha-1, respectively. At all levels of deficit irrigation of the experimental years, increasing the amount of nitrogen fertilizer increased water productivity, so that the productivity values related to deficit irrigation levels of 75% of water requirement (I3) were higher than the other two irrigation levels (50% and 25%). The highest water productivity for deficit irrigation levels I3, I2 and I1 was related to the use of 150 kg of nitrogen fertilizer equal to 0.625, 0.615 and 0.555 kg m-3, respectively. Top dressing of 100 kg N ha-1 in rain-fed/no-irrigation conditions (192.7 mm of effective rainfall) resulted in 803 kg of made tea with rain water productivity of 0.42 kg ha-1 m-3. Due to the increase in yield (300%) and water productivity (60%) resulting from the application of drip irrigation fertilizer system compared to rainfed conditions, the application of this irrigation method to produce tea economically with less water and fertilizer consumption in tea growing regions, especially sloplands and highlands are recommended. In general, for more than 8000 kg of green tea leaves per hectare, application of 150 kg of nitrogen fertilizer and lower yield, application of 100 to 120 kg of nitrogen fertilizer as a solution in drip irrigation system (fertigation) is recommended

Global climate change is expected to cause increased temperatures and more unevenly distributed precipitation, resulting in severe drought, heatwave, and soil salinity in arid and semi-arid areas [4,5]. Also, poor irrigation management not only decreases water use efficiency but also the drought intensity. It is estimated that 30% of the global land surface will experience extreme drought by the 2090s [1]. Drought stress is the most serious abiotic stress that has a direct impact on crop performance [2]. Introducing new crops that are adapted to environmental stresses is one of the most effective methods for sustainable crop production and food security in arid regions [3]. Quinoa (Chenopodium quinoa Willd.), traditionally called the mother of grains, has the potential to grow under drought, tolerating levels as stresses in other crop species. Drought conditions are key abiotic factors affecting quinoa’s growth and development. However, to the best of our knowledge, no information is available about irrigation with partial root-zone drying management on quinoa. Therefore, the present study in greenhouses conditions was conducted to study the effect of irrigation management on the morphological and grain yield of quinoa. The finding would be useful to enhance food security in the context of global climate change. This research aimed to examine the effect of deficit irrigation and partial root-zone drying on morphophysiological properties and grain yield of quinoa (c.v. Giza-1) in Ferdowsi university of Mashhad during 2019 (winter-summer). Research Station is located in north-east Iran at 36° 16' N latitude and 59° 36' E longitude and its height from sea level is 958 meters. The seeds of Quinoa were planted at a depth of 1.5 centimeters in the loamy soil of each pot and were irrigated with tap water. The experiment was a completely randomized design (CRD) with three replications under pot planting conditions, four irrigation regimes (full irrigation-FI, deficit irrigation-DI, alternate partial root-zone drying-APRD, and fixed partial root-zone drying-FPRD). In the APRD and FPRD regimes, pots were separated into two sections equally in the vertical direction, and irrigation was supplied to one section each time and then switched to the drier sections (APRD), but in the FPRD regime, one section all during a time of growth was dried and irrigated. In limited irrigation treatments, 50% water of FI was applied either to the filed capacity in the pot in DI or to one side of the pot alternating in APRD, and to one side of the pot fixing in FPRD, respectively. At harvest, plant height, leaf number, and root length were measured. Shoot and root biomass was collected and determined after oven drying at 70oC until constant weight. Grains were collected and measured for yield/plant. The obtained data analyzed using statistical software of SAS (Ver. 9.4) and the means were compared using LSD test at 5 % percent levels. Results showed that irrigation strategies were statistically significant on leaf number, plant height, shoot and root biomass, and grain yield at 1% level and significant on root length at 5% levels. Results showed that the highest plant height and root length (89.7 and 15.3 cm) were in FI treatment and the shortest plant height (58.7 cm) and root length (11.4 cm) were in DI and FPRD treatment. The highest and the least Shoot and root biomass and grain yield were measured in FI (7.9, 1.53, and 15.5 g per plant) and DI (3.5 g per plant), FPRD (0.89 g per plant), and DI (10.2 g per plant) treatments, respectively. With 50 % reduction of water in APRD, FPRD, and DI compared to FI treatment, plant height was decreased by 13.8, 26.8, and 34.6 percent, respectively. Grain yield was decreased by 13.5, 27.4, and 33.3% in APRD, FPRD, and DI compared to FI treatment. From results, it can be concluded that quinoa plant growth is favored by APRD is an effective irrigation strategy to increase grain yield in drought-prone areas. Overall, APRD might be a wise approach for sustaining crop productivity in drought-stressed areas of the world to ensure food security.

Demand for water is increasing day by day due to population growth and increasing economic activities. Climate change, as a potential threat to both water supply and demand, has upset the balance between water resources and consumption, especially in arid and semi-arid countries. The result is a widening gap in water supply and demand, increasing social conflict, and the instability of aquatic ecosystems and the environment. Water resource planners in many parts of the world have come to the common understanding that conventional water resources alone can no longer bridge the gap between supply and demand and should focus on water resource planning where different options of development of water resources are available. In the meantime, the use of unconventional water resources as a promising option to alleviate the quantitative and qualitative pressures on conventional water resources worldwide is of particular importance. Unconventional water resources mainly include seawater, brackish water and effluents from drinking, industrial and agricultural uses, of which seawater desalination is of particular importance.However, exploiting these resources is economically and financially challenging due to their high costs. Therefore, it is necessary to carefully consider the opportunity cost of water supply in this way with the its benefits. In this paper, using economic analysis based on welfare theory, which is widely accepted as a decision-making framework in the selection and implementation of investment projects. For economic evaluation, the overall effect of the project on improving the economic well-being of the whole community is measured by estimating and comparing the collective benefits of the project over time. If the economic benefits of the project outweigh the costs, it means that the value of consumption created for the community as a result of the project is greater than the value of the resources sacrificed for the project by other uses. In this paper, the Persian Gulf Water Desalination and Transfer Project, which is being implemented to supply water to the mining industries in southeastern Iran, gross water supply benefits by the project are estimated based on its final production value (economic value) in consumer industries are evaluated against the investment, operation and maintenance costs of both parts of project, namely desalination and water transfer. The results of the net present value of the project indicate that the benefits of water supply for the mining industries in the southeast of the country through desalination and water transfer from the Persian Gulf is not only able to compensate all investment, operation and maintenance cost and cost opportunity money, but also can add a total of 59,127.2 billion rials to the economic welfare of society during the 30-year period of operation. It should be noted that the internal rate of return of the project is 22.3%, which is significantly higher than the basic discount rate (0.07). On the other hand, in order to attract private investors to invest in this field, projects in this field must have financial stability. Therefore, the economic evaluation of the project should include an analysis of the financial sustainability of the project from the perspective of stakeholders. The financial analysis of the project is similar to the economic analysis in form. Both evaluate the benefits of investing. However, the concept of financial gain is not the same as economic profit. As mentioned above, in economic analysis the effects of the project on the national economy or the welfare of the community as a whole are measured, while in financial analysis the profit of the project is estimated for the operator or project participants it becomes. For a project to be economically viable, it needs to be financially sustainable and economically viable. The financial instability of the project leads to the non-realization of its economic benefits. Indeed, a comprehensive economic analysis should answer the question of whether the project's financial costs are covered by its beneficiaries and whether there is a financial incentive for project participants. The basic test for evaluating a financial sustainability project is whether the financial project for repayment is too much of the participants' capital. The Persian Gulf water desalination and transfer project is implemented by the private sector; where 15% of the required investment capital is brought from the investor and 85% is financed by BOO method. According to the agreement between the private investor and the water-demanding industries, the (financial) price of selling each cubic meter of desalinated water on the place of the industries is based on the cost (financial) of both components, the desalination and the transfer of each cubic meter of water plus 30 Percentage of profit margin is determined. Accordingly, the financial income of the project is calculated by multiplying the selling price of each cubic meter of water by the amount of water allocated to different industries. The financial criteria of the project indicate the very good profitability of the project from the perspective of the private sector investor. According to the calculations, the financial rate of return of the project is 30.9% and the rate of financial return brought by the investor is estimated to be 33.2%, both of which are significantly higher than the cost of capital opportunity (interest rate of the facility, 19% for Rial loan and 7/7% of foreign currency loans). Therefore, it can be concluded that the implementation of the Persian Gulf desalination and water transfer project to supply the water needed by the country's mining industries has an economic justification. The economic benefits of supplying water through seawater desalination to meet the needs of the mining industries can cover the high costs of desalination and water transfer and justify its implementation from the perspective of the national economy, the financial sustainability of the project also indicates the existence of sufficient financial motivation for the private sector to participate in investment projects for desalination and seawater transfer projects with industrial and mineral use.