water productivity

In order to compare new wheat cultivars and lines, an experiment was implemented in the form of split plots (randomized complete blocks) with three replications for two years at the Chahartakhte research station, Shahrekord, located in the agricultural and natural resources research center of Chaharmahal and Bakhtiari Province. The main treatments included three levels of irrigation, corresponding to (FI) 100%, (I80) 80%, and (I65) 65% soil moisture deficiency, while the subplots featured six wheat cultivars (Mihan, Heydari, line CD-94-9, line CD-94-8, Oroom, and Pishgam). The results of analysis of variance showed that the effect of irrigation levels on grain yield, total yield, plant height, harvest index, 1000 grams grain weight, spike length, water use efficiency and water productivity were significant at 1% level. The highest amount of grain yield was obtained from the Mihan cultivar with FI treatment with 7.85 tons/ha, which were placed in the same statistical group with the yield of two cultivars, Heydari and Pishgam. The lowest amount of grain yield was obtained from the Heidari cultivar treatment with the I65 irrigation level with 2.81 tons per hectare. The highest water use efficiency and water productivity were 2.06 and 1.83 kg/m3, respectively, obtained from Mihan cultivar treatment in FI irrigation management. The lowest water use efficiency and water productivity were 1.13 and 1.01 kg/m3, respectively, obtained from Heydari cultivar and I65 treatments.

Wheat is one of the most important strategic agricultural products. One of the most important policies of the country is to achieve self-sufficiency in wheat production. The relatively large area under cultivation of this crop has caused a large volume of water resources to be consumed for wheat production. One of the solutions to further increase water productivity in wheat production is to use the drip irrigation method (Tape). This study aimed to investigate the effect of planting arrangement and lateral spacing on wheat water productivity at the Jolghe-Rukh Agricultural and Natural Resources Research Station in Khorasan Razavi Province during the years 2016 to 2018. This study was conducted using a T-test design and the samples were compared in pairs. Six treatments including a combination of planting arrangement (15, 20 and 30 cm) and lateral spacing (60 and 75 cm) and a furrow method were compared. The results of statistical analysis showed that the drip-Tape irrigation method with a spacing of 60 cm along with a regular planting arrangement of wheat rows with a spacing of 15 cm was superior to the other treatments implemented, and the difference in the studied traits was clearly evident compared to the furrow irrigation treatment. The highest yield and water productivity were obtained from this treatment (8500 kg/ha and 1.63 kg/m3), while the irrigation water consumption in this treatment was 21% less than the furrow irrigation method in the first year and 35% less in the second year.

The purpose of this research is to investigate the effect of nitrogen fertilizer and different irrigation levels on crop yield per unit area, water use efficiency (WUE) and economic land productivity (ELP) on potato crop in the South Karman-Jiroft Agricultural Research Center. In this research, irrigation level treatments in three levels including 100% full irrigation (WL1), 90% irrigation (WL2) and WL3 irrigation 80% and three levels of complete fertilizer 100% fertilizer (F1), 60% fertilizer (F2) and 40% fertilizer (F3) were investigated, and the investigated variables include crop yield, WUE and ELP. The results of this research showed that there is no significant difference between WL1 and WL2, but there is a significant difference between these two levels with WL3. This means that reducing the level of irrigation up to 100% compared to full irrigation will not have a significant difference on the crop yield and ELP. Therefore, the optimal level for the WUE, crop irrigation is 90%. Examining the simple effect of fertilizer levels also showed that there is a significant difference in the crop yield and WUE between F1 and F3, these two levels do not have a significant difference with F2, but there is a significant difference in the land value between F2 and the other two levels. Therefore, the 100% fertilizer level has the highest crop yield and ELP, which shows a significant difference with other levels. Finally, by examining the two-level effect of treatments at different levels, the results showed that the optimal level of fertilizer and irrigation, which has the highest ELP, crop yield and WUE, is WL2F1. Therefore, in this area, according to the existing conditions, this treatment is suggested.

Estimating the amount of irrigation water and assessing water productivity in gardens is particularly critical in the context of current drought conditions and water scarcity. This article examines the cultivation of walnut and almond trees from the perspective of water consumption. The study was conducted in Koran Village, located in the Esfandegheh area of Kerman Province. The permanent Gishki River serves as the source of water for surface irrigation in this region. Water is transferred from the river to storage pools and irrigation canals through a network of channels managed by local operators. The reference crop evapotranspiration was calculated using the Hargreaves-Samani equation, while irrigation water consumption was determined based on the volume of water stored in the pools and the area of the gardens. Consequently, the study assessed the implications of excess or deficit irrigation in relation to farmers' water management practices. The water productivity in the current irrigation conditions of the region was calculated for almond and walnut trees as 0.6 and 0.27 kg/m3, respectively. Water productivity in water shortage conditions for almond and walnut trees was determined to be 14% higher and 10% lower than in sufficient water conditions, respectively. Additionally, Ky of almond was 47% lower than walnut. Also, the economic water productivity achieved for almond trees is 1.8 times that of walnuts. The findings indicate that the cultivation of almond trees is more advantageous than that of walnut trees in the Esfandegheh region, particularly in terms of water consumption and economic efficiency, especially under conditions of water scarcity.

Potato is one of the most important food sources in the world and is considered one of the basic sources in different countries. Iran is the 13th producer of this product with the production of about five million tons of potatoes. The yield of potatoes is high compared to other crops, and for this reason, it has a higher water efficiency than other crops. However, potato yield is strongly dependent on the amount of irrigation water. This issue has caused special attention to be paid to the amount of irrigation water and many studies have been conducted on determining the optimal irrigation water. However, providing the right amount of irrigation water in each climate and irrigation system requires many experiments. These tests require spending a lot of time and money, which cannot be done in research centers in the current situation. To solve this problem, various plant models have been presented. The SALTMED model is such tool, accommodate different plants, soils, irrigation systems, irrigation management solutions, water qualities, and environmental stresses.

To carry out this research, the data collected from two research projects were conducted (the first project in 2012 and 2013, the second project in 2017 and 2018) in Shahrekord's research station. In the research projects, to manage irrigation in potato cultivation, two irrigation factors were investigated: the first factor includes different irrigation methods (S: drip, Su: subsurface drip, and F: furrow), and quantitative management of irrigation water as the second factor (FI: providing 100% of water needs, RDI80: providing 80% of water needs and RDI65: providing 65% of water needs) considering three repetitions. Data collected from the first year were used to calibrate the SALTMED model. The area of the plots was 40 m-2. Within each plot, four rows were planted with a row spacing of 75 cm and a seed spacing of 20 cm. The subplots were separated by one meter. In the surface drip irrigation method,  16mm drip pipes with an average flow rate of 1.75 L h-1 were used for each crop row. In subsurface drip irrigation, 16mm drip pipes with an average flow rate of 1.85 L h-1 were installed at a depth of 20 cm in the soil for each crop row. To evaluate the SALTMED model at this stage, the statistics of root mean square error (RMSE), normalized root mean square error (NRMSE), mean bias error (MBE), model efficiency (EF), agreement index (d), and determination of coefficient (R2) were used. Validation of this model was done using second-year data.

The highest and lowest differences between the observed and simulated values were 4.2 and 1.4 tons per hectare, respectively. The average difference between the observed and simulated values was 2.7 tons per hectare. The differences between the observed and simulated yields for drip, subsurface drip, and furrow irrigation methods were respectively 3, 1.9, and 3.1 tons per hectare. In addition, the accuracy of this model for simulating yield in the furrow irrigation method was lower than the other two methods. The highest and lowest difference between observed and simulated water productivity were 0.3 and 1.3 kg.m-3, respectively. The average of this difference was determined to be 0.7 kg.m-3. The difference between observed and simulated water productivity for drip irrigation, subsurface drip, and furrow irrigation methods was 0.8, 0.5, and 0.8, respectively. Based on the values of MBE statistics, the SALTMED model had an underestimation error in simulating yield and water productivity. The results of the NRMSE statistic showed that the accuracy of the SALTMED model for yield simulation was in the excellent category. The efficiency of the SALTMED model for yield simulation was acceptable based on two statistics EF and d. The R2 statistic for the simulation of potato yield by this plant model ranged from 0.88 to 0.99.

This research evaluated the SALTMED model for simulating potatoes' yield and water productivity under three irrigation methods furrow, drip, and subsurface drip. Using the recalibrated SALTMED model, a simulation of yield and water productivity was done to meet the water needs of 90, 55, and 45 % of potatoes for all three irrigation methods. A downward trend was observed between the reduction of water supply and potato yield in all three irrigation methods. The yield differences between the 100 and 90 %, and 90 and 80 % water supply in surface irrigation were 4.8 and 5.7 %, respectively. These values were respectively 18.6 and 8.7 % for drip irrigation and 13.3% and 1.7% for subsurface drip irrigation. Therefore, the slope of yield reduction until providing 80% of the water requirement was low in all three irrigation methods. The results showed that the SALTMED model had an underestimation error for simulating both parameters (MBE<0). However, the obtained error is negligible and the accuracy of this plant model was in the excellent category (NRMSE<0.1). Based on the results of EF (<0.88) and d (<0.99) statistics, the effectiveness of the SALTMED model was favorable for simulating both yield and water productivity. To determine the optimal amount of irrigation water, the recalibrated SALTMED model was used. The results showed that providing 80% of the potato's water requirement led to the achievement of an optimal yield and high water productivity.

Biochar as a soil amendment improves soil physical and chemical properties. Drought stress is one of the most important factors that limit plants growth. In order to study the effect of biochar on growth and morphological characteristics of coriander in a fine-grained soil under water stress, one factorial experiment in Randomized Complete was carried out in the research greenhouse of Urmia University, Iran. Experimental treatments included three levels of deficit-irrigation 100, 75 and 50 percent of water requirement of coriander (a1, a2 and a3) and three levels of application of biochar 0, 2.5 and 5 percent by weight percentage of each pot (b1, b2 and b3). The results of analysis of variance and comparison of the mean of measured traits (fresh and dry weight of plant, leaves, stems and roots) showed that these traits were significantly different under the influence of different levels of irrigation and biochar application. So that the highest value of each of these traits was observed in the treatment of complete irrigation and application of 2.5 percent by weight of biochar (a1b2) and the lowest value was observed in the irrigation treatment of 50 percent of water requirement and without biochar (a3b1). The highest water productivity based on fresh (3.26 kg/m3) and dry (0.49 kg/m3) of the coriander was obtained from a2b2 treatment. So, it can be concluded that the application of the appropriate amount of biochar reduces the negative effects of moisture stress and improves plant growth and development indicators compared to the control treatment. Therefore, it is recommended to use it for the plant in conditions where the plant is under drought stress or in greenhouses in order to reduce the amount of water consumed and improve the growth and performance of the plant.

Accurate knowledge of water balance components is necessary to optimize water consumption in agriculture. On the other hand, measuring water balance components is expensive and difficult. Therefore, the use of models that can simulate water balance values is important for water management in agriculture and water used by plants. Crop simulation models have been turned into essential tools for studying plant production systems. In the SSM-iCrop2 models, it is presumed that diseases and weeds are optimally managed and will not affect growth and yield. Additionally, except in cases where the model accounts for specific nutrients such as nitrogen, it is generally assumed that nutrient deficiencies are eliminated through fertilization. Therefore, parameterized and evaluated models are designed to fit these conditions. These factors are present in the field and affect crop growth and yield as well as water use. However, in several cases it is required to estimate yield and water balance components and irrigation water volume under grower conditions. Naturally, models parameterized using experiments are unable to simulate these conditions. Therefore, a model must be prepared so that it can simulate the real conditions of farmers. In this study, the SSM-iCrop2 model has been calibrated for the real conditions of farmers, and the purpose of this study is to use the SSM-iCrop2 model in simulating water performance and water balance for farmers.

In this study, the SSM-iCrop2 model was calibrated for farmers conditions using variables such as yield and harvest index, which are available for farmers’fields or are cheap to measure. The effect of factors such as pests and diseases, weeds and unsuitable nutrients, density and sowing date entered the model along with the calibration of three parameters of radiation use efficiency, maximum leaf area and maximum harvest index for farmers’ fields. Calibration was done by comparing the performance of farmers against the performance simulated by the model and by changing the parameters of radiation use efficiency (IRUE), maximum leaf area (LAIMX) and maximum harvest index (HIMAX). This calibration was done at Hashem Abad station in Gorgan for irrigated rice (paddy) and wheat. The simulated actual yield was calibrated with the actual yield. Due to the acceptable simulation of actual yields after calibration, it was presumed that other estimates made by the model are also reliable.

Measurement of water balance and other estimates of the model from growth and yield formation in the grower fields is expensive, but a calibrated model can estimate them at a low cost. In this study, it was shown that with the model calibrated for farmers' conditions, not other easily measured information (such as the irrigation water volume) can be obtained, with the assumption that the model accurately captures this information as well as performance. To evaluate the simulated real performance model, it was compared with the actual performance of farmers (Agricultural Jihad Report) after calibration. In addition to phenology, the SSM model simulates traits related to growth and yield, evapotranspiration values, irrigation water volume, runoff, available soil water during planting and harvesting, cumulative drainage, etc. The output of the model shows the amount of irrigation water is needed for a certain amount of performance in a given place (with specified rainfall and transpiration). The irrigation water volume calculated by the model was compared with the results of field tests from previous studies conducted by researchers at agricultural research centers. It was found that the model's output and the observed values were in good agreement. The root mean square error for rice and wheat was 216.6 and 157.6 kg per hectare, respectively, and the coefficient of variation and correlation coefficient were 4 and 85% for rice and 3 and 94% for wheat, respectively. Then, the irrigation water volume estimated by the model was evaluated and validated with the measured irrigation water volume in different crops (in Golestan province for different years). Based on the results of the evaluation, the coefficient of variation and the correlation coefficient for the simulated irrigation water volume were 8.9 and 98%, respectively, compared with the observed value. This calibration was done for rice (paddy) and irrigated wheat in the fields of Gorgan town, and the simulation and running were done using the meteorological statistics recorded in Hashem Abad weather station, Gorgan. Noting the fact that the actual yield has been simulated with good accuracy after the calibration, it was assumed that the other estimates of the model are also reliable. Thus, the calibrated model estimates them with low cost and appropriate accuracy and can complement field experiments.

This study discovered that the SSM_iCrop2 model, when calibrated for the conditions of farmers' fields, can accurately simulate both growth and yield traits as well as water balance characteristics. Notably, the model provides reliable estimates of irrigation water volume in farming scenarios, a crucial factor for agricultural planning and drought adaptation.

Due to the limitation of water resources in the production of agricultural products in the country and the need to improve water productivity in the production of horticultural products on the one hand and the economic importance of plum production in the country on the other hand, the investigation of management indicators such as the volume of irrigation water, yield and irrigation water productivity is necessary in the production of plums in the country. Plums are one of the most important orchard products, and the livelihood of a large number of farmers in different regions of the country, including Khorasan-Razavi province, depends on this product. Therefore, the current project was carried out with the aim of direct and field measurement of the water content of plum varieties in orchards under the management of local farmers in the producing regions of this product in the province. According to the latest statistics published by the Ministry of Agricultural Jihad (Statistical Yearbook of the Department of Agriculture of Khorasan Razavi Province in 2022), the area under plum cultivation in Mashhad and Chenaran regions is 328 and 75 hectares, respectively, and the yield per unit area in those two mentioned regions is 3905 and 6028 kg/ha, respectively.

In Khorasan Razavi province, two regions with highest area under plum cultivation were selected for evaluation, Chenaran and Mashhad. To conduct this research, 10 orchards in Chenaran region and 10 orchards in Mashhad region have been selected. The volume of irrigation water was measured in these 20 orchards during the irrigation season. The measurements were carried out in different irrigation and planting methods, various soils, different salinity of irrigation water and soil, and different plum varieties during the growing season of 2021-2022 without interfering with the farmer's irrigation management. The measured values were compared with the gross irrigation water requirement estimated by the Penman-Monteith method using the last 10 years meteorological data and also with the national water document values. Plum yield was recorded at the end of the growing seaso nand water productivity was calculated as the ratio of yield to total water (irrigation applied water and effective rainfall).

The results showed that the amount of applied water, the amount of plum yield and the water productivity in Chenaran region were 10899 m3/ha, 21.73 ton/ha and 1.9 kg/m3, respectively. The volume of applied water, the amount of plum yield, and water productivity in Mashhad region were determined as 10229 m3/ha, 13.11 ton/ha and 1.42 kg/m3, respectively. The volume of plum irrigation water in the regions varied from 4999 to 16862 and its weighted average (based on the cultivation area) was 10256 m3/ha. While the average gross requirement of irrigation water in the regions using the Penman-Monteith method using meteorological data of the last ten years and the national water document was 14964 and 12173 m3/ha, respectively. The average yield of plum in the selected orchards varied from 5560 kg/ha to 89800 kg/ha and the average was 14713 kg/ha. Irrigation water productivity in selected orchards varied from 0.4 to 7.09 and the average was 1.53 kg/m3. The applied water productivity in the selected orchards was 1.51 kg/m3.

According to the results of this research in Chenaran and Mashhad, the weighted average volume of irrigation water and the irrigation water productivity in plum orchards are 10256 m3/ha and 1.53 kg/m3, respectively. The volume of irrigation water to produce plum in these two regions was about 31% more than that in country and the irrigation water productivity was about 32.6% less than that in country. The volume of irrigation water, yield and irrigation water productivity in plum orchards in drip irrigation method were 9920 m3/ha, 18827 kg/ha and 1.88 kg/m3, respectively, and in surface irrigation method they were 11433 m3/ha, 14804 kg/ha and 1.31 kg/m3 respectively. The yield of plum and the irrigation water productivity in drip irrigation method, compared to the surface irrigation method, increased by 27 and 43%, respectively, and water consumption decreased by 13%. Comparing the volume of irrigation water used by farmers in the plum orchards with the gross irrigation requirement, shows that the farmers have no enough water for irrigation and unintentionally, they follow deficit irrigation in the plum orchards, and in fact, the farmers use water available for them. The average yield of plums with drip irrigation method was equal to 18.83 ton/ha, which is about 65.75% higher than the average yield of plums in the country. Based on this, plum cultivation in both regions and also the use of drip irrigation method in plum orchards cab is recommended.

Determining and analyzing the indicators of water management for the crops of the country plays an important role in the planning of the agricultural sector.This study was accomplished to investigate water management indicators of irrigation systems in Wheat production in the upstream region of Karkheh basin and specifically Honam plain in Lorestan province. 14 wheat farms were selected in the mentioned area and were subjected to agronomic and water monitoring during the cropping season. Wheat applied irrigation water was determined by recording the irrigation schedule and measuring the flow rates. The water requirement of wheat was estimated by Penman-Monteith method and by applying plant coefficients. The yield and water productivity for wheat farms were obtained at the maturity stage. The results of agronomic and water monitoring of selected wheat fields showed that the type of agricultural, irrigation and fertilizer management of farmers played an important role in the amount of grain produced. Irrigation applied water, yield and WP was statistically different during the growth season for the farms. The average yield, the volume of irrigation water, the productivity of the irrigation water and the productivity of the applied water of wheat in the sprinkler irrigation system were equal to 6845 kg/ ha, 2325 m3/ha, 3 and 1.52 kg/ m3, respectively, and in the surface system equal to 5000 kg/ ha, 3237 m3/ha, 1.3 and 0.94 kg/ m3, respectively. The monitoring of the irrigation program in the selected fields showed that the farmers irrigated the mentioned fields on average 41% less than the full irrigation requirement of the plant. One of the important reasons for this is the special attention of farmers in the region to plant crops with high profitability, such as alfalfa and clover, despite the need for more water than wheat.

The main purpose of this project was to measure the amount of saffron consumed water in farms managed by farmers in Razavi and South Khorasan provinces. 126 farms in two provinces were selected in two years (2017 & 2019). The amount of water consumed by saffron in the selected farms was measured by visiting the farms, completing the questionnaire, recording the irrigation program and measuring the water source discharge. Water requirement of saffron in different regions was calculated and compared with the amount of water consumed by farmers. Analysis of variance was used to investigate possible differences in yield, irrigation water and water productivity in saffron production. Analysis of the results showed that yield, volume of applied water and water productivity of saffron in two provinces was not significantly different. The average saffron yield, water productivity and water productivity plus effective rainfall were 8.3 kg/ha, 1.9 and 1.37 g/m3, respectively. The average irrigation water consumption was 4628 and 4594 m3/ha in the Razavi and South Khorasan provinces, respectively and the average of water consumed in two provinces was 4603 m3/ha. The range of water use changes in selected farms was high and between 1543 and 8914 m3/ha. In order to improve water productivity in saffron production in Iran, it is possible to increase yield per unit area or reduce water consumption per unit area with appropriate solutions. The average irrigation efficiency in the saffron farms of the two provinces was 55 percent.

Crop modeling is a widely used method for simulating the crop yield under different irrigation managements. Due that, in the study, a water-driven crop model, AquaCrop, was used to simulate and determine the optimal irrigation quantity and interval in Dehkhoda Sugarcane Cultivation and Industry Group (DH) farms. The data were collected from DH farms during 2019-2021. The total area under study was 230 hectares. The evaluation results showed that the AquaCrop model had an acceptable error for simulating yield (RMSE<5.6 ton ha-1) and water productivity (RMSE<2.2 kg m-3). In addition, the results of favorable efficiency (d>0.99), excellent accuracy (NRMSE<0.1) and high determination of coefficient (R2>0.94) showed that the simulation results of AquaCrop can be trusted. For this reason, 21 irrigation scenarios were simulated using the AquaCrop model in order to obtain the most appropriate irrigation amount and interval. Based on the results, close-end furrow irrigation with interval of seven days and the amount of 33000 m3 ha-1 was determined as a suitable option in terms of yield (132 ton ha-1) and water productivity (4 kg m-3). However, this scenario is for normal water conditions and if water stress conditions are created; a maximum of nine days for irrigation interval and at least 21000 m3 ha-1 is a better option for implementation in DH farms.

Camelina is an oilseed plant that could produce proper yield in arid and semi-arid areas with low water consumption. To investigate camelina response (Sohail cv.) to application of different amounts of irrigation water, this study was conducted in 2022-23 in Khatam District, Yazd Province. Treatments included drip tape irrigating based on 100% (full irrigation as control), 75% and 50% of full irrigation. Results showed that the effect of irrigation treatments on biological yield, grain yield, harvest index, plant height and protein percentage of camelina was significant (p<0.05). However, by reducing the volume of irrigation water, biological yield decreased significantly, such that biological yield of 75% and 50% treatments decreased by, respectively, 18.3% and 46% compared to the control treatment. The highest grain yield (2373.3 kg ha-1) was obtained with the application of 2384 m3 ha-1 irrigation water (control). By reducing the amount of irrigation water by 75% and 50%, grain yield decreased by 31.4% and 40.0%, respectively. The harvest indices were 22.6%, 19.0% and 25.1% for 100%, 75%, and 50% treatments, respectively. The highest plant height was 90 cm for the control treatment. The water productivity ranged from 0.88 kg m-3 for 75% treatment to 1.04 kg m-3 for the full irrigation. The highest proline content was observed for the treatments of reducing the volume of irrigation water, in which the amount of proline increased by 1.4 times compared to the control treatment. The results showed that the amount of irrigation water required for camelina was lower compared to the common winter crops, especially in tape irrigation method. Therefore, this plant could be used as a low water-demanding for delayed planting in winter season.

Considering the crisis of water resources and spatial distribution of fertile lands, in order to reduce water consumption and increase food security, it is necessary to use a suitable cultivation model. The purpose of this research is to achieve a suitable cultivation pattern using the method of determining virtual water exchanges in Kurdistan province. The data of this research during the 10-year statistical period (1389 to 1398) in Kurdistan province includes information on the cultivated area and yield of 22 garden crops, irrigation information, meteorological data, population, per capita consumption of food products and their prices, which are calculated in Microsoft Excel ( 2021) has been accepted. The indices related to water requirement values, total virtual water, green virtual water, blue virtual water and virtual water balance were calculated for all selected products. In addition, the lack of attention to the spatial distribution of horticultural crops increased the average virtual water by 26.75 cubic meters per kilogram in Kurdistan province. Virtual water includes 97.4% of the total virtual water for all products investigated in the province, which shows the dependence of the agricultural sector on irrigation in the region. In general, by adopting three indicators of total virtual water, unit value of water and the ratio of required water to available virtual water among the horticultural crops examined, the most suitable cultivation pattern for Kurdistan province in order of priorities is horticultural crops such as seed crops, cold-season crops It is dry, nucleated and grainy. Based on the results of this research, it is suggested to the provincial managers related to the issue that in order to reduce the pressure on the water resources of Kurdistan province and virtual water exchanges, instead of paying attention to the seeded and seeded

The water productivity index (WP), which is defined as the crop produced per unit of consumed water, has been considered as a key indicator for the optimal use of water in the agricultural sector. It has been heavily relied upon in the Iran's agricultural water policies and plans. However despite several years have passed since the introduction of this concept and index, unfortunately, water crisis still exists and is expanding in the country and measures to increase WP in agricultural products have not yet been able to effectively solve the country's water issues. In this review-analytical paper, the issues and challenges of using this index in practice have been discussed and the shortcomings, challenges, measures, and infrastructure necessary for the proper use of this index have been discussed and analyzed. According to the results, there are hidden issues and challenges (in 8 groups) in its application. The most important of which are the need to deeply understand the concept and definition of WP in the country's expert and management community, and the problems and issues of using the index from the aspect of lack of the required infrastructure for the proper impacts of improving WP in mitigating water scarcity. According to the identified issues and challenges, it was concluded that improving WP could not be a sole measure to solve the country's water crisis, because it fulfills just initial conditions. In order to fulfill conditions sufficiently and to implement related comprehensive measures and interventions, the necessary hardware, software, legal, and policy infrastructures must be provided.

The implementation of the Khuzestan Land reclamation Plan, has been provided a suitable platform to promoting research findings on the proper use of soil and water resources, agricultural inputs and increasing crop production. Therefore, this study was carried out in the agricultural year 2017-2018 with the aim of evaluating the water productivity resulting from improved management of canola production inputs and comparing it with conventional management in the northern lands of Khuzestan province. For this purpose, 11 farms (advanced management treatment) were selected to apply technical packages including irrigation scheduling, using the minimum tillage, applying balanced plant nutrition, raised bed planting, proper seed rate, according to farm conditions and farmer facilities. In each of these farms, the amount of applied water during the growing season, grain yield and water productivity were determined and compared with the surrounding farms data with traditional management (control treatment). The results showed that the average canola grain yield and water productivity increased from 2413 kg ha-1 and 0.51 kg m-3 in the control treatment to 2994 kg ha-1 and 0.69 kg m-3 in the superior treatment, respectively. This increase was statistically significant at the level of 1%.

Water scarcity and the recent droughts have multiplied the necessity of proper and optimal use of limited water resources. Drip irrigation is one of the new methods of irrigation that is used with the aim of optimal use of water and increasing water productivity in many agricultural products including wheat. This research was conducted in order to investigate the drip irrigation systems (Tape) implemented in the wheat fields of Hamedan province and compare it with other common systems during 2016-2018. In this research, first, farms were selected and evaluated by random sampling method. The measured parameters included the amount of irrigation water, yield, water productivity, water salinity and soil salinity changes. The volume of irrigation water in fields with drip irrigation varied from 2716 to 5760 m3/ha and was determined as 4153 m3/ha on average. The average volume of irrigation water in sprinkler and surface irrigation systems was determined as 4090 and 5918 m3/ha, respectively. The highest amount of yield was determined as 5581 kg/ha in the drip irrigation. The average yield in sprinkler and surface irrigation systems was estimated to be 4381 and 3000 kg/ha, respectively. The highest average water productivity (irrigation+ effective rainfall + leaching) related to the drip irrigation system and is 0.88 kg/m3 , and it was determined as 0.8 and 0.39 kg/m3 in sprinkler and surface irrigation system, respectively. Therefore, drip irrigation has increased water productivity by 10% and 125.6% compared to sprinkler and surface irrigation systems. Also, the results of this research showed that the salinity of the soil in the drip irrigation system increased at the end of the growing season compared to the beginning of the spring season. Therefore, leaching water requirement should be added to the amount of applied water (irrigation water + effective rainfall) in the drip irrigation system.

Water and nitrogen are the most important factors affecting the quantitative and qualitative performance of medicinal plants. Since the performance of the fertilizer level depends on the appropriate amount of irrigation water, it is important to examine the water and nutritional requirements of medicinal plants in order to achieve the desired quantitative and qualitative performance and the physical and economic water productivity indexes of these plants. Celandin (Chelidonium majus L.) plant is one of the very old medicinal plants, and all its parts, especially its sap and root, were used in the treatment of skin disorders, especially leprosy, toothache, and also as a choleretic, and in recent years most of its aerial parts, which are collected during the flowering stage, are used to treat some diseases, especially cancers of the digestive system. Also, all the parts of this plant contain orange sap rich in alkaloids Chelerythrine, Chelidonine, Sangunarin, Berberine, etc., which increases the importance of the production of this plant. There are many reports about the effect of irrigation interval and nitrogen fertilizers level in relation to various agricultural, garden and medicinal plants, but there is still no comprehensive and complete information about the effect of these factors and their optimal levels for the cultivation of Celandin medicinal plants. Therefore, it is necessary to evaluate the yield and indexes of physical and economic productivity of water in Celandin medicinal plant at different levels of irrigation and nitrogen fertilizer.

In order to investigate the effect of the irrigation interval and ammonium nitrate on the yield and indexes of physical and economic water productivity of Celandin (Chelidonium majus L.) medicinal plant, an experiment was conducted as a factorial in the form of a completely randomized design in three replications in the research greenhouse of the Faculty of Agricultural Sciences of University of Guilan in 2017. The factors include irrigation interval in three levels (4, 8 and 12 days) respectively as I1, I2 and I3 and nitrogen fertilizer based on ammonium nitrate in five levels (0, 45, 60, 75 and 95 kg per hectare) as respectively was N0, N45, N60, N75 and N95. To prepare the planting bed, the top soil of the garden, dune sand, and animal manure were mixed in the ratio (1:1:1) and filled in pots with an average diameter of 20 cm and a height of 18 cm. After preparing the soil sample, some physical properties (soil moisture coefficients of FC and PWP using a pressure plate device, soil texture using the hydrometric method and dry bulk density using the core sampler method) and chemical properties of the soil (calcium, potassium, phosphorus, nitrogen, organic carbon, pH and ECe) were determined. At the end of the experiment, when the plants flowered (about 225 days after transplanting), to calculate the weight of the roots and aerial parts, the plants were removed from the pot and their roots were separated from the aerial part. After washing the roots, each one was weighed separately with a sensitive digital scale (Sartorius model) with an accuracy of 0.001 grams. Then, with regarding the amount of water consumed in each irrigation treatment, the physical and economic water productivity indexes were determined based on the wet weight of the whole plant, which includes the root and aerial parts of the plant.

The results of variance analysis of data showed that the interaction effect of irrigation interval and amount of ammonium nitrate on yield and indexes of physical and economic water productivity was significant at the 5% probability level. Thus, the highest plant fresh weight was obtained with 92.92 g/plant in an 8-day irrigation interval with a fertilizer level of 95 kg/ha, and the lowest with 45.36 g/plant in a 12-day irrigation interval with a fertilizer level of 60 kg/ha. Also, the highest indexes of physical and economic water productivity based on benefit per drop and net benefit per drop based on the fresh weight of the total plant with 8.65 kg/m3 and 3463932999 and 17319665 rials/m3 respectively in the 8-day irrigation interval treatment with fertilizer level 95 kg/ha, and the lowest of them was obtained with 2.44 kg/m3, 9774464 and 4887232 rials/m3 respectively in the 4-day irrigation interval treatment with zero fertilizer level. In addition, 50% water consumption was saved in the 8-day irrigation interval treatment compared to the 4-day irrigation interval treatment. Therefore, I2 irrigation interval treatment with N95 ammonium nitrate fertilizer level is the most suitable option in terms of yield and physical and economic water productivity indexes for the production of the medicinal plant Celandin in greenhouse conditions.

Biochar as a porous material is rich in biological carbon in a stable form. Its structure is capable to store water and nutrients. Therefore, it is used for retention of such materials, especially in sandy soils. Biochar can improve water productivity in the agricultural sector in drought stress condition to achieve food security in the world. In order to study the effect of deficit irrigation and biochar on yield of coriander in a coarse-grained soil under water stress, this research was conducted using a factorial manner and a completely randomized design in the research greenhouse of Urmia University. The experimental treatments included three levels of irrigation: 100%, 75%, and 50% of the plant water requirement, and three levels of biochar application: 0, 2.5%, and 5% of the weight of each pot, which totally included 27 treatments. Irrigation was applied on the basis of plant requirement and soil water content below field capacity and the applied water was measured during the growing season. For each pot, quantitative parameters including weights of dry and wet plant, stem, leaf, and root were accurately measured. The results showed that the effects of irrigation levels and biochar on some measured parameters were significant at the probability level of 1% and 5%. The results demonstrate that by applying deficit irrigation, the measured quantitative parameters and plant yield decreased. The highest value of the parameters was obtained from the treatment of 100% water requirement and use of biochar up to the level of 2.5% of the soil. Therefore, applying suitable amount of the biochar as soil amendment improves coriander plant's growth and yield.

In most arid and semi-arid areas, water limitations are one of the main reasons for the reduced plant growth and yield under irrigation and dry land (rainfed) conditions. The aim of this study was to compare the morphophysiological responses of rapeseed cultivars to supplementary irrigation and dryland conditions. For this purpose, an experiment was carried out as a split plot in the form of a randomized complete block design with three replications during 2017-2018 in the Gachsaran Agricultural Research Station. Irrigation treatments were at four levels (no irrigation=I0, supplementary irrigation at flowering stage=I1, supplementary irrigation at grain filling stage=I2, and supplementary irrigation at flowering stage+ grain filling=I3) in the main plot, and cultivars Hayola 401, R. J. S, and Shirali as factorial in the sub-plots. The results showed that supplementary irrigation increased plant height, number of sub-branches per plant, 1000- grain weight, grain yield, and oil percentage compared to rainfed conditions. With supplementary irrigation, the weight of 1000 grains increased by 32% compared to rainfed. Grain yield increased from 755 in rainfed conditions to 2350 kg.ha-1 with two supplementary irrigations. With two supplementary irrigations, the oil content increased by 11.8% compared to the rainfed conditions. In all irrigation treatments, grain yield and oil content of Hayola 401 were higher than R. J. S and Shirali cultivars. In general, supplementary irrigation improved morphophysiological traits, yield, and percentage of grain oil. In rainfed rapeseed cultivation, with supplemental irrigations at flowering and grain filling, water productivity increased from 0.21 to 0.53 kg m-3 grain yield from 755 to 2350 kg ha-1 and oil percentage from 35.4 to 36.9.