جستجوی مقالات مرتبط با کلیدواژه « بهره‏وری آب » در نشریات گروه « آب و خاک »

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.

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.

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.

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.

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.

Agriculture is the largest consumer of fresh water in the whole world. Currently, almost 11% of the Earth’s total land surface is arable, which is expected to reach 13% by 2050. Roughly 17% of these lands are subject to modern form of irrigation management, which constitutes about 30-40% of the gross agricultural output. Reducing water consumption and increase water productivity in agriculture, requires a correct understanding of the biological response of crop to water. The ever-increasing growth of the population and the limitation of fresh water resources have led irrigation experts to new and efficient approaches in making decision to increase water productivity. The lack of scheduling in irrigation or their incompatibility with weather conditions, soil, irrigation system, agricultural restrictions and different phenological stages of crop, has caused severe losses in irrigated fields. Crop modeling and field data measurement can help irrigation experts improve irrigation scheduling in field and reduce water losses. Coupling in-situ measurement and crop modeling during the growing season is one of the useful solutions to improve irrigation scheduling in different farm conditions. In this paper, AquaCrop was calibrated for maize (Zea mays L.) in research farm of Ferdowsi University of Mashhad with comprehensive dataset. Variations of soil water content at different depths and also different growth indices was monitored during one growing season. The main novelty of this research is the targeted use of AquaCrop software to reduce water consumption by knowing the phenologically sensitive stages.

In-situ and in-lab measurements along with plant modeling, have been the two main parts of this research. First, the input files of the AquaCrop software were prepared and calibrated for maize during one growing season. The outputs of software including variations of moisture, biomass produced during the growing season and final yield were compared with the values measured in the field. After ensuring the accuracy of calibrated software, an improved irrigation scheduling was investigated. Subsequently, by means of crop modeling, the sensitive intervals of the crop to soil water stress as well as the thresholds of yield reduction in different stages of growing season were determined with the aim of improving irrigation scheduling in maize field. Biomass reduction, dry yield production, and the changes in water use efficiency during the growing season were investigated according to different amounts of moisture reduction in root zone, and irrigation scheduling was fulfilled by applying stress to less sensitive stages. The software was first run in Net Irrigation Requirement mode. Then, different amounts of drought stress were applied to each of the growth stages of the crop, and the other stages were kept constant in non-stressed condition. Dry yield and biomass reduction as well as water productivity changes were obtained for each stage. According to the threshold values and the amount of yield reduction at each stage, it is possible to fine-tune the time and amount of applying stress to crop. Furthermore, according to the moisture profile of the root zone, the drained water was significantly reduced in field. In this research, in order to increase accuracy in moisture measurement and prevent errors, an equation was developed to convert the mV output of sensor to volumetric moisture. At each moisture measurement, the PR2 sensor reports a number in mV for each depth, which is converted to volumetric moisture using device's conversion equation. This equation can vary according to field and soil condition. To develop the conversion equation, six same pots with a height of 40 cm and diameter of 30 cm were filled with the desired field soil, and the access tubes were placed horizontally inside them. The soil inside these pots was completely saturated and exposed to air for drying. During the drying period of the pots, the soil moisture was measured regularly using PR2 sensor and at the same time by weight method. After these measurements, calibration curves for PR2 sensor were obtained using the alpha mixing method for different depths.

The Pearson correlation coefficient for measured and simulated moisture by software, was 0.84 and the root mean square error was 12 mm. Also, the value of Pearson correlation coefficient for measured and simulated values of biomass was equal to 0.99 and mean square root of error was 1.3 ton/ha. The results showed that the vegetative stage of crop was sensitive to drought stress and caused a significant yield reduction at the end of the growing season. The stage of germination and flowering were less sensitive, such that the decrease of moisture up to 12.3% compared to the Net Irrigation Requirement mode would not change the final yield of the crop. The improvement made in the field resulted in no change in the amount of biomass and dry yield (0.38% increase in biomass and 0.52% increase in dry yield), at the same time 26.6% decrease in depth of irrigation water, 85.6% decrease In drainage and increasing the efficiency of evapotranspirated water, it has increased from 4.66% to 4.67% kg/m3 compared to condition before modify. Before modify, the farm was managed in traditional way.

More research in the field of irrigation scheduling and providing comprehensive instructions to farmers in different weather conditions and different irrigation systems, taking into account different management approaches in allocating water to different parts of the farm along with investigating the effects of saline water irrigation, can be topics for the next research should be for experts in this field.

The Water Productivity (WP) of the Darbasti Irrigation System (DIS) was evaluated in Alfalfa cultivation in the Markazi Province. The evaluation included three patterns of sprinkler placement: 8x8 meter (SS-88), 8x10 meter (SS-810), and 8x12 meter (SS-812). The Distribution Uniformity (DU), Coefficient of Uniformity (CU), Application Efficiency of Low Quarter (AELQ), and WP were determined in the years 2018 and 2019, after the third (HA-3), fourth (HA-4), and fifth (HA-5) yield harvests. The results showed that the average CU in the SS-88 pattern was 84.76% in the first year and 86.34% in the second year. This pattern had the highest CU compared to the other two patterns. The DU in SS-88, SS-810, and SS-812 patterns in the first and second year was 77.3%, 79.31%, and 75.38%, 77.66%, and 70.11%, 70.88%, respectively. These results indicate very good, good, and relatively good performance in each of the patterns, respectively. Moreover, there was a significant difference at the one percent level in the AELQ between the first and second year for all three patterns. The results showed a significant difference at the level of one percent between the SS-812 model and the other two models. The WP of alfalfa was 1.84 kg/m3, 1.87 kg/m3, and 2.28 kg/m3 for SS-88, SS-810, and SS-812 patterns, respectively, in the first year. In the second year, this index was 2.43 kg/m3, 2.3 kg/m3, and 2.4 kg/m3 for the same patterns, respectively. Generally, the SS-810 pattern of sprinkler placement is a suitable choice based on performance indicators.

This research was conducted with the aim of evaluating the WOFOST for simulating the corn yield and water productivity in two different conditions of water amounts and nitrogen fertilizer supply.In the first research project, the factors of irrigation water amount in four levels and nitrogen fertilizer in four amounts and in the second project, fertilizer in four levels and fertilizer splitting were considered.The results showed that in the first projct, the accuracy of the WOFOST model for simulating water yield and water productivity was in the excellent and medium categories, respectively, while the accuracy of this model in the second project was determined in the excellent category for both aforementioned parameters.The efficiency of the WOFOST model for simulating yield in both project and water productivity in the second one was acceptable, but for simulating water productivity in the first project was in poor conditions.In the first project, changing the nitrogen fertilizer consumption from N1 to N4 caused an increase in the difference between yield in observation and simulation conditions.The amount of irrigation water had no effect on changing the WOFOST accuracy and error.In the second project, increasing the distribution of nitrogen fertilizer from T1 to T2 caused the error of this model to decrease from 6.5 to 3.6 percent.Based on the results, it is necessary to conduct more studies to use the WOFOST model to simulate corn in different amounts of irrigation water, but this model can be used to simulate corn in different amounts and splitting of nitrogen fertilizer.

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

Reforming the cultivation pattern is a program that the government pursues with the aim of achieving sustainable agricultural development and maintaining food security.Protection of basic production resources,self-sufficiency in the production of basic products and maintaining agricultural employment are among the goals of this program.In this regard,this research was carried out with an emphasis on the protection of water resources in the Kabudrahang plain of Hamadan province.Using linear programming modeling for the studied area, optimal patterns were determined. Water resource protection policies were examined and tested with two scenarios of reducing the use of underground water by 30 and 50% and the scenario of self-sufficiency in wheat production.The results showed that the water resource protection policy reduces the planned efficiency of the cultivation pattern from 2.44% to 24% compared to the current pattern.The area under cultivation of rainfed crops also increased and the area under cultivation of irrigated crops decreased.The area under cultivation of cucumbers and tomatoes increased, but the area under cultivation of fodder and water grains decreased.Self-sufficiency of wheat under the conditions of the existing and optimal cultivation pattern was achieved, but in the scenarios of water resources protection,self-sufficiency was not possible without applying the condition.Under the scenario of self-sufficiency of wheat, the planned efficiency and the use of labor decreased more than the scenarios of protection of water resources.According to the research findings, in order to protect water resources and sustainable exploitation of these resources,it is necessary to control and reduce their exploitation by 30 to 50 percent.

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.

Alfalfa is irrigated by drip, strip, Furrow and rain irrigation methods. Surface irrigation methods are unjustifiable and not economical due to the low potential of irrigation efficiency in dry areas. Rain irrigation methods cannot be justified in hot and dry areas due to high evaporation and high water requirement of alfalfa. Alfalfa is a plant whose leaves are sensitive to burns caused by poor quality water as a result of water spraying in the rain irrigation method (Hengeller, 1995). Micro irrigation methods (surface and subsurface drip) are among the alternative methods of rain methods. The subsurface drip irrigation method has not been developed in Iran due to the existence of ambiguities and some dark and unclear points regarding its efficiency for crops (clogged outlets, salt accumulation, risk of blockage of pipes by roots). These concerns require that before any development of subsurface drip irrigation method for different crops, necessary researches should be done in this field. Therefore, conducting any research on the efficiency of this method for alfalfa, which is a valuable fodder plant but requires a lot of water, seems necessary. This research was conducted with the aim of investigating the effect of subsurface drip irrigation method on alfalfa yield, the amount of water consumed and determining the appropriate distances and depths for sub-pipes.

In order to investigate the effect of installation depth and distance of irrigation strips (laterals) in subsurface drip irrigation method on yield and water use efficiency in alfalfa cultivation, a study was conducted for two years on the farm of Damghan Agricultural Research Station. The design was implemented in the form of split strips based on randomized complete blocks with two factors and three replications. Factors included: 1- Distance of irrigation strips from each other in three levels (80, 100 and 120 cm) 2- Depth of installation of irrigation strips in two levels (30 and 45 cm below the soil surface). Depth of strips installation was considered as the main factor and distances as the sub-factor. The length of each experimental plot was 60 m and the width of the plots for the distances of 80, 100 and 120 cm were selected as 4, 5 and 6 m, respectively. Strips irrigation with a with a diameter of 20 mm with a discharge of 1.6 (lit/hr) and a distance of 60 cm for each dropper were selected. After preparing the ground and sowing the seeds, the subsurface irrigation pipes were placed (according to the treatments) with using the machine. Irrigation water was calculated by Penman-Monteith method and was given to the plant with an irrigation cycle of 4 days.

The results showed that the effect of pipe spacing on product yield (dry matter) and water use efficiency was significant, but the effect of pipe installation depth on yield and water use efficiency was not significant. The interaction effect of distance and depth of tapes irrigation on crop yield and water use efficiency was significant. There was no significant difference between crop yield in treatments with lateral distance of 80 and 100 cm. With increasing lateral distance from 80 to 120 cm, crop yield decreased sharply. Due to the yield of treatments and the cost of subsurface drip irrigation, the treatment of lateral distance of 100 and depth of 45 cm was suggested as the superior treatment.

The subsurface drip irrigation method for perennial crops is one of the efficient and appropriate methods. This method has a much higher efficiency than other irrigation methods due to the reduction of evaporation losses and the increase of irrigation efficiency especially in arid and semi-arid areas. The non-interference of irrigation in this method with the traffic of agricultural machines (especially during harvest) increases the ability and functionality of this method. But one of the problems of this method is the damage of rodents to the sub-pipes under the soil surface, which makes it difficult to determine the places of damage and repair them. Based on the results of this research, to prevent the damage of rodents, it is recommended to fight against these rodents and also to increase the installation depth of secondary pipes up to 50 cm. Clogging of droppers caused by poor filtration performance and penetration into and around the pipes are other problems of this method. To avoid these problems, it is recommended to inject acid and herbicide regularly into the irrigation system.

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.

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.

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.

Rice is one of the most important agricultural products in the world. Rice cultivation in Iran has great economic and social importance. Mazandaran province is one of the most important rice production centers in Iran, accounting for 44% of the Iran's rice production. Due to the high consumption of water in the agricultural sector, the optimal use of water resources in agriculture is necessary.The water required by rice is directly related to evapotranspiration. The most reliable method of calculating evapotranspiration is using a lysimeter. The purpose of this experiment is to calculate the evapotranspiration of different varieties of rice using mini-lysimeters and to introduce the best variety for cultivation.

The experiment was conducted as randomized complete block design with three replications and eleven treatments, at Rice Research Institute of Iran (Amol) during the 2020. The treatments included different rice varieties in 11 levels T1: AR2, T2: AR6, T3: AHS, T4: DAH, T5: 1117, T6: 952, T7: 956, T8: E104, T9: S715, T10: Tarom, and T11: Shiroodi. Mini lysimeters with open bottom and closed bottom had a diameter of 60 cm and a height of 50 cm. Field soil was sampled from 0 to 30 cm depth and studied in the laboratory. The date of transplanting was similar in all rice cultivars The planting density of seedlings was 20×20 cm and 7 seedlings were placed in lysimeter. The lysimeters were placed 6 cm above the ground in the soil. The seeds were planted in a treasury and the seedlings were placed in the lysimeter after 30-35 days (after 3-4 leaves and height 25-20 cm). Water management in lysimeters was in the form of flooding (5 cm). Finally, variance analysis of the obtained data was done using SAS software and the mean of the treatments were compared through the least significant difference (LSD) test at 5% probability level.

The results showed that different varieties and lines of rice was effective on infiltration, evapotranspiration, yield, water consumption and were statistically significant at 1% level of probablity. The highest and lowest evapotranspiration with averages of 4938.7 and 3747 m3/ha belonged to T9 and T5 treatments, respectively. The highest and lowest yields with averages of 7773.7 and 2938.1 kg/ha belonged to T8 and T6 treatments, respectively. The highest and lowest values of deep percolation were observed with averages of 303.3 and 185.3 mm in T9 and T5 treatments, respectively. The highest and lowest amount of applied water with averages of 9972 and 7600.3 m3/ha belonged to T9 and T5 treatments, respectively. The highest and lowest water productivity with averages of 0.98 and 0.3 kg/m3 were related to T8 and T9 treatments, respectively. The results showed that the length of the plant growth period was different in the tested cultivars and lines and it was effective on the amount of water consumption..

Finally, in the normal conditions of the region, line E104 is introduced as the best treatment due to the production of maximum grain yield, while in water shortage conditions, the line 1117 is recommended for planting due to less water consumption.

In this research, the effect of irrigation water salinity and salicylic acid spraying were investigated on the yield of shallot (Qazvin local variety). Water salinity treatments at four levels of 2(S1), 4(S2), 6(S3), and 8(S4) dS.m-1 and salicylic acid at four concentrations of 0(A1), 0.5(A2), 1(A3) and 2(A4) mM were applied in the greenhouse. The experiment was performed as factorial and in a completely randomized design, with three replications. Soil moisture was measured daily, and irrigation scheduling was done based on it. Results showed that salinity stress reduced crop water uptake and shallot tuber weight. Salicylic acid application improved crop water status and increased tubers weight under salinity stress. A4 treatment was the ideal concentration for maximum yield. Application of 2 mM salicylic acid at salinity levels of S1, S2, S3, and S4 increased tubers yield by 11.6%, 32%, 40% and 91%, respectively, compared to the control (A1). The response of dry yield to evapotranspiration showed that by increasing salinity stress, percentage of yield decreased more than the percentage of evapotranspiration. Use of salicylic acid decreased dry yield sensitivity to salinity stress, such that from treatment S1 to S4 yield response coefficients (Ky) were between 1.01- 1.62 (in A1 treatment), 0.93- 1.3 (A2), 0.48- 1.09 (A3) and 0.31- 0.97 (A4). The effect of salicylic acid on water productivity were calculated between 2.13- 1.14 (in A1), 2.15- 1.68 (A2), 2.26- 2 (A3), and 2.38- 2.19 kg.m-3 (A4). In conditions of using saline water for crop irrigation, application of salicylic acid will increase water productivity. Based on the experiment results and in conditions of lack of high-quality water for irrigation, salicylic acid spraying on crops will be a suitable method to reduce the harmful effects of salinity stress.

Water scarcity is the most important factor limiting the production of agricultural products, especially in arid and semi-arid regions. Application of some materials such as superabsorbent polymers in soil increases water retention in soil and thus reduces water consumption and fertilizer leaching. These materials can reduce the effects of dehydration on the plant and lead to increased yield in arid and semi-arid regions. In order to investigate the effect of superabsorbent under water stress conditions on yield, yield components and some physiological characteristics of corn, experimental plots were conducted in the form of split plots in a randomized complete block design in Gotvand region in Khuzestan province. Three treatments of Aquasorb 3005 (600,300,0 kg / ha) A1, A2 and A3 and four irrigation strategies (50,75,100,125) percent of water requirement I1, I2, I3 and I4 in three replications for two growing seasons, respectively Summer 2019 and spring planting 2020) were considered. Irrigation planning, biological yield, harvest index and canopy cover were measured at different stages of growth seasons, based on which a growth simulation model was presented using AquaCrop software. The results of this test showed that the use of Aquasorb 3005 increased product performance by one percent. In addition, the results show the effect of superabsorbent application and irrigation planning on improving water efficiency. The highest grain yield in spring and summer cultivation was related to I2A3 treatment equal to 9055 and 9255 kg / ha, respectively, and the lowest yield in both crops was related to I4A0 treatment equal to 5977 kg / ha in spring cultivation and 6344 kg / ha in summer cultivation.