جستجوی مقالات مرتبط با کلیدواژه « pressurized irrigation » در نشریات گروه « کشاورزی »

The present research was conducted with the aim of applying the theory of planned behavior in investigating the intention of farmers to use pressurized irrigation system. To achieve the goal of the research, the descriptive-correlation method based on the structural equation model was used. The statistical population included farmers in the central part of Baghmolek county (N=3005). The sample size was 343 people using Morgan's table and sampling was also done in a stratified method with proportional allocation. The instrument of data collection was a questionnaire, the validity of which was based on the opinion of the university faculty members and its reliability was through Cronbach's alpha, also, in order to determine the validity of the structure, the average variance extracted index (AVE) was also confirmed in determining the reliability of the model from the composite reliability index (CR), the homogeneity reliability index (Rho). The results of the structural equation model showed that the variables of attitude, subjective norms and perceived behavioral control predicted 76% of the changes in the variable of intention to use pressurized irrigation system. According to the findings of the structural equation analysis, the variable of knowledge predicted 87% of the changes of the variable of attitude towards the acceptance of pressure irrigation system. Since there is a significant relationship between the research constructs and the farmers' behavioral inclination towards using the pressure irrigation system.

Considering the limitation of water resources and the need to increase water productivity in the production of agricultural products, the development of new irrigation systems has been one of the most important policies and activities of the agricultural water sector in recent decades. The purpose of this research is to quantitatively investigate the development of pressurized irrigation development in Iran and compare it with other countries and regions of the world using the pressurized irrigation development index, and finally the estimation of the optimal and expected level of its development for the country. According to the results, the PDI index until the end of the sixth development program (2020) is 21.4%, which is low compared to other 23 selected countries. Using the multivariable correlation method between the values of the variables affecting water management such as per capita withdrawal, the share of withdrawal from water resources in the agricultural sector, the area of irrigated lands, and the PDI index of 14 selected countries and applying values like for the Iran country, the desired and expected level of pressurized irrigation in the country was estimated at 49.2%. In other words, in the coming years it is possible to reduce the negative and undesirable effects of the unbalanced development of modern systems on water resources and the environment, and prevent the occurrence of the phenomenon of "rebound effect", in a favorable and potential way, up to half of the irrigated lands in the country should be equipped with pressurized irrigation systems. Meanwhile, according to the latest statistics, until the beginnings of 2023, the PDI has reached to 30% (2.9 million hectares). Therefore, there is still room for further development in terms of the necessary arrangements and under the condition of creating infrastructures, and necessary control rules and regulations by the related organizations.

This study aimed to evaluate the environmental and economic effects of the development of mini-bubbler pressurized irrigation projects as a modern irrigation system in Birjand County, South Khorasan Province, from the perspective of farmers and users, so the quantitative and qualitative processes of these irrigation projects can be evaluated. Data collection was conducted with a survey technique and the results showed that most of the farmers had a favorable assessment of the environmental and economic effects of the plan. The economic factor was found to be the most important factor during the evaluations, which included the variables of reducing the time required for irrigation, increasing the amount of production per hectare, increasing the cultivated area, reducing labor costs, reducing water and irrigation costs, improving the quality of products, and increasing the income from agriculture, which explained ca. 26.2 percent of the total variance. The second factor was the environmental factor, which includes the variables of the more appropriate use of fertilizers and pesticides, reduction of plant diseases, reduction of weeds, and prevention of soil salinization, which explains 21.6 percent of the total variance. Also, the effects of mini-bubbler irrigation on agricultural inputs were also evaluated, which included the variables of less water consumption, less seed consumption per hectare, compliance with the cultivation pattern, and increasing the mechanization factor, and explained 17.8 percent of the total variance. The social factor also includes the variables of gaining social credit, the cooperation of users in maintaining the system, and observing the irrigation schedule, and it explains 11.2 percent of the total variance. Finally, based on the obtained results, suggestions have been made for the success of implementing and using such projects.

In Iran, pressurized irrigation systems cover a large area of agricultural land, but water use efficiency remains low because farmers tend to do deficit (over) - irrigation due to their lack of knowledge of crop water requirements. To address this issue, irrigation systems can be automated, and it is important to estimate crop water requirements accurately. This can be done based on soil moisture deficit or meteorological data. The water required can then be applied using a volume meter or by determining irrigation time based on the sprinkler flow rate. The study aimed to compare crop water requirement estimates based on soil moisture deficit and meteorological data, as well as the amount of water applied using volume and time-based methods.The study was conducted in the research farm of Razi University, Kermanshah, Iran, on a sprinkler irrigation system equipped with pressure and flow measuring devices, pressure switches, and electrical valves. The field was under corn cultivation, and four types of irrigation management were evaluated, which included a combination of two methods of determining crop water requirement (soil moisture deficiency and meteorological data) and two methods of irrigation application (time or volume). The four treatments were soil moisture - time (MT), soil moisture - volume (MV), weather - time (WT), and weather - volume (WV). The crop water requirement was calculated using the Penman-Monteith formula based on daily weather data. Soil moisture was measured at different depths one day before irrigation, and the soil moisture deficit was calculated to determine the crop water requirement based on soil moisture. The irrigation volume for each sprinkler in the irrigation cycle was calculated using equations that written in the paper.In the volumetric-based method (treatments WV and MV), the volume of water applied was measured using a water meter with a precision of 0.1 liters, and irrigation was stopped after passing the required volume of water. In the time-based method (treatments WT and MT), the irrigation time was calculated by dividing the irrigation volume by the average flow rate of the sprinklers (3 liters per second), and irrigation was stopped after the calculated duration. The actual sprinkler flow rate was calculated based on the volume of applied water and irrigation time in each treatment and irrigation round. Crop yield was measured at the time of harvest in the studied treatments and a control treatment managed by the Faculty of Agriculture. The irrigation treatments were not applied in the first month of the growth period due to field limitations.The results show that the crop water requirement calculated based on meteorological data at the beginning and end of the growing period was more than the method based on soil moisture. In total, the amount of crop water requirement calculated based on soil moisture was 8% more than the meteorological-based method. The volume of applied water in treatments of MT and WT was 14 and 8% more than in MV and WV treatments, respectively.The actual flow rate of sprinklers was different from the design flow rate due to irrigation situations in other parts of the farm. The average discharge of sprinklers (12 irrigation events) in WT, MT, WV, and MV treatments was 2.79, 3.03, 3.27, and 3.12 l/s, respectively. The irrigation time in volume and time-based methods also showed a significant difference. The irrigation time in MT and MV treatments was 10 and 18% longer than in WT and WV treatments, respectively. The study found that due to the non-uniformity of sprinkler discharge, applying irrigation by volume method is better than the time-based method. The results suggest that the MV treatment, which determined the amount of irrigation based on soil moisture deficit and applied it using a volumetric method, is a suitable option for automating sprinkler irrigation systems in the studied region.

Due to the increasing growth of population and changes in lifestyle, the pressure on water and soil resources has increased, thus, proper management of these resources has vital importance. This research was conducted with the aim of evaluating and comparing the effects of furrow, surface, and subsurface drip irrigation on water productivity, yield, and yield components of spinach in arid and semi-arid climatic conditions of Ahvaz. For this purpose, an experiment in the form of randomized complete blocks with three treatments of irrigation methods including furrow irrigation (FI), surface drip irrigation (SDI) and subsurface drip irrigation (SSDI) was done in three replications in the research farm of the Faculty of Water and Environmental Engineering, Shahid Chamran University, Ahvaz, in 2021. According to the results, the amount of irrigation water used in the FI treatment was 1066 m3/ha and in the SDI and SSDI it was 787 m3/ha, which showed a decrease of 26.17%. In FI, SDI, and SSDI, the average yield of spinach plant (total fresh weight of leaves and stems) was equal to 23.56, 30.17 and 19.28 g and irrigation water productivity was 0.353, 0.613 and 0.392 kg/m3, respectively. In both yield and irrigation water productivity, the SDI treatment had a significant advantage at 5% level compared to the other two treatments. The effects of irrigation treatment on the characteristics of root length, stem length, total length, number of leaves, number of fresh leaves, leaf chlorophyll content and harvest index were not significant. Generally, considering water productivity as criterion, surface drip irrigation is more suitable than furrow irrigation for spinach cultivation.

Drip tape irrigation, if designed and implemented correctly, is an effective way to increase irrigation efficiency. The present research was conducted in order to investigate the effects of plastic mulch and discharge on the soil wetting pattern dimensions and water retention from a linear source. For this purpose, an experiment in the statistical design form of random complete blocks with four treatments including two factors of application or non-application of plastic mulch and discharge (2 and 4 liters per hour) was designed in three replications. This research was carried out in farm of the Faculty of Water and Environmental Engineering, Shahid Chamran University of Ahvaz, in a soil with silty clay loam texture. The soil wetting pattern dimensions, 24 hours after the end of irrigation were determined. The soil moisture difference between the second and fourth days after irrigation was considered as a measure of soil water retention. The soil moisture was determined after 24 and 72 hours from the end of irrigation. According to the results, with the application of the mulch, the depth, width and wetted area of the soil increased by 13.59, 20.25 and 38.54 %, respectively, compared to the non-mulched treatments, which was significant. The soil moisture difference between the second and fourth days after irrigation decreased from 1.96% in the non-mulched borders to 0.65% in the mulched borders. With the increase of discharge from 2 to 4 liters per hour, the soil wetted depth decreased from 27.22 to 23.55 cm, the soil wetted width increased from 26.72 to 31.88 cm, and the soil wetted area increased from 602.17 to 658.28 cm2, which indicates significant effect of increasing discharge on these parameters in all cases. The increase in discharge increased soil water retention, but this effect was not significant. The application of mulch has a greater effect on increasing the soil wetting pattern dimensions and water retention than the increase in discharge. Therefore, the use of plastic mulch is recommended to increase the efficiency of the drip irrigation system.

In recent years, the supply of energy for irrigation systems of pistachio gardens in Pakdasht is an important issue. With the implementation of targeted subsidies plan, the price of energy has increased significantly. In these conditions, the use of solar energy is the best solution, especially for areas away from the national electricity grid.

In this study, drip irrigation system was designed for 4 pistachio gardens in Pakdasht with areas of 12, 24, 48 and 96 ha and slopes of 0, 1, 2, 3 and 4%. Irrigation was done in two modes: 24-hour irrigation, 12-hour irrigation, then the annual investment costs of the solar system and the national electricity were calculated.

Comparison cost of solar equipment in 12 and 24 hour irrigation showed that in the slope of 4%, the cost of solar equipment in 24-hour irrigation for 12, 24, 48 and 96 ha were 0.6, 0, 68.45 and 97.36 million Rials more than cost of solar equipment in 12-hour irrigation and the investment cost of mechanical equipment and purchasing pipes in 12-hour irrigation were 9.68, 70.46, 240.93 and 451.25 million Rials more than cost of them in 24-hour irrigation, respectively. In general, total cost of the solar system in 24-hour irrigation is less than 12-hour irrigation. Selected solar system (24-hour irrigation) was compared with a pumping system connected to the national electricity grid. The comparison showed that economic feasibility of solar system is depend on the pumping station power and distance of gardens from the national grid.

 Education is the main basis for the growth of the individual and society and plays an important role in the sustainable development of a country. Education in the agricultural sector plays an important role in human resources supply. Numerous studies have been conducted to achieve educational solutions around the world. In Nigeria, educational videos were used to educate farmers in the form of animation, and the results of this study showed that knowledge transfer through information and communication technologies has a positive and significant effect (Mirgohar and Movahed Mohammadi 2008). Inside the country, research conducted in Ramshir has shown that participation in training and extension courses has a significant effect on increasing the level of professional knowledge of farmers and farmers' professional knowledge is directly related to age and agricultural work experience (Zare and Zolali 2015). Review of studies confirms the effectiveness of farmers' educational services and shows that there is always a need for education to properly use land and water resources. In this study, farmers' learning and educational resources were first identified. Then, the utilization status of these resources has been evaluated and analyzed separately for irrigation systems (surface and presssurized) and its relationship with the variables of age, level of education and background of using the irrigation system, by statistical tests.

The study area is located in the central latitude and longitude of Qazvin province between 48 degrees and 44 minutes to 50 degrees and 51 minutes east of the Greenwich meridian and 35 degrees and 24 minutes to 36 degrees and 48 minutes north latitude relative to the equator. The total area under cultivation of crops and horticulture in Qazvin province was on average 334.764 thousand hectares, of which about 2323.439 thousand hectares (equivalent to 66.5%) irrigated and about 1112.325 thousand hectares (equivalent to 33.5%) has been rainfed (Anonymous 2019a, Anonymous 2019b). The research method was the Delphi technique and the survey tool was a questionnaire. The score of learning status of learning and educational resources was calculated using the mean index. Kolmogorov and Smirnov tests were used to check the normality of the data. To compare the score of each item with the average Likert scale (3), a one-sample t-test (parametric test) and one-sample sign test (non-parametric) were used. To compare the three perspectives of farmers, experts, and trainers, Kruskal-Wallis (non-parametric) and Mann-Whitney (non-parametric) tests were used. Moreover, Pearson (parametric) and Spearman (non-parametric) tests were used to assess the correlation between the use of learning and educational resources with the variables of age, level of education and background of using the irrigation system.

Evaluations showed that the utilization status of learning and educational resources from three perspectives of "farmers", "experts" and "trainers" has a score of 1.73±1.08, 2.47±0.94, and 1.99±0.79, respectively (out of a total score of 5) for crop farmers with surface irrigation system, 1.98±1.05, 2.52±0.84 and 2.39±0.95 (out of a total score of 5) for crop farmers with pressurized irrigation system, 2.19±1.08, 2.28±0.87 and 2.12±0.96 (out of a total score of 5) for gardeners with surface irrigation system and 2.55±0.92, 2.38±0.88 and 2.37±1.21 (out of a total score of 5) for gardeners with pressurized irrigation system. The results of correlation tests also showed that there was no significant effect on the use of the learning and educational resources of farmers in any of the groups. Background of using the irrigation system only in the group of farmers with a pressurized irrigation system had a positive and significant relationship and the level of education in all groups had a positive and significant effect. The highest use of learning and educational resources based on the three views expressed in the items "experience gained over time" and "benefiting from the experience of other farmers (leading farmers)" versus the lowest use of items related to "computer software and internet by computer", "mobile programs and mobile internet", "brochures, magazines and educational videos", "radio programs" and "attending classes and workshops".

The results of this research showed that farmers have basic knowledge about information and communication technology and are not fully aware of it and participate less in training classes. Also, in general, the utilization status of learning and educational resources from the three perspectives expressed is in the middle to low state. These results showed capacity building and change in content and how to use learning resources and education is necessary according to the conditions, interests, and motivational contexts of farmers. It is also suggested that to provide sustainable education, the provision of support and monitoring services should be considered on an ongoing basis alongside training programs.

The limitation of the country's water resources and the aggravation of this limitation, which is caused by the continuous increase in the demand, has caused the maximum use of the available water resources and the increase in productivity and, as a result, the increase in production per unit area. The present research was conducted with the aim of evaluating the water quality of Dez River in terms of efficiency in pressurized irrigation systems.

For quality assessment of Dez River water in terms of efficiency in pressurized irrigation systems, 7 hydrometric stations were selected including Sepid dashte Sezar, Sepid dashte zaz, Tange pange sezar, Tange pange bakhtiari, Dezful, Harmaleh, and Bamdezh. Qualitative data of Dez River water along a decade (2005-2014) were taken from Khuzestan water and power authority.

The Qualitative analysis using piper diagram showed that water quality in Sepid dashte Sezar, Sepid dashte zaz and Tange pange sezar stations was calcium bicarbonate. Although, in Harmaleh and Bamdezh stations the most of samples were neutral. The results showed that salinity amount was increased from the upstream to the downstream of the river. Whereas, Bamdezh station had low to medium limitation at 95 percent of times for drip irrigation usage. Dez River had no limitation for infiltration due to suitable averages of SAR and EC. Besides, cations and anions coefficient of correlation was variable between 0.67 to 0.78 and -0.249 to 0.6 respectively. Chlorine in the river water from Harmaleh station toward the downstream of the river, had low to medium limitation for sprinkler irrigation usage. The most limitation of bicarbonate was observed at 97.5 percent of times in Sepid dashte Sezar station for using sprinkler irrigation. In addition, sodium amount in Harmaleh and Bamdezh stations compared to Dezful station increased 134 and 233 percent respectively. Langelier Saturation Index (LSI) was negative in the entire stations and calcium carbonate sediment won’t be created.

Maximum sprinkler flow rate, maximum irrigation interval, and leaching requirement are the primary factors in designing sprinkler irrigation systems, which are determined based on the physical and chemical properties of water and soil. This study aimed to prepare the spatial maps of the mentioned parameters in the plains of Islamabad-Gharb district, Kermanshah province. In previous studies, kriging and IDW methods have been found to be suitable for zoning the physical and chemical properties of groundwater and soil. Asadzadeh et al. (2019) investigated the spatial changes of groundwater quality indicators in Ardabil plain by kriging method to investigate the water situation in this area for irrigation systems. Yonesi et al. (2020) also zoned some critical water quality parameters (such as nitrate) of the Najafabad aquifer using the kriging method. Kumar and Sangeetha (2020) used the IDW method to classify groundwater quality in the study area and classify it according to drinking and agricultural uses. Karami and Basirat (2015) evaluated the spatial variations of some surface soil characteristics of Arsanjan plain by kriging and IDW methods. on the other hand, a specific method can not be considered the best method for intermediation and zoning of these parameters. In this study, both methods were used for mediation.

In the present study, to evaluate and analyze social issues and their role in the implementation of pressurized irrigation system on a case-by-case basis in the water intake lands of Khorasane dam in Buchan city in West Azerbaijan province with an area of 400 hectares. The consolidated and aggregated form is considered, paid. The results of the relationship between different variables and effective parameters in social issues showed that the majority of residents of the studied villages are satisfied with the use of pressurized systems. Also, there is a significant relationship between the type of cultivation and irrigation method in the region and according to the results, it can be seen that the most cultivation is related to beets and wheat. Results of the relationship between education and knowledge of the irrigation system There is a significant difference. This difference is due to the grouping of education. In addition, the results of the relationship between education and respondents' income show that there is no significant relationship between education or There is no income with the said items. In other words, the low or high education or income of the respondents has no effect on cultural prejudices.

Allocation of budget to pressurized irrigation projects is supported by the government to manage, saving water resources and increase agricultural production and is considered as the ideal project of the country. Cost-effectiveness and awareness of the cost of an irrigation system is important and necessary for the government. Therefore, estimating the initial and final cost of the project, especially irrigation systems, is one of the project management tools that allow project managers to make more accurate decisions at different stages. Finding a model to identify the important factors affecting the final cost of an irrigation system, as well as formulating it for use throughout the country and regions with different characteristics, is what the present study seeks.

The aim of this study was to estimate the cost of drip irrigation projects in the early stages of design using genetic programming technique, using data from 100 drip irrigation projects, in four sections including; cost of pumping station and central control system (TCP), cost of on-farm equipment (TCF), cost of installation and performing on-farm and pumping station (TCI) and total cost (TCT). First, a database containing 39 important and influential variables on the cost of the mentioned sections was prepared and the prices of the projects were updated for the base year of 2019. In the next step, the most important features that had the highest impact on the costs were selected using Eureqa Formulize software and using genetic programming. In the last stage, different models were presented in each section to estimate the cost and the best model in each section was introduced based on the statistics of accuracy and complexity.

The results of correlation analysis between independent variables and dependent variable (cost of each section) show that in TCP section PP variable (pump power required), in TCF section L16mm variable (total lateral length), in TCI section SR variable (plant row spacing) and in the TCT section, the HP variable (pumping height) with the correlation coefficient (R) equal to 0.766, 0.638, 0.355 and 0.429, respectively, had the highest value among the other variables and all were significant at the level of one percent confidence. Also, the results of cost modeling for drip irrigation system showed that in the TCP section, a model with an evaluation criterion of R equal to 0.449, MAE (average absolute error value) equal to 27236333 Rials and complexity of 22 was the best model. These evaluation criteria for the best model in the TCF section were equal to 0.848, 21198257 Rials and 13, in the TCI section equal to 0.770, 45483996 Rials and 11, and in the TCT section these criteria were 0.743, 77220845 Rials and 15, respectively.

In this study, the cost estimation of different parts of the drip irrigation system was modeled using genetic programming algorithm, and the obtained results showed that the presented models had excellent accuracies in each part. The results of this study can be a very useful tool for researchers, managers, students, consultants, contractors and those who are concerned in the water industry. By conducting similar research, it is possible to make an economic estimate with a high accuracy before the implementation stage. AcknowledgementThis article is extracted from the Ph.D. dissertation, the first author of the article. For this purpose, the authors of the article would like to thank the Department of Irrigation and Reclamation Engineering, Faculty of Agriculture Engineering and Technology, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran for their excellent cooperation, providing the necessary facilities for this research and the preparation of relevant articles. Keywords: Pressurized Irrigation, Cost Estimation, Genetic Algorithm, Feature Selection, Eureqa Formulize.

this study aims to determine the most effective features on the cost of drip irrigation systems in four parts, including the Cost of pumping station and central control system (TCP), Cost of on-farm equipment (TCF), Cost of installation and operation on-farm and pumping station (TCI) and Total cost (TCT). First, data of 100 drip irrigation projects implemented in different parts of the country were collected and it was prepared a database containing 39 important and influential variables in the cost of the mentioned parts. Based on the sensitivity analysis, the best evaluation criteria were obtained in TCP and the numerical amount of gamma statistic, Expected Absolute Error, Gradient statistic, Standard Error of Γ, coefficient of determination (R2), and V-Ratio index were recorded as 0.048, 0.219, 0.008, 0.024, 0.87 and 0.192, respectively, which indicate the high correlation between the experimental variables and the cost of the corresponded sector. To find the optimal combination of data for cost modeling, we used Genetic Algorithm (GA), Hill Climbing (HC), and Full Embedding (FE). The results showed that the number of required variables and the optimal input combination, which covered 40 and 90% of the variables (16 and 35 variables, respectively) in GA and HC method reached 20% in the FE method and only eight variables were selected for cost modeling and also the results of this method were selected as the superior model. Moreover, the result of the hybrid model revealed the simplest and most optimal model was obtained when QT (l/s) (total amount of available water flow), SR (m) (plant row spacing), QE (l/s) (emitter flow), T (h) (number of working hours per day) and NIT (n) (number of irrigation shifts) were used as the optimal input combination to modeling the cost of drip irrigation systems.

Climate change is a challenging topic for irrigation researchers as it has affected crop water demand. In the present study, the effects of climate change on minimum temperature, maximum temperature, precipitation, and the water demand of 12 crops including wheat, alfalfa, potato, barley, garlic, cucumber, watermelon, pumpkin, sugar beet, rapeseed, grain maize, and bean were investigated and also a trend analysis was carried out up to the year 2050. The impacts of implementing and not implementing the irrigation efficiency enhancement, the cropping pattern changes and the development of the early-maturing cultivars as the adaptation strategies in combination with climate change scenarios were investigated between the water years 1399–1428 (2020–2050). The results showed that without implementing the adaptation strategies, the net irrigation water requirement would increase by 3.98% to 8.38% compared with the recorded data. Growth in the irrigation efficiency up to the potential efficiency would cause a 19.23% reduction in the gross irrigation requirement on the average. By implementing the cropping pattern changes strategy through stopping the cultivation of some water-intensive crops such as alfalfa and developing the cultivation of rapeseed, net irrigation water requirement would decrease by 10.9%. By replacing late-maturing potatoes by the early and medium-maturing cultivars and developing of early-maturing grain maze cultivation, net irrigation requirement decreased by 8.86%. Furthermore, the results revealed that implementing all the above-mentioned adaption strategies would reduce the gross irrigation requirement by 34.0%. Hence, the three above-mentioned strategies can be used as the measures that executive managers and farmers choose to implement in order to adapt to climate change.

The water shortage and the recent droughts have revealed the necessity of paying attention on increasing the water productivity, more than done in the past. In this regard, using pressurized irrigation systems is recommended as alternatives for surface irrigation systems. So this study, in order to assess the system performance and water productivity in such systems, nine and ten of the existing sprinkler irrigation systems (constant classic and wheel move) were evaluated in Isfahan and Hamedan Provinces, respectively. The Potential and the actual application efficiency of the low quarter, the distribution uniformity and the Christiansen's coefficient of uniformity were determined. The Averages of PELQ, AELQ, CU and DU in Isfahan province were 61.5%, 58%, 66.8% and 75.8%, respectively and those of Hamedan province were 53.9%, 44.8%, 71.1% and 81.1%, respectively. By determining the average of water consumption and the crop yield, the averages of water productivity in Hamadan and Isfahan provinces were found 6.6kg.m-3 and 6.3kg.m-3, respectively. The averages of water consumption in the irrigated potato fields in Hamadan and Isfahan were 6745 m3/ha and 6298 m3/ha, respectively. The results of this study showed that in most of the studied fields, deficit irrigation has been happened. From the results of these assessments, it can be deduced that the main problems in the implementation of these systems are: inaccuracy of design, the mismatch of design criteria with the implementation phase, incorrect performance, insufficient users' knowledge and the lack of accordance between the amount of water used and the crop water requirement.

Fertigation is the application of fertilizers, soil amendments, or other water soluble products through an irrigation system. Fertigation can be applied for different kind of crops and horticultural plants as well as different types of irrigation systems, including surface and pressurized irrigation systems. Irrigated land in Golestan province is about 200000 hectares that most of them do not use fertigation system. So a research project has been done on the effectiveness of these systems on corn crop in two successive years 2007 and 2008. The experiment was laid out in a randomized complete design where each treatment was replicated three times. Two treatments were 200kg ha -1(N200) and 300 kg ha-1(N300) of pure nitrogen. Amount of considered urea fertilizers were applied through split application twice in two sprinkler and furrow irrigation systems separetly. Crop was SC704 sweet corn that is planted 75 to 20 cm intervals in July after wheat harvesting in the Gorgan agricultural station. During two years of testing, 8 and 7 times irrigation were applied respectively in which two of them accompanied by fertigation. Amount of irrigation water in the first year were 527 and 313 mm for furrow and sprinkler systems respectively and in the second year were 474 and 299 mm. Average grain yield that can be canned in the first year and N200 treatment were 3375 and 4072.3 kg ha-1 and in the second year, were 2637.3 and 4165.3 kg ha-1 for furrow and sprinkler systems respectively. Average grain yield that can be canned at treatment N300 in the first year were equal to 3124.3 and 2930.3 kg ha-1 and in the second year were 2647 and 3278.3 kg ha-1, for furrow and sprinkler systems respectively. The results showed that irrigation method had significant effect at 1% level on yield and yield components. The maximum values of grain yield 4165.3 kg ha-1 from N200 treatment in 2008, cob yield of 8795.6 kg ha-1 from N200 treatment in 200, biomass of 33184.6 kg ha-1 from N200 in 2007 and total dry matter of 7598.3 kg ha-1 from N200 in 2007 has been obtained from sprinkler irrigation that shows the effectiveness of sprinkler fertigation through ventory injector. Different nitrogen fertilizer rates had a significant effect on grain yield and total dry matter at 5% level and maximum grain yield and total dry matter production were obtained in N200 treatment. Different nitrogen fertilizer rates had no significant effect on cob and biomass. In general two years results indicate the effectiveness of fertilizer use efficiency in sprinkler fertigation.

Considering the severe water shortage crisis for producing agricultural products, the concept of real water saving in agriculture has been introduced recently. The reason behind this is that many researchers have realized that many approaches which are used for water saving in agriculture (e.g., improving irrigation efficiency, and even improving agricultural water productivity-WP) rely on the development of modern water-saving irrigation methods such as pressurized irrigation. These systems, when required conditions or relevant context are not fulfilled, may not lead to real water savings and may even cause an increase in water consumption. Examples of these arguments, discussion, and pieces of evidence are provided in the latest book published by FAO. In this analytical paper following explanation of the concepts, terms, the visions on real water saving, and effectiveness of modern irrigation technologies in this regard, all the activities relevant to improving WP, with the objective of water saving in agriculture, are elaborated and discussed. The paper concludes that for the purpose of recognition and selection of technical and economical approaches effective on water demand and use, water accounting framework should be set in a specific basin. Also in parallel to the attention to the development of pressurized irrigation systems in Iran, other approaches and measures, such as agronomic practices for reducing ET in agriculture (e.g. use of mulches, conservation agriculture, and proper crop rotation, etc.) should be selected. Finally, for achieving real water saving, the WP index should be evaluated based on ET and not based on applied water to the field. This should be the necessary criteria in selecting irrigation systems and other measures in regards to their effectiveness on real water savings in agriculture.

Feasibility and evaluation of the most appropriate regions for executing different irrigation systems according to water quantity and quality is of great importance, and prevents energy, credits and resources losses. In this research, using the fuzzy analytical hierarchy process method (FAHP), the possibility of execution of different irrigation systems (surface, sprinkler and drip systems) was evaluated based on the quantity and quality of groundwater in Miandoab plain. In this order, the effective qualitative and quantitative criteria which is needed to execute each of the three irrigation systems were determined and point values for each effective parameter in the decision were interpolated and zoned by geo statistical method. Then by turning of raster data layers into fuzzy mode using fuzzy membership functions and calculating relative importance weights of the criteria using Analytical Hierarchy Process (AHP) method, the above-mentioned layers were combined and the final layer of suitable areas for water harvesting at the three irrigation systems were identified. The zoning maps of Miandoab plain restrictions in different surface and pressurized irrigation systems execution showed that 32.32, 19.02 and 51.89 percent of the total areas of the plain has serious and very high restriction in surface, sprinkler and drip irrigation systems respectively.

Mehran Plain has been accompanied by a drop in groundwater levels in recent decades.The aim of this effort was to study the level of groundwater in Mehran plain using the system dynamics method under different scenarios of crop pattern and pressurized irrigation systems development. the conceptual model was designed, dynamic hypotheses were explained and simulation was performed. After verifying the model, the research purpose was evaluated in terms of applying 12 scenarios consisting of three scenarios for crop pattern and four scenarios of pressurized irrigation systems development. Among the crop patterns scenarios, the replacement of canola instead of alfalfa in crop pattern showed the best result in groundwater level in Mehran Plain. Also, the results of this effort showed that the development pressurized irrigation systems in condition current efficiency not only does not improve the groundwater level, but also has a negative effect on the groundwater level of the plain.