Original Article
Irrigation network management
Tayebeh Kordestani; Elham Darvishi
Abstract
Introduction
The concept of resilience is particularly important in water distribution networks, which are important urban infrastructures. Estimating and evaluating resilience in each network at the time of designing will reduce damage to subscribers and the network. In this research, relationships ...
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Introduction
The concept of resilience is particularly important in water distribution networks, which are important urban infrastructures. Estimating and evaluating resilience in each network at the time of designing will reduce damage to subscribers and the network. In this research, relationships and functions related to resilience (GRA) in water supply systems and solutions for how to increase resilience using two scenarios of pipe failure and additional needs for the Kangavar network were investigated and implemented.
Material and Method
By modeling the initial failure modes by increasing the stress intensity and estimating the consequences that arise, the resilience of a system can be evaluated, which includes the following steps (Diao et al., 2016):
Step 1. Identify the failure mode to evaluate (eg structural failure, excessive demand).
Step 2. Determining the system stress associated with the failure mode and its simulation method (for example, WDS simulation with an additional load on a node for a certain period).
Step 3. Identify the appropriate system and how to measure it (eg ratio of unsatisfied demand to total required demand during the failure period).
Step 4: Simulating the consequences of the failure mode at increasing stress intensity (0%-100% of maximum stress). While stress intensities up to 100% may be highly undesirable, they are theoretically possible and should be considered if a wide range of potential effects are identified. For each given stress value, the appropriate number of failure scenarios is determined.
Step 5. Creating a stress-resilience curve that shows the average, maximum, and minimum results produced by the simulation for each given stress value.
Results
The worst situation for Kangavar network starts at 89% failure and remains until 100% pipe failure. In large networks like the Kangavar network, the graph of the strain duration and the stress duration have a steep slope just like the supply shortage graph. For example, for the value of five percent pipe failure, all three values of minimum, average and maximum strain duration are equal to five. That is, when only five percent of Kangavar's pipes fail, the duration of the strain reaches its maximum.
Among the prevention ways to reduce the lack of supply in case of pipe failure, adding parallel pipes for pipes with a more important position, compared to other pipes or looping the network in different areas of the network. For the Kangavar network, 38 pipes were added to the network. These pipes were mostly parallel to the pipes coming out of the tank. After adding only 38 pipes to the network, the amount of supply shortfall was greatly reduced.
The state of excess demand is actually a state in which a number of certain nodes have a need or demand more than their defined capacity in a certain period of time. This situation is actually very similar to when a fire occurs in the network, except that in the case of a fire, the normal and usual demand of the network may decrease a little. But in this simulation, in addition to the normal need and demand, additional needs are also considered.
Figure 12 shows the duration of the fire for hours 18 to 21. In this period of time, in the worst case, i.e. in 100% of the nodes with higher demand, the network faces only 10.82% supply shortage. This means that if all eleven selected points in the network have additional needs at the same time, the network will have an approximately 11% supply shortage. In this situation, it can be seen that the stress applied to the network occurs at the same moment and the duration of the strain is six hours.
Conclusions
The results showed that the duration of the strain increased with the increase in the percentage of pipe failure. But the graph related to the start of strain had a downward trend and approached zero with the increase in the percentage of pipe failure. The level of resilience for a network is different in different scenarios, in fact it is possible in with equal failure percentage, and the network has more resilience in one scenario than in another scenario. With a slight increase in the percentage of pipe failure in some water supply networks, the amount of strain increases greatly. While in other networks, even with a large increase in failure percentage, the size of the slope strain has started to increase slightly. One of the most important reasons for this depends on the type of network design. For example, if the water supply network is defined as a loop, in case of failure of one of the pipes, part of the lack of demand will be supplied by other pipes. Adding new pipes to the network was one of the solutions considered to increase the resilience of the network in this research.
Original Article
Irrigation network management
amir nourjou; Farid Feizolahpour
Abstract
Extended Abstract
Introduction
Due to the location of Iran in arid and semi-arid regions and according to the quantitative and qualitative limitations of water resources, optimal management and volumetric delivery of water is important in irrigation and drainage networks. In this regard, it is necessary ...
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Extended Abstract
Introduction
Due to the location of Iran in arid and semi-arid regions and according to the quantitative and qualitative limitations of water resources, optimal management and volumetric delivery of water is important in irrigation and drainage networks. In this regard, it is necessary to estimate the water requirement of crops accurately and to provide adequate water to farmers. Remote sensing technology provides facilities that can be used to obtain different layers of information at the lowest cost in the fastest time. Accordingly, many researchers have used remote sensing data to monitor vegetation cover, provide land use maps, estimate crop evapotranspiration and have declared this technology as appropriate tool for such studies. Based on the previous studies, it is observed that low researches has been conducted to investigate the crop evapotranspiration considering the crop water requirement. Therefore, the most important aims of this study are as follows: providing the cropping pattern and land use maps using Sentinel 2 satellite images, determination of the water requirement for the delivery points of irrigation network, determination of the actual evapotranspiration of the crop cover using SEBAL algorithm and Landsat 8’s images, and evaluation of the water supply and management in the Mahabad irrigation and drainage network.
Methodology
In order to determine the cropping pattern of the Mahabad irrigation and drainage network, Sentinel 2 images have been used related to the 2018-2019 cropping year. The images were examined in terms of the region of syudy and the percentage of cloudiness and after selecting the appropriate images, pre-processing operations including radiometric and atmospheric corrections were applied on them. Then, the NDVI index was calculated based on selected images. After determination of the classes, the phenological cycle of crops were examined for each class and spectral pattern of crops was determined during the growing season. Training samples were selected for supervised classification using the existing maps, Google Earth images, creating images with false color composites and considering the growth pattern and some of them were also considered for validation of the classified map. Then, the cropping pattern map was obtained by using the SVM classification algorithm. After generating the crop classification map, the water requirement of the different classes was determined based on the Penman-Monteith evapotranspiration method, applying plant coefficients and irrigation application efficiency at the volumetric water delivery points. Finally, the actual evapotranspiration rate of the study area calculated based on the SEBAL algorithm and compared with the net water requirement map.
Results and Discussion
Based on the results, kappa coefficient and overall accuracy of the classified map were determined to be 0.953 and 91%, respectively. The area of the planted agricultural farms was equal to 10594 hectares and 1576 hectares of farms were without planting. The area of orchard farms was equal to 6786 hectares and the area of sugar beet, wheat, alfalfa and corn lands were 998, 1839, 693 and 278 hectares, respectively. Thus, the net irrigation water requirement was equal to 71 million cubic meters and the gross irrigation water requirement was calculated equal to 161.36 million cubic meters, considering the irrigation efficiency of 44%. On the other hand, the evaluation of the SEBAL evapotranspiration maps during the growing season indicated that the total amount of evapotranspiration was equal to 79.78 million cubic meters, and this amount was 14% higher than the net irrigation water requirement. Finally, according to the crop classification map and based on the comparison of the net irrigation water requirement and evapotranspiration maps, the water consumption in the Mahabad irrigation and drainage network was evaluated. It turned out that in the upstream farms of the network or close to the Mahabad River, the Water consumption was more than net water requirement and downstream areas were faced to deficit irrigation due to lack of sufficient water.
Conclusions
Based on the results of this study, it was observed that by using the capabilities of satellite images and remote sensing, it is possible to monitor and evaluate the condition of agricultural farms on a large scale with acceptable accuracy. Also it is possible to improve the management of water supply and water use efficiency in irrigation and drainage networks by creating up-to-date land use maps, determining net and gross irrigation water requirement and comparing with actual evapotranspiration maps.
Original Article
Pressurized Irrigation Systems
Elham Zanganeh-Yusefabadi; Akbar Karimi; Ali Sheini-Dashtegol; Abedali Naseri; Shaban Zarei
Abstract
Extended Abstract
Accumulation of solutes in the surface layer of soil is one of the challenges of subsurface drip irrigation, especially in arid and semi-arid regions. This study was carried out in order to investigate soil salinity and sodicity in two experimental fields of subsurface drip irrigation ...
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Extended Abstract
Accumulation of solutes in the surface layer of soil is one of the challenges of subsurface drip irrigation, especially in arid and semi-arid regions. This study was carried out in order to investigate soil salinity and sodicity in two experimental fields of subsurface drip irrigation (with a drip irrigation depth of 20 cm) and furrow irrigation located in the Khuzestan Hakim-Farabi Agro-Industry. In this study, the changes in soil salinity at the depths of 0-30, 30-60, and 60-90 cm and sodium absorption ratio (SAR) in the surface layer (0-30 cm) were investigated during the growth period of sugarcane (2 (T1), 4 (T2), 6 (T3), 8 (T4), 10 (T5) and 12 (T6) months after the start of irrigation). The average data were compared using the t-test at the 5% probability level. The results indicated that the soil electrical conductivity (EC) at both the depths of 0-30 and 30-60 cm, in all the times, except for 2 (T1) and 10 (T5) months after the start of irrigation (surface irrigation + subsurface drip field), was significantly affected by the irrigation method. The highest difference between the soil EC in the subsurface drip irrigation field and the furrow irrigation field was recorded at the T3 and T4 sampling times. In these sampling times the average soil EC in the subsurface drip irrigation field at a depth of 0-30 cm was 1.47 and 1.98 times greater than that of furrow irrigation field. In all the sampling times, except for T5, the soil SAR at depth of the 0-30 cm, in the subsurface drip irrigation field, was significantly higher than that in the furrow irrigation field; and in the T5 sampling time, it was significantly lower than that in the farrow irrigation. At the T5 sampling time, surface irrigation in the sub-surface drip irrigation field led to leaching of accumulated salts in the surface layer of the soil and reduced the soil SAR. The highest of soil SAR (13.1) value in subsurface drip irrigation field was related to T4 sampling time. Therefore, it seems that besides using a subsurface drip irrigation system in arid and semi-arid regions, it is necessary to provide the possibility of surface irrigation in order to manage soil salinity and sodicity.
Introduction
In arid and semi-arid regions, optimal use of water resources and management of soil resources is necessary to achieve sustainable agriculture. Accumulation of solutes in the surface layer of the soil is one of the challenges of subsurface drip irrigation, especially in arid and semi-arid regions. In the drip irrigation system, the distribution and accumulation of soluble soil salts in the surface layer of the soil is more than that in the deeper layers and it increases with increasing distance from the drippers. Soil salinity in the subsurface drip irrigation method should not be ignored, because in this irrigation method, even in good water quality conditions, some amount of water is transferred to the soil and the salt concentration on the soil surface gradually increases. Therefore, it is necessary to monitor and control the soil salinity in subsurface drip irrigation conditions. This study was carried out in order to investigate the soil salinity and sodicity status under subsurface drip irrigation and furrow irrigation during sugarcane growth period.
Methodology
This study was carried out in two experimental fields of subsurface drip irrigation (with a drip irrigation depth of 20 cm) and furrow irrigation located in the Khuzestan Hakim-Farabi Agro-Industry. In this study, the changes in soil salinity at the depths of 0-30, 30-60, and 60-90 cm and sodium absorption ratio (SAR) in the surface layer (0-30 cm) were investigated during the growth period of sugarcane (2 (T1), 4 (T2), 6 (T3), 8 (T4), 10 (T5) and 12 (T6) months after the start of irrigation). The average data were compared using the t-test at the 5% probability level.
Results and Discussion
The results showed that at all sampling times, electrical conductivity (EC), concentration of soluble cations (Na, Ca and Mg) and SAR of the soil in the subsurface drip irrigation field were more than the furrow irrigation field. The results indicated that the soil electrical conductivity (EC) at both the depths of 0-30 and 30-60 cm, in all investigated times except 2 and 10 months after the start of irrigation (surface irrigation in subsurface drip field), was significantly affected by the irrigation method. The results of this research showed that in all sampling times of salinity, the concentration of soluble cations (Na, Ca and Mg) and SAR of the soil in the subsurface drip irrigation field was higher than that in the furrow irrigation field. The greatest difference in the soluble concentration of Na, Ca and Mg in the soil in the two studied fields was related to the T4 (8 months after cultivation). At this sampling time, the average soil soluble concentration of Na, Ca and Mg in the subsurface drip irrigation field was 2.1, 1.95 and 1.93 times their values in the furrow irrigation field, respectively. In all sampling times except T5, the soil SAR at the 0-30 cm depth, in the subsurface drip irrigation field, was significantly higher than in the furrow irrigation field, and in T5 sampling time, it was significantly lower than farrow irrigation. At the T5 sampling time, surface irrigation in the sub-surface drip irrigation field led to leaching of accumulated salts especially Na in the surface layer of the soil and reduced the soil SAR.
Conclusions
According to the results of this study, it seems that besides using a subsurface drip irrigation systems in arid and semi-arid regions (like Khuzestan Province), it is necessary to provide the possibility of surface irrigation in order to manage soil salinity and sodicity. Moreover, considering that sugarcane is a perennial plant, it is necessary to pay attention to soil solute leaching in order to control salinity in the management of sugarcane fields.
Acknowledgement
The authors of the article thank and appreciate the Khuzestan Sugarcane Research and Training Institute for their financial support and assistance in the various stages of this research.
Original Article
Irrigation network management
Ali Afruzi; Farshid Taran
Abstract
Extended Abstract
Introduction
Snow is an important source for water supply in the agricultural sector, electricity production, groundwater reserves, and rivers. This natural resource is important since it stores water in winter with low demand and releases it in hot seasons with high demand. Melted ...
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Extended Abstract
Introduction
Snow is an important source for water supply in the agricultural sector, electricity production, groundwater reserves, and rivers. This natural resource is important since it stores water in winter with low demand and releases it in hot seasons with high demand. Melted snow flow can be very useful in low-water seasons. In arid and semi-arid regions, snow is considered a basic source of fresh water. Significant spatiotemporal changes in distribution of snow on the scale of a basin can be important in determining the time and amount of snow melting in spring. These changes can increase the probability of drought and runoff. Therefore, snow cover plays an important role in the study of hydrological processes and climate changes. Snow cover is sensitive to temperature and environmental changes and can be a good indicator for local and global climate changes. The lack of sufficient and correct information about snow reserves can lead to inappropriate use of water resulting from snow melting and, as a result, irreparable damages. Therefore, measuring the surface covered by snow and its water equivalent, along with other information such as snow density, especially in areas where snow accounts for a large share of precipitation, is essential for resource planning and management. However, it is not possible to measure it in many areas due to harsh environmental conditions. Also, the data measured at one point cannot be generalized to a wide area of a basin. Thus, the use of satellite images can be considered as one of the methods of investigating spatial and temporal changes in distribution of snow in a region. The use of these images is much more economical and efficient, compared to the point data of ground stations, due to the high coverage and the ability to take pictures of an area at different times with high accuracy.
Hamadan is one of the provinces with a lot of snowfall in Iran, whose economy is largely dependent on agriculture, and snowfall plays a significant role in supplying the water needed for agriculture and drinking. However, there is no research on the temporal changes of snow cover in this province and its relation with changes in important climatic parameters such as temperature and precipitation. Considering the effect of climate change on changes in snowfall over time, the aim of this study was to investigate the temporal distribution of snow cover in the province of Hamedan during 1982-2023. For this purpose, the data of snow cover, snow depth and snow water equivalent in different months of the year were estimated using satellite images obtained from the FLDAS product. Then, the increasing or decreasing trend of these data was determined. Finally, their correlation with meteorological parameters of temperature and precipitation was obtained.
Materials and methods
To obtain the monthly values of snow cover (SC), snow water equivalent (SWE) and snow depth (SDepth) from January 1982 to December 2023, the FLDAS (Famine Early Warning Systems Network—FEWS NET—Land Data Assimilation System) product from the Noah 3.6.1 Land Surface model was used. This product is at latitude 90° to -60° and longitude 180° to -180° with a spatial resolution of 0.1°×0.1° in netCDF format and its images are available monthly from January 1982 until now.
The non-parametric Mann-Kendall test was used to investigate the increasing, decreasing or constant trend of the data during specific time intervals in the period. The Theil-Sen slope was used to calculate the slope of the trends. The correlation of the temporal distribution of snow cover with the two meteorological parameters of temperature and precipitation was determined using the Pearson's method.
Results and discussion
The results showed that the year 1982 with a total of 41043.04 km2 had the highest and the year 2021 with a total of 4048.12 km2 had the lowest SC. These data indicated a 90.13 percent decrease in SC in 42 years, which is understandable considering the 35.08 percent increase in the mean temperature (from 9.49 to 12.82 ºC) in this period. The monthly average of SC in this period showed that there was no snow cover from May to October, and in April and November it was very insignificant and negligible compared to in January, February, March and December. Among these four months, January had the highest average SC.
According to the Mann-Kendall test, the trends of SC, SWE and SDepth was decreasing in all the four months of January, February, March and December. Temperature and precipitation values had increasing and decreasing trends, respectively.
According to the Theil-Sen slope test, SC had the steepest and gentlest decreasing slope in January and December, respectively. In the case of SWE and SDepth, the steepest decreasing slope was related to February, and the gentlest decreasing slope occurred in December. The increase in temperature had the gentlest slope in the two consecutive months of December and January, and the steepest slope in the two consecutive months of February and March. The steepest and gentlest slope of decrease in precipitation occurred in March and February, respectively.
The Pearson's correlation coefficient values indicated that SC, SWE and SDepth had inverse correlation with temperature and direct correlation with precipitation. Overall, SC, SWE, and SDepth were more correlated with temperature than with precipitation, especially in February and March when temperature was higher than in December and January.
Conclusion
In this study, using the satellite images obtained from the FLDAS product, the data of snow cover, snow water equivalent and snow depth were obtained in the province of Hamedan for the 42-year period of 1982-2023. The results showed a significant decrease in the snow cover during this period, which was expected due to the climate change and temperature increase. The snow cover, snow water equivalent and snow depth had decreasing trends. The trends of the two climatic parameters, temperature and precipitation, were increasing and decreasing, respectively. The steepest and gentlest slope of the decrease in snow cover occurred in January and December, respectively. There was an inverse correlation of snow cover, snow water equivalent and snow depth with temperature, and a direct correlation with precipitation. In general, the correlation of snowfall parameters with temperature, especially in warmer months, was more than their correlation with precipitation.
Original Article
Pressurized Irrigation Systems
REZA BAHRAMLOO; Abolfazl Nasseri; Mohammad Mehdi Nakhjavanimoghaddam; Ali Ghadami; Nader Abbassi
Abstract
Extended Abstract
Introduction
Potato is a plant with a lot of nutritional value that is cultivated and produced in more than 150 countries of the world. Potato production of this product is increasing, due to the high adaptability to different climate conditions in the world. The annual global production ...
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Extended Abstract
Introduction
Potato is a plant with a lot of nutritional value that is cultivated and produced in more than 150 countries of the world. Potato production of this product is increasing, due to the high adaptability to different climate conditions in the world. The annual global production of potato is 310 million ton, which is obtained from 23 million ha of agricultural land in the world. The cultivated area of potato in Iran in the crop year of 2017-2018 was 154000 ha with the production of more than 5 million tons. In total, 55% of the cultivated area and about 60% of the annual production belong to Hamedan, Ardabil, Isfahan, Kordestan, East Azarbaijan and Lorestan provinces. Studies on the effect of planting patterns on yield and water productivity in potato production have a long history at the international and national levels. It is difficult to draw general conclusions and recommendations for the application of appropriate treatments due to the differences in treatments and research findings. Therefore, the objective of this study was to apply a meta-analysis approach to summarize the results of several investigations on the effect of planting patterns on yield and water productivity in potato production.
Methodology
Several scientific papers published by international and national researchers on potato planting patterns were reviewed, screened, and analyzed. Control and experimental treatments have been applied in studies on the investigation of the effect of planting patterns on yield and water productivity in potato production. The spacing of potato planting rows in different experiments including 60, 75, 120, and 150 cm has been reported as a single-row and/or two-row under drip and/or sprinkler irrigation systems.
The steps of meta-analysis are briefly described below.
A) The intensity of relationships between variables cannot be determined by statistics or statistical tests. Therefore, it is necessary to apply effect measurement indicators. One of these indicators is the effect ratio index (R). The effect ratio (R) is obtained from the ratio of the average traits measured in the research treatment to the average traits in the control treatment. These traits included yield and water productivity in potato production.
B) The percentage of changes in the traits resulting from the experimental treatment (CH %) compared to the control treatment is obtained from the following relationship:
Results and Discussion
The average yield of potatoes was 33000 kg ha-1 and water productivity was 5.46 kg m-3 in the control treatment with row spacing of 75 cm. The combined results showed that increased yield by changing the planting spacing from 75 cm to 60 cm 33%, to 120 cm 18%, and to 150 cm 8%, respectively. While the application of planting spacing treatments on water productivity was not statistically significant. Minor positive effects were observed compared to the effect of the control treatment. The highest positive effect was in the planting spacing of 60 cm (10%). Changes in yield and water productivity in two-row cultivations compared to single-row under the drip system decreased by 7%, while increased yield and water productivity were 4.6% and 16% under the sprinkler system, respectively.
Conclusion
The findings on the effect of planting patterns on yield and water productivity in potato production, have a lot of diversity and variance results. Therefore, the optimal planting patterns in potato production has not been determined. Meta-analysis, as a powerful approach, has led to precise findings to integrate the findings of planting patterns researches under different irrigation systems. In this study, statistical comparisons were made between potato planting rows from 60, 75, 120 and 150 cm as one and two- row under drip and sprinkle irrigation systems based on potato yield and water productivity. In the control treatment with row spacing of 75 cm, the yield and water productivity averaged 33000 kg ha-1 and 5.46 kg m-3, respectively. The findings showed that the increase in yield by changing the distance from 75 cm to 60 cm was reported by 33%, to 120 cm by 18% and to 150 cm by 8%. The effect of planting distance treatments on water productivity was not statistically significant. However, partial positive effects were observed compared to the control treatment. The highest positive effect (10%) was in distance of 60 cm. Changes in yield and water productivity in two-row patterns compared to one- row with drip system decreased by 7% and with sprinkle system, yield increased by 4.6% and water productivity by 16%.
technical paper
Irrigation network management
Alireza Esmaili Falak; Fariborz Abbasi
Abstract
Abstract
Nowadays, the world has different features than in the past, including intense and competitive changes, low adaptability, complexities, and uncertainties. The agricultural sector, as a major food producer worldwide, is not exempt from these traits, and, according to scientific reports and predictions, ...
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Abstract
Nowadays, the world has different features than in the past, including intense and competitive changes, low adaptability, complexities, and uncertainties. The agricultural sector, as a major food producer worldwide, is not exempt from these traits, and, according to scientific reports and predictions, these changes are expected to become more prominent and challenging by 2050. Climate change and limitations of agricultural production resources (especially water and soil), along with other issues such as population growth and aging, urbanization and decreased willingness to work in the agricultural sector, economic issues and changing in supply and demand patterns, have led to food security in human societies with new and even turbulent conditions. In order to manage and overcome this challenge, Future Studies tools based on Megatrends review has been noticed in recent decades in different countries and international communities. Since Iran is also among the countries most vulnerable to the effects of climate change and is more or less affected by other factors limiting the agricultural sector, this article examined six of the most effective global megatrends related to water, soil and agriculture by 2050, and compared the position of the Islamic Republic of Iran towards the world and other countries. Finally, with the aim of enumerating the future-oriented solutions of climate change, it was suggested that, through convergence and constructive interaction, the development of a comprehensive national plan should be proposed and supported as an important priority, in accordance with the approach of increasing resilience and adaptation to climate change and water resources reduction.
Introduction
Food security is one of the main pillars of the sustainable development of countries, and dealing with the threats of food insecurity should be considered as one of the major goals of the development plans of all countries. According to the concerns that exist in this field, governments try to use the results of future studies to obtain information so that they can become an active element (instead of an observer), and interact with the future as a decision-maker to be able to take action some preventive measures. The most important "Megatrends" that are directly and indirectly involved in the food and agriculture sector, include demographic changes, economic changes, urbanization and migration, technological changes, climate changes and competition for production resources. In order to study 6 major megatrends and compare statistics and information related to the past, present and future, many articles, official reports, annual statistics and the results of documented forecasts were used. The world population will reach about 9.7 billion people in 2050, and about 97% of this growth will be in developing countries. The world's working population in the agricultural sector has decreased from 40% in 2000 to 27% in 2022. By 2050, about 82% of Iran's population will live in cities. Significant economic changes will take place in the world by 2050 in terms of per capita income and GDP. Global warming and climate change will have a significant impact on agricultural processes, such as reducing water resources, water and soil salinity, reducing crop yields, floods and droughts events, etc. In terms of access to water and soil resources for food production, restrictions with different degrees and intensities are seen almost all over the world. Therefore, this article attempts to provide a general description of the situation and challenges by 2050, through collecting, analyzing and comparing information and data related to effective global megatrends in the water, soil and agriculture sector of Iran and the world. However, we believe that the researchers should be more involved in future studies concepts because it is necessary to clarify more details of water and soil issues and their integration with other agricultural areas in the future to provide the basis of national sustainable development approaches. In this technical note, in order to at describing and forecasting the effective factors in the water, soil, and agriculture sectors until 2050, six majors global Megatrends have been identified. In each of these Megatrends, the status, potential challenges, and Iran's position in the world have been compared and evaluated based on statistics and information from scientific sources and official international reports, including FAO, World Bank, and IMF. Finally, considering the experiences, predicted results in the examined trends, and discussions held with experts, suggestions and solutions aligned with the country's conditions have been presented.
Results and Discussion
Review of the effective trends in the water, soil, and agriculture sectors, as well as the predicted outcomes related to each of the major global trends, particularly "climate change" and "competition over production resources," clearly indicates that the challenges facing agricultural production and food security in societies are emerging and intensifying in many parts of the world, including Iran. In addition to the direct impact of each of the studied trends on the quality and quantity of water and soil resources, the indirect effects, especially the interrelated impacts of these factors, are also crucial and could be noted as in future relevant research. While it is expected that some of these deficiencies may be addressed through new technologies and unforeseen developments, planning and action within the frameworks of "mitigation" and "adaptation" are undoubtedly indispensable. In this regard, some countries, with a proper understanding of the conditions and precise policymaking, have formulated strategic plans and roadmaps aligned with the mentioned principles, and have achieved successes accordingly. In Iran, although a brief reference to climate change issue in the Seventh Development Plan, considering the over 93% dependency of agricultural production on water, as well as other serious threats in terms of soil salinity and erosion, it is essential to develop a national strategic document to address climate change, consisting of probable scenarios and national priorities. Furthermore, since the supply of 80% of the world's surplus food until 2050 depends on the increase in yield and productivity, it is necessary for these aforementioned strategies to receive more attention in the country's food security policies. In this regard, improving irrigation efficiency and developing modern irrigation methods are highlighted as crucial and fundamental approaches in enhancing climate change resilience and sustainable development of water and soil resources. Fortunately, the technical capacity and the ability of implementing modern irrigation projects in Iran are up to 250 thousand hectares per year, and therefore it is suggested that planning and more support for the conversion of remaining irrigated lands (about 5/5 million ha) should be paid attention to by policymakers, because by completing this project, it would be possible to save more than 5 billion cubic meters of water per year. Noteworthy is the anticipated urban population growth in Iran (up to 82% by 2050) and also to enhance productivity and ensure investments, it is advisable for government support in the development of modern irrigation systems and other water and soil infrastructure to be directed towards large-scale agricultural projects in agricultural hubs. It is crucial to emphasize that maximizing the use of international capacities and opportunities is undoubtedly a prerequisite for success in each of the projects and programs, and in this regard, based on past experiences and achievements, it is recommended to expand technical cooperation with relevant organizations such as FAO and global projects like GSP (Global Soil Partnership), WaPor (FAO Water Productivity Open-access portal), AQUASTAT (FAO's Global Information System on Water and Agriculture), AQUA CROP (Crop-water productivity model), etc.
