جستجوی مقالات مرتبط با کلیدواژه "irrigation efficiency" در نشریات گروه "اقتصاد کشاورزی"

Water scarcity is a major deterrent to agricultural development. Adopting appropriate policies to sustain this resource has become an important strategic issue in the country. One of the policies implemented in the agricultural sector for sustainable water resources is the policy of changing the pattern of cropping and reducing the level of water crop cultivation based on the pattern and increasing irrigation efficiency. Accordingly, the aim of this study was to determine the effectiveness of gradual reduction of rice cultivation area along with increasing irrigation efficiency on economic and environmental indices in Marvdasht County. For this purpose, a Positive Mathematical Planning Model (PMP) and calibrated based on crop area data for the year 2017-2018 used. The method used for data collection was based on survey, documentary studies and the use of expert opinions and experiences. The results of this study showed that the application of water demand management policies in the context of different scenarios of reducing rice crop area, in spite of the decrease in the economic benefits of the agricultural sector, improves the economic efficiency index of water resources and decreases the water demand. Therefore, in order to stabilize surface and ground water resources in Marvdasht city, it recommend to change the optimum cropping pattern, in order to reduce the cultivation level of water crops and provide farmers with facilities to equip their farms with new irrigation systems.

Iran with a long-term mean annual precipitation of 254 mm (210 mm in short-term of drought period), mean annual potential evaporation of more than 2000 mm, and dominance of arid and semi-arid climates over 85% of its area is located in one of the driest regions of the world. These factors have led to the dependence of most agricultural productions in Iran on the surface water and groundwater. In this article, based on the statistics and documents collected from the reliable sources, the current situation of agricultural water resources and uses in the country has been studied and analyzed. In addition, the adequacy of agricultural water resources under the current and future conditions, the position of the country in terms of water resources and uses in the world, pathology and solutions to get out of the current situation have been studied and analyzed. Examination of available documents shows that despite the increase in irrigation water efficiency and productivity in the field in recent years, lack of attention to climatic and water resources potentials and unplanned development of agricultural lands to meet the food needs of the country's growing population have led to overexploiting the surface water and groundwater resources, and hence, the destruction of aquifers. Reducing water use in agriculture along with increasing agricultural water productivity and implementing groundwater balance plans have been proposed as the key solutions to the existing challenges.

In order to compare the effect of the policy of reducing water extraction from groundwater resources with the policy of increasing irrigation efficiency, on the deficit of groundwater reservoirs, production, net imports, net social benefits and farmers' income in Khorasan Razavi province, five cities including Mashhad, Sabzevar, Neyshabur, Torbat-e Jam and Torbat-e Heydarieh were selected and the effects of these policies were studied using a positive mathematical programming model (PMP_GME).The study of the effect of reducing water extraction showed that although this policy can balance the water extraction and reduce energy consumption by up to 25%, it reduces the production of important crops such as wheat and increases social costs, in particular, reducing farm incomes and increasing imports. So that it will increase social costs by 20-43 percent, and the cost of each cubic meter of saved water will be between 4540 and 6360 Rials. Replacing new systems instead of old at the potential level without increasing the area under cultivation, will reduce the tank's deficit by 94%. Although the closure of unauthorized wells is a legal requirement, its implementation cannot create balance in the water extraction. In order to achieve the desired result, it is necessary to close the unauthorized wells and reduce water extraction permanently from the wells that have a butterfly. Also by providing bank loans and advisory services, farmers helped to increase irrigation efficiency.

Creating water market as an economic solution on one hand, and simultaneously using modern irrigation techniques as a technical solution, in addition to adapting to the existing dehydration conditions, can optimize the pattern of farming and sale of water saved in the market and ultimately lead to increased farm income Gets The results showed that due to the launch of the water market in the region and the increase in the price of irrigation water from 10 to 100 percent, the level of all of the Hashtgerd plain is lower than the base year, and the changes in the pattern of cultivation after the simulation The acceptance of Hashtgerd plain farmers is different in applying the water price increase scenarios for different products. Also, despite the water market and the increase in the price of irrigation water from 10 to 100 percent, it reduces water consumption in the fields of selected products of Hashtgerd plain. By increasing the price of irrigation water, the volume of water consumed for all products of the pattern decreases. The results showed that, following the launch of the water market and rising water prices, at levels of this increase, farmers are moving toward improving irrigation technology and reducing their yields and incomes. However, to some extent, rising water prices, improving irrigation technology with considering the high cost of investing in such systems, they will not justify them, and in this area they resist the change in irrigation system and do the traditional irrigation, but in the range of rising water prices, the tendency towards changing the irrigation method is more modern and the traditional irrigation decreases. The limited water resources will not increase. Overall, the results showed that the effect of the increase in water prices in the conditions of the launch of the water market in 7 scenarios(10,20,30,40,60,80 and 100%), as well as the effect of improving the technology of irrigation method in two scenarios (20% of new methods And 80% of the traditional irrigation method (40% of the new methods and 60% of the traditional irrigation method), and after a combined assessment in 56 states, at best, an increase of revenue of 194.14 million rials will be achieved in the region.

In order to compare the effect of water pricing policy with increasing irrigation efficiency and investment in water and sewage technology, on reducing the deficit of groundwater reservoirs "DGR", production, net imports, net social benefits and income of farmers in Khorasan Razavi province, Five cities including Mashhad, Sabzevar, Neyshabour, Torbat Jam and Torbat Heydarieh were selected and the impact of these policies was studied using a positive mathematical programming model (PMP_GME). The analysis of the effect of rising water prices showed that although this policy has different results in different regions, making it impossible to implement, farmers' income is reduced from 19 to 98 and an average of 63 percent and increases social costs by 50 percent. So that the cost per cubic meter of saved water will be 5750 Rials. By increasing the efficiency of water transmission and distribution and without increasing the area under cultivation, the DGR is reduced by an average of 83%. The farmer's cost will be 300 Rials and the social costs will be 700 Rials per cubic meter. If the total irrigation efficiency is corrected to its potential, the DGR is reduced by 106%. If the increase in efficiency is accompanied by lack of control over the level of crops, although the production increases, but in conditions, the DGR are rising, but on average they fall by 53%. Replacing new systems instead of old and increasing the irrigation efficiency until to potential level without increasing the level of cultivation, reduces the DGR by 94%. But without increasing water application efficiency, only 63% of the DGE is corrected. It is therefore suggested, in place that the efficiency of transmission and distribution of water has increased, government reduce the extraction of ground water, proportional of increase in irrigation efficiency. Also, in critical areas, providing facilities for new irrigation systems be conditional on reducing water harvesting.

For evaluating the operation of two systems of planting wheat in raised bed planting with furrow irrigation in comparison with conventional planting with Flooding irrigation a testing was conducted in year of 2017-18 in Shoushtar township located in north of Khuzestan province. The attendees were conducted which induced type of planting (wet planting, dry planting), planting with line adopting on the mound (fixed furrow-spring furrow) and 3 line of planting on the mound with spaces of 60 and 75 cm in 3 line in the furrow of random complete blocks with 3 replications. Wet planting with the use of line adopting with spring furrow and spaces of 75 cm increased the operation (p< 0/01) in compares with other attendances by 33%. Also, the harvest index showed a meaning full difference on the factor of space between row and type of planting at the type of furrow (p<0/01) the most operation of seed was related with the amount of 5467 kg related to wet planting and 75 cm rows space and use of line adopting with spring furrower and the least operation with the amount of 4133 kg was related to conventional planting. The results of calculations showed that wet planting has 15% more Irrigation efficiency in compares with tool steeling and conventional planting with irrigation efficiency of 2/184 kg /m3 was the least and planting on atmospheric and 75 cm mound with irrigation efficiency with 29% difference. So, planting with wet planting in rows of 75 cm with spring furrow was the most suitable attendance in increasing operation of seed and irrigation efficiency.

Introduction Sustainable use of groundwater resources has been a concern of the past half century. Although a number of countries for many years have considered this issue, in Iran despite experts warning in the past two decades, recently has been highly regarded, especially by public officials. The use of modern irrigation systems by improving water distribution at the level of the farm and reduce the outflow of water from plant availability, improve irrigation efficiency but these systems increase evaporation and transpiration, and even in the event of a reduction of extraction water from wells, may not be effective in balance of the groundwater resources. The government of Islamic Republic of Iran, yearly pay a lot of subsidies (85% of total cost), to increase irrigation efficiency by equipping traditional culture to new irrigation systems. It may increase irrigation efficiency but may not improve balance of the groundwater resources. However, increasing irrigation efficiency in the process of conveyance, distribution, and application of water, improve groundwater balance, and reduce energy consumption, but costs, benefits and its impacts on balance of the groundwater resources are various in each step. so, technical and economic effects of each step and determining the priority of them, were the objectives of this study.
Materials and Methods In order to carry out this study, five cities include Mashhad, Sabzevar, Neyshabour, Torbat-e-jam and Torbat-e-heidarieh were selected. These areas are located in Khorasan Razavi in north east of Iran with average annual rain 200-250 millimeter. The mathematical relationships between extracted water from underground and surface resources and transfer it to farms as well as water influence to groundwater source and the rate of consumption in the fields and orchards were simulated in the excel spreadsheet. Data were collected by using questionnaires and interviews with farmers in the study area in the crop year 2012-2013. Additional data were collected from government documents in ministry of agriculture, energy and regional office. A multi scenario was simulated include 1-Increase the conveyance and distribution efficiency, CDE, to 95 % via transform dirty channel into the pipe. 2-Substitute pressurized irrigation systems instead of traditional system.3-Combining scenario one and two together. 4- Increasing irrigation application efficiency, IAE, to 75% in modern system in scenario three. 5-Increasing irrigation application efficiency, IAE, to 85% in modern systems in scenario three. 6- Execute scenario one and increasing area of irrigation modern systems to dual of initial forecast (only in Sabzevar until 1.5times). These scenarios also evaluated economically. In economic evaluation, increase of yield, between 10-40 percent as 4 scenarios separately, and reduce energy subsidies include increase power price to 2 times, and three kinds of cost price of power was considered.
Results and Discussion Average of CDE were obtained various between 57-78% in study area. The share of agricultural activity in reduce of groundwater source was 20% and most of area was encountered with low irrigation in warm seasons until to 50%. The most impact in creating balance in groundwater resources belonged to increase of CDE by first scenario and was quite economical. The most reduction on groundwater deficit can happen by scenario 5. However, in Torbat-e-jam and Torbat-e-heidarieh, groundwater deficit will continue unless the culture areas are reduced. Increasing IAE, is more effective than developing culture area of the pressurized irrigation systems, CAPIS, for example, in Sabzvar, increasing of IAE by 12% (scenario four), will reduce groundwater deficit 164% but increasing CAPIS, to 50%( scenario 6), will reduce groundwater deficit only 113%. Increasing CAPIS, with 30% increase in yield, make scenario three economical, but increase electrical energy and so, increase national cost by increasing subsidy of energy. First scenario, reduce consumption of electric power, so its benefit cost ratio will increase because reduce government cost but scenario two, increase consumed electrical energy. In the Sabzevar city power consumption in the first scenario was more than 176 million Kilowatt, which reduces farmer's spending by more than 23 billion IRR, But in the second scenario, energy consumption is rising by more than 25 million kilowatts. So, its benefit cost ratio will decrease if government reduce power subsidy. As a result, this scenario without increase of IAE and yield, will not be economical. In all city except Sabzevar with the increasing yield by 20 percent, all scenarios will be economical, also in all city, with omission of the power subsidy, scenario 2 will be uneconomical, so the government is forced to grant subsidies to expand new irrigation systems. The city of Sabzevar, which has the longest route for pipelines (about 42%), requires an initial investment of 695 billion rials, with investment of 1079 billion IRR needed to equip 15342 hectares of land to modern systems. Therefore, the first scenario, although having more economic benefits, requires a relatively small amount of investment as well. Regarding the energy cost of between 680 and 7300 Rls, a number of government payments with the implementation of the first scenario is reduced from 96 to 1263 billion rials yearly, while the total initial capital required to realization of the goal is 695 billion rials, which is estimated at 70 billion rials, annually.
Replacing the irrigation modern systems instead of traditional systems without reducing the gap between the current and potential IAE, had a little impact on the groundwater balance, and to consider energy subsidies, is in conflict to national benefits.
Conclusions Installation of volumetric meters and tubing for water transmission and distribution channels should be used in preference to increase the efficiency of irrigation, reduce energy consumption and water extraction from wells, protection of saving water, and prevention of increase in cultivation. In order to increase the water application efficiency and production, implementation of modern irrigation systems on farms and gardens should be accompanied by adequate supervision and training.