Research Article
M. Hasanshahi
Abstract
Introduction: Agricultural performance depends not only on the availability of physical resources and agricultural technologies, but also on the climate and environmental conditions prevailing on the farm. As the Earth's temperature rises, precipitation has become an unpredictable variable and has led ...
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Introduction: Agricultural performance depends not only on the availability of physical resources and agricultural technologies, but also on the climate and environmental conditions prevailing on the farm. As the Earth's temperature rises, precipitation has become an unpredictable variable and has led to phenomena such as floods, droughts, etc. in addition, such phenomena have created a new sense of uncertainty for farmers with increasing uncertainty about the prediction of the future climate, and have faced producers with new types of climate problems. It is predicted that the frequency and severity of climate change will increase the challenges facing risk management, as atmospheric conditions (sudden and heavy rains, hurricanes, severe changes in air temperature and acid rain) affect the efficiency of production inputs (fertilizer, seed, pesticides, and so on). ...) Influential. Severe climate change during the growing season can cause serious damage to agriculture and affect farmers' decisions to allocate farm inputs and lead to reduced production and efficiency; Therefore, in analyzing the efficiency and financial and physical performance of the farm, in addition to the production inputs, we should also consider the climatic conditions in which the effect of spring rains on the technical efficiency of tomatoes is investigated.
Materials and Methods: Data from the crop year of 1395-1396 and The model used is a Modified Stochastic Production Frontier Approach (MSPF),with changes in the model so that in addition to the physical inputs of production, heavy rainfall during tomato growth and farm restoration costs (partial re-planting, part of the farm damaged by rainfall) Have been added to the the traditional model of Stochastic Production Frontier Approach (SPF) to estimate their impact on technical performance (in conventional models due to the lack of atmospheric variables, the estimated parameters are biased and the correlation between efficiency and bias is neglected and the bias bias causes the farm manager to decide. Conflicts d Wrong resource attribute and failed to make optimal use of resources). In addition, if the explanatory variables in the production function are correlated with the variables affecting technical performance and this correlation is ignored in the estimation of the production function parameters, it leads to biased estimates of the parameters thus avoiding this kind of correlation, Betis and Coeli's one-step approach is used to determine the factors affecting production efficiency, in which the technical efficiency of the fields is related to the socio-economic conditions of the farmers, management skills and demographic characteristics, etc.Eventually the Modified Stochastic Production Frontier Approach have been compared and the results have been compared with the traditional model of Stochastic Production Frontier Approach.
Results: According to the results of the correlation coefficients estimated between production inputs and rainfall and farm repair costs, there is a relatively strong correlation between heavy rainfall, seed rate and labor force. Heavy rains increase the need for labor to compensate and repair the farm. Rainfall is also negatively correlated with pesticides, since it is washed off by rainfall and instead of being absorbed by pesticides, it is washed out and eliminated, and the farmer is aware of this problem and uses less pesticide during heavy rainfall. Precipitation has a negative effect on pests. Rain is positively correlated with fertilizer as expected, as rainfall can absorb fertilizer faster into the soil and root of the plant. Rain is positively associated with seed because heavy rains destroy the transplants and the farmer must re-transplant. Although the relationship between repair costs and rainfall was not positive but significant, it may be because some of the repair costs (more fertilizer, manpower and seed consumption) were in the three inputs. To test the effect of atmospheric factors on production and technical efficiency, the model parameters were estimated once without the presence of these variables and once added to the model. Comparison of the results from the application of these two models confirms that ignoring the atmospheric variables in the estimation of the technical efficiency leads to bias in the estimation parameters. According to another part of the results: 1- Heavy rainfall caused 100% damage to the farm resulting in technical efficiency reduction, 2- Adding atmospheric variables to the model (MSPF pattern), all input coefficients and technical efficiency change This reflects the impact of atmospheric variables on efficiency and production that were overlooked in previous studies. 3. The high technical efficiency difference estimated in the two models means that in the rainless model, the technical efficiency estimates are more biased, 4. Toxins Chemical in the SPF pattern has a significant relationship with production but in the MSPF model, the coefficient of this variable is not significant because it is likely to wash away the heavy pesticide precipitation and eliminate its effects. 5 - Interesting findings of this study Interaction between inputs And there is heavy rainfall so that heavy rainfall not only damages the farm but also reduces the efficiency of other inputssignificant.6- Proper use of inputs can increase technical efficiency by 14%, resulting in a 19% increase in production and an 11.6% decrease in production costs
Conclusion: Atmospheric factors, especially severe and short-term rains, reduce the technical efficiency and tomato production.
Research Article
M. Ronaghi; M.R. Kohansal; M. Ghorbani
Abstract
Introduction: The role of governance is attracting much attention these days and is often considered as a major reason why some countries have experienced faster economic growth than others. A typical definition of governance is the process of making and implementing decisions that affect economic, political ...
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Introduction: The role of governance is attracting much attention these days and is often considered as a major reason why some countries have experienced faster economic growth than others. A typical definition of governance is the process of making and implementing decisions that affect economic, political and social institutions. Much of this idea of governance, or good governance, is related to the functioning of government within a country, but the concept of governance involves more actors than just government. It includes companies, political parties, the military, non-government organizations (both domestic and international) and even influential individuals. All of these structures have an influence on how decisions are made within a country.
Materials and Methods: The agricultural sector plays a major role in human life, but the share of this sector has decreased in the economic development of Iran. So due to economic sanctions and numerous challenges, attention should be paid to agriculture in Iran. In this study, we determine the factors of agricultural governance which can be used to improve Iran’s agricultural sector. We first use the Meta-synthesis method to find the important factors/variables that have been used in the literature to investigate agricultural governance worldwide. Then we present these variables to two Iranian experts who rank the variables on a worldwide basis using the Shannon Entropy method (which is explained later). The variables from the Meta-synthesis analysis are also presented to a selected group of ten Iranian experts. They identify the important variables of agricultural governance in Iran by modifying, adding, and deleting variables from the meta-synthesis. These experts weigh the variables by a Binary Comparison Matrix (which is explained later). Experts are selected by Snowball sampling and they complete their list (and ranking) through Delphi method. Finally, we compare the global agricultural governance variables from the Shannon Entropy method with those from the pairwise comparison matrix using the Fuzzy method.
Results and Discussion: The results from the pairwise comparison matrix in Iran are different from the results of the Meta-synthesis method worldwide. The Meta-synthesis method shows that international policy, group participation, and cooperative companies, and observance standards have the highest importance and rank. However, for the fuzzy analysis the factors of agricultural employment, group participation and cooperative companies have the highest weight in the political, social and environmental areas and the factors of increase production, and financial and capital markets have the highest importance in the economic area.
The group participation and cooperative companies are common in both methods. Group participation and cooperative companies provide a connection between people and government so that popular demands are easily communicated to the government. Group participation refers to an approach toward building accountability that relies on civil engagement – in which ordinary farmers or cooperative companies demand accountability. The role of group participation is not to replace but to complement and enhance public accountability mechanisms. It includes two categories including Formal social participation, which are social participation mechanisms that are formally written in laws and Informal social participation, which are social participation mechanisms which are not written in law. Easy access to financial resources is one of the requirements for investment and development of the agricultural sector. However, due to the characteristics of the agricultural sector in Iran, and the lack of developed agricultural financial markets, this sector faces investment constraints.
The agricultural sector can be one of the sectors which provides meaningful employment for the rural population. This research suggests that increasing agricultural employment is important for improving agricultural governance. Despite having such a large reduction in employment, the agricultural sector still employs three times more than any other sector.
Agricultural production is vitally important to the world. Agriculture is the main source of livelihood for 2.5 billion people in the world, yet the growth of agricultural productivity has stalled. Yields for major grains grow by about 1 percent per year, which is lower than the population growth rate. Given that, expanding the cultivated area is not possibility to meet future needs so increasing agricultural productivity is the only solution to feeding the growing (urbanized) population (who has higher food demand). The use of modern communications methods in extension services can foster adoption of new technologies and promote profitable cultivation among farmers. Increasing productivity among smallholders in developing countries is a crucial instrument to guarantee food security in the long-run (Dethier et al, 2011).
One of the most important worldwide variables of agricultural governance is international policy. The international aspects of agriculture policy have an important role in pursuing the fundamental objectives of governments. For instance, the Common Agricultural Policy of the European Union emphasizes agricultural productivity, as a fair standard of living for farmers, ensuring reasonable prices for consumers, and promoting stability in markets (in particular stabilizing imports and exports) as well as food security (Ciolos, 2012). Another significant variable in agricultural governance worldwide is observance standards. Standards and technical regulations have attracted increasing attention in ongoing regional and global trade policy dialogue as tariff and quota issues seem to assume a declining dimension. With the reduction in the applicability of tariff barriers, the adoption rate of standards as a trade restrictive strategy has increased significantly.
Conclusion: Group participation shows that the introduction of civic engagement into the entire process of allocating, spending and monitoring public resources can help produce significant operational results (improved performance, the introduction of corrective measures) and process outcomes (Institutional, behavioral and relational changes). This can take the form of direct farmer participation in formulating public policy and budgets in the agricultural sector. Participatory policy formulation has become an increasingly common trend, particularly with the introduction of the poverty reduction strategies at the national and community levels driven by development initiatives at the local level. Participatory budget formation usually occurs at the local level, but at higher levels, representatives of the farming community can play an important role in expressing farmers' preferences in setting up and financing budgets.
Research Article
A. Nikoukar; I. Tajnia
Abstract
Introduction: The concept of low-carbon economy postulates the consumption of less natural resources and causing less environmental pollution, while gaining more economic efficiency. According to the concept of low-carbon economy, low carbon agriculture is a specific model of agricultural production ...
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Introduction: The concept of low-carbon economy postulates the consumption of less natural resources and causing less environmental pollution, while gaining more economic efficiency. According to the concept of low-carbon economy, low carbon agriculture is a specific model of agricultural production operations with both the lowest greenhouse gas emissions and maximum economic benefits having which has three characteristics including lower energy consumption, lower greenhouse gas emissions and lower pollution. Therefore, this research studies the approaches to low-carbon agriculture in Iran
Materials and Methods: In this research, energy consumption and consequently economic growth, which is expected to play a role in carbon emissions, other macroeconomic variables such as trade openness and financial development have been used. The estimated model of the research is linear-logarithmic based on Shahzad et al (2017). For this purpose, the ARDL and ECM patterns and the time series data of 1989-2014 have been used in current study. The data related to carbon dioxide emissions and energy consumption have been collected from the energy balance sheet of the Ministry of Energy, The data related to financial development have been collected from World Bank, Value Added of agriculture section Growth Ratio and Trade Openness data have been gathered from Central Bank of the Islamic Republic of Iran. Eviews9 software has been used to analyze the results.
Results and Discussion: Statistically significant impact of energy consumption logarithm and energy consumption logarithm square on carbon dioxide emissions at the level of 1% in the long run has been revealed by the results. The positive amount of energy consumption and negative amount of the square of energy consumption indicates a U-shaped inverted relationship between energy consumption and carbon dioxide emissions. The energy consumption threshold in the agricultural sector is 46.98 million barrels of crude oil, while the actual maximum energy consumption is 50.26 million barrels of crude oil. So the agricultural sector's performance is now above the mentioned level, then it is expected to reduce carbon emissions by technological improvements while increasing energy consumption. The coefficient of financial development variable in the long run is -0.014169. The financial development efficiency index is considered as national development variable which means each one percent of increase in bank credits allocated to the private sector will reduce about 1.02 ton of carbon dioxide. The coefficient of trade openness variable is 0.010443 in long run. Whereas the trade openness index is considered as the ratio of the total value of exports and imports to gross domestic product, so every one percent increase in the volume of exchanges to gross domestic product leads to a 1.01 ton increase in carbon dioxide and pollution which confirms the hypothesis. The growth rate of value added of agriculture section in the long run does not have any effect on carbon dioxide emissions. In the short run, the coefficient of trade openness is 0.00581. In other words, one percent increase in the ratio of international trade to GDP will increase about one ton of carbon dioxide emissions. The growth rate of value added of agriculture section, financial development, and the first lag of financial development in short run have no effect on carbon dioxide emissions.
Conclusion: The results indicated a long-term U-shaped inverted relationship between carbon emissions and energy consumption in this sector. The maximum energy consumption threshold was also equivalent to 46.98 billion barrels of crude oil. At present, performance of the sector is on downward, and carbon emissions are expected to gradually decrease by the technological improvement as energy consumption increases. Higher level of the energy consumption than the threshold level indicates that technology effect dominates the scale and composition effects. The results shows that the growth rate of value added of agriculture section in long and short run did not affect carbon emissions. Moreover, in the long run, financial development has negative effect on carbon emissions while in the short run financial development has no effect on carbon emissions. But the effect of trade openness index on carbon emissions in the long and short run is positive. According to the results of the study, increasing the volume of credits to the private sector will help reduce carbon emissions. It is also proposed to change the pattern of trade considering the environmental advantages and the use of green energy programs to reduce carbon emissions.
Research Article
A. Najafi; A.R. Karbasi; S.H. Mohammadzadeh
Abstract
Introduction: In today's world, there is not a country that can provide all the needs of its society without the products and services of other countries. As a result, exchanging goods and services between countries is based on the relative and absolute advantage. By increasing private sector investment ...
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Introduction: In today's world, there is not a country that can provide all the needs of its society without the products and services of other countries. As a result, exchanging goods and services between countries is based on the relative and absolute advantage. By increasing private sector investment and research on plants breeding in developed countries, intellectual property rights have gained special importance in the seed sector. Regarding Iran as a major country in importing seeds, especially the import of vegetable seeds, it is necessary to study the Factors affecting Seed Import to Iran .The present study seeks to answer the following questions: What are the factors affecting seed import to Iran? What is the implication of intellectual property treaties for Seed Import to Iran? And whether joining to international intellectual property treaties, the aspects related to intellectual property rights which is one of the conditions for joining to World Trade Organization or the acceptance of a new plant protection treaty will increase the seed import to selected countries, including Iran? Data from 10 countries in the period from 2005 to 2016 have been used to answer this question. Selected countries, including Iran and nine other countries with developmental level close to Iran, were able to access the data they needed. These include Azerbaijan, Colombia, Egypt, China, Indonesia, Peru, South Africa, Malaysia, Brazil and Iran.
Materials and Methods: This study used the gravity regression model to investigate the effects of membership in the law of intellectual and commercial law on the seeds of vegetables in Iran. Given the goal of studying the bilateral trade of countries in different years in gravity pattern, using combined data, it is possible to determine the specific trade effects of each pair of countries. But there is no such information about cross-sectional data. In this way, the relationship between other variables at any given time can be measured in a concrete way. In order to determine these factors, panel data including import variables, distance between countries, GDP per capita, population of selected countries, cultivated area, and virtual variables of membership or non-membership in any intellectual property treaties in Trade and conservation of new plant varieties from 2005 to 2016 have been used.
Results and Discussion: According to the results of the Hausman test, random effects method has been used to estimate the model. In Brazil, after joining the new plant protection treaty, imports did not vary much and kept their downward trend. Peru has experienced a significant increase over a short period after joining the new plant protection treaty. Concerning the acceptance of the treaty, the aspects related to intellectual property rights for both Egyptian and Indonesian countries were regarded as an example. In Egypt, the import of vegetable seeds has been very short and temporary. Similarly, there is no significant change in the import of vegetable seeds for Indonesia. The results showed that the distance has a negative and significant effect on seed imports. Gross domestic product and population variables have a positive and significant effect on seed imports. Iran membership in each of the international treaties has a positive and significant effect on the seed imports.
Conclusion: This study examined the factors affecting seed import by Iran and selected countries. The results showed that, as expected, the distance variable with the negative coefficient was significant, which means that by increasing in distance, the amount of seed imports will decrease. Population variable obtained positive and significant coefficients. That denotes that by increase in population of Iran, the amount of seed imports into Iran will increase. The other variables in this study are not significant. The membership variables in each of the treaties, the new plant cultivar conservation treaty, and the aspects related to intellectual property rights treaty are statistically significant with positive coefficient. That means membership in intellectual property treaties has a positive effect on the amount of seed imports and the amount of increase in imports depends on the degree of implementation of the commitments and adherence to the rules of these treaties. Therefore, with regard to the positive effect of joining to international treaties on seed imports, it is suggested that before joining to international treaties strengthening the infrastructure in seed industry and improving the competitiveness of this industry against seed imports should have happened.
Research Article
D. Modhej
Abstract
Introduction: Agriculture is the most important part of Iran economy. The agricultural sector always has an important role in supplying the essential elements of life and human well-being, so utilizing its capabilities is necessary to fulfill the development goals. Because of the growth population, the ...
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Introduction: Agriculture is the most important part of Iran economy. The agricultural sector always has an important role in supplying the essential elements of life and human well-being, so utilizing its capabilities is necessary to fulfill the development goals. Because of the growth population, the food supply is increasing and due to resource constraints, existing resources should be used efficiently to maximize possible production. Therefore, checking the efficiency of agricultural producers can be useful. Dates as one of the horticultural products due to its nutritional properties, and preservation of the environment have a special status in Iranian agriculture. Cultivating dates in Iran, especially in the southwestern regions (Abadan, Khoramshahr, Shadegan), date back to 6,000 years ago. According to the official statistics of the Food and Agriculture Organization (FAO) of United Nations, Iran has the world's first position in terms of date’s cultivation. Iran is ranked in the second place after Egypt in terms of production and exports with 16.5% of the world's exports. Khuzestan province with 37492 hectares of cultivation is one of the most important areas of production dates in the country. According to the official statistics, Khuzestan province by producing 15.2% of one million ton of country's date has the highest production in the country. Unfortunately, in recent years, salinity of water and dust adversely affected the production and quality of dates in Khuzestan province. Evaluating the performance of this product in Khuzestan province due to its importance in terms of cultivation, production and employment is so significant for the economy of the country. The aim of this study is to determine the efficiency of 8 date’s producers in Khuzestan province during the agricultural period 2010-2017.
Materials and Methods: Data Envelopment Analysis (DEA) is a management tool employed to estimate the efficiency of number of decision making units (DMU’s). DEA can be used to calculate the efficiency measures, and has a wide applicability in various service and industry sectors. The first model in DEA was presented in the CCR paper (after Charnes, Cooper and Rhodes1978) to produce the efficiency of DMUs under constant returns to scale (CRS) assumption. Subsequently, Banker et al. (1984) proposed a variable returns to scale version of the CCR model which was named BCC model. Since in real situations, variable returns to scale is more flexible so in this study BCC model is used. Suppose there is a set of n peer DMUs, each using m inputs to produce s outputs and also assume be the input and output vectors for DMUj, respectively, such that and . The input-oriented and output-oriented BCC models evaluate the efficiency of DMU0 by solving the following linear programs respectively:
The choice of input- or output-oriented models depends upon the production process characterizing the firm (i.e. minimize the use of inputs to produce a given level of output or maximize the level of output given levels of the inputs). DEA window analysis is based on a dynamic perspective, regarding the same DMU in different period of time as entirely different DMUs. The benefit of this method is to describe the dynamic change of the efficiency of each DMU comprehensively, both horizontally and vertically. More importantly, the number of DMU is increased in this method; hence, it enhances the discriminating power by increasing the number of DMUs when a limited number of DMUs is available. Consider a set of DMUs in period of time. Every DMU has m kinds of input and s kinds of output. Let denotes the level of input or output for DMU n in t period of time, then input vector and output vector will be presented as:Consider the window starts at the time point of, and the window width is, then input and output matrix of each window will be presented as
The input-oriented BCC model of DEA window problem for is given by solving the following linear program:
Where .And the output-oriented BCC model is as follows:
Discussion of Results and Conclusion: Land area (ha); Water consumption (cubic meters); Animal manure (tons); Labor (person-days); Machinery (Hours); Fertilizer (kg) as well as pesticides (L) are used as indicators of inputs. Meanwhile, Performance (kg) and Gross profit (Rials) are regarded as two output indicators. Since beneficiaries have more control over the inputs than the outputs, the input-oriented DEA windows model is applied to evaluate the efficiencies of 8 date producers in Khozestan province during 2010-2017. By solving 144 models, the average performance of each window and the average annual provide a basis for measuring and comparing the performance of producers. Results showed that two producers were at full technical efficiency level in 2013, moreover none of the producers during 2010-2012 and 2014-2017 were full technically efficient. In period 2010-2012, efficiency of producers had small variation and the average annual efficiency of producers was much higher in comparison with period 2014-2017. Several factors cause the huge difference in performance over these two periods. Among these factors, one can mention dust in Khuzestan province, Dust particles reduce the harvest and the quality of the product. Another reason is the drought of the last two years. Reducing rivers water has made irreparable impacts on the agriculture of the region.
Research Article
M. Mardani; A. Abdeshahi
Abstract
Introduction: Date is one of the strategic and economic horticultural products in Iran due to its important role in gross domestic product, employment and export. Therefore, investigating the efficiency of date producers and trying to improve their efficiency through optimum use of resources have special ...
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Introduction: Date is one of the strategic and economic horticultural products in Iran due to its important role in gross domestic product, employment and export. Therefore, investigating the efficiency of date producers and trying to improve their efficiency through optimum use of resources have special importance. Several techniques are used to evaluate efficiency of decision making units (DMUs). Data Envelopment Analysis (DEA) is recognized as a methodology, widely used to evaluate the relative efficiency of a set of DMUs. Although, DEA is a powerful tool for measuring efficiency, there are some restrictions to be considered. One of the important restrictions involves the sensitivity of DEA to uncertainty of the data in analysis. In this research, the linear robust optimization framework of Bertsimas and Sim (2004) was applied in DEA with uncertain data.
Materials and Methods: Data envelopment analysis (DEA) traditionally assumes that input and output data of different DMUs are measured with precision. However, in many real applications, inputs and outputs are often imprecise. This paper applied a robust data envelopment analysis (RDEA) model using imprecise data represented by uncertain set in estimating the efficiency of date producers. The method is based on the robust optimization approach of Bertsimas and Sim (2004) to seek maximization of efficiency under uncertainty (as does the original DEA model). In this approach, it is possible to alter the degree of conservatism to let decision maker know the trade-off between constraint’s protection and its efficiency. The method incorporates the degree of conservatism in maximum probability bound for constraint violation. 85 date producers were selected by simple random sampling and necessary data were collected by completing a questionnaire.
Results and Discussion: In this section, the results of evaluating date producers are presented which consists of eight inputs and one output. For denoting input and output data uncertainty, ten given maximums of constraint’s violation probability were considered with respect to nominal values: 10%, 20%,…100% (i.e. we used Γ = 0.10, 0.20,…1.00). The results revealed that Gamma value decreases as the probability of constraint violation increases. The RDEA model result showed how efficiency declines as the level of conservatism of solution increases or as the constraint violation probability decreases. According to the method, if all Gammas equal 0, then robust and original DEA models are the same. The most difference between mean of optimal and actual amount of inputs is related to four inputs including machinery, fertilizer, pesticide, and irrigation water in both DEA and RDEA models. In this regard, the government and other relevant authorities should provide producers with extension services to help them optimize inputs. The average technical efficiency for this category of producers is estimated at 90%, and this result indicates a relatively high level of technical knowledge of farmers in using current technologies. In simulating violation probabilities ranging from 0.1 to 1.0 (at a constant the level of ε), percentages of average conformity are quite high.
Conclusion: Evaluating the performance of many activities by a traditional DEA approach requires precise input and output data. However, input and output data in real-world are often imprecise or vague. To deal with imprecise data, this study used a robust optimization approach as a way to quantify imprecise data in DEA models. It is shown that the Bertsimas and Sim (2004) approach can be a useful tool in DEA models without introducing additional complexity into the problem (we called robust data envelopment analysis (RDEA)). A case study of Ahvaz county date producer is presented to illustrate reliability and flexibility of the model. The problem was solved for a range of given uncertainty and constraint violation probability levels using the GAMS software. This case suggests that our approach identifies the tradeoff between levels of conservatism and efficiency. As a result, efficiency decreases as the constraint violation probability increases. Additionally the RDEA approach provides both a deterministic guarantee about the efficiency level of the model, as well as a probabilistic guarantee that is valid for all symmetric distributions.
Research Article
M.A. Roshanfar; H. Amirnejad; H. Najafi Alamdarlo; B. Nazari
Abstract
Introduction: Today, governments have to adopt different policies to offset water scarcity and balance groundwater resources. Among the policies that have been emphasized in this regard, are subsidies and incentive payments to use modern irrigation technology. In Iran, the policy of grants for under ...
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Introduction: Today, governments have to adopt different policies to offset water scarcity and balance groundwater resources. Among the policies that have been emphasized in this regard, are subsidies and incentive payments to use modern irrigation technology. In Iran, the policy of grants for under pressure irrigation systems is mentioned in the budget law of the country. It is generally believed that the implementation of this policy can save water and would lead to the conservation of groundwater resources. But, in practice this issue has not yet been proven. It is generally believed that the implementation of this policy can save water and lead to the conservation of groundwater resources. But, in practice this issue has not yet been proven. So, the Qazvin plain as one of the biggest and the depleting aquifers in Iran is selected as case study.
Materials and Methods: Since, the irrigation water is supplied through the canal in the modern irrigation network area and the agricultural wells in the traditional cultivations, the objective function of the dynamic programming model is considered to maximize the net present value of cultivating in the irrigation network area and the land of Qazvin plain area. The crop yield in the objective function of the model is the functional of the quantity of water available for plant, which is expressed in the quadratic form. The groundwater pumping costs were considered as a function of pump lift. By pumping groundwater, the saturated thickness would decrease in two area. Therefore, the equation of the groundwater balance was formed to allow changes in aquifer stock from one period to another. The components of this equation were considered as the difference in the inflow to the aquifer from the outflow of the aquifer. The maximum groundwater extraction in the model is limited to the natural capacity of pumping from wells and access to the canal water is confined by the long-term average canal water. It is named the first scenario. The upper limit of access to canal water that supplied from combined wells and artificial recharge was simulated according to rainfall variations and then its average long-term value was calculated. For this purpose, the probability of occurrence of dry, normal and wet years was calculated by the standard precipitation index (SPI) using monthly data of 60 years.
Results and Discussion: This paper presents an analytic model of the effectiveness of groundwater conservation policies on irrigated agriculture in Qazvin plain such as grant for under pressure irrigation systems. The results indicated that by increase in the share of grant, the groundwater used per hectare in the modern irrigation system is lower than the flood irrigation system and gradually the modern system is chosen instead of the flood system. With increasing share of grant the yield and net profit will be increased for each crop until the yield reaches saturation. The results showed that in the whole area, by increasing the share of grant, total water consumption and total groundwater are decreasing and so water will be saved. On the other hand, by increasing the share of grant, the deep percolation into the depth decreases. Investigating the groundwater balance showed that in the normal conditions, the increase in the share of grant cause to increase aquifer stock deficit and reduce the groundwater head and saturated thickness. The empirical findings in Qazvin plain showed that the long term average of the aquifer's reservoir volume is decreasing with increasing the share of grants. In the final, the cost effectiveness analysis (CEA) was calculated for total saved water and the aquifer stock to the total amount of government payments.
Conclusion: A review of the effect of grant policy for investing in the modern irrigation systems on the water use was considered efficient on saving water. It means that with increasing the share of grant the overall water saving in the area will increase. But, the implementation of this policy does not conserve groundwater resources. So, for each a million tomans payment, 665 and 598 cubic meters of water are saved, respectively. However, this policy is not effective for the conserve of groundwater resources because in the share of 100% for each a million tomans payment, the aquifer stock is reduced to 2912 cubic meters. As a final remark, it is suggested that grant policy be accompanied by a limitation on groundwater pumping and crop pattern.