جستجوی مقالات مرتبط با کلیدواژه « برنج » در نشریات گروه « اقتصاد کشاورزی »

In the supply chain of essential grains such as rice, fraud, poor supervision and delay in reaching the product to the final destination, are always among the main challenges of the beneficiaries of these chains. Improving the supply chain monitoring and tracking system is the best solution to reduce discrepancy among business partners and information asymmetry in these chains. Blockchain enables the mapping and visualizing of steps in a supply chain easily because of its interconnected and encompassing bridging of actions. it builds trust among the parties included in a supply chain because it provides open access to key data points it captures. Blockchain encapsulates smart contracts and automatically update actions when predetermined conditions of the actions are met. Since blockchain is a distributed ledger consisting of multiple copies, it is almost impossible to tamper with a specific transaction because one has to alter all the copies simultaneously. Blockchain is also advantageous for ensuring and sustaining consensus over the process because all the parties know that the transactions are automated and valid. The application of blockchain technology in the management of supply chains brings many benefits such as traceability, information security, transparency and trust. The traditionality of the method of monitoring and tracking in the rice supply chain brings serious concerns about fraud and lack of quality assurance. In this situation, it is very difficult to create trust and transparency between the stakeholders of the chain. The application of blockchain technology can be the driver of the transition from the traditional management of the rice supply chain in Iran. Identifying the factors affecting the application of this technology in the supply chain and determining their importance can improve the policy-making process in this field. Considering the importance of rice in the food basket of Iranian households and the existing concerns about safety and issues such as fraud in the supply chain of this product, the present study identifies the drivers influencing the use of blockchain technology in the rice supply chain and also, their prioritization took into account.

This study is applied in terms of purpose and descriptive-survey in terms of research method. The research tool is a pairwise comparison questionnaire based on the objective, criteria and sub-criteria of the decision tree. The decision tree was formed with the aim of identifying and prioritizing the drivers affecting the use of blockchain technology in the rice supply chain, and it includes six criteria and 26 sub-criteria. The findings of previous researches and the opinions of sample experts were used in designing the decision tree. The required information was obtained by completing the pairwise comparison questionnaire by 10 rice market experts in Guilan province during the spring of 2023. In order to analyze the data and determine the relative weight of research criteria and sub-criteria, spherical fuzzy hierarchical analyze was used. This process is carried out in five stages, including creating a decision tree, creating a matrix of paired comparisons using linguistic terms, checking the consistency of the matrix of paired comparisons, calculating fuzzy weights and determining the final rating score of the options. In order to categorize the sub-criteria in terms of the effect intensity, the interval of standard deviation from mean was used.

According to the number of decision tree criteria and sub-criteria, seven comparison groups and 62 pairwise comparisons were analyzed. The validity of the research findings was evaluated using the inconsistency index. The value of the inconsistency index in all comparisons were less than 10%, which indicates the validity of the relative weights. The criteria of "smart contract", "traceability and prevention of fraud" and "simplification of transactions" with a total relative weight of more than 57% are three important criteria according to experts’ comments, respectively. Among the sub-criteria of the smart contract, "increasing the credibility of the rice supply chain" is the most important with a relative weight of 29.52 percent. Regarding the sub-criteria related to "traceability and prevention of fraud" and "simplification of transactions", "quick identification of rice" with a relative weight of 20.30% and "doing payment without the need for a bank" with a relative weight of 24.65% were the most important drivers. Classification of drivers using the interval of standard deviation from mean showed that there are four sub-criteria in the impact category with very high intensity, eight sub-criteria in the impact category with high intensity, 11 sub-criteria in the impact category with low intensity and three sub-criteria in the impact category with very low intensity. Increasing the credibility of the rice supply chain, no need to physical presence in setting up contracts, safe storage of rice supply chain information, and speeding up data transfer in the rice supply chain are sub-criteria with very high impact intensity.

The use of blockchain technology in managing and optimizing the supply chain of agricultural and food products is emphasized by many researchers, operational managers and policy makers. Many challenges in the rice supply chain require promoting the use of new technologies such as blockchain. The findings of this research, including the identification, prioritization and classification of drivers affecting the use of blockchain technology in the rice supply chain, provide a suitable opportunity to formulate a related policy package and operational measures in the supply chain.

In order to meet the increasing demands of the growing population, it is essential to boost rice production. This not only ensures food security but also helps maintain environmental well-being. To achieve these goals, it is crucial for crop management research to focus on increasing rice yields while minimizing water usage. In Iran, particularly in the Rudbar region, recognizing the significance of rice cultivation in agriculture is of utmost importance. To improve rice field management, various aspects such as water and soil resource management, pest and disease control, nutrition management, sales and marketing strategies, human resources and social capital management, as well as technical and agricultural improvements need to be addressed. Therefore, the aim of the present study was to identify more effective methods for managing the rice fields in Rudbar county, Iran.

Materials and Methods:

 Initially, the researchers conducted a comprehensive analysis of available national and international databases to gather background information for the study. This analysis aimed to establish an initial list of components that could contribute to improving the management of rice fields. The statistical population of the study consisted of all 850 rice farmers in Rudbar City. Using the Karjesi-Morgan table, a statistical sample size of 265 participants was estimated, which corresponded to the size of the population. Eventually, 252 questionnaires were collected after distributing them to the participants, resulting in an 88% response rate. The opinions of faculty members from Tehran University's Department of Agricultural Management and Development were sought to assess the content validity of the questionnaire which was finally confirmed. To assess the reliability or internal consistency of the questionnaire, Cronbach's alpha coefficient was calculated for each of its components. All coefficients were found to be above 0.7, indicating good reliability of the study tool. The data obtained from the questionnaires was subjected to statistical analysis using the LISREL 8.8 software. A confirmatory factor analysis model was applied to examine the data. The reliability of the indicators loaded on each structure was evaluated using the t statistic. Indicators with values exceeding the critical limit of 1.96 were considered to have the required precision for measuring the relevant structure. Additionally, significant factor loadings were determined by extracting values greater than 0.5 from the factor loadings. It is important to note that Cronbach's alpha (with values higher than 0.7) was utilized to assess the reliability of the constructs.

The research findings highlighted several significant factors that have a substantial impact on improving the management of rice farms. These factors encompassed various aspects, including water and soil management, human resources and social capital, nutrition management, pest, disease, and weed management, technical and agricultural management, as well as sales and marketing management. Regarding water and soil management, the study emphasized the importance of optimal application of water resources, consideration of water quality, sediment control, and prevention of toxins and sewage from entering rice fields. Given the submerged nature of some rice stalks and the perpetually swampy conditions of rice fields, it is crucial to ensure the quality of incoming water and prevent the presence of mud and sediments. In terms of nutrition management, the research findings stressed the significance of using fertilizers effectively to enhance rice productivity. This involved post-planting strengthening, adherence to appropriate fertilizer consumption guidelines, and the utilization of plant and animal residues. Nutrition management, along with pest and disease control, played a vital role in successful rice field management. Another factor contributing to effective rice field management was the control of pests, diseases, and weeds. The study highlighted the benefits of employing an integrated approach to manage rice plant diseases and pests, which yielded better outcomes. The research findings also emphasized the role of technical and agricultural management in enhancing rice field operations. This included the use of transplanting machinery and improved seeds, mechanization of cultivation activities, and the application of fertilizer spraying machinery. These measures underscored the need for innovation in rice fields, emphasizing the importance of mechanization and the utilization of modern agricultural instruments. It was recommended that rice producers embrace technological advancements to optimize their technical and agricultural practices. Furthermore, the management of human resources and social capital played a significant role in rice field management. This encompassed fostering the growth of social capital, enhancing knowledge and skills, and utilizing mass media for skill and career development. The findings suggested that increasing cooperation, trust, and organization among rice farmers could be a strategy to revive social capital and enhance management practices. Lastly, the study highlighted important features of rice sales and marketing, such as employing an appropriate distribution system, excluding profit-seekers from the marketing cycle, and establishing regular customer relationships. Overall, the research findings emphasized the importance of addressing various factors, including water and soil management, nutrition management, pest and disease control, technical and agricultural management, human resources and social capital, as well as sales and marketing management, in order to effectively manage rice fields. Implementing these strategies would contribute to improved productivity and sustainable management practices in rice cultivation.

The findings of the study indicated the significance of several measures to improve the management of rice fields. These measures included the utilization of additional fertilizers and adherence to fertilizer usage guidelines, as well as the adoption of mechanized planting and harvesting equipment. It was also recommended to provide skill training programs for rice farmers and introduce online marketing platforms to facilitate the sale of rice. Furthermore, the study highlighted the importance of establishing specialized communication channels and implementing a contract system for rice production and sales through dedicated local organizations. This approach would ensure efficient coordination and enhance the management of rice fields. Additionally, private businesses were recognized for introducing new technologies, while the government played a crucial role in providing the necessary infrastructure and platforms to support rice field management. Improving the skills of rice farmers, especially in terms of market innovations, was identified as a key factor in enhancing the management of rice fields. This aspect should be considered alongside institutional and policy-making advancements to ensure comprehensive improvements in rice field management.

small lands are very common in rice farms, which, as economists believe, leads to the lack of optimal use of production resources and consequently increases production costs of rice and its price. Therefore, empirical investigation of economies of size in rice farms is very important for reducing production costs. To achieve purpose of the present study, data on rice production and its costs were collected from 180 farmers in four cities of Guilan province for the 2019-2020 crop year. Using Duality's theory, the cost function and demand functions estimated in three flexible functional forms namely Translog, Normalized Quadratic, and Generalized Leontief. Based on the estimated parameters of the best model, the elasticity of the size was estimated. As well, average cost function of rice production was estimated and based on it, the elasticity of the average cost with respect to the production was calculated.The results show that Translog functional form is the most suitable form for the expression of rice production technology in Guilan province. Results show that structural parameter of “Return to Size” for paddy farms is equal to 1.33 in average and is greater than one for all the observations. As well, elasticity of average cost relative to production is negative for all the farmers. Therefore, estimated models prove the advantage of economies of size and negative slope of average cost function in all rice farms . So, there is no any farm with efficient size in the studied sample and it is possible to reduce the production costs and the cost price of rice by increasing the size of production for all the farms. based on the findings of this research, land integration policies and increasing the size of rice paddies are suggested as an effective strategy to reduce production costs of rice production.

The main purpose of this study was to evaluate the efficiency and technological gap ratio (TGR) of different rice cultivars in Guilan province For this purpose, metafrontier method was used to determine the TGR. The statistical population of the study was all rice farmers in Guilan province in 2017. Sample size was selected by stratified sampling method. The results showed that the mean technical efficiency range of different rice varieties was between 76% and 93%. In fact, if the gap between the farmers in the study is filled. In fact, the average yield of the Hashemi, Domsiah, Ali Kazemi, Jamshidjo, Shiroudi and Khazar could be 47, 7, 23, 12, 8 and 15 present increases respectively. The results also showed that the highest technological gap ratio for the studied varieties was related to Hashemi (0.96) and the lowest technology gap ratio was related to Khazar (0.45). Based on the results income, mechanization index, farmer's main occupation, ownership, experience and land size have a positive and significant effect on farmers' technical efficiency.

In the 2016-2017 crop year, an experiment was conducted in Irandegan, Khash city, Sistan and Baluchestan province under heat stress conditions in a split plot design in randomized complete blocks with three replications to investigate the effect of heat stress on yield and yield components of a number of rice cultivars. The main factor was the use of Shafaq, Shiroodi, Basmati, and Hir cultivars, while the sub-factor was planting on April 9th, April 30th, and May 22nd. According to the results of the analysis of variance, the interaction of cultivar with planting date affected straw weight, flag leaf length, grain weight, 1000-seed weight, grain yield, production efficiency, percentage of inoculated seeds, percentage of hollow seeds, and percentage of gypsum seeds. Plant height and spike length also differed significantly across varieties. In addition, planting date and cultivar had an effect on the quantity of seeds per sike. The highest straw weight (2046.3 g/m2) was obtained on April 30th in the Basmati cultivar, the highest grain yield (5688.7 kg / ha) on May 22nd in the Shafaq cultivar, the highest percentage of inoculated seeds (89.7 percent) on May 22nd in the Hir cultivar, and the highest percentage of gypsum seeds (73.33 percent) on May 22nd in the Basmati cultivar. In the face of heat stress, the Shafaq cultivar maintained a satisfactory yield. According to the findings, the greatest yield is associated with May 22nd, and the best cultivar to suggest growing in the area based on the highest yield is Shafaq.

An experiment Was carried out Study of heat stress on rice cultivars grain milling quality of Khuzestan province in a split-plot arrangement using randomized complete blocks design with three replications in 2006 and 2007 cropping seasons at Shavoor Agricultural Research Station, Dependent in Research Center of Agricultural and Natural Resources of Khuzestan. For exposing rice cultivars to different higher temperature regimes, main plot was assigned to three sowing dates from 5 May with 20 days' intervals and cultivars; Hoveizeh, Hamar (heat tolerance) Ghermez Anbori, Champa (heat sensitive) and Danial (relatively heat tolerant) were randomized in sub-plots. The results of combined analyses showed that was a significant different in planting date by variety interaction in all of trades. On the other hand, the related temperature condition, varieties had different reaction. The highest of grain elongation obtained in Ghermez Anbori, Danial and third sowing date. The elongation ratio was higher in third; second sowing date and Ghermez Anbori. The heat tolerant cultivars had highest Gel consistency (Gc) and Amylose content (Ac). The highest Gelatinization temperature (Gt) obtained in third sowing date.

In order to evaluate of effects, the nitrogen and potash fertilizer on yield, yield components and remobilization on number 4 rice promising line. The study was conducted using a factorial experiment arranged in completely randomized design with three replications at the Rice Research Institute of Iran in 2012. The factors were nitrogen with 3 levels (60, 90 and 120 Kg.h-1) from Urea fertilizer’s resource and Potash fertilizer with 3 levels (0, 50 and 100Kg.h-1) from the sulfate potash resource. Analysis of variance showed that the Nitrogen Factor was significant on all the considered traits at 1 probability levels. The Potash Factor was significant on the grain 1000 weight at 1 probability level. The interaction effect of Nitrogen in Potash on traits the number of filled grain and the grain 1000 weight were showed significant difference at 5 probability levels. The highest of treats seed yield (7818 kg.h-1), the percentage of panicle reproduction (88.47%), grain 1000 weight (30.08g), the number of seed filled (149.4), height plant (110.6 cm) and for remobilization of dry matter (1198g.m-2) were obtained 120 kg. ha-1. Mean comparison effects of Nitrogen in Potash interactive showed that for grain yield of a 120 kg nitrogen per 50kg Potash with the average of 7994 kg h-1 was consider a higher class. Finally, for the number 4 promising line of rice can use a level of fertilizer which includes 120 kg pure Nitrogen (260 kg urea fertilizer) and 50 kg Potash (100 kg super triple phosphate fertilizer) per a hectare.

Identifying the impact of consumption of different inputs on agricultural production helps to provide the right information to the policymaker. This study aimed at estimating the production function of two basic products (irrigated and rainfed wheat, and rice) using the three-dimensional spatial panel pattern (product, province and time). The required information was collected for the 30 provinces of Iran in the period from 2006 to 2018; and according to the selection criteria of the production functions, the translog function was selected as the superior function. Due to spatial effects and diagnostic tests, the spatial correlation model was evaluated as the optimal model. The study results showed that the elasticity of cultivated area, consumption of pesticides, tractors and combine harvesters to the production of irrigated wheat, rainfed wheat and rice products was positive and the elasticity of labor, consumption of seeds and fertilizers to the production of these products was negative; in addition, the elasticity of production inputs did not change significantly over time, and the trend of impacts of the production inputs on the production of the studied products was almost constant. Due to the surplus of labor in the production of these three products, the withdrawal of labor from production in this sector should be on the agenda and more investment should be made in investment factors such as combine harvesters and tractors to increase production so that the country can achieve self- sufficiency.

In order to investigate the adaptation of native rice genotypes to Mazandaran climatic conditions, an experiment was conducted with 30 rice genotypes in a randomized complete block design with four replications in in two regions of Mazandaran province (Amol Rice Research Institute and Sari University of Agricultural Sciences and Natural Resources) during 2016-2017. The results of combined analysis of variance showed that there was a significant difference between the locations of experiment only in terms of panicle length and number of filled and unfilled grains per panicle, while there was a significant difference among genotypes and genotype × environment interaction for all studied traits. Results of correlation coefficients of the traits showed that panicle length, number of filled grains per panicle and number of fertile tillers per hill had a positive and significant correlation with grain yield. For the 30 genotypes studied, three clusters were found that the third cluster genotypes, including Gardeh and Zire Bandpey with higher grain yield in the two studied regions showed more adaptation to Mazandaran climatic conditions.

In order to Assessment of the role of growth reduction factors on some morpho-physiological and yield indicators of rice cultivars an experiment in the year 2018 was conducted as split plot in a randomized complete block design with three replications. Experimentation factors included various rice varieties: Champa, Chermez-anbori and Hoveizeh in the main plot and reducing growth factors include: control (without cutting), consumption of half a liter of medax top in 45 days after planting, cut 65 days after planting to a height of 35 cm and cut 85 days after planting at a height of 35 cm in the subplot was. the results showed difference between levels of reducing growth factors in terms of stem height, panicle number, number of hollow seed per panicle and seed yield were at 1% probability and 1000-seed weight at 5% level. the difference between cultivars in terms of number of hollow seed per panicle at 1% level and 1000 grain weight at 5% probability level. highest number of hollow seed per panicle was in the control and the lowest in the cut 65 days after planting. the highest grain yield was obtained in the application of medax top with average of 4.7 tons/h and the lowest grain yield with average of 3.19 tons/h was obtained by cutting in 85 days after planting. so it can be cut by 65 days after the planting and use of the medax top or using the hoveizeh cultivar to reach the desired results in the region.

In this study, the rice energy efficiency in Golestan was investigated using interval fuzzy (triangular) data envelopment analysis model at different alpha levels in the year 2016-2017. The data required were collected using interviews and completing questionnaire from 286 rice farmers in Golestan province who were selected using simple random sampling. The results showed that at the level of α= 0.25 could be reduce the amount of input energy to 37.99% in upper bound and 1.83 in lower bound without any effect on the output energy (yield). Also, the results showed that at the level α =1 (certainty conditions) two inputs, irrigation water and chemical fertilizer with 33% and 31.2% respectively, and among the types of input energies, non-renewable energies (energy of machinery, chemical fertilizers, pesticides and fossil fuels) with 60% (24117.7 MJ / ha) had the largest share in the production of this product. The use of new technologies in the use of water input such as installing smart meters on various pumps, reducing the consumption of chemical fertilizer by promoting the use of organic fertilizers and proper training in the use of inorganic fertilizers helps a lot to reduce energy consumption in these high-consumption inputs.

Increasing rice production in Iran due to the scarcity of production resources requires increasing productivity. In order to achieve this goal, the land equipping and renovation project has been implemented in the country. Since the most important rice - producing province in Iran is Mazandaran province, the main goal of present study is to analysis the effect of implementing land equipping and renovation project on productivity in paddy fields of Mazandaran province. For this purpose, the required information was collected by filling out a questionnaire from seven cities of Mazandaran province for the crop year 2017-18. The Tornqvist-Theil index was used to calculate the total factor productivity of first cultivation rice. Then, to investigate the factors affecting productivity, linear regression models was estimated using ordinary least squares method. Also, logistic regression model was used to determine factors distinguish between high productivity farmers and low productivity ones in first cultivation rice. The results show that in both linear and logistic models, the variables of land equipping and renovation project, land rent, geographical area (east vs. west of the province), production technology in the form of improved varieties (high yield vs. local) and doing second cultivation, as well as specialization of farmer have had a positive effect on productivity while the scale of production has no effect on productivity. The calculation of the marginal effect based on the Logit model shows that the land equipping and renovation program is one of the most important factors affecting rice productivity so that the implementation of this project have caused to increase probability of achieving a higher than “average productivity of all farmers” up to 28 percent. Based on the results, considering that implementation of land equipping and renovation project has taken many years, it is recommended to pay attention to implement it as soon as possible in other parts of the Mazandarn province.

Since agricultural activities are inherently risky and farmers have to make decisions in such situations, their decision-making in a context of risk depends on their attitude to risk. In other words, different attitudes, cause people making different decisions in similar situations. In this study, it is tried to determine the attitude of farmers in Rasht county about risk based on four inputs of nitrate and phosphate fertilizers, poison and labour using the Safety First Model. The required data was obtained by filling out questionnaires and face to face interview with 221 rice farmers in year1396 using two-stage cluster sampling method. The results of the study indicate that all of rice farmers are intermediate risk averse towards the use of nitrate fertilizers (urea), phosphate fertilizer and poison (herbicide). This type of attitude can lead to the use of more fertilizers and poisons which result in unhealthy crops and environmental pollution. But rice farmers have different attitudes in terms of labour input, with almost 83% of them are risk averse and only about 17% are risk prefer.

Rice is a strategic crop with a strong presence in Iranian household food basket. This study aimed at investigating the consumers' preferences for rice using the choice experiment method and conditional logit model in Rasht city of Iran. The required data were collected through the 149 questionnaires completed from households in 2016. Six attributes of rice and their related levels were considered to describe the changes in rice, including size of rice grain, types of rice packaging, taste of rice, rice producing country, food safety and price attribute. The study results indicated that consumers had the most willingness to pay for local rice, so that each household in Rasht city was willing to pay 61000 IR rials per kg for the local rice. Accordingly, improving the level of education and enhancing the public awareness and knowledge of the rice attributes through the media (particularly, information on organic products and their benefits, the consequences of the use of fertilizers and chemical pesticides as well as the consumption consequences of imported rice) may contribute to support the organic and local rice while to meeting the demand and consumer preferences as well.

Energy subsidy reform effects on various social groups (producers and consumers) have always been a challenging dilemma for policymakers and researchers in agricultural economics. This study aimed at investigating and quantifying the impacts of targeted energy subsidies on the well-being of consumers and producers of rice in Iran using price endogenous mathematical programming model. The results showed that the targeted subsidies for fuel as a very influential factor in the production and marketing of rice could cause a slight decrease in production as well as increases in prices; then, a new equilibrium in the market would be created for this product, so that the social welfare might be reduced due to a reduced consumers’ welfare while indicating a slight increase in the welfare of rice producers. Therefore, the implementation of this policy might create a recession in the rice market. Accordingly, the investment in production technology through the use of improved and high yield seeds and the increase in consumption efficiency by reducing the rice waste were recommended for increasing the production and supply of the products.

Agricultural products market in Iran is facing structural problems with non-competitive and inefficient conditions for trade of agricultural products, which leads to high price fluctuations for these products. Future markets as one of the risk sharing strategies would shift price risk to brokers and intermediaries. So, future markets are considered as one of the best tools for reducing agricultural risk. Designing and implementing future contracts is time-consuming and costly. Therefore, in order to succeed in setting up such contracts, it is essential to pay attention to several main issues consisting selecting the correct commodity for exchange, determining the optimal specification of the future contracts of agricultural products, and the way of decision making and preferences of market participants. Despite the precise design of future contracts, future markets may fail after commencing due to lack of access for farmers, to use these tools. The purpose of this study is to predict future market acceptance by rice farmers in Sari.
To achieve this goal, the positive Mathematical Programming Model (PMP) is used in the simulation of the traditional and future market within the framework of the GAMS software. All required data were derived from statistics provided by the Ministry of Agriculture and Statistical Center of Iran during 2000 to 2015. The objective function of the model was a calibrated objective function which maximizes the actual quantities of farmers' production. But it should be noted that in solving this model, it was assumed that when the future market is launched the decision of the producers regarding the amount of production is not affected and only a part of their product will be offered in the future market, rather than in the traditional market, with the aim of reducing the price risk. Since this assumption does not validate   in the actual operating conditions and it is expected that the producers' decision-making process would also be affected after entering the futures market and trading in this market. The results of simulation of the traditional market showed that the real average of the production, consumption, and net exports respectively were about 1.1663*10+5, 24074.390 and 1.4071*10+5 tone and the total profit of the producers of these products was about 3.7928*10+8 million Rials..
Based on the results of simulation of future market, the real average of the production, Consumption and Net exports equals about 1.4349*10+5, 26199.05 and 1.1729*10+5 tone respectively and the total profit of the producers of these products is about 3.7958*10+8 million Rials. Thus it is expected that after commencing future market for agricultural products, 44% of all rice farmers would sell their product using future contracts.
Therefore producers' decisions are not affected by the level of production and only a part of their product would be offered in the future market instead of the traditional market with the aim of reducing the price risk. In addition to comparing this market to the traditional market, the launch of the future market will increase the production, consumption and net exports about 1.9, 8.8 and 5.6 percent respectively. Due to the strategic condition of the rice product and the suitability of this product to enter the future market, it should be noted that in the process of optimal design of future contracts, without paying attention to all dimensions for launching the upcoming market, this market will not be successful. Therefore, in this study determination of the amount of participation by rice farmers before launching a successful future market for rice crops has been considered. The first stage were simulating conditions before the launch of the future market, named traditional market conditions of rice, and the average real values of production, consumption, net exports and total profit of the producers of this product were estimated in Sari city. Subsequently, with the goal of reducing the price risk, the conditions after launch of the future market were simulated that represent about half of rice producers will be participanting in the upcoming market. Base on the results of this study, it is suggested that the launch of futures markets and transfering process to the Agricultural Commodity Exchange would need cultural and extension courses to understand the benefits of entering this market.

Given the importance of optimizing the use of production factors in order to increase the agricultural production, this study used data envelopment analysis (DEA) model with statistical tolerance in the data to estimate efficiency scores for paddy rice farmers of Goharbaran region of Sari County of Iran in an uncertainty situation. For this purpose, 16 combinations were considered based on the amount of input and output in favorable and unfavorable situations and accordingly, the efficiency scores were analyzed. Required data were collected by questionnaires through interviews with 196 rice producers in the region. The study results showed that average efficiencies in four scenarios including original, optimistic, pessimistic and mean efficiency scores of 16 combinations with tolerance were 0.65, 0.85, 0.53 and 0.76, respectively; and the difference between the results of original and other scenarios showed the importance of consideration of uncertainty in the data. Also, the results showed that more than 87 percent of the farmers were not efficient even in optimistic situation. Therefore, given the fact that the majority of representative farmers had low efficiency scores, it is critical to investigate the causes of the inefficiencies and implement appropriate policies to enhance the farmers' performance. Finally, a number of solutions were suggested as the effective efforts to improve the farmers' efficiency, which included among others, training the farmers to increase their performance as well as optimal use of agricultural lands.

Rice is one of the most important crops and is considered as strategic commodity in many countries of the world, thus it seems necessary to be supported. Guaranteed purchase of crops is the most important policies of the agricultural sector in our country that has been approved in 1999. The government is obliged to support the production of basic agricultural crops by guarantying the purchase of crops including wheat, rice, barley and … every year. So this study investigates the impacts of government policies, such as import, the guaranteed price of rice and Domestic Resource Cost (DRC) on the supply of rice in the period of 1990-2013. The results show that guaranteed prices of rice with a lag has a significant positive effect on the supply of rice with elasticity of 0.2. Rice import also has a negative impact on rice supply and the elasticity this variable is equal to -0.7. DRC index as an indicator of government support for the production of the crops also had a negative impact on rice supply.

Globalization is an inevitable process that one of its consequences is the liberalization of trade and the reduction of protectionism. Trade liberalization causing the heavily interdependent economics of the countries around the world to reduce customs and trade barriers to a minimum level, and make financial transfers between countries easily done. Rice is the most important and strategic crop after wheat and plays a significant role in trade and food security of the world and Iran. Because it provides more than 20% of human total daily calories and Almost two thirds of the world's population depends on rice for food. The total Production of Rice in Iran during 2012-2013 was about 2.3 million ton and about 93% of rice products are yielded in Gilan, Mazandaran, Khuzestan, Golestan and Fars provinces. About 88% of total production of rice in Iran is allocated to domestic consumption while just 12% of goes to the world market. Total consumption of rice in Iran is about 3.2 million ton.   The model that is used in this study is Agricultural sector partial equilibrium model with endogenous prices. The data used in present study are the average of production, consumption, export, import and area under cultivation quantity, which export and import prices for long, medium and short grain rice and import tariffs for two growing years of 2011-12 and 2012-13 are considered. These information are provided from agriculture jihad organization of Iran, Customs Office of the Islamic Republic of Iran and the book of export-import regulations. In current research, at first simple linear demand function is calibrated for long, medium and short grain rice based on demand price elasticity. The supply function involves two parts: domestic supply function and export supply function. The calibration of domestic supply is done by a Maximum Entropy integrated PMP method and calibration of export supply function is based on export supply price elasticity. It should be noted that the demand elasticities used in current study are captured from various studies and the export supply elasticities are taken as unity following Aydın et al (2004). Constraints that are used in the model are comprised of the constraints of area under cultivations, water, chemical fertilizer, variable costs, constraint of commodity balance and constraints of calibration includes area under cultivation and export.   The investigated scenarios are the reduction of import tariffs for rice by 10, 25, 50, 75, 90 and 100 percent. The results of present study showed that The area under cultivation of long and medium grain rice, compared to the base year (2012 and 2013 will decrease about 0.61 and 3.38 percent), in Mazandaran province, about 0.49 and 9.18 percent in Gilan province, about 2.82 and 4.32 percent in Golestan province , about 90 and 0.6 percent in Khuzestan province and about 24.47 and 2.47 in Fars province t. Short grain rice in Golestan province will decrease about 22.93 percent and in Fars province will decrease about 43.33 percent. Generally, with decreasing tariff rates, the long, medium and short grain rice, compared to the base year (2012 and 2013), will decrease about 21.5, 4 and 11.5 percent, respectively. Also, the consumption of long, medium and short grain rice will increase by 0.5, 1.1 and 0.7 percent, respectively. The average import of long, medium and short grain rice will increase by 5, 11 and 33.5 percent, respectively and Exports of long, medium and short grain rice also will increase by about 7.7%, 11.7% and 11.43% as a result of tariff cuts. Also, the net social welfare due to the reduction of rice tariff rates relative to the base year, will increase about 0.2 percent. The average welfare of consumers will increase about 1% and the welfare of producers will decrease about 1.7 percent compared to the base year. Also the welfare of the state will increase about 9.5 percent compared to the base year.   Considering small cultivated pieces of land, the high cost of production, the lack of relative advantage in the production of some types of rice and also the high waste of factories in the country, trade liberalization can be fruitful. Considering the importance of product advantages in producing, exporting and importing as well the best quality of Iranian rice, creating new technologies and new planting methods such as hydroponic cultivation, which leads to increased performance and increased water productivity per unit area, and also planting kinds of rice which have advantages in each province would conclude increasing the welfare of rice producers.