مجله تحقیقات اقتصاد کشاورزی
سال چهارم شماره 1 (بهار 1391)

In this study, agricultural sustainability of selected cities of Fars province evaluated with using the model of agricultural sustainability and compromise programming method. In this regard, data were collected from various sources such as Fars province organization of agricultural Jahad and Fars Regional Water Authority in 1385. As the results, cities of the province were classified into three groups, sustainable (including Kazerun, Lamerd, Mamasani and Abadeh cities), relatively sustainable group (including Lar, Eghlid, Firozabad, Fasa, Darab and Arsenjan cities) and unsustainable group (including Marvdasht, Estahban, Shiraz and Jahrom cities). These results indicate that sustainable group with features including groundwater balance, more diversity in crops and low percentage of lands of these cities has 1% organic matter. Furthermore, high nitrate concentration in groundwater, more negative balance of groundwater, less using of efficient irrigation systems, and over using of pesticides and chemical fertilizers are the remarkable features of unsustainable groups.

The main object of this study is to predict electricity consumption of agricultural sector in Iran. To get the objective, time series method of Auto-Regressive Moving Average (ARMA) and artificial neural networks (ANN) were used. Annual data for period of 1967 to 2008 was used. The Mean Absolute Percent Error (MAPE), Root of Mean of Squared Error (RMSE) and Mean Absolute Error (MAE) criteria were used for comparing the ability of different forecasting methods. As the result showed Feed Forward artificial neural network with back proportion algorithm can predict electricity consumption with MAPE equal to 1.02%, while the corresponding value for time series model obtained 1.13 percent. Other criteria also revealed the same result, so, ANN is expected to predict electricity consumption more precise than ARMA model. Therefore, energy ministry may use ANN in future predictions.

Several studies have estimated production function in agriculture. Most of them have used econometric methods. Recently, the heuristic algorithms have been widely in optimization problems. In this study, genetic algorithm (GA) model has been compared with a Auto regressive distributed lag (ARDL) approach to estimate the production function in agriculture. Time series data of value added, labor, energy and capital agriculture sector was used of 1978-2008. Comparing the results of two methods based on two criteria of Root Mean Square Error (RMSE) and Coefficient of Determination (R2), indicated that the genetic algorithm is more efficient than the ARDL approach

Now seems almost impossible, imagine an economy without the use of policy tools and intervention policy makers. So, what is important is cost reduction resulting from the policies and increasing their efficiency. Agricultural sector with other sectors in the domestic economy is dependent, and application and performance macro-economic policies by the government affects on different parts of economic activity in different ways. This study examines the short and long-run effects of changes in macroeconomic variables, including agricultural commodity prices, interest rate, exchange rate, money supply, GDP and subsidies on the Iran's agricultural sector income in a cointegration framework. For this purpose, is used from Johansen Model with annual data for 1976– 2008. Results show that there exist the long-run equilibrium relationships among selected macroeconomic variables and income agricultural sector. Interest rate and exchange rate, that could be expected Theoretically, have in the short and long-run respectively, negative and positive relationship with income agricultural sector. Also, the prices of agricultural commodities and money supply have in the long term negative effect, but in the short term positive effect on income agricultural sector. The results showed that the payment subsidy to the agricultural sector has not significant effect on income farmers.

The type of foreign policy affect on a country's economic variables and exporter surplus. Also, Pistachio is one of the most important export products and studying these markets have an important role on the earnings of exporters. In this study, factors on the export of Iran pistachios were estimated by using the ARDL approach and in Real Exchange and Nominal exchange rate. In this study, volatility of real exchange rate estimated in GARCH (1, 1) model. Result showed that the price elasticity was 1.1 and 1.6 in the real exchange rate and nominal exchange rate models, respectively. Changes in welfare surplus pistachio exporters, according to two types of price elasticity were obtained, fhich showed a surplus of pistachio exporters in the floating exchange rate policy would be much greater. Also, in log run, exchange rate volatility had a negative effect on the export product. Finally, it is suggested that floating exchange rate policy should be adopted, but the volatility of exchange rate must be reduced.

Recognition and measurements of technical and economic indicators is in the initial steps for rational decision-making and planning for the firms producing. Therefore according to the role of milk production and dairy cattle breeding industry in food security and also the role of Tehran province in animal husbandry sector, technical, allocative, economic and scale efficiency of dairy cattle farms in Pakdasht and Rey counties in southern of Tehran province has been investigated. For this purpose, efficiency of industrial dairy cattle breeding farms was evaluated using Data Envelopment Analysis (DEA). Data and information for this research were collected by studying documents, observation and interview procedures. Results calculated efficiency, assumption variable returns to scale and based on input minimization, showed that half of the producers were technically efficient. Although about 51 percent of producers are technically full efficient but allocative and economic efficiency levels, they are not in appropriate status. Although the average level of technical efficiency was 0.93, but the average levels of allocative and economic efficiency were 0.45 and 0.42 respectively. Results showed that, about 40 percent of producers are scale full efficient. Assessing returns to scale results showed that 37 producers had increasing, 2 producers had decreasing and 26 producers had constant returns to scale. Inefficient producers have to decrease consumption of alfalfa, corn silage, concentrate, medicine and health care costs.

The main objective of this paper is to investigate the effect of real exchange rate volatility on export of agricultural sector in Iran over the period 1974-2007. For this purpose, first, the exchange rate volatility index has been estimated using EGARCH(0,1) and then, in an econometrics models, the effect of exchange rate volatility index on export of agricultural sector has been tested.The results of Saikkonen and Lutkepohl co-integration test show that there is at least one co-integration vector between variables of the model. The results of co-integration vector estimation using the FMOLS approach indicate that exchange rate volatility has a significant negative effect on export of agricultural sector. Also, the empirical results show that, in the long- run, the world GDP and Iran’s GDP variables have a significant positive and the export price index has a negative effect on agricultural export. According to this empirical result, to increase the agricultural export in the Iranian economy, the policy makers must be decrease the exchange rate volatility.

Rice as one of the most important consumer items Iranian households and in providing food security of the community plays an important role. Thus, the government in order to market regulation and price control, each year some parts of limited resources allocated to foreign countries to import rice. So, the aim of this study was to investigate the determinants of supply and demand of rice in Iran during the period 1981-2007. In order to estimate the supply and demand of rice in the form of model of Nerlove partial adjustment and dependent of rice demand. According to estimates, the supply response of farmers against price changes are very small and price increase will not have significant effect on the supply of this product, and interventionist government policies (import) in the market; this product has had a negative impact on farmer's production incentives. Also, in the basis of results, the Possible to increase production through increased acreage is almost neutralized; therefore, the increase in production should be focused on increasing yield per hectare. The results also confirm this is to estimate the demand function, People in their consumer behavior pay less attention to the price And decisions to consume more of this product is affected by individual income. Also, factors such as population, people's consumption habits and consumption patterns of individuals involved in the import. Therefore, the increased emphasis on performance per hectare and reform of consumer pattern of rice can also help the country save foreign exchange to food security.

The main purpose of this study was to investigate Iran's comparative advantage in raisin export and the effective factors on it. Time series data from 1961 to 2009 was applied to this investigation. Besides, the comparative advantages of raisin export for the main raisin producer and raisin importer countries were calculated and the results were compared with each other. In order to determine the comparative advantage of Iran in raisin export, three indexes were calculated: Revealed Comparative Advantage (RCA), Revealed Symmetric Comparative Advantage (RSCA) and chi square measure (2). Based on the RCA index, the result indicated frequent fluctuations of the comparative advantage index for Iran which led from a rising trend to a falling trend. Also, comparing the calculated comparative advantages of raisin export for the main producer and exporter countries, it was indicated that the high volume of production and export was not necessarily due to the existence of comparative advantages in these countries. Afterward, the effective factors on the comparative advantage of raisin export were investigated through estimating a vector auto regressive (VAR) model for the period 1961-2008. The results of the estimated model indicated that the variables such as exchange rate, the amount of domestic production, the production rates of competitors and the world export price had positive effects on the comparative advantage of raisin export for Iran while fluctuations in production had a negative effect on it. These results indicate the need to protect domestic production to reduce production fluctuations, increased production and pave the path to export this product.

The purpose of this paper is examination of hen meat farm-retail marketing margin using from rational expectations hypothesis that was referred by Wohlgenant (1985).For implement of this study, used monthly data's real retail price of hen meat and real fresh hen price over the period of 1380 to1389. Estimation Results of reduce-form show that fresh hen price with one and three lags increase hen meat marketing margin and with two lags decrease it. Also, Results of structural-form show that inventory-to-sales ratio affected marketing margin of hen meat but real interest rate hasnt effectively on it. Therefore for reduce of meal prices undulation, should be make suitable and standard stores