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Abstract Background and Objective: Water and soil resources protecting in agriculture has particular importance. This study attempts to determine optimal crop patterns in Firozabad plain taking to account agriculture sustainability with three objectives. For this purpose, utilizing Fuzzy mathematical programming, profit-maximizing as the economic goal and reduction in water, fertilizer and pesticides uses as environmental goals were considered. Materials and Methods: Deficit irrigation and water stress conditions, as well as the adoption of an appropriate irrigation system, was modeled with different decided variables to show the actual conditions of the plain in normal and drought years, by considering the upper and lower targets in the fuzzy model. Results: Results showed that all the three objectives contribute approximately the same levels of satisfaction and there are no clear differences between crop patterns with and without dry farming. In the case of drought years, wheat 25, wheat 49, barley 44, corn 3, sugar beet 48 and rice, and the same products with different levels of deficit irrigations were recommended in the normal year. Optimal crop pattern was determined and comparing it with the average crop pattern in the past 10-year in the region. Conclusion: To align with sustainable agriculture and protecting water and soil resources in Firozabad plain, it is not necessary to change the crop pattern of the area. The main difference is due to choose of an irrigation system, irrigation time, and changing the share of plains cultivation levels to products suitable.

In recent years, due to excessive consumption and unbalance between water consumption and water resources, Iran has led to a severe shortage of renewable water sources. Therefore, in this situation, analyzing the status and presenting appropriate strategies is the main priority for policymakers. For this purpose, by designing a dynamic stochastic general equilibrium model, status of consumption of water resources has been studied in the household, agriculture and industry sectors. The existence and definite status of the stable situation, both parametric and numerically, has been investigated according to estimated values for Iran's economic parameters. According to the results of the research, it should be noted that at present, per capita water consumption is 1000 cubic meters per year. In other words, with current domestic consumption per capita, water per capita is less than that on the optimal Path. It is expected to achieve sustainable equilibrium in a long-term horizons by reforming consumption and providing policy solutions. Also, based on the simulation, from different policies, Establishing a 8-year limit on agricultural products with high water consumption is the most important policy for achieving the above equilibrium.

Intervening government and performing environmental policies are among solutions for reducing production externalities and achieving sustainable development. Indeed, institutional quality is an effective factor in selecting optimal environment policies. This paper tries to identify optimal environmental policy among common public tools for intervening (pollution taxes and permits) in the presence of environmental and economic uncertainties with various institutional quality degrees. In this paper, institutional quality is included in a dynamic stochastic general equilibrium model and its effect on choosing environmental policy is considered. The results showed that pollution permit is preferred to taxation on pollution with various institutional quality degrees. In addition, with improvement in institutional quality, if only shock is an environmental shocks, then taxation on pollution will be an optimal policy.

The growing demand for water and the declining trend in renewable water resources in most regions has led to serious limitations on water availability calling for the sustainable management of the harvestable resources. This has, in turn, encouraged most planners in the water sector to focus on demand management. A number of tools are already available for realizing water demand management goals; one such tool is establishing a water market. The present study is designed and implemented in two stages to investigate the role of a water market in water resources management. In the first stage, the creation of a water market at the farm and basin levels is simulated using a mathematical planning model. The second stage involves the investigation of the combined effects of the water market and water extraction rationing policies. It is found that rationing policies lead to reduced extractions from groundwater resources. The two-stage random cluster sampling method is used to collect the required data. Pilot villages are selected based on the data obtained from the first sampling stage. Pilot farms are then selected in the second stage based on water availability in each place. The input-output data, quantities of available water, and any other data required are finally collected through interviews with local farmers. Results reveal that the volume of exchanged water accounts for 9.5% of the total water consumed and the average improvement gained in farmers’ income ranges from 15 to as high as 42%. This clearly provides enough incentives for the farmers to enter the water market. Like all other water saving policies and measures, establishing a water market might increase consumption, contrary to the national objectives, in the absence of proper supplementary preventive measures. Thus, a second scenario is designed to investigate the combined effects of both water extraction rationing and water marketing. According to this scenario, the total annual irrigation water allocations to the representative farms in groups 1 and 2 are reduced by 20 and 30%, respectively, to observe reductions in farmers’ income levels of only 8 to 11%. This indicates that the simultaneous implementation of both water extraction rationing and water marketing is able to guarantee reductions in water consumption without any considerable decline in farm income levels. The water thus saved can then be used for groundwater protective measures and environmental water allocations. Water meters and volumetric water delivery systems as components of a sound water bookkeeping system considerable at both farm and basin levels will form the prerequisite measures to any water saving policies such as water marketing.

The main purpose of this paper is to determine the amount of subsidy required to promote the share of renewable energy in total electricity production. To do so, different scenarios have been studied by a hybrid approach of Computable General Equilibrium model. The results have been created by entering the details of technology-specific information for electricity generation into this model. The result of codification and calibration of the model shows that in the case of applying same subsidy to achieve 10 present shares of renewable energies in total electricity production, there is a need for 851 percent subsidy rate. Although in this case the wind energy is the only activated resource and the solar and biogas sections have not succeeded in achieving any rise in production rate. The other scenario was based on the unequal subsidy, proportional to disadvantage of different renewable energy. The result shows that, to achieve a balance growth of 4 percent energy productions from renewable sources, the rate of subsidy for wind energy should be 887 present. This rate for solar is 1776 present and for biogas is 1585 present. So, in the first scenario, the proper tariff for purchase of electricity from renewable energy is 4100 Rials per kWh. This tariff in the second scenario is 4260, 8520 and 7600 Rials per kWh respectively.

Computable general equilibrium (CGE) models have become a standard tool of empirical economic analysis and were extensively used to assess the impact of trade liberalization by policy analysts. In this study, the effects of imports tariff reduction as a trade liberalization index are investigated on key economic variables using computable general equilibrium approach. The data used in this study are obtained from the social accounting matrix of year 2001 in which parameters of model are calibrated accordingly. Results of simulations show that if the imports tariff rate is cut by 50% and 100% across all sectors, total supply and investment will reduce while total exports, total imports, household income and consumption will increase.

Since Iran is one of the most important countries in producing as well as exporting pistachio and dates Therefore, in this study after calculating exchange rate volatility using the criterion of standard deviation of exchange rate moving average, the effects of this volatility on the export supply of mentioned crops was investigated. Autoregressive distributed lag model, one of the co-integration analysis methods, was used to reach the aim. Export supply function of pistachio to German, Unit Kingdom and Italy and export supply of dates to German, Unit Kingdom and Turkey were estimated. The results indicated that exchange rate volatility has different effects on export of the crops to understudy countries. Therefore in relation to trade policies, the effect of exchange rate volatility on trade should be considered with respect to destined country.