فصلنامه اقتصاد کشاورزی
سال چهاردهم شماره 4 (زمستان 1399)

The aim of this study was to investigate the influence of households’ time preferences on their willingness to pay a price premium for organic rice over conventional rice in Shiraz. A fourteen-item Consideration of Future Consequences (CFC) scale was used to extract consumers time preferences. The consumers' willingness to pay was extracted based on single–bounded dichotomous choice contingent valuation method. The design of the bid price vector and the allocation of the sample between different values of this vector were made based on the criterion of minimizing the variance of willingness to pay applying the Cooper method. The required data were collected in June 2018 by completing 536 questionnaires from Shirazian citizens. Data analysis was performed using the censored normal regression model. Based on the results, the effect of consumers time preferences on their willingness to pay a premium price for organic rice was estimated to be significant and positive, so that they are willing to pay premium to buy organic rice. The interaction of education level and time preferences variables was significantly positive at 1% level. This suggests that by taking into account fixed level of the individuals' time preferences, consumers with a college education are willing to have a higher price premium than those without a college education. Therefore, assuming that university education leads to improve environmental insights, increasing public knowledge to protect the environment through public media with the aim of stimulating demand for organic and pro-environmental products, should be considered by policy makers.

Moran test confirmed the spatial dependence in observation distributed around countries. Hence, the meta-regression is combined by spatial approach for all three equations. Results show: i) decrease in difference between control and treated groups in recent years since improvement in household’s food security condition due to policies as FAO confirmed as well and improvement in quality of studies; ii) using logit model to determine propensity score makes higher difference between control and treated groups in compare of probit model; iii) financial program does not improve food security condition of treated groups because financial program regardless complementary program such as environmental protection, irrigation, non-farm income and improved seeds could not improve food security index as expressed by Stamoulis & Zezza (2003) and Thomas & Strauss (1997). Suggestions: Therefore, it is strongly suggested that the priority of Asian and African developing countries to avoid food insecurity should be stressed on a set of pro-poor program including improvement of access to food and measures to development of agriculture. Also, considering balance between enhancing household’s income and facilitating acceptance of technology in farming systems. Results of investigation can be ensured in survey studies applying PSM by using a specific welfare indicator rather than pillared indicators.

Humans in all ages have faced a problem limited resources and production facilities So that even in the current situation and with the increasing development of science and technology, it is still limited to the available facilities. Therefore, higher productivity and efficient use of available facilities has practically gone beyond a choice and become a necessity. Therefore, the productivity growth of wheat crop in the regions of Fars province during the period 2013-2018 has been studied by Spatial-Stochastic Frontier Analysis. For this purpose, first the Translog cost function is estimated by using the collected data for the studied time period. Then, using the results of model estimation, total productivity growth of production factors is divided into two components: technology change and scale effect. The results show that the total productivity growth of wheat production factors in Fars province has been grown by an average of 0.029, and the impact of the direct effects of productivity growth average is more than its indirect effects. The share of the effect of scale in total productivity growth is greater than the share of technological change, the average growth rate of technology change and the effect of the scale are obtained -0.002 and 0.031. The mismatch between the average growth rate of the scale effect and the change in technology has led to a slight increase in productivity. Therefore, according to the findings, it is recommended to take an effective step to remove the major obstacles of new technologies by integrating lands or land preparation to enable production at the optimal level and achieve the desired level of productivity growth.

The agricultural sector is one of the most important and main economic sectors of Afghanistan to improve the situation of poverty, unemployment and food insecurity in this country. On the other hand, due to the nature of production regions, the adoption of regional policies is necessary for the growth of the agricultural sector. Also, major studies show that in the field of investigating the factors affecting growth, ignoring the issue of spatial dependence of areas on each other, will lead to bias and inefficient estimates and incorrect results. Therefore, the aim of the present study is to determine and explain the spatial dependence by considering the effects of spatial overflow on the growth of the agricultural sector in the economic-agricultural areas of Afghanistan using static and dynamic panel spatial models. For this purpose, economic-agricultural areas of Afghanistan have been determined and after confirming the existence of positive spatial correlation using diagnostic statistics and first-order spatial autoregression model, Spatial correlation between agricultural sector growth in these areas evaluated in the form of spatial errors model (SEM) as well as static and dynamic spatial autoregressive model (SAR) as the final model. In the estimation models for the period, 2001-2019 to the role of other effective factors such as the amount of government investment and international support, price index, the role of human capital and specific ethnic, religious and spatial characteristics of each the area was also considered and the direct and indirect effects of each factor were extracted. According to the obtained results, the necessity of using spatial models in agricultural sector policy-making and also the importance of continuing to support the agricultural sector of Afghanistan are emphasized.

in the present study evaluation of the effects of greenhouse gas emissions on the yield and cropping pattern of selected products in Tehran province were investigated. In order to assess the potential effects of drought, global warming and the establishment of local or regional water markets. To achieve this goal, first using general circulation models (GCM) the effects of greenhouse gases on the average climatic variables of temperature and precipitation under the emission scenarios A1B, A2 and B1 were investigated. This was done with the help of GCM/RCM data system and LARS-WG microscale model. Then, using econometric approach and regression analysis, the effects of climatic variables of temperature and precipitation on the average yield of selected products were evaluated. A positive mathematical programming (PMP) model to investigate changes of products yields on cropping patterns was used. The results showed that the behavior of climatic variables of temperature and precipitation during the future periods in Tehran province compared to the base period will increase (0/27 to 3/75 °c) and decrease (0/63 to 41/1 mm) respectively. Increasing the farmers’ desire to develop the acreage of irrigated wheat, corn and canola and reducing the acreage of irrigated barley, tomato, watermelon and sunflower in the cropping patterns of of Tehran province is an important result of application of integrated climate scenario (2 °c increase in temperature and 20 mm decrease in precipitation) in this study. Under the terms of climate change occurrence, watermelon and sunflower with the most decreasing changes in yield (13/1 and 17/7 %) and acreage (68/8 and 31/9 %) as the most sensitive products in cropping pattern of Tehran province were identified. Therefore, planning to reduce or develop the their acrage in the cropping pattern of Tehran province is recommended to farmers and relevant officials in the agricultural sector during future periods.

Iran has limited water resources, and more than 90% of its water is used in the agriculture sector. Virtual water exchange plan is a suitable method to optimize water consumption in the agricultural sector. Attention to water resources, economic factors, technology and transportation, society, and the environment is necessary to examine the suitability of virtual water exchange plans between regions. To do that, this study using the principal component analysis (PCA) method, and an integrated water-ecosystem- economy index has been constructed that includes the indicators of resources, technology, and transportation, economy, society, and environment. The suitability of the virtual water exchange plan in wheat, barley, and paddy products for each province has been investigated based on an integrated index. The results show that Kermanshah, Ilam, and Fars are good and North Khorasan and Golestan are weak for the exchange of virtual water of wheat. In the barley, Chaharmahal Bakhtiari has a good condition, and Khorasan Razavi has a weak condition. For paddy, Mazandaran has a good, and Gilan and Golestan have a weak condition.