درخت حوزه‌های تخصصی

In recent years, the fluctuation in agricultural commodity prices in Iran is increased and thus, accurate forecasting of price change is necessary. In this article, a flexible combined method in modeling monthly prices of beef, lamb and chicken from April 2001 to March 2021, was proposed. In this new method, three different approaches namely simple averaging, discounted and shrinkage methods were effectively used to combine the forecasting outputs of three hybrid methods (MLPANN-GA, MLPANN-PSO and MLPANN-ICA) together. In implementation stage of hybrid methods, based on test and error method, the optimal MLPANN structure was found with 3/2/4–6–1 architectures and the controlling parameters are carefully assigned. The results obtained from three hybrid methods indicate that, based on the RMSE statistical index, the MLPANN-ICA method performs the best when forecasting prices for beef, lamb, and chicken. The outputs of three combination approaches show that the shrinkage method, with a parameter value of K=0.25, achieves the highest prediction accuracy when forecasting prices for these three meats. In summary, the proposed method outperforms the other three hybrid methods overall.

Iran’s agricultural exports have grown significantly in recent years. Cropland products (HS07) have become the second most important group in Iran’s agricultural exports over the last years. However, few studies have investigated the export potentials of cropland products. Therefore, this study aims to determine the main factors of Iran’s cropland products exports and calculate the export efficiency and potential in the trading partners. For this aim, the stochastic frontier gravity model is estimated based on balanced panel data covering 21 importing countries over the period of 2001 to 2021. The results indicated that economic and physical size of importing countries have positive and significant effect on the exports of Iran’s cropland products. In addition, common border between Iran and trading partners and economic sanctions have also positive and significant effect on the cropland products exports, while geographical distance between Iran and importing countries has negatively effects on the exports. The results of export efficiency showed that Iran does not have 100 percent efficiency in any destination market over the period of 2015 to 2021. Iran has an export efficiency of more than 50 percent only in Afghanistan, United Arab Emirates, Canada and Iraq. According to the results, Iran has the highest potential for exports of cropland products in Iraq. Hence, considering the high potentials in neighboring countries and significantly positive effect of common border partners, it is suggested that trading countries with common border like Iraq should be a top priority for the exports of cropland products.