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    Assessing the Socio-Economic and Natural Factors Shaping Türkiye's Virtual Land Trade Balance
    (Mdpi, 2025) Celik, Saliha; Ucak, Harun
    Agricultural trade not only facilitates the exchange of final products but also leads to the indirect transfer of arable land resources involved in their production processes across countries. These indirect flows are commonly referred to in the literature as virtual land flows or virtual land trade. An in-depth understanding of the factors influencing virtual land flows is crucial for both the management of these flows and the sustainable and efficient allocation of limited arable land resources on a global scale. The objective of this study is to identify the key determinants that influence virtual land flows in T & uuml;rkiye's trade of plant-based agricultural products. To achieve this, the virtual land trade balance for T & uuml;rkiye was computed by estimating the import and export volumes of virtual land from 1986 to 2019, based on crop, year, and country-specific yield values. Subsequently, the relationship between T & uuml;rkiye's virtual land trade balance and macroeconomic and environmental variables-such as Gross Domestic Product (GDP), the real effective exchange rate, annual total precipitation, per capita arable land, and fertilizer usage-was investigated using the ARDL bounds testing approach. The findings of this study indicate that the most significant factors influencing T & uuml;rkiye's virtual land flows are per capita arable land endowment and fertilizer usage. This result highlights the strong relationship between virtual land flows and variables related to productivity and natural resource endowment, while also emphasizing the importance of integrating sustainability considerations and environmental impacts into contemporary agricultural policy frameworks. Elucidating the dynamics of virtual land trade is a pivotal step toward ensuring the long-term sustainability of international agricultural trade, as well as the equitable and efficient allocation of arable land resources. Furthermore, it represents a fundamental strategy for global agricultural production, offering critical insights for shaping future agricultural policy and practice at the global level.
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    CHALLANGES AND PROSPECTS FOR TOMATO PRODUCTIVITY IN RESPONSE TO CLIMATIC VARIATIONS: EVIDNECES FROM KHYBER PAKHTUNKHWA-PAKISTAN
    (Balkan Scientific Assoc Agrarian Economists, 2023) Yousaf, Rabbia; Ali, Shahid; Ullah, Irfan; Sha, Syed Attaullah; Ucak, Harun
    Climate change is the momentous and persisting change in the world's temperature, precipitation, humidity, and other climatic variables. This study, therefore estimated the impact of climatic variations on tomato productivity across agro ecological zones of Khyber Pakhtunkhwa, Pakistan. Panel data for 28 years (1991-2018) across the six districts of the agro ecological was used due to availability of data on tomato productivity and climatic variables. Yield of tomato, area, maximum temperature and rainfall were included in the final estimated model. The results indicate that the average maximum temperature and average maximum temperature square have a significant impact on tomato yield. Average maximum temperature has positive coefficient while the average maximum temperature square has a negative coefficient. This demonstrates that, at first, the tomato yield increases as the temperature rises. It reaches the maximum at the critical temperature (34.95 degrees C) but shows a decline once the temperature rises from the critical value.
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    Problems of Development in Poland and Turkey - selected issues problems (regional and rural development)
    (Univ Wismar, 2018) Ucak, Harun; Poplawski, Lukasz
    Considering a lot of states, EU candidates and countries of accession, there are various developmental problems, especially the level of development of rural areas and regions. In this study, the attempt was made to discuss the issue of developmental problems of regions and rural areas at the regional level in two countries, Poland and Turkey, one which is in the EU and the other one EU candidate. The aim of the paper is to present developmental problems of rural areas and regions at the regional level in two countries, Poland and Turkey.
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    The Role of Energy on the Price Volatility of Fruits and Vegetables: Evidence from Turkey
    (Firenze Univ Press, 2022) Ucak, Harun; Yelgen, Esin; Ari, Yakup
    In agricultural economics, fluctuations in food prices and the factors affecting these fluctuations have always been an important research topic. From production to delivery to consumers, the supply chain of agricultural products has a dynamic structure with continuous changes. In this dynamic process, analyzing the intensive use of energy at each stage has gained more importance with its deepening effects in comparison to the past. This study will empirically explore the volatility spillovers between energy price index and fruit-vegetables price index in the period of 2007-2020 in Turkey using the Kanas and Diebold-Yilmaz approaches. According to the results obtained from the Kanas approach in the study, it has been observed that there is a statistically significant volatility spillover from the energy price index to the vegetable price index, whereas there is no statistically significant volatility spillover to the fruit price index. This finding was supported by the results obtained from the Diebold-Yilmaz approach showing that there is a volatility spillover of 13.52% to the vegetable price index and 0.86% to the fruit price index from the energy price index.
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    The volatility connectedness among fertilisers and agricultural crop prices: Evidence from selected main agricultural products
    (Czech Academy Agricultural Sciences, 2022) Ucak, Harun; Ari, Yakup; Yelgen, Esin
    The price of fertiliser, which is one of the most important inputs of agricultural production, has increased significantly in recent years. In this study, we empirically analysed the effect of volatility in fertiliser prices on selected agricultural products by using the Diebold-Yilmaz connectedness approach, which is based on time-varying parameter (TVP) vector auto-regression (VAR). The findings showed that the spread of volatility and the interconnectedness be-tween these variables increased in times of crisis and that the risk pass-through was due to fertiliser prices. However, empirical results showed that the price volatility of phosphate rock and urea was highly correlated to the volatility of other products. Furthermore, we found that sugar, soybean and cotton were the agricultural products most vulner-able to the effects of external shocks.
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    The volatility connectedness between chicken and selected crops
    (Taylor & Francis Ltd, 2024) Ucak, Harun; Yelgen, Esin; Ari, Yakup
    This study focuses on the examination of volatility connectedness between selected agricultural commodities and chicken meat prices. To achieve this, monthly price data for soybeans, maize, wheat, and chicken meat were gathered from January 1990 to January 2023. Commodity volatilities were estimated using EGARCH, revealing the highest average volatility in soybean prices. Nevertheless, the peak volatility value was observed in chicken meat prices. The connectedness of the volatilities was demonstrated through the application of the TVP-VAR-based Diebold-Yilmaz approach. The results showed a Total Connectedness Index of 34.35%, indicating that about one-third of the forecast error variance of the variables arises from their relationships within this network. It was also found that chicken meat and wheat acted as net volatility transmitters, while soybeans and maize served as net receivers. In addition, the data unveiled the strongest bilateral relationship existing between soybeans and maize, and the weakest between chicken meat and wheat. Lastly, the Dynamic Total Connectedness Index proved effective in approximating significant shock and crisis periods that occurred throughout the given timeframe.
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    The volatility connectedness between fertilizers and rice price: evidences from the global major rice-producing countries
    (Springernature, 2024) Ucak, Harun; Ullah, Irfan; Ari, Yakup
    This study examined the volatility connectedness between rice price and selected fertilizer commodity products among global rice-producing countries that are mainly in the Asian and Pacific regions. For this purpose, natural gas, selected fertilizers, rice monthly price data, and commodity volatilities were estimated by exponential weighted moving average (EWMA). Furthermore, the connectedness of the volatilities were demonstrated by applying the TVP-VAR-based Diebold-Yilmaz approach. First, we constructed eight separate networks for each country and then determined the total connectedness index (TCI), net pairwise directional connectedness (NPDC), and pairwise connectedness index (PCI). The average TCI for all countries varied between 40 and 55%. The dynamic TCIs showed that the impact of food price volatility from 2007 to 2008 persisted until 2009. Connectedness across all networks was seen to decline after 2010, dropping to 40% or lower. Upon analyzing bilateral interconnectivity through the lens of the PCI values, a robust connectedness between triple superphosphate fertilizer price volatility and Bangladesh, Brazil, China, and Pakistan was evident. The interconnectedness of urea fertilizer and natural gas volatility with rice price volatility, along with the substitution relationships between other fertilizers, offers valuable information for investors to construct portfolios.
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    VIRTUAL LAND RESOURCES IN TURKİYE'S CROP TRADE
    (Europe Our House, 2023) Celik, Saliha; Ucak, Harun
    Virtual land refers to implicit land resources displaced between countries in the trade of agricultural products. Virtual land flows can be measured using trade volume and country and year -specific yield data of products. This study aims to measure and reveal the long-term changes in virtual land flows in Turkiye's crop trade from 1986 to 2020. The results show that Turkiye's net virtual land imports in crop trade had increased from approximately -670 thousand hectares in 1986 to 7 million hectares in 2020. Turkey's annual average net virtual land import is 1.8 million hectares.
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    Volatility connectedness across global e-commerce stocks
    (Hrvatsko Drustvo Ekonomista, 2024) Ari, Yakup; Kurt, Hakan; Ucak, Harun
    This paper studies the volatility connectedness between the stock prices of e-commerce companies. For that matter, we implement the TVP-VAR-Based connectedness procedure to unearth the dynamic structure of volatilities. This approach helps us to determine the volatility spillover between assets that are risk receivers or risk transmitters. We utilize the daily log-return data of the largest e-commerce companies by market cap. The data set consists of the daily open, close, high, and low prices of stocks between 2019-01-02 and 2022-12-23. We obtain the volatility of stocks using the Garman-Klass range-based approach. The findings reveal that the average total connected index is relatively high by 65.45%, which means that the forecasting error variance in the variables is due to the transmission and connectedness between these variables. Furthermore, net pairwise directional connectedness results evidence that the most dominant stock is Amazon within the network. Ultimately, we find the strongest bilateral volatility interconnectedness to occur between the stocks of Alibaba and Jingdong Mall.
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    Volatility Spillovers Among EAGLE Economies: Insights from Frequency-Based TVP-VAR Connectedness
    (Mdpi, 2025) Ari, Yakup; Kurt, Hakan; Ucak, Harun
    This study aims to reveal the network connectedness between the volatilities of Emerging and Growth-Leading Economies (EAGLEs) stock exchanges with the frequency-based TVP-VAR connectedness approach. Connectedness results were obtained in short (1-5 days) and long (5-inf) period frequencies among the volatilities obtained with the Garman-Klass volatility estimator. According to the dynamic TCI results, connectivity peaked during the COVID-19 and Russia-Ukraine War periods. BVSP is the most dominant transmitter of the network and spreads the most effect to the emerging markets. As a result of the pairwise metrics, SSE has the lowest values and is positioned as a relatively independent market in the network. In particular, SSE has almost no connection with BIST in the short term, while it has a more significant effect on BIST in the long term. Moreover, the connectedness metrics show that MOEX is in a neutral position in the network and is largely affected by its internal dynamics.