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Management & Economics
- An analysis of the production-support effects of crop insurance: Evidence from garlic and onion
- Suhwan Lee, Byung Min Soon
- This study examines the production-support effects of crop insurance using garlic and onion as case studies. Crop insurance reduces production risks from …
- This study examines the production-support effects of crop insurance using garlic and onion as case studies. Crop insurance reduces production risks from natural disasters and stabilizes farm income, thereby influencing farmers’ production decisions. Because garlic and onion have substitution relationships in cultivation, the introduction of crop insurance for one crop may also affect the supply decisions of the other. To analyze these interactions, this study estimates acreage response functions, demand functions, and price transmission equations using annual data from 1991 to 2024. The estimated parameters are incorporated into a partial equilibrium model to simulate market outcomes under alternative policy scenarios. Three scenarios are considered: (1) no crop insurance for garlic, (2) no crop insurance for onion, and (3) no crop insurance for both crops. The results show that crop insurance contributes to stabilizing production by supporting cultivated acreage. When crop insurance is absent, acreage and production decline, leading to higher farm-gate and retail prices. The effects also spill over to substitute crops through changes in relative profitability. These findings suggest that crop insurance policies should consider substitution relationships among crops to maintain production stability and mitigate price volatility. - COLLAPSE
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Plant & Forest
- Evaluating the relative importance of natural disaster prevention indicators by forest road stage
- Seong Man Kim, Ji-Young Son, Hyeongkeun Kweon, Ye Jun Choe, Joon-Woo Lee, Sung-Min Choi
- As climate change accelerates the frequency and scale of forest disasters, the role of forest roads as crucial infrastructure for forest management …
- As climate change accelerates the frequency and scale of forest disasters, the role of forest roads as crucial infrastructure for forest management and disaster response has become increasingly important. However, forest roads are inherently vulnerable to heavy rainfall, and existing research has largely focused on site-specific damage or post-disaster recovery rather than a comprehensive life-cycle approach. Furthermore, traditional multi-criteria decision-making methods often suffer from splitting bias when evaluating asymmetric hierarchical structures. Therefore, this study aimed to derive the relative importance and priorities of natural disaster prevention indicators across the four stages of a forest road’s life cycle (planning, design, construction, and maintenance) by applying a global weighting approach based on global normalization. The results revealed that in the planning and design stages, practitioners prioritized active engineering controls—such as route selection to avoid landslide-prone areas, structural reinforcement of fill slopes (e.g., retaining walls), and the optimization of drainage facilities—over passive environmental surveys. In the construction stage, ‘benching’ to induce mechanical interlocking between the original ground and fill slopes, alongside the installation of side ditches, emerged as the most critical factors to prevent sliding and erosion. During the maintenance stage, uncontrolled water (overflow and subsidence) flowing into fill slopes was evaluated as the greatest threat; however, the broad distribution of evaluation indicators highlighted the current limitations of fragmented and reactive management. Ultimately, establishing disaster-resilient forest roads requires a paradigm shift in design and construction standards, prioritizing the maximization of drainage capacity and the structural stabilization of fill slopes. This study provides practical guidelines for forest road policies and emphasizes the urgent need to develop a quantitative risk assessment model for proactive maintenance. - COLLAPSE
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Engineering
- Thermal-flow analysis and CFD model development for the hood of a hydrogen fuel-cell tractor
- Ju Hyeok Jung, Jong Dae Park, Hyeon Ho Jeon, Yu Shin Ha, Yong Joo Kim
- In this study, the thermal-flow characteristics inside the hood of a hydrogen fuel-cell tractor were analyzed, during a maximum-power test, using a …
- In this study, the thermal-flow characteristics inside the hood of a hydrogen fuel-cell tractor were analyzed, during a maximum-power test, using a power take-off (PTO) dynamometer. Temperature sensors were installed at multiple locations around the coolant cooler, fuel-cell cooler, and powerpack to characterize the under-hood thermal flow. The results showed that relatively high temperatures and large temperature variations occurred around the fuel-cell cooler outlet and the powerpack region, where relatively large temperature variations were observed. A thermal-flow simulation model was developed using Ansys Fluent and validated through comparison with measured data, showing no statistically significant difference between the measured and simulated temperatures. Based on the measured and simulated results, two modified hood designs an enlarged square vent and a square vent combined with a rear bulkhead were evaluated. The modified models reduced the internal hood temperature, stabilized airflow and pressure distribution, and mitigated heat accumulation around the powerpack. Specifically, the maximum powerpack temperature decreased from 58.94℃ in the baseline round-vent model to 56.85℃ in the enlarged square-vent model and 54.04℃ in the square vent + rear bulkhead model, corresponding to reductions of 2.09℃ (3.5%) and 4.90℃ (8.3%), respectively. Among the evaluated cases, the square vent + rear bulkhead configuration showed the best cooling performance. Therefore, the proposed design modifications can serve as an effective design strategy for improving cooling performance in hydrogen fuel-cell tractors. - COLLAPSE
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Food & Chemistry
- Environmental distribution and food-web transfer of DDT and fipronil sulfone in agricultural wetland ecosystems: A case study of oriental stork restoration habitats
- Hae-Suk Lee, Chi-Hwan Lim
- This study evaluated the environmental distribution and food-web transfer characteristics of p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) and fipronil sulfone in agricultural wetland ecosystems using a …
- This study evaluated the environmental distribution and food-web transfer characteristics of p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) and fipronil sulfone in agricultural wetland ecosystems using a restored oriental stork (Ciconia boyciana) population inhabiting both managed feeding and natural food-web environments in Yesan and Taean, Chungcheongnam-do, Republic of Korea. Samples were collected from soil, stream water, prey organisms, stork eggs, feathers, and regurgitated materials. The results showed that p,p′-DDE was not detected in environmental matrices but was detected in externally supplied prey organisms, including horse mackerel (Trachurus japonicus), as well as in stork eggs, feathers, and regurgitated materials. The mean concentrations of p,p′-DDE in stork eggs ranged from 0.023 to 0.065 mg/kg, and the biomagnification factor (BMF) ranged from 11.35 to 32.60. In contrast, fipronil sulfone was detected in soil and naturally collected prey organisms from the Taean region but was not detected in stork-related samples. In addition, fipronil sulfone concentrations differed significantly among sample groups (F = 3.98, p = 0.007). Comparison of the same restored stork population under managed feeding and natural food-web environments demonstrated distinct occurrence and food-web transfer characteristics between p,p′-DDE and fipronil sulfone. p,p′-DDE was detected primarily in biological samples and exhibited high BMF values, whereas fipronil sulfone was mainly detected in environmental matrices and lower trophic prey organisms, indicating limited transfer to higher trophic levels. These findings suggest that the environmental fate and trophic transfer of pesticide residues in agricultural wetland ecosystems differ according to their persistence and bioaccumulation characteristics. Furthermore, an integrated assessment incorporating environmental matrices, prey organisms, and upper trophic predators is essential for evaluating long-term ecological exposure in agricultural wetland ecosystems. - COLLAPSE
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Management & Economics
- Onion wholesale price forecasting: A comprehensive study of traditional time series and AI-based approaches
- Jaehong Park, Seungjee Hong
- Agricultural price forecasting studies increasingly favor machine learning, deep learning, and hybrid models over traditional statistical approaches, yet few studies test whether …
- Agricultural price forecasting studies increasingly favor machine learning, deep learning, and hybrid models over traditional statistical approaches, yet few studies test whether this added complexity is justified under realistic data constraints. This study compares seven forecasting methodologies for onion wholesale price using daily data from the Garak wholesale market (June 2023 - December 2025, 788 observations): traditional time series models (autoregressive integrated moving average [ARIMA], seasonal autoregressive integrated moving average [SARIMA]), machine learning (extreme gradient boosting [XGBoost]), deep learning (long short-term memory [LSTM], gated recurrent unit [GRU]), and hybrid models (ARIMA-LSTM, variational mode decomposition [VMD]-LSTM). Models were evaluated via leakage-free rolling one-day-ahead walk-forward forecasts using mean absolute error (MAE), root mean squared error (RMSE), mean absolute percentage error (MAPE), coefficient of determination (R2), and directional accuracy, with Diebold-Mariano tests, and further compared across forecast horizons (1, 7, 14, and 30 days) and seasons. Contrary to common expectations, the simplest models performed competitively: ARIMA (MAE 17.39 won/kg, R2 = 0.518) and GRU (MAE 17.67 won/kg, R2 = 0.564) achieved the best accuracy, SARIMA showed no significant improvement over ARIMA (p = 0.183), and VMD-LSTM was significantly outperformed by the simpler ARIMA-LSTM (p < 0.001). XGBoost’s one-day error exceeded ARIMA’s and SARIMA’s, and deteriorated most severely among all models as the horizon lengthened due to recursive error accumulation. These results align with evidence that machine learning needs large training samples to outperform simple statistical benchmarks, and that reported gains from VMD hybrids may partly reflect information leakage, indicating that complexity does not guarantee performance under limited data. The findings offer practical guidance for selecting forecasting models in data-constrained agricultural price settings. - COLLAPSE
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Animal
- Meat quality attributes of loin among different beef marbling scores within 1++ grade Hanwoo steers
- Woo Heo, Shil Jin, Seul-Ki-Chan Jeong, Hayeon Jeon, Soeun Kim, Seokhee Han, Hanwool Do, Samooel Jung
- This study was conducted to evaluate the meat quality characteristics of Hanwoo loin according to different beef marbling score (BMS; No. 7, …
- This study was conducted to evaluate the meat quality characteristics of Hanwoo loin according to different beef marbling score (BMS; No. 7, 8, and 9) levels within the 1++ quality grade. The BMS No. 9 group showed significantly higher crude fat content and lower moisture and crude protein contents than the BMS No. 7 and 8 groups (p < 0.05). Additionally, cooking loss and Warner-Bratzler shear force were significantly lower in the BMS No. 9 group than in the other groups (p < 0.05), whereas no significant differences in pH were observed among the BMS groups (p > 0.05). Spearman rank correlation analysis revealed that crude fat content was strongly negatively correlated with moisture (rs = -0.98) and crude protein contents (rs = -0.90), and moderately negatively correlated with cooking loss (rs = -0.46) and shear force (rs = -0.25) (p < 0.01). These findings demonstrate that the BMS No. 9 group exhibited distinct proximate composition and meat quality attributes compared with the BMS No. 7 and 8 groups, even within the same 1++ quality grade, suggesting that subdividing the 1++ grade is necessary to provide more precise quality information for highly marbled Hanwoo beef. - COLLAPSE
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Management & Economics
- Dynamic price transmission across egg distribution stages
- Yujin Seo, Tongjoo Suh
- Long-term price adjustments have primarily been examined using low-frequency data. By contrast, this study uses daily data from 2020 to 2025 to …
- Long-term price adjustments have primarily been examined using low-frequency data. By contrast, this study uses daily data from 2020 to 2025 to investigate the dynamic effects of exogenous shocks—specifically, movement restrictions due to avian influenza, heatwaves, and holidays—on price transmission across different stages of the distribution channel. A vector autoregression with exogenous variables model was employed for the analysis. The findings indicate weak short-run price transmission from the farm-level and wholesale stages to the retail stage. The observed pattern may reflect price rigidity in the retail market, which remains relatively insulated from price shocks at the farm and wholesale levels. This suggests that policy interventions may need to move beyond aggregate measures and be tailored to address potential inefficiencies within each market segment. - COLLAPSE
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Plant & Forest
- Diversity and phylogeny of ten unrecorded ectomycorrhizal basidiomycetes in Korea
- Sung-Eun Cho, Jae Young Park, Yong Ho Kim, Jin Sung Lee, Keum Chul Shin, Nam Kyu Kim
- During comprehensive fungal diversity surveys in South Korea, ten macrofungal species previously unrecorded were identified. These species belong to four families within …
- During comprehensive fungal diversity surveys in South Korea, ten macrofungal species previously unrecorded were identified. These species belong to four families within the phylum Basidiomycota: Cortinariaceae (Cortinarius acutus), Russulaceae (Russula burlinghamiae, R. callainomarginis, R. subatropurpurea, R. zhuzuijun), Boletaceae (Tylopilus pseudoballoui, Pulveroboletus subrufus, Porphyrellus orientifumosipes, Xerocomellus inflatus), and Sclerodermataceae (Scleroderma venenatum). Species identification was confirmed through a combination of macro- and microscopic morphological examinations and molecular phylogenetic analyses based on the internal transcribed spacer (ITS) and large subunit (LSU) regions of the ribosomal RNA gene. Detailed morphological descriptions, photographs, and phylogenetic trees for these newly recorded species are provided. This report significantly contributes to the inventory of indigenous fungal resources and highlights the hidden mycological diversity within Korean forest ecosystems. - COLLAPSE
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Animal
- Effects of sample size and measurement interval on the goodness of fit of growth curve models in Hanwoo steers
- Ji Min Kang, Shil Jin, Sung-Sik Kang, Jun Kyu Son, Hanwool Do, Yonghwan Kim, Jeong Il Won
- This study was conducted to evaluate the effects of sample size and measurement interval on the goodness of fit of growth curve …
- This study was conducted to evaluate the effects of sample size and measurement interval on the goodness of fit of growth curve models in Hanwoo steers using simulated body weight data. A simulated population of 2,000 animals was generated from the 2024 monthly reference body weights for Hanwoo steers, with random values assigned within ±15% of the reference weight at each month of age. From this population, 10, 30, 50, and 100 animals were randomly sampled under three measurement interval schemes: monthly, every 2 months, and every 3 months. Each sampling condition was repeated 10 times. Growth data were fitted using the Gompertz, von Bertalanffy, and Logistic models, and model performance was evaluated using the coefficient of determination (R2) and root mean square error (RMSE). The results showed that the von Bertalanffy model consistently had the highest R2 and the lowest RMSE across all sample sizes and measurement intervals, followed by the Gompertz model, whereas the Logistic model showed the poorest fit. As sample size increased, the variability of the mean growth curve decreased and model fit improved; however, the improvement became limited beyond 50 animals. In contrast, differences in model fit among measurement intervals were relatively small, indicating that growth patterns could still be described reasonably well using measurements taken every 2 or 3 months. These findings suggest that the von Bertalanffy model is the most suitable for describing average growth patterns in Hanwoo steers and that practical growth curve analysis may be possible with moderate sample sizes and less frequent measurements. - COLLAPSE
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Plant & Forest
- Comparative seed traits, germination, and dormancy status of 18 native plant species in Korea
- Sung Min Han, Kyong-Hee Nam
- Species-specific information on seed traits is essential for the conservation, propagation, and restoration of plant genetic resources. In this study, we characterized …
- Species-specific information on seed traits is essential for the conservation, propagation, and restoration of plant genetic resources. In this study, we characterized the physical and morphological traits, germination performance, and estimated dormancy status of seeds from 18 plant species occurring in Korea, including two nationally designated Class II endangered wildlife species, Iris laevigata and Lychnis wilfordii. The species were selected based on the availability of mature seed lots obtained through field collection and ex situ conservation activities. Seed lots were harvested in 2020 or 2023 and stored at 4℃ in dry, sealed containers until analysis. Seed size, weight, and surface structure differed markedly among species. Final germination percentages also varied substantially among species, with the highest value of 83.0% observed in Geum aleppicum. Viable but non-germinated seeds were detected in several species, including multiple Iris species. Discrepancies between the present germination results and data from the Korea National Arboretum may reflect differences in seed source, maternal environment, initial seed quality, collection year, and germination-test conditions; because these factors were not controlled across datasets, the cause of the discrepancies could not be determined. Our results provide baseline information on the available seed lots and demonstrate the need for species-specific germination protocols and standardized storage experiments. Furthermore, an integrated seed-trait database incorporating morphological, physiological, ecological, and seed-lot information would improve the reliability of future conservation and propagation programs. - COLLAPSE
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Management & Economics
- Effects of local food direct market openings on regional farm structure: Staggered difference-in-differences evidence from 56 si and gun in Korea
- Chaebeen Yoon, Juyoung Yoo
- Local food direct markets are Korea’s principal policy instrument for direct-to-consumer agricultural marketing, yet whether they reshape regional farm structure remains untested …
- Local food direct markets are Korea’s principal policy instrument for direct-to-consumer agricultural marketing, yet whether they reshape regional farm structure remains untested because existing evidence relies on surveys of participating farms, which are subject to self-selection. We examine whether direct market openings change crop composition and farm management structure at the si and gun level. Using a staggered difference-in-differences design and an annual panel of 56 si and gun in three Korean provinces from 2010 to 2023, we find no significant effects on crop composition: five diversity indices including the Herfindahl index, the share of vegetable and fruit farms, and paddy reliance measures show no significant change, although the confidence intervals do not rule out modest effects. The full-time farm share rises by 4.2 percentage points and the number of full-time farm households increases by approximately 13.5%, both significant at the 1% level, while total farm households show no significant change—a pattern consistent with transitions of existing part-time farms into full-time farming. These results suggest that the effects of direct market openings appear in farm households’ labor allocation rather than in crop conversion, which entails substantial fixed costs. Our findings caution against evaluating direct market programs solely by short-term changes in regional crop composition and suggest that management-type indicators merit consideration as complementary performance measures. - COLLAPSE
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Management & Economics
- Analysis on the economic effect of the egg grading system
- Sang Gon Jeon, Gwangsik Oh, Sounghun Kim
- In Korea, eggs serve as a critical source of daily protein. However, the egg industry has long faced market inefficiencies due to …
- In Korea, eggs serve as a critical source of daily protein. However, the egg industry has long faced market inefficiencies due to a lack of quality evaluation standards and reliance on post-settlement price discovery mechanisms. To address these issues, the government implemented the egg grading system. This study quantitatively evaluates the economic welfare impacts of introducing the egg grading system using an equilibrium displacement model (EDM), a comparative static analysis framework. Annual time-series data from 2005 to 2023 were utilized to estimate the price elasticities of egg demand and supply via regression analysis, yielding an inelastic price elasticity of demand (𝜂 = -0.222) and price elasticity of supply (𝜀 = 0.210). Market shifts were modeled by incorporating an estimated 1.74% increase in consumer willingness-to-pay resulting from enhanced quality information trust, alongside a 0.20% increase in distribution costs incurred by grading operations. The empirical results reveal that the introduction of the egg grading system generates a total annual social welfare gain of approximately 79.7 billion KRW, consisting of a 44.9 billion KRW increase in consumer surplus and a 34.8 billion KRW increase in producer surplus. These findings demonstrate that despite modest cost increases, the economic benefits stemming from improved consumer trust and market efficiency significantly outweigh the implementation costs, providing robust empirical justification for the mandatory expansion of the egg grading system. - COLLAPSE
Journal Informaiton
Korean Journal of Agricultural Science
Korean Journal of Agricultural Science
Institute of Agricultural Science, Chungnam National University
충남대학교 농업과학연구소
99, Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
Tel: +82-42-821-6709 / Fax: +82-42-821-8890 / E-mail: cnuagro@cnu.ac.kr Copyright© Institute of Agricultural Science, Chungnam National University. Powered by APUB
Tel: +82-42-821-6709 / Fax: +82-42-821-8890 / E-mail: cnuagro@cnu.ac.kr Copyright© Institute of Agricultural Science, Chungnam National University. Powered by APUB