• Korean Journal of Environmental Agriculture
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• v.25 no.3
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• pp.268-275
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• 2006

ALA (5-aminolevulinic acid) has been proposed as a tetrapyrrole-dependent photodynamic herbicide by the action of the protoporphyrinogen IX oxidase (Protox IX). A study was conducted to determine photodynamic herbicidal effect of ALA on seedling growth of rice (Oryza sativa L.) and barnyard grass (Echinochloa crus-galli Beauv. var. oryzicola Ohwi) under dry and wet conditions. ALA effect on early plant growth of rice and barnyardgrass was greatly concentration dependant, suggesting that it promotes plant growth at very low concentration and inhibits at high concentration. No significant difference in herbicidal activity of biologically and synthetically produced ALAs on plant lengths of test plants was observed ALA exhibited significant photodynamic activity regardless of PSDIP and its duration. Significant shoot growth inhibition by ALA soaking treatment exhibited apparently, indicating that ALA absorbed through root system was translocated into shoot part of plants. ALA reduced plant heights of rice and barnyardgrass seedlings by 6% and 27%, respectively, showing more tolerant to ALA in rice under wet condition. Leaf thickness was reduced markedly by ALA with increasing of ALA concentration, due to mainly membrane destruction and severe loss of turgidity in mesophyll cells, although the epidermal was little affected. It was observed that photodynamic herbicidal activity of ALA applied by pre-and post-emergence application exhibited differently on plant species, and that the activity of ALA against susceptible plants was highly correlated with growing condition.

• Korean Journal of Organic Agriculture
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• v.27 no.1
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• pp.17-32
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• 2019

The objective of this study is to investigate the effect of pesticide-related accident on prices and sales of eggs and the perception of food safety accidents among consumers. For this, we analyzed the impact of the pesticide incident on consumers' purchases by separating large discount stores and eco-friendly specialty stores with econometrics methods. In addition, the value changes for each egg certification were analyzed after the accident. Perception of food safety accidents was conducted through a survey to investigate the awareness of the pesticide-related accidents, changes in purchases, and the causes of the pesticide accidents. Furthermore, the risk analysis was conducted. This results show the importance of trust and communication in food safety accidents between distributors, consumers and concerned authorities. Also, after the accident, consumers' interest and premium exist in the breeding process such as animal welfare, not only in the final product. Therefore in order to actively respond to food safety accidents such as pesticides-related accident, response and improvement are necessary considering various aspects such as risk assessment, risk management, and risk communication.

• Korean Journal of Organic Agriculture
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• v.30 no.4
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• pp.517-528
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• 2022

This study analyzed the factors influencing the demand for processed products of ugly agricultural products targeting 300 consumers. First, the awareness of the problem of the disposal of ugly agricultural products was very high at 72%. In other words, it can be seen that consumers are highly interested in environmental issues caused by the disposal of ugly agricultural products. Second, the experience of purchasing ugly agricultural products is high at 73%, which is proof that consumers are highly aware of and likely to purchase ugly agricultural products. Third, 77.6% of the respondents said they were willing to purchase processed ugly agricultural products. In other words, it was found that the intention to consume ugly agricultural products was sufficient. Finally, the conjoint analysis was applied to analyze the attribute value of ugly agricultural products. As a result of calculating the total utility of the optimal properties and optimal properties of the ugly fruit fermented, the total utility of the optimal properties was 0.778, the price was 0.481, the eco-friendly certification was 0.004, and the fruit syrup ratio was 0.294.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.657-666
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• 2022

Nitrogen (N) is a vital element in growing crops and is essential for improving the yield and quality of crops. Thus, N fertilizer is the most widely used fertilizer and the primary N input source in soil-crop systems. Inorganic fertilizers such as urea are known to improve crop productivity and increase soil fertility. However, application with excessive amounts can interfere with crop growth and accelerate soil acidification. For these reasons, the use of organic fertilizers, which mainly contain organic nitrogen, has gradually increased worldwide. Therefore, this study evaluated the effects of N fertilizer on the growth of Chinese cabbage including its functional compounds glucosinolates (GSLs). For the cultivation of Chinse cabbage, inorganic fertilizer was used for urea, and organic fertilizers were divided into conventional and biochar-based fertilizers. The growth parameters of Chinese cabbage treated by organic fertilizers was better than those of the inorganic fertilizers. Additionally, it was found that their co-application was more efficient. However, their GSL contents were lower with the application of the organic fertilizers. The characteristics of the experimental soil also changed according to the type, amounts and co-application of fertilizers. Therefore, this study presents the basis for an eco-friendly method that can increase the functionality and productivity of Chinese cabbage compared to conventional cultivations.

• Research in Plant Disease
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• v.22 no.2
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• pp.72-80
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• 2016

Gummy stem blight, caused by the fungus Didymella bryoniae, is major disease of watermelons worldwide. The objective of the present study was to establish an efficient screening system to identify watermelon resistant to D. bryoniae. An GSB3 isolate was prepared from a watermelon plant showing typical symptoms of gummy stem blight in Haman-gun and identified as D. bryoniae based on molecular analysis of internal transcribed spacer sequence. A simple mass-production technique of inoculum was developed based on spore production of D. bryoniae GSB3 under several incubation conditions and their virulence on watermelon plants. Resistance degrees of 22 commercial watermelon cultivars to the GSB3 isolate were evaluated. Among them, four watermelon cultivars showing different degree of resistance response were selected for further study. Development of disease on the cultivars according to various conditions including inoculum concentrations, incubation periods in dew chamber, and incubation temperatures was investigated. From the results, we suggest an efficient screening method for resistant watermelon cultivars to gummy stem blight. Seeds of watermelon cultivar are sown and grown in a greenhouse until plant stage of 2-fully expanded leaves. Seedlings are inoculated with D. bryoniae by spraying spore suspension of the fungus at a concentration of $5.0{\times}10^5spores/ml$. The infected plants are incubated in humidity chamber at $25^{\circ}C$ for 48 hours and then transferred to a growth chamber at $25^{\circ}C$ and 80% relative humidity with 12-hour light a day. Three to four days after inoculation, disease severity of the plant are measured using percentage of infected leaf area.

• Research in Plant Disease
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• v.21 no.4
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• pp.290-296
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• 2015

This study was conducted to establish an efficient screening system for resistant tomato to bacterial wilt caused by Ralstonia solanacearum. Under several conditions such as inoculation methods, growth stages of tomato seedlings, inoculum concentrations, and incubating temperatures after inoculation, development of bacterial wilt on nine resistant or susceptible cultivars of tomato was investigated. To inoculate by drenching the non-cut roots with the bacterial suspension was better to distinguish resistance and susceptibility of tomato cultivars than by drenching the cut roots using scalpel. And 'Hawaii7996' a resistant tomato to R. solanacearum showed high resistance at all the tested conditions including growth stages (3-, 6-, 8-, 10-leaf stages), inoculum concentrations ($OD_{600}=0.1-0.4$) and incubation temperatures (25, 30, $35^{\circ}C$). On the other hands, susceptible cultivars represented disease index of 3.7 and 3.9 at 6- and 8-leaf stages, respectively. At 3- and 10-leaf stages, the cultivars demonstrated lower disease severity of 2.1 and 0.5, respectively, than at 6- and 8-leaf stages. When the inoculated seedlings were incubated in growth chambers of 25, 30 and $35^{\circ}C$, disease severity of susceptible cultivars was significantly greater at 30 and $35^{\circ}C$ than at $25^{\circ}C$. In addition, the level of resistance of the tomato cultivars was not significantly affected by inoculum concentrations of $OD_{600}=0.1-0.4$. On the basis of the results, we suggest an efficient screening method to measure resistance level of tomato cultivars to bacterial wilt. The eight-leaf stage seedlings transplanted 7 days before inoculation, are inoculated with R. solanacearum by drenching the non-cut roots with a bacterial suspensions ($OD_{600}=0.4$) to give inoculum volume of 50 ml/soil l. The inoculated plants are incubated in a growth room at $30^{\circ}C$ for 12-13 days with 12-hour light a day.

• Research in Plant Disease
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• v.21 no.3
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• pp.201-207
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• 2015

This study was conducted to establish a simple mass-screening method for resistant melon to Fusarium wilt caused by Fusarium oxysporum f. sp. melonis (FOM). Root-dipping inoculation method has been used to investigate resistance of melon plants to Fusarium wilt. However, the inoculation method requires a lot of labor and time because of complicate procedure. To develop a simple screening method on melon Fusarium wilt, occurrence of Fusarium wilt on susceptible and resistant cultivars of melon according to inoculation method including root-dipping, soil-drenching, tip, and scalpel methods was investigated. Scalpel and tip methods showed more clear resistant and susceptible responses in the melon cultivars than root-dipping inoculation method, but tip method represented slightly variable disease severity. In contrast, in the case of soil-drenching inoculation method, disease severity of the susceptible cultivars was very low. Thus we selected scalpel method as inoculation method of a simple screening method for melon Fusarium wilt. By using the scalpel inoculation method, resistance degrees of the cultivars according to incubation temperature after inoculation (25 and $30^{\circ}C$) and inoculum concentration ($1{\times}10^6$ and $1{\times}10^7conidia/ml$) were measured. The resistance or susceptibility of the cultivars was hardly affected by all the tested conditions. To look into the effectiveness of scalpel inoculation methods, resistance of 22 commercial melon cultivars to FOM was compare with root-dipping inoculation method. When the melon cultivars were inoculated by scalpel method, resistance responses of all the tested cultivars were clearly distinguished as by root-dipping method. Taken together, we suggest that an efficient simple mass-screening method for resistant melon plant to Fusarium wilt is to sow the seeds of melon in a pot (70 ml of soil) and to grow the seedlings in a greenhouse ($25{\pm}5^{\circ}C$) for 7 days, to cut the root of seedlings with a scalpel and then pour a 10 ml-aliquot of the spore suspension of $1{\times}10^6conidia/ml$ on soil. The infected plants were cultivated in a growth room at 25 to $30^{\circ}C$ for about 3 weeks with 12-hr light a day.

• Journal of the Korean Wood Science and Technology
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• v.52 no.3
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• pp.221-233
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• 2024

Lignin, a prominent constituent of woody biomass, is abundant in nature, cost-effective, and contains various functional groups, including hydroxyl groups. Owing to these characteristics, they have the potential to replace petroleum-based polyols in the polyurethane industry, offering a solution to environmental problems linked to resource depletion and CO₂ emissions. However, the structural complexity and low reactivity of lignin present challenges for its direct application in polyurethane materials. In this study, Kraft lignin (KL), a representative technical lignin, was fractionated with ethanol, an eco-friendly solvent, and mixed with conventional polyols in varying proportions to produce polyurethane films. The results of ethanol fractionation showed that the polydispersity of ethanol-soluble lignin (ESL) decreased from 3.71 to 2.72 and the hydroxyl content of ESL increased from 4.20 mmol/g to 5.49 mmol/g. Consequently, the polyurethane prepared by adding ESL was superior to the KL-based film, exhibiting improved miscibility with petrochemical-based polyols and reactivity with isocyanate groups. Consequently, the films using ESL as the polyol exhibited reduced shrinkage and a more uniform structure. Optical microscope and scanning electron microscope observations confirmed that lignin aggregation was lower in polyurethane with ESL than in that with KL. When the hydrophobicity of the samples was measured using the water contact angle, the addition of ESL resulted in higher hydrophobicity. In addition, as the amount of ESL added increased, an increase of 7.4% in the residual char was observed, and a 4.04% increase in Tmax the thermal stability of the produced polyurethane was effectively improved.

• Food Science and Industry
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• v.53 no.1
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• pp.33-42
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• 2020

In accordance with the recent trend of environmentally friendly agricultural policy, product registration of agricultural chitosan among the organic materials has been displayed in various forms such as soil improving agent, crop growth, and pest control. Chitin production industry is expected to bring competitiveness by producing low-quality and low-cost chitin for agriculture, rather than high-quality and high-cost for food, medical products. Since there are various soil microorganisms that can decompose chitin and chitosan in farm soil where crops are produced, it can be applied usefully to agricultural sites suitably for crop growth and pest control using chitin and chitosan as substrates. The purpose of this study is to compare and analyze the registration status of organic materials companies using chitin and chitosan raw materials in the organic materials information system of the NAQS, and to provide an opportunity to further expand the agricultural use of domestic chitin and chitosan.

• Korean Journal of Organic Agriculture
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• v.23 no.2
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• pp.311-322
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• 2015

The study was conducted on growth and yield of potatoes in a wick hydroponic culture as affected by concentration of aqueous extracts in order to develop natural agricultural resources using Persicaria longiseta. Each 500 ml of distilled water (control) and P. blumei extracts (25%, 50%, 75%, and 100%) was applied to potato plants at 5 d intervals from 1 d after potato transplanting. The potatoes with P. blumei extract emerged 1 d earlier and had 0.3 to 0.4 more stem numbers per plant compared with those of control plot. The plant height was higher in plots with P. blumei extract than in control in early stage of potatoes (50 d), but there was no significant difference observed after mid-stage of potatoes (70 and 90 d). The stem diameter and fresh weight of potatoes estimated a higher values in plots with P. blumei extract than in control plots, although there was no statistical difference. The 100% P. blumei extract increased by up to $13.8kg/m^2$ of potato yield. The numbers of tubers in classes of < 5 g and 5 to 30 g per plant did not show a specific trend among experimental treatments while it in class of > 30 g was much higher in plots with P. blumei extract than in control plot. Accordingly, the P. blumei extract had a positive effect on the growth and yield of potatoes, could be applied as of eco-friendly fertilizers