• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.253-264
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• 2022

In this study, we investigated the occurrence of viral diseases in the early growth stage of soybean to establish management practices. We collected 83 soybean samples showing abnormal symptoms, approximately 3-4 weeks after seeding in the breeding field of the National Institute of Crop Science. Viruses were detected in the collected samples using reverse transcription polymerase chain reaction (RT-PCR) and metatranscriptome analysis of all those samples. The incidence of viral diseases in the field was less than 1% overall and up to 50% in certain cultivars and lines. RT-PCR and metatranscriptome analysis detected Soybean yellow mottle mosaic virus (SYMMV), Soybean mosaic virus (SMV), Soybean yellow common mosaic virus, Peanut stunt virus, and soybean geminivirus A (SGVA). Among these detected viruses, SYMMV and SMV were identified as major viruses causing infection in the early growth stage of soybean, with detection rates of 53.7% and 42.6%, respectively. Soybeans infected with SYMMV showed typical mosaic symptoms, whereas those infected with SMV showed a variety of symptoms such as mosaic, mottle, stunt, and chlorotic spots. Transmission characteristics of these viruses are variable, such that SMV is primarily transmitted by seeds, whereas SYMMV could be transmitted by insects, soil, and seeds. In this study, SGVA was detected in the early growth stage of soybean, and research on the current status and its effects on soybean after the early growth stage should be conducted.

• Proceedings of the Mineralogical Society of Korea Conference
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• 1996.10a
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• pp.7-24
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• 1996

'90년대 전반기 중 세계 경제 상황은 정치, 경제 및 환경의 급격한 변화에 따른 불황으로 유황시장에도 심대한 영향을 미치게 되었다. 이와 같은 경기의 후퇴는 다수의 생산자로 하여금 전반적인 시장 상황을 바꿀 수 있는 전략 변경 및 새로운 시장 개발을 촉진시키게 하였다. 최근에 전개되고 있는 극단적인 정치$\cdot$경제적인 변화는 재래시장과 무역균형을 변경시키게 되었다. 개선되는 세계경제에 따른 광범위한 구조조정과 지난 2년간 진행되어온 전반적으로 농업에 유리한 조건에 힘입어 1995년 유황공업은 회복이 시작되어 54.63백만 톤이 생산되었다 국제 유황 무역은 수요와 공급 면에서는 균형을 못 찾고 있다. 1995년 유황생산 중 무역량은 $45\%$에 이르렀다. 유황생산에 영향하는 요소가 변함에 따라 무역의 형태가 변하게 되고 세계 유황 수급 균형에 영향을 주게 되었다. 지난 2년간 있었던 유황생산 회복은 다음 십년간 지속될 것으로 예측된다. 대부분 수요의 증가는 자연가스의 생산을 지배하는 요소에 따라 결정 될 것이다 1986년 이래 유가가 떨어진 후 세계 에너지 수요는 연간 $2.3\%$ 증가하였다. 석유와 가스는 미래 에너지 수요의 증가로 $70\%$이상을 공급하게 될 것이다. 동아시아에서 회수 유황은 원유의 정제로부터 유래된 것으로 가장 신장이 큰 공급원으로 2005년까지 주요유황생산 부분이 될 것이다. 동아시아에서 주요 회수 유황생산국은 일본으로 전체의 $66\%$를 차지한다. 석유 정제로부터 회수 유황생산량은 동아시아에서 증가하고 있다. 유황회수 시설 투자는 일본을 위시하여 한국, 싱가폴 및 태국에서 이루어지고 있으며 이는 점차 증대되는 환경규제에 기인된다. 동아시아 공업국가 예컨대 일본과 한국에서의 유황소비는 인산생산 저조로 정체해 있으나 지난 10년간 여타의 아시아 국가에서의 유황소비는 꾸준히 증가되었다. 이 같은 증가는 앞으로 10년간 계속 될 것으로 추정된다. 이는 유황비료 소비가 4.81백만 톤에서 6.6백만 톤으로 증가될 것으로 예상되고 이는 주로 중국이 내수 인산생산을 증가시키려는 데 기인된다. 더욱이 다가올 10년은 다수의 아시아 국가의 급속한 경제 발전으로 비료 이외의 유황의 소비가 꾸준히 증가 될 것이다. 동아시아는 10.29백만 톤을 생산하고 10.99백만 톤을 소비하여 1995년에는 70만 톤의 유황이 부족하였다. 이와 같은 영향이 계속된다면 동아시아 유황부족은 2005년에는 1.05백만 톤으로 증가될 것으로 예상된다. 그러나 중국에서 황화철에서부터 공급되는 유황함량이 많아 이 지역에서의 원소유황의 진정한 균형에 대해서는 정확하게 평가되지 못한다. 1995년 동아시아에서는 1.3백만 톤의 원소유황을 일본, 캐나다, 미국에서 수입했다. 이들 국가는 앞으로도 이 지역의 주요 공급자가 될 것이다. 황산의 많은 양은 일본에서 이 지역으로 수출되는데 그 양은 1995년 10만톤 이상에 이른다. 더욱이 경제?환경적 이점 때문에 중국이 황화물에서 회수하는 유황대신 원소 유황의 수입을 지속적으로 증가시키고 있어 지역내의 유황 부족이 증가 될 것이다. 이 같은 상황진전으로 앞으로 10년 이내에 2.5백만 톤의 추가시장이 있게 될 것이다. 이 기간내 한국으로서 현재 326,000톤의 부족에서 2005년에는 309,000톤의 과잉으로 유황균형이 변할 수 있는 주요계기가 될 것이다 이 같은 과잉은 회수 유황생산이 1995년 333,000톤에서 2005년 870,000톤으로 $161\%$가 증가될 것으로 예상된다. 동기간 내에 기타 유황생산은 280,000톤에서 320,000톤으로 $14\%$ 증가되는 것으로 추정된다. 그리하여 2005년 한국에서 유황 공급은 1.19백만 톤이고 수요는 881,000톤으로 추정 된다. 미래 한국에서 유황의 또 다른 잠재시장은 식물양분으로서 이다. 인산비료 생산은 유황산업의 골격으로 1995년 세계적으로 인산비료는 유황소비의 53%인 53.60백만 톤을 점유하였다. 작물의 유황결핍 현상은 세계도처에서 나타나고 있어 식물양분으로서 유황시장은 20년전의 시장과 같이 현황을 띠는 시장으로 유황공업이 때를 만나게 될 것이다. 공업국에서 유황의 대기로의 방출억제로 자연 공급량이 감소되고 개발도상국에서 증산으로 유황의 탈취가 증가됨에 따라 유황 부족은 점차 중요한 문제로 확산되고 있다. 세계적으로 $1993\~1994$년간 7.52백만 톤으로 추정되는 유황 부족이 농산물의 수량과 질을 하락시키는 결과를 가져오게 하였다: 이와 같은 현상으로 유황비료의 수요가 증대되었고 산업계는 수요증대에 대응할 기술개발에 노력하게 되었다. 현재의 식량생산과 비료 소비추세가 지속된다면 아시아에서 2000년까지 매년 4.5백만 톤의 유황부족이 있게 될 것이다 이와 같은 유황비료의 부족은 적절한 대책을 취하지 않는 한 2010년에는 6.5백만 톤으로 증가 될 것이다. 동아시아는 경제발전으로 유황비료 장기 잠재시장이 기대되고 새로운 시장으로 $50\%$이상을 점유하게 될 것이다. 서구와 북미에서 유황비료 산업은 이윤 있는 잠재시장으로 인정되고 상업적으로 앞서 있는 시장이다. 점증하는 수요에 대한 대처와 유황비료의 성공은 시장에서 가격에 좌우된다. 실제로 북미와 서구에서 현재의 소매가격은 유황 톤당 $266\~466\$$의 범위에 있다. 인도에서는 비료로서 유황시장은 덜 발달된 단계로서 대표가격은 $120\$$이다. 이 가격 범위로 보아 2010년에 동아시아 시장의 잠재 유황비료 시장은 3.4백만 톤에 이르고 비료공업에서 추가로 얻는 이윤은 408백만 내지 1조5천억$\$$이 될 것이다. 이와 같은 시장이 발전 될 수 있는 것은 계속된 제품개발과 비료산업 시장개척에 달려있다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.4
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• pp.243-248
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• 2022

This study was conducted to evaluate the effect of feeding the whole crop rice silage (WCRS) which partially replaces the imported grass hay crop on the milking performance of Holstein and profitability. Two experimental diets were used according to the traditional practice of dairy farms. The control diet (C) was composed of 13kg/day of mixed hay, 6.8kg/day concentrate, and orchardgrass/bermudagrass hay (1.8kg/day). The treatment diet (T) was composed of 9.6kg/day of mixed hay, 6.8kg/day of concentrate and 2.2kg/day of WCRS. The CP content of the WCRS (4.6%) was lower than orchardgrass (11.3%) and bermudagrass hay (8.4%) due to the harvest being 30days later than the optimum harvest date of rice. The lower intake was observed in T during the entire experiment period which seems to be related to the higher proportion of fiber in rice (p<0.05). No significant difference was found in milk production between C (26.9kg) and T (26.3kg) during the entire experiment period (p>0.05). Also, no difference in milk fat, milk protein, total solids, and milk composition was observed between the two diets. Higher income per head was resulted in T (21,141won) compared to C (21,915 won). These results indicate that the partial replacement of the grass hay by the WCRS can bring the profit to the dairy farm due to the no difference between the control diet and the treatment diet.

• Journal of Practical Agriculture & Fisheries Research
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• v.10 no.1
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• pp.43-58
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• 2008

This research was conducted to determine the alternative tool of chemical spray for rice cultivation using the unmanned helicopter(Yamaha, R-Max Type 2G-remote controlled system) at farmer's field in Korea. The unmanned helicopter tested was introduced form Japan. In Korea the application of chemicals by machine sprayer for pest management in rice cultivation has been ordinarily used at the farmer's level. However, it involved a relatively high cost and laborious for the small scale of cultivation per farm household. Farm population has been highly decreased to 7.5% in 2002 and the population is expected to rapidly reduce by 3.5% in 2012. In Japan, pest control depending on unmanned helicopter has been increased by leaps and bounds. This was due in part to the materialization of the low-cost production technology under agricultural policy and demand environmentally friendly farm products. The practicability of the unmanned helicopter in terms of super efficiency and effectiveness has been proven, and the farmers have understood that the unmanned helicopter is indispensable in the future farming system that they visualized. Also, the unmanned helicopter has been applied to rice, wheat, soybean, vegetables, fruit trees, pine trees for spraying chemicals and/or fertilizers in Japan Effect of disease control by unmanned helicopter was partially approved against rice blast and sheath blight. However, the result was not satisfactory due to the weather conditions and cultural practices. The spray density was also determined in this experiment at 0, 15, 30, and 60cm height from the paddy soil surface and there was 968 spots at 0cm, 1,560 spots at 15cm, 1,923 spots at 30cm, and 2,999 spots at 60cm height. However, no significant difference was found among the treatments. At the same time, there was no phytotoxicity observed under the chemical stray using this unmanned helicopter, nor the rice plant itself was damaged by the wind during the operation.

• Journal of Practical Agriculture & Fisheries Research
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• v.4 no.1
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• pp.110-118
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• 2002

This study was conducted to investigate the physiology of optimal reproductive age in Hanwoo for protection to decrease of reproductivity and improvement of production of offspring. Thirty two cows were devided into 4 groups of treatments : T1(12 months of age and 0.5kg daily gain), T2(12 months of age and 0.8kg daily gain), T3(15 months of age and 0.5kg daily gain) and T4(18 months of age and 0.5kg daily gain). The days of the first heat of treated cows were 263.3±6.4 days and average weight was 181.1±11.3kg. The conception rates of first insemination were 25%(T1) and 75%(T4), and the number of insemination of T3 and T4(both 1.5) was lower than those of T1 and T2(2.3 and 2.4), respectively. With regard to estrus return after the first parturition, T1, T2, T3 and T4 showed 66.2,76.7, 62.4 and 68.5 days, respectively, indicating the average days of estrus return was 65.7. Plasma progesterone(P4) concentration was nearly the same during the observation periods of treated cows and P4 began to be detected after 12months. Only 5(15.6%) out of 32cows showed normal estrus cycle and ovulation before 12 months. During the peri-parturition period, P4 concentration was rapidly decreased and there was no detection of P4 from parturition to 40 days after milking. P4 would be released again on 45 day after parturition. The results imply that the optimal reproductive age of Hanwoo heifers would be around at the 14 months of age, 110cm height and 265kg weight.

• Journal of Practical Agriculture & Fisheries Research
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• v.11 no.1
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• pp.79-94
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• 2009

The research project was conducted to develop a paper bagging machine for grape. This technology was aimed to highly reduce a labor for paper bagging in grape and bakery. In agriculture labor and farm population has rapidly decreased since 1980 in Korea so there was so limit in labor. In particular there is highly population in women and old age at rural area and thus labor cost is so high. Therefore a labor saving technology in agricultural sector might be needed to be replaced these old age with mechanical and labor saving tool in agriculture. The following was summarized of the research results for development of a paper bagging machine for grape. 1. Development of a new paper bagging machine for grape - This machine was designed by CATIA VI2/AUTO CAD2000 programme. - A paper bagging machine was mechanically binded a paper bag of grape which should be light and small size. This machine would be designed for women and old age with convenience during bagging work at the field site. - This machine was manufactured with total weight of less than 350g. - An overage bagging operation was more than 99% at the actual field process. - A paper bagging machine was designed with cartridge type which would be easily operated between rows and grape branches under field condition. - The type of cartridge pin was designed as a C-ring type with the length of 500mm which was good for bagging both grape and bakery. - In particular this machine was developed to easily operated among vines of the grape trees. 2. Field trials of a paper bagging machine in grape - There was high in grape quality as compared to the untreated control at the application of paper bagging machine. - The efficiency of paper bagging machine was 102% which was alternative tool for the conventional. - The roll pin of paper bagging machine was good with 5.3cm in terms of bagging precision. - There was no in grape quality between the paper bagging machine and the conventional method. - Disease infection and grape break was not in difference both treatments.

• Research in Plant Disease
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• v.28 no.4
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• pp.237-244
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• 2022

Chrysanthemum plants are one of the most economically important plants in South Korea. Both virus and viroid can cause diseases and economic damage to the plants. In this study, we investigated the detection of seven viruses and two viroids in 350 chrysanthemum plants cultivated in Yesan-gun, Chungcheongnam-do. Two viruses, chrysanthemum virus B (CVB) and tomato aspermy virus (TAV), and two viroids, chrysanthemum chlorotic mottle viroid (CChMVd) and chrysanthemum stunt viroid (CSVd), were detected in this study. The two viruses were detected in six samples and one sample, respectively. The two viroids were detected in 97 samples and 21 samples, respectively. The nucleotide sequences of the CVB-CN-Y, TAV-CN-Y, CChMVd-CN-Y, and CSVd-CN-Y obtained in this study showed 83.7-86.9%, 99.2-100.0%, 94.4-99.5%, and 95.7-99.7% identity, respectively, compared to their other strains/isolates. The CVB-CN-Y and TAV-CN-Y showed the greatest nucleotide sequence homology to CVB-GS1 and three TAV isolates (TAV-V, TAV-P, and TAV-ChJ), respectively. The CChMVd-CN-Y and CSVd-CN-Y showed the greatest nucleotide sequence homology to CChMVd-Horst and four CSVd isolates (Au1.1, K4pop, Sagae, and Tochigi), respectively. This study is the report on the infection rate of viruses and viroids in chrysanthemum plants cultivated in Yesan-gun in 2021.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.165-171
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• 2023

Potato dry rot is one of the potato storage diseases caused by Fusarium species and is a representative pathological disorder that induced post-harvest loss during storage. Chlorpropham treatment for sprouting inhibition is mainly used for room temperature storage of potatoes for processing. In this study, the inhibitory effect of chlorpropham on Fusarium-induced dry rot of potato 'Dano'. To investigate the mycelial growth rate of the dry rot fungus (Fusarium solani Appel & Wollenw), mycelial growth was investigated in a chlorpropham (5.0, 50.4, 503.8, and 5,038 ppm) and prochloraz (0.1, 1.0, 10.0, and 100.0 ppm) medium containing F. oxysporum mycelia. Mycelia were more inhibited as the concentration of chlorpropham and prochloraz increased during incubation at 20℃, and the inhibition rate was 98.2% and 100% when treated with 503.8 ppm of chlorpropham and 10ppm of prochloraz in 14 days, respectively. Potato Dano tubers inoculated with F. oxysporum were dipped in chlorpropham (5.0, 50.4, and 503.8 ppm) and prochloraz (100 ppm) to investigate the effect of preventing dry rot during cold storage at 20℃ and 4℃ in vivo. The disease diameter of potatoes stored at room temperature (about 20℃) was reduced to 13.0 mm in the prochloraz 100 ppm teatment, and 10.7 mm in the chlorpropham 50.4 ppm treatment compared to 13.7 mm in the control tuber at 70 days of storage. The disease progression in all treatments including control was similar with no statistically significant difference at 4℃ air temperature. From the results of this study, it is considered that treatment with 50.4 ppm of chlorpropham after harvest will be useful for suppressing dry rot of stored potatoes.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.172-180
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• 2023

This study was carried out to determine the sprouting period of early and mid-season varieties, which includes 'Atlantic', 'Chubaek', and 'Superior', during the summer storage period in a semi-underground warehouse without cooling system. And also it was investigated the effect of chlorpropham [Propan-2-yl N-(3-chlorophenyl)carbamate, CIPC] treatment on the sprouting inhibition for the varieties. This study was conducted to figure out a sprout inhibitory effect when CIPC was applied to 1kg of the potato tubers at concentrations of 10 mg and 20 mg which are lower than the treatment concentrations of ca 30 mg prescribed by the positive list system (PLS). The internal temperature of the warehouse used in this experiment was lowered by 5℃ or more than the outside temperature. The difference between the lowest and highest temperature during the experiment throughout the day was 5℃. It showed the effect of reducing to 1/2 of the difference in outdoor temperature. As for the sprouting of potatoes, the extremely early variety 'Chubaek' sprouts appeared at the 6th week of storage of control and it was the fastest sprouting potato among the control groups of the varieties. Sprouting began to appear in the Superior at the 6th week of storage, while the 'Atlantic' sprouted at the 8th week of storage. The appearance of sprouts was suppressed in all treatment groups of 'Atlantic' and 'Superior' varieties in CIPC treatments. Sprouts were observed in all treatment groups of 'Chubaek' after the 7th week, but the elongations of the sprouts in tubers were completely inhibited until the 8th week of storage. 'Atlantic' and 'Superior' seemed to have a sprouting inhibitory effect even with a low CIPC concentration of 10 mg·kg^-1, with the exception of extremely early variety 'Chubaek' that breaks out of the dormancy quickly. Although weight loss occurred continuously during storage, it was minor loss of 0.7-1.6%. There was no consistent trend for changes of the loss in the varieties and CIPC treatments. Most common pathological disorder was the dry rot during the experiment, but only few were affected. The use of the tubers treated at 18℃ and 90% RH for 10 days and the rack of refrigeration system which lead to lack of convection seemed to have suppressed the spread of pathogens.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.1
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• pp.35-41
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• 2023

This experiment was carried out to examine double cropping system using Italian ryegrass (IRG) 'Kowinearly', whole crop rice 'Yeongwoo' and barnyard millet 'Jeju native' during the Oct. 2020 to Oct. 2022. Three kinds of forage crops were cultivated at paddy field in Livestock Institute, Jeollanamdo Agricultural Research and Extension Services, Jeollanamdo, South Korea. Whole crop rice (WCR) was sown in late May and barnyard millet (BM) sown early June each year after harvesting IRG. We examined dry matter yield and feed value of forage crops depending on harvest time of forage crops during the experimental period. The plant height in heading stage of IRG ranged from 108 to 112cm and dry matter yield ranged from 6,783 to 11,530 kg ha^-1. The crude protein (CP) of IRG ranged from 6.0 to 8.44%, acid detergent fiber (ADF) ranged from 55.6 to 60.2% and neutral detergent fiber (NDF) ranged from 32.58 to 36.7%, The dry matter yield of WCR increased as the harvest stage was delayed (14,310 kg ha^-1 in milk, 16,167 kg ha^-1 in yellow ripen, and 18,891 kg ha^-1 in mature). Similar to results of dry matter yield of WCR, dry matter yield of BM increased as the harvest stage was delayed (11,194 kg ha^-1 in late heading. and 14,308 kg ha^-1 in mature), However nutrient content of WCR and BM showed a decreasing trend. As shown in above results, the productivity of WCR after harvesting IRG was shown to be high at paddy field in the southern region. However, BM also was appeared to have potential as summer forage crops.