• Korean Journal of Soil Science and Fertilizer
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• v.36 no.6
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• pp.376-383
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• 2003

To utilize composts more efficiently, combining composts with fertilizer to meet crop requirements is an appealing alternative. A pot experiment was conducted to study the effect of application rate of composted pig manure blended with fertilizer on the availability and loss of fertilizer-N. Chinese cabbage (Brassica campestris L. cv. Samjin) plants were cultivated for 30 and 60 days. 15N-Labeled urea ($5.24\;^{15}N\;atom\;%$) was added to soil at $450mg\;N\;kg^{-1}$, and unlabeled compost ($0.37\;^{15}N\;atom\;%$) was added at 0, 200, 400, and $600mg\;N\;kg^{-1}$. The amount of plant-N derived from urea was not affected by compost application at rate of $200mg\;N\;kg^{-1}$. However, compost application at 400 and $600mg\;N\;kg^{-1}$ significantly (P<0.05) increased plant assimilation of N from urea irrespective of sampling time, probably because of physicochemical changes in the soil properties allowing urea-N to be assimilated more efficiently. The amount of immobilized urea-N increased with increasing rate of compost application at both growth periods, as the results of increased microbial activities using organic C in the compost. Total recovery of urea-N (as percentage of added N) by Chinese cabbage and soil also increased with increasing rate of compost from 71.5 to 95.6% and from 67.0 to 88.2% at the 30- and 60-days of growth, respectively. These results suggest that increasing rate of compost blending increases plant uptake of fertilizer-N and enhances immobilization of fertilizer-N, which leads to decrease in loss of fertilizer-N. However, information about the fate of immobilized N during future crop cultivation is necessary to verify long-term effect of compost blending.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.441-448
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• 2012

This study was carried out to evaluate the productivity of rice cultivation in extremely late season in Korea and to confirm the effects of pot-raising seedling culture in this case by assessing the growth and yield performance of rice cultivars that are well adapted to late culture. Suitable cultivars for extremely late culture should not have premature heading habit when transplanted around late July and also secure appropriate growth duration before heading. Geumobyeo 1 and Manjongbyeo showed small decrease in the emerged leaves in transplanting in late July or early August and heading occurred at the same time relatively without premature heading. At transplanting from late July to early August in extremely late rice cultivation, ripening was relatively good until transplanting on August 5. At transplanting on July 30, accumulated temperature from heading to the first frost was $853^{\circ}C$ and ripening was good enough. However, heading was delayed by low temperature at transplanting on August 10 and ripening was very poor due to low accumulated temperature of below $800^{\circ}C$, causing drastic decrease of rice yield. The rice yield increased in transplanting with pot seedling, especially the effects of pot seedling was higher in Geumobyeo 1, but panicle number was not enough to secure rice yield owing to short growth duration. In order to cultivate rice in extremely late season, we should select adaptive rice cultivars that have suitable growth duration and excellent ripening in low temperature. Here, pot-seedling did a great role to secure early growth and bigger growth amounts.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2001.10a
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• pp.207-218
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• 2001

미국의 콘벨트와 같이 곡물을 집약적으로 재배하는 지역에서 관행생산으로부터 유기적 생산으로 전환할 때 문제가 되는 것은 어떻게 하면 작물윤작을 더 많은 이익이 나올 수 있도록 선택하고 관리하는가 하는 점이다. 곡물생산을 중단하고 사료와 녹비작물을 재배하는데 드는 기회비용은 상당하다. 많은 유기농업 연구자, 학자들은 가축사육을 농장에 도입하여 다양화와 노동력 활용도를 높일 필요가 있음을 강조하고 있다. 가축 역시 곡물생산량이 줄어드는 것을 보완해줄 정도로 곡물 및 사료작물의 가치를 늘려 추며, 곡물생산에 쓰여진 양분을 퇴비를 통해 재활용할 수 있게 해 준다. 곡물 집약재배 지역에서 유기농가는 양돈이 경종체계에 자연스럽게 들어맞는 것으로 생각해 볼 필요가 있다. 돼지는 곡물과 사료작물 모두에 가치를 증대시켜 줄 수 있는 아주 효율적이고 적용이 쉬운 가축이다. 그다지 많지는 않지만 유기적, 지속가능한 양돈 생산에 관해서는 문헌이 좀 있다. 그러나 유기농가로 하여금 유기양돈 생산을 하도록, 그리고 유통의 방법을 어떻게 할 것인가 결정을 내리는데 도움을 줄 수 있는 그런 비교적 구체적인 정보는 그리 많지 않다. 이 글의 주요 초점은 미국 중부지방에서의 유기축산 생산(주로 돼지)에 관한 배경과, 시장의 추세, 인구적 특성, 미국의 기준들에 비추어 생산과 유통에 관한 결정 및 고려사항들에 대한 개관을 제시해 보는 일이다. 농장 수준에서 의사결정은 토지, 노동, 금융과 사회적 자본과 같은 자원을 각종 기회와 더불어 고려하여 이루어져야 한다. 이러한 결정은 모두 농장 차원을 넘어 각종 기준과 시장에서의 세력들의 맥락을 보고 이루어져야 한다. 각 개인의 수준에서는 농업인 역시 유기 흑은 환경친화적 농업에 관한 확신, 바꾸어 보겠다는 결심, 생활양식과 가족에 대한 영향, 그리고 농업인과 가족 경영에 대한 계획의 지평이라고 하는 범위 내에서의 유기적 방식으로의 전환에 관하여 결정을 내려야 한다.aotic motion)의 해석도 가능하다. 이 글에서는 비선형 진동해석을 위한 정규모드 동역학에 대한 연구동향 및 기본 이론을 살펴 보았고, 그 적용 예를 통하여 실험결과와 비교 고찰 함으로써 정규모드 동역학의 적용성을 서술하여 보았다. 선형이론으로 이해하기 어려운 현상들에 대하여는 비선형의 관점에서 새롭게 접근하 려는 노력이 필요하며 비선형 이론에 대한 연구가 지속적으로 진행되어야 한다. 진행되어야 한다.VA코드를 사용하여 흡기포트와 연소실 그리고 밸브의 움직임을 동시에 고려한 수치해석을 도입하였다. 하지만 이들이 밸브의 운동을 고려하기 위해 사용한 이동격자는 격자점은 시간에 따라 변화하지만 그 격자의 수가 일정하게 유지되어 있어서 밸브의 완전개폐를 해석할 수가 없다. 강희정[6]은 단일 실린더와 단일 배기밸브를 갖는 문제로 단순화하여 피스톤과 밸브의 움직임을 고려하므로써 배기행정 후 소음이 어떻게 전파해 나가는가를 연구하였다. 본 연구에서도 최소밸브간격과 최대밸브간격 사이에서만 계산이 가능하나 흡기의 경우는 밸브가 닫힐 때 생기는 압력파가 중요하므로 실린더와 밸브사이에 벽면조건을 주어 밸브의 개폐를 모사하였다.술을 보유하고자 한다. 이용한 해마의 부피측정은 해마경화증 환자의 진단에 있어 육안적인 MR 진단이 어려운 제한된 경우에만 실제적 도움을 줄 수 있는 보조적인 방법으로 생각된다.ofile whereas relaxivity at high field is not affected by τS. On the other hand, the change in τV does not affect low field profile but strongly in fluences on both inflection fie이 and the maximum relaxivity value. The results shows a fluences on both inflection field and the maximu

• Research in Plant Disease
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• v.23 no.2
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• pp.168-176
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• 2017

Root-dipping inoculation method has been widely used to determine the resistance of watermelon to Fusarium oxysporum f. sp. niveum causing Fusarium wilt. Although this method leads to the precise results of plant disease responses, more rapid and efficient assay methods have been still required because the root-dipping inoculation method is labor-intensive and time-consuming. In this study, we established a simple and effective bioassay method based on the comparison of various inoculation methods and growth conditions. To develop the system, the occurrence of Fusarium wilt on four resistant and susceptible cultivars was investigated by four different inoculation methods, root-dipping, scalpel, tip and soil-drenching methods. Of these inoculation methods, scalpel method resulted in clear plant disease resistance responses with the simplicity. With the use of scalpel method, we also explored the disease development of the cultivars depending on inoculum concentration, growth stage of seedlings, and incubation temperature after inoculation. Furthermore, we found that the resistance degrees of 23 cultivars derived by scalpel inoculation method were similar to the results by root-dipping method established previously.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.157-162
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• 2002

The efficient timer-controlled irrigation and the favorable fruiting position were investigated far highly quality melon fruits from Feb.18 to July Si 1999. The nutrient solution was supplied either at every hour from 6：00 to 18：00 (T-1) or at 6：00, 8：00, 10：00, 11：00, 12：00, 12：30, 13：00, 13：30, 14：00, 14：30, IS：00,16：00, and 17：00 (T-2). A fruit was set at the first node of the fruit bearing branch from the 10, 12, or 13th node of the main stem. Pot weight was maintained at almost n constant level, regardless of the daily integrated solar radiation in T-2. Soluble solids content (SSC) and fresh weight of fruit were not significantly different among the irrigation treatments at each harvesting time. At the first harvest, SSC and fresh weight of fruit were not significantly different between the fruiting positions within the irrigation treatment. At the second harvest, SSC was higher in T-2 than T-1. The SSC was low in the fruit of the loth node in T-1, while it was not significantly different between fruiting positions in T-2. Fruit fresh weight was the highest at the 12 and 13th nodes in T-1, and the 13th node in T-2. Fresh and dry weights of leaf except petiole, regardless of harvesting time, increased as the node position was higher, The higher the fruiting position was, the lower the leaf weight was. Therefore, it is recommended to irrigate more frequently during the mid-noon. Fruits can be harvested earlier at the lower nodes in the spring crop production.

• Korean Journal of Environmental Agriculture
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• v.26 no.3
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• pp.223-227
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• 2007

This study was carried out to establish the reasonable level of nitrogen (N) fertilization based on soil nitrate nitrogen $(NO_3-N)$ content for cucumber (Cucumis sativus L.) under plastic film house. Cucumber plants were cultivated with standard and free N fertilization in eight soils which had various amount of $NO_3-N$ ranging from 67 to 343 mg/kg. The yield of cucumber was in the range of 1006 to 2369 g/plant depending on the nitrogen supplying capability of soils. The amount of $NO_3-N$ in the soil was negatively correlated with agronomic efficiency (AE) and N use efficiency (NUE). The critical level of soil $NO_3-N$ content for cucumber in N free fertilization was found to be about 260 mg/kg in Cate-Nelson analysis of variance between soil $NO_3-N$ and AE or NUE. Also the same critical soil $NO_3-N$ content was found in the yield and amount of N uptake of cucumber under N free fertilization. A standard N fertilization was required when soil $NO_3-N$ content was below 70 mg/kg. The optimal application rate of N fertilizer for cucumber in the soils containing $NO_3-N$ between 260-70 mg/kg could be recommended by the equation Y=-1.032X+269.2 (Y: N fertilization rate, kg/ha; X : soil $NO_3-N$ content mg/kg).

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.23-23
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• 2018

본 연구는 참우드풀과 우드풀의 중간형으로 알려진 좀우드풀(Woodsia intermedia Tagawa)의 전엽체 증식 및 포자체 형성을 위한 기내 외 번식조건을 구명하고자 수행되었다. 실험재료는 포자를 발아시켜 획득한 전엽체를 8주 간격으로 계대배양하면서 확보하였다. 전엽체 증식에 적합한 배양조건을 탐색하고자, 전엽체 300mg을 다진 후 배지종류(Knop, 1/4, 1/2 및 1MS)와 배지구성물질(sucrose와 활성탄)의 농도를 달리하여 8주간 배양하였다. 배양실은 온도 $25{\pm}1.0^{\circ}C$와 광도 $30{\pm}1.0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$(16/8h)로 조절되었다. 연구결과, Knop배지에서 생체중이 2.4g으로 전엽체의 증식이 가장 왕성하였다. 한편 MS계열 배지는 농도에 관계없이 매우 저조한 증식을 보였다. Sucrose는 0.5%를 첨가한 배지에서 생체중의 증가량이 가장 컸으며, 활성탄은 첨가농도에 관계없이 유사한 증식수준을 나타냈다. 포자체 형성에 적합한 토양조건을 확인하고자, 인공토양(원예상토, 피트모스, 펄라이트 및 마사토)의 비율을 달리하여 5종류의 혼합토양을 조성하였다. 혼합토양을 사각분($7.5{\times}7.5{\times}7.5cm$)에 충진하고, 준비된 전엽체 1g을 10초간 분쇄한 다음 토양표면에 분주하여 11주간 재배하였다. 재배환경은 온도 $25{\pm}1.0^{\circ}C$, 광도 $43{\pm}2.0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$(16/8h) 및 습도 $72{\pm}2.0%$로 조절되었다. 연구결과, 모든 처리구에서 포자체의 형성이 확인되었으며, 특히 원예상토와 마사토를 2:1(v:v)로 혼합한 토양에서 포트당 421.0개의 많은 포자체가 형성되었다. 다음으로 원예상토와 펄라이트를 2:1(v:v)로 혼용한 토양, 원예상토, 피트모스, 마사토를 1:1:1(v:v:v)로 혼합한 토양, 원예상토 단용, 원예상토, 피트모스, 펄라이트를 1:1:1(v:v:v)로 혼합한 토양 순으로 각 228.0, 203.3, 126.8, 91.5개 형성되었다. 따라서 좀우드풀의 포자체를 대량으로 생산하기 위해서는 원예상토와 마사토를 2:1(v:v)로 혼용한 토양에 전엽체를 분주하여 재배하는 방법이 효과적일 것으로 판단된다.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.110-116
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• 2013

This study was carried out to establish the simple mass-screening methods for resistant tomato to Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL). Root dip inoculation method has been used in many studies on the resistance of tomato to disease. On the other hand, in mass-screening for resistant tomato to Fusarium wilt, the inoculation method is time-consuming and laborious procedure. Disease development of two FOL isolates on two cultivars of tomato according to inoculation method including root dip, tip and scalpel methods were investigated. In compatible interaction, tomato seedlings of each cultivar inoculated by tip method showed the lower and more variable disease severities than by root dip method. Whereas the seedlings by scalpel method represented clear resistant and susceptible responses to Fusarium wilt as root dip method. The resistance degree of each cultivar inoculated with FOL isolates by scalpel method was hardly affected by the tested incubation temperature and inoculum concentration. On the basis of the results, we suggest scalpel inoculation method as an efficient mass-screening method for resistant of tomato cultivars to Fusarium wilt. Roots of tomato seedlings at two-leaf stage grown in plastic cell tray were injured with scalpel and then spore suspension (more than $1{\times}10^7\;conidia{\cdot}mL^{-1}$) of FOL was poured directly on the roots. The infected plants were cultivated in a growth room at $25-30^{\circ}C$ for 4 weeks with 12-hours light a day.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.497-503
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• 2018

A strawberry variety 'Arihyang' was derived as an artificial cross between 'Tochiotome' and 'Seolhyang' in 2014. The seedling and line selections were conducted from 2014 to 2015. Preliminary and advanced yield trials of '14-5-5,' which was the final selected line, were conducted from 2015 to 2017. 'Arihyang' is suitable for forced cultivation and has strong plant vigor, uniformly large-sized fruit, and a high yield compared to those of the check variety, 'Seolhyang' and 'Maehyang.' Especially, vitamin C was at a significant level, which was approximately 15% higher than that of 'Seolhyang.' The average number of flowers per first flower cluster was 10.5, which could reduce the labor of thinning fruit. Its fruit has a conical shape, dark red color, and glossy skin. The fruit was of good quality but has recommendations for harvest at the fully ripened stage. 'Arihyang' has intermediate resistant to phytophthora crown rot, but is susceptible to powdery mildew, gray mold, anthracnose, and fusarium wilt. It is reguired to manage major diseases and pests using optimum cultivation techniques and chemical control.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.658-667
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• 2015

This research was conducted to investigate the influence of various levels of fused superphosphate as pre-planting fertilizer on the growth of red-leaf lettuce and changes in the chemical properties of the soil solution in three root media, namely coir-dust plus expanded rice hull (8:2, v/v; CD+ERH), carbonized rice hull (6:4; CD+CRH), or ground and aged pine bark (8:2; CD+GAPB). The amounts of fused superphosphate (FSP) incorporated into the three root media during formulation were controlled from 0 to $6.0g{\cdot}L^{-1}$ in $1.5g{\cdot}L^{-1}$ increments. The root media containing fertilizers were packed into 300 mL plastic pots and seedlings of red-leaf lettuce at the 3rd leaf stage were transplanted. After transplanting, the crops were fed with a solution of neutral fertilizer ($100mg{\cdot}L^{-1}$). The growth of red-leaf lettuce was investigated 5 weeks after transplanting and soil solutions were extracted and analyzed every week for pH, EC, and concentrations of macro-nutrients. The elevation of application rates of FSP in the three root media resulted in better growth, and the crops grown in CD+ERH and CD+GRPB had greater fresh and dry weights than those in CD+CRH when compared among the treatments of equal amounts of FSP. The pH and $PO_4{^{-3}}$ concentrations in the soil solution of CD+CRH at 3 weeks after transplant were in the ranges of 4.0 to 4.8 and 20 to $100mg{\cdot}L^{-1}$, respectively. These were lower pH and higher $PO_4{^{-3}}$ concentrations than those in CD+ERH and CD+GAPB. The $K^+$ concentrations were higher in CD+CRH than those in the other two root media, and the elevation of FSP application rates resulted in higher $Ca^{+2}$, $Mg^{+2}$ and $SO_4{^{-2}}$ concentrations in soil solution of the three root media. The $NO_3$-N concentrations in soil solution rose continuously during crop cultivation, implying that the leaching percentage was elevated. The soil solution EC varied, showing the same tendencies as the $NO_3$-N concentrations. The above results indicated that the CD+ERH and CD+GRPB media performed better than CD+CRH, and optimum application rates of FSP in the three root media were 4.5 to $6.0g{\cdot}L^{-1}$ for pot cultivation of red-leaf lettuce.