• Korean Journal of Soil Science and Fertilizer
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• v.48 no.4
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• pp.295-304
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• 2015

To develop a technique for efficient management of fertility for cucumber in greenhouse, a quick test method to quantify nitrate ($NO_3{^-}$) content in soil solution and leaf petiole juice using a simple instrument that are easy to use for farmers was investigated. N fertilizer (urea) was applied at 0, 50, 100 and 200% levels of the recommended application rate from 30 days after transplanting to harvest by soil fertigation treatments. Stable results were obtained from analysis of nitrate ($NO_3{^-}$) using top $10^{th}$ or $11^{th}$ leaf petioles collected between 10 to 11 am in the morning. Under the semiforcing culture, $NO_3{^-}$ content of leaf petiole juice was highest at 60 days after transplanting (DAT) at all fertigation treatments. Appropriate $NO_3{^-}$content of leaf petiole juice was $2,418{\pm}78{\sim}2,668{\pm}118$ at 45 DAT, $3,032{\pm}90{\sim}3,332{\pm}63$ at 60 DAT, $2,709{\pm}50{\sim}3,158{\pm}155$ at 75 DAT, $2,535{\pm}49{\sim}2,907{\pm}83$ at 90 DAT, and $2,242{\pm}48mg\;L^{-1}$ at 105 DAT. In addition, appropriate $NO_3{^-}$ content of soil solution was $167{\pm}9{\sim}212{\pm}15$ at 45 DAT, $83{\pm}10{\sim}112{\pm}12$ at 60 DAT, $49{\pm}3{\sim}92{\pm}6$ at 75 DAT, $71{\pm}9{\sim}103{\pm}9$ at 90 DAT, and $73{\pm}9mg\;L^{-1}$ at 105 DAT. The cucumber yield at 100% N level of fertigation was $7,770kg\;10a^{-1}$ and no difference in yield was found at 200% N level of fertigation. However, there was 12% decrease in yield at 50% N fertigation and, 17% decrease at 0% N fertigation. Under retarding culture, $NO_3{^-}$ concentration of leaf petiole juice was highest at 55 days after transplanting (DAT) at all fertigation treatments. Appropriate $NO_3{^-}$ content of leaf petiole juice was $2,464{\pm}102{\sim}2,651{\pm}33$ at 45 DAT, $3,025{\pm}71{\sim}3,314{\pm}84$ at 55 DAT and $2,488{\pm}92mg\;L^{-1}$ at 65 DAT, respectively. Appropriate $NO_3{^-}$ content of soil solution was $111{\pm}10{\sim}155{\pm}14$ at 45 DAT, $93{\pm}7{\sim}147{\pm}14$ at 55 DAT, $67{\pm}4mg\;L^{-1}$at 65 DAT, respectively. The cucumber yield at 50% N fertigation was not different from $1,697kg\;10a^{-1}$ of 100% N fertigation level and even with that of the 200% N fertigation. However, there was 21% decrease in yield at 0% N fertigation.

• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.391-398
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• 1997

Present study describes a method on the application of efficient tissue culture systems for the micro-propagation of juvenile and mature sawtooth oak(Quercus acutissima). Nodal segments with axillary buds were used as initial explant sources. WPM(Woody Plant Medium) was the best in growth and proliferation of shoot among the media tested. Although the single effect of zeatin revealed on two dorminant shoot elongation with normal growth until the elevation of levels up to 3.0mg/l, BAP($N^6$-benzyl amino purine) usually showed better response than zeatin on shoot multiplication and/or elongation. In addition, the incorporation of BAP and zeatin onto the culture media represents more effectiveness in shoot proliferation and its growth. Optimum concentrations of BAP and zeatin were 0.5 and 0.05~1.0mg/l, respectively. Ninety percent of the proliferated shoots was rooted on half-strength GD (Gresshoff and Doy, 1972) medium containing 0.5mg/l IBA(indole butyric acid) in 4 weeks after culture. More than 70% of the rooted plantlets survived after 5 months of transplanting into artificial soil mix containing equal amount of peatmoss and perlite. Among 27 plus tree clones which were grafted twice onto the juvenile rootstocks, only 4 clones revealed the possibility for shoot multiplication through tissue culture system. The capacity for the micropropagation using mature explant sources was highly depended on clonal differences compared with those of octet age. More than 90% of rooting ratio was obtained from the best responding clone. Among the 7 rooting media tested, GD medium was the best far rooting. The most effective rooting was obtained on half-strength GD medium containing 0.2 to 2.0mg/l IBA. More than 60% of rooted plantlets survived after 5 months of transplanting into the artificial soil mix.

• Journal of Radiation Protection and Research
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• v.28 no.4
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• pp.271-279
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• 2003

Soil blocks were taken into culture boxes from 12 paddy fields within 5 km radii of Yonggwang and Ulchin NPPs and $^{90}Sr$ was applied to the surface water at a pre-transplanting stage and $1{\sim}2$ days before the start of heading. Following the pre-transplanting application, transfer factors were investigated for $2{\sim}4$ years. In the year of application, transfer factors $(m^2\;kg^{-1}-dry)\;of\;^{90}Sr$ applied before transplanting, showing no regionally distinguishable trend, varied with soils by a factor of about 2 with averages of $2.6{\times}10^{-4}$ for hulled seeds and $1.3{\times}10^{-2}$ for straw Transfer factors of $^{90}Sr$ applied shortly before heading were about 2 times greater than those applied before transplanting. Transfer factors tended to decrease with increasing soil pH and exchangeable Ca. Generic values of $^{90}Sr$ transfer factors in the year of deposition were proposed for the Korean paddy fields. In the second year compared with the first year, the transfer factor decreased more in Ulchin soils, which were on the whole higher in sand content, than in Yonggwang soils. For Yonggwang soils as a whole, the annual decrease in transfer factor was well described by an exponential equation with a half-life of about 2.2 years.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.122-129
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• 2002

The removal rate of heavy metals from the wastewater, the accumulation and translocation of heavy metals in plants after transplanting, and the responses of water celery growth with different wastewater treatments were investigated to determine the potential ability of green-remediation with hydroponic culture of water celery. The removal rate and translocation of Cd, Cu, Ni and Pb from different wastewater to plants were compared with cultivation periods after transplanting. The removal rate of heavy metals from wastewater was different with each treatment but increased with growing periods of water celery plants. The removal rate of Cd, Cu, Ni and Pb in Artificial solution, Artificial solution+EDTA, Munmark industrical wastewater, Jungsun minewater is ranged from 22 to 73%, from 28 to 100%, from 13 to 92% and from 41 to 100% at 6 days after transplanting, respectively. The translocations of Cd, Cu, Ni and Pb from roots to shoots in Artificial solution, Artificial solution+EDTA, Munmark industrical wastewater, Jungsun minewater are ranged from 14 to 28%. 8 to 30%. from 28 to 45% and from 2 to 15% at 12 days after transplanting, respectively. In plant growth responses, it appears to be inhibited the plant growth over all treatments excepts for Munmark industrial wastewater in these glowing periods. Therefore the water celery might play a useful role in phytoremediation to clean up wastewater contaminated with Cd, Cu, Ni or Pb.

• Current Research on Agriculture and Life Sciences
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• v.7
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• pp.201-219
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• 1989

Rice culture in Korea has a long history ranging over two thousand years. In the agriculture economy of pre-mordern Korea, however, its importantce was not as great as generally assumed. In fact, rice culture reached full development only after the 1920s when the Japanese colonial government carried out its drive to increase rice production in the Korea peninsula. It was not until the mid-1930s that rice became the staple in Korean diet. This can be attributed to two factors : (1) a mountainous topography that provides little irrigated fields and (2) a climate characterized by droughts in spring and heavy precipitation in summer. The present paper attempts to answer some of these questions. Specifically it will focus on these : Did the development of rice culture actually result in population growth? What are the salient features of agricultural develdpment and population grow in traditional Korea? Does the case of Korea conform the prevailing generalization about the agriculture in East Asia? I have discussed the development of rice culture and population growth in the Chos$\breve{o}$n dynasty, focusing on the relation between the rapid spread of transplanting and the rapid growth of population from the seventeenth to the nineteenth century. Here are my conclusions. (1) The spread of transplanting and other technological innovationsc contributed to the rapid growth of population in this period. However, we should also note that the impact of rice culture on population growth was rather limited, for rice culture was not the mainstay of agricultural economy in pre-modern Korea. Indeed we should consider the influence of dry field cropsn population growth. Nevertheless, it is obvious that the proliferation of rice culture was a factor crucial to population growth and regional concentration. (2) How should we characterize the spread of rice culture in the whole period? Evidently rice culture spread from less then 20% of cultivated fields in the fifteenth century to about 36% of them in the early twentieth century. Although rice as a single crop outweighed other crops, rice culture was more then counter-balanced by dry field crops as a whole, due to Korea's unique climate and geography. Thus what we have here in not a typical case of competition between rice culture and day field culture. Besides, the spread of rice culture in the seventeenth and eighteenth centuries accomplished by technological innovations that overcame severe springtime drought, rather than extensive irrigation. Althougt irrigarion facilities did proliferate to some extent, this was achieved by local landlords and peasants rather than the state. This fact contradicts the classical thesis that the productivity of rice culture increased through the state management of irrigation and that this in turn determined the type of society. (3) We should further study other aspects of the transition from the stable population and production struture in the fifteenth and sixteenth centuries to the rapid population growth and excessive density of population thereafter. We should note that there were continuing efforts to reclaim the land in order to solve the severe shortage of land. Changes also took place in the agricultural production relations. The increase in land producrivity developed tenancy based on rent in kind, and this in turn increased the independence of tenants from their landlords. There were changes in family relations-such as the shift to primogeniture as an effort to prevent progressive division of property among multiplying offspring. The rapid population growth also produced a great mass of propertyless farm laborers. These changes had much to do with the disintegration of traditional social institutions and political structure toward the end of the Chos$\breve{o}$n dynasty.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.2
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• pp.94-104
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• 2001

A pilot study was performed at the experimental field of Konkuk University in Seoul, to examine the feasibility of the constructed wetland system for sewage and the effect of treated sewage irrigation on the paddy rice culture and its soil characteristics. The constructed wetland performed well, in that effluent concentrations of pollutants were significantly lower than concentrations of the influent. Median removal efficiencies of BOD$_{5}$ was about 78% and slightly lower during winter. Removal efficiencies form TN and TP were approximately 48 and 21%, respectively, and relatively less effective than that of BOD$_{5}$. Irrigation of treated sewage to paddy rice culture did not affect adversely in both growth and yield of rice. Instead, plots of treated sewage irrigation showed up to 50% more yield in average than the control plot. It implies that treated sewage irrigation might be beneficial to rice culture rather than detrimental as long as it is treated adequately and used properly. Soil was sampled and analyzed before transplanting and after harvesting. pH was slightly increased due to irrigation water, but it may not be concerned as long as the treated sewage is within the normal range. EC was increased in first year but decreased in second year, therefore salts accumulation in the soil could be less concerned. OM and CES was slightly increased, which might be beneficial on growing plants. TN did not show apparent pattern. Available phosphorus was decreased after rice culture, but the quantity of phosphorus(TP-available phosphorus) was rather increased which implies that excessive phosphorus supply may result in phosphorus accumulation in the soil. Overall, the constructed wetland was thought to be an effective sewage treatment alternative, and treated sewage could be reused as a supplemental source of irrigation water for paddy rice culture without causing adverse effect as long as it is treated adequately and used properly. For full-scale application, further investigation should be followed on environmental risk assessment, tolerable water quality, and fraction of supplemental irrigation.ion.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.131-135
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• 1995

Physiologically modified stem nodes derived from ex vitro and in vivo explants of hybrid aspen (Populus alba L.X P.grandidentata Michx. 'Crandon') were tested for their multiple shoot regeneration capacity using a broad spectrum dosage of cytokinins. Ex vitro derived stem nodes with excised axillary buds at the time of culture produced 11 to 13 multiple shoots on 20 to 30 $\mu$M zeatin containing Woody Plant Medium (WPM) after 6 weeks. Excision of axillary bud sprouts after 2 weeks of culture and culture of the remaining stem nodes on WPM with 1.0 to 2.0 $\mu$M BA or 10 to 30 $\mu$M zeatin produced 13 to 15 and 7 to 8 shoots per explant, respectively, Multiple tiny shoots were produced when in vivo derived stem nodes (on which all leaves were removed) were cultured on WPM with 30 to 50 $\mu$M 2iP or 20 to 50 $\mu$M zeatin. The greatest number of multiple tiny shoot proliferation (32 to 50 shoots per explant) were obtained when the explants were cultured on media containing 20 $\mu$M zeatin. Successful transplanting of these multiple shoots into the greenhouse and/or nursery was achieved.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.3
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• pp.259-266
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• 2011

To produce cupped oyster sprat consistently, we investigated the efficiency of nine settlement substrates using selective breeding of Pacific oyster Crassostrea gigas, with the goal of popularizing off-bottom culture on the west coast of Korea. We also compared the growth and survival of selectively bred sprat (diploid) with triploid sprat from an off-bottom culture system. Considering, the attachment rate and detachment efficiency, producing cupped oyster in a polypropylene gunny bag proved to be the most effective method. There were no differences in shell growth or total weight between the diploids from selective breeding and triploids from off-bottom culture for 5 months. However, the survival rate was 8 times higher in the diploids than the triploids. Transplanting sprat from selective breeding is one way to restore oyster farms and nurture off-bottom culture along the west coast.

• Korean Journal of Breeding Science
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• v.43 no.6
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• pp.581-586
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• 2011

'Cheongdam' is a japonica rice variety developed from a cross between SR19200-HB826-34, a line of good germination ability and shoot emergence at low temperature and Juanbyeo, good quality and direct-seeding adaptable cultivar by the rice breeding team of National Institute of Crop Science, RDA in 2006. This variety has 153 days of total growth duration from seeding to maturity in direct-seeding, and 160 days of growth duration from seeding to maturity in transplanting. This is erect plant type with culm length of 74 cm, thick culm, and green leaves. It has large panicle shape with 126 and 140 spikelets per panicle in direct-seeding and transplanting, respectively. Milled rice is transluscent and medium in grain size of non-glutinous endosperm. This variety is susceptible to leaf and neck blast, bacterial blight, stripe virus disease and brown planthopper. The yield potential of 'Cheongdam' is 5.84 MT/ha at ordinary transplanting culture and 5.62 MT/ha and 5.89 MT/ha at wet direct-seeding and dry direct-seeding cultures, respectively in the local adaptability test for three years. 'Cheongdam' would be adaptable to middle and southern plain of Korea for direct-seeding culture and transplanting rice culture.

• Korean Journal of Plant Resources
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• v.36 no.2
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• pp.181-190
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• 2023

Domestic hop (Humulus lupulus L.) production has been suspended since the early 1990s due to foreign imports, but interest in local production is rising due to the recent craft beer boom in Korea. This study was conducted focusing on the development of growth characteristics and propagation technology for 6 introduced hop cultivars as a basic study for domestic hop production and breeding program. In the hop growth survey conducted in 2021 and 2022, the 5-year-old plants after planting generally showed a tendency to increase the height of strobile setting, strobile size, number and weight of strobile per hill compared to the 4-year-old plants. As a result of the experiment with hop vine cuttings, the average rooting rate of all cultivars was as high as 88% even in only water treatment that were not added with Atonik (Atonik, Arysta, Japan), a rooting agent. There were differences between cultivars in rooting length and rooting rate according to the Atonik treatment method. When checking the survival rate of the rooted cuttings seedlings after transplanting into the soil, it was confirmed that the survival rate of the cuttings in the tissue culture room was significantly lower than that of the cuttings in the greenhouse. However, in transplanting step, cutting plants from culture room condition was strongly inhibited plant growth because of changing environment conditions. As a results of tissue culture, the thidiazuron (TDZ) 1 ㎎/L treatment in the media generated 6 to 9 shoots/explant, while the 6-benzylaminopurine (BAP) 1 ㎎/L treatment generated only 1 to 2 shoots/explant. Therefore, it is more effective to culture by adding TDZ rather than BAP. These results indicated that the development of technology to manage stably after transplanting of cutting or micropropagating plants into potting soil is important for mass propagation of hops.