• Applied Biological Chemistry
• /
• v.17 no.1
• /
• pp.63-80
• /
• 1974

The chemical components of Citrus junos produced in Korea were divided into two parts; common and special components respectively. In the former the relation between the physiological effects of the plant and its ripening process was observed periodically while the latter was analyzed the ripening fruits for their effective utilization as food. The results are summarized as follows: 1. The analytical result of seasonal change showed that the rind ratio was higher than the flesh ratio and on a regional basis, the rind ratio was higher in the islands than on land areas. 2. In the experiment the moisture was increased until the third period, but afterwards it was made constant. While the content of crude fat, cellulose, ash, total acid and soluble non-nitrogen material were decreased until the third period and the cotent of cellulose and total acid were continuousely redused until the last period. In con trast with the above the content of reducing sugars was increased but the content of crude fat, cellulose, ash, crude protein and soluble non-nitrogen material were increased until last period. 3. The content of vitamin C was richer in the rind than in the flesh, in the Korean species than in the Japanese. 4. Free sugars; xylose, fructose, glucose were richer in the rind than in the flesh. 5. The content of volatile organic acids was richer in the rind than in the flesh. Among them, volatile acids, acetic acid, formic and n-valeric acid were found in the rind and formic acid, acetic acid and propionic acid were deteceed in the flesh. 6. The total content of non-volatile acids was richer in the flesh than in the rind. In the kind of non-volatile acids, citric acid,glutaric acid, malic acid, tartaric acid, oxalic acid, malonic acid, succinic acid and an unknown acid were found in the rind and citric acid, malic acid, succinic acid, oxalic acid, glutaric acid and malonic acid in the flesh. 7. Three kinds of aromatic components: D-limonene, ${\alpha}-pinene$, p-cymene and seven other kinds of unknown aromatic components were detected in neutral essential oils. Among them, D-limonene seemed to be main aromatic component in the fruits. 8. From the above results it is confirmed that both rind and flesh of the ripened fruit could be utilized for food effectively, and unripened fruits are suitable for producing citric acid, ripened fruits are also useful for producing juice.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.35 no.2
• /
• pp.81-86
• /
• 2015

"Youhan" (Hordeum vulgare L.), a new whole-crop barley cultivar, was developed by the breeding team at National Institute of Crop Science, RDA in 2012. Youhan has the growth habit of III, a light green and mid-sized leaf, hooded and lax-type spikes. The cultivar showed 107 cm of culm length, 641 spikes per $m^2$. The heading date of Youhan was May 1, which is one day later than that of the check cultivar "Yuyeon" in upland, and 2 days earlier than that of Yuyeon in paddy field. The maturation time was similar to check cultivar Yuyeon on June 4 in upland and May 31 in paddy field. In terms of winter hardiness and resistance to lodging and disease, Youhan also performed better than the check cultivar. The average forage dry matter (DM) yield in the regional yield trial was approximately 12.6 ton $ha^{-1}$ and 12.0 ton $ha^{-1}$ in upland and paddy field, respectively, which were 6% and 5% higher than that of the check. The yield also showed 7.3% of crude protein, 26.8% of ADF (acid detergent fiber), 47.8% of NDF (neutral detergent fiber), 67.7% of TDN (total digestible nutrients), and a higher grade of silage quality for the whole-crop barley. Fall sowing cropping of Youhan is recommended only in those areas where the average daily minimum-mean temperatures in January are higher than $-8^{\circ}C$, and it should not be cultivated in mountainous areas of Korea.

• Journal of the Korean Geographical Society
• /
• v.41 no.5 s.116
• /
• pp.527-544
• /
• 2006

This study provides a definition of heat waves, which indicate the conditions of strong sultriness in summer, appropriate to Korea and intends to clarify long term(1973-2006) averaged spatial and temporal patterns of annual frequency of heat waves with respect to their intensity. Based on examination of the Korean mortality rate changes due to increase of apparent temperature under hot and humid summer conditions, three consecutive days with at least $32.5^{\circ}C,\;35.5^{\circ}C,\;38.5^{\circ}C,\;and\;41.5^{\circ}C$ of daily maximum Heat Index are defined as the Hot Spell(HS), the Heat Wave(HW), the Strong Heat Wave(SHW), and the Extreme Heat Wave(EHW), respectively. The annual frequency of all categories of heat waves is relatively low in high-elevated regions or on islands adjacent to seas. In contrast, the maximum annual frequency of heat waves during the study period as well as annual average frequency are highest in interior, low-elevated regions along major rivers in South Korea, particularly during the Changma Break period(between late July and mid-August). There is no obvious increasing or decreasing trend in the annual total frequency of all categories of heat waves for the study period However, the maximum annual frequencies of HS days at each weather station were recorded mainly in the 1970s, while most of maximum frequency records of both the HW and the SHW at individual weather stations were observed in the 1990s. It is also revealed that when heat waves occur in South Korea high humidity as well as high temperature contributes to increasing the heat wave intensity by $4.3-9.5^{\circ}C$. These results provide a useful basis to help develop a heat wave warning system appropriate to Korea.

• Korean Journal of Food Science and Technology
• /
• v.39 no.4
• /
• pp.353-359
• /
• 2007

This survey was carried out to estimate the heavy metal contents of fishes (531 ocean fishes and 80 freshwater fishes) sold in and around Korea from April to October in 2006 . The contents of arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), manganese (Mn), zinc (Zn) and mercury (Hg) were estimated by inductively coupled plasma-mass spectrometry (ICP-MS) and a mercury analyzer. The concentrations [mean (minimum-maximum) mg/kg] of heavy metals in the ocean fishes were as follows: As=2.523 (0.140-65.543), Cd=0.017 (0.000-0.108), Cu=0.569 (0.040-5.634), Pb=0.023 (0.000-0.323), Hg=0.068 (0.002-0.754), Mn=0.395 (0.016-4.651) and Zn=6.086 (0.529-34.729). The concentrations of heavy metals in the freshwater fishes were: As=0.370 (0.024-2.231), Cd=0.01l (ND-0.086), Cu=0.628 (0.003-1.962), Pb=0.026 (ND-0.423), Hg=0.058 (0.006-0.349), Mn=1.150 (0.069-7.230) and Zn=9.980 (3.463-82.737). The weekly intakes of Cd, Hg and Pb from fish were 0.9, 1.6 and 0.9%, respectively, as compared with the Provisional Tolerable Weekly Intake (PTWl) established by Joint FAO/WHO Expert Committee for food safety evaluation.

• Korean journal of applied entomology
• /
• v.7
• /
• pp.5-13
• /
• 1969

Present system of seed potato production in Korea has several weak points and consequently has difficulties in covering annual shortage of 60,000 tons of seed potatoes. The author has an opinion that this so called 'High land system' of seed potato production adopted by the Government should be replaced by the 'Coastal area system' which is proposed by the author and has many advantages over present 'High land system'(2). In coastal areas where enormous acreage of rice paddies are spread, mostly around the villages. the primary host plants of the vectors are found. Therefore, the only source of aphid vectors are limited to the villages. The farmer's houses scattered more sparsely also have minor importance. In the previous paper(2), the author reported that the aphid vector populations were lower in the coastalareas than at Taegwanryong where the Alpine Experiment Station for the production. of seed potatoes is located. However, the number to vectors at Okku showed rather high density, where the trap was placed at the distance of 200 m from a village where peach and Hibiscus trees, the primary hosts of Myzus pesrsicae and Aphis gossypii were grown. To clarify the flight distance from the source of the aphid vectors, a trial was carried out in the Kwanghwal area, Kimje-gun, Cholla-pukto. on the western coast. 13 traps were placed at four directions and the distances between the traps were 250 m. (Fig. I) The traps 'Were operated from June 21 to October 31. The results are shown in Table 1. A total of some 70 species of aphids were found, including 5 speceis of potato virus vectors. The vectors are as follows: I. Myzus persicae (Sulzer) 2. Aphis gossypii Glover 3. Aulacorthum solani (Kaltenbach) 4. Lipaphis erysimi (Kaltenbach) 5. Macrosiphoniella sanborni (Gillette) Out of a total of 12,797 aphids, 5,187$(48\%)$ vectors were found. The trap catches at the 13 locations are shown in Fig. 2 and the numbers of the vectors at each location for each vector, except Macro-siphoniella sanborni. of which only a single individual was caught, are shown in Fig. 3-6. Number of vectors at C (3,279) (Centre of the village) is considerably higher than that at Suwon (763); however, EI. SI. WI and NI. where the distanecs from Care 250 m, showed lower numbers of vectors than that at Taegwanryong (347). The number of vectors at NI was rather than at the other 3 locations at the distance of 250m from the village. This was because C was in the southern part of the village. Consequently NI was much closer to the village than the other 3 locations of the same distance from C. Numbers of catches of the most important vector. Myzus persicae, are shown in Fig.3. The distribution pattern is typical except $S-2\;and\;W_3$, where several farmer's houses were found. If only the rice paddies were found in these locations. the numbers of the vectors would be small as the distances increase. Numbers of catches of the other 3 vectors are shown in Fig. 4-6. From these results. the author has drawn the following conclusions: 1. The aphid vector sources at the rice paddy belt in the western coast are the villages. 2. The vector densities at the locations where the distances are 250 m from the centre of the village are lower than that at Taegwanryong. 3. The vector densities become gradually lower as the distances from the centre of village increase. However. depending on the host plant situation at each location, the vector densities are variable. These minor sources of aphid vectors may be eliminated so that seed potatoes can be grown. 4. Thus. under the direction of specialists, fields suitable for seed potato production can be found in the coastal areas.

• Korean Journal of Environment and Ecology
• /
• v.24 no.1
• /
• pp.14-25
• /
• 2010

This study was carried out to investigate the soil salinity and salt spray drift of the indigenous windbreak trees, and its main purpose was to provide basic data for the selection of salt-tolerant trees in the saline coastal region in the South Sea of Korea. The soil salinity($EC_{1:5}$)was $0.18dSm^{-1}$, which was an average degree of the whole areas of investigation whose salinity degree ranged from $0.05dSm^{-1}$ to $0.58dSm^{-1}$. The level of soil salinity gradually decreased as it moved farther inland, except the belt I. The level of decreasing soil salinity was found to be in the following order: belt II, belt III, belt I, belt IV. The degree of soil salinity was $EC_{1:5}$ $0.22dSm_{1:5}$, $0.22dSm_{1:5}$ $0.19dSm^{-1}$ and $0.13dSm^{-1}$ respectively. The total 110 taxa, which consisted of 45 families, 74 genus, 101 species, and 9 varieties, were found to be tolerant to both soil salinity and salt spray drift. The trees that grow in the highest degree of salinity($EC_{1:5}$ $0.50dSm^{-1}$)were Parthenocissus tricuspidata(Siebold & Zucc.), Planch and Lonicera japonica Thunb. The next group of trees that grow in the high degree of salinity ranging from $EC_{1:5}$ 0.41 to $0.50dSm^{-1}$ was Cudrania tricuspidata(Carr.) Bureau ex Lavall$\acute{e}$e, Rubus parvifolius L., Zanthoxylum schinifolium(Siebold & Zucc.), Hedera rhombea(Miq.) Bean., Robinia pseudoacacia L., Quercus serrata Thunb., Callicarpa dichotoma(Lour.) K. Koch, and so on. The woody species which grew in the entire belts were Pueraria lobata(Willd.) Ohwi and Vitis flexuosa Thunb., and Vitex rotundifolia L. f. which was known to be highly tolerant to salt spray drift was found only in belt I. The woody species with high important value(IV) were Zelkova serrata(Thunb.) Makino., Celtis sinensis Pers., Koelreuteria paniculata Laxmann, Mallotusjaponicus(Thunb.) Muell. Arg., Trachelospermum asiaticum(Siebold & Zucc.) NAKAI, and Pueraria lobata(Willd.) Ohwi. These species were classified as native windbreak trees that are comparatively more tolerant to salt spray drift than other kinds.

• Korean Journal of Soil Science and Fertilizer
• /
• v.17 no.2
• /
• pp.125-133
• /
• 1984

To obtain the basic date for the improvement of cultural and managemental problems caused by soil characteristics and soil productivity in rice cultivation of Honam area, morphological characteristics of rice soils were investigated in Mangeng-Dongjin and Yeongsan Water-sheds, and compaired differences between two major Watersheds. The results obtained are summarized as follows: 1. According to U.S.D.A. Soil Taxonomy Classification System, eight great groups are distributed in rice soils of two major Watersheds. More than 50% of rice paddy soils are classified as Haplaquepts. 2. Two Watersheds are quite different in soil parent materials. In Mangeong-Dongjin Watershed, most soils (55.1%) are derived from fluvic-marine deposits. Remainders are derived from local alluvium (24.7%) and alluvium (14.2%). But in Yeongsan Watershed, the order is local alluvium>alluvium>fluvio-marine deposits. 3. Rice soils occur mostly in coastal and inland flat-site with the slope of less than 2% (57.8%) in Mangeong-Dongjin Watersheds. However, in Yeongsan Watershed, flat-site and low undulating terrace are mostly distributed (52.9%). 4. About 81.9, 61.4 and 53.3% of rice soils are classified as fine textured in Yeongsan, Dongjin, and Mangeong Watersheds, respectively. 5. More normal paddy soils and less sandy paddy soils are distributed in Yeongsan Watershed. The results indicate that more rice soils are classified as productivity classes of I and II in Yeongsan Watershed than in Mangeong-Dongjin Watersheds.

• The Journal of the Petrological Society of Korea
• /
• v.25 no.3
• /
• pp.169-193
• /
• 2016

In order to characterize the Neotectonic crustal deformation and current stress field in and around the Korean Peninsula and to interpret their tectonic implications, this paper synthetically analyzes the previous Quaternary fault and focal mechanism solution data and recent geotechnical in-situ stress data and examines the characteristics of crustal deformations and tectonic settings in and around East Asia after the Miocene. Most of the Quaternary fault outcrops in SE Korea occur along major inherited fault zones and show a NS-striking top-to-the-west thrust geometry, indicating that the faults were produced by local reactivation of appropriately oriented preexisting weaknesses under EW-trending pure compressional stress field. The focal mechanism solutions in and around the Korean Peninsula disclose that strike-slip faulting containing some reverse-slip component and reverse-slip faulting are significantly dominant on land and in sea area, respectively. The P-axes are horizontally clustered in ENE-WSW direction, whereas the T-axes are girdle-distributed in NNW direction. The geotechnical in-situ stress data in South Korea also indicate the ENE-trending maximum horizontal stress. The current crustal deformation in the Korean Peninsula is thus characterized by crustal contraction under regional ENE-WSW or E-W compression stress field. Based on the regional stress trajectories in and around East Asia, the current stress regime is interpreted to have resulted from the cooperation of westward shallow subduction of the Pacific Plate and collision of Indian and Eurasian continents, whereas the Philippine Sea plate have not a decisive effect on the stress-regime in the Korean Peninsula due to its high-angle subduction that resulted in dominant crust extension of the back-arc region. It is also interpreted that the Neotectonic crustal deformation and present-day tectonic setting of East Asia commenced with the change of the Pacific Plate motion during 5~3.2 Ma.

• Journal of Climate Change Research
• /
• v.5 no.2
• /
• pp.127-137
• /
• 2014

The main purpose of this study is to estimate tradial growth response and to predict the potential spatial distribution of major tree species(Pinus densiflora, Quercus mongolica, Quercus spp., Castanea crenata and Larix kaempferi) in South Korea, considering climate and topographic factors. To estimate radial growth response, $5^{th}$ National Forest Inventory data, Topographic Wetness Index (TWI) and climatic data such as temperature and precipitation were used. Also, to predict the potential spatial distribution of major tree species, RCP 8.5 Scenario was applied. By our analysis, it was found that the rising temperature would have negative impacts on radial growth of Pinus densiflora, Castanea crenata and Larix kaempferi, and positive impacts on that of Quercus mongolica, Quercus spp.. Incremental precipitation would have positive effects on radial growth of Pinus densiflora and Quercus mongolica. When radial growth response considered by RCP 8.5 scenario, it was found that the radial growth of Pinus densiflora, Castanea crenata and Larix kaempferi would be more vulnerable than that of Quercus mongolica and Quercus spp. to temperature. According to the climate change scenario, Quercus spp. including Quercus mongolica would be expected to have greater abundance than its present status in South Korea. The result of this study would be helpful for understanding the impact of climatic factors on tree growth and for predicting the distribution of major tree species by climate change in South Korea.

• Korean Journal of Environment and Ecology
• /
• v.33 no.1
• /
• pp.1-8
• /
• 2019

Pintail (Anas acuta) is the major wintering bird in South Korea and known as a major mediator of the highly pathogenic avian influenza (HPAI). Pintail migrates long distances between Russian Siberia and Korea. This species prefers a rice paddy area as their winter habitat. The purpose of this study is to provide the data necessary for the conservation and management of bird habitats in Korea by understanding the wintering home-range and habitat of pintail in Korea. We captured six pintails using a cannon-net in the winter of 2015 and attached the GPS-mobile phone based telemetry (WT-300) on them to study the wintering home-range and wintering habitat. We analyzed the tracking location data using ArcGIS 9.0 Animal Movement Extension and calculated Kernel Density Estimation (KDE) and Minimum Convex Polygon (MCP). The average home-range in the wintering ground analyzed by MCP was $677.3km^2$ (SD=130.2, n=6) while the maximum and minimum were $847.7km^2$ and $467.5km^2$, respectively. Extents of home-range analyzed by KDE were $194.7km^2$ (KDE 90%), $77.4km^2$ (KDE 70%), and $35.3km^2$ (KDE 50%). The pintails mostly used both sea and paddy field as habitat in the winter season and utilized paddy fields more during the nighttime and than the daytime. We concluded that the home-range and habitat of pintails in the winter could be used as the reference data for the preservation of species, management of habitats, and coping with a breakout of HPAI.