• Journal of the Korean Society for Marine Environment & Energy
• /
• v.18 no.3
• /
• pp.166-178
• /
• 2015

We investigated marine environmental characteristics of Goheung coastal areas in August where is known to be the first outbreak site of Cochlodinium polykrikoides (hereafter C. polykrikoides) blooms, based on the oceanographic data observed from 1993 to 2013 around the Korean southern coastal waters including Eastern China Sea by National Fisheries Research and Development Institute (NFRDI). The data of NOAA/NGSST satellite images as well as numerical simulation results by Seo et al. [2013] were also used for analysis. Water temperatures at the surface and bottom layers in Goheung coast, i.e. Narodo, were $25.0^{\circ}C$ and $23.7^{\circ}C$ so that they were higher than $23.8^{\circ}C$ and $19.4^{\circ}C$ in Geoje coast where is a reference site, respectively. In addition, salinities at the surface and bottom layers in Goheung coast were 31.78 psu and 31.98 psu so that they were a little higher than 31.54 psu at the surface but a little lower than 32.79 psu at the bottom in Geoje coast, respectively. That is, the differences in water temperature or salinity between the surface and bottom layers in Goheung coast in August were not large compared to Geoje coast. This suggests that stratification in Goheung coast in August is fairly weak or may not be established. In addition, the concentrations of DIN and DIP at the surface layer were 0.068 mg/L ($4.86{\mu}M$) and 0.015 mg/L ($5.14{\mu}M$) in Goheung coast while 0.072 mg/L ($5.14{\mu}M$) and 0.01 mg/L ($0.32{\mu}M$) in Geoje coast, so they did not indicate a meaningful difference. On the other hand, when C. polykrikoides blooms, water temperature and salinity in August at the station 317-22 ($31.5^{\circ}N$, $124^{\circ}E$) of the East China Sea, where is near the mouth of Yangtze River, were $27.8^{\circ}C$ and 31.61 psu, respectively. Thus, water temperature was much higher whereas salinity was almost similar compared to Goheung coast. Furthermore, concentrations of $NO_3-N$ and $PO_4-P$ in the East China Sea in August were remarkably high compared to Goheung coast. When C. polykrikoides blooms, according to not only the image data of satellites NOAA/NGSST but also numerical experiment results by Seo et al.[2013], the freshwater out of Yangtze River was judged to clearly affect the Korean southern coastal waters. Therefore, the supply of nutrients in terms of Yangtze River may greatly contribute to the outbreak of C. polykrikoides blooms in Goheung coast in summer.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.18 no.3
• /
• pp.143-156
• /
• 2015

In order to understand the dynamic characteristics of water column environments in the Western Pacific seamount area (approximately $150.2^{\circ}E$, $20^{\circ}N$), we investigated the water mass and the behavior of water column parameters such as dissolved oxygen, inorganic nutrients (N, P), and chlorophyll-a. Physico-chemical properties of water column were obtained by CTD system at the nine stations which were selected along the east-west and south-north direction around the seamount (OSM14-2) in October 2014. From the temperature-salinity diagram, the main water masses were separated into North Pacific Tropical Water and Thermocline Water in the surface layer, North Pacific Intermediate Water in the intermediate layer, and North Pacific Deep Water in the bottom layer, respectively. Oxygen minimum zone (OMZ, mean $O_2$ $73.26{\mu}M$), known as dysoxic condition ($O_2<90{\mu}M$), was distributed in the depth range of 700~1,200 m throughout the study area. Inorganic nutrients typified by nitrite + nitrate and phosphate showed the lowest concentration in the surface mixed layer and then gradually increased downward with representing the maximum concentration in the OMZ, with lower N:P ratio (13.7), indicating that the nitrogen is regarded as limiting factor for primary production. Vertical distribution of water column parameters along the east-west and south-north station line around the seamount showed the effect of bottom water inflowing at around 500 m deep in the western and southern region, and concentrations of water column parameters in the bottom layer (below 2,500 m deep) of the western and southern region were differently distributed comparing to those of the other side regions (eastern and northern). The value of Excess N calculated from Redfield ratio (N:P=16:1) represented the negative value throughout the study area, which indicated the nitrogen sink dominant environments, and relative higher value of Excess N observed in the bottom layer of western and southern region. These observations suggest that the topographic features of a seamount influence the circulation of bottom current and its effects play a significant role in determining the behavior of water column environmental parameters.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.38 no.1
• /
• pp.23-29
• /
• 2018

'Dakyeong' (Avena sativa L.), a winter oats for forage use, was developed by the breeding team at National Institute of Crop Science, RDA in 2016. It was derived from a cross between 'CI7505'(IT133304) and 'Swan'(IT197920). Subsequent generations followed by the cross were handled in bulk and pedigree selection programs at Iksan and Jeonju, respectively. After preliminary and advanced yield test for 2 years, 'SO2004009-B-B-10-8-3-9', designated as a line name of 'Gwiri91', were subsequently evaluated for earliness and forage yield during 3 years in four parts such as Jeju (upland), Yesan (upland), Iksan (upland), and Jeonju (paddy), from 2014 to 2016, and finally named as 'Dakyeong'. Cultivar 'Dakyong' has leaves of dark green color, thick diameter culm and long grain of brown color. Over 3 years, the heading date of 'Dakyeong' was about 5 days earlier than that of check cultivar 'Samhan' (April 30 and May 5, respectively), and their average forage dry matter yield harvested at milk-ripe stage was higher 12% ($15.7tone\;ha^{-1}$) than $14.0tone\;ha^{-1}$ of check cultivar. Cultivar 'Dakyeong' was lower than the check cultivar 'Samhan' in terms of the protein content (6.1% and 7.0%, respectively) and total digestible nutrients (62.1%, and 62.5%, respectively), while the TDN yield was more than the check ($7.79tone\;ha^{-1}$ and $7.64tone\;ha^{-1}$, respectively). Fall sowing cropping of 'Dakyeong' is recommended only in areas where average daily minimum mean temperatures in January are higher than $-6^{\circ}C$, and it should not be cultivated in mountain areas, where frost damage is likely to occur.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.38 no.1
• /
• pp.16-22
• /
• 2018

Oats (Avena sativa L.), which are known as one of the forage crops of Korea, have good livestock palatability and are popular to cattle farmers because of their high dry matter. However, the cultivation of double cropping in the rice field was reluctant due to the late maturing for farmers to plant rice continuously. 'Hi-early', a winter oats for forage use, was developed by the breeding team at National Institute of Crop Science, RDA in 2016. It was derived from a cross between '517A2-121'(IT133383) and 'CI7604' (IT133379). Subsequent generations followed by the cross were handled in bulk and pedigree selection programs at Suwon, Iksan and Jeonju, respectively. After preliminary and advance yield test for 2 years, 'SO2004015-B-B-23-1-3-7', designated as a line name of 'Gwiri92', were subsequently evaluated for earliness and forage yield during 3 years in four parts such as Jeju (upland), Yesan (upland), Iksan (upland), and Jeonju (paddy), from 2014 to 2016, and finally named as 'Hi-early'. Cultivar 'Hi-early' has the characteristics of medium leaves of green color, thick diameter culm, and medium grain of brown color. Over 3 years, the heading date of 'Hi-early' was about 9 days earlier than that of check cultivar 'Samhan' (April 26 and May 5, respectively). Average forage fresh yield of 'Hi-early' harvested at milk-ripe stage was similar to check cultivar ($40.2tone\;ha^{-1}$ and 40.0 tone ha-1, respectively), and dry matter yield also was similar to check cultivar (14.2 tone ha-1 and $14.0tone\;ha^{-1}$, respectively). Cultivar 'Hi-early' was lower than the check cultivar 'Samhan' in terms of the protein content (6.2% and 7.0%, respectively) and total digestible nutrients (61.0%, and 62.5%, respectively), while the TDN yield was more than the check ($7.91tone\;ha^{-1}$ and $7.64tone\;ha^{-1}$, respectively). Fall sowing cropping of 'Hi-early' is recommended only in areas where average daily minimum mean temperatures in January are higher than $-6^{\circ}C$, and it should not be cultivated in mountain areas, where frost damage is likely to occur.

• Journal of Aquaculture
• /
• v.11 no.4
• /
• pp.547-556
• /
• 1998

This study was performed to obtain the basic data on the serum constituents of several marine fish spesies commonly cultured in Korea. Blood samples taken from six species of fish were analyzed for various components of serum, total protein (TP), albumin (ALB), triglyceride (TRIG), cholesterol (CHOL), glucose (GLC), lipase (LIPA), amylase (AMYL), aspartate transaminoferase (AST), sodium (Na), potassium (K), chloride (CI) and phosphorus (PHOS). The fish used were coho salmon (Oncorhynchus kisutch), rock fish (Sebastes schlegeli), sea bass (Lateolabrax japonicus), olive flounder (Paralichthys olivaceus), rock fish (Sebastes schlegeli), sea bass (Lateolabrax japonicus), olive flounder (Paralichthys olivaceus), parrot fish (Oplegnathus fasciatus) and jack mackerel (Trachurus jaonicus) reared at the Chungmu Experimental Fish Culture Station of KORDI when the water tempetature was ca. 16.5$^{\circ}C$. There were significant differences in TRIG, CHOL, LIPA and AMYZ among the species analyzed. TRIG concentratin were ranged 178~180mg/dl in jack mackeerel and rock fish, 126~159 mg/dl in olive flounder and sea bass, and 102~114 mg/dl in coho salmon and parrot fish, respectively. Jack mackerel showed the highest levels in CHOL (255mg/dl) and GLC(138mg/dl) among species. LIPA levels were recorded 256 U/dl in coho salmon, 41~42 U/dl in parrot fish and rock fisk, and 5~11 U/dl jack mackerel and sea bass, respectively. AMYL activity of coho salmon was measured as 2, 665 U/dl, and that of jack mackerel was 1,210 U/dl while sea bass showed 60 U/dl and parrot fish, olive flounder and rock fish had at most 5 U/dl. On the other hand, there was no significant difference in the concentration of Na and CI. Na and K were proved that they were negatively correlated in all the species. Generally, among blood components, PHOS and CHOL levels were different depending on environmental temperature of each fish species, especially in olive flounder. Rock fish and parrot fish showed high blood concentration of those components during low temperature period while olive flounder and jack mackerel reached high level during their optimal environmental temperature period. The electrolyte concentration and LIPA activity were high during low water temperature period, in general, but TP and ALB concentrations were high during optimal temperature period. The concentrations of TRIG, CHOL and GLC, those which were used as energy sourses, were different among species by season.

• 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.

• Applied Biological Chemistry
• /
• v.20 no.1
• /
• pp.88-94
• /
• 1977

A laboratory study was made of liming on the extractability of phosphate added to the uncultivated acid soils differing in clay content. The experiments were conducted with different rates of calcium carbonate and triple superphosphate at field capacity and 50% field capacity. The concentration of extractable phosphate was greatly reduced by simultaneous addition of calcium carbonate in the loam soil. When samples of the loam soil were preincubated for ranging from 0 to 50 days in the presence of calcium carbonate prior to phosphate application, the extractable phosphate concentration increased with preincubation time, and more phosphate was extracted from the soil maintained at 50% field capacity during the incubation. However, the extractable phosphate concentration in the sandyloam soil did not change with preincubation time and was not affected by moisture status. It may be concluded that the extractability of added phosphate was influenced by not only liming time but physical properties of soil.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.21 no.6
• /
• pp.778-783
• /
• 2015

We studied about the strength characteristics of the FRP bonding method due to reduce accident on the oceans and protect life for my people. We test tension and bending strength of butt joint, lap joint, V-scarf joint, X-scarf joint. The result of test, it's pattern is similar both tension and bending strength. Tension strength and bending strength was excellent in order to X-scarf-butt joint-V-scarf-lap joint. The tension strength is the best properties X-scarf showed a 57% strength rate of the basic material, and bending strength showed a 77% strength rate of the basic material. Overall, the X-scarf 12t joint has most excellent properties of tension and bending strength. The lap joint has worst properties of tension and bending strength. We have to test having different over-lay of V-scarf and X-scarf joint each 12t, 16t, 20t. V-scarf of 20t over-lay has excellent character of tension and bending strength. But X-scarf of 12t over-lay has excellent character of tension and bending strength. The results are shown to the contrary. The ship is received a lot of stress. it's hard to compare a direction both actual and test. But we can acknowledge material basic characteristic of strength through tension and bending test. We give the four repair method; butt joint, lap joint, V-scarf joint, X-scarf joint and the reduced ratio in comparison with basic material; In addition give the separated data for V-scarf and X-scarf characteristic of 12t, 16t, 20t overlay length. For our study repair man can select good repair method in his work station.

• The Journal of Natural Sciences
• /
• v.8 no.1
• /
• pp.71-80
• /
• 1995

This experiment was conducted to investigate the effect of raising seedling methods of cold water, low night temperature, and abandoned mine on forcing culture of strawberry. The results were as follows ;1. $17^{\circ}C$ cold water alone and cold water plus 8-hour short day treatments significantly accelerated the flower bud differentiation of Nyoho cultivar to 11 and 15 days, respectively, comparing to common soil raising seedling.2. The date of flower bud differentiation of Nyoho cultivar as influenced by cold water treatment the 17th, the 13th and the 10th of September, respectively, when the seedlings were treated on the 10th of September and on the 25th and the 10th of August in 1991. In 1992, data showed that the flower bud differentiation dates were the 4th and the 2nd of September and the 29th of August when cold water treatment was done on the 10th of August and on the 25th and the 10th of July.3. The first harvest date when Nyoho cultivar was treated by cold water for 30days from Jul. 25 was Nov. 10, this implying that the harvesting day could advanced to 19 days comparing to that by the common soil raising seedling method. The resulting yield was recorded to 21.94 ton per hectare.4. Regardless of the starting date of the treatment, $13^{\circ}C$ low night temperature plus 8-plus short day treatments for 20 days required 17 days to differentiate the flower bud of Nyoho cultivar. Harvesting day could be advanced to 59 days comparing to that by the common raising seedling method when the seedling was treated on July 25, this resulting in increasing the total yield obtained by April 14 of following year to 8.25 ton per hectare.5. When the seedlings of both Nyoho and Hokowase cultivars were raised under the condition of abandoned mine, flowering and harvest date were earlier by the treatment for 20 days than that for 30 days or 40 days. The highest yiesd obtained was recorded in Nyoho cultivar or 1.88 ton per hectare.

• Korean Journal of Agricultural Science
• /
• v.35 no.1
• /
• pp.101-118
• /
• 2008

This paper reviews the present situation of Triticale cultivation and examines the potentiality of contribution to livestock as well as poultry sector in Bangladesh Agriculture. Triticale is a human-made cross between rye and durum wheat that has the ability to produce quality green fodder, and then re-grow after first and second cutting to produce grain. In Bangladesh, it is a non-traditional cereal that grows well during the cool and dry Rabi season (November-March) when fodder and feed scarcity is a major limiting factor for ruminant livestock. In Bangladesh Triticale was started to grow in the late Ninety's. The scientists of Bangladesh Agricultural Research Institute (BARI) were first introduced triticale in Bangladesh. Still now the situation of Triticale is grown as fooder and feed in Bangladesh within the scientists under trial. High quality grass fodder was obtained by cutting green triticale plants twice, at 35 and 50 days after seeding, while later the ratooning tillers produced grain to a yield of 1.1-2.4 t/ha of grain for poultry feed or human food. Triticale straw was twice as nutritious as rice or wheat straw and its grain contained more protein than other cereals. Researchers and farmers have also successfully made triticale hay and silage from a mixture of triticale green cuttings, rice straw and molasses. A feeding trial at Bangladesh Livestock Research Institute(BLRI), Savar station showed a large(46%) increase in cow live weight gain and a 36% increase in milk yield (but no change in milk quality or dry matter intake) in cows fed triticale silage compared with those fed rice straw over a period of nine weeks. In another feeding trial, it was found that triticale grain was a good replacement for wheat in the feed blend for chickens in Bangladesh. So it will be a good chance to alive our livestock as well as poultry sector if triticale enters to our existing cropping system as fodder cum grain. The challenge in Bangladesh is to identify fodder technologies that match existing small-scale farmer cropping patterns without needing major inputs or increasing risks. Preliminary field experiments revealed that triticale is a crop with good potential to produce quality fodder and grain for small scale farmers in Bangladesh.