• Journal of Korean Society of Forest Science
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• v.54 no.1
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• pp.49-59
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• 1981

In order to elucidate the process of plant succession of the Japanese red pine forests caused by pine gall midge, Thecodoplosis japonensis, in the area of Chungbuk and Kyongbuk, 12 study plots, 4 plots from each three districts, were set up. Districts A (Cheongwon)not attacked by this insect, as the check, District B(Gumi) in which the insect outbreak occured 5 years ago, and District C(Yeongdong)in which the insect outbreak occured 10 years ago, were sampled. The surveyed were some environmental factors, the number of woody plants, relative density, relative dominance values, species composition of plots by layer(upper, middle and ground), importance values, species diversity, similarity and dissimilarity index, etc. The results obtained are summarized as follows: The accumulation of litter on the ground was increased with the lengthening the insect damage duration. Through the crown opening and litter accumulation, the light intensity, temperature condition and soil moisture and nutrient content might be altered. According to the changes of species composition were forced. In general, the Genus Quercus, as a compensation species, has sprung up. The relative importance values for Q.aliena, Q.serrata, and Q.variabilis were significantly increased in the insect infested forests. 2. the stand structure and species composition of the insect attacked forest about 5 years later after the outbreak become complex and diverse. However, since this time, the simplicity of these regards become restored up to 10 years after the outbreak. 3. As the synthetic analysis of plant succession process, the relative values calculated from the relative density and the relative dominance values shown the dominant status of Genus Quercus in the heavily damaged forests. In addition, Genus Rhododendron and Genus Lespedeza with higher frequency become the ground vegetation components. They were gradually increased along the time elapsing after the insect out-break. 4. The differences in connection with the soil moisture contents, the organic matter contents which might give some influences to the vegetation change were hardly recognizable statistically among the studied plots by three district groups. We estimated that the annual mean precipitation and the annual mean temperature did not operated any meaningful effects on the vegetation alteration among plots between districts.

• The Korean Journal of Malacology
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• v.20 no.2
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• pp.111-120
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• 2004

We investigated the reproductive cycle of Corbicula japonica with its gonadal development by histological observations, and the seasonal changes in biochemical mass and foot muscle of the adductor muscle, visceral mass and foot muscle of the clam by biochemical analysis, from January to December, 2003. The reproductive cycle of this species can be classified into five successive stages: early active stage (February to April), late active stage (April to July), ripe stage (June to August), partially spawned stage (July to September) and spent/inactive stage (September to March). According to ANOVA test, there were significant differences (p < 0.05) in total protein, total lipid and glycogen contents among months for all of the visceral mass, adductor muscle and foot muscle. Total protein content was highest in adductor muscle, while lowest in visceral mass. There was no correlation in total protein content between visceral mass and adductor muscle (p = 0.208). However, strong positive correlation was found between adductor muscle and foot muscle (r = 0.769, p < 0.001). In visceral mass, total lipid content was the highest; it was 2 or 3-fold higher than in adductor muscle or foot muscle. The monthly change was also most dynamic in visceral mass. It decreased from January to March (early active stage), and reached maximum in April (late active stage). From May to August (ripe and partially spawned stage), it dradually decreased and then increased again until October (spent/inactive stage). Multiple comparisons showed that total lipid content in visceral mass between all of the adjacent two months was significaltly different (p < 0.05). There were strong negative correlations in total lipid content between visceral mass and adductor muscle (r = 0.687, p < 0.001), and between visceral mass and foot muscle (r = 0.473, p = 0.008). Changes of glycogen content were more or less similar to the changes of lipid contents in visceral mass, adductor muscle and foot muscle, except for April. In April, glycogen content in visceral mass was over four times higher than that in adductor muscle or foot muscle. There was a positive correlation in glycogen content between adductor muscle and foot muscle (r = 0.686, p < 0.001). Especially, total lipid content showed a negative correlation between the adductor muscle and visceral mass. Therefore, these results indicate that the nutrient content of the adductor muscle, visceral muscle and foot muscle changed in response to gonadal energy needs.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.134-144
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• 2009

Paleoproductivity changes in the central part of the Bering Sea since the last glacial period were reconstructed by analyzing opal and total organic carbon (TOC) content and their mass accumulation rate (MAR) in sediment core PC23A. Ages of the sediment were determined by both AMS $^{14}C$ dates using planktonic foraminifera and Last Appearance Datum of radiolaria (L. nipponica sakaii). The core-bottom age was calculated to reach back to 61,000 yr BP. and some of core-top was missing. Opal and TOC contents during the last glacial period varied in a range of 1-10% and 0.2-1.0%, and their average values are 5% and 0.7%, respectively. In contrast, during the last deglaciation, opal and TOC contents varied from 5 to 22% and from 0.8 to 1.2%, respectively, with increasing average values of 8% and 1.0%. Opal and TOC MAR were low ($1gcm^{-2}kyr^{-1}$, $0.2gcm^{-2}kyr^{-1}$) during the last glacial period, but they increased (>5 and >$1gcm^{-2}kyr^{-1}$) during the last deglaciation. High diatom productivity during the last deglaciation was most likely attributed to the elevated nutrient supply to the sea surface resulting from increased melt water input from the nearby land and enhanced Alaskan Stream injection from the south under the restricted sea-ice and warm condition during the rising sea level. On the contrary, low productivity during the last glacial period was mainly due to decreased Alaskan Stream injection during the low sea-level condition as well as to extensive development of sea ice under low-temperature seawater and cold environment.

• Journal of Aquaculture
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• v.17 no.2
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• pp.144-150
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• 2004

This experiment was conducted to evaluate the parameters such as nutrient requirements, POY, AnV, Totox, VBN, total plate count, dietary fatty acids and amino acids composition, that are not included in the registered standard composition items required by the Ministry of Agriculture and Forestry, of a moist pellet (MP), three domestic extruded pellets (DEP-1, DEP-2, DEP-3), and two foreign extruded pellets (FEP-1, FEP-2) that are utilized by domestic flounder farms at present. The crude protein was added in excess of the dietary protein requirement in 6 kinds of feeds. When considering the proper PH ratio, it is obvious that protein was added in excess, especially in MP and FEP-2. Crude fat was also added in excess, especially in FEP-1. MP contained a higher dietary phosphorus content than formulated feeds, surpassing the dietary phosphorus requirement and greatly increasing the possibility for causing water pollution. The oxidation of fatty acid and decomposition of protein in MP were higher than in formulated feeds, and may also cause problems on fish farms. Also, it is difficult to store and manage MP, Among the fatty acids, EPA and DHA contents in MP were higher than those in formulated feeds. It is necessary to conduct further studies of EPA and DHA contents in formulated feeds. Lysine content in MP and FEP-2 could meet the dietary lysine requirement of flounder, however, the possibility of insufficient lysine content in the other formulated feeds was high and we considered that extra supplementation was necessary. Therefore, it is necessary to set up quality control standards according to fish species and sizes while considering the specific character of aquatic formulated feeds to restore the confidence of feed companies and aquaculturists to these feeds. This may be an opportunity to make an earlier change from MP to formulated feeds.

• Journal of Aquaculture
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• v.7 no.1
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• pp.63-76
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• 1994

The effects of different dietary lipids on growth, body chemical composition, and nutrient partition of the Korean rockfish (43 g of initial mean weight) were studied. Fish were fed three experimental diets containing 1) $4.5\%$ squid liver oil, 2) $1\%$ squid liver oil and $3.5\%$ beef tallow, and 3) $1\%$ squid liver oil and $3.5\%$ soybean oil. Growth and feed efficiency were detarmined during a 19-week feeding period at water temperature of $15.5^{\circ}C$, and at the end of which body chemical compositions were analyzed. Remained fish were fasted for 45 days, and four fish were taken at 6, 12 and 24 hours, and 3, 15 and 45 days after the fasting to determine tissue compositions and hematological changes. Growth, feed efficiency, protein and lipid retention efficiency, hepatosomatic index(HSI), viscerosomatic index (VSI), and chemical composition of whole body and dorsal muscle were not affected by the different dietary lipids. Liver moisture content of fish fed squid liver oil diet was higher than that of fish fed beef tallow or soybean oil diet. Liver lipid content of fish fed beef tallow diet was higher than that of fish fed the other diets. Fatty acid composition of dorsal muscle and liver were affected by the different dietary lipids ; high levels of 20 : 5n-3 and 22 : 6n-3 from fish fed the diet containing squid liver oil, 18 : 1 from fish fed the diet containing beef tallow, and high 18 : 2n-6 and 18 : 3n-3 from fish fed the diet containing soybean oil were observed. Both HSI and VSI of fish fed three diets decreased with time after the begining of starvation. Liver glycogen did not change during the first 15 days of starvation and decreased thereafter, and that was not affected by the different dietary lipids. Lipid and protein contents in the dorsal muscle of fish decreased up to 15 days of starvation and remained unchanged thereafter, these were not different from each other. Glucose, free fatty acid, triglyceride and phospholipid concentrations in Fish serum were varied for the first 15 days of starvation, after that the concentrations of fish serum remained relatively stable in all the treatment groups with prolonged starvation. The results indicate that Korean rockfish can utilize fish oil, animal fat or vegetable oil equally as energy source when n-3HUF A is adquate.

• Journal of Animal Science and Technology
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• v.49 no.6
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• pp.745-752
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• 2007

A total of thirty sows(Landrace×Yorkshire) were used to determine the effects of plant protein source containing multienzyme on performance, nutrients digestibility and milk characteristics. A feeding trial was conducted for 21 days from parturition to weaning. Experimental diets were supplied for 1 week before the parturition day and throughout the experimental period. Dietary treatments included: 1) Control(CON; basal diet), 2) CGLT(included corn gluten) and 3) FSPM(included fermented soy protein containing multienzyme). Through the entire experimental period, backfat loss and return-to-estrus intervals were not affected by the treatments(P>0.05). Nitrogen digestibility was increased significantly(P<0.05) in FSPM treatment compared to CON treatment. Blood urea nitrogen(BUN) concentration was increased significantly (P<0.05) in FSPM treatment compared to CON treatment. At the initial  period, total protein content of milk was higher significantly(P<0.05) in FSPM treatment compared to CGLT treatment and at the final period, total fat content of milk was higher significantly(P<0.05) in FM treatment compared to CON treatment. Rectal temperature showed similar tendency of change among treatments. The final piglet body weight, weight gain and ADG were higher significantly in FSPM treatment compared to CON treatment. On diarrhea rate in piglet, just one piglet occurred in CGLT treatement. In conclusion, 2.5% dietary plant protein source containing multienzyme suppelmentation improved N digestibility, BUN concentration, fat and protein contents in milk and weight gain in piglet.

• Journal of Animal Science and Technology
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• v.49 no.6
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• pp.773-782
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• 2007

A total of thirty sows(Landrace×Yorkshire) were used to determine the effects of plant protein source containing multienzyme on performance, nutrients digestibility and milk characteristics. A feeding trial was conducted for 21 days from parturition to weaning. Experimental diets were supplied for 1 week before the parturition day and throughout the experimental period. Dietary treatments included: 1) Control(CON; basal diet), 2) CGLT(included corn gluten) and 3) FSPM(included fermented soy protein containing multienzyme). Through the entire experimental period, backfat loss and return-to-estrus intervals were not affected by the treatments(P>0.05). Nitrogen digestibility was increased significantly(P<0.05) in FSPM treatment compared to CON treatment. Blood urea nitrogen(BUN) concentration was increased significantly (P<0.05) in FSPM treatment compared to CON treatment. At the initial  period, total protein content of milk was higher significantly(P<0.05) in FSPM treatment compared to CGLT treatment and at the final period, total fat content of milk was higher significantly(P<0.05) in FM treatment compared to CON treatment. Rectal temperature showed similar tendency of change among treatments. The final piglet body weight, weight gain and ADG were higher significantly in FSPM treatment compared to CON treatment. On diarrhea rate in piglet, just one piglet occurred in CGLT treatement. In conclusion, 2.5% dietary plant protein source containing multienzyme suppelmentation improved N digestibility, BUN concentration, fat and protein contents in milk and weight gain in piglet.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.706-713
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• 2013

With pot-grown 4-year-old 'Fuyu' persimmon trees, this study evaluated the effect of different nitrogen (N) rates during summer on fruit characteristics, changes of leaf nutrients after harvest, reserve accumulation, and early growth the following year. A total of 0, 36 g N in June, and 72 g N in June and July was fertigated to each tree using urea solution. All the fruits were harvested on Nov. 3. Although not significant, fruits were larger for the 36 g and 72 g N than the 0 g N. Fruits for the 0 g N, having lower N concentration, were softer and had a better coloration and higher soluble solids, indicating that they matured earlier. SPAD value on Nov. 3 was 19.2 for the 0 g N and 54.9 for the 72 g N, and then the values linearly decreased in all the treatments by Nov. 14, exhibiting rapid leaf senescence. Specific leaf weight, being the lowest for the 0 g N, also gradually decreased during this period. Increasing N level significantly increased cross-sectional area of the trunk. Leaf N concentration on Nov. 3 was 0.87% for the 0 g N, whereas it was 1.18 and 1.52% for the 36 g and 72 g N, respectively. The N fertigation tended to increase leaf concentrations of soluble sugars, starch, and amino acids. Contents of N, P, K, soluble sugars, starch, and amino acids per unit leaf area gradually decreased in all the treatments during the 11 days after harvest, and the extent of the decrease was the lowest for the 0 g N. On the other hand, those of Ca, Mg, and protein did not consistently change during this period. The N fertigation resulted in higher concentrations of N in dormant shoots on Nov. 14, and although not great, it also increased soluble sugars, starch, amino acids, and protein. Clear differences were found in number of flower buds per one-year-old branch and total shoot length per tree the following year. The 72 g N trees had 5.6-fold more flower buds and 1.9-fold more shoot length, compared with those of 0 g N trees. However, it was noted that tree growth the following year was not significantly different between the 36 g and 72 g N the previous year. It was concluded that N rate during summer should be adjusted with considering the changes of fruit maturation, mobilization of leaf nutrients, and reserve accumulation.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.220-230
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• 1992

Soil temperature is one of the important environmental factors which control all the physical, chemical and biological processes in soil including germination and root growth of plants and other organisms living in the soil ecosystem. Soil water and nutrient availability and mobility are temperature dependent. Soil temperature change is depended primarily upon energy exchange in soil surface, meteorological variance and physical properties of the soils which are closely related to heat transfer mechanism. In this study physical properties including bulk density, soil texture and organic matter content were measured and thermal diffusivity on the soils was calculated. Soil samples from the 66 meteorological stations under the Korea Meteorology were collected and the physical parameters were measured. To obtain relationship between thermal diffusivity and soil water content a heat probe thermal diffusivity measurement apparatus was designed and used in this experiment. According to the survey on soil physicsal properties on the 66 meteorological stations, the 52% of the surface soil texture were sandy loam and laomy sand or sand, 38% were loam and silty loam, and 10% were clay loam and silty clay loam. The bulk density which was closely related with thermal properties showed average of $1.41g/cm^3$ for sandy soils, $1.33g/cm^3$ for loam and silty loam soils, and $1.21g/cm^3$ for clay loam and silty clay loam soils. The apparent thermal diffusivity of the upper layer from 0 to 30cm ranged from 1.16 to $8.40{\times}10^{-3}cm^3/sec$ with average of $3.53{\times}10^{-3}cm^3/sec$. The apparent thermal diffusivities of the Jeju soils of which organic matter contents were high and the bulk densities were low were near $2{\times}10^{-3}cm^3/sec$. The thermal diffusivity of snow measured in Chuncheon ranged from 0.822 to $2.237{\times}10^{-3}cm^3/sec$. The damping depth calculated from the thermal diffusivity ranged from 5.92 to 13.65cm for daily basis and 124 to 342cm for yearly basis. The significant regression equation to estimate thermal diffusivity with bulk density and soil water content was obtained by the heat probe in laboratory.