• 한국해양학회지
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• v.30 no.4
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• pp.279-287
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• 1995

The vertical profiles of natural ²¹⁰Pb, ²¹⁰Po and ²³⁴Th activities were measured for the upper 100 m of water column at three stations in the middle region of the Korean East Sea during May 1992. And the distribution of these radionuclides was discussed associated with the formation of warm eddy or water mass. The main thermocline was maintained between the depth of 50 and 100 m at the southern station (Sta. A1), and between the depth of 10 to 50 m at the coastal station of Sockcho (Sta. B10). Contrastingly, a main thermocline at Sta. A10, which locates near the center of warm eddy, was observed below 230 m depth. Between 50 and 220 m depth of Sta. A10 is there a relatively homogeneous water mass of 10.1${\pm}$0.5$^{\circ}C$, which is significantly higher in temperature and lower in nutrient than the other two stations. It seems to be due to sinking of the warm surface water in which nutrients were completely consumed. Both ²¹⁰Pb and ²¹⁰Po show the highest concentration at Sta. A1 and the lowest at Sta. B10 among the three stations. Also, the ²¹⁰Pb activity is generally higher in the upper layer than in the lower layer, while ²¹⁰Po activity represents the reversed pattern at all three stations. At Sta. A1 and Sta. B10, the activities of ²¹⁰Po relative to its parent ²¹⁰Pb were deficient in the water column above the main thermocline, but were excess below the thermocline. However, the station near the center of warm eddy(Sta. A10), shows no excess of ²¹⁰Po in the depths below 50 m, although its defficiency is found in the upper layer like the other stations. At Sta. A1 and b10. ²³⁴Th activities are slightly lower in the surface mixed layer than in the deeper region However, at Sta. A10, ²³⁴Th activity in the upper 30 m is higher than below 50 m or in the same depth of the other stations, probably because of the high concentration of particulate matter. The residence time of ²¹⁰Po in the surface mixed layer at Sta. A10 is 0.4 year, much shorter than at the other two stations(about one year). Above 100 m depth, the residence times of ²³⁴Th range from 18 to 30 other two stations(about on year). Above 100 m depth, the residence times of ²³⁴Th range from 18 to 30 days at all stations, without significant regional variation. The percentages of recycled ²¹⁰Po within the thermocline are 39% and 92% at Sta. A1 and Sta. B10, respectively. Much higher value at Sta. B10 may be due to a thin thickness of the mixed layer as well as the slower recycling rate of ²¹⁰Po in the main thermocline.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.4
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• pp.343-354
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• 2010

The present study was conducted to examine the fermentation characteristics and effective degradability (ED) in the rumen, and whole tract digestibility of whole crop silage based TMR in comparison with conventional separate feeding of concentrate and roughage. Three ruminally fistulated non-lactating Holstein cattle were used in a 3 $\times$ 3 Latin square design. The cattle were fed 8kg of whole crop barley silage based TMR (BS-TMR) or 8kg (DM basis) of whole crop rye silage based TMR (RS-TMR) twice (08:00 and 18:00) daily in an equal amount. The cattle were also fed concentrate (5.6kg) and rice straw (1.4kg) seperately (DM basis, Control) twice daily in an equal amount. The both silages were included in TMR at 20% level (as fed basis). pH in the rumen fluid was not influenced by the diets but was slightly higher from TMR than from control. No difference was found in ammonia-N concentration between diets. Total VFA concentration was relatively increased in the cattle fed RS-TMR to the other diets up to 6h post feeding. The proportion of acetate was increased in the TMR feeding at right before feeding (0 h, p<0.005) and 9 h (p<0.048) post feeding compared with control. Propionate proportion was increased (p<0.046) in both TMRs while butyrate proportion was increased (p<0.029) at 1h post feeding compared to other diets. Effective degradability (ED) of DM and CP of RS-TMR was relatively increased to other diets, and EDNDF of both TMRs was higher than that of control diet due to the increased parameters b (p<0.039) and c (p<0.006) in TMR treatments. Whole track digestibility of most components in the TMRs was slightly increased compared to that in control diet, and RS-TMR had a tendency to be increased whole track digestibility except for NDF compared to BS-TMR. Based on the results observed from the present study, nutrient availability of whole crop silage based TMR looked slightly better than conventional separate feeding of concentrate and rice straw, mainly due to the improved stabilization of fermentation in the rumen and increased NDF digestibility of whole crop silage in TMR.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.1
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• pp.19-28
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• 2020

This study was conducted to compare the agronomic characteristics and productivity according to the species and varieties of winter forage crops in reclaimed land. Winter forage crops used in this study were developed in National Institute of Crop Science, RDA. Oats ('Samhan', 'Jopung', 'Taehan', 'Dakyung' and 'Hi-early'), forage barley ('Yeongyang', 'Yuyeon', 'Yujin', 'Dacheng' and 'Yeonho'), rye ('Gogu', 'Jogreen' and 'Daegokgreen') and triticale ('Shinyoung', 'Saeyoung', 'Choyoung', 'Sinseong', 'Minpung' and 'Gwangyoung') were planted in the reclaimed land of Sihwa district in Hwaseong, Gyeonggi-do in the autumn of 2018 and cultivated using each standard cultivation method, and harvested in May 2019(oat and rye: 8 May, barley and triticale: 20 May.) The emergency rate was the lowest in rye (84.4%), and forage barley, oat and triticale were in similar levels (92.8 to 98.8%). Triticale was the lowest (416 tiller/㎡) and oat was the highest (603 tiller/㎡) in tiller number. Rye was the earliest in the heading date (April 21), triticale was April 26, and oat and forage barley were in early May (May 2 and May 5). The plant height was the highest in rye (95.6 cm), and triticale and forage barley was similar (76.3 and 68.3cm) and oat was the lowest (54.2 cm). Dry matter(DM) content of rye was the highest in the average of 46.04% and the others were similar at 35.09~37.54%. Productivity was different among species and varieties, with the highest dry matter yield of forage barley (4,344 kg/ha), oat was similar to barley, and rye and triticale were lowest. 'Dakyoung' and 'Hi-early' were higher in DM yield (4,283 and 5,490 kg/ha), and forage barley were higher in 'Yeonho', 'Yujin' and 'Dacheng' varieties (4,888, 5,433 and 5,582 kg/ha). Crude protein content of oat (6.58%) tended to be the highest, and TDN(total digectible nutrient) content (63.61%) was higher than other varieties. In the RFV(relative feed value), oats averaged 119, while the other three species averaged 92~105. The weight of 1,000 grain was the highest in triticale (43.03 g) and the lowest in rye (31.61 g). In the evaluation of germination rate according to the salt concentration (salinity), the germination rate was maintained at about 80% from 0.2 to 0.4% salinity. The correlation coefficient between germination and salt concentration was high in oat and barley (-0.91 and -0.92) and lowest in rye (-0.66). In conclusion, forage barley and oats showed good productivity in reclaimed land. Adaptability is also different among varieties of forage crops. When growing forage crops in reclaimed land, the selection of highly adaptable species and varieties was recommended.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.3
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• pp.232-241
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• 1984

For the purpose of investigating the effect of chemical composition of nitrogenous fertilizers such as urea, ammonium sulfate, ammonium phosphate(dibasic) and aqua-ammonia on growth, yield, efficiency and chemical properties of paddy soil this study was carried out at the same nitrogen concentration through field experiment. The results obtained was summarized as follows. 1. Nitrogenous fertilizers had an effect on plant height at heading stage, plant weight at harvest and No. of spikelet per panicle of rice plants in decreasing order: Ammonium sulfate > Diammonium phosphate > Urea > Ammonia water. But they didn't effect on culm length, spike length, dry matter weight, No. of grain per spike, ripening ratio and weight of 1000 grains of rice plants. 2. The absorbed amount of nitrogen and that of sulfur and nitrogen availability were highest in ammonium sulfate application and lowest in ammonia water application and these were positively correlated with yield. 3. The influence of nitrogenous fertilizers on nitrogen and sulfur efficiency and translocation efficiency was insignificant but that of ammonium sulfate on nitrogen efficiency was higher than that of the others. 4. The effect of nitrogenous fertilizers on a basic chemical properties of paddy soil experimented such as pH, C.E.C, exchangeable cation and organic matter was insignificant. But the sulfur content of ammonium sulfate application and phosphorous content of diammonium phosphate application were higher than that of the others.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.513-521
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• 2009

The primary goal of this research was to develop an optimized analytical procedure for soil analysis based on ion-selective microelectrodes for agricultural purposes, which can perform on-site measurement of various ions in soil easily and rapidly. For the simple and rapid on-site diagnosis, an analysis of soil chemicals was performed employing a multicomponent-in-situ-extractant and an evaluation of ionselective microelectrodes were conducted through the regressive correlation method with a standard analytical approach widely employed in this area. Examination of sensor responses between various soil nutrient extractants revealed that 0.01M HCl and 1M LiCl provided the most ideal Nernstian response. However, 1M LiCl deteriorated the selective response for analytes due to high concentration (1M) of lithium cation. Thus, employing either 0.1M HCl as an extractant followed by 10 times dilution, or 0.01M HCl as an extractant without further dilution was chosen as the optimal extractant composition. A study of regressive correlation between results from ion-selective microelectrodes and those from the standard analytical procedure showed that analyses of $K^+$, $Na^+$, $Ca^{2+}$, and $NO_3{^-}$ showed the excellent consistency between two methods. However, the response for $NH_4{^+}$ suffered the severe interference from $K^+$. In addition, the selectivity for $Mg^{2+}$ over $Ca^{2+}$ was not sufficient enough since available ionophores developed so far do not provide such a high selectivity for $Mg^{2+}$. Therefore, as an agricultural on-site diagnostic instrument, the device in development requires further research on $NH_4{^+}$ analysis in the soil sample, development of $Mg^{2+}$-selective ionophore, and more detailed study focused on potassium, one of the most important plant nutrients.

• Korean Journal of Poultry Science
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• v.40 no.1
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• pp.57-65
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• 2013

This study was conducted to evaluate the effect of dietary Weissella koreensis (Wk), a prominent kimchi lactic acid bacteria supplementation on growth performance, nutrients utilization, gut microbiota and meat characteristics in broiler chicken. Both live and killed Wk was compared to know which could be more efficacious as a feed probiotics. Three Wk supplemented groups and no Wk supplemented group were designated according to supplementation levels and cell status. Those were; Control (no Wk), 0.1 % live Wk (LWk 0.1), 0.5% live Wk (LWk 0.5) and 0.5% killed Wk (KWk 0.5). Body weight gain and feed conversion efficiency were improved (P<0.05) by dietary LWk supplementation. KWk did not exert any benefit on growth performance. Crude protein utilizability of KWk supplemented diet was lower (P<0.05) than that of other diets. However, there were no differences among treatments in other nutrients utilization. Serum IgG concentration and relative weight of bursa of Fabricius was highest (P<0.05) in broiler chicken fed KWk 0.5 diet. Cecal anaerobic lactic acid bacteria count of LWk groups were higher (P<0.05) than those of control and KWk 0.5 groups. Dietary Wk supplementation failed to lower the count of cecal and fecal E. coli. There was no effect of dietary Wk on TBARS values and fatty acids profile of broiler leg meat. However, the dietary supplementation of Wk exerted characteristic difference on electronic nose flavor of broiler meat. This study showed that dietary supplementation of LWk was able to improve body weight gain, feed conversion efficiency and cecal lactic acid bacterial count in broiler chicken. Further, the result of this study implemented that a live kimchi lactic acid bacteria, LWk, but not killed Wk, could be used as a probiotic feed supplement for broiler.

• The Korean Journal of Malacology
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• v.32 no.3
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• pp.231-240
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• 2016

Techniques were developed for holding and conditioning of Pacific oysters, Crassostrea gigas, in a closed recirculating system. Experimental adults were used 500 oysters ( x two system, total 1,000 oysters) which were collected in $20^{th}$ March 2016 from long-line aquaculture farm at the south coast of Korea. During conditioning periods concentrated live microalgae as Isochrysis sp. $15{\times}10^7cells/mL$, Tetraselmis sp. $2{\times}10^7cells/mL$ and Pheaodactylum sp. $18{\times}10^7cells/mL$ were added 5 L every day, respectively which micro algae were functioned as diets and biological filter. Over all experimental periods total water exchange rate was 21.3% (daily 0.5%). Over 42 days conditioning, female and male oysters were maturated 90.9% and 94.4%, respectively. Survival rate was 98.7%. Mean shell hight (8.3 mm), total wet weight (19.2 g), meat wet weight (5.0 g) and shell wet weight (13.6 g) were significantly increased (P < 0.05). Water quality parameters including the water temperature ($22.1{\pm}0.4^{\circ}C$), salinity ($24.9{\pm}04$), dissolved oxygen (5.1-7.9 mg/L) and pH ($7.93{\pm}0.15$) were kept stable. Concentration of dissolved inorganic nutrient as ammonia (1.96-0.35 mg/L), nitrite (0.03-0.16 mg/L), nitrate (1.34-0.47 mg/L), DIP (0.42-0.03 mg/L) and silicate (3.83-0.00 mg/L) were significantly decreased throughout experiment except nitrite which was increased (P < 0.05), but nitrogenous components stayed below toxic levels (ammonia 0.0-5.5 mg/L, nitrite 0.0-460.0 mg/L) which indicated that closed recirculation system with microalgae based bio-filter could supply sufficiently environment condition to holding and conditioning of oyster.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.392-396
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• 1989

Methylobacterium organophilum, a facultative methylotroph was cultivated on a methanol as a sole carbon and energy source. The cell growth was affected by the various components of minimal synthetic medium and the medium composition was optimized with 0.5% (v/v) methanol at pH 6.8 and at 3$0^{\circ}C$. The maximum specific growth rate of M. organophilum was achieved to 0.26 hr$^{-1}$ in the optimized medium which has following composition: Methanol, 0.5% (v/v):(NH$_4$)$_2$SO$_4$, 1.0g/l:KH$_2$PO$_4$, 2.13g/l:KH$_2$PO$_4$, 1.305g/ι:MgSO$_4$.7$H_2O$. 45g/l and trace elements (CaCl$_2$.2$H_2O$, 3.3mg:FeSO$_4$.7$H_2O$, 1.3mg:MnSO$_4$.4$H_2O$, 130$\mu\textrm{g}$:ZnSO$_4$.5$H_2O$, 40$\mu\textrm{g}$:Na$_2$MoO$_4$.2$H_2O$, 40$\mu\textrm{g}$:CoCl$_2$.6$H_2O$, 40$\mu\textrm{g}$:H$_3$BO$_3$, 30$\mu\textrm{g}$ per liter). By the limitation of nitrogen and deficiency of Mn$^{+2}$ or Fe$^{+2}$, the cell growth was significantly repressed. Methanol greatly repressed the cell growth and the complete inhibition was observed at concentration above 4% (v/v). In order to overcome the methanol inhibition and to prevent the methanol limitation, intermittent feeding of methanol was conducted by a D.O.-stat technique. PHB production by M. organophilum was stimulated by deficiency of nutrients such as NH$_{4}^{+}$, SO$_{4}^{-2}$, $Mg^{+2}$, $K^{+}$, or PO$_{4}^{-3}$ in the medium. The maximum PHB content was obtained as 58% of dry cell weight under deficiency of potassium ion in the optimized synthetic medium.

• Journal of Bio-Environment Control
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• v.8 no.2
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• pp.75-82
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• 1999

This study was carried out to examine the effect of day/nignt temperatures during seedling culture on the vegetative and reproductive growth of Lycopersicum esculentum ‘Seokwang’. The study was consisted of two culture stages, plug seedling production in the growth chamber and hydroponic culture of the plant in a glasshouse. Experiments were replicated over time. The germinated seedlings were raised for 33 days (experiment 1) and 35 days (experiment 2) in 4 growth chambers, each with day/night temperatures of either $25^{\circ}C$/$25^{\circ}C$, 16$^{\circ}C$/16$^{\circ}C$, 16$^{\circ}C$/$25^{\circ}C$ or $25^{\circ}C$/16$^{\circ}C$. Cool-white fluorescent lamps provided 140$\mu$mol.m$^{-2}$ .s$^{-1}$ light for 12h each day. In the second experiment, all chambers were supplied with 1000$\mu$mol.mol$^{-1}$ CO$_{2}$ during the photoperiod and had an air velocity of 0.3m.s$^{-1}$ and relative humidity of 80%. Plug seedlings raised were transplanted to rockwool slabs in a glasshouse and were grown hydroponically using the same nutrient solutions used for seedling culture for 37 days (experiment 1) and 35 days (experiment 2). Plant height was affected more by mean daily temperature than by interaction of day and night temperatures. Plant height was the highest in 16/16$^{\circ}C$ treatment. Leaf count was not affected by day and night temperatures, and the chlorophyll concentration was the highest in 16/$25^{\circ}C$ treatment. Fresh and dry weights of stem tended to be greater in treatments of constant day and night temperature. The number of node on which first and second flower clusters were set was significantly higher in 25/$25^{\circ}C$ treatment than in the other treatments. Days to flower of the first flower on the first flower cluster were the greatest in 25/$25^{\circ}C$ and the least in 16/$25^{\circ}C$ treatment. Vegetative and reproductive growth, such as height, fresh and dry weights, days to flower, and nodes of the 1st and 2nd flower cluster set were affected by day/night temperatures.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.3
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• pp.197-208
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• 2007

This study was carried out to investigate effects of increasing moisture content with or without supplementing inoculant (Lactobacillus plantarum) in TMR (total mixed ration) on its feed value. In case of exposing TMR to air, the lower the moisture level of TMR was, the less its apparent condition was changed. The time of spreading of molds tended to be faster in TMR with the higher moisture level. And also the odor was influenced by moisture content and inoculant supplement that is, sour odor was smelled from 24 hour after exposing TMR containing 35% and 50% moisture to air, but TMR supplemented with inoculant had sweet odor. The inner temperature of TMR containing 35% and 50% moisture without inoculant tended to increase continually after the lapse of 6 hours when the TMR was exposed to air. The inner temperature of TMR containing 35% moisture with inoculant tended to increase dramatically after the lapse of 48 hours when exposed to air, but that of TMR containing 50% moisture with inoculant tended to increase after 6 hours. The pH of TMR containing 15% was consistent regardless of exposing time to air, but that of TMR containing 35% and 50% moisture considerably increased after 12 and 24 hours, respectively. The concentration of $NH_3-N$ of TMR supplemented with inoculant was increased from 6 hours after exposure to air, while that or TMR without inoculant increased from 12 hours. Nutrient content or TMR tended to be increased with the increase of exposing time to air and storage time under sealed condition.