• Title/Summary/Keyword: Water layer

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Phytoplankton Response to Short-term Environmental Changes in the Vicinity of a Fish Cage Farm of Tongyeong Obi in Summer (통영 오비도 어류양식장 주변에서 하계 수계 내 단주기 환경요인의 변화에 따른 미세조류 반응)

  • Lee, Minji;Baek, Seung Ho
    • Journal of Marine Life Science
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    • v.2 no.2
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    • pp.62-69
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    • 2017
  • In order to assess the potential environmental factors in the vicinity of a fish cage farm, we investigated the biotic and abiotic factors during a short-term period in summer 2016 in two inner stations of Tongyeong Obi. High water temperature on August 10th was apparent among the full depth of up to 29℃, which might have been related to the abnormally high temperatures of large amounts of the Changjiang River discharge along the Tongyeong coast. The concentration of nitrate+nitrite, ammonium, phosphate, and silicate ranged from 0.08 to 5.11 μM, 0.08 to 34.62 μM, 0.01 to 1.15 μM, and 1.46 to 31.79 μM, respectively. The nutrients were mainly supplied by precipitation and leaching from the bottom sediments in the fish culture farm area. It was not retained for a long duration because of the phytoplankton consumption and diffusion by water currents. The chlorophyll a concentration varied from 0.49 ㎍ l-1 to 7.39 ㎍ l-1. At that time, Chaetoceros debilis, C. pseudocurvisetus, and Pseudo-nitzschia delicatissima were rapidly proliferated and reached the level of 4.74 × 109 cells l-1. In particular, the lowest dissolved oxygen was recorded at 4.52 ㎍ l-1 at the bottom layer after bloom. Therefore, even though phytoplankton blooms in summer have frequently occurred in a fish culture farm area, the oxygen-deficient environments were not found in neither the surface nor bottom layers, which implied that the water masses might be well exchanged from the mouth of the northwest and southeast between Obi and Mireuk Island in the study area.

Estimate of Particulate Organic Carbon Export Flux Using $^{234}Th/^{238}U$ Disequilibrium in the Southwestern East Sea During Summer (동해 서남해역에서 여름철 $^{234}Th/^{238}U$ 비평형을 이용한 입자상 유기탄소 침강플럭스 추정)

  • Kim, Dong-Seon;Choi, Man-Sik;Oh, Hae-Young;Kim, Kyung Hee;Noh, Jae-Hoon
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.14 no.1
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    • pp.1-9
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    • 2009
  • Export fluxes of particulate organic carbon were estimated for the first time by using $^{234}Th/^{238}U$ disequilibrium in the southwestern East Sea during August 2007. They were calculated by multiplying POC/$^{234}Th_p$ ratios of sinking particles (larger than 0.7 ${\mu}m$) obtained from 150-200 m water depths to $^{234}Th$ fluxes that were estimated by integrating $^{234}Th/^{238}U$ disequilibrium from surface to 100 m water depth. Export fluxes ranged from 14 to 505 mg C $m^{-2}$ $day^{-1}$, with the highest value at station A2 and the lowest value at station D4. Primary production was well correlated with export flux, indicating that it was a major factor controlling export flux. Export flux in the East Sea was generally higher than those estimated in the open ocean and similar to or somewhat higher than those in the continental marginal seas. Export flux/primary production (EF/PP) ratios varied from 0.29 to 0.62, with an average of 0.43 and were somewhat higher in the basin area than in the coastal area. EF/PP ratio in the East Sea was rather similar to those estimated in the North Sea and Chukchi Sea, but much higher than those in the Labrador Sea, Barents Sea, and Gulf of Lions. Therefore, the East Sea is one of the major areas where a large amount of organic carbon produced in the euphotic zone sinks into the deep layer below 200 m water depth.

Studies on the Lipid Composition in Three Species of Shellfish (3종(種) 패류(貝類)의 지질조성(脂質組成)에 관한 연구(硏究))

  • Son, Young Ock;Ha, Bong Seuk
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.12 no.4
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    • pp.407-419
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    • 1983
  • In this study, the lipid components of three species of shellfish included oyster(Crassostrea gigas), top shell(Turbo cornutus) representing salt water shellfish and corb shell(Corbicula fluminea producta) representing flesh water shellfish were analysed and nutriontional significances were discussed. Analysed the total lipid composition, and the fatty acid and sterol composition of total lipid were determined. The lipid was fractionated into three lipid classes neutral, glyco and phospholipid by column chromatography. The fatty acid composition of each lipid class and sterols were determined by gas liquid chromatography. The lipid components of total lipid and neutral lipid were estimated by thin layer chromatography and TLC scanner. The results were as follows: Total lipid contents of shellfish were 1.8% in oyster, 0.4% in top shell and 4.0% in corb shell. The contents of total fatty acid in total lipid were 80.7, 71.2 and 73.2%; and the contents of unsaponifiable matters were 15.4, 18.1 and 23.1% respectively. Total lipids were mainly composed of triglycerides, polar lipid-pigments and sterols as major component, and hydrocarbon-esterified sterols were determined in each sample. The major fatty acids in total lipid were palmitic(37.0%), eicosapentaenoic(13.5%) and linoleic acid(11.2%) in oyster, Octadecatetraenoic(15.8%), palmitic(11.2%), oleic(8.6%) and linoleic acid(8.1%) in top shell, but palmitic(34.0%), linoleic(12.3%) and paimitoleic acid(9.8%) in corb shell. Particularly, the contents of eicosapentaenoic acid of oyster and top shell were higher than those of corb shell. Sterol composition from three species of shellfish were mainly consisted of cholesterol (42.7~64.0%), brassicasterol(15.6~24.7%) and 24-methylenecholesterol (4.7~21.9%). But sitosterol (5.3%) was detected only in oyster and 22-dehydrocholesterol(12.9%) was only in top shell. The contents of fractionated neutral lipid was commonly higher than that of polar lipid in each sample. Glycolipid and phospholipid in polar lipid showed similar in quantity. The neutral lipids were composed of triglycerides(33.0~36.7%), free sterols(25.7~31.2%), esterified sterol(12.4~23.7%) and free fatty acids(5.1~11.7%). The contents of triglycerides and free sterols were higher than those of free fatty acids and esterified sterols. The major fatty acids in neutral lipid were palmitic(28.4~26.4%) eicosapentaenoic(18.6~21.9%) and linoleic acid(9.0~5.4%) in oyster and corb shell but octadecatetraenoic(14.5%), eicosapentaenoic (13.5%) and palmitic acid(12.3%) in top shell. The major fatty acids in glycolipid were eicosenoic(10.2%), palmitic(12.1%) and linolenic acid (10.2%) in oyster, Eicosenoic(26.0%), octadecatetraenoic(14.6.%) and eicosadienoic acid(12.9%) in top shell. But eicosadienoic(21.4%) stearic(14.6%), octadecatetraenoic(8.5%) and eicosenoic acid(8.5%) in corb shell. The major fatty acids in phospholipid were myristic(16.0%), stearic(10.6%), eicosenoic(10.5%) and palmitic acid(10.3%) in oyster, Oleic(22.2%), stearic(20.7%) and linolenic acid (11.8%) in top shell but eicosapentaenoic(25.1%), myristic(8.7%) and arachidonic acid(8.3%) in corb shell.

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A Study on Marketing of Cultured Laver Products (양식해태의 유통에 관한 조사 연구)

  • 유충열
    • The Journal of Fisheries Business Administration
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    • v.4 no.1_2
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    • pp.19-57
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    • 1973
  • Laver io one of the most necessary and seasonal items in Korean food from oldtimes. Laver is lagely eaten in dried form, and its supply depends entirely upon culture weeds. The history of laver culture in Korea about sixty or seventy years is older than in Japan. Significance of laver culture is divided into two aspects, one is food supply in the nation, and the other is export to other countries. Houses engaged in laver culture are about foully thousands, and laver production in 1972 is estimated as 1, 3 bitten sheets. (1 sheet is a dried laver of 20 cm sq, in the shape of paper) Especcially meaning of layer production is the concentration of labour input, and systematic management of labour. From around 1920, the method of laver culture was introduced by Japanese Imperialism for mono culture in shallow seas, and mass products of laver is provided to Japan market, DOMESTIC MARKET Fundamental consume function calculates at below, $D_{(68_71)}$=16354 $Y^{0.471}$ $P^{-1.0662}$ where D is total layer demand, Y income variable, P price variable. It means income elasticity is 476. in the whole country, and price elasticity is 1, 07. But generally income elasticity is higher in urban area than in rural area, as shown at 1, 3 in Seoul city. Expence of laver in house expenditure is mutually correlated with another expence, See Table 12 about the relative function. See Table 14 and 16 about the relation between the gathering and the changes of price in auction, wholesale and retail price support system is for two effects, one of which is constraint of the upper price, the other is rise of the lower price. Before the system control, the equation in three year average calculated as below, $Y_{b}$ =18, 907.7455+15435.9364 t (r=0.89) where the origin t=0 is the November and the units are month. Post the system control, $Y_{p}$ =30, 047.9636+1, 631.1721t (r=0.97) therefore, this system has an effect only on the rise of lower price, Average annual margins of laver products at four market levels according to the consumer spent is below. EXPORTING MARKET Japanese demand function of laver products is, Log D=5, 289+1, 108 Log Y-1, 395 Log P (r=0.987) where D is Japanese laver demand, Y income variable, P price variable. according to which income elasticity is 1. 1 and price elasticity is 1.4. Laver production in 1970 tile highest record till then, is estimated as six billion sheets. But the recent improvement of laver culture techniques, the production of seeds and freezing storage of seeds has been stabilized. Futher new culture farms have been developed by means of break- water fences or by floating culture method. These improvements have been backed up with increased demand of laver products. Import quantity and price of Korean laver products are restrained by three organizations, that is producer, distributor and consumer. This relationship calculated by regression equation shows that import is influenced only producer organization, at the sacrifice of consumer profit. For increase to export of laver products, we urgently require to open foreign trade of laver products for Japanese consumer, .and Japan has political responsibility to solve Korean laver structure. But with long run timeseries, as regards Japanese production and import quantity, importing function shows increasing trend as below, 250 million sheets <3, 947.1674+0.005 $L_{g}$ >) 600 million sheets where $L_{q}$ is relative production quantity of laver in Japan. (unit; 100 thousand sheets) Our Export effort should be put on the highly processed products whithin the restraind quote.ote.

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Schematic Maps of Ocean Currents in the Yellow Sea and the East China Sea for Science Textbooks Based on Scientific Knowledge from Oceanic Measurements (관측 기반 과학적 지식에 근거한 과학교과서 황해 및 동중국해 해류모식도)

  • PARK, KYUNG-AE;PARK, JI-EUN;CHOI, BYOUNG-JU;LEE, SANG-HO;SHIN, HONG-RYEOL;LEE, SANG-RYONG;BYUN, DO-SEONG;KANG, BOONSOON;LEE, EUNIL
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.22 no.4
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    • pp.151-171
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    • 2017
  • Most of oceanic current maps in the secondary school science and earth science textbooks have been made on the base of extensive in-situ measurements conducted by Japanese oceanographers during 1930s. According to up-to-date scientific knowledge on the currents in the Yellow Sea and the East China Sea (YES), such maps have significant errors and are likely to cause misconceptions to students, thus new schematic map of ocean currents is needed. The currents in the YES change seasonally due to relatively shallow water depths, complex terrain, winds, and tides. These factors make it difficult to construct a unified ocean current map of the YES. Sixteen major items, such as the flow of the Kuroshio Current into the East China Sea and its northward path, the origin of the Tsushima Warm Current and its path into the Korea Strait, the path of Taiwan Warm Current, the Jeju Warm Current, the runoff pattern of the Yangtze River flow, the routes of the northward Yellow Sea Warm Current, the Chinese Coastal Current, and the West Korea Coastal Current off the west coast of the Korean Peninsula, were selected to produce the schematic current map. Review of previous scientific researches, in-depth discussions through academic conferences, expert discussions, and consultations for three years since 2014 enabled us to produce the final ocean current maps for the YES after many revisions. Considering the complexity of the ocean currents, we made seven ocean current maps: two representative current patterns in summer and winter, seasonal current maps for upper layer and lower layer in summer and winter, and one representative surface current map. It is expected that the representative maps of the YES, connected to the current maps of the East Sea and the Northwest Pacific Ocean, would be widely utilized for diverse purposes in the secondary-school textbooks as well as high-level educational purposes and even for scientific scholarly experts.

Spatiotemporal Variations of Seawater Quality due to the Inflow of Discharge from Nakdong River Barrage (낙동강 하구둑 방류수에 의한 하구역 수질의 시공간적 변화)

  • Yoon, H.S.;Park, S.;Lee, I.C.;Kim, H.T.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.11 no.2
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    • pp.78-85
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    • 2008
  • We estimated the pollutant loads for the last 3 years based on the daily discharge at the Nakdong River dam(barrage) and spatiotemporal characteristics of seawater quality in the Nakdong river estuary to investigate the correlation between the pollutant load inflow rate and seawater quality. The main results from this research are summarized as follows. (1) The total discharge at the Nakdong River dam dam the last 11 years has been $224,576.8{\times}10^6m^3/day$. The discharge figures show that the maximum discharge occurs in August with $52,634.2{\times}10^6 m^3/day$ (23.4% of the year's volume), followed by July and Sep. in that order with 23.1 and 17%, respectively. (2) The pollutant load influx from the Nakdong River dam was composed of 307,591.3COD-kg/day, 128.746.1 TN-kg/day, and 107,625.8 TP-kg/day. (3) The surface temperature in the Nakdong River estuary was about $2.137^{\circ}C$ higher than that of the lower layer. The salinity of the lower layer was 2.209%o higher than that of the ocean surface. The salinity of the ocean surface decreased by up to 19.593%o due to the inflow of the discharge at the Nakdong River dam. (4) DO, COD, TN, and SS concentration levels tended to be higher at the ocean surface than in lower layers, whereas the reverse was true for TP. (5) The water mass at the ocean's surface and in the lower layers during the drought and flood seasons tended to be separated by the difference in densities due to the freshwater inflow.

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Influence of Gibberellin and Urea treatment on the Production of mulberry leaf and characteristic of silkworm (지베렐린과 요소의 처리가 상수의 수량 및 잠아의 실용형질에 미치는 영향)

  • 유근섭;오준식
    • Journal of Sericultural and Entomological Science
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    • v.9
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    • pp.27-34
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    • 1969
  • This study was conducted investigate the effect of Gibberellin and Urea on the growth of mulberry tree with the compound treatment, and the characteristic of silkworm when the mulberry leaves simply treated with GB and the compound treatment with GB and Urea were supplied. The results are as follows. 1. Mulberry tree A. The leaf weight per mulberry tree with the compound treatment of GB+ Urea was heavier in spring silkworm and the leaf yield was increased by 7% compared with the non-treatment plot. B. The growth of wattle, leaf length and leaf width was more accelerated in the compound treatment plot of GB+Urea, the single treatment plot of GB and Urea than th!: non-treatment plot in autumn silkworm, and there was observed an incredse yielding effect of 16% in GB+Urea plot, in 16% GB plot and 18% in Urea plot respectively as compared with th: non-treatment plot, hut yield per l000m unit of wattle length was the least in GB plot. C. In the composition of mulberry leaves of treatment, water and crude protein was increased in the compound treatment plot of GB + Urea and the single treatment plot of GB and Urea than the non-treatment plot, but dry matter and carbohydrate were decredsed. 2. Characteristics of Larva in spring silkworm A. The mortality ratio of 4 and 5 instar plot was equally high in the compound treatment plot of GB+ Urea and the pupation ratio of 4 instar plot was lower than other treatment plot. B. Although there was no significant difference observed in the cocoon weight of 10.000 1st-day worms in both 4 and 5 instar plots between each treatment plot, the single treatment plot of GB showed somewhat great than other treatment plots. C. There was no significant difference observed in the cocoon layer ratio between each treatment plot, but 4 instar plots was slightly higher than 5 instar plots. 3. Characteristics of Larva in Autumn silkworm A. The mortality ratio of the compound treatment plot of GB+ Urea and GB was higher than that of the nontreatment and single treatment plot of Urea. B. The pupation ratio of the single treatment plot of Urea was higher than that of the compound treatment plot of GB + Urea, and there was no significant difference observed between other treatment plot. C. The cocoon weight of 10.000 1st-day th instar worms was heavier in the single treatment plot of Urea than nontreatment plot, GB+Urea plot and GB plot. D. The cocoon layer ratio was no significant difference observed between each-treatment.

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Characteristic for Long-term Trends of Temperature in the Korean Waters (한국 연근해 수온의 시공간적 장기변동 특성)

  • Seong, Ki-Tack;Hwang, Jae-Dong;Han, In-Seong;Go, Woo-Jin;Suh, Young-Sang;Lee, Jae-Young
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.16 no.4
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    • pp.353-360
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    • 2010
  • The result of analysis of the observed temperature data by the Serial Oceanography Investigation of National Fisheries Research and Development Institute (NFRDI) during last 41 years from 1969 to 2008 showed that sea surface temperatures in the East, West and South Sea of Korea were clearly increased. In case of 100m depth, temperature was increased in the South Sea of Korea, but it was decreased in the East Sea. Especially, the temperature around the coastal area in the East Sea was significantly decreased by the spatial distribution of long-term change of temperature on 100m depth. It should lead to the decreasing trend in the long-term change of temperature on 100 m depth in the entire East Sea. The increasing trend was clearly larger in wintertime than in summertime by a factor of about 2 It means that the long-term increasing trend of sea surface temperature in the Korean Waters is usually caused by the distinctive increasing trend in wintertime. As the results of the analysis of air temperature and wind speed on the 6stations around the coastal area in the Korean Waters, air temperature was found to be continuously increased, but wind speed to be gradually decreased in winter. The weakness of vertical mixing by decreasing of wind speed caused to make the surface mixed layer shallow. it could be considered that the increasing trend of surface temperature was caused by weak mixing between surface and intermediate layers.

Effect of Dietary Phytase on the Excreta Excretion of Laying Hens (사료 내 Phytase 첨가가 산란계의 분뇨 배설량에 미치는 영향)

  • Hong, E.C.;Na, S.H.;Yu, D.C.;Kim, H.K.;Park, M.N.;Jung, K.C.;Choo, H.J.;Park, H.D.;Chung, W.T.;HwangBo, J.
    • Korean Journal of Poultry Science
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    • v.36 no.3
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    • pp.257-264
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    • 2009
  • This work was conducted to investigate the effects of phytase on N and P excretion of laying hens excreta. Three hundred sixty ISA Brown layers were selected to investigate excreta excretion for 65 weeks and to investigate the effect of phytase on total excretion and N and P excretion of layers from 55 weeks. The experimental diets were fed the starter (0~5 wk), grower (5~12 wk), developer (12~16 wk), prelay diets (16 wk~first egg), layer diets for starting period (first egg~32 wk), middle (32~45 wk), finishing diets (45~55 wk, 55 wk~). Thirty ISA Brown layers were selected to investigate the effect of phytase supplementation on total N and P excretion of layers at 55 weeks and assigned randomly to 3 treatments groups (10 birds/treatment) and phytase was added to basal diets at 300 and 600 FTU/kg. Average body weight, feed intake, water intake, and excreta excretion were 1,622, 105.7, 187.2 and 124.7 g/bird/day, respectively. Excreta of birds fed phytase were DM (33.2, 31.2, 30.5 g/day), N (0.46, 0.42, 0.40 g/day) and P (0.51, 0.49, 0.48 g/day) and reduced as dietary phytase increased, Finally, dietary phyase can reduce the N and P excretion, but the amount of excreta was not different depending from the phytase addition in layers. This work investigated the N and P excretion of laying hens excreta and were considered that dietary phytase can reduce the N and P excretion for short period.

Basic Studies on the Consumptive Use of Water Required for Dry Field Crops (2) -Garlic and Cucumber- (밭작물소비수량에 관한 기초적 연구(II)-마늘 및 오이-)

  • 김철기;김진한;정하우;최홍규;권영헌
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.31 no.3
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    • pp.41-56
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    • 1989
  • The purpose of this study is to find out the basic data for irrigation plans of garlic and cucumber during the growing period, such as total amount of evapotranspiration, coefficients of evapotranspiration at each growth stage, the peak stage of evapotranspiration and the maximum evapotranspiraton, optimum irrigation point, total readily available moisture, and intervals of irrigation date. The plots of experiment were arranged with split plot design which were composed of two factors, irrigation point for main plot and soil texture for split plot, and three levels ; irrigation points with pP 1.7-2.1, pP 2.2-2.5, pP 2.6-2.8, for garlic and those with pP 1.9, pF 2.3, pP 2.7, for cucumber, soil textures of silty clay, sandy loam and sandy soil for both garlic and cucumber, with two replications. The results obtained are summarized as follows 1.There was the highest significant correlation between the avapotranspiration of garlic and cucumber and the pan evaporation, beyond all other meteorological factors considered, as mentioned in the previous paper. Therefore, the pan evaporation is enough to be used as a meteorological index measuring the quantity of evapotranspiration. 2.1/10 probability values of maximum total pan evaporation during growing period for garlic and cucumber were shown as 495.8mm and 406.8mm, respectively, and those of maximum ten day pan evaporation for garlic and cucumber, 63.8mm and 69.7mm, respectively. 3.The time that annual maximum of ten day pan evaporation can be occurred, exists at any stage between the middle of May and the late of June(harvest period) for garlic, and at any stage of growing period for cucumber. 4.The magnitude of evapotranspiration and of its coefficient for garlic and cucumber was occurred in the order of pF 1.7-2.1>pF 2.2-2.5>pF 2.6-2.8 and of pF 1.9>pF 2.3>pF2.7 respectively in aspect of irrigation point and of sandy loam>silty clay>sandy soil in aspect of soil texture for both garlic and cucumber. 5.The magnitude of leaf area index was shown in the order of pF 2.2-2.5>pF 1.7-2.1>pF 2.6-2.8 for garlic and of pF 1.9>pF 2.3>pF 2.7 for cucumber in aspect of irrigation point, and of sandy loam>sandy soil>silty clay in aspect of soil texture for both garlic and cucumber. 6.1/10 probability value of evapotranspiration and its coefficient during the growing period for garlic were shown as 391.7mm and 0.79 respectively, while those of cucumber, 423.lmm and 1.04 respectively. 7.The time the maximum evapotranspiration of garlic can be occurred is at the date of thirtieth before harvest period and the time for cucumber is presumed to be at the date of sixtieth to seventieth after transplanting, At that time, 1/10 probability value of ten day evapotranspiration and its coefficient for garlic is presumed to be 65.lmm and 1.02 respectively, while those of cucumber, 94.8mm and 1.36 respectively. 8.In aspect of irrigation point, the weight of raw garlic and cucumber were increased in the order of pF 2.2-2.5>pF 1.7-2.1>pF 2.6-2.8 and of pF 1.9>pF 2.3>pF 2.7 respectively. Therefore, optimum irrigation point for garlic and cucumber is presumed to be pF 2.2-2.5 and pF 1.9 respectively, when the significance of yield between the different irrigation treatments is considered. 9.Except the mulching period of garlic that soil moisture extraction patterns were about the same, those of garlic and cucumber have shown that maximum extraction rate exists at 7cm deep layer at the beginning stage after removing mulching for garlic and at the beginning stage of growth for cucumber and that extraction rates of 21cm to 35cm deep layer are increased as getting closer to the late stage of growth. 10.Total readily available moisture of garlic in silty clay, sandy loam, sandy soil become to be 18.71-24.96mm, 19.08-25.43mm, 10.35- 13.80mm respctively on the basis of the optimum irrigation point with pF 2.2-2.5, while that of cucumber, 11.8lmm, 12.03mm, 6.39mm respectively on the basis of the optimum irrigation point with pF 1.9. 11.The intervals of irrigation date of garlic and cucumber at the growth stage of maximum consumptive use become to be about three and a half days and one and a half days respectively, on the basis of each optimum irrgation point.

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