• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.10 no.1
• /
• pp.1-18
• /
• 1974

Some coastal oceanographic investigations in Kwang Yang Bay were carried out bimonthly from April to September (The first half period of the research project) in 1974. The behaviour of the waters, distributions of water temperature and salinity and diffusion characteristic by dye release experiments in the bay are studied for the problems of practical importance in connection with water pollution. Velocities and directions of tidal currents at five fixed stations were observed. And dye diffusion experiment was also carried out on the sea. According to the results from this study, the salinity of the water is lower, ranging from about $28\;\textperthousand\;to\;32\textperthousand$, on all over the surface in the bay with the cause that the fresh water flows in from the Sumjin river. Diffusivities in this sea by means of Rhodamine B diffusion elliperiment were $785.6\;{\times}\;10^2\;\textrm{m}^2/sec$ in major axis, $15.6\;{\times}\;10^2 \;\textrm{m}^2/sec$/sec in minor axis in the direction on patch after 30 minutes from the dye release.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.6
• /
• pp.400-404
• /
• 2000

Hairy vetch (vicia villosa Roth), leguminous green manure crop, can increase soil fertility and reduce chemical nitrogen application for cash crop such as spring corn. More yield of hairy vetch is needed at planting cash crop to obtain higher effect of green manure. Hairy vetch waa seeded on Sep.10, Oct.1, and Oct. 20 and at 10, 20, 30 and 40 kg/ha of seeding rate respectively, in 1996 and 1997, Dry matter and nitrogen yield of hairy vetch were measured on May 1 in 1997 and 1998. Proper seeding rate of hairy vetch was 30 kg/ha irrespective of years and seeding dates. Above-ground dry matters of hairy vetch on May 1 in 1997 and 1998 decreased according to delayed seeding, and those were 5.5-7, 4-4.5, 1.3-2.2 ton/ha on Sep. 10, Oct. 1 and Oct 20 of seeding date, respectively in seeding rate 30-40 kg/ha. Also nitrogen yield of hairy vetch on May 1 decreased according to delayed seeding, and those were 220-280, 160-180, 60-100kg/ha on Sep. 10, Oct. 1 and Oct 20 of seeding date, respectively in seeding rate 30-40kg/ha. Therefore, we suggest that hairy vetch has to be seeded earlier in autumn to obtain high green manure yield in spring. To determine the detailed optimum seeding time in autumn, hairy vetch was seeded on Aug. 20, Aug. 31, Sep. 10, Sep. 20, and Sep. 30 in 1999 and was harvested on April 22, April 27, and May 2 in 2000, respectively. Dry matter and nitrogen yield of hairy vetch by seeding in late August were higher than those by seeding in September indicating that dry matter of hairy vetch were 7-8, 6-7, 4-5, 2-3 ton/ha and nitrogen yield were 240-290, 200-260, 150-220, 70-120 kg/ha, respectively when seeded on Aug. 20, Aug. 31, Sep. 10, Sep. 20 and Sep. 30 and harvested on April 22-May 2. Increase of dry matter and N yield of hairy vetch by 10days delayed harvest was higher in late August seeding than in September seeding. So hairy vetch should be seeded in late August if possible to obtain much more green manure yield and be seeded until September because green manure yield decrease rapidly when seeded after October.

• The Korean Journal of Malacology
• /
• v.23 no.2
• /
• pp.189-198
• /
• 2007

The reproductive cycle, egg capsules in the egg-mass, first sexual maturity, and sex ratio of the bladder moon, Glossaulax didyma ($R\ddot{o}ding$) were investigated. The gastropods collected from the intertidal zone of Biin Bay, Seocheon, Korea were studied by using histological analysis and morphometric data. The gonadosomatic index (GSI) of females and males began to increase in March and reached maximum in May. Then their values sharply decreased from late in May to August due to spawning. The condition index (CI) began to increase in February and reached maximum in May, then gradually declined in the spawning period. The CI calculated for determination of the spawning period was coincided with changes in the GSI and gonadal phases. Spawning occurred between late in May to August in females and early in May to August in males. Spawning peak was observed between July and August when the seawater temperature rose to 19 $^{\circ}C$. Reproductive cycle with the gonadal development phases of this species can be divided into five successive stages in females and four in males: in females, early active stage (December to February), late active stage (February to March), ripe stage (April recovery stage (August to November); in males, active stage (December to March), ripe stage (March to July), copulation stage (early May to August), and recovery stage (August to January). Fully matured oocytes were approximately 250-270 ${\mu}m$ in size. The egg-mass was a hat in shape, and a number of egg capsules were found in an egg-mass. An egg capsule was 0.53-0.57 mm in size. An embryo (veliger larva) hatched from an egg capsule. Percentage of first sexual maturity in females and males were over 50% for individuals that are 40.1-45.0 mm in shell radius, and 100% for those that are over 45.1 mm. The sex ratio of female to male was significantly different from 1:1 $(x^2\;=\;57.22,\;p\;<\;0.05)$.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.34 no.2
• /
• pp.163-169
• /
• 1989

Seasonal climatic factors associated with tobacco quality grade and production rate were analyzed. The degree of influence on yield distribution rate in high guality tobacco leaues was highly positive with the average temperature in early May, but negatively related to those in late May and early June. Positive correlations were noticed between the degree of influence and sunshine hours in Middle June, late June and late May in decrease order, while negative degree of influence was higher in early May than in late May, The order influenced by recipitation in a positive direction was early May, late May and middle May. Negative influence was noticed in middle and early June with a great degree.

• Food Science of Animal Resources
• /
• v.26 no.2
• /
• pp.245-251
• /
• 2006

This study was performed to investigate the changes of vitamin A, vitamin E, vitamin $B_l$ and vitamin $B_2$ contents in cow's raw milk collected from dairy farms in Chungcheong-do and Jeolla-do for a year. The contents of fat soluble vitamin A and E were changed as seasonal effect, but water soluble vitamin $B_l$ and $B_2$ contents were not changed as seasonal effect. Vitamin A content in cow's raw milk was as follows [minimum ${\sim}$maximum (mean), ug/100 mL]; $35.1{\sim}59.0$ (44.4) in spring, $36.7{\sim}65.6$ (50.0) in summer, $28.7{\sim}61.2$ (46.8) in autumn and $29.9{\sim}57.8$ (43.1) in winter. In case of vitamin E was as follows [minimum${\sim}$maximum (mean), ug/100 mL]; $28.3{\sim}59.2$ (45.8) in spring, $39.6{\sim}69.9$ (58.8) in summer, $35.0{\sim}62.8$ (46.2) in autumn and $26.0{\sim}55.4$ (41.5) in winter. In case of vitamin $B_l$ was as follow [minimum${\sim}$maximum (mean), ug/100 mL]; $27.7{\sim}57.9$ (42.84) in spring, $32.4{\sim}66.1$ (49.39) in summer, $34.1{\sim}63.7$ (46.69) in autumn and $20.6{\sim}61.4$ (43.20 in winter. The amounts of vitamin $B_2$ in cow's raw milk was as follows [minimum${\sim}$maximum (mean), ug/100 mL]; $150{\sim}182$ (160 in spring, $145{\sim}185$ (163) in summer, $149{\sim}180$ (166) in autumn and $148{\sim}190$ (167) in winter.

• KAPE Magazine
• /
• s.163
• /
• pp.4-5
• /
• 2010

한국농촌경제연구원이 지난 2월 25일에 발표한 2010년 2/4분기 축산관측에 따르면 '10년 3~5월 수소 한우 평균은 530~550만원으로 전망됐다. 돼지의 '10년 3~4월 성돈 가격은 110kg 기준으로 32~33만원, 4월 육계 산지가격은 2,000~2,200원으로 전망했다. 본지는 축종별 전망 내용을 요약 게재한다.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2000.05a
• /
• pp.243-244
• /
• 2000

낙동강 중류에서 조사된 식물플랑크톤상은 7강 42속 77종류였고 Bacillariophyceae가 43종류(55.8%), Chlorophyceae 24종류(31.2%), Cyanophyceae 4종류(5.2%), Dinophyceae와 Euglenophyceae이 각각 2종류(2.6%), Chrysophyceae와 Cryptophyceae가 각각 1종류 (1.3%)였다. 주요종은 Stephanodiscus hantzschii를 비롯한 6속 7종류였고 모두 규조류였다. 현존량은 최저 79 cells/$m{\ell}$(3월, 고령)에서 최고 33,023 cells/$m{\ell}$(2월, 물금)로 나타났다. 우점도지수는 최저 0.434(8월, 남지), 최고 0.999(1월, 2월, 물금)였다. 종다양성지수는 최저 0.026(2월, 물금), 최고 3.073(9월, 남지)로 조사되었다.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.12 no.2
• /
• pp.83-94
• /
• 2010

The objective of this study was to determine the best probability distributions of annual, seasonal and monthly precipitation in Korea. Data observed at 32 stations in Korea were analyzed using the L-moment ratio diagram and the average weighted distance (AWD) to identify the best probability distributions of each precipitation. The probability distribution was best represented by 3-parameter Weibull distribution (W3) for the annual precipitation, 3-parameter lognormal distribution (LN3) for spring and autumn seasons, and generalized extreme value distribution (GEV) for summer and winter seasons. The best probability distribution models for monthly precipitation were LN3 for January, W3 for February and July, 2-parameter Weibull distribution (W2) for March, generalized Pareto distribution (GPA) for April, September, October and November, GEV for May and June, and log-Pearson type III (LP3) for August and December. However, from the goodness-of-fit test for the best probability distributions of the best fit, GPA for April, September, October and November, and LN3 for January showed considerably high reject rates due to computational errors in estimation of the probability distribution parameters and relatively higher AWD values. Meanwhile, analyses using data from 55 stations including additional 23 stations indicated insignificant differences to those using original data. Further studies using more long-term data are needed to identify more optimal probability distributions for each precipitation.

• Journal of Aquaculture
• /
• v.11 no.2
• /
• pp.249-260
• /
• 1998

Distribution of the bivalve resorves in Deukryang Bay was investigated in May, August and November, 1995 and February, 1996. Seasonal sampling was carred out from 29 stations in Deukryang Bay. The bivalve resouces in the bay consisted of 10 species nd mean density in individuals and biomass was 3 inds./$m^2$ and 211g/$m^2$ in May, 3 inds./$m^2$ and 185g/$m^2$ in August, 2 inds./$m^2$ and 379g/$m^2$ in November, 2 inds./$m^2$ and 305g/$m^2$ in February. The dominant bivalve species in Deukryang Bay was pen shell (Atrina pectinata) through the year. Species composition and abundance of the bivalve resources were closely related to station. The stock density was high at inner stations in the bay. G1 station showed the highest density among 29 stations.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.38 no.2
• /
• pp.126-134
• /
• 2018

This study estimated the effect of sowing and harvesting dates on dry matter (DM) yield and feed value of forage oats at Sancheong, Korea. The forage oats (Darkhorse vs. Highspeed) were used in this experiment. The experimental main plots consisted of the different sowing and harvesting dates at 2 seasons as follows: spring oats of sowing (February 25, March 3 and March 13) and harvesting (May 27, June 6 and June 16); and fall oats of sowing (August 15, August 25 and September 4) and harvesting (October 15, October 25 and November 4). On spring oats, Highspeed sown on March 3 and then harvesting on June 6 had the highest (p<0.05) plant length and DM yield. Crude protein content decreased (p<0.05) in seed of the delayed-harvesting Highspeed. On fall oats, plant length and DM yield with the delayed-harvesting date increased (p<0.05), while crude protein content of the delayed-harvesting Highspeed decreased (p<0.05). This study concluded that the spring oat sown in early March and then harvesting in early June was recommended to increase dry matter and feed value although the fall oat sown in end August and then harvesting in early November was recommended for fall period.