• 한국작물학회지
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• 제26권3호
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• pp.257-262
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• 1981

Orchardgrass 초지에 있어서 조성 초기의 질소시비에 대한 생장 및 수량반응과 질소이용성에 관한 기초자료를 얻기 위하여 1979년 4월에 서울대 농대 실험 농장에서 품종 Potomac을 파종하여 연간 100, 200, 400, 800 kg/ha 수준의 질소비료 시용실험을 난괴법 3반복으로 수행하였다. 그 결과는 다음과 같았다. 1. 파종 첫해의 최대 건물수량 및 최대 질소회수율을 보인 수준은 200kg.N/ha.year였으나 다음 해에는 400kg.N/ha.year였다. 2. 재생기간중의 엽면적지수(LAI)와 순동화율(NAR) 및 체내 전질소함량은 질소증시와 함께 증가했으며 최대 작물생장속도(CGR)는 LAI 5 정도에서 얻어졌다. 3. 채내 ${NO_3}^-$-N 농도는 연간 200kg.N/ha 수준 이상에서 급격히 증가하여 800kg.N/ha 수준에서 중독위험치(1,500ppm ${NO_3}^-$-N)를 초과하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제4권4호
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• pp.341-351
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• 1991

Sixteen Holstein heifer calves were used in an 112-day trial to study the effects of probiotic supplementation on growth performance and rumen metabolism. Calves were divided into four groups of four calves each, with two groups receiving the probiotic supplement and two groups serving as controls. Calves were limited to 1.6 kg dry matter of a corn-barley based grain mix per day. Long-stem bromegrass hay was fed as forage the first 56 days and bromegrass silage the last 56 days of the trial. Probiotic (28 g/d/calf) was fed along with the grain mix twice daily. Data were analyzed for the entire trial and also for the separate hay and silage feeding periods. Total weight gain and average daily gain were not affected (p>.05) by probiotic supplementation. Dry matter intake was lower (p<.05) and feed efficiency (kg feed/kg weight gain) was improved slightly during the hay feeding period for the probiotic-supplemented calves. Wither height gain was greater (p<.05) during the hay period and lower (p<.05) during the silage period for probiotic-supplemented calves. Heart girth gain was improved (p<.07) by probiotic supplementation, particularly during the hay feeding period (p<.05). Total rumen volatile fatty acid (VFA) concentration was higher (p<.05) with the probiotic-supplemented calves. Molar proportions of individual VFA were not affected (p>.05). Rumen ammonia-N and plasma urea-N concentration were lower (p<.05) for probiotic-supplemented calves during the hay feeding period. Total tract nutrient digestibility was not affected (p>.05). Some improvements in animal performance and changes in rumen and blood metabolites were observed when calves were supplemented with probiotic. Effects due to probiotic supplementation were most pronounced during the hay feeding period.

• 대기
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• 제21권3호
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• pp.301-309
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• 2011

In this study, we compared light-absorption properties of aerosols observed in East and South Asia from black carbon (BC) mass concentration, aerosol scattering (${\sigma}_s$) and absorption (${\sigma}_a$) coefficients measurements at four sites: Korea Climate Observatory-Gosan (KCO-G), Korea Climate Observatory-Anmyeon (KCO-A), Maldives Climate Observatory-Hanimaadhoo (MCO-H) and Nepal Climate Observatory-Pyramid (NCO-P). No significant seasonal variations of BC mass concentration, ${\sigma}_s$ and ${\sigma}_a$, despite of wet removal of aerosols by precipitation in summer, were observed in East Asia, whereas dramatic changes of light-absorbing aerosol properties were observed in South Asia between dry and wet monsoon periods. Although BC mass concentration in East Asia is generally higher than that observed in South Asia, BC mass concentration at MCO-H during winter dry monsoon is similar to that of East Asia. The observed solar absorption efficiency (${\alpha}$) at 550 nm, where ${\alpha}={\sigma}_a/({\sigma}_s+{\sigma}_a)$, at KCO-G and KCO-A is higher than that in MCO-H due to large portions of BC emission from fossil fuel combustion. Interestingly, ${\alpha}$ at NCO-P is 0.14, which is two times great than that in MCO-H and is about 40% higher than that in East Asia, though BC mass concentration at NCO-P is the lowest among four sites. Consistently, the highest elemental carbon to sulphate ratio is found at NCO-P.

• Asian-Australasian Journal of Animal Sciences
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• 제19권3호
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• pp.381-385
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• 2006

This study examined the influence of re-growth periods on chemical composition, biomass production, nutritive value and digestion kinetics of Setaria sphacelata (SS) and Cenchrus ciliaris (CC) in ruminally cannulated buffalo bulls. Two re-growth intervals i.e. clipping every month ($CI_1$) and clipping after every two months ($CI_2$) were compared with the control (clipped after 4 months). Mean values of leaf to stem ratio in SS and CC grasses were decreased (p<0.05) with increasing re-growth interval. The lowest leaf to stem ratio was recorded in control plots of both grasses. In both grasses, increasing growth period increased the concentrations of dry matter (DM), neutral detergent fiber (NDF) and organic matter (OM) and decreased crude protein (CP). Mean dry herbage, OM and CP yields of SS and CC were increased (p<0.05) with increasing re-growth interval. Ruminal DM and NDF digestibilities of SS and CC were decreased (p<0.05) with increasing interval. Ruminal rate of DM and NDF disappearance was higher while the ruminal lag time of these nutrients was lower with monthly than with bi-monthly clipping interval. The results from present study imply that SS and CC clipped after every two months is more beneficial than when clipped every month or every four months in terms of optimal biomass with adequate nutritional value for buffaloes.

• 한국작물학회지
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• 제29권4호
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• pp.321-327
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• 1984

벼 재배시에 나타나는 주연효과의 품종간 차이와 생장해석을 통한 주연효과의 원인을 알고져 3품종을 공시하여 시험한 결과를 요약하면 다음과 같다. 1. 논의 외연 1∼2 열에 심겨진 벼의 수량은 내부열에 비하여 평균 30％ 정도 많았는데 주연효과는 품종에 따라서 최대 35％, 최소 21％이었다. 2. 주연효과에 의한 수량증가는 논의 외부 1∼2열에서만 나타났으나 한강찰벼는 외연으로부터 4열까지도 주연효과가 나타났다. 30 주연효과는 주당수수와 수당입수에서 현저하게 나타났다. 4. 수건물중과 엽면적은 이앙후 30∼60일경부터 외열과 내열간에 차이가 나타났는데 조생종은 중만생종보다 주연효과에 의한 건물중과 엽면적의 차이가 빨리 나타났다. 5. 개체군생장속도, 상대생장율, 순동화율 및 엽면적비 등에 있어서도 주연효과를 나타내는 시기가 많았다.

• 환경영향평가
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• 제21권1호
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• pp.25-39
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• 2012

This study was aimed to assess the effects of additional installation of two different types of weirs, one is a curtain-type weir and another is a submerged-type weir, on the control of algal growth in Daechung Reservoir. A two-dimensional(2D) coupled hydrodynamic and eutrophication model that can accommodate vertical movement of the curtain weir following the water surface variations was verified using field data obtained in two distinctive hydrological years; dry(2008) and wet(2010). The model adequately simulated the temporal and spatial variations of water temperature, nutrients and algal(Chl-a) concentrations during the periods. The effectiveness of curtain weir on the control of algal bloom was evaluated by applying the model to 2001(dry year) and 2010 assuming 6 different scenarios according to installation locations. The curtain weirs that already installed at 3, 5, 7 sites(scenario C-2) showed significant effect on the control of algal growth in the reservoir; the reduction rates of algal concentration were placed in the range of 7.5~31.5% and 9.1~44.9% for 2001 and 2010, respectively. However the simulation results revealed that additional installation of curtain weirs(scenario C-3~C-6) in the bay area (choosori) have marginal effect. The effectiveness of submerged weir was evaluated against 2010 assuming 7 different scenarios according to installation locations, but all scenarios(S-1~S-7) showed neglectable or negative effect on the control of algal growth.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.243-243
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• 2015

Low-flow simulation and forecasting is one of the emerging issues in hydrology due to the increasing demand of water in dry periods. Even though low-flow simulation and forecasting remains a difficult issue for hydrologists better simulation and earlier prediction of low flows are crucial for efficient water management. The UN has never stated that South Korea is in a water shortage. However, a recent study by MOLIT indicates that Korea will probably lack water by 4.3 billion m3 in 2020 due to several factors, including land cover and climate change impacts. The two main situations that generate low-flow events are an extended dry period (summer low-flow) and an extended period of low temperature (winter low-flow). This situation demands the hydrologists to concentrate more on low-flow hydrology. Korea's annual average precipitation is about 127.6 billion m3 where runoff into rivers and losses accounts 57% and 43% respectively and from 57% runoff discharge to the ocean is accounts 31% and total water use is about 26%. So, saving 6% of the runoff will solve the water shortage problem mentioned above. The main objective of this study is to present the hydrological modelling approach for low-flow simulation and forecasting using a model that have a capacity to represent the real hydrological behavior of the catchment and to address the water management of summer as well as winter low-flow. Two lumped hydrological models (GR4J and CAT) will be applied to calibrate and simulate the streamflow. The models will be applied to Seolmacheon catchment using daily streamflow data at Jeonjeokbigyo station, and the Nash-Sutcliffe efficiencies will be calculated to check the model performance. The expected result will be summarized in a different ways so as to provide decision makers with the probabilistic forecasts and the associated risks of low flows. Finally, the results will be presented and the capacity of the models to provide useful information for efficient water management practice will be discussed.

• 농업생명과학연구
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• 제53권2호
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• pp.15-26
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• 2019

In vivo 측정법은 비용이 많이 들고 연구기간이 길며 동물복지 측면에서 여러 문제점이 있다. 이에 대한 대안으로 지난 수십년간 in vitro 소화율 측정법이 개발되어 왔다. 본 총설에서는 대표적인 단위 동물로써 사양되고 있는 돼지의 소화기관 특징 및 소화작용에 대한 논하였다. 또한, 최근에 개발된 daisy II incubator 를 이용한 in vitro 방법을 통해 돼지에서 주요 곡류사료로 이용되고 있는 옥수수, 쌀, 소맥 및 대맥의 회장 및 전분 건물소화율을 측정하였다.

• Journal of Animal Science and Technology
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• 제63권2호
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• pp.354-366
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• 2021

Limited data about the effects of various factors on forage quality and β-carotene content of rye produced in Korea are available, so this study investigated the effects of two preservation methods. Samples were collected from rye harvested every 5 days between April 25 and May 31, and comparisons were done among rye silage wilted for different periods of time and hay of three growth stages of rye. For the silage, dry matter (DM), acid detergent fiber (ADF), and neutral detergent fiber (NDF) contents increased with advanced maturity of rye, whereas crude protein, in vitro dry matter digestibility (IVDMD), total digestible nutrients (TDN), relative feed value (RFV), and DM loss decreased (p < 0.0001). Wilting increased the DM content and pH value significantly (p < 0.0001). Silage harvested at the heading stage had the lowest pH value (4.45), propionic acid (0.83 g/kg DM), butyric acid (0 g/kg DM), and fungi and yeast populations (3.70 Log CFU/g of fresh matter [FM]); conversely, it had the highest lactic acid (9.7 g/kg DM), lactic acid bacteria (LAB) (6.87 Log CFU/g of FM), total microorganisms (TM) (7.33 Log CFU/g of FM), and Flieg's score (70) (p < 0.0001). Wilting elevated LAB and TM populations, but it had no consistent effect on other fermentation products. Both delayed harvest and prolonged wilting decreased β-carotene content. Rye silage harvested around May 9 (heading stage) with 24 h of wilting was preferred for highland, Pyeongchang. For rye hay, advanced maturity decreased DM loss, IVDMD, TDN, and RFV, but it increased DM, ADF, and NDF significantly (p < 0.05). β-carotene was decreased by delay of hay-making. Consequently, to attain lower DM loss and higher hay quality, the harvest date of May 9 (heading stage) is recommended.

• 한국초지조사료학회지
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• 제5권1호
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• pp.13-21
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• 1985

본(本) 시험(試驗)은 추파(秋播) 이탈리안라이그라스의 추계예취시취(秋季刈取時取)가 목초(牧草)의 재생(再生), 탄수화물축적(炭水化物蓄積) 및 건물수량(乾物收量)에 미치는 영향을 구명(究明)하기 위(爲)하여 포장시험(圃場試驗)을 수행(遂行)하였으며 결과(結果)를 요약(要約)하면 다음과 같다. 1. 건물수량(乾物收量)은 예취시기(刈取時期)가 빠른 구(區)일수록 높았고(P<0.05), 예취시기(刈取時期)가 제일 늦은 구(區)는 무예취구(無刈取區) 보다도 수량(收量)이 낮았다. 2. 건물중(乾物中) 전수용성탄수화물(全水溶性炭水化物)(TSC)의 함량(含量)은 일번예취직후(一番刈取直後)에 약간(若干) 떨어졌다가 재생장(再生長)에 따라 점점(漸漸) 높아졌으며 이번초(二番草) 예취기(刈取期)에 가까울수록 다시 떨어졌다. 기온(氣溫)이 영하(零下)로 하강(下降)하기 1주일전(週日前)의 TSC 함량수준(含量水準)은 그루터기, 줄기, 잎 별(別)로 모두 예취시기(刈取時期)간 빠른 구(區)일수록 고수준(高水準)이었으며 (P<0.01), 이번초(二番草)와 건물수량(乾物收量)과의 사이에 상관(相關)이 성립(成立)되었다(P<0.05) 3. 개체군(個體群) 생장속도(生長速度)(CGR)는 평균기온(平均氣溫)이 $8^{\circ}C$에서 하강(下降)할수록 떨어졌으며 상승(上昇)할수록 높았다. 상대엽면적생장율(相對葉面積生長率)(RLGR)과 순동화율(純同化率)(NAR)은 각구(各區) 모두 재생(再生)30일간(日間)이 가장 높았으며 재생후기(再生後期)에는 저하(低下)되었다. 엽면적지수(葉面積指數)(LAI)의 증대(增大)는 각구(各區) 모두 예취후(刈取後) 50일(日)까지는 빨랐으며 그 후(後)에는 완만하였고 최대치(最大値)의 범위(範圍)는 $3.4{\sim}5.8$이었다. 또한 예취후(刈取後) 70일(日)까지의 LAI가 큰 구(區)일수록 이번초(二番草)의 건물수량(乾物收量)이 높았다. 4. 생장(生長)이 억제(抑制)되는 저온기(低溫期)의 TSC, LAI ,CGR, NAR 및 LWR와 이번초건물수량(二番草乾物收量)과의 사이에 상관(相關)이 인정(認定)되엇으며, 그 공헌도(貢獻度)는 LWR>LAI>TSC>NAR>CGR의 순(順)이었다.