• 한국농공학회지
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• 제14권1호
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• pp.2535-2548
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• 1972

Instead of fertilizing the lands they moved to find other fertile lands and lived a feudal life agriculture and various machincs played a main role in the land reclamation. The best method of land clearing, the time and capacity in the operation and the effect of growing crops should systematically analized prior to the time of 3rd Five-year Economic Development(1972-1976) in order to cultivate 210,000ha of wasteland or the modernization of our country. The present study was investigated to find out a new working-system of mechanical land clearing and development of fertile soil. The results are as follows: 1) The first stage of productive power increases when weeds were mixed soil in the land clearing work in order to supply organic materials and to make soil swollen instead of burning or just removing. 2) The equipments such as bulldozers, harrows, power tillers and so on should be prepared in order to do a systematic work in the land clearing. 3) The work of pulling-up roots is dependent upon the forms of roots spreading under the ground. The work of the pulling-up of the straight roots was most difficult. But before the roots are pulling-up we do not know the forms of roots. 4) The cutting of soil from upside to under side land clearing method (II) Spent 6 hr 7 min 43 sec per 1 Danbo in doing land clearing and control method spent 4 hr 52 min 30 sec per 1 Danbo in doing land cearing. No significant difference could be found between II treatment type and I treatment type. 5) The volume of soil carried by bulldozer $270.38m^3$ per 1 Danbo in I type and in II type, $368.58m^3$ per 1 Danbo or about 36% increased in II type then in I type. But that is not a significant difference when considering the whole productive power of soil. 6) The land clearing of terrace by bulldozers cannot escape making the embankment slope of about $45^{\circ}$, and 25.3% should be decreased in the area. It is recommended to make use of the embankment slope by planting grass for cows. 7) The time of retary tilling increased 2.3 times or 1 hr 42 min 22 sec per 1 Danbo compared to the timesrequired in the harrowing. Because it mixed the Organic matter on ground and the harrowing of subsoil. 8) The havest of pasture growing on the land reclamation in natural slope is as follows. (a) The none fertilizers with reclaimed block of productivity decresed 1/10 than that of the farmland. Therefore the none fer tilizing in the cultivated pasture is unprofitable. (b) The havest of the manured IV treatment block was the best not only in the kinds of fertilizers but also in the kinds of pasture grass.

• 한국농공학회지
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• 제17권1호
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• pp.3627-3641
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• 1975

The Government is trying to increase total food grain yield to meet national self sufficiency by means of increasing unit yield as well as extending crop land, and this year he set the target of 321,000 hectare of forest to clear for cropping. This study was carried to investigate the most efficient method of clearing hillock by bulldozer, and successful method to develope yielding potential of newly cleared land in short term. Since the conventional land clearing method is just earth leveling and root removing neglecting top soil treatment, the growth of crop was poor and farmer tends not to care the land. The top-soil-furrowing method is applied through out this study, that is advantageous especially for the land having shallow top soil and low fertility like Korean forest. In this study, various operating method were tried to find out most efficient method separately in connection with the land slope less than 25 percent and over, and several fertilizing methods to develop yielding potential. The results are as follows; 1) For the natural land slope utilization method, applicable to the land having less than 25 percent slope, reverse operating was more efficient than using forward gear of bulldozer. The operating time was 3 hour 32 minutes and 36 seconds using forward gear was 2 hour 32 minutes and 30 seconds for reverse gear operation per 1,000 square meter. 2) Bulldozer having angle blade adjustment needed 7hr 15min. for constructing of terrace per 10a compaire with the one having angle & tilt adjustment needed 6hr 4min for same operations. Specially there is significant difference for operation time of first period (earth cutting) such as bulldozer having angle blade adjustment needed 3hr 56min compaired with the one having angle & tilt adjustment 3hr 59min. In construction of terrace, the bull-dozer having tilting and angle blade adjustment was most suitable and performed efficiently. 3) For the fertilizer application treatment, the grass (Ladino clover) yield in first year was almost same as ordinary field's in the plot applied(N.P.K+lime+manure) while none fertilizer plot showed one tenth of it, and (N.P.K.+lime) applied plot yielded on third. 4) The effect of different land clearing method to yield showed significant difference between each treatment especially in the first year, and the conventional method was the lowest. In the second year, still conventional terracing plot yielded only half of ordinary field while the other plots showed as same as ordinary field's. 5) The downward top soil treatment plot showed most rapid improvement in soil structure during one year physio chemically, it showed increase in pH rate and organic composition, and the soil changed gradually from loam to sand-loam and the moisture content increased against the pF rate, and it gives good condition to grow hay due to the increase of field water capacity with higher available water content. 6) Since the soil of tested area was granite, the rate of soil errosion was increased about 2 to 5 percent influencing in soil structure more sand reducing clay content, and an optimum contour farming method should be prepared as a counter measure of errosion.

• 한국수정란이식학회지
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• 제16권1호
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• pp.35-40
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• 2001

Artificial insemination (AI) with frozen or cooled semen is widely used in commercial fields of cattle and pig. Little is known about characteristics of canine sperm after freezing or cooling. For both practical and commercial goal, the canine semen treated with cooling and freezing should be carried out to exam the fundamentals, including sperm motility, survivability and fertilizing capacity. The aim of this study, thus, was to identify the effects of extended exposure to 4$0^{\circ}C$ on canine semen by motility, survivability, acrosomal changes following different duration. Fifteen ejaculates collected by digital manipulation twice per week from 3 dogs (Shih-Tzu) were divided to 16 aliquots after adding Tris-egg yolk (TE) buffer formulated by our laboratory, and cooled from 37 to 4$^{\circ}C$, by ramp rate of 0.6$^{\circ}C$/min. Each sample was evaluated by their motility, survivability and the acrosomal status at 0h (control), 2h, 12h and 1 d~10 d, respectively. The motility of spermatozoa was graded to 6 levels using the modified method of Seager. The survivability of sperm was assessed using an epifluorescence microscope after Fert/Light (Mole-cular Probes Inc.) staining. To estimate the proportion of the spermatozoa of intact acrosome, 200 spermatozoa were assessed in randomly selected fields, using epifluorescence microscope after FITC/PSA (Sigma) staining. At 2 h after cooling, the motility of most spermatozoa were assessed to be grade 0 and 1. At 12 h, high number of sperm were in grade 0 to 1, however, it was significantly (P<0.05) lower than that of 2 h. From 1 d to 4 d, ~50% of sperm was assessed to grade 0 to 1. On day 7, a little sperm were in grade 0 to 1. No sperm showed motility on day 10. Sperm motility was rapidly reduced by the percent of 10% of grade 0 to 1. From 2 h to 6 h, the number of live sperm was 90% and the sperm chilled for 10 days lived>50%. Acrosomal intact of spermatozoa exposed to 4$^{\circ}C$ for 2 h was 51%, supposed the sperm of control was 100%. Our results suggest that 1) this is easy to transfer and preservation for short periods 2) AI can be used by semen chilled for 6-Day.

• 한국토양비료학회지
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• 제41권1호
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• pp.18-25
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• 2008

배추좀나방 유충의 내장으로부터 분리한 Pseudomons sp. PRGB06의 식물생장촉진능과 생물비료로서의 특성을 연구하였다. 또한 탄소원, 온도, pH, 염류농도 등의 다양한 배양 상태에서 균주의 생장을 확인하였다. 이에 더하여 Pseudomons sp. PRGB06의 진균에 대한 길항기작과 인산가용화능을 연구하였다. PRGB06 균주는 실험에 사용한 대부분의 탄소원에서 잘 자랐으며, 균주 최적 배양조건은 $30^{\circ}C$, pH7이었다. 식물병원성 진균의 억제는 균주로부터 생성된 휘발성 항진균 대사산물과 암모니아 가스로 인한 것으로 사료된다. 또한 균주는 인산가용화와 산의 생성에 크게 관여햐였으며, 뿐만 아니라 공중질소고정, 식물호르몬생성, siderophore생성, 아연가용화 등 다양한 식물생장촉진 특성을 가지고 있는 것으로 확인되었다. 이러한 PRGB06을 고추와 옥수수에 접종한 결과 뿌리길이, 유묘의 생육, 건물량이 증가하였다.

• 한국작물학회지
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• 제15권
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• pp.69-75
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• 1974

1. 질소시비를 하지않은 콩에서 개화기이후의 토양수분부족은 충분한 생육을 한 콩보다 생육일수가 3-4일 단축되었다. 2. 엽면적은 발아후 40일경까지는 처리의 영향이 컸다. 3. 경장 경경 분지수 분지장은 파종후 70일경에 거이 완성되었고 초기생육이 불량한 경우 가장 떨어졌다. 4. 질소 증시가 협수를 증가시키지 못했고 개화기의 토양수분부족은 협수를 심히 감소시켰고 이러한 콩은 분지협보다 주경협이 많았으며 또 다입협율이 높았다. 5. 주경절입별 착입수는 3-4절과 10-12절에 많았다. 3-4절에는 충분한 생육을 한 콩에서 많았고 10-12절에는 빈약한 생육을 한 콩에서 많았다. 6. 1주입수가 적은콩이 백입중은 높았다. 7. 단백질함량은 백입중이 낮은콩(N$_{0}$D$_4$)에서 가장 낮았고 유지는 1주입수가 적은콩에서 낮았다.

• 한국작물학회지
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• 제37권6호
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• pp.499-505
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• 1992

본 시험은 완효성비료를 이용한 전량기비시비방법을 개선하고자 식양토(덕평통)와 사양토(강서통)에서 완효성비료인 조선완효성비료와 Meister 15를 이용하여 시비방법에 따른 완효성비료의 시용효과를 검토한 결과는 다음과 같다. 1. 공시토양별 암모니아태 질소의 용출량은 담수 4일째 사양토에서 95ppm, 식양토에서 60ppm 이었다. 2. 벼 잎색도는 조선완효성비료가 Meister 15보다 낮았고, 시비방법간에는 측조시비구보다 전층시비구에서 높았다. 3. 질소 효율은 Meister 15 > 관행 > 조선완효성비료의 순으로 높았고, 시비방법간에는 차이가 적었다. 4. 단립면적당 경수는 조선완효성비료는 측조시비구가 전층시비구보다 많았고, Meister 15는 전층시비구가 측조시비구보다 많았으며, 간장은 Meister 15 > 관행 > 조선 완효성비료의 순으로 길었고, 시비 방법간에는 전층시비구가 측조시비구보다 길었다. 등숙율은 완효성시비가 관행보다 높았고, 시비방법간에는 전층시비구가 측조시비구보다 낮았다. 5. 수량은 식양토에서 비료간 수량차이가 컸으나, 시비방법간에는 수량차이가 적었고, 사양토에서는 비료간, 시비방법간에 수량차이가 적었다. 6. 이상의 결과에서 Meister 15와 같은 완효성비료는 전층시비법으로 시용하여도 좋을 것으로 판단되었다.

• 한국양식학회지
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• 제19권3호
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• pp.166-172
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• 2006

동일 종내 미꾸라지(Misgurnus mizolepis) 웅성발생성 인공처녀생식(intraspecific androgenesis)기술을 개발하기 위해 미꾸라지 난 유전물질의 불활성화와 이에 따른 웅성발생성 반수체 유도 조건을 최적화하였다. 다양한 자외선(UV)농도$(0\sim25,650ergs/mm^2)$를 이용하여 미꾸라지 난의 유전학적 불활성화를 시도하였으며 수정률, 부화율 및 반수체 출현율을 평가한 결과 10,800 ergs의 농도에서 가장 우수한 반수체 유도 효율을 보였으며 최초 처리 난 중 50%이상의 웅성발생성 반수체 수율을 확보할 수 있었다. 웅성발생성 개체는 전형적인 haploid syndrome의 특징을 나타내었고 flow cytometry분석 결과 정확히 미꾸라지 반수체(1.4 pg/cell)의 DNA함량을 보유하는 것으로 나타났다. 인위적으로 삽입된 형질전환 유전자 표지를 이용하여 부계 특이적인 인공처녀생식 여부를 확인하였으나 일부 반수체자어들에서$(8\sim11%)$ 모계 유전물질의 잔류가 검출되었다.

• Applied Microscopy
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• 제34권1호
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• pp.43-50
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• 2004

환경호르몬 비스페놀 A가 Xiphophorus maculatus의 생식에 미치는 영향을 알아보기 위하여 수컷을 100 ppb, 200 ppb, 400 ppb, 800 ppb의 농도에 3개월간 노출시킨 후 정상의 암컷과 교배시켜 치어수를 계수하여 수컷의 수정능력을 확인하였고, 치어를 6개월 동안 비스페놀 A에 노출시켜 치어의 암수비율, 기형율, 사망률 및 형태학적으로 정자형성과정을 조사하였다. 3개월간 비스페놀 A에 노출시킨 수컷과 정상인 암컷을 교배시켜 얻은 치어수는 정상대조군에서 평균 $19.00{\pm}3.02$마리였으나 비스페놀 A의 농도가 증가함에 따라서 치어수는 100 ppb에서 $11.50{\pm}2.22$마리, 200 ppb에서 $6.40{\pm}2.76$마리, 400 ppb에서 $5.70{\pm}1.34$마리 및 800 ppb에서 $3.70{\pm}2.11$마리로 감소하는 경향을 보였다. 치어의 암수비율은 비스페놀 A의 농도와 전혀 상관이 없었고 기형과 사망률은 0%였다. 노출시킨 지 6개월 후 정자형성과정은 800 ppb에서도 정상적으로 일어나고 있었다. 이상과 같이 비스페놀 A는 성전환, 수컷의 비율감소, 기형 및 사망에는 전혀 영향을 주지 않았고 단지 출생 개체수에만 영향을 주었다.

• Clinical and Experimental Reproductive Medicine
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• 제25권2호
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• pp.171-177
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• 1998

The combination of testicular sperm extraction (TESE) with ICSI can achieve normal fertilization and pregnancy rate and is effective method in obstructive and non-obstructive azoospermic patients. But, when pregnancy was not occurred, repeated testicular biopsies are not evitable. Therefore, in this study, we observed the survival rate of testicular spemratozoa and spermatozoa extracted from the seminiferous tubules after cryopreserved-thawed used for next IVF cycle with ICSI. In a total of 23 cases, obstructive azoospermia was 17 cases and non-obstructive azoospermia was 6 cases. In obstructive azoospermia, after thawing, motile spermatozua was observed in 13 cases (76.5%). The fertilization rate with 2PN was 67.6% and 5 pregnancies (29.4%) were achieved. In non-obstructive azoospermia, motile spermatozoa was observed in 2 case (33.3%) after thawing. The fertilization rates with 2PN was 53.7% and 3 pregnancies (50.0%) were achieved. A comparison of the results of motile spermatozoa after thawed testicular spermatozoa and spermatozoa extracted from the thawed seminiferous tubule section were 3 cases (60.0%) and 12 cases (66.6%), respectively. The fertilization and pregnancy rates of thawed testicular spermatozoa and spermatozoa extracted from the thawed seminiferous tubule section were 69.4% and 20.0%, 62.5% and 38.8%, respectively. Conclusively, thawed testicular spermatozoa and spermatozoa extracted from the thawed seminiferous tubule section can achieve normal fertilization and pregnancy and cryopreservation of testicular spermatozoa and seminiferous tubule may avoid repetition of testicular biopsies in azoospermic patients in whom the only source of spermatozoa is the testis.

• 한국동물학회지
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• 제39권4호
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• pp.437-446
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• 1996

한국산 도롱뇽(Hynobius leechii)의 암수의 신체적 특성 및 구애,싸움 행동에 대한 연구를 수행하였다. 몸의 길이, 코부터 총배설까지의 길이, 몸의 길이에 대한 코부터 총 배설강까지 길이의 비에 있어서 암컷이 수컷보다 더 길었으며, 수컷들은 몸의 길이, 코부터 총배설까지의 길이, 머리의 넓이, 꼬리부터 총배설까지의 길이, 꼬리의 넓이의 5개 요소에 있어서 모든 요소들이 서로 유의미한 상관을 보인 반면, 암컷에 있어서는 꼬리의 넓이를 제외한 모든 요소에서 의미 있는 상관을 보였다. 체외수정을 하는 한국산 도롱뇽의 성적인 행동은 암컷을 확인하는 단계,암컷을 유인하는 단계, 그리고 수정 단계로 구성되어진다. 안컷을 확인하는 단계는 암컷에게로 접근 행동 및 서로 코를 맞대는 행동으로 구성되며, 유인단계에서는 턱부비기, 꼬리치기, 냄새맡기, 파기의 네 가지의 과시 행동이 나타났다. 수정의 과정은 포집, 암컷으로부터 알주머니의 분리, 알의 수정, 수정 후 과시행동으로 구성되었다. 싸움 행동은 간단한 편으로, 공격하는 개체는 상대편의 위턱이나 뒷다리 부근을 주로 물었으며, 문 상태에서 자신의 머리를 2-3회 흔드는 행동을 보였다. 대부분의 경우에 있어서 개체의 크기에 상관없이 공격을 당한 개체는 공격한 개체로부터 재 빨리 회피를 하였으며, 승리를 한 개체는 빠른 꼬리치기 과시 행동을 보였다.