• 한국자원식물학회지
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• 제23권2호
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• pp.179-186
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• 2010

한라산에 자생하는 한국특산 모데미풀의 보전 및 복원을 위한 기초자료를 제공하기 위하여 생육지 특성을 연구하였다. 모데미풀의 자생지는 해발 1,075 m에 위치하고 경사는 $60-70^{\circ}$로 매우 가파른 암석지대로, 어리목 계곡의 북사면 일대에 소수의 개체가 불연속적이며 제한적으로 분포하였다. 조사는 모데미풀이 확인된 2개 지역과 분포하지 않는 인근지역을 조사하여 비교 하였다. 조사구 1은 교목층(35%)이 10-12 m로 형성되어 24종류의 식물종이 확인되었으며, 토양은 pH 5.59, 수분함량 9.39%, 유기탄소함량 8.22%, 유기물함량 14.17%로 조사되었다. 조사구 2는 굴피나무, 고로쇠나무로 형성된 수관(8-12 m, 40%)하에, 15종류의 식물종이 확인되었으며, 토양은 pH 5.07, 수분함량 4.99%, 유기탄소함량 5.34%, 유기물함량 9.21%로 조사되었다. 대조구의 경우는 서어나무 교목층(10 m, 10%)하에, 14종류의 식물종이 확인되었으며, 토양은 pH 5.27, 수분함량 6.23%, 유기탄소함량 4.74%, 유기물함량 8.17%로 조사되었다. 본 연구에서 확인된 위협 요인으로는 다른 종과 생육지 경쟁에서의 도태, 매우 가파른 자생지 구조 등의 자연적인 요소와 계곡 정비와 같은 인위적인 요소로 판단되었으며, 보전을 위한 현지 내외 보호가 필요할 것으로 판단된다.

• 한국토양비료학회지
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• 제44권1호
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• pp.48-52
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• 2011

The effect of soil water content on the transformation potential of N compounds derived from hydrolysis of urea applied in a reclaimed tidal soils which was saline-sodic was observed to evaluate nitrification rates of urea. Soil samples were collected from Moonpo series at the newly reclaimed area in Saemanguem. For the transformation potential of N compounds from urea (46% N), newly reclaimed tidal soils (RS) were amended with urea at the rates of 0, 10, and 20 kg $10a^{-1}$. With leachate obtained from the incubated RS in a leaching tube at $25^{\circ}C$, urea hydrolysis and nitrification were measured for a total of 30days. The cumulative amounts of $NO_3{^-}$-N in each of the four soils treated with urea was linear with time of incubation. Results showed that increase in pH occurred with increasing application rate of urea and volumetric water content due to hydrolysis of urea. The total N in the RS was decreased with incubation time, indicating that rates of urea hydrolysis was influenced by soil moisture conditions. Also, the cumulative amount of nitrate in RS gradually increased with increase in time of incubation.

• 미생물학회지
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• 제12권4호
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• pp.153-158
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• 1974

Around and in the area of Wolgot-Muon, Gimpo-Gun, Kyunggi province, I examined total bacteria, general Pseudomonas spp., fluorescent Pseudomonas spp., in soil layers and also in different kinds of soil of respective diseased, uncultivated, and healthy areas, and found the followings. 1. In the diseased and uncultivated areas, the content of moisture and silt was greater than in the healthy area. 2. Contrary to the above, the healthy area contained a greater amount of inorganic elements such as $P_2O_5$, K, Ca and of soil particle such as Cs and Fs. The degree of pH and content of Mg were even in three types of soils. 3. Total bacteria were found in abundance in the healthy soil. It was observed that in all types of areas, bacteria reside in abundance in the rhizosphere, i.e., 10-15 cm layers and that the closer the surface, the greater the numbers of the bacteria. 4. General Pseudomonas spp. were also found to the greater in number on the surface of the soil, especially so in the rhizosphere, with the numbers decreasing as the soil layers increase. Numbers of this bacteria in all types of area were nearly uniform. 5. A great number of fluorescent Pseudomonas spp. were found in the diseased area, especially so in the rhizosphere.

• 한국안전학회지
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• 제14권2호
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• pp.116-121
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• 1999

When plate anchors are embedded in soft clay, they may undergo a deformation under the pressure of sustained load. The critical depth at which the transition from a shallow to a deep anchor takes place depends on the properties of soil. Laboratory model tests were performed for the short-term net ultimate uplift capacity of a circular anchors with respect to various embedment depths and moisture content in saturated kaolinite. The tests have been conducted with the anchor at two different moisture contents. Based on the model test results, empirical relationships between the net load, rate of strain, and time have been developed. In creep tests of kaolinite for load versus ultimate uplift capacity, the displacement of plate anchors rapidly increases during the primary stage but thereafter becomes constant over a period of time.

• Journal of Biosystems Engineering
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• 제23권3호
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• pp.271-276
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• 1998

A gripper mechanical design using a pneumatic system was developed to successfully grip, hold, and release a seedling plug for transplanting it. The gripper comprised of two air cylinders and shovel-type fingers. The gripper can grasp and hold a seedling by sliding the two fingers attached to the two separate air-cylinders, mounted at an angle of 15$^{\circ}$ When releasing a plug, retraction of the fingers gives a seedling little attachment to the gripper. To prevent seedling from attaching to the fingers, press-plates were attached to the end of the gipper. Transplanting performance of the developed gripper was tested with cucumber seedlings at different soil moisture contents. Overall transplanting performance of developed gipper was higher than the performance of the previously developed gripper. Best transplanting result was achieved at medium level of soil moisture content.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.373-382
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• 1993

A non-contact sensor for detecting distance from field surface to a predetermined location of a tractor will be useful to control precise height of implements such as tillage machinery, mowers etc.. An optical and an ultrasonic sensors were designed and fabricated . The indoor and outdoor experiments were conducted to obtain the static and dynamic characteristics of the two sensors at several moisture levels of four soils and on the soil surface with a designed shape. The results revealed that the optical sensor is unsuitable for soils with high moisture content but showed better detecting accuracy on the irregularity of soil surface.

• Journal of Plant Biology
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• 제16권3_4호
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• pp.1-6
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• 1973

The distribution of plant communities along the Bukhan Riverside in Chun-seong was studied by means of the methods fo Curtis and Pattern. The communities were arranged in a single-dimensioned ordination on the basis of the importance values of the persistent species. Leading dominant species, form the 'low' level to the 'high' levels of the ordination gradient, were Phalaris arundinacea, Salix gilgiana, Artemisia feddei, Zoysia japonica, Pennisetum japonicum, and Arundinella hirta. These species from a continuum from the river to the dry grassland depending upon available soil-moisture. Standing crops in terms of dry weight and the nitrogen content of the above-ground parts of these species showed a good relationship with gradients of available soil-moisture.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2010년도 정기 학술발표대회
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• pp.114.2-114.2
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• 2010

지표면 근처에서의 토양수분 함유량은 지표면과 대기 사이의 물과 에너지의 순환에 큰 영향을 주기 때문에 수문 생태학적 과정에서 매우 중요한 역할을 하고 있다. Soil Moisture Experiment 2004(SMEX04) 프로젝트는 넓은 공간에서의 토양수분의 분포를 알아내기 위해 이용하고 있는 Advanced Microwave Scanning Radiometer - Earth Observing System(AMSR-E) 위성 관측 이미지로 얻은 결과를 현장 검증하기 위해 미국 Arizona 주에 2004년 6-9월에 걸쳐 추진되었으며, 프로젝트를 통해 얻은 토양수분 데이터를 이용하여 건조지역에서의 토양수분의 공간 변동성을 통계적 방법으로 분석하였다.

• 농약과학회지
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• 제4권4호
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• pp.61-65
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• 2000

배추 무사마귀병 뿌리혹의 부패에 미치는 온도 토양수분 담수, 토양미생물의 영향을 실내에서 조사하였다. 뿌리혹의 완전부패까지 소요일수는 온도가 높을수록 빨라서 $32^{\circ}C$ 이상에서는 3일, $16{\sim}20^{\circ}C$에서는 12일, $8^{\circ}C$에서는 28일이 소요되었다. 토양수분이 높을수록 뿌리혹의 부패도 빨라서 포화수분의 경우 $32^{\circ}C$에서는 3일, $24^{\circ}C$에서는 8일이 소요되었고, $32^{\circ}C$에서는 토양수분의 영향이 $24^{\circ}C$에서 보다 낮았다. 담수에 의한 뿌리혹의 부패촉진효과는 $32^{\circ}C$에서는 나타나지 않았으나, $24^{\circ}C$와 $12^{\circ}C$에서는 높았다. 뿌리혹의 부패에 대한 외부 토앙미생물의 영향은 나타나지 않았다. 뿌리혹의 부패에 가장 큰 영향을 미치는 요인은 온도였으며 온도가 비교적 낮을수록 다른 환경요인에 의해 영향을 많이 받는 것으로 나타났다. 뿌리혹내 휴면포자는 뿌리혹의 부패 후 시간이 경과할수록 그 성숙도가 증가하였으며, 신선한 뿌리혹은 부패한 혹에 비하여 휴면포자의 밀도도 낮았고 그 성숙도도 저조하였다. 완전히 부패한 뿌리혹내 휴면포자의 밀도는 1 g 조직당 $6.5{\times}10^{6}$개였으며 성숙 휴면포자율도 95% 이상에 달하였다.

• 한국토양비료학회지
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• 제46권4호
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• pp.281-287
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• 2013

Due to its high salt content and poor physical properties in reclaimed tidal lands, it is important to ameliorate soil physical properties to improve the efficiency of desalination. The objective of this study was to evaluate the changes of soil properties at Saemangeum reclaimed tidal saline soil with various soil amendments. Field experiment was conducted at Saemangeum reclaimed tidal land in Korea and the dominant soil series was Munpo series (coarse loamy, mixed, nonacid, Mesic, Typic, Fluvaquents). Woodchips, crushed-stone, oyster shell, coal bottom ash, and rice hull were added as soil amendments and mixed into surface soil to improve soil physical properties. There was large variability in soil hardness, but oyster shell treatment was significantly lower soil hardness at surface layer. Soil hardness was not significantly different below 15 cm depth. Infiltration rate was also significantly greater at oyster shell treatment. This may be due to the leaching of Ca ions from oyster shell and improved soil properties. However, there was no statistical significant difference of the soil bulk density, moisture content, and porosity. Improved physical properties increased desalinization rate in soil and retarded the resalinization rate when evapotranspiration rate was high. Although soil salinity was significantly decreased with oyster shell amendment, soil pH was increased that should be made up as a soil amendment. Our results indicated that oyster shell application increased infiltration rate and improved soil hardness, and thus oyster shell could be used to improve soil salinity level at Saemangeum reclaimed tidal saline soil.