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A Study on the Leakage Protection with Polypropylene Mat in Irrigation Canal (Polypropylene Mat에 의(依)한 용수로(用水路)의 누수방지(漏水防止)에 관(關)한 연구(硏究))

  • Kang, Sin-Up;Kang, Yea-Mook;Cho, Seung-Seup
    • Korean Journal of Agricultural Science
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    • v.6 no.2
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    • pp.166-184
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    • 1979
  • In order to prevent the water loss in the irrigation canal constructed on the sandy gravel layer or on the other highly permeable ground layer, lining has been practiced. Many studies have been done so far on the lining method to prevent the water loss in the irrigation canal and recently studies on the lining with plastic film or polyethylene film were also reported. However, the plastic film or polyethylene film has low strength and is liable to break, and water loss from pin hole caused by contacting with sand or gravel is highly predicted. This study was then conducted to find proper lining and buring method in canal construction of polypropylene mat after coated with vinyl, as one way to overcome the shortcoming frequently observed when plastic or usual polyehtylene film were used. Eventhough rather longer periods of experiments are needed to attain reliable and accurate results on the variation of durability, the durability of asphalt coated area, or on the damage due to freeze after burial or exposure of polypropylene mat, the experiemental results obtained during one year of period are summarized as follows: 1. The curvature at the area between canal bottom and side slope had increased stability and saved consruction cost. The relationship among the variation of curvature, the reduction of polypropylene mat and the reduced amount of soil cutting at each side slope was presented in Fig. 7 through 9. 2. The depth of covering material to protect polypropylene mat was desired to be over 30cm, considering the water depth, side slope, canal cleaning practices, traffic, or back pressure of irrigation period. 3. In order to increase the canal stability and to prevent slope erosion, sandy soil was required, to be placed under ground, and coarse gravel should cover the surface area of canal. 4. The studies on the stability of side slope in the canal should consider the passive area on the bottom and the slope should be about 1 to 2, considering the slope stability, allowable velocity and tractive force. 5. When compared with earth lining, the lining with polypropylene mat coated with vinyl was responsible to save 28% and 37% of canal lining cost, when the soil carrying distances were 500 and 700m. respectively. 6. The water interception was almost completely attained when the polypropylene mat coated with vinyl was used for lining. But further studies were assumed to be necessary for the use of asphalt since the strength of polypropylene mat connected with asphalt will vary with duration.

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Simulation of Soil Moisture in Gyeongan-cheon Watershed Using WEP Model (WEP 모형을 이용한 경안천 토양수분 모의)

  • Noh, Seong-Jin;Kim, Hyeon-Jun;Kim, Cheol-Gyeom;Jang, Cheol-Hee
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.720-725
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    • 2006
  • 토양수분은 식물의 생장 및 가용수자원 산정 등에 있어서 중요한 요소로서 토양층 상부의 수 m내에 존재하는 수분의 양을 일컫는다. 토양수분과 토양수분의 공간적 시간적 특징들은 증발, 침투, 지하수 재충전, 토양침식, 식생 분포 등을 지배하는 중요한 요소이다. 강우 등으로 인한 지면과 지표하에서의 순간적인 포화공간의 형성 및 유출의 생성 등을 포함하는 과정과 증발산 등은 모두 비포화대(vadose zone) 혹은 토양층에서의 토양수분의 함량에 크게 의존하게 된다(이가영 등(2005)). 분포형 수문모형은 유역을 격자단위로 세분화하여 매개변수를 부여하고, 증발산, 침투, 지표면유출, 중간유출, 지하수유출, 하도 흐름 등 여러 가지 수문요소를 해석하는 종합적인 수문모형이다. 지표면에 내린 강우가 증발, 침투, 유출될 지는 토양수분의 함량에 크게 의존하게 되며, 따라서 토양수분에 대한 적절한 모의가 분포형 수문모형의 정확도를 좌우하는 핵심이라 할 수 있다. 본 연구에서는 분포형 수문모형인 WEP 모형을 경안천 유역(유역면적: $575km^2$, 유로연장: 49.3㎞)에 적용하여 토양수분의 시공간분포를 모의하였다. 지점별 토양수분 모의결과, 토양 매개변수의 최대, 최소값 내에서 적절히 모의됨을 확인하였으나, 관측값이 없어 실질적으로 타당한지 여부는 검증하지 못하였다. 토양수분비율, 연간 증발산량, 지표면 유출량 공간분포를 비교한 결과, 토양수분비율이 연간 증발산량 모의에 직접적인 영향을 주는 것을 확인할 수 있었다. 일부격자에서는 토양수분이 지나치게 높게 모의되었는데, 지하수위와 관련있는 것으로 보이며, 구축된 자료가 부족한 지하대수층에 대한 정보부족이 토양수분 계산에도 영향을 준 것으로 보인다. 본 연구는 WEP 모형의 토양수분 해석능력에 대한 시험적용에 그 의의가 있으며, 향후 토양 및 지표하 매개변수 정보가 충분히 갖추어지고, 토양수분 관측결과 있는 대상유역에 대한 적용이 요구된다.-Moment 방법에 의해 추정된 매개변수를 사용한 Power 분포를 적용하였으며 이들 분포의 적합도를 PPCC Test를 사용하여 평가해봄으로써 낙동강 유역에서의 저수시의 유출량 추정에 대한 Power 분포의 적용성을 판단해 보았다. 뿐만 아니라 이와 관련된 수문요소기술을 확보할 수 있을 것이다.역의 물순환 과정을 보다 명확히 규명하고자 노력하였다.으로 추정되었다.면으로의 월류량을 산정하고 유입된 지표유량에 대해서 배수시스템에서의 흐름해석을 수행하였다. 그리고, 침수해석을 위해서는 2차원 침수해석을 위한 DEM기반 침수해석모형을 개발하였고, 건물의 영향을 고려할 수 있도록 구성하였다. 본 연구결과 지표류 유출 해석의 물리적 특성을 잘 반영하며, 도시지역의 복잡한 배수시스템 해석모형과 지표범람 모형을 통합한 모형 개발로 인해 더욱 정교한 도시지역에서의 홍수 범람 해석을 실시할 수 있을 것으로 판단된다. 본 모형의 개발로 침수상황의 시간별 진행과정을 분석함으로써 도시홍수에 대한 침수위험 지점 파악 및 주민대피지도 구축 등에 활용될 수 있을 것으로 판단된다. 있을 것으로 판단되었다.4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전략은 존재하므로 이러한 전략을 개발 및 활용할 수 있으며, 특히, 한국주식시장에 적합한 거래전략은 반전거래전략이고, 이 전략의 유용성은 투자자가 설정한 투자기간보다 더욱 긴 분석기간의 주식가격정보에 의하여 최대한 발휘될 수 있음을 확인하였다.(M1), 무역적자의

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The Effect of Dietary Protein and Calcium on Urinary Calcium in Young Men (식이단백질(食餌蛋白質)과 칼슘이 인체(人體)의 뇨중(尿中) 칼슘양에 미치는 영향(影響))

  • Koo, Jae-Ok
    • Journal of Nutrition and Health
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    • v.15 no.4
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    • pp.235-241
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    • 1982
  • Studies were carried out on seven young, adult caucasian males to determine the short-term effects of protein(animal or plant)and calcium intakes on the excretion of urinary calcium. The subjects were studied on a self-selected diet for a period of seven days. Mean daily protein and calcium intakes were $103{\pm}31\;g$ and $1237{\pm}594mg$ respectively. Variation among subjects in the mean urinary calcium excretion per 24 hour was from $121{\pm}40$ to $258{\pm}104mg$. When the protein intake of all aubjcts was divided in to four levels : low (x=53g), medium (87g), intermediate (117g) and high(153g), The mean urinary calcium was $179{\pm}53$, $189{\pm}73$, $184{\pm}55$ and $264{\pm}84mg$, respectively. Urinary calcium increased significantly with an increase in protein intake. The calcium excretion was seriously increased with the protein intake above the intermediate level. Animal protein intake was more closely related to urinary calcium excretion than plant protein. There was a significant difference in the urinary calcium excretion when calcium intakes increased from low(x=544mg) to interne-diate levels (1232 mg). However, the difference between intermediate and high levels (1834mg) was not significant. Urinary calcium was $169{\pm}46mg$ on the low calcium diet, $196{\pm}71mg$ on the medium, and $222{\pm}21mg$ on the intermediate calcium intake, Calcium excretion was more closely related to changes in protein intake than to changes in calcium intake. Some nutritional implications can be drawn from this research. Protein intakes above the intermediate level (117g) are not recommendable. An over intake of calcium, however, may not be a serious problem for the calcium balance.

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Movement of Cold Water Mass in the Northern East China Sea in Summer (하계 동중국해 북부 해역에서 저층 냉수괴의 거동)

  • Jang, Sung-Tae;Lee, Jae-Hak;Kim, Cheol-Ho;Jang, Chan-Joo;Jang, Young-Suk
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.16 no.1
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    • pp.1-13
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    • 2011
  • The Yellow Sea Cold Water (YSCW) is formed by cold and dry wind in the previous winter, and is known to spread southward along the central trough of the Yellow Sea in summer. Water characteristics of the YSCW and its movement in the northern East China Sea (ECS) are investigated by analyzing CTD (conductivity-Temperature-Depth) data collected from summertime hydrographic surveys between 2003 and 2009. By water mass analysis, we newly define the North Western Cold Water (NWCW) as a cold water mass observed in the study area. It is characterized by temperature below $13.2^{\circ}C$, salinity of 32.6~33.7 psu, and density (${\sigma}_t$) of 24.7~25.5. The NWCW appears to flow southward at about a speed less than 2 cm/s according to the geostrophic calculation. The newly defined NWCW shows an interannual variation in the range of temperature and occupied area, which is in close relation with the sea surface temperature (SST) over the Yellow Sea and the East China Sea in the previous winter season. The winter SST is determined by winter air temperature, which shows a high correlation with the winter-mean Arctic Oscillation (AO) index. The negative winter-mean AO causes the low winter SST over the Yellow Sea and the East China Sea, resulting in the summertime expansion and lower temperature of the NWCW in the study area. This study shows a dynamic relation among the winter-mean AO index, SST, and NWCW, which helps to predict the movement of NWCW in the northern ECS in summer.

Preservation of Fish Community by the Construction of the Tamjin Dam (탐진댐 건설에 따른 어류군집 보전방안)

  • Choi, Chung-Gil;Joh, Seong-Ju;Kim, Jong-Hae;Kim, Dong-Sup
    • Korean Journal of Ecology and Environment
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    • v.35 no.3 s.99
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    • pp.237-246
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    • 2002
  • Tamjin Dam is built in the upper reaches of the Tamjin River which flows through the Janghung-gun and Gangjin-gun of the Jeollanamdo, Korea. In order to map out a preservation strategy of the fish community from dam construction, We studied the distribution of fish distribution and changes of the habitat environment. we found 49 fish species inhabiting in the downstream and upstream of the Tamjin Dam. Among them, migratory fish were two species sweet smelt, Plecoglossus altivelis and freshwater eel, Anguilla japonica. The Coreoperca kawamebari which designated as a species to be protected by The Ministry of Environment of Korea was also observed. After the dam construction, reservoir would be filled with water and running water system will change to standing water system. Then the habitat and spawning space for mountain torrent fish will be reduced and the migration of migratory fish to upstream will be blocked. Through our study, we proposed several ways to protect fish community. In order to preserve the reduced habitat and spawning area of mountain torrent fish, a fishway has been diagnosed to be built in the shallow reservoir in the entrance of the upriver. The establishment of artificial spawning ground on the riverside has been recommended. In addition, We propose a creation of a shelter for fresh water eel, Anguilla japonica in areas where the depth of the water is about l0m by laying rocks. Since it is difficult for a spawning ground to be formed naturally in the reservoir due to the year-round changes in water level, We suggested a floating spawning facility using an artificial fixture. In the downstream of the dam, a waterway-style habitat and spawning ground in the river and increasing the diversity and abundance of fish fauna in the Tamjin River. A low-cost and highly efficient operational fishway has been recommended so that migratory fish such as Plecoglossus altivelis (sweetfish) can migrate from the lower reaches to the upper reaches of the river.

GMI Microwave Sea Surface Temperature Validation and Environmental Factors in the Seas around Korean Peninsula (한반도 주변해 GMI 마이크로파 해수면온도 검증과 환경적 요인)

  • Kim, Hee-Young;Park, Kyung-Ae;Kwak, Byeong-Dae;Joo, Hui-Tae;Lee, Joon-Soo
    • Journal of the Korean earth science society
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    • v.43 no.5
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    • pp.604-617
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    • 2022
  • Sea surface temperature (SST) is a key variable that can be used to understand ocean-atmosphere phenomena and predict climate change. Satellite microwave remote sensing enables the measurement of SST despite the presence of clouds and precipitation in the sensor path. Therefore, considering the high utilization of microwave SST, it is necessary to continuously verify its accuracy and analyze its error characteristics. In this study, the validation of the microwave global precision measurement (GPM)/GPM microwave imager (GMI) SST around the Northwest Pacific and Korean Peninsula was conducted using surface drifter temperature data for approximately eight years from March 2014 to December 2021. The GMI SST showed a bias of 0.09K and an average root mean square error of 0.97K compared to the actual SST, which was slightly higher than that observed in previous studies. In addition, the error characteristics of the GMI SST were related to environmental factors, such as latitude, distance from the coast, sea wind, and water vapor volume. Errors tended to increase in areas close to coastal areas within 300 km of land and in high-latitude areas. In addition, relatively high errors were found in the range of weak wind speeds (<6 m s-1) during the day and strong wind speeds (>10 m s-1) at night. Atmospheric water vapor contributed to high SST differences in very low ranges of <30 mm and in very high ranges of >60 mm. These errors are consistent with those observed in previous studies, in which GMI data were less accurate at low SST and were estimated to be due to differences in land and ocean radiation, wind-induced changes in sea surface roughness, and absorption of water vapor into the microwave atmosphere. These results suggest that the characteristics of the GMI SST differences should be clarified for more extensive use of microwave satellite SST calculations in the seas around the Korean Peninsula, including a part of the Northwest Pacific.

The effect of restricted fluid intakes in the first week of life on the risk of bronchopulmonary dysplasia and patent ductus arteriosus in very low birth weight infants (극소저출생체중아에서 생후 첫 주의 제한적 수액투여가 기관지폐이형성증과 동맥관개존증 발생에 미치는 영향)

  • Koo, Hoe Kyoung;Choi, Eun Na;Namgung, Ran;Park, Min Soo;Park, Kook In;Lee, Chul
    • Clinical and Experimental Pediatrics
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    • v.50 no.6
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    • pp.536-542
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    • 2007
  • Purpose : We investigated the effects of restricted fluid in the first 7 days of life on the risk of bronchopulmonary dysplasia (BPD) or patent ductus arteriosus (PDA) in very low birth weight (VLBW) infants. Methods : Eighty three VLBW infants who lived more than 28 days were selected. The amount of daily maintenance fluid was determined by calculation of insensible water loss (IWL) and urine output (UO). Seventy to 80 percent of calculated amount was given to the ventilated infants. Subjects were grouped into low (<25th%), moderate (25-75th%), and high (>75th%) fluid groups for the first 24 hours, 3 days and 7 days. Chi square tests analyzed proportions of subjects with or without morbidities across fluid groups. Multivariate logistic regression was used to analyze the effect of fluid intake on BPD or PDA, controlling for factors that are significantly associated with BPD or PDA by univariate analysis. Results : Rates of BPD and PDA were not significantly associated with fluid groups on each time period. The result was the same after controlling for factors that are significantly associated with BPD or PDA by univariate analysis. For the first 3 and 7 days, fluid intakes were positively related with maximal weight loss, urine output and mechanical ventilation duration. Conclusion : In VLBW infants, when given based on needs reflected from IWL and UO versus intake, relatively low fluid intakes in the first week of life do not decrease the risk of BPD or PDA, and vice versa. We suggest that calculation of daily fluid based on IWL and UO is appropriate for VLBW infants.

Multilateral Approach to forming Air Logistics Hub on North East Asia Region (동북아 항공물류허브을 구축하기 위한 다자적 접근방안)

  • Hong, Seock-Jin
    • The Korean Journal of Air & Space Law and Policy
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    • v.19 no.2
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    • pp.97-136
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    • 2004
  • The Northeast Asian air cargo market has expanded tremendously as a result of the opening up of the Chinese market. The importance of the Asia-Pacific region in the global air transport has also increased. The exchange of human and material resources, services, and information in Northeast Asia, which is expected to increase in the near future, requires that the airlines operating within this region adopt a more liberalized approach. This paper introduced alternatives which can be applied to the Northeast Asian airlines industry so as to bring about the integration of regional air transport: First, this paper found a need for individual Northeast Asian nations to alter their policies towards the airlines industry. Second, each country should further liberalize their respective domestic air transport. Third, there is a need for freer air service agreements to be signed between the nations of Northeast Asia. Fourth, the strategic alliances between the airlines operating in Northeast Asia should be further strengthened. Fifth, this liberalization process should be carried out in an incremental manner, beginning with more competitive airports and routes, or with less-in-demand routes. Sixth, there is a need for a shuttle system to be put into place between the main airports in China, Korea, and Japan. Seventh, these three nations jointly develop aviation safety and security systems that are in accordance with international standards. Eighth, the liberalization process of the aviation industry should be undertaken in conjunction with other related fields. Ninth, organizations linking together civil aviation organization in the Asia-Pacific area should be formed, as should each government linking together. By doing so, these countries will be able to establish regular venues through which to exchange opinions on the integration and liberalization of the air cargo market so as to induce the gradual liberalization of the actual market. The liberalization of the air transport in Northeast Asia will prove to be a daunting task in the short term. However, if the Chinese airlines continue to exhibit continuous growth and Japanese airlines are able to complete their move towards a low-cost structure, this process could be completed earlier than expected. Over the last twenty five years the air transport has undergone tremendous changes. The most important factor behind these changes has been the increased liberalization of the market. As a result, rates have decreased while demand has increased. This has resulted in turning the air transport industry, which was long perceived as an industry in decline, into a high-growth industry. The only method of increasing regional exchanges in the air transport is to pursue further liberalization. The country which implements this liberalization process at the earliest date may very well emerge as a leading force within the air transport industry.

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Proteomic Analysis and Growth Responses of Rice with Different Levels of Titanium Dioxide and UV-B (이산화티탄과 UV-B 수준에 따른 벼 생육과 프로테옴 해석)

  • Hong, Seung-Chang;Shin, Pyung-Gyun;Chang, An-Cheol;Lee, Ki-Sang;Lee, Chul-Won;Woo, Sun-Hee
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.52 no.1
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    • pp.69-80
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    • 2007
  • Among the photoactive semiconductors such as $TiO_2,\;ZnO,\;Fe_2O_3,\;WO_3,\;and\;CdSe,\;TiO_2$ is the most widely used as photocatalyst in different media, because of its lack of toxicity and stability. In this study, the effects of titanium dioxide were investigated to obtain the information of physiological change in rice plant. Light-adapted Chlorophyll flourescence index decreased and relative electron transport rate of rice leaves was activated by titanium dioxide under $2,400\;{\mu}mol\;m^{-2}\;s^{-1}$ PAR (Photosynthetic active radiation). Relative electron transport rate of rice leaf treated with titanium dioxide 10 ppm was high in order of $2,400\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR,\;2,200\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR,\;450\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR$ and titanium dioxide 10 ppm (45.1%), control (32.4%), diuron 10 ppm (15.3%) under $2,400\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR$. Titanium dioxide increased photosynthesis of the rice leaf under $13.6\;KJ\;m^{-2}\;day^{-1}$ UV-B only. With titanium dioxide 20 ppm, reduced UV-B ($0.15\;KJ\;m^{-2}\;day^{-1}$) intensity changed the induction of proteins and twenty-five proteins were identified. Among them, seventy proteins were up-regulated, four proteins were down-regulated and four proteins were newly synthesized. Function of these proteins was related to photosynthesis (52%), carbohydrate metabolism (4%), stress/defense (8%), secondary metabolism (4%), energy/electron transport (4%), and miscellaneous (28%).

Studies on Amelioration of Soil Physico-Chemical Properties and Rice Yield in Sandy Tidal Saline Paddy Soil (사질(砂質) 염해답(鹽害畓)에서 개량제(改良劑) 시용(施用)이 토양(土壤)의 물리화학성(物理化學性) 변화(變化)와 수도수량(水稻收量)에 미친 영향(影響))

  • Yoo, Chul-Hyun;Kim, Jong-Gu;Choi, Song-Yeol;Cho, Guk-Hyun;Yoo, Sug-Jong;So, Jae-Dong;Rhee, Gyeong-Soo
    • Korean Journal of Soil Science and Fertilizer
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    • v.26 no.4
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    • pp.241-248
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    • 1993
  • An experiment was conducted in 1990~1991 to study the effects of various soil amelioration on the soil productivity and machine workability at tidal land paddy field of Kyewhado Substation, Homam Crop Experiment Station. The soil, Munpo Series(fine sandy loam, Typic Fluvaquents) was treated with gipsum, rice straw, rice straw compost and foreign soil(at 20cm depth) after deep ploughing. The results are surmerized as follows. 1. Sand and clay were slightly increased, while silt was slightly decreased in the rice straw and compost plots. The soil texture was changed from loam to sand loam by the addition of foreign soil 2. Soil bulk density and porosity was decreased in the rice straw, compost and foreign soil addition plots. 3. Cone penetration resistance was $12.5kg/cm^2$ at 10cm of soil depth before experiment and $12.5kg/cm^2$ at 20cm of soil depth after experiment except control, and the root zone was expended down to 20cm. 4. Soil salt content before experiment was 0.46 and 0.48% for surface soil(10cm) and subsoil(20cm), respectively ; The salt content of ameliorated plot was 0.26~0.32% and 0.16~0.31%, respectively, indicating good leaching of soil salt by the soil improvements. 5. The yields of rice in different treatments were in the order of the foreign soil addition > compost > gypsum > rice straw > control.

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