• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.60-65
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• 2016

The main objective of this research was to estimate the total mass of nitrogen discharged from various sources in paddy field area of South Korea in 2010 and 2013. Input and output budgets for nitrogen were estimated by mass balance approach. The mass balance approach reduces the effect of flow variations, and the large scale approach minimizes local effects, resulting in easier and faster establishment of strategy for nonpoint pollution problems. Nitrogen inputs were chemical fertilizer, compost, atmospheric deposition, biological fixation, and agricultural water, while crop uptake, denitrification, volatilization, and infiltration were nitrogen outputs. The estimated total nitrogen inputs for paddy field in South Korea were $266,211ton\;yr^{-1}$, $260,729ton\;yr^{-1}$, while those of total nitrogen outputs were $168,463ton\;yr^{-1}$, $164,994ton\;yr^{-1}$ in 2010 and 2013, respectively. Annual amounts of potential nitrogen outflow from paddy field were $97,748ton\;yr^{-1}$, $95,735ton\;yr^{-1}$ in 2010 and 2013. Also, annual rate of potential nitrogen outflow were 36.7%, 36.7% in 2010 and 2013, respectively.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.4
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• pp.352-359
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• 2009

KEPRI is developing a Korean type coal-gasification system and the scale is 20 ton/day. Prior to this pilot plant, a 1 ton/day class gasification system will be used for pre-testing of several coal types. This paper introduces the configuration and design conditions of this 1 ton/day class system, presenting the gas/coal ratio, oxygen/coal ratio, cold gas efficiency, CFD analysis of gasifier, and others. The existing combustion furnace for residual oil was retrofitted as a coal gasifier and a vertical and down-flow type burner was manufactured. Ash removal is carried out through a water quencher and a scrubber following the quencher, and the sulfur is removed by adsorption in the activated carbon tower. The gas produced from the gasifier is burned at the flare stack. In this paper, the results of design conditions and initial operation conditions of I ton/day gasification system are compared together.

• Journal of Ecology and Environment
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• v.32 no.1
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• pp.27-31
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• 2009

Organic carbon (OC) distribution in 32-year-old pitch pine plantation at Mt. Hotae in Kongju, Korea, was studied from August 2007 to July 2008. In order to investigate the OC distribution, OC in plant biomass, litterfall, litter layer on forest floor, and soil within 50cm depth were estimated. The density of P. rigida plantation was 3,200 trees/ha, average DBH was $18.7{\pm}5.53cm$ and average tree height was $11.1{\pm}1.85m$. Organic carbon stored in plant biomass, litterlayer on forest floor and soil in 2008 was 89.46 ton C/ha (46.09%), 4.32 ton C/ha (2.23%) and 100.32 ton C $ha^{-1}$ 50cm-$depth^{-1}$ (51.68%), respectively. Amount of OC returned to forest floor via litterfall was 2.21 ton C $ha^{-1}\;yr^{-1}$. Total amount of OC stored in this P. rigida plantation was 194.1 ton C/ha. Net increase of OC in above- and below-ground biomass in this pitch pine plantation was 4.82 ton C $ha^{-1}\;yr^{-1}$.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2010.06a
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• pp.167-169
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• 2010

본 연구는 산림내 산불잠재위험성 평가를 위해 충남지역을 대상으로 소나무림과 참나무림의 층위별 연소물량의 분포를 추정하기 위함이다. 각 임분의 층위별 연소물량을 파악하기 위해 $10m{\times}10m$ 방형구내의 상층(수고 8m 이상), 중층(8m 이하), 관목층, 지표층(초본, 낙엽, 낙지)을 대상으로 총 36개소를 조사하고 단위면적당(ha) 바이오매스량(연소물량)을 추정하였다. 혼효림의 층위별 연소물량은 소나무림과 참나무림에서 얻어진 결과를 1/2씩 합산하여 추정하였다. 분석결과 충남지역에서 추정된 연소물량은 상층 60~190 ton/ha, 중층 0.5~16 ton/ha, 관목층 0.06~1.9 ton/ha, 초본층 0.04~1.2 ton/ha, 낙엽 1~18 ton/ha, 낙지 0.3~7 ton/ha의 분포를 보이는 것으로 나타났다. 향후 본 연구결과에서 얻어진 층위별 연소물량의 공간분포를 이용하여 산림내 산불잠재위험성을 평가할 계획이다.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2008.12a
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• pp.133-138
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• 2008

1) 두과작물의 생초수량과 건물수량은 작물별로 차이가 컸다. 지상부는 Red clover가 생초수량 38.6 ton/ha, 건물수량 7.86 ton/ha로 가장 많았으며, 지하부 또한 Red clover가 생초수량 30 ton/ha, 건물수량 6.2 ton/ha로 가장 많았다. 2) CP 수량 및 TDN 수량은 Red clover가 각각 1 ton/ha, 4.6 ton/ha로 유의하게 높았으며 NDF와 ADF는 수확시기가 늦을수록 높은 경향을 나타내서 Galega와 Cicer milk vetch가 가장 높았다. 또한 상대사료가치(RFV)는 공시품종 대부분이 100 이상을 나타내어 사료가치가 우수하였으며 Yellow blossom sweet clover, Crimson clover, Hairy vetch 등은 151% 이상으로 1등급에 속하였다. 3) 가축사육능력은 $K_{cp}$(2.18 head/ha/yr) > $K_{TDN}$(1.25 head/ha/yr) >K(0.04 head/ha/yr) 순으로 높게 나타났으나 이는 상당히 낮은 수준이었으며 이는 두과작물의 적은 수량으로 인한 결과라 판단되어진다. 4) 두과작물과 화본과작물 혼파시 $K_{cp}$ $K_{TDN}$ 모두 두과작물 평균 2.18, 1.25보다 높았다. 또한 Rye-Galega 8:2 비율, Rye-Winter pea 7:3 비율에서 건물수량, $K_{cp}$ $K_{TDN}$이 화본과 단파시보다 증가하여 혼파효과가 인정되었다. 특히 건물수량과 $K_{TDN}$ 관계에서 혼파 비율에 따라 건물수량에 큰 차이를 보이지 않은 반면 $K_{TDN}$은 모든 비율에서 증가하여 사료가치가 상승하였다.

• Journal of Ocean Engineering and Technology
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• v.22 no.6
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• pp.20-26
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• 2008

In this paper, in order to set up the management system of water quality environment in Gwangyang Bay, the cluster analysis of water quality environment, the estimation of inflowing pollutant loads and residence time of pollutants in this bay was carried out. The Gwangyang Bay was divided into eight sea areas by cluster analysis and spatio-temporal change of water quality. The river discharges in the Bay were calculated about $11,681{\times}103m^3/day$ from the numerical simulation by Tank model. In addition, inflowing pollutant loads of COD, SS, TN, TP, DIN and DIP in Gwangyang Bay were estimated at 398 ton-COD/day, 2,846 ton-SS/day, 195 ton-TN/day, 5 ton-TP/day, 126 ton-DIN/day and 3 ton-DIP/day, respectively. Moreover, residence times of COD, TN and TP in the Bay was estimated at 6 days-COD, 20 days-TN and 195 days-TP, respectively in the dry season, and 3 days-COD, 6 days-TN and 21 days- TP, respectively, in the flood season. The central part of Gwangyang Bay (Region IV) has the longest residence time of overall pollutants.

• Journal of Biosystems Engineering
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• v.19 no.4
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• pp.329-342
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• 1994

In order to reduce the production cost and improve the quality of dairy feed, several dairy feed mill models suitable for Korean farm size were developed. 6 TMR models were developed for the 1000, 600, 200 head of dairy cattle, and evaluated for capital investments and production costs to suggest the best model. Followings are summary of this study : 1. TMR terminal models were designed that dairy production capacity of TMR1000 models are 40 ton/day, TMR600 model is 20 ton/day and TMR200 models are 10 ton/day. Also, they can be extended their capacity up to twice. 2. Capital investment of TMR terminal models is 145 million won for TMR200-1,205 million won for TMR600 and 609 million won for TMR1000-3 model. 3. The bigger TMR terminal model has the more advantage in production cost. The best model for 1000 head of dairy cattle farm was TMR1000-3 with 10,849 won/ton of production cost, TMR600 for 600 head of dairy cattle farm with 13,829 won/ton, TMR200-1 for 200 head of dairy cattle farm with 16,943 won/ton of production cost, so feed production cost for the 200 head farm was 50% higher than 1,000 head size farm.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.3
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• pp.1719-1723
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• 1969

In this country, farmers lay out furrows in the direction which is considered by their own judgement to be convenient for cultivation without paying much attention for soil erosion. The direction of furrow has considerable effects on soil and water losses. In this experiment, it is intedned to observe the differences of soil and water losses in different directions of furrows of sloped fields so that the results thus obtained could be informed to farmers who should be careful in determining furrow direction for soil erosion control. Some the major experimental results are summarized as follows: The direction of furrows did not affect so much on the runoffs in a gentle slope, as the runoff is 509 ton/10a in the contouring plot, $51^{\circ}$/ton/10a in the 45-degree plot, and 560 ton/10a in the up-and-down hill plot. The contouring plot among the three plots had best effect on soil conservation, as the soil losses are 5.8 ton/10a in the contouring plot, 9.3 ton/10a in the 45 degree plot, and 10.2 ton/10a in the up-and-down hill plot.

• Journal of Environmental Impact Assessment
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• v.8 no.1
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• pp.41-49
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• 1999

This study was carried out to estimate the runoff loading characteristics of the non-point source pollutions in the Youngsan river basins by the method of land-use types and rainfall. The lysimeter test, rainfall and stream flowmeter measurement were performed to develop the pollutant loading unit discharged from the non-point sources. As the non-point sources, the unit pollutant discharge rates were different from the land-use types such as paddy field, upland, forest, housing site and others. The pollutant loading units classified by land-use types in the Youngsan river basins are as follows: The total BOD loading rate is 15.3 ton/day and the housing site is discharged 50.6%, the total T-N loading rate is 6.0 ton/day and the paddy field and upland is discharged 77.6%, and the total T-P loading rate is 0.39 ton/day and the paddy field and upland is discharged 81.2%. The pollutant loadings by rainfall in the Youngsan river basins are about 7,425 ton/year of BOD, 324 ton/year of T-N and 118 ton/year of T-P, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.4
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• pp.338-342
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• 1996

Fodder rye(cv. Coolgrazer) was cultivated on paddy soils under different application rates of animal manures (CM=cow manures mixed with sawdust, SM=swine manure mixed with sawdust) during 1994-1995. Rice crop (CV. Geumo) was transplanted in the same plots after fodder rye. The effects of cattle manure application on the yield performance of rye and their influence to growth, yields and quality of rice were evaluated. Fodder rye produced larger plant growth and higher silage yield in the cattle manure application than in the chemical feltilizer (CF). Dry matter yields of rye silage were 3.08 ton(CF), 4.23 ton(CM) and 6.03 ton/ha(SM), respedively. Under heavy application of cattle manures plant height, number of tillers and grains per panicle were increased, but 1,000 grains weight and total yields of rice were decreased. Yields of brown rice were 5.20 ton(CF), 5.15 ton (CM) and 4.95 ton/ha(SM), respectively. Higher concentration of amylose was found in the heavy application of cattle manures. Amylose contents of rice were 16.8%(CF), 19.1%(CM) and 19.4%(SM).