• 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 Geotechnical Society
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• v.20 no.3
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• pp.119-128
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• 2004

Environmental impact of waste tires as gound-reinforcing material is studied. Analysis for chemical compounds and toxic effect were performed on effluents from twelve lysimeters in which waste tires were mixed with sand and three initially different environmental solutions of acidic, neutral, and basic circulated through the mixture. The test results of effluents collected from the lysimeters provided that the contaminant concentrations were lower than those of Korean drinking water standards for all the selected and tested metal elements. While iron concentration increased slightly with the exposure period, other metal concentrations decreased with the number of circulation times. From the comparison with previous investigations, the contaminant concentration decreased with the increase of tire size, i.e. increases with the increase of the exposed surface of tire metals. From the toxicity tests, no deteriorative effect was observed and it could be concluded that waste tires are not biologically hostile materials.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.67-70
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• 2012

현재 국내외에서는 양질의 증발산을 관측하여 활용하기 위해 증발접시 (evaporation pan), 침루계 (lysimeter) 등을 이용하여 실측하거나 Flux Tower에서 Eddy covariance technique, Bowen ratio method 등을 이용하여 경험적으로 산정하고 있다. 이러한 방법으로 산정되는 증발산은 크게 두 분류로 나눌 수 있다. 일반적인 기후 상태에서 유역의 토양이 증발산에 방해를 받지 않을 정도로 충분히 물을 포함하고 있고, 식생이 조밀한 상태에서의 증발산량을 의미하는 잠재 증발산과 실제 산정치인 실제 증발산으로 나눌 수 있다 (Thornthwait, 1939). 본 연구에서는 유역의 잠재 증발산을 산정하여 실제 증발산과 비교를 통해 적용성을 확인하고자 한다. 잠재 증발산을 산정하는 방법은 Moderate Resolution Imaging Spectroradiometer (MODIS) 인공위성 데이터를 이용한 원격탐사 기술을 적용하여 산정한다. 원격탐사 기술은 지상 관측의 단점을 보완한 것으로써, 날씨, 인간 활동 등 주변 외부 환경의 영향에 민감하게 반응하여 공간적인 분포 현황을 파악하는 것이 어려운 지상 관측의 한계점을 대체하기 위한 방법이다. 이들 방법으로는 가장 널리 쓰이는 Penman-Monteith (Penman, 1948; Monteith, 1965), 일별 최대, 최저, 평균 기온을 이용한 Hargreaves 방법 (Hargreaves, 1985)과 Priestley-Taylor 방법 (Priestley and Taylor, 1972) 등의 세 가지 방법을 소개하였다. 세 가지 방법으로 산정된 잠재 증발산을 통해 해당 유역의 잠재 증발산의 공간적인 거동을 파악해 볼 수 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.128-128
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• 2019

증발산량은 수표면이나 토양면에서 수증기의 형태로, 대기중으로 방출되는 증발량과 식물의 엽면을 통해 지중의 물이 대기 중으로 방출되는 증산량의 합으로, 기상학과 수문학에 사용되는 중요한 농업기상 매개 변수이다. 증발산량을 관측하는 방법으로는 라이시미터 (Lysimeter)와 같은 관측장비를 통해 실제 증발산량을 측정하는 방법과, FAO-56 Penman-Monteith (PM)과 같은 증발산량 추정 알고리즘을 이용하여 산출하는 방법이 있다. 국내의 경우 기상관측소에서 수집한 데이터를 이용하여 증발산량 추정공식을 통해 증발산량을 산정하는 연구가 이루어졌으며, 위성영상에 기반하여 증발산을 추정하려는 연구가 진행되고 있다. 본 연구에서는 미국 항공우주국 (National Aeronautics and Space Administration, NASA)에서 추진하는 위성을 이용한 지구 전역의 장기관측 계획 EOS (Earth Observing System)에 의해 발사된 지구 관측 위성인 MODIS Terra 위성에서 제공되는 MOD16A2 위성영상을 사용하였다. MOD16A2 위성영상은 2001년부터 현재까지 500m의 픽셀 단위로 제공되는 8일 간격의 전지구 규모의 위성영상으로, 본 연구에서는 우리나라 관측소에서 관측된 기상인자를 PM 공식에 입력하여 산정된 증발산량 값과 MOD16A2 위성영상 데이터를 비교하여 우리나라 MOD16A2 위성영상 적용성 및 밭작물 가뭄분석에 적용하였다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.1
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• pp.15-24
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• 2010

This study was conducted to investigate the effects of swine manure (SM) application with additional nitrogen (N) fertilizer on productivity of corn and environmental pollution in com cultivation soil. The experiment was conformed in lysimeter which was constructed with 30 cm diameter, and 100 cm height. Swine manures used in this study were the compost of swine manure fermented with sawdust (SMFWS) and soft rice hulls treated with high temperature and high pressure (SRH), and swine slurry (SS). The application rates of the additional N, as urea, with swine manure were 50 and 100 kgN/ha on each plot. This study was arranged in completely randomized design with three replication. DM yields in SM treatments with mineral N were increased significantly compared to those in SM treatment without mineral N (zero-mineral N) (P<0.05) and increased as the rate of mineral N application increased (P<0.05). DM yields in SMFWS and SS treatments with mineral 100 kgN/ha showed trends similar to those of chemical fertilizer (control) but higher than those of 50 kg N/ha. DM yields tended to be higher in SMFWS and SS treatments than in SRH treatment. Total N contents in SMFWS, SRH and SS treatments with mineral N were increased, compared with SM treatment without mineral N. N contents in SM treatments with mineral N were lower than those of chemical fertilizer treatment, but N content of chemical fertilizer treatment showed trends similar to that of SS treatments with mineral 100 kgN/ha. $NO_3$-N concentration in SM treatments with mineral N were increased significantly, compared to those in SM treatment without mineral N and in chemical fertilizer (P<0.05). $NH_4$-N concentrations in SMFWS and SS treatments with mineral 100 kgN/ha showed trends similar to those of chemical fertilizer, but higher than those of 50 kg N/ha. $PO_4$-P concentration in SM treatments with mineral N were increased significantly, compared to those in SM treatment without mineral N (P<0.05). $PO_4$-P concentration in chemical fertilizer treatment showed trends similar to that of SS treatments with mineral 100 kgN/ha. The concentrations of $NO_3$-N $NH_4$-N and $PO_4$-P increased as the rate of mineral N application increased (P<0.05). The concentrations of $NO_3$-N $NH_4$-N and $PO_4$-P were highly elevated in the concentrated rainy season in the early stage among experimental period. The maximum $NO_3$-N $NH_4$-N and $PO_4$-P concentrations in the leaching water were 3.46 mg/L, 1.11 mg/L and 0.14 mg/L, respectively.

• Journal of Applied Biological Chemistry
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• v.50 no.1
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• pp.22-28
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• 2007

Most of the uplands in alpine regions during off-season are left as bare soil and thus vulnerable to severe erosion due to the inherent topographical conditions. Appropriate management strategy to cope with this problem is urgently needed, yet few researches have been reported on the effects of winter cover crop and management on soil erosion. We assessed effects of ryegrass (Lolium multiflorum) as cover crop, green manure or mulching residue on soil erosion and quality through field and segment plot lysimeter experiments in alpine uplands. Ryegrass successfully adopted to winter in alpine region based on biomass, nutrient contents, and vigors of top and root systems. Incorporation of ryegrass into soil maintained soil fertility, nutrient uptake, and yield of cabbage exerting potential use as green manure. Cultivation of ryegrass suppressed occurrence of Chinese cabbage pests. Surface coverage by ryegrass as cover crop and mulching residue significantly reduced soil loss up to 96%, when combined with soil conservation management practices. Results revealed maintaining cover crop over winter was beneficial in reducing soil erosion, and sustaining soil quality and Chinese cabbage productivity. This study suggested winter cover crop, followed by green manure and mulching, and conservation tillage system could be one of the best management practices in alpine sloping uplands cultivating Chinese cabbage.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.312-316
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• 2012

Very important factor for crop cultivation are water, nutrient and temperature. However, the essential factor for crop cultivation is water management. Water management is the most important and difficult problems in crop cultivation. The water saving irrigation manual can be used with easy to the farmer and who want automatic irrigation without soil sampling and any kinds of sensors measuring soil water status. The water requirement of red pepper cultivated in plastic film house is different according to soil texture, area as well as climate condition and growth stage. And, the measurement of potential evapo-transpiration (PET) and crop coefficient (Kc) to decide optimum irrigation schedule is very difficult. Results : The average PET during 30 years of northern region of korea for the red pepper cultivation was a $2.31mm\;day^{-1}$. The water saving irrigation manual as water saving is possible, those irrigation interval and amount of irrigation according to growing season and soil texture, are developed using the lysimeter experiments carried out by the RDA for 11 years about potential evapo-transpiration, Kc for the northern region of korea.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.510-518
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• 2013

Corn was mainly cultivated in slope land during summer season when heavy rain falls so that soil loss occurs severely. Especially, soil disturbance and exposure of topsoil by conventional tillage intensifies soil loss by heavy rain. The aim of this study was to develop surface covering and tillage methods for reducing soil loss in corn cultivation. The experiment was conducted in 17% sloped lysimeter with 8 treatments including strip tillage after surface covering with rye residue, strip tillage after residue covering of several crops and sod culture, black polyethylene film covering after conventional tillage and control. Amount of runoff water and eroded soil, and corn growth were investigated. Amounts of runoff water in all plots except black polyethylene plot ranged from 152 to 375 $m^3\;ha^{-1}$, accounting for 13~32% of 1,158 $m^3\;ha^{-1}$ in control. Amount of eroded soil decreased by 94 to 99% (3 to 89 kg $ha^{-1}$) in plots of strip tillage after covering with crop residues compared to control with 1,739 kg $ha^{-1}$. Corn yields in plots of strip tillage after covering with crop residues ranged from 6.0 to 6.9 Mg $ha^{-1}$, while that of control was 6.5 Mg $ha^{-1}$. The results suggest that strip tillage methods after surface covering with crop residues are very effective on soil conservation of slope land in corn cultivation.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.2
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• pp.43-51
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• 2018

The objective of this research was to assess the effect of moisture content and water injection method into the landfill on waste decomposition in an aerobic landfill. Firstly, respirometric experiments were performed in order to assess the effect of initial moisture content (20%, 30%, 40% and 50% respectively) on landfilled waste decomposition. The cumulative oxygen uptake and oxygen uptake rate were highly increased with the increase of initial moisture content. Secondly, lysimeter experiments showed that in comparison with the vertical injection method, dry fog system enhanced decomposition of organic wastes. Also, dry fog system provided uniform moisture distribution more than the vertical injection method within landfill.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.2
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• pp.112-118
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• 1983

Rainfall factor (R-factor), which is an index for the prediction of soil erosion in the Universal Soil Loss Equation (USLE), was computed from 21 years rainfall data at 51 locations in Korea. The values of R-factor are from 200 to 300 in the eastern part, and 300 to 700 in the western and southern part of the peninsula. Curvilinear regressions exist between annual rainfall and annual R-factor or between monthly rainfall and monthly R-factor. The R-factor can be estimated from the regression equation as a function of the amount of rainfall. According to the comparison between the actual soil loss measured by lysimeter and the soil loss predicted by the USLE, EI 30 for R-factor was recognized as a suitable factor for the USLE in korea.