• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.516-516
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• 2015

본 연구는 한강유역($2,6018km^2$)을 대상으로 SWAT(Soil and Water Assessment Tool)을 이용하여 지표수와 지하수의 상호작용에 의한 물수지 분석을 수행하고, 수량측면의 유역 건전성을 평가하였다. 유역의 물수지 분석을 위해 한강유역을 표준유역 단위로 구분하고, 기상자료, 하천유량, 다목적댐(소양강댐, 충주댐, 횡성댐) 운영자료, 다기능보(강천보, 여주보, 이포보) 운영자료, 증발산량, 토양수분 자료를 수집하였다. SWAT 모형의 신뢰성 있는 유출량 보정을 위해 한강유역 내 위치하는 다목적댐 및 다기능보의 실측 방류량을 이용하여 댐 운영모의를 고려하였고, 실측 지하수위, 증발산, 토양수분 자료를 이용하여 모형의 보정(2005~2009)과 검증(2010~2014)을 실시하였다. 그 결과 토양수분으로부터 증발산이 발생하고 유출 및 지하수까지 영향을 미치는 물수지 현상을 잘 재현하고 있음을 알 수 있었다. 이후 유역의 수량측면의 건전성 평가를 위한 수문요소로 하천 유출량, 증발산량, 침투, 침루, 기저유출, 토양수분, 지하수 함양량 등을 도출하고 유역의 물순환을 해석하여 유역의 건전성을 평가하였다.

• Horticultural Science & Technology
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• v.18 no.6
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• pp.839-844
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• 2000

In developing of soil wetting agents using the mixture of polyoxyethylene octylphenyl ether [$C_8H_{17}O$ $(C_2H_4O)_{10}H$, POE] and polyoxyethylene+polypropyleneoxide tridecylether (1:1, w/w, CM-1), the effect of base carriers such as zeolite and vermiculite on changes of concentration of POE and on initial wetting of peat-vermiculite media were determined. The concentration of POE in the treatment of zeolite was higher than that of vermiculite. The treatments of POE+CM-1 with zeolite or vermiculite as carrier were effective in initial water retention of root media having about 510 mL of water per pot, where those of AquaGro and control had 490 mL and 400 mL of water per pot, respectively. In the evaporative water loss, the treatment of zeolite and AquaGro were faster than those of control and vermiculite. The treatment of AquaGro had faster water movement in root media than those of POE+CM-1 regardless of carriers and same trends were observed in the volume of water infiltrating into root media. Also, increasing the amount of POE+CM-1 resulted in increased water retention capacity, evaporative water loss, water movement in root media and amount of water infiltrating into root media.

• Korean Journal of Medicinal Crop Science
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• v.16 no.4
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• pp.207-210
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• 2008

It is very important factors to control optimal light transmission ratio and soil moisture content in order to produce good quality of ginseng seedling. To study the effect of light transmission ratio (LTR) and soil moisture content(SMC) on growth characteristics and yield of ginseng seedling, LTR was controlled by three level such as 21.2, 24.8% and 30.3%, and SMC was plotted by four level of 11.0%, 12.5%, 15.3% and 18.9% at the greenhouse. Chlorophyll content was gradually decreased in the low LTR (21.2%), while it was distinctly decreased by the decrease of SMC in excessively high LTR (30.3%). The decrease of SMC in the high LTR increased heat injury ratio distinctly, while heat injury ratio in the low LTR was only increased when SMC was very low such as 11.0%. All of fresh root weight per Kan (3.3$m^2$), root weight per plant, and the number of usable seedling were distinctly decreased by the increase of LTR and the decrease of SMC. Excessive increase of LTR in optimal SMC (18.9%) hadn't a great effect on the decrease of root weight, while root weight in low SMC was distinctly decreased by the increase of LTR. Ratio of rusty root was distinctly increased in the condition that both of LTR and SMC were high. Ratio of rusty root in the excessively high LTR was gradually fallen off by decrease of SMC, but its ratio in low SMC didn't changed distinctly by the decrease of SMC.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.3
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• pp.156-161
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• 1982

In ginseng fields, soil organic matter content showed significant positive correlation with soil moisture content and root yield. Soil moisture content showed significant positive correlation with root yield, stem diameter and stem length but significant negative correlation with relative missing plant rate, defoliation and alternalia bright infection. For more than 2 Kg yield per Kan under present cultivation technique, soil moisture appeared to be greater than 17% and organic matter 2%. Many fields (58%) were below this requirement and belong to sand loam and loam soils.

• Journal of Korea Water Resources Association
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• v.33 no.1
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• pp.61-72
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• 2000

The purpose of this study is to improve the method of evaluating groundwater recharge by using grid-based soil moisture routing technique. A model which predicts temporal variation and spatial distribution of soil moisture on a daily time step was developed. The model uses ASCII-formatted map data supported by the irregular gridded map of the GRASS(Geographic Resources Analysis Support System)-GIS and can generate daily and monthly spatial distribution map of surface runoff, soil moisture content, evapotranspiration within the watershed. The model was applied to Ipyunggyo watershed($75.6\;\textrm{km}^2$) located in the upstream of Bocheongchun watershed. Seven maps; DEM(Digital Elevation Mode]), stream, flow path, soil, land use, Thiessen network and free groundwater level, were used for input data. Predicted streamflows resulting from two years (l995, 1996) daily data were compared with the observed values at the watershed outlet. The results of temporal variations and spatial distributions of soil moisture are presented by using GRASS GIS. As a final result, the monthly predicted groundwater recharge was presented.sented.

• Korean Journal of Remote Sensing
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• v.40 no.2
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• pp.229-241
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• 2024

With the advancement of big data processing technology using cloud platforms, access, processing, and analysis of large-volume data such as satellite imagery have recently been significantly improved. In this study, the Change Detection Method, a relatively simple technique for retrieving soil moisture, was applied to the backscattering coefficient values of pre-processed Sentinel-1 synthetic aperture radar (SAR) satellite imagery product based on Google Earth Engine (GEE), one of those platforms, to estimate the surface soil moisture for six observatories within the Yongdam Dam watershed in South Korea for the period of 2015 to 2023, as well as the watershed average. Subsequently, a correlation analysis was conducted between the estimated values and actual measurements, along with an examination of the applicability of GEE. The results revealed that the surface soil moisture estimated for small areas within the soil moisture observatories of the watershed exhibited low correlations ranging from 0.1 to 0.3 for both VH and VV polarizations, likely due to the inherent measurement accuracy of the SAR satellite imagery and variations in data characteristics. However, the surface soil moisture average, which was derived by extracting the average SAR backscattering coefficient values for the entire watershed area and applying moving averages to mitigate data uncertainties and variability, exhibited significantly improved results at the level of 0.5. The results obtained from estimating soil moisture using GEE demonstrate its utility despite limitations in directly conducting desired analyses due to preprocessed SAR data. However, the efficient processing of extensive satellite imagery data allows for the estimation and evaluation of soil moisture over broad ranges, such as long-term watershed averages. This highlights the effectiveness of GEE in handling vast satellite imagery datasets to assess soil moisture. Based on this, it is anticipated that GEE can be effectively utilized to assess long-term variations of soil moisture average in major dam watersheds, in conjunction with soil moisture observation data from various locations across the country in the future.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.313-313
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• 2022

일반적으로 가뭄은 특정지역에서 평균 이하의 강수량이 발생되는 현상으로, 강수량이 감소되면 토양수분, 하천수 수위, 저수지 수위, 지하수위 등이 순차적으로 감소한다. 수문학적 가뭄은 기상학적 가뭄 및 농업 가뭄에 비해 늦게 발현되는데, 이는 강수량의 부족이 토양수분, 하천수량, 지하수 및 저수지 수위 등과 같은 수문학적 시스템에 전이되는 시간이 소요되기 때문이다. 따라서, 가뭄 피해를 경감하기 위해 지하수위 변동성을 이용하여 지하수 함양량을 추정함으로써 효율적인 수자원 관리의 필요성이 증대되고 있다. 지하수위는 농촌 지하수 개발, 가뭄 및 홍수 예측 등 다양한 분야에 활용되며, 강수량에 의한 변화가 지표수에 비해 느리게 나타나고 토양을 통과하는 특성으로 인해 단기 및 장기간의 변화 경향이 나타난다. 미국 지질조사국 (United States Geological Survey)에서는 지하수위를 월 단위로 보통 이하 (Below-normal), 보통 (Normal), 보통 이상 (Above-normal) 3단계로 구분하여 분포도를 작성하고 전체 관측기간 중 25% 이상에서 보통 이하 (Below-normal)로 나타나면 가뭄으로 판단한다. 우리나라의 경우 지형, 유역을 고려한 지하수 수위 및 수질 현황과 변동성을 파악하기 위하여 전국 지하수위 관측망 688개소를 설치하고 운영 중에 있다. 또한, 농촌진흥청에서는 전국 농업기상대와 연계하여 토양수분관측망 (soil moisture monitoring network)을 구축하였으며, 표토 10 cm에 토양수분센서를 전국 168 지점에 설치하여 운영하고 있다. 본 연구에서는 강수량을 기반으로 산정한 표준강수지수 (Standardized Precipitation Index, SPI)와 지하수위를 기반으로 산정한 표준지하수위지수 (Standardized Groundwater Level Index, SGI), 토양수분관측망의 토양수분의 상관 분석을 수행하고자 한다. 밭작물 가뭄의 중요 요소인 토양수분 함량은 강수에 즉각적으로 반응하는 반면 지표수 및 지하수는 상대적으로 장기간의 강수에 영향을 받기 때문에, 본 연구의 결과는 향후 밭작물 지역의 가뭄 취약성을 관리하는 지표로 활용이 가능할 것으로 사료된다.

• Korean Journal of Medicinal Crop Science
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• v.15 no.6
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• pp.367-370
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• 2007

To make the soil moisture proper is the important factor in the seedbed cultivation of Yangjik for producing a good quality of ginseng seedling. This study was carries out to investigate the effect of soil moisture on photosynthesis and yield of ginseng seedling under the different condition of the soil moisture, such as $100{\sim}400$ mbar. Photosynthesis rate was decreased gradually by the reduction of soil moisture, and in particular it was decreased distinctly under the lower condition of soil moisture, such as $300{\sim}400$ mbar. Photosynthesis rate in air temperature of $30^{\circ}C$ was decreased more distinct than that of $25^{\circ}C$, Light saturation point of leaves was at the quantum of $600{\mu}mol/m^3/s$ at $25^{\circ}C$ while it was decreased by $300{\mu}mol/m^3/s$ at $30^{\circ}C$ according to the increase of air temperature. Respiration rate was increased by the increase of quantum, and decreased by the reduction of soil moisture. Respiration rate under the condition of high quantum was increased regardless of air temperature, but it was decreased distinctly under the condition of low soil moisture and high air temperature, such as 400 mbar at $30^{\circ}C$. There were a gradual decrease by the reduction of soil moisture in leaf length, leaf width, chlorophyll content, and water content of leaves, but heat injury ratio was increased distinctly by the reduction of it. Total root weight, root weight per plant, the yield of usable seedling were decreased by the reduction of soil moisture, and optimal content of soil moisture to produce a good quality of seedling was 63% of field capacity or 18.9% in absolute soil moisture content.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.06a
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• pp.69-73
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• 1998

경기도 퇴촌에 위치한 경희대학교 연습림내의 경사도와 수종을 달리하는 3개의 서로 다른 임반에서 등고선을 따라 지표면의 토층분화를 조사하였고 이에 따른 수분침투특성을 조사하였다. 3개의 임반은 낙엽송, 잣나무 및 굴참나무의 천연활엽수로 구성되었고 이에 구성 수종에 따라 지표면에 퇴적되는 O, A, B층의 깊이를 달리한다. 토층분화 길이는 3개 임반 모두 경사도가 낮은 하부사면에서 양호하게 발달하였으며 경사도가 높은 산사면이나 수간우가 많은 일부 지역에서는 유거수에 의해 유기물이나 표층토가 유실되어 바로 암반층 또는 풍화층이 나타나는 경향을 보이고 있다. 그러나 잣나무 임반의 경우 밀식 수간에 의해 유기물퇴적층과 A층의 발달이 다른 낙엽송이나 굴참나무 임반보다 토층 발달 깊이가 약 2배 이상으로 깊게 발달되었다. 그리고 조사된 임반의 하부사면의 경우 A층의 발달이 약 35cm부터 약 60cm에 이르고 있으나 토성을 구성하는 요소 중 직경 2mm 이상의 자갈에 토양입자들이 전체 토양의 40%정도를 차지하고 있다. 이러한 토층분화 특성을 달리하는 임반에서의 수분 이동특성은 퇴적된 유기물의 두께가 깊으면 깊을수록 수분침투율은 낮아지는 반면 포면 유거수량은 증가하는 경향을 보여주고 있다. 그리고 지표면, 유기물 퇴적층 아래, 지표면으로부터 30cm 아래에 설치된 Lysimeter를 이용하여 조사된 침출수의 분포는 전체를 100으로 환산시 지표면은 약 55%, 유기물퇴적층 아래는 30%, 그라고 30cm의 위치에서는 나머지 15%정도의 침출수가 포집되었다. 따라서 본 실험의 결과를 살펴보았을 때 지표 층에 존재하는 유기물이 전체 수분이동에 영향을 미치는 것으로 조사되었다.양 실험 결과, 서식지에서 조사된 결과인 잎과 줄기에서 Pb$\alpha$ 추정시에는 SeaWiFS 위성과 관련된 global algorithms 중에서 490nm와 555nm의 복합밴드를 포함하는 OC2 알고리즘(ocean color chlorophyll 2 algorithm)을 사용하는 것이 OC2 series 및 OC4 알고리즘보다 좋은 추정 값을 도출할 수 있을 것으로 기대된다.환경에서는 5일에서 7월에 주로 이 충체의 유충이 발육되고 전파되는 것으로 추측되었다.러 가지 방법들을 적극 적용하여 금후 검토해볼 필요가 있을 것이다.잡은 전혀 삭과가 형성되지 않았다. 이 결과는 종간 교잡종을 자방친으로 하고 그 자방친의 화분친을 사용할 때만 교잡이 이루어지고 있음을 나타내고 있다. 따라서 여교잡을 통한 종간잡종 품종육성 활용방안을 금후 적극 확대 검토해야 할 것이다하였다.함을 보이고 있다.X> , ZnCl$_{3}$$^{-}$같은

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.1
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• pp.149-158
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• 2007

To investigate the characteristics of the nitrogen mineralization of oil cakes according to changes in temperature(10, 20, $30^{\circ}C$) moisture(40, 50, 60, 70% of field capacity in loam and 50, 60, 70, 80% of field capacity in sandy loam), mineral nitrogen was measured in soil after incubation for 30 days. In addition, the mineralization in sandy loam and loam which had different soil texture were compared. According to incubating the castor seed, soybean, and rice bran cakes with soil, the higher the temperature and moisture content were, the higher the content of mineral nitrogen was observed. The content of mineral nitrogen was higher in sandy loam than loam. The content of mineral nitrogen was decreased with soil depth increasing and was also higher in sandy loam than loam.