• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.459-465
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• 2012

This study was conducted to obtain investigated characteristic factors which has an influence on nitrous oxide ($N_2O$) emissions related to the environment change of nitrogen application level, rainfall and temperature. It was done by the carrot cultivation at black volcanic ashes soil in the experimental field of Jeju Special Self-governing Province Agricultural Research and Extension Services from 2010 to 2011. During the carrot cultivation period, the more amount of nitrogen fertilizer applied, the more amount of $N_2O$ emissions were released. Generally $N_2O$ emissions were so deeply released to climate as that in the first and middle of cultivation with heavy rainfall released amount is high, otherwise it was released very low at the end of cultivation and drought season. $N_2O$ emissions type was considered to relate with the rainfall pattern and soil water content. We obtained the result correlated with $N_2O$ emissions, in 2010, as the soil water and soil temperature were significant to $0.5718^{**}$ ($r$) and $0.4908^{**}$ ($r$) respectively, but soil EC was not significant to 0.2704 ($r$). In 2011, soil water was significant to $0.3394^*$ ($r$), but soil temperature and soil EC were not significant to 0.2138 ($r$) and 0.2462 ($r$) respectively. Also, $NO_3$-N and soil nitrogen ($NO_3-N+NH_4-N$) were not significant to 0.0575 ($r$) and 0.0787 ($r$) respectively. During the carrot cultivation period, the average emissions factor released by the nitrogen fertilizer application for 2 years was presumed to be 0.0025 $N_2O$-N kg / N kg. This factor was 4 times than the IPCC (0.0100 $N_2O$-N kg / N kg) factor.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.231-235
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• 2009

본 연구에서는 홍수예보를 위한 사상형 모형인 저류함수모형 적용시 문제점을 개선하기 위해 기존의 저류함수 모형에 자유수와 장력수의 2개 영역으로 구성된 토양수분모의 컴포넌트를 결합하여 지표유출, 중간유출, 기저유출의 유출수문성분에 대한 연속적인 모의가 가능하도록 하였으며 실시간 홍수예측을 위해 다수의 유량 관측지점과의 실시간 오차 보정이 가능하도록 앙상블 칼만 필터링 기법을 도입하였다. 개발된 모형의 적용성을 평가하기 위해 낙동강 권역을 대상유역으로 선정하였으며 시단위 강우자료, 기상자료, 유량자료를 비롯하여 GIS를 기반의 지형자료를 구축하였다. 연속형 저류함수형의 매개변수 추정결과 주요지점의 관측유량에 대해 높은 적합도를 보였으며 1시간 선행시간의 홍수량 예측결과에서도 높은 정확도를 보이는 것으로 나타났다.

• 한국방재학회:학술대회논문집
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• 2010.02a
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• pp.115.2-115.2
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• 2010

2008년 늦가을부터 2009년 봄까지 강원도 일부 지방에서 심각한 가뭄이 발생하여 태백지역에서는 87일 동안 제한급수가 실시되는 등 지역 주민들이 겪는 고통은 상당하였다. 2009년 태백시에서 발간한 가뭄백서에 따르면, 이번 가뭄으로 인한 태백지역의 피해 추정액은 980여억 원에 달한다고 한다. 본 연구에서는 가뭄지수들 중 토양수분지수(Soil Moisture Index)와 수자원가용지수(Water Availability Index)를 이용하여 태백지역에서 발생한 가뭄을 농업과 수문학적 관점으로 분류하여 정량화 하였다. 또한 태백지역의 물공급을 맡고 있는 광동댐의 운영을 분석함으로써 이번 가뭄의 발생 원인을 보다 심층적으로 분석하였다. 연구결과, 홍수기 동안 광동댐의 운영을 개선하여 9월초에 저수량을 충분히 확보하는 것이 태백지역 가뭄 해소의 관건임을 확인하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.308-308
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• 2018

전 지구적으로 댐 건설과 가정, 공업 및 농업 용수의 사용 등 인간의 영향으로 유출량, 지하수, 토양수분 등의 다양한 수문요소가 변화를 보이고 있다. 이러한 인간의 영향은 기후변화의 영향과 함께 수문요소에 주요한 동인으로 이의 영향을 이해하고 전망할 필요가 있다. 본 연구는 Inter-Sectoral Impact Model Intercomparison Project를 통해 이용 가능한 여러 글로벌 수자원 모형의 결과를 분석하여 기후변화 및 인간활동의 영향의 상대적 중요성 등을 분석하고자 한다. GFDL, HadGEM, IPSL, MIROC5에서 도출된 기후 시나리오를 기반으로 구동된 글로벌 수자원 모형결과를 살펴보고자 하며, 글로벌 수자원 모형은 CLM, H08, JULES 등을 포함한다. 본 연구에서는 증발산량, 토양수분, 유출 등의 시간 및 공간적 변화, 기후변화 및 인간 활동의 영향이 주요한 역할을 하는 지역 혹은 유역을 확인하는데 초점을 맞추고자 한다.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.3
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• pp.199-206
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• 1982

A field experiment was conducted to compare the effects of compost and rice straw application on the growth of soybean, chemical properties and soil microorganism in newly reclaimed silty clay loamy upland soil. Application rates of the arganic materials were 750 Kg, 1,500 Kg and 3,000 Kg/10a in compost, and 340 Kg, 680 Kg and 1,360 Kg/10a in rice straw. The differences of N.P.K. application rates caused by the two different organic materials were balanced by chemical fertilizers of N.P.K. The results can be summarized as follows; 1. The yield of soybean was increased upon compost application, but no significant difference on yield was observed except luxuriant plant growth upon rice straw application. 2. There was highly possitive correlation between concentration of phosphorous, potassium in soybean plant at 71 days after planting and dry weight of grain vs. stem plus bean chaff of harvest plant in compost applied plots, but no correlation was found in rice straw applied plots. 3. In greneral, the soil water contents in organic material applied plots, expecially in plots of rice straw, were higher than in no organic material plots. However, at wilting point, the soil water content in organic material applied plot was lower compare to no organic material plot. 4. The weight of nodules per soybean plant was heavier notwithstanding the fewer number of soil bacteria and fungi in compost application plots than rice straw application plots.

• Journal of Korean Society of Forest Science
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• v.38 no.1
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• pp.46-54
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• 1978

In afforestation of denuded forest land soil conditions play a very important role in early growth of cover vegetations. This study was designed for understanding the effect of soil moisture regime on growth and nutrient uptake of some seedlings. Cover vegetations such as Pinus rigida Miller, Robinia pseudoacacia L. and Lespedeza bicolor Turcz. were planted in pot with the soil transported from denuded forest land in Musu-ri Sannae-Myeon. Daedeog-Kun, Chungnam Province. There were 3 moisture treatments and 4 fertility levels in $P_2O_5$ with 4 replications. Influence on growth was observed by the variation in dry weight and nutrient uptake was studied in nitrogen, phosphate and kalium. Results are as follows: 1. For Pinus rigida seedlings decrease in soil moisture tension increases growth of dry weight and enhance the uptake of kalium. Increase in $P_2O_5$ fertility level tends to decrease the uptake of kalium rather than increase in $P_2O_5$ uptake. 2. In Robinia pseudoacacia increase in soil moisture content stimulates the uptake of nitrogen and kalium. Increase in $P_2O_5$ level enhances the uptake of $P_2O_5$ and increases growth of dry weight. 3. In Lespedeza bicolor increase in soil moisture content has a tendency of decrease in nitrogen uptake. Increase in $P_2O_5$ level increases the growth of dry weight as well as the uptake of $P_2O_5$.

• Journal of Korean Society of Forest Science
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• v.107 no.1
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• pp.1-15
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• 2018

In order to determine the effects of thinning on mushroom fruiting, microclimate and air temperature in Quercus mongolica forests, this study investigated changes in crown density, soil temperature, air temperature and throughfall in the natural Q. mongolica forest which was thinned by approximately 45% four years ago. The results showed that crown density was smaller than control by 6% from April to October, The soil temperature and air temperature in the thinned stands were significantly higher than those of the control by $1{\sim}2^{\circ}C$ until August and differences in air and soil temperature. The average daily temperature difference was higher than control by $0.2{\sim}0.7^{\circ}C$ until October. Throughfall from July to September in the thinned was approximately 135 mm higher than in the control. The maximum difference in throughfall per unit time was 3.5 mm/h. Soil moisture in the thinned site increased by approximately 5% compared with the control and reduced to the normal moisture after 4 days in both sites. 55 mushroom species were found in the thinned area between July and September. The thinned site contained 10 mycorrhizal mushrooms more than the control and 1 saprophytic mushroom species more than the control. Shannon-Wiener Index was 3.2, approximately 0.5 higher than the control. Tylopilus neofelleus, etc., occurred in the thinned site more quickly, but Aaricus subrutilescens, Clitocybe sp, occurred later. In the thinned site, the dominance of Tylopilus neofellelus and Armillaria sp. increased approximately 6% and 30% and yield about 1.5 times and 20 times, respectively. In conclusion, thinning in the Q. mongolica forest increased the soil and air temperature, soil moisture, throughfall and the diversity of mushroom species, and advanced the period of occurrence, and increased dominance and yield of some mycorrhizal mushrooms and Amillaria sp.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.4
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• pp.336-341
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• 1996

This study was conducted to investigate the effects of compost application on the soil loss and physico-chemical properties at the slope land from 1990 to 1991. Lysimeters with 15% slope. 5m slope length. 2m width and 1.2m depth were constructed in 1984 and filled with sandy loam, loam, clay loam. and clay soils. Treatments were bare soil, compost(1.5ton/10a) and non-compost with soybean-barley cropping system from 1984. Losses of soil were increased with the order of sandy loam, clay, loam and clay loam. Run-off was increased with the order of sandy loam, loam, clay loam and clay, but leachate was decreased with the same order. Compost treatments decreased 33.6-44.6% of soil loss and 17.0-24.0% of run-off but increased 17.1-33.7.% of leachate as compared with the non-compost treatments. The amount of soil loss was positively correlated with the amount of run-off by Y = 12.125+0.063X (r=$0.970^{**}$)and negatively correlated with the leachate by Y=43.425-0.096X(r=$-0.917^{**}$). The application of compost increased soil pH, OM, CEC and extractable cations. Application of compost decreased bulk density but increased porosity, water stable aggregate and available water. These results provide that the compost application plays an important role in conserving soil and water, and improving soil physico-chemical properties.

• Journal of Korea Water Resources Association
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• v.39 no.4 s.165
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• pp.299-311
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• 2006

In this paper it is outlined the methodology of estimating the parameters of water balance analysis method for calculating recharge, using ground water level rises in monitoring well when values of specific yield of aquifer are not available. This methodology is applied for two monitoring wells of the case study area in northern area of the Jeiu Island. A water balance of soil layer of plant rooting zone is computed on a daily basis in the following manner. Diect runoff is estimated by using SCS method. Potential evapotranspiration calculated with Penman-Monteith equation is multiplied by crop coefficients($K_c$) and water stress coefficient to compute actual evapotranspiration(AET). Daily runoff and AET is subtracted from the rainfall plus the soil water storage of the previous day. Soil water remaining above soil water retention capacity(SWRC) is assumed to be recharge. Parameters such as the SCS curve number, SWRC and Kc are estimated from a linear relationship between water level rise and recharge for rainfall events. The upper threshold value of specific yield($n_m$) at the monitoring well location is derived from the relationship between rainfall and the resulting water level rise. The specific yield($n_c$) and the coefficient of determination ($R^2$) are calculated from a linear relationship between observed water level rise and calculated recharge for the different simulations. A set of parameter values with maximum value of $R^2$ is selected among parameter values with calculated specific yield($n_c$) less than the upper threshold value of specific yield($n_m$). Results applied for two monitoring wells show that the 81% of variance of the observed water level rises are explained by calculated recharge with the estimated parameters. It is shown that the data of groundwater level is useful in estimating the parameter of water balance analysis method for calculating recharge.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.2
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• pp.75-80
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• 2002

The severity of drought in (the) irrigation reservoir could be evaluated by the accumulative rainfall method, soil moisture content method, storage ratio method, and water supply restricted intensity method, etc. The storage ratio method would be the most reliable one for irrigation reservoir. The pattern of drought might be forecast with the most similar pattern of accumulative rainfall and/or storage ratio out of the file of past operation history.