• Korean Journal of Soil Science and Fertilizer
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• v.36 no.3
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• pp.119-126
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• 2003

Nitrate-N concentrations and the corresponding ${\delta}^{15}N$ values were determined with water samples collected periodically from artesian wells (3 and 6 m deep), underdrainage and gushout waters in a Welsh onion cultivated area in the Kushibiki Fan, Saitama Prefecture, Japan. Average $NO_3-N$ concentrations in waters from 3 and 6 m wells were 25.7 and $2.8mg\;L^{-1}$, whereas ${\delta}^{15}N$ values were 3.6 and 4.7‰, respectively. The $NO_3-N$ concentration and ${\delta}^{15}N$ value of the underdrainge water were $35.5mg\;L^{-1}$ and 6.6‰, reflecting rapid input of chemical fertilizers and farmyard manure. The mean values of $NO_3-N$ concentration and ${\delta}^{15}N$ in the gushout water flown out of the edge of Kushibiki Fan were $19.4mg\;L^{-1}$ and 7.9‰, respectively. As a results the ${\delta}^{15}N$ values of the gushout water were higher than those of the artesian wells and underdrinage water. The ${\delta}^{15}N$ values of total-N and $NO_3-N$ of the soils were 6.1 and 5.10‰, respectively, while those for nitrification-inhibitor containing fertilizer and slow-release fertilizers were -6.1 and -2.2‰, respectively.

• Journal of Environmental Impact Assessment
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• v.19 no.3
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• pp.281-296
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• 2010

방그라데시 북부에 위치한 풀바리 우파질라 지역의 지하수에서 pH, EC, 주요 양이온 ($Ca^{2+}$, $Mg^{2+}$, $Na^+$, $K^+$, $Zn^{2+}$, $Cu^{2+}$, $Mn^{2+}$, $Fe^{3+}$, and $As^{3+}$), 주요 음이온 (${CO_3}^{2-}$, $HCO_3{^-}$, $NO_3{^-}$, ${SO_4}^{2-}$ and $Cl^-$) 그리고 total dissolved solids (TDS) 등의 용존물질 함량을 측정하였다. 또한 sodium adsorption ratio (SAR), soluble sodium percentage (SSP), residual sodium carbonate (RSC), 경도 등의 지표도 계산하였다. 전체적으로 지하수의 pH는 약알칼리성 (6.24 - 8.10)을 띄었으며, 주요 양이온은 $Ca^{2+}$, $Mg^{2+}$ and $Na^+$ 이었고, 주요 음이온은 $HCO_3{^-}$ and $Cl^-$ 으로서 전형적인 담수의 이온조성을 보였다. $Cu^{2+}$, $Mn^{2+}$ and $Fe^{3+}$ 의 최대 농도는 각각 1.71, 0.606, 0.125 mg/L 이었다. 방글라데시의 여러 지역에서는 비소에 의한 지하수의 오염이 흔히 나 타나고 있으나 이지역에서 비소의 최대농도가 0.41 mg/L로서 기준치인 0.05 mg/L 보다 낮은 오 염도를 보였다. TDS와 SAR, SSP 등으로 볼 때 이 지역의 지하수는 대부분 양호한 수질을 가지는 담수인 것으로 평가된다. $As^{3+}$, $Zn^{2+}$, $Mn^{2+}$, $Fe^{3+}$, ${SO_4}^{2-}$, $NO_3{^-}$ and $Cl^-$ 등의 농도는 음용수로 적합한 수준이었으나 일부 항목은 특정 산업용도로는 부적합한 농도를 보였다. 현재로서는 이지역 의 지하수는 대부분 음용이 가능하고 일부 산업용에 대해서만 부적합성을 보였다. 그러나 앞으로 지 하수의 이용과 산업활동이 증가하면 방글라데시의 많은 다른 지역의 지하수에서 발생한 사례와 같 이 용존물질의 농도가 증가하여 물의 용도에 제한을 받게 될 우려가 있다.

• Korean Journal of Environmental Agriculture
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• v.12 no.1
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• pp.9-17
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• 1993

The leaching behavior of $^{14}C-carbofuran$, $^{14}C-bentazon$, and $^{14}C-3,3,4,4'-tetrachloroazobenzene(TCAB)$ in the forms of freshly treated, 3-month-aged, and 6-month-aged residues, respectively, was investigated in a loamy soil column system. The degradation and mobility of pesticides in soil and the possibility of the contamination of groundwater were followed by this approach: The ambient temperature of $15{\pm}2^{\circ}C$, irrigation by the constant-head method on soil columns, and leaching with 1332 ml of simulated precipitation during 90 days. While the fresh residues of $^{14}C-carbofuran$ and $^{14}C-bentazon$ were very mobile, the aged ones were remarkably reduced in their mobility. Fresh and aged residues of $^{14}C-TCAB$ were very immobile, instead. 3-Keto carbofuran phenol(2,3-dihydro-2,2-dimethyl-3-oxo-7-benzofuranol) was the major degradation product present in the leachate from the soil column containing freshly treated $^{14}C-carbofuran$, while no metabolites could be detected in the leachates from the columns containing $^{14}C-bentazon$ or $^{14}C-TCAB$.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.2
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• pp.31-43
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• 1988

The Purpose of this study is to develop the rainfall-delayed response model (RDR Model) which influences the baseflow proportion of rivers as a result of the antecedent precipitation of the previous several months. The assesment of accurate baseflows in the rivers is one of the most important elements for the planning of seasonal water supply for agriculture, water resources development, hydrological studies for the availability of water and design criteria for various irrigation facilities. The Palukan river gauging site which is located in the Pulukan catchment on Bali Island, Indonesia was selected to develop this model. The basic data which has been used comprises the available historic flow records at 19 hydrologic gauging stations and 77 rainfall stations on Bali Island in the study. The methology adopted for the derivation of the RDR model was the water balance equation which is commonly used for any natural catcbment ie.P=R+(catchment losses) -R+(ET+DP+DSM+DGW). The catchment losses consist of evapotranspiration, deep percolation. change in soil moisture, and change in groundwater storage. The catchment areal rainfall has been generated by applying the combination method of Thiessen polygon and Isohyetal lines in the studies. The results obtained from the studies may be summarized as follows ; 1. The rainfall-runoff relationship derived from the water balance equation is as shown below, assuming a relationship of the form Y=AX+B. Finally these two equations for the annual runoff were derived ; ARO$_1$=0.855 ARF-821, ARF>=l,400mm ARO$_2$=0.290ARF- 33, ARF<1,400mm 2. It was found that the correction of observed precipitation by a combination of Thiessen polygons and Isohyetal lines gave good correlation. 3. Analysis of historic flow data and rainfall, shows that surface runoff and base flow are 52 % and 48% (equivalent to 59.4 mm) of the annual runoff, respectively. 4. Among the eight trial RDR models run, Model C provided the correlation with historic flow data. The number of months over which baseflow is distributed and the relative proportions of rainfall contributing in each month, were estimated by performing several trial runs using data for the Pulukan catchment These resulted in a value for N of 4 months with contributing proportions of 0.45, 0.50, 0.03 and 0.02. Thus the baseflow in any month is given by : P$_1$(n) =0.45 P(n) +0.50 P(n-I ) +0.03 P(n-$_2$) +0.02 P(n-$_3$) 5. The RDR model test gave estimated flows within +3.4 % and -1.0 % of the observed flows. 6. In the case of 3 consecutive no rain months, it was verified that 2.8 % of the dependable annual flow will be carried over the following year and 5.8 % of the potential annual baseflow will be transfered to the next year as a result of the rainfall-delayed response. The results of evaluating the pefformance of the RDR Model was generally satisfactory.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.87-101
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• 1999

This study has been carried out to examine the feasibility of washing technique for reducing the heavy metal contamination level of tailing wastes and agricultural soil surrounding abandoned metal mines. Some organic acids with low molecular weight were used as washing solution. Initial contamination levels of copper and lead for some soil samples were found to exceed the standard levels of countermeasure and concern, and those of cadmium to approach the standard level of countermeasure. Experimental results using sequential extraction method revealed that more than half of copper and lead existing in tailing wastes are adsorbed forms available for plants. There are some proportional relationships between metal concentrations determined by using 0.1N HCI solution and those determined by sequential extractions. Citric acid was turned out to be superior to oxalic acid and acetic acid with low molecular weight in washing above three metals. When citric acid is used for washing heavy metals from soil, it is desirable to operate at pH less than 5.5 for better washing effect. Metal removal effect by citric acid solution has been proved to depend upon solution concentration and the mass ratio of solution to soil. Addition of SDS(Sodium Dodecyl Sulfate) to citric acid improved the washing effect of cadmium among three metal most significantly. while copper removal did not change. Washing technique using citric acid for removal of heavy metals from agricultural soil or tailing wastes is recognized to be an effective remediation method.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.490-495
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• 2005

Organic compost has been widely applied to the cropland because it has been thought as Environmentally Sound Agriculture (ESA) in Korea. However, many field researches have been done to investigate water quality impacts of organic compost uses, compared to those from chemical fertilizer applications. It was found that pollutant loads from organic compost applied croplands were higher than those from chemical fertilizer applied areas. However, there might be other unknown factors affecting the results since the experiments were performed at the outside fields. In this study, indoor rainfall experiments using the Norton rainfall simulator systems were done to minimize and exclude errors from unknown sources by controlling soil characteristics, rainfall amount, rainfall intensity, and fertilizer treatments. The amounts of surface runoff and groundwater percolated from 10% and 20% slope plots were measured and water quality samples were collected and analyzed for BOD, COD, and T-P. Flow weighted mean concentration (FWMC) values were computed to assess effects of different fertilizer treatments. It was found that average concentration values of BOD were 5.57 mg/L from chemical fertilizer treated plot and 8.08 mg/L from organic compost treated plots. For 10% slope, FWMC BOD values from organic compost treated plots were higher by 29.9% than those from chemical fertilizer treated plots. For 20% slope, FWMC BOD values from organic plots were higher by 38.8% than those from chemical fertilizer plots. FWMC BOD values for 20% slope plots were higher than those from those for 10% slope plots. The similar trends were found for COD and T-P. In Korea, excessive use of organic compost has caused extremely high levels of organic matter contents at the cropland. Organic compost are usually applied to the cropland to improve soil quality, while chemical fertilizer is applied to help crop growth. Since organic compost is very slow in releasing its nutrients to the soil, farmers usually apply excessive organic compost for immediate effects and maximum crop yields, which has been causing soil and water quality degradations. Therefore, thorough investigations for better nutrient management plans are needed to develop the ESA strategy in Korea.

• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.215-220
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• 1999

Behaviour of a fungicide $^{14}C-propiconazole$ was investigated in a rice plant grown-lysimeter soil. The lysimeter was composed of soil cores of silty clay. $Propiconazole(Tilt\;250^R\;EC)$ plus $^{14}C-labeled$ propiconazole was applied on the surface of lysimeter soil at a rate of 0.12kg/10a after rice transplanting. The application was done consecutively for two years. The behaviours of propiconazole in the lysimeter soil were investigated by measuring the amounts of $^{14}C-leachate$, $^{14}CO_2$, the residues distributed in each soil segment and taken up by rice plants. The relative amounts of $^{14}C$ leached from the lysimeter were the background level of the applied $^{14}C$ throughout expeiment. The amounts of $^{14}CO_2$ evolved from the lysimeter were 5.7 and 7.8% of the original $^{14}C$ in the 1st and 2nd treatment, respectively. The amounts of volatile substances soil were the background level throughout experiment, which indicated that propiconazole was stable chemically in the experimental condition. The $^{14}C-activities$ absorbed and translocated into rice plants were 3.7 and 7.6% in 1st and 2nd treatment, respectively. The $^{14}C-activities$ in the soil layer of the lysimeter was distributed mainly in the depth of 0 to 20cm, which suggested propiconazole did not have the risk of groundwater contamination.

• The Journal of Engineering Geology
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• v.12 no.4
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• pp.471-484
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• 2002

Alluviums in the Keum River watershed cover an areal extent of $3,029{\;}\textrm{km}^2$ and contain about 8.1 billion tons of groundwater. However, the waters are severely polluted by nitrate, possibly due to the application of nitrogen fertilizer (>250 N kg/ha) on agricultural land. This paper aims to elucidate the pollution status and behaviors of nitrate in alluvial groundwaters in the Keum River watershed area, based on regional hydrogeochemical study. Most of the collected samples (n = 186) are polluted by nitrate (average = 42.2 mg/L, maximum = 295 mg/L). About 29% of the samples have the nitrate concentrations exceeding Korean Drinking Water Standard (44 mg/L $NO_3$). The distribution of nitrate concentrations in the study area is largely dependant on geochemical environments of alluvial aquifers. In particular, the decrease of redox potential of alluvial groundwaters showed a good correlation with the decreases of nitrate, iron, and manganese concentrations. Thus, the change of redox state in alluvial aquifers, likely reflecting their sedimentary environments, controls both the behavior and fate of nitrogen compounds and their natural attenuation (denitrification) in aquifers. A carbon-rich, silty layer within alluvium strata forms a reducing condition and possesses a buffering capacity on nitrate pollution.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.4
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• pp.3160-3169
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• 1973

Rainfall, evaporation, and permeability of water are the most important factors in determining the demand of water. The Daegu area has only a meteorologi observatory and there is not sufficient data for adapting the advanced method for derivation of the estimated of evaporation in the Daegu area. However, by using available data, the writer devoted his great effort in deriving the most reasonable formula applicable to the Daegu area and it is adaptable for various purposes such as industry and estimation of groundwater etc. The data used in this study was the monthly amount of evaporation of the Daegu area for the past 13 years(1960 to 1970). A year can be divided into two groups by relative degrees of evaporation in this area: the first group (less evaporation) is January, February, March, October, November, and December, and the second (more evaporation) is April, May, June, July, August, and September. The amount of evaporation of the two groups were statistically treated by the theory of probability for derivation of estimated formula of evaporation. The formula derved is believed to fully consider. The characteristic hydrological environment of this area as the following shows: log(x＋3)=0.8963＋0.1125$\xi$..........(4, 5, 6, 7, 8, 9 month) log(x-0.7)=0.2051＋0.3023$\xi$..........(1, 2, 3, 10, 11, 12 month) This study obtained the above formula of probability of the monthly evaporation of this area by using the relation: $F_(x)=\frac{1}{{\surd}{\pi}}\int\limits_{-\infty}^{\xi}e^{-\xi2}d{\xi}\;{\xi}=alog_{\alpha}({\frac{x_0+b'}{x_0+b})\;(-b<x<{\infty})$ $$log(x_0＋b)=0.80961$ $$\frac{1}{a}=\sqrt{\frac{2N}{N-1}}\;Sx=0.1125$$ $$b=\frac{1}{m}\sum\limits_{i-I}^{m}b_s=3.14$$ $$S_x=\sqrt{\frac{1}{N}\sum\limits_{i-I}^{N}\{log(x_i+b)\}^2-\{log(x_i+b)\}^2}=0.0791$$ (4, 5, 6, 7, 8, 9 month) This formula may be advantageously applied to estimation of evaporation in the Daegu area. Notation for general terms has been denoted by following: $W_(x)$: probability of occurance. $$W_(x)=\int_x^{\infty}f(x)dx$$ P : probability $$P=\frac{N!}{t!(N-t)}{F_i^{N-{\pi}}(1-F_i)^l$$ $$F_{\eta}:\; Thomas\;plot\;F_{\eta}=(1-\frac{n}{N+1})$$ $X_l\;X_i$: maximun, minimum value of total number of sample size(other notation for general terms was used as needed)

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.6
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• pp.127-135
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• 2017

In this study, a cold well and a warm one with the distance of 100 m were installed in the alluvial aquifer. Groundwater used as the heat and the cold source of heat pump was designed to flow into the warm and the cold well with a diameter of 200 mm. In order to increase the heat and cold storage in aquifer, six auxiliary wells with the diameter of 50 mm and the depth of 30 m were installed at an interval of 5 m from the main well. Also, heat pump 50 RT, the thermal tank $40m^3$, and a remote control and monitoring system were installed in three single-span greenhouses ($2,100m^2$) for growing tomato in Buyeo, Chungcheongnam-do. According to the aquifer heat storage test which had been conducted from Aug. 31 to Sep. 22, 2016, warm water of $850m^3$ was found to flow into warm well. The temperature of the injected water was $30^{\circ}C$ (intake temperature : $15^{\circ}C$), and the heat of 12.8 Gcal was stored. The greenhouse heating test in winter had been conducted from Nov. 21, 2016 to Apr. 30, 2017. On Nov. 21, 2016 when heating greenhouse started, the aquifer temperature of the warm well was $18.5^{\circ}C$. The COP for heating with water source at $18.5^{\circ}C$ was 3.8. The intake water temperature of warm well was gradually lowered to the temperature of $15^{\circ}C$ on Jan. 2, 2017 and the heat pump COP was measured to be 3.2 at that time. As a result, the heat pump COP was improved by 18 %. and retrieval heat was 8 Gcal, the retrieval rate of heat stored in aquifer was estimated at 63 %.