• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.507-507
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• 2022

작물 재배에서 정밀 관개 및 물관리를 위해 토양수분 모니터링이 필수적이며, 최근 이상기후에 따른 가뭄 빈도가 증가함에 따라 토양수분 변동에 따른 적절한 대응이 필요한 실정이다. 특히, 국산밀 생장기의 토양수분 및 관개는 생산성에 중요한 영향을 미치고 있으나, 빈번한 봄가뭄의 영향으로 작물 생산 및 품질 관리의 어려움을 겪고 있다. 따라서 국산밀의 안정적 생산을 위한 토양수분 및 양분 관리에 대한 연구가 필요하다. 본 연구에서는 ICT 기반의 토양 층위별 모니터링 시스템을 구축하여 물관리에 따른 국산밀의 안정적 생산성을 분석하고자 한다. 대상지역은 전라북도 남원시 운봉읍에 위치한 국립식량과학원 운봉시험지이며, 시험포장은 수분처리 조건에 따라 총 4개(A: 한발조건, B: 적정수분, C: 무처리) 처리구로 3개 블록을 구분하여 4반복으로 구성하였다. ICT 기반 10개 토양수분 및 EC (Electrical conductivity) 관측 장비를 통해 실시간으로 자료 수집하였으며, 밀 생육조사는 생육단계별 초장, LAI, 지상부 및 지중 생체중 등 자료를 수집하였다. 수집된 자료는 처리구별 물관리에 따른 토양수분과 생육지표의 상관관계 분석을 통해 가뭄에 따른 생육 영향과 적정 관개용수의 공급시기 및 공급량을 분석하였다. 본 연구는 밀 생장기의 봄가뭄에 대응하기 위한 물관리 기초자료로 활용하고자 하며, ICT 기반의 스마트관리 플랫폼을 개발하여 밀 작황 진단 및 예측을 통해 국산밀의 안정적 생산성에 기여하고자 한다.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.1
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• pp.1-17
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• 1975

Laboratory experiments on the phosphorus adsorption by soil were conducted to evaluate the parameters for determination of phosphorus adsorption capacity of soil, which serve as a basis for establishing the amount of phosphorus required to improve newly reclaimed soil and volcanic ash soil. The calculated Langmuir adsorption maxima varied from 6.2-32.9, 74.7-90.4 and 720-915mg p/100g soil for cultivated soils, non-cultivated soils, and volcanic ash soils respectively. The phosphorus absorption coefficient ranged from 116-179, 161-259 and 1,098-1,205mg p/100g soil for cultivated soils, non-cultivated soils, and volcanic ash soils respectively. The ratio of the phosphorus absorption coefficient to Langmuir adsorption maximum was low in soils of high phosphorus adsorption capacity (1.3-1.5) and high in soils of low phosphorus adsorption capacity (2.2-18.7). Changes in the amount of phosphurus adsorption induced by liming and preaddition of phosphorus were hadly detected by the phosphorus absorption coefficient, which is measured using a test solution with a relatively high phosphorus concentration. The Langmuir adsorption maximum was a more sensitive index of the phosphorus adsorption capacity. The Langmuir adsorption maxima of the non-cultivated soils, which were treated with an amount of calcium hydroxide equivalent to the exchangeable Al and incubated ($25-30^{\circ}C$) for 40 days at field capacity, were lower than the original soils. The change in the adorption maximum on incubation following the liming of soils was insignificant for other soils. The secondary adsorption maximum of soils, which received phosphorus equivalent to the Langmuir adsorption maximum of the limed soils incubated ($25-30^{\circ}C$) for 50 days at held capacity, was 74.5, 5.6 and 23.8% of the primary adsorption maximum for volcanic ash soils, non-cultivated soils, and cultivated soils respectively. The amount of phosphorus adsorbed by soils increased quadratically with the concentration of phosphorus solution added to the soils. The amount of phosphorus adsorbed by 5-g soil samples from 100ml of 100- and 1,000mg p/l solution for the mineral soils and volcanic ash soils respectively was found to be close to the Langmuir adsorption maximum. The amount of the phosphorus adsorbed at these concentrations is defined as a saturation adsorption maximum and proposed as a new parameter for the phosphorus adsorption capacity of the soil. The evaluation of the phosphorus adsorption capacity by the saturation adsorption maximum is regarded as a more practical method in that it obviates the need for the various concentrations used for the determination of the Langmuir adsorption maximum.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.1
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• pp.2913-2924
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• 1973

This study was to investigate the drying mechanism of stratified soil by investigating 'effects of the upper soil on moisture loss of the lower soil and vice versa' and at the same time by examining how the drying progressed in the stratified soils with bare surface and with vegetated surface respectively. There were six plots of the stratified soils with bare surface($A_1- A_6$ plot) and the same other six plots($B_1- B_5$ plot), with vegetated surface(white clover). These six plots were made by permutating two kinds of soils from three kinds of soils; clay loam(CL). Sandy loam(SL). Sand(s). Each layer was leveled by saturating sufficient water. Depth of each plot was 40cm by making each layer 20cm deep and its area. $90{\times}90(cm^2)$. The cell was put at the point of the central and mid-depth of the each layer in the each plot in order to measure the soil moisture by using OHMMETER. soil moisture tester, and movement of soil water from out sides was cut off by putting the vinyl on the four sides. The results obtained were as follow; 1. Drying progressed from the surface layer to the lower layer regardless of plots. There was a tendency thet drying of the upper soil was faster than that of the lower soil and drying of the plot with vegetated surface was also faster than that of the plot with bare surface. 2. Soil moisture was recovered at approximately the field capacity or moisture equivalent by infiltration in the course of drying, when there was a rainfall. 3. Effects of soil texture of the lower soil on dryness of the upper soil in the stratified soil were explained as follows; a) When the lower soil was S and the upper, CL or SL, dryness of the upper soils overlying the lower soil of S was much faster than that overlying the lower soil of SL or CL, because sandy soil, having the small field capacity value and playing a part of the layer cutting off to some extent capillary water supply. Drying of SL was remarkably faster than that of CL in the upper soil. b) When the lower soil was SL and the upper S or CL, drying of the upper soil was the slowest because of the lower SL, having a comparatively large field capacity value. Drying of CL tended to be faster than that of S in the upper soil. c) When the lower soil was CL and the upper S or SL, drying of the upper soil was relatively fast because of the lower CL, having the largest field capacity value but the slowest capillary conductivity. Drying of SL tended to be faster than that of S in the upper soil. 4. According to a change in soil moisture content of the upper soil and the lower soil during a day there was a tendency that soil moisture contents of CL and SL in the upper soil were decreased to its minimum value but that of S increased to its maximum value, during 3 hours between 12.00 and 15.00. There was another tendency that soil moisture contents of CL, SL and S in the lower soil were all slightly decreased by temperature rising and those in a cloudy day were smaller than those in a clear day. 5. The ratio of the accumulated soil moisture consumption to the accumulated guage evaporation in the plot with vegetated surface was generally larger than that in the plot with bare surface. The ratio tended to decrease in the course of time, and also there was a tendency that it mainly depended on the texture of the upper soil at the first period and the texture of the lower soil at the last period. 6. A change in the ratio of the accumulated soil moisture consumption was larger in the lower soil of SL than in the lower soil of S. when the upper soil was CL and the lower, SL and S. The ratio showed the biggest figure among any other plots, and the ratio in the lower soil plot of CL indicated sligtly bigger than that in the lower soil plot of S, when the upper soil was SL and the lower, CL and S. The ratio showed less figure than that of two cases above mentioned, when the upper soil was S and the lower CL and SL and that in the lower soil plot of CL indicated a less ratio than that in the lower soil plot of SL. As a result of this experiments, the various soil layers wero arranged in the following order with regard to the ratio of the accumulated soil moisture consumption: SL/CL>SL/S>CL/SL>CL/S$\fallingdotseq$S/SL>S/CL.

• Korean Journal of Environmental Agriculture
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• v.10 no.2
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• pp.133-137
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• 1991

The inorganic constituents in flay ash such as Ca, Mg, Al and Si were extracted by water and 0.5N-Acetic acid, and changes of the physical properties of the fly ash-treated soils were examined to find out the effect of fly ash on the chemical and physical properties of the soils. The dominant day minerals of fly ash were quartz and mullite. More inorganic constituents were extracted from the fly ash by acetic acid than by water. Si and A1 in fly ash were hardly extracted by water. Addition of fly ash to soil below 10%(W/W) caused improvement in the water permeability and the field moisture capacity of the soil, but did not influence the shrinkage and hardness of the soil. Therefore, it was apparent that the effect of the fly ash on the chemical and physical properties of the soils greatly dependedon soil reaction, the organic acid contents, and the amount of fly ash used in treatment.

• Korean Journal of Weed Science
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• v.4 no.2
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• pp.154-162
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• 1984

The persistence of butachlor and nitrofen in different soil conditions applied organic matter, lime, and other pesticides was studied under submerged and field moisture capacity. Degradation of the herbicides in soil was significantly retarded by autoclaving the soil and half-life of nitrofen was much longer than that of butachlor under this condition. Submerging the soil enhanced degradation of the herbicides, in particular that of nitrofen. On the other hand, half-life of nitrofen under field moisture capacity was twice longer than that of butachlor. Increased amendment of rice straw to the soil shortened the half-life of nitrofen under submerged soil, however it prolonged that of butachlor when the amendment was exceeded 1000kg/10a level. Liming the soil stimulated herbicide decomposition in the soil, which appears to be pH independent. Butachlor degradation in submerged soil was slightly stimulated by simultaneous application of fungicides and insecticides, but nitrofen persistence was not influenced.

• The Korean Journal of Ecology
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• v.26 no.3
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• pp.143-150
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• 2003

Korea has plentiful precipitation but rainfall events concentrate on several months of rainy season in her weather condition. Korea, therefore, experiences drought for a given period every year. Moreover the soil has usually low water holding capacity, as it is composed coarse particles originated from the granite. Response of several oaks and the Korean red pine (Pinus densiflora) on water stress showed that water budget was significant factor determining vegetation distribution. In addition, dehydration level due to cold resistance mechanism of several evergreen plants during the winter season was closely related to their distribution in natural condition. Experimental result under water stress showed that the Korean red pine was very tolerant to desiccation but the seedlings showed high mortality during the dry season. The mortality tended to proportionate to soil moisture content of each site. A comparison between soil moisture content during June when it is severe dry season and moisture content of the culture soil when the pine seedlings reached the permanent wilting point due to water withheld proved that high mortality during the dry season was due to water deficit. Water potential of sample plants measured during the exposure experiment to the air pollutant showed a probability that water related factors would dominate the occurrence of visible damage and the tolerance level of sample plants. In both field survey and laboratory experiment, plants exposed to air pollution showed more rapid transpiration than those grown in the unpolluted condition. The result would due to injury of leaf surface by air pollutants. Aluminum (Al/sup 3+/) increased in the acid soil not only inhibits root growth but also leads to abnormal distribution of root system and thereby caused water stress. The water stresses due to air pollution and soil acidification showed a possibility that they play dominating roles in inducing forest decline additionally to the existing water deficit due to weather and soil conditions in Korea. Sludge, which can contribute to improve field capacity, as it is almost composed of organic matter, showed an effect ameliorating the retarded growth of plant in the acidified soil. The effect was not less than that of dolomite known in widely as such a soil ameliorator. Litter extract contributed also to mitigate the water stress due to toxic Al/sup 3+/. We prepared a model showing the potential interaction of multiple stresses, which can cause forest decline in Korea by synthesizing those results. Furthermore, we suggested restoration plans, which can mitigate such forest decline in terms of soil amelioration and vegetation restoration.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.163-172
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• 1989

In order to study spatial variability of soil physical properties accross the land-partitioned boundary on Hwadong silt clay loam soil (Fine clayey, mixed, mesic family of Aquic Hapludalfs), all measured data were analyzed by means of kriging, fractile diagram, smooth frequency distribution, and autocorrelation. Sampling for soil particle size distribution analysis was made at 225 intersections of $15{\times}15$ grid with 10m interval. Field capacity, bulk density and saturated hydraulic conductivity were measured in situ at 594 intersections of $33{\times}18$ grid with 2.5m interval in only $6,000m^2$ reselected from $22,500m^2$ of sampling area for particle size distribution analysis. Sampled or measured soil depths were 0 to 10cm 25 to 35cm and 50 to 60cm at each intersections. The results are summarized as follows: 1. The coefficient of variance (CV) of various physical properties ranges from 4.8 to 128.8%. Saturated hydraulic conductivity is classified into the high variation group with CV greater than 100%, while the low variation group with CV smaller than 10% consists of bulk density. Other properties belong to the medium variation group with CV between 10 and 100%. 2. The appropriate number of soil samples for the determination of various physical properties with error smaller than 10% are calculated as one for bulk density, six for field moisture capacity, 16 for silt, 19 for clay, 69 for sand and 686 for saturated hydraulic conductivity. 3. Smooth frequency distribution and fractile diagram show that saturated hydraulic conductivity is in lognormal distribution while other physical properties are in normal distribution. 4. Serial correlation analysis reveals that the soil physical properties have spatial dependence between two nearest neighbouring grid points. Autocorrelation analysis of physical properties measured between the serial grid points in the direction of south to north following section boundary shows that the zone of influence showing stationarity ranges from 7.5 to 40m. In the direction of east to west across section boundary, the autocorrelogram of many physical properties shows peaks with the periodic interval of 30m, which are similar to the partitioned land width. This reveals that the land-partitioned boundary causes soil variability.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.255-259
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• 2005

본 연구는 1981-1991년 농업과학기술원 라이시미터에서 수집한 결과를 이용하여 집중강우시 경사지 밭토양의 물유출 특성을 구명하였다. $7\~9$월 집중강우시 토양 침투수나 지표 유거수는 농업지역에서 환경으로 물질이 이동하는 주요 경로이며 특히 경사지 밭토양에서 지표 유거수는 토양유실의 주원인 중 하나이기 때문에 이에 대한 이해는 매우 중요하다. 이를 위해 강우량, 지표 유거수량, 지하 침투수량 측정 자료 중 호우주의보가 발령되는 일강우량 80mm이상일 때를 대상으로 하여 토성과 경사도에 따른 강우량과 유거수, 침투수의 관계를 분석하였다. 강우량이 적을 때 강우에 대한 침투수와 유거수의 비율은 강우시 표토의 토양수분함량에 많은 영향을 받는다. 이는 표토의 토양수분함량에 따라 유출 또는 침투 발생 유효강우량이 결정되기 때문이다. 강우량이 적을 때의 유거수량과 침투수량을 판단하기 위해 범용토양유실예측공식(Universal soil loss equation, USLE)에서는 0.5 inch 즉, 12.5 mm 이상의 강우를 유출에 대한 유효강우로 가정하고 있으며 많은 모형에서 토양의 침투속도, 포장용수량, 강우시점의 토양수분함량의 함수로 유출 또는 침투 유효강우량을 산정하고 있다. 그러나 강우량이 클 때는 강우에 대한 침투수와 유거수에 비율에 토양수분함량이 미치는 영향이 비교적 적기 때문에 토양의 수분함량에 대한 고려없이 강우와 침투수, 유거수에 대한 관계를 평가하는 것이 가능하였다. 경사도 $10\%$, 경사장 15m, 피복작물 콩인 양토를 기준으로 할 때 강우량과 침투수의 관계는 $I_{10}(mm)=0.44R(mm)+5.8(r^2=0.55)$이었다. y절이 발생한 이유는 이전 강우에 의해 침투되고 있는 물이 있음을 함축하며 기울기 0.40은 강우의 $40\%$가 지하로 침투하였음을 의미한다. 침투수량은 토성별로 양토를 1.0으로 기준할 때 사양토가 1.12로 가장 컸고, 식양토 0.94, 식토 0.91로 평가되었다. 이는 토성간의 침투속도 및 투수속도의 경향이 반영된 것이다. 경사에 따라서는 경사도가 증가할수록 지수적으로 감소하였으며 $10\% 경사일 때를 기준으로 $I(mm)=I_{10}{\times}1.17{\times}e^{-0.0164s(\%)}$로 나타났다. 같은 조건에서 강우량과 유거수의 관계는 $Ro_{10}(mm)=5.32e^{0.11R(mm)}(r^2=0.69)$로 나타났다. 이는 토양의 투수특성에 따라 강우량 증가에 비례하여 점증하는 침투수와 구분되는 현상이었다. 경사와 토양이 같은 조건에서 나지의 경우 역시 $Ro_{B10}(mm)=20.3e^{0.08R(mm)(r^2=0.84)$로 지수적으로 증가하는 경향을 나타내었다. 유거수량은 토성별로 양토를 1.0으로 기준할 때 사양토가 0.86으로 가장 작았고, 식양토 1.09, 식토 1.15로 평가되어 침투수에 비해 토성별 차이가 크게 나타났다. 이는 토성이 세립질일 수록 유거수의 저항이 작기 때문으로 생각된다. 경사에 따라서는 경사도가 증가할수록 증가하였으며 $10\% 경사일 때를 기준으로 $Ro(mm)=Ro_{10}{\times}0.797{\times}e^{-0.021s(\%)}$로 나타났다.

• Journal of Korea Water Resources Association
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• v.42 no.2
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• pp.149-160
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• 2009

The objective of this study is to suggest parameter regionalization scheme which is integrated two multivariate statistical methods: principal components analysis(PCA) and hierarchical cluster analysis(HCA). This technique is to apply semi-distributed rainfall-runoff model on ungauged catchments. 7 catchment characteristics (area, mean altitude, mean slope, ratio of forest, water content at saturation, field capacity and wilting point) are estimated for 109 mid-sized sub-basins. The first two components from PCA results account for 82.11% of the total variance in the dataset. Component 1 is related to the location of the catchments relevant to the altitude and Component 2 is connected with the area of these. 103 ungauged catchments are clustered using HCA as the following 6 groups: Goesan 23, Andong 6, Imha 5, Hapcheon 21, Yongdam 4, Seomjin 44. SWAT model is used to simulate runoff and the parameters of the model on the 6 gauged basins are estimated. The model parameters were regionalized for Soyang, Chungju and Daecheong dam basins which are assumed as ungauged ones. The model efficiency coefficients of the simulated inflows for these three dams were at least 0.8. These results also mean that goodness of fit is high to the observed inflows. This research will contribute to estimate and analyze hydrologic components on the ungauged catchments.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1213-1218
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• 2004

인류의 발전을 주도하였던 수자원은 현대에 이르러 음용수, 공업용수, 농업용수 등의 사용목적을 가지고 활용되는 한편 하천, 호수 등 자연환경과 어우러져 인간의 삶을 윤택하게 해주는 기능을 동반하여 다양한 형태로 활용되기에 이르렀다. 그러나, 수요 증가에 따른 개발증가로 수자원 부존량을 점차적으로 저하시키고 있고, 산업의 발전에 부가되는 환경 오염 등의 영향으로 현재 활용이 가능한 수자원의 양은 점차 줄어들고 있는 추세이다. 직접유출량이 발생하는 포장 면적이 증가할수록 침투가 가능한 면적이 줄어들어, 강우시 발생하는 다량의 수자원을 활용하지 못하고 하천으로 방류하게 되므로 점차 수자원 부족 현상이 가시화되고 있는 현 시점에서는 적극적인 활용 대책의 마련이 반드시 필요한 실정이다. 이와 같은 이유로 미국, 일본, 유럽 등 선진국에서는 빗물을 받아 활용할 수 있는 빗물이용시설에 대한 연구와 실제 적용을 통해 수자원의 효율적 활용을 유도하고 있으면, 국내의 경우 1990년대 중반부터 유출저감시설 연구 및 시범지역 적용을 시작으로 현재 빗물이용시설을 포함하는 연구가 활발하게 진행되고 있다. 빗물이용시설은 활용 면적에 따라서 건물의 옥상면을 통하여 유출되는 빗물을 저류하여 활용하는 방식과, 일정 면적에 내리는 빗물을 침투-저류하여 활용하는 두 가지의 방식으로 크게 구분 할 수 있다. 본 연구에서는 두 가지 방법 중, 유역 침투-저류 방식을 이용한 빗물이용시설에서의 강우강도에 따른 유출량 및 저류량 변화를 분석하고 아울러 침투-저류 방식을 활용하는 경우, 수질 변화를 검토하는 실험을 통하여 유역 저류-침투방식을 활용한 빗물이용시설의 적용성 여부를 확인하고자 한다.적법의 불확실도 $5\%\~10\%$에 비교하여 $5\%$ 내외의 정확도 수준을 지니고 있어 정확도 향상을 기대할 수 있다. 경제적인 측면에서도 매년 측정사업에 소요되는 비용과 비교하였을 때 장기적으로는 경제적인 방법이 될 수 있다. 하천수 등의 상호 관계 분석을 통해 장기간의 유역 물순환체계 변화를 분석할 수 있었다.골풀과, 닭의장풀과가 각 1종씩으로, 조사지점( I )보다 좀 더 많은 종이 분포하는 것으로 조사되었다. 또한 어류는 조사지점( I )에서 3회에 걸쳐 총 396개체가 채집되어 3목 8과 21종이었다. 이 중 한국 고유종은 11종이었고, 외래 어종은 검정우럭과 2종이 조사되었으며, Zacco platypus(피라미), Zacco temmincki(갈겨니), Acheilongnathus koreanus(칼납자루), Odontobutis platycephala(동사리), Coreoleuciscus splendidus(쉬리) 순으로 분포하고 있었고, Acheilognathus signifer(묵납자루)는 댐 건설 전에는 많이 분포하였으나 현장조사에서 서식을 확인 할 수 언어 개체수의 큰 감소내지 멸종된 것으로 추정되었다.에서 동시에 시행하였다. 수술 후 1년 내 시행한 심초음파에서 모든 환아에서 단지 경등도 이하의 승모판 폐쇄 부전 소견을 보였다. 수술 후 조기 사망은 없었으며, 합병증으로는 유미흉이 한 명에서 있었다. 술 후 10개월째 허혈성 확장성 심근증이 호전되지 않아 Dor 술식을 시행한 후 사망한 예를 제외한 나머지 6명은 특이 증상 없이 정상 생활 중이다 결론: 좌관상동맥 페동맥이상 기시증은 드물기는 하나