• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.429-434
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• 2007

This study was conducted to estimate site productivity of Quercus acutissima and Quercus mongolica by four forest climatic zones. We used site environmental variables (28 geographical and pedological factors) and site index as a site productivity indicator from nation-wide 23,315 stands. Based on multiple regression analysis between site index and major environmental variables, the best-fit multivaliate models were made by each species and forest climatic zone. Most of site index prediction models by species were regressed with seven to eight factors, including altitude, relief, soil depth, and soil moisture etc. For those models, three evaluation statistics such as mean difference, standard deviation of difference, and standard error of difference were applied to the test data set for the validation of the results. According to the evaluation statistics, it was found that the models by climatic zones and species fitted well to the test data set with relatively low bias and variation. Also having above middle of site index range, total area of productive sites for the two Quercus spp. estimated by those models would be about 6% of total forest area. Northern temperate forest zone and central temperate forest zone had more productive area than southern temperate forest zone and warm temperate forest zone. As a result, it was concluded that the regressive prediction with site environmental variables by climatic zones and species had enough estimation capability of forest site productivity.

• Magazine of the Korean Society of Agricultural Engineers
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• v.27 no.1
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• pp.62-70
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• 1985

The purpose of this study is to investigate the basic data such the total, the daily maximum, and the peak stage of consumptive use of water and also the soil moisture extraction pattern for irrigation plan of tobacco during the growing period. The plots at which this study was conducted are divided into three fertilization levels of 30g, 60g, and 90g. Each block for three levels is divided as vinyl mulching and irrigation plot, vinyl mulching and nonirrigation plot, and nonmulching and irrigation plot. The results obtained are summarized as follows: 1. The evapotranspiration amount of mulching-irrigation plots are similar to that of mulching-nonirrigation plots. While, the evapotranspiration amount of mulching plots are different obviousely from that of nonmulching plots. Therefore, a significance was recognized between the mulching plots and the nonmulching plots. 2. The amount of evapotranspiration in case of 60g and 90g fertilization level was larger than that of 30g. But the 60g plots and the 90g plots showed little differences. 3. In the total amount of evapotranspiration for each of the experimental plots during the growing period, nonmulching-irrigation plot showed the largest value of 332.9mm, second the mulching-irrigation plot, 284. 9mm, and the mulching-nonirrigation plot, the smallest as 255. 9mm. 4. In the monthly average amount of evapotranspiration for each of the treatment plots, the mulching-irrigation the mulching-nonirrigation, and the nonmulching-irrigation plot showed 3. 6mm, 3. 2mm and 4. 2mm respectively. The daily maximum amount of evapotranspiration showed 5. 1mm, 4. 5mm, and 6.4mm for the mulching-irrigation, the mulching-nonirrigationl, and the nonmulching-irrigation plot respectively. 5. It was confirmed that the higher correlationship exists between the weight of dried leaves and the amount of evapotranspiration, and between the weight of dried leaves and the coefficient of evapotranspiration with the function of logarithms. The coefficient of evapotranspiration have a tendency to increase in proportion to the leaf area index. 6. The maximum coefficient of evapotranspration and the largest leaf area index showed 1. 45 and 5.5 respectively. The stage appeared maximum values was assumed to be before and after flowering. 7. The soil moisture extraction pattern has changed by the depth of root zone for the tobacco's growing. The soil moisture extraction influenced on the 20cm depth of soil after 15 days passed, the 30cm depth after 25 days passed and the whole root zone after 45 days passed from planting. It was shown in the only mulching-irrigation plot after S5days passed from planting that the rate of soil moisture extraction of 20cm layer was larger than that of 10cm layer.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.140-140
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• 2019

본 연구에서는 Terra MODIS 위성자료와 Tensorflow를 활용해 1 km 공간 해상도의 토양수분을 산정하는 알고리즘을 개발하고, 국내 관측 자료를 활용해 검증하고자 한다. 토양수분 모의를 위한 입력 자료는 Terra MODIS NDVI(Normalized Difference Vegetation Index)와 LST(Land Surface Temperature), GPM(Global Precipitation Measurement) 강우 자료를 구축하고, 농촌진흥청에서 제공하는 1:25,000 정밀토양도를 기반으로 모의하였다. 여기서, LST와 GPM의 자료는 기상청의 종관기상관측지점의 LST, 강우 자료와 조건부합성(Conditional Merging, CM) 기법을 적용해 결측치를 보간하였고, 모든 위성 자료의 공간해상도를 1 km로 resampling하여 활용하였다. 토양수분 산정 기술은 인공 신경망(Artificial Neural Network) 모형의 딥 러닝(Deep Learning)을 적용, 기계 학습기반의 패턴학습을 사용하였다. 패턴학습에는 Python 라이브러리인 TensorFlow를 사용하였고 학습 자료로는 농촌진흥청 농업기상정보서비스에서 101개 지점의 토양수분 자료(2014 ~ 2016년)를 활용하고, 모의 결과는 2017 ~ 2018년까지의 자료로 검증하고자 한다.

• Journal of Forest and Environmental Science
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• v.26 no.2
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• pp.117-129
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• 2010

The present study was undertaken in moist temperate forest of Mandal-Chopta area in the Garhwal region of Uttarakhand, India. The aim of the present study was to assess the physical properties of soils in relation to the forest structure and composition. Twelve forest types according to the altitude, slope aspect and species compositions were selected for the study. Physical properties of soil i.e., soil colour, soil texture (per cent of sand, silt and clay), moisture content, water holding capacity, porosity, bulk density (gm/$cm^3$) and void ratio were analyzed for three different depths viz., (i) 'upper' (0-10 cm), (ii) 'middle' (11-30 cm) and (iii) 'lower' (31-60 cm) in all the selected forest types. Phytosociological and diversity parameters viz. total basal cover ($Gha^{-1}$), stem density ($Nha^{-1}$), tree species richness, Simpson concentration of dominance and Shannon-Wiener diversity index were also calculated for each forest type. This study also provides the comparisons between the results of physical analysis of the present study with numerous other previous studies in the temperate Himalayan region of the Uttarakhand.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.300-306
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• 2014

To recycle coal bottom ash(denoted here as CBA) generated from thermal power plants as a functional construction material, artificial soil(denoted as AS) containing CBA with dredged soil(denoted as DS) at a ratio(wt%) of 70 : 30 was manufactured by means of material engineering with sintering in a rotary kiln at $1125^{\circ}C$ using a green body formed via extrusion processing. The properties of the soil mechanics of the AS and the as-received CBA were analyzed and compared. Compaction testing results determined an optimum moisture content of the AS and CBA at 18%. During these tests, the maximum dry unit weights of the materials were similar, at 1.57 and 1.58 $t/m^3$, respectively. The compressive strength levels of the AS and CBA concrete specimens were 5.1 and 5.4 $t/m^3$, respectively, both of which increased after materials engineering processing. In a consolidation test, the compression index of the AS and CBA was found to be $0.114{\pm}0.001$ in both cases. The values were similar regardless of the materials engineering processes, but during the consolidation of AS, its coefficient was higher than that of the CBA materials.

• Journal of the Korean Geotechnical Society
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• v.31 no.4
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• pp.13-18
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• 2015

Considering dredged ground is consolidated more than one meter, Compression index prediction is very important. But, UD-sampling and consolidation test are impossible because of high moisture content and weak shear strength. This paper demonstrates the compression index relation, $C_{c(d)}=F(e_d,C_c)$, between in-situ and dredged clay using N. Keith Tovey's Omega point and soil physical properties. Good relationship is confirmed between proposed formula and measured primary consolidation result on dredged ground in The Republic of Korea.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.446-446
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• 2022

본 연구에서는 MODIS(MODerate resolution Imaging Spectroradiometer) 다중 위성영상을 기반으로 전국 시공간 토양수분 및 토양수분 기반의 가뭄지수 SWDI(Soil Water Deficit Index)를 산정하였다. 시공간 토양수분의 산정을 위해 입력자료로 MODIS 위성의 지표면온도(Land Surface Temperature, LST), 증발산 및 식생(Enhanced Vegetation Index, EVI; Fraction of Photosynthetically Active Radiation, FPAR; Leaf Area Index, LAI; Normalized Difference Vegetation Index, NDVI) 관련 산출물 자료와 지상 관측자료인 일 단위 강수량 자료를 구축하였다. MODIS 위성영상은 산출물별로 제공되는 QC(Quality Control) 영상을 활용해 보정을 수행하였고, 공간 강수량 자료는 기상청에서 제공하는 전국 92개 지점의 종관기상관측자료를 구축하여 공간보간기법인 역거리가중법을 적용해 생성하였다. 실측 토양수분은 농촌진흥청에서 제공하는 76개 지점의 토양 깊이 10 cm에 설치된 TDR(Time Domain Reflectomerty) 센서에서 측정된 토양수분 자료를 활용하였으며, 토양수분 모의 시 토양 속성을 고려하기 위해 국립농업과학원에서 제공하는 토양도를 구축하여 활용하였다. 토양수분 산정 모형은 다중선형회귀모형(Multiple Linear Regression Model, MLRM)을 활용하였으며, 계절 및 토성에 따른 회귀식을 산정하였다. 회귀식 기반의 토양수분과 토성별 포장용수량 및 영구위조점 값을 이용하여 SWDI를 산정하고, 실제 가뭄 발생 시기 및 지역과의 비교하고자 한다.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.878-886
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• 2011

The soybean is one of the oldest cultivated crops in the world. Microwave remote sensing is an important tool because it can penetrate into cloud independent of weather and it can acquire day or night time data. Especially a ground-based polarimetric scatterometer has advantages of monitoring crop conditions continuously with full polarization and different frequencies. In this study, soybean growth parameters and soil moisture were estimated using polarimetric discrimination ratio (PDR) by radar scatterometer. A ground-based polarimetric scatterometer operating at multiple frequencies was used to continuously monitor the soybean growth condition and soil moisture change. It was set up to obtain data automatically every 10 minutes. The temporal trend of the PDR for all bands agreed with the soybean growth data such as fresh weight, Leaf Area Index, Vegetation Water Content, plant height; i.e., increased until about DOY 271 and decreased afterward. Soil moisture lowly related with PDR in all bands during whole growth stage. In contrast, PDR is relative correlated with soil moisture during below LAI 2. We also analyzed the relationship between the PDR of each band and growth data. It was found that L-band PDR is the most correlated with fresh weight (r=0.96), LAI (r=0.91), vegetation water content (r=0.94) and soil moisture (r=0.86). In addition, the relationship between C-, X-band PDR and growth data were moderately correlated ($r{\geq}0.83$) with the exception of the soil moisture. Based on the analysis of the relation between the PDR at L, C, X-band and soybean growth parameters, we predicted the growth parameters and soil moisture using L-band PDR. Overall good agreement has been observed between retrieved growth data and observed growth data. Results from this study show that PDR appear effective to estimate soybean growth parameters and soil moisture.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.4
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• pp.294-300
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• 1983

This study was aimed at finding out the effect of soil conditioners on soil structural properties, soil water movements and soil losses. Sandy loam and silt loam soils were treated with two different kinds of soil conditioners, hydrophobic Bitumen 0.4% or hydrophilic Uresol 0.6%, and then various physical characteristics of the treated and untreated aggregates were determined. The results are summarized as follows: 1. By the soil conditioner treatment, Bitumen 0.4% or Uresol 0.6%, the aggregate stability was increased to 1.650-3.450 as compared to 0.275-0.417 of untreated soil and the sedimented bulk density was decreased. 2. Air-water permeability ratio of sandy loam was decreased to 2.2 by Uresol treatment as compared to untreated soil 3.8. In case of silt loam, it was decreased to 6.9 and 5.3 by Bitumen and Uresol treatment as compared to untreated 9.4, and water permeability of treated soil continued high value for 40 days. 3. Air-water permeability ratio was sharply enhanced as the structure instability index increased, but the ratio increased very smoothy after the index over 1. 4. The soil moisture retention was increased 2 to 6% by Uresol treatment, but it was decreased 1 to 3% by Bitumen treatment.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.4
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• pp.48-58
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• 1992

This study was conducted to investigate the consolidation characteristics of the marine clay, treated with predetermined ratios of lime and briquette ash. The standard consolidation test was performed for the sample of mixture remoulded under the condition of optimum moisture content. The results obtained were as follows ; 1.The increase of the consolidation coefficient due to load increament was larger in the lime treated soil and briquette ash treated soil than in the untreated soil. The decrease of the compression index due to admixing ratio of additives was smaller in the former than in the latter. 2.The increase of the secondary consolidation coefficient of the untreated soil due to load increment was minimal, while that of lime treated soil and the lime-briquette ash treated soil was conspicuous and that of briquette ash treated soil was slight. 3.The $C\alpha$/Cc relationship of untreated soil was represented by colsely distributed points. That of briquette ash treated soil, lime treated soil and the lime-briquette ash treated soil was represented by linear distribution. The $C\alpha$/Cc values of untreated soil, briquette ash treated soil and lime treated soil were approximately 0.049, 0.044 and 0.031, respectively. 4.The maximum consolidation coefficient was obtained with lime and briquette ash (lime : briquette .h 2 :1) mixture ratio of 15%. And the minimum secondary consolidation coefficient, compression index was obtained with same mixture ratio. The required quantity of lime could be reduced and the consolidation was accelerated by applying the above mixture ratio.