• Agricultural and Biosystems Engineering
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• 제6권1호
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• pp.15-21
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• 2005

This study was conducted to develop a nondestructive grouping system for soil organic matter using visible (VIS) and near infrared (NIR) spectroscopic method. The artificial light was irradiated on the cut soil surface at 15 to 20 cm depths to reduce the errors of light at open field. The reflectance energy from the cut soil surface was measured to group the soil organic matter using VIS/NIR light sensor with narrow band pass filter. From reflectance spectra of soil samples, the sensitive wavelengths for measuring the soil organic matter were selected and compared to previous research results. The grouping system for soil organic matter consisted of light sensor with band pass filter measuring the reflectance energy of the cut soil surface, global positing system (GPS), analog-to-digital (AD) converter, computer and operating software. The regression models to predict the soil organic matter were developed and evaluated. From field test, the accuracies of the developed light sensor system were 81.3% for five-stage grouping of the soil organic matters and 91.0% for three-stages grouping of the soil organic matters, respectively. It could be possible to support the decision making for variable rate applications with the developed grouping system for soil organic matter in precision agriculture.

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2418-2426
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• 2022

The grouping analysis is a method guided by the Korea Radioactive Waste Agency for efficient analysis of radioactive waste for disposal. In this study, experiments to verify the adequacy of grouping analysis were conducted with radioactive soil, concrete, and dry active waste in similar environments. First, analysis results of the major radionuclide concentrations in individual waste samples were reviewed to evaluate whether wastes from similar environments correspond to a single waste stream. As a result, the soil and concrete waste were identified as a single waste stream because the distribution range of radionuclide concentrations was "within a factor of 10", the range that meet the criterion of the U.S. Nuclear Regulatory Commission for a single waste stream. On the other hand, the dry active waste was judged to correspond to distinct waste streams. Second, after analyzing the composite samples prepared by grouping the individual samples, the population means of the values of "composite sample analysis results/individual sample analysis results" were estimated at a 95% confidence level. The results showed that all evaluation values for soil and concrete waste were within the set reference values (0.1-10) when five-package and ten-package grouping analyses were conducted, verifying the adequacy of the grouping analysis.

• 한국식물병리학회지
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• 제13권1호
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• pp.37-45
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• 1997

Disease incidence (DI), pre-emergence damping-off (PDO), days until the first symptom appeared (DUS), disease progress curve (DPC), and area under disease progress curve (AUDPC) were investigated in vivo after sowing ginseng seeds in each of 37 ginseng-cultivated soils which were sampled from 4 regions in Korea. Non linear fitting parameters, A, B, K and M, were estimated from the Richards' function, one of the disease progress models, by using the DI at each day from the bioassay. Inter- and intra-relationships between disease variables and stand-missing rate (SMR) in fields were investigated by using the simple correlation analysis. Disease variables of the root rot were divided into two groups: variables related to disease incidence, e.g., DI, AUDPC and A parameter, and variables related to disease progress, e.g., B, K and M parameters. DI, AUDPC, and DUS had significant correlations with SMR in ginseng fields, and then it showed that the disease development in vivo corresponded with that in fields. Soil samples could be separated into 3 and 4 groups, respectively, on the basis of the principal component 1 (PC1) and the principal component 2 (PC2), which were derived from the principal component analysis (PCA) of Richards' parameters, A, B, K and M. PC1 accounted for B, K and M parameters, and PC2 accounted for A parameter.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1996년도 사용종료 매립지의 안정화 에 관한 국제 세미나
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• pp.1-40
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• 1996

In order to determine the proper treatment of the finished landfill, it is important to predict the trend and stability of the major sources of contaminant in the landfill. In this paper the fate of contaminant sources in the landfill is studied from various literatures by grouping the contaminants into waste, leachate, and landfill gas. One example site referred is Nanji landfill which is one of the representative finished landfills in our country and the trend of contaminant sources in this landfill at current stage is discussed.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.163-166
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• 2003

In this study, a grouping of particle-size distributions(PSDs) by means of the fuzzy c-means clustering method(FCM) was presented. The classification was performed with the whole and the major soil series representing pedological origin. In case of the major soil series, PSDs were clustered as $2{\sim}4$ groups and the characteristics of clustering results were quite different between the soil series. It was found that the characteristics of PSDs at center of each class can be explained by formation process of each soil series. In case of whole soil data, PSDs were classified to 8 classes in which 4 classes were single mode and 4 classes were bimode distributions. Through this study, it is concluded that pedogenetic process is a plausible explanation for grain size distribution of soils.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권6호
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• pp.57-65
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• 2017

Six soil subsampling methods were evaluated with explosive compounds-contaminated soils to quantify the variance associated with each method. The methods include modified grab sampling, simplified ripple splitting, fractional shoveling, coning & quatering, degenerate fractional shoveling, and rolling & quatering. All the methods resulted in significantly lower CV (coefficient of variation) of 1~5%, compared to common grab sampling that gave 8~98% of CV, possibly due to the reduction of grouping and segregation errors described by Gy sampling theory. Among the methods, simplified ripple splitting tends to result in lower explosive compounds concentrations, while the rolling & quatering gave the opposite result. Fractional shoveling method showed the least variance and the highest reproducibility in the analysis.

• 한국식물병리학회지
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• 제13권1호
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• pp.46-56
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• 1997

Based on the principal component analysis (PCA) of Richards' parameter estimates, ginseng field soils were grouped as the principal component 1 (PC1) and the principal component 2 (PC2). The microflora and physico-chemical characteristics of each soil group were compared to elucidate soil environmental factors affecting the disease development of root rot of ginseng seedling. Among 3 soil groups by PC1, there were differences in the populations of total fungi (TF) and Cylindrocarpon plus Fusarium (C+F), and the population ratio of Cylindrocarpon plus Fusarium to total fungi or total bacteria (C+F/TF, C+F/TB) in rhizoplane of ginseng seedlings, the population of total actinomycetes (TA) and the population ratio of total Fusarium to total actinomycetes (Fus/TA) in soil, and soil chemical properties (EC, NO3-N, K, Mn, ect.). Among 4 soil groups by PC2, there were differences in TF, C+F, TB, C+F/TF and C+F/TB in the rhizoplane, Trichoderma plus Gliocladium (T+G) in soil, and P2O5 content in soil. Especially, EC, NO3-N, K, K/Mg and Mn were positively correlated to PC1, and TA was negatively to PC1; however, TF, C+F, TB, C+F/TF and C+F/TB in the rhizoplane were significantly correlated to PC2 positively. On the other hand, microbes in the rhizoplane were not significantly correlated to the stand-missing rate (SMR), although TA and Fe/Mn were negatively correlated, and pH and Ca were positively correlated to SMR.

• 한국조경학회지
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• 제27권1호
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• pp.122-131
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• 1999

Indoor environments are usually less than optimal for the growth of ferns, especially in regards to the water condition. These studies were performed to investigate responses involved in causing growth of ferns and presume management plan against the water deficit under indoor conditions. The effect of air humidity and soil moisture on the ferns was examined in Adiantume raddianum and Selaginella kraussiana. Results of experiments are as follows; 1. Under a low humidity condition, having a 25-50% RH. ornamental value of ferns decreased much more than under a 90% RH. Under a low soil moisture, such as sand treatment, ornamental value of ferns also decreased. 2. Leaf chlorophyll content, water content and stomata situations increased as air humidity and soil moisture went up. 3. Even if air humidity and soil water were not enough for ferns growth, the extending of irrigation cycle was helpful. 4. Under extremely low air humidity conditions, some water management, namely, using water holding soil or extending of irrigation cycle was desirable. Other methods of increasing air humidity, including water instruments such as ornamental pools, waterfalls, or fountains, grouping plants together were also helpful. But spraying water on leaves increased injury to ferns growth because of excess evaporation from the leaves. Though these studies, we learn that ferns are susceptible to water condition such as air humidity, soil water and water management. If other environmental factos are maintained with optimal conditions, water condition plays an important role in ferns growth in indoor environments.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권6호
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• pp.1-9
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• 2011

A bibliographical review of Gy sampling theory for particulate materials was conducted to provide readers with useful means to reduce errors in soil contamination investigation. According to the Gy theory, the errors caused by the heterogeneous nature of soil include; the fundamental error (FE) caused by physical and chemical constitutional heterogeneity, the grouping and segregation error (GE) aroused from gravitational force, long-range heterogeneous fluctuation error ($CE_2$), the periodic heterogeneity fluctuation error ($CE_3$), and the materialization error (ME) generated during physical process of sample treatment. However, the accurate estimation of $CE_2$ and $CE_3$ cannot be estimated easily and only increasing sampling locations can reduce the magnitude of the errors. In addition, incremental sampling is the only method to reduce GE while grab sampling should be avoided as it introduces uncertainty and errors to the sampling process. Correct preparation and operation of sampling tools are important factors in reducing the incremental delimitation error (DE) and extraction error (EE) which are resulted from physical processes in the sampling. Therefore, Gy sampling theory can be used efficiently in planning a strategy for soil investigations of non-volatile and non-reactive samples.

• 한국토양비료학회지
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• 제19권4호
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• pp.283-289
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• 1986

논토양(土壤)에 수도(水稻)를 포함(包含)하여 그 전후작(前後作)으로 밭작물(作物)을 다모작(多毛作) 할 경우에 토양종류별(土壤種類別) 적성정도(適性程度)를 추정(推定) 할 수 있는 논토양다모작적성등급(土壤多毛作適性等級)을 구분(區分)코자 기초시험(基礎試驗)을 실시(實施)하고 적성등급구분(適性等級區分) 기준(基準)을 설정(設定)하였다. 기초시험결과(基礎試驗結果)는 전보(前報)에서 논(論)하였고 구분기준(區分基準) 및 주요결과(主要結果)는 다음과 같다. 1. 적성등급(適性等級) 구분요인(區分要因)은 잠재생산력을 대표(代表)한 토성(土性) 및 배수등급(排水等級), 화학적특성(化學的特性)(표토염농도(表土鹽濃度), 및 심토(心土)의 반응(反應)), 환경조건(環境條件)(경사도(傾斜度) 및 온량지수(溫量指數)) 그리고 지하수위(地下水位) 및 토양모재(土壤母材) 등(等)을 선택(選擇)하여 연역(演繹) 귀납(歸納) 절충식(折衷式) 인자별가중치(因子別加重値) 상승(相乘) 상가복합법(相加複合法)에 의한 이론적(理論的) 최상치(最上値)가 100 점(點)이 되도록 하였다. 91 점이상(點以上)인 토양(土壤)을 I급지(級地)로 하고 60 점이하(點以下)인 토양(土壤)을 V급지(級地)로 하되 10 점(點) 단위(單位)로 등분(等分)하였으며 등급별(等級別) 제한인자(制限因子)는 "물리성(物理性)" "화학성(化學性)" 및 "경사도(傾斜度)" 등(等) 3가지로 하되 2개까지 병기 가능(可能)토록 하였다. 2. 온량지수(溫量指數) 110 이상(以上)인 대부분(大部分)의 영남지역(嶺南地域)은 I급지(級地)가 19%, II급지(級地) 22.7%, III급지(級地) 44.7%, IV급지(級地) 11.5% 그리고 V급지(級地)가 2.1%로서 전국(全國)의 논토양(土壤) 급지별(級地別) 분포비율(分布比率)보다는 상급지비율(上級地比率)이 약간 높았다. 3. 토양별(土壤別) 총득점(總得點)과 생산력지수간에는 유의성(有意性)($r=.922^{**}$)이 인정(認定)되어 기준(基準)의 적합도(適合度)가 높은 것으로 볼 수 있었다.