• 한국토양비료학회지
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• 제48권6호
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• pp.648-657
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• 2015

Soil organic matter (SOM) plays an important role in the continuous production and environmental conservation in arable soils. In particular, the decomposition of organic matter in soil might promote soil organic matter and fertility due to the mineralization of N. In this study, to evaluate the effect of organic matter amendment on the C mineralization and N dynamic, $CO_2-C$ flux, extractable N and $N_2O$ emission were determined using closed chamber for 4 weeks at 10, 15, $20^{\circ}C$ of incubation temperature after the mixture of $2Mgha^{-1}$ rice straw compost and rye in sandy loam and clay loam. Regardless of soil texture, decomposition rates of rice straw compost and rye at $10{\sim}20^{\circ}C$ of incubation temperature ranged from 0.9 to 3.8% and 8.8 to 20.3%, respectively. Rye application in soil increased $NH_4-N$ and $NO_3-N$ content as well as the $N_2O$ emission compared to the rice straw compost. After incubation for 4 weeks, total C content in two soils was higher in rice straw compost than in rye application. In conclusion, application of rice straw compost and rye to soil was able to improve the soil organic matter and fertility. However, organic matter including the recalcitrant compounds like rice straw compost would be effective on the management of soil organic matter and the reduction of greenhouse gases in soil.

• 유기물자원화
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• 제4권1호
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• pp.33-42
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• 1996

예취빈도와 액상구비의 시용수준에 대한 Reed canarygrass의 반응을 조사하여, 잠재생산성의 증대를 위한 경제적이고 합리적인 적정 예취빈도와 액상구비의 시용수준을 추정하고자 하였다. 예취빈도별 연간 건물수량에 대한 예취번초의 상대수량은 3회 예취구에서 2번초, 4회 예취구에서 3번초 및 5회 예취구에서는 4번초에서 다른 예취번초에 비해 가장 높은 상대수량을 나타내었다. 무시용구의 연간 건물수량은 예취빈도에 따라 6.4~7.5 ton/ha의 범위를 나타내었으며, 3회 예취구에서 가장 많은 연간 건물수량을 나타내었다. 액상구비의 시용수준이 증가됨에 따라서 연간 건물수량은 증가되었다. 즉, 3회 예취구에서는 연간 180 kg, 4회 예취구에서는 연간 120 kg 및 5회 예취구에서는 연간 300 kg로 증시하였을 때, 무시용구에 비해 유의하게 높은 건물수량을 나타내었다. 액상구비의 건물생산효율 (kg DM/kg N)은 3회 예취구의 120 kg/ha/cut, 4회 예취구의 30 kg/ha/cut 및 5회 예취구의 90 kg/ha/cut에서 각각 16.8, 25.4 및 10.4 kg 의 가장 높은 건물을 생산하였고, 시용시기에 따른 건물생산효율은 3회 예취구에서 1번초, 4회와 5회 예취구에서는 2번초에서 가장 높았다. 경제적 액상구비의 질소시용수준은 3회 예취구에서 462.7~525.3 kg/ha, 4회 예취구에서 353.1~423.2 kg/ha 그리고 5회 예취구에서 380.1~424.4 kg/ha의 범위를 나타내었다.

• 생물정신의학
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• 제3권2호
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• pp.203-210
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• 1996

알쯔즈하이머형 치매 환자의 뇌자기공명영상(腦磁氣共鳴影像)에 나타난 뇌위축(腦萎縮) 및 백질병변(白質病變)과 치매 발병연령(發病年齡)과의 상관관계(相關關係)를 밝히기 위해, NINCDS-ADRDA 진단기준(診斷基準)에 의한 조발성(早發性)(n=9) 및 만발성(慢發性)(n=18) 알쯔하이머형 치매군과 각각의 정상대조군(n=10 : n=11)에서 뇌위축(腦萎縮)은 대뇌피질위축(大腦皮質萎縮)과 뇌실확장(腦室擴張)의 체적(體積)을 계측(計測)하고 백질병변(白質病變)은 뇌실주변, 심부백질, 기저핵 및 천막하영역의 백질(白質) 신호(信號) 고강도(高剛度)의 반정량적(半定量的) 평가척도(評價尺度)로 측정하였다. 조발성(早發性) 환자군의 뇌위축(腦萎縮)은 대조군보다 유의하게 컸고(p<0.05) 백질병변(白質病變)에서는 모든 영역에서 차이가 없었으며, 만발성(慢發性) 환자군은 뇌위축(腦萎縮) 정도에서는 대조군과 차이가 없었으나 백질병변(白質病變)은 심부백질 및 시상에서 유의한 차이(p<0.05)를 보였고 나머지 모든 영역에서도 대조군보다 심한 경향을 보였다. 알쯔하이머형 치매가 (1) 뇌위축(腦萎縮)을 주로 보이고 백질병변(白質病變)은 심하지 않은 조기발병군(早期發病郡)과, (2) 백질병변(白質病變)이 두드러지고 뇌위축(腦萎縮)은 심하지 않은 만기발병군(晩期發病郡)으로 나누어질 가능성과 양군의 병태생리(病態生理)가 상이(相異)할 가능성이 시사되었다.

• 한국초지조사료학회지
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• 제20권4호
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• pp.237-242
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• 2000

This study was conducted to investigate the effects of cutting frequency on dry matter yield and nutritive value between heading and headless varieties of sorghumxsudangrass hybrid in 1998. Treatments were var. TE hay grazer(heading type) and Jumbo(headless type) as main plot, and 1, 2, and 3 cutting times per a year as sub plot. Although plant height of sorghumxsudangrass hybrid was no significant difference among treatments, headless type was very slightly higher than that of heading type, and both of variety decreased with 1, 2, and 3 cutting times in order. Also, dry matter yield of sorghum~sudangrass hybrid was no significant difference between heading and headless type. Dry matter yield of first cutting plot in heading type and in headless type was the higher than those of second and third cutting plot. Acid detergent fiber and neutral detergent fiber of headless type were slightly higher than that of heading type. Acid detergent fiber of sorghumxsudangrass hybrid was highest at first cutting plot in both varieties. Neutral detergent fiber of second cutting plot in heading type and first cutting plot in headless type were the highest respectively. In vitro dry matter digestibility of headless type was very slightly higher than that of heading type. And in vitro dry matter digestibility of second cutting plot was the highest in both varieties. In vitro digestible dry matter of sorghumxsudangrass hybrid was no significant difference among treatments. The results demonstrated that although there was not significant difference, cultivation of headless type and first cutting plot per a year were very good for nutritive value and DM yield of sorghumxsudangrass hybrid as summer forage crops in Korea. (Key words : Heading, Headless type, Cutting frequency, Sorghum X Sudangrass Hybrid)

• 한국초지조사료학회지
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• 제16권4호
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• pp.327-337
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• 1996

A field experiment was conducted at SNU Experimental Livestock Farm, Suweon in 1995 to determine effect of planting date on forage performance of wm hybrids of four different maturity groups. A split-plot design replicated three times was used, with com hybrids representing four maturity groups (115, 118, 121 and 125 days) being the main plots and planting dates (3124, 415, 415, 425, 515 and 5/15) the sub-plots. 1. Days to emergence and percent emergence from the March 24 planting were, on the average, 36 days and 58%, respectively, but those from the April 5 to May 15 planting averaged 12 days and 92%, respectively. 2. Plant and ear heights increased gradually as the dates of planting were delayed except the May 15 planting, however, percent ear was decreased as the dates of planting were delayed. There was a trend for the mean lodging percentage of the hybrids to be higher as the planting date was delayed. 3. The 115-and 118-day mediumearly maturing hybrids harvested on August 18 produced silages with a dry matter content between 27 and 30% at all planting dates except the May 15 planting, while the 121-and 125-day medium-late maturing hybrids produced silages with a dry matter wntent less than 27% regardless of any planting dates. 4. There were no significant differences in mean dry matter yield among the hybrids, but significant mean TDN yield differences were found. The 115-, 118- and 125-day hybrids had significantly higher mean TDN yield than the 121-day hybrid. There were significant differences in mean dry matter and TDN yields among the planting dates. The mean dry matter and TDN yields from the April 5, 15 and 25 plantings were significantly higher than those of other plantings, however, there were no significant differences in mean TDN yield among the April 5, April 15 and April 25 plantings. No significant planting date $\times$ maturity interactions were found for both the dry matter and TDN yields. 5. Mean stover NDF and ADF contents of the 115- and 118day hybrids were higher than those of the 121- and 125-day hybrids, but the reverse was true for mean stover IVDMD and RFV. Mean stover NDF an ADF contents increased with earlier plantings, but mean stover IVDMD and RFV increased when planting was delayed. Results of this experiment indicate that for corn planting in central and northern areas of Korea, early to mid-April may be the right time with the 115-to 118-day maturity hybrids when silage making before August 20 is taken into consideration.

• 한국환경과학회지
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• 제5권2호
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• pp.243-252
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• 1996

미국 New Jersey주에서 채취한 4종류의 토양사료를 이용하여 토양에서 카드뮴 흡착과 치환성양이온의 탈착에 미치는 pH와 유기뮬함령의 영향을 조사하였다. 카드뮴용액으로는 $1\times10^{-5}$M,$1\times10^{-4}$M, $2\times10^{-4}$M, $3\times10^{-4}$M ${Cd(NO_3)}_2$ 용액을 사용하였고, 흡착평형시의 토양용액의 pH는 4.0,5.5, 7.0, 8.5로 맞추었다. 카드뮴흡착등온선의 기울기는 토양용액의 pH가 증가하였으며, partition coefficient($K_4$)도 용액의 pH가 증가할수록 크게 증가하였다. 또한 Langmuir흡착방정식에 의하여 구한 카드뮴대흡착량도 용액의 pH가 높은 경구가 낮은 경우보다 훨씬 많았다. $1\times10^{-4}$M ${Cd(NO_3)}_2$ 용액을 사용한 실험에서 유기물함량과 partition coefficient사이의 correltion coefficient($r^2$)는 용액의 pH가 4.0인 경우의 0.3027에서 pH가 8.5인 경우의 0.9964로 증가하였으며, $2\times10^{-4}$M ${Cd(NO_3)}_2$ 용액을 사용한 실험에서는 pH가 4.0인 경우의 0.2093에서 pH가 8.5인 경우의 0.9657로 증가하였다. 칼슘과 마그네슘의 탈착량은 토양용액의 pH가 증가할수롱, 흡착된 카드뮴의 양이 증가할수록 감소하였다.

• 한국환경농학회지
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• 제39권1호
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• pp.65-74
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• 2020

BACKGROUND: Soil carbon sequestration has been investigated for a long time because of its potential to mitigate the greenhouse effect. No- or reduced tillage, crop rotations, or cover crops have been investigated and practiced to sequester carbon in soils but the roles of soil biota, particularly microorganisms, have been mostly ignored although they affect the amount and stability of soil organic matters. METHODS AND RESULTS: In this study we analyzed the organic matter and microbial community in organically cultivated corn field soils where no-tillage (NT) or conventional tillage (CT) had been practiced for about three years. The amounts of organic matter and recalcitrant carbon pool were 18.3 g/kg dry soil and 4.1 g C/kg dry soil, respectively in NT soils, while they were 12.4 and 2.5, respectively in CT soils. The amounts of RNA and DNA, and the copy numbers of bacterial 16S rRNA genes and fungal ITS sequences were higher in NT soils than in CT soils. No-tillage treatment increased the diversities of soil bacterial and fungal communities and clearly shifted the bacterial and fungal community structures. In NT soils the relative abundances of bacterial phyla known as copiotrophs, Betaproteobacteria and Bacteroidetes, increased while those known as oligotrophs, Acidobacteria and Verrucomicrobia, decreased compared to CT soils. The relative abundance of a fungal phylum, Glomeromycota, whose members are known as arbuscular mycorrhizal fungi, was about two time higher in NT soils than in CT soils, suggesting that the higher amount of organic matter in NT soils is related to its abundance. CONCLUSION: This study shows that no-tillage treatment greatly affects soil microbial abundance and community structure, which may affect the amount and stability of soil organic matter.

• 한국산업보건학회지
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• 제27권1호
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• pp.70-76
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• 2017

Objectives: This on-site study was performed to evaluate the reduction efficiency of an air cleaner on particulate matters and biological agents in a swine facility. Materials and Methods: Particulate matter was measured using a real-time monitoring recorder and biological agents were sampled with a one-stage impactor and then analyzed based on the microbial culture method. An experimental process for the reduction effect on airborne pollutants through air cleaner operation consisted of three conditions: no treatment, wet scrapper by water spray and wet scrapper by disinfectant spray. Results: Geometric mean levels of particulate matter(TSP, $PM_{10}$, $PM_{2.5}$ and $PM_1$) were presented at $1,608{\mu}g/m^3$, $1,373.8{\mu}g/m^3$, $401.8{\mu}g/m^3$ and $144.5{\mu}g/m^3$ for no treatment; $1,503{\mu}g/m^3$, $1,017{\mu}g/m^3$, $159.4{\mu}g/m^3$ and $69.8{\mu}g/m^3$ for wet scrapper by water spray; and $1,222.17{\mu}g/m^3$, $477.17{\mu}g/m^3$, $33.2{\mu}g/m^3$ and $11.1{\mu}g/m^3$ for wet scrapper by disinfectant spray, respectively. In the case of biological agents, the geometric averaged concentrations of total airborne bacteria and fungi were as follows: $45,371cfu/m^3$ and $13,474cfu/m^3$ for no treatment, $43,286cfu/m^3$ and $8,610cfu/m^3$ for wet scrapper by water spray, and $2,440cfu/m^3$ and 1,867 cfu/ for wet scrapper by disinfectant spray, respectively. Regardless of particulate matter and biological agent, the highest concentrations were found for no treatment, while the lowest concentrations were found with wet scrapper by disinfectant spray. Conclusions: Based on the results obtained from this on-site evaluation, there was a significant reduction effect on particulate matter and biological agents through the application of an air cleaner in this study.

• 대한불안의학회지
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• 제16권2호
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• pp.57-75
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• 2020

Particular matter is steadily increasing due to environmental factors at domestic and abroad such as industry and economy. Recently, the exposure particular matters has been reported to increase the risk not only for morbidity and mortality, but also for diseases of the respiratory system, cardiovascular system and central nervous system/neuropsychiatric disorder. Although the causes of neuropsychiatric diseases are genetic and environmental factors, it is necessary to pay more attention to environmental factors in terms of prevention. We mainly describe environmental factors that affect neuropsychiatric disorders, mainly on particular matter, which is one of harmful environmental substances. In the current study, we reviewed evidence for the presence of particular matter or particular matter related harmful air pollutants-O₃, SO₂, NO₂/NOx, traffic related air pollution, that may represent risk factors for the development of neuropsychiatric disorder.

• Asian-Australasian Journal of Animal Sciences
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• 제7권2호
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• pp.231-237
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• 1994

Three concentrations of P (0.33, 0.43 and 0.54%) and two concentrations of Ca (0.60 and 0.97%) in ration dry matter were evaluated for effects on dry matter intake and on milk yield and composition using 24 Holstein cows. Cows were arranged in a $3{\times}2$ factorial experiment as an incomplete randomized block design with three 28-day periods. Each cow consumed at least one ration with each concentration of Ca. Dry matter intake, yield of 3.5% Fat Corrected Milk, and milk composition were not affected by concentration of P, but milk yield was greater when lowest concentration of P was fed (22.8 vs. 22.1 kg/day; p<0.07). Cows fed rations containing 0.60% Ca had greater milk (22.7 vs. 21.9 kg/day; p<0.02) and 3.5% Fat Corrected Milk yields (p<0.03) and slightly greater protein content than when fed 0.97% Ca. Dietary Ca:P ratios between 1.1:1 and 2.9:1 had no effect on dry matter intake, milk yield, or composition. Concentrations of P in plasma were within the normal range for all rations. Because cows had high dry matter intake, mean daily intakes of both P and Ca were greater than required for their level of milk yield.