• Journal of Ecology and Environment
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• v.47 no.4
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• pp.282-289
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• 2023

Background: As wildlife habitats are being destroyed and growth environments are changing, the survival of animals and plants is under threat. Epilobium hirsutum L., a species that inhabits wetlands, has held legally protected status since 2012. However, no specific measures are currently in place to protect its habitat, leading to a decline in remaining populations as a result of land use change and human activities. Results: The growth environment (including location, climate, land use, soil, and vegetation) of the five habitat sites (Samcheok, Taebaek1, Taebaek2, Cheongsong, Ulleung) of E. hirsutum L. was investigated and analyzed. These habitats were predominantly situated in flat areas with gentle south-facing slopes, at an average altitude of 452.7 m (8-726 m) above sea level in Gangwon-do and Gyeongsangbuk-do. The average annual temperature ranged 11.5℃ (9.2℃-12.9℃), whereas the average annual precipitation ranged 1,304.5 mm (1,062.7-1,590.7 mm). The surrounding land use status was mainly characterized by mountainous areas, and human interference, such as agricultural land and roads, was commonly found in proximity to these natural habitats. Soil physicochemical analysis revealed that the soil was predominantly sandy loam with a slightly high sand content. The average pH measured 7.64, indicating an alkaline environment, and electrical conductivity (EC) averaged 0.33 dS/m. Organic matter (OM) content averaged 66.44 g/kg, available phosphoric acid (P₂O₅) content averaged 115.73 mg/kg, and cation exchange capacity (CEC) averaged 23.43 cmolc/kg. The exchangeable cations ranged 0.09-0.43 cmol⁺/kg for potassium (K), 10.23-16.21 cmol⁺/kg for calcium (Ca), 0.67-4.94 cmol⁺/kg for magnesium (Mg), and 0.05-0.74 cmol⁺/kg for sodium (Na). The vegetation type was categorized as E. hirsutum community with high numbers of E. hirsutum L., Persicaria thunbergii (Siebold & Zucc.) H. Gross, Phragmites japonica Steud., Humulus japonicus (Siebold & Zucc.), and Bidens frondosa L.. An ecological flora analysis, including the proportion of lianas, naturalized plants, and annual herbaceous plants, revealed that the native habitat of E. hirsutum L. was ecologically unstable. Conclusions: Analysis of the habitat of E. hirsutum L., a class II endangered wildlife species, provided essential data for local conservation and restoration efforts.

• Journal of dental hygiene science
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• v.16 no.1
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• pp.93-100
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• 2016

The purpose of this study was to compare the changes of retentive force in different stud attachment systems for implant retained overdenture. Two commercially available attachments with different retentive forces were investigated: Kerator (pink, blue, red) and O-ring (orange, red). Two implant fixtures were vertically embedded in base mountings. Five pairs of each attachment were evaluated. A universal testing machine was used to evaluate the retentive force of two attachments during wear simulation. Surface characteristics of each attachment system were evaluated with scanning electron microscopy. Five pairs of each attachment were evaluated. Kerator pink showed the highest initial retention. After 2,500 cycles of wear-simulation, Kerator pink noted the largest decrease in retention. According to results of surface analysis, Worn surfaces were obtained in matrices and patrices. Heavy wears were observed in matrices. After 2 year-wear simulation, most attachments exhibited retention loss. Attachments using different kind of material exhibited dissimilar surface alterations.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.2
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• pp.146-157
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• 1994

Wasong(Orostachys japonicus A. Berger) has been used as anti-cancer medicinal plants from ancient time. This experiment was conducted to obtain some fundamental informations concerning anatomical study, germination test, soil analysis of indigenious districks, adaptaion of soil for wasong. The leaf of wasong was xerotype with spine, mesophyl chloroplast is dense surrounded vascular bundle, with a many large water storage tissue without chloroplast, and was bifacial stomata leaf type. The stem of wasong was amphicribral vascular bundle, central cylinder was cylinder type and protostele. Root was polarch type, potoxylem of it's was arranged in ring shape of annulation and metaxylem. The structure of flower was cymose, was caylyx of 5 sepals, corolla of 5 petals, roecium of 10 stames, ovules of five, placentation parietal, ovary superior, axile placenta. The optimum temperature for seed germination was $25^{\circ}C$ under light and germination percentage was 22.5%. Dormancy breaking was effective for 6-8 days at 5$^{\circ}C$ and at 100 ppm level of $GA_3$ The soil analysis of wasong local districks, content of available $P_2O_5$, Ca were higer than optimal level of upland and C.E.C., exchangeable k was not significantly different of that, but exchangeable magnesium was very low. The growth of wasong was affected draining regardless soil combination treatment.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.1
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• pp.38-46
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• 2002

Chrysanthemum boreale M. (hereafter, C. boreale M.), a perennial flower, has been historically used as a natural medicine in Korea. With increasing concerns for health-improving foods, the demand for C. boreale M. has become higher than ever. Howevr, the amount of wild C. boreale M. collected from mountainous areas is not enough to cover all demands. The cultivation system and fertilization strategy are required to meet increasing demand on C. boreale M. with a good quality. We investigated the effects of nitrogen application on plant growth and effective components of C. boreale M. to suggest optimum rate of nitrogen fertilization. C. boreale M. was cultivated in a pot scale (1/2000a scale), and nitrogen applied with rate of 0(N0), 50(N50), 100(N100), 150(N150), 200(N200), and $250(N250)kg\;ha^{-1}$. Phosphate and potassium were applied at the same level ($P_2O_5-K_2O=80-80kg\;ha^{-1}$) in all treatments. Maximum yield achieved in 246 and $226kg\;ha^{-1}$ N treatment on the whole plant and the flower part, a valuable part as a herbal medicine, respectively. Proline was the most abundant amino acid in the flower of C boreal M. and the contents of amino acids increased with increasing nitrogen application rate in flower. Nitrogen recovery efficiency was high more than 41% in all nitrogen treatments and increased to 61.8% in nitrogen N100 treatment. From the nitrogen content, the high nitrogen uptake, the low residue of mineral N and the reasonably good apparent fertilizer recovery, it can be inferred that C. boreale M. made efficient use of the available nitrogen. In flower, contents of Cumambrin A. which is a sesquiterpene compound and has the effect of blood-pressure reduction, decreased with increasing nitrogen application. However, the amount of Cumambrin A in flower increased as nitrogen rate increased, because of increasing flower yield. Conclusively, nitrogen fertilization could increase yields and enhance quality. The optimum nitrogen application rate might be on the range of $225{\sim}250kg\;ha^{-1}$ in a mountainous soil.

• Journal of Korean Society of Forest Science
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• v.35 no.1
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• pp.1-8
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• 1977

Forest soil fertility was evaluated through the approach of numerical method. In this study, the soil chemical properties analyzed for 35 different soil series as table 2 were cited in numerical analysis. Minimum contents of essential nutrients in the surface soil for a satisfactory growth of tree in the plantation were evaluated by comparing with Wild's standard as table 1. Demanding level of fertilization were evaluated by using the formula 1 as table 5. Similar relation of soil chemical properties between soil series were calculated through formula 2, and then classified into 5 groups in soil chemical properties. 1. General chemical properties of surface soil in case of 35 soil series. About 40 percent of 35 different soil series are less than 2 percent in organic matter, 10 ppm in available phosphorus, 1.25m.e/l00g in exchangeable calcium and 0.5m.e/l00g in exchangeable magnesium. Generally, shortage of exchangeable potash are not found. CEC less than 10m.e/l00g are in two thirds and strong acid soil less than PH 5.5 are in about four fifths. 2. Soil series requested or not the fertilization are indirectly evaluated from the formula 1 using the relative figure of chemical components of CEC, OM and MgO. Through this analysis, 8 different soil series have very poor quality in soil chemical capacity so that demands highly the fertilization. On the other hand, other 13 different soil series group have not been thought to need the fertilization according to chemical guality. 3. By the results comparing the similarity of chemical properties of forest soil, it is thought to be suitable that the forest soil fertility are divided into 5 groups as follows: 1. Low CEC soil 1-1 Low organic matter soil less than 2 percent 1-2 Medium organic matter soil less than 4 percent 2. High CEC and organic matter soil 2-1 Low magnesium soil 2-2 High magnesium soil 3. High magnesium and calcium soil as lime stone.

• Korean Journal of Medicinal Crop Science
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• v.6 no.2
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• pp.131-136
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• 1998

This experiment was carried out to investigate the effect of several organic fertilizers on the growth and root yield of Achyranthes japonica N. from 1995 to 1996. Four organic fertilizers were applied: rice straw manure (RSM), fermented rice straw manure (FRSM), mixed oil cake manure (MOCM) and mighty soil manure (MSM). Organic matter, available phosphate, $K_2O$, CaO, and MgO of soil increased in all plots with the addition of organic fertilizers, specifically with MOCM application. The highest contents of total nitrogen were 6.16% for MOCM and the available phosphate contents were very high in all of organic fertilizers except MSM. RSM and MSM with C/N ratios of 22.5, 17.7, respectively, were easily decomposed but C/N ratios of FRSM and MOCM, which were considered as irresolvable organic fertilizers, were 40.9 and 8.4, respectively. FRSM and MOCM applications increased emergence rate and improved the growth characters of shoot and root parts of plants compared to those of N - P - K fertilization. The highest dry root yield resulted from FRSM 20% and MOCM 26% treatment. There were significantly positive correlations between the growth characters of shoot, root parts of plants and dry root yield in A. japonica grown under organic fertilizer applications.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.171-181
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• 1999

A field experiments was carried out to investigate the physicochemical properties of soil and cucumber growth in vinyl house when irrigation point was made at 0.2, 1/3, 0.5 and 1.0 bar. The obtained results was summarized as follow: The taxonomic class of the soil used was loam and each content of the required water was 4.4, 7.3, 9.6 and 13.4 mm per each irrigation time at 0.2, 1/3, 0.5 and 1.0 bar treatments in spring culture, respectively. At 0.2 bar and 1.0 bar treatments, interval of irrigation was 2.3 and 14.8 day, the times of irrigation was 37 and 6, and total irrigation volume was 163.5 and 80.3 mm, respectively. After cucumber culture, pH, EC concentration and exchangeable K content of soil at 0.2 bar treatment was distributed near to the level of improvement target while EC, available $P_2O_5$ and exchangeable base content in other treatments were higher compared to improvement target. At 1.0 bar treatment, ratios of the solid and liquid phase were 44.9 and 27.1%, respectively, and bulk density was $1.26g\;cm^{-3}$ which was the highest among the treatments. At 0.2 bar treatment, the ratio of the solid and liquid phase was 41.7 and 22.8%, respectively, and bulk density was $1.09g\;cm^{-3}$ which was the lowest. The root length and radius at 0.2 bar treatment were best, while those at 1/3 bar were worst. At 0.2 bar treatment, the total yield was 7,269 kg and the weight of good products was 5,677 kg which was the highest among treatments. At 0.33 bar treatment, the yield was the lowest with the high ratio of deformity.

• The Korean Journal of Malacology
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• v.26 no.4
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• pp.267-273
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• 2010

From January to December 2007, we have investigated sediment types, environmental factors and density of clam Ruditapes philippinarum inhabited at Oeri, Naeri, Jonghyeon and Bangmiri tidal flats in Gyeonggi Bay off the west coast of Korea. Sediment types of Oeri and Jonghyeon were characterized with well sorted muddy sand. In contrast, Bangmiri tidal flat was mainly composed of poorly sorted gravelly muddy silt and Naeri was characterized with very poorly sorted muddy-sandy gravel. During the course of study, the surface water temperature, salinity, dissolved oxygen and pH ranged 3.2 to $27.0^{\circ}C$, 21.7 to 33.3 ‰, 5.6 to 12.7 mg/l and 7.36 to 8.82, respectively. The suspended solid (SS) ranged from 3.2 to 1,266.0 mg/l and chlorophyll-a level in the water column ranged $0.3-36.1{\mu}g/l$, respectively. The density of clam in the study areas was mainly determined by the harvesting activities rather than the types of substrate. Relatively higher density of clam was observed in Oeri and Bangmiri where the clam seeds were sowed by the villagers. Condition factor of clams were found to be higher in Oeri where the substrate sorting was better with higher level of chlorophyll a. It was believed that sediment types and the level of available food the two governing factors controlling the density and growth of clam in Gyeonggi Bay.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.25-32
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• 1998

To characterize the growth environment, inorganic composition and morphological chracteristics of leaves of Korean tea plant, soil and tea leaf samples were collected from 15 locations and analyzed. The chemical characteristics of soils were in range of pH 4.09~6.15, OM 23.9~72.6g/kg, available phosphate less than 300mg/kg, K $0.8{\sim}2.5cmol^+/kg$, Na $tr{\sim}0.17cmol^+/kg$, Ca $1.0{\sim}6.2cmol^+/kg$, and Mg $0.3{\sim}2.1cmol^+/kg$. The contents of Ni. Cr, Zn. Cu, Pb, and Cd were at the level less than natural content in upland soil. Most of the sample soils were sandy loamy and loamy texture. The native tea plants were mainly grown in bamboo thicket or in forest. The leaf sizes of tea plants were $6.85{\pm}1.75{\times}2.6{\pm}0.5cm$, lateral vein number $14.2{\pm}2.7$, and crenated number $58.5{\pm}11.2$, and the leaf color was thin to dark green. The contents of $NH_4{^+}$, $Na^+$, $K^+$, $Mg^{2+}$ and $Ca^{2+}$ in tea leaves were in range of 30.5~47.7, 45.5~164.5, 16,998~25,431, 1.590~2,392 and 1,085~1,958mg/kg, respectively. The contents of $F^-$, $Cl^-$, $NO_3{^-}$, $PO_4{^{3-}}$ and $SO_4{^{2-}}$ were in range of 21.2~63.2, 126.4~257.9, 108.5~185.9, 1,270~1.819, and $954{\sim}1,670mg/kg$, respectively. The leaf size of native tea plant grown widlly in Shunchun Changchun-ri, Hwasun Ssangbongsa, Kuryoi Chonunsa, Bosong Daewonsa and Namhae Boriam was as large as those of Yabukita. Japan cultiver, grown at Kangjin Jangwon tea field.

• Korean Journal of Organic Agriculture
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• v.7 no.2
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• pp.115-124
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• 1999

This study was conducted to investigate the effects of fertigation level such as 50%, 75% and 100% N of standard amount of chemical fertilizer,m and fertigation interval such as every irrigation, intervals of 1 and 2 weeks of piggery waste water(PWW) on the growth, yield of red pepper plant and the chemical properties of soil used. In early stage, growth of red pepper plant fertigated with PWW and that of red pepper plant applicated standard chemical fertilezer was the same, while it were increased as increasing application amounts of PWW, and later growth and total yield of red pepper plant were much more at 75% N fertigation of PWW. Inorganic content such as nitrogen, phosphate and potassium and chlorophyll content of red pepper leaves were increased as increasing fergigation amount of PWW. 50% fertigation level showed the lowest rate of fruit setting of red peper plant. For soil chemical properties, pH was slightly decreased, but available $P_2O_5$, and exchangeable K content were increased as increasing fertigation amount of PWW. Because there was not statistically significant difference in the growth, the yield of red pepper and chemical properties of soil used according to various fertigation intervals, and no need to artificially supply PWW, therefore fertigation by simple automatic system with tensiometer was thought to be better.