• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.210-213
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• 2011

In this study, growth of pepper seedlings was tested by treating organic materials in a plastic green house in Ssangok-ri Dogok-myeon, Hwasun-gun, Jeollanam Province from February 3, 2010 to April 19, 2010. The raised seedlings were planted to the organic planting area with an interval of $70cm{\times}55cm$ on April 20 in Deogam-ri Gogeum-myeon Wando-gun and red peppers were harvested at 7 times from July 22 to September 29. Before planting, the plant length of the overgrowth of seedlings was reduced by 26.8% using plant powder treatment as compared to the control group. The red pepper yield was 27% higher than in the control group when 20g of bone ash powder and 20g of plant powder were mixed. The yield tended to increase in other treatments compared to the control group.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.218-221
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• 2011

To improve the soil properties of physical and microbial community rice bran and wood charcoal were applied in the continuously cultivated plastic film house soil. Soil physical properties were improved by application of rice bran and charcoal compared to chemical fertilizer application (control) by 8~14% in bulk density and 5~9% in soil porosity. Changes in the biological ratio indexes of fatty acids in the soils were detected depending on the inputted materials. Especially in application of rice bran including mixture with charcoal, much more fungi and less bacteria were detected and the ratio of fungi to bacteria was increased, suggesting the more organic carbon metabolically active in these treatments. The high ratio of aerobe to anaerobe suggested the better aerobic conditions were in the soil inputted wood charcoal. From these results, it is important and possible to select some materials for the organic pepper cultivation, which may improve the poor condition soil.

• Toxicological Research
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• v.35 no.4
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• pp.343-351
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• 2019

Many in vitro developmental toxicity assays have been proposed over several decades. Since the late 1980s, we have made intermittent attempts to introduce in vitro assays as screening tests for developmental toxicity of inhouse candidate products. Two cell-based assays which were developed two decades apart were intensively studied. One was an assay of inhibitory effects on mouse ascites tumor cell attachment to a concanavalin A-coated plastic sheet surface (MOT assay), which we studied in the early days of assay development. The other was an assay of inhibitory effects on the differentiation of mouse embryonic stem cell to beating heart cells (EST assay), which we assessed more recently. We evaluated the suitability of the assays for screening in-house candidates. The concordance rates with in vivo developmental toxicity were at the 60% level. The EST assay classified chemicals that inhibited cell proliferation as embryo-toxic. Both assays had a significant false positive rate. The assays were generally considered unsuitable for screening the developmental toxicity of our candidate compounds. Recent test systems adopt advanced technologies. Despite such evolution of materials and methods, the concordance rates of the EST and MOT systems were similar. This may suggest that the fundamental predictivity of in vitro developmental toxicity assays has remained basically unchanged for decades. To improve their predictivity, in vitro developmental toxicity assays should be strictly based on elucidated pathogenetic mechanisms of developmental toxicity.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.513-517
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• 2022

An investigation of the severe destruction of wood ear mushroom (Auricularia auricula-judae), which were commercially cultivated in a plastic house in Hwabuk-myeon, Jeju-si, South Korea from April to August 2021, revealed a tenebrionid beetle subsequently identified as Platydema takeii Nakane, 1956 (Coleoptera: Tenebrionidae: Diaperinae). To the best of our knowledge, this is the first report of a tenebrionid species infesting commercially cultivated mushrooms in South Korea. The damage symptoms and diagnosable characteristics of adults and larvae of P. takeii are provided in this study.

• Journal of Korea Soil Environment Society
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• v.5 no.3
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• pp.77-85
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• 2001

This study was carried out to show the groundwater quality in the shallow aquifer at the plastic film houses area near livestock areas in Kyong=n river. The study was conducted at 31 sites in Pogok Myon. Yongin City, Kyonggi Province on March, June and August in 1998, Medium value of CO $D_{cr}$ by survey months was as follows ; June(8.0mg/L) > April(4.4mg/L) > August(3.2mg/L). And the value of $NH_3$-N showed same tendency ; June (0.21mg/L) > April(0.08mg/L) > August (0.04mg/L). In case of nitrate- nitrogen, the changes by survey months were shown similar. But 28% of survey sites exceeded to agricultural groundwater quality reference level(20mg/L). And sulfur concentrations at some survey sites exceeded the reference level(50mg/L). But the other items of water quality were shown to suitable level for agriculture. The result showed that groundwater quality management should be taken for agricultural using at the livestock and plastic film house areas.

• Journal of Bio-Environment Control
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• v.8 no.1
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• pp.49-55
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• 1999

This study aims at analyzing environment factors of two tier cropping systems and suggesting effective structures of two tier cropping systems. The environment factors in two tier cropping systems are temperature, relative humidity, solar radiation, temperature of nutrient solution, and wind velocity. Especially, The most important factors are the solar radiation and the solar incident area between the two tiers. During the experiment, observations were made of the two levels in the plastic greenhouse. The highest temperatures were 38.3$^{\circ}C$ in the top level and, 35.5$^{\circ}C$ in the bottom level, respectively. The temperature of the nutrient solution between the two levels showed little difference. The relative humidity in the top level was 60~7o% and that in the bottom 65~80%, exhibiting that the bottom is approximately 10% higher. Change of photosynthetic photon flux density and solar radiation both have a tendency to be similar. The wind velocities for both levels were recorded at 0.1m.s$^{-1}$ in the afternoon and 0.05m.s$^{-1}$ in the evening. The solar incident areas in the bottom level increased by approximately 25% at an East-West position and 17.7% at a South-North position, respectively.

• Korean Journal of Environmental Agriculture
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• v.5 no.2
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• pp.141-148
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• 1986

The blue-light effect on the grown as well as on the physiological activity of some major horticultural plants in Korea has been investigated. The light quality used for the work was obtained from sunlight filtered by an orangecolored polyethylene film which removed about 70% of visible light in the spectral region of $350㎚{\sim}500㎚$. The film was developed in this laboratory especially for the work and named BCR film meaning blue color-removing film. The light environment in the plastic house which was built with BCR film provided plants with the blue color-deficient sunlight. Thus, the photobiological effect of blue light could be examined conversely by comparing with the effect of white sunlight in a conventional plastic house built with colorless polyethylene film. In a sense of applicability to horticulture, two remarkable effects of the blue color-deficient sunlight on plant physiology were observed: First, it enhanced to a great extent the growth activity of plants-pepper, cucumber, zucchini, tomato, and leaf lettuce at the vegetative stage as well as at the reproductive stage, as demonstrated by their yield which were in average $40{\sim}50%$ increased compared with the control (under white sunlight). Second, it improved significantly the cold tolerance of plants, as exhibited with their resistance to chilling during treatment in a cold chamber maintained at a temperature which caused chilling injury to the plants of control. The visualized effects were reflected on the physiological activity of cells on organelle level. Chloroplast isolated from the plant leaves grown under BCR film showed considerably stronger photosynthetic activity, as judged by the increased electron transport rate of illuminated chloroplast, than that from leaves grown under white PE film. Mitochondria from leaves grown under BCR film maintained normal respiration activity until temperature decreased to a few degree($^{\circ}C$) lower than the temperature which caused respiratory inhibition to mitochondria obtained from leaves of the control.

• Korean Journal of Poultry Science
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• v.46 no.4
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• pp.215-221
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• 2019

This study investigated the effects of various stocking densities on the growth performance of Korean native ducks. Twelve hundred day-old ducklings were reared for 50 days in a duck house (windowless, plastic wire-floor pen). Two weeks later, 852 of these ducks (350±30 g) were selected for at least 80% uniformity per stocking treatment (six treatments, four replications/treatment, depending on a stocking density of 4~9 birds m^-2). Experimental diets were corn-soybean-based and broiler ducks were grouped based on age [0~21 days of age (CP 21%, ME 2,900 kcal/kg) and 21~50 days of age (CP 17%, ME 3,100 kcal/kg)]. Body weight (BW) did not significantly differ among different aged treatment groups (P>0.05); however, uniformity decreased with higher stocking densities (P<0.05). Feed intake and feed conversion ratio of ducks aged 42~50 days significantly decreased in the T4-6 treatments compared with the T1-3 treatments (P<0.05). In all experimental periods, BW gain was not significantly different among treatments, but feed intake decreased significantly as the stocking density increased (P<0.05), and feed conversion ratio was significantly different among six treatments with stocking density (P<0.05). In conclusion, we found that the stocking density of Korean native ducks in a plastic wire-floor pen was approximately 7 birds m^-2 in consideration of productivity and uniformity.

• Korean Journal of Plant Resources
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• v.37 no.4
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• pp.392-400
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• 2024

This study was conducted to find the flowering and growth characteristics according to the different altitudes (plains and mid-mountain regions) and cultivation methods (field and plastic houses cultivation) of Elsholtzia splendens. Experimental regions located at 12 meters and 500 meters above sea level were selected for the plains and the mid-mountain, respectively, and the same method was applied for cultivation management by different altitudes and cultivation methods. In the mid-mountain region, flower bud emergence (2-3 days), flowering (9 days), and full bloom (6-7 days) stages of Elsholtzia splendens were earlier than in the plains, and field cultivation was earlier than plastic house cultivation. The plant height, the main stem diameter, and the number of branches tended to increase gradually after an initial rapid growth at 59 to 69 days after planting date. The days of duration of sunshine (less than 8 hours) from the rainy season (June 20) to the period when vegetative growth increases gradually (59 to 69 days after planting) was 22 to 29 days and 26 to 35 days in the plains and the mid-mountain regions respectively, and this period was estimated time of transition from vegetative growth to reproductive growth. The spikes growth of Elsholtzia splendens by cultivation altitudes was higher in the mid-mountain region than in the plains, and there were no statistically significant differences in growth characteristics except for the main stem diameter, the number of branches, and the dry matter. Also, the amount of flowering and growth was higher in the plastic house cultivation compared to the field cultivation. As a result, some differences in flowering amount were observed when cultivating Elsholtzia splendens for landscaping purposes, but it was considered possible to cultivate in both plains and mid-mountain regions. This study therefore provides ecological information for understanding the relationship between weather characteristics and growth of Elsholtzia splendens.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.344-352
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• 2012

Soil physical properties determine soil quality in aspect of root growth, infiltration, water and nutrient holding capacity. Although the monitoring of soil physical properties is important for sustainable agricultural production, there were few studies. This study was conducted to investigate the condition of soil physical properties of arable land according to land use across the country. The work was investigated on plastic film house soils, upland soils, orchard soils, and paddy soils from 2008 to 2011, including depth of topsoil, bulk density, hardness, soil texture, and organic matter. The average physical properties were following; In plastic film house soils, the depth of topsoil was 16.2 cm. For the topsoils, hardness was 9.0 mm, bulk density was 1.09 Mg $m^{-3}$, and organic matter content was 29.0 g $kg^{-1}$. For the subsoils, hardness was 19.8 mm, bulk density was 1.32 Mg $m^{-3}$, and organic matter content was 29.5 g $kg^{-1}$; In upland soils, depth of topsoil was 13.3 cm. For the topsoils, hardness was 11.3 mm, bulk density was 1.33 Mg $m^{-3}$, and organic matter content was 20.6 g $kg^{-1}$. For the subsoils, hardness was 18.8 mm, bulk density was 1.52 Mg $m^{-3}$, and organic matter content was 13.0 g $kg^{-1}$. Classified by the types of crop, soil physical properties were high value in a group of deep-rooted vegetables and a group of short-rooted vegetables soil, but low value in a group of leafy vegetables soil; In orchard soils, the depth of topsoil was 15.4 cm. For the topsoils, hardness was 16.1 mm, bulk density was 1.25 Mg $m^{-3}$, and organic matter content was 28.5 g $kg^{-1}$. For the subsoils, hardness was 19.8 mm, bulk density was 1.41 Mg $m^{-3}$, and organic matter content was 15.9 g $kg^{-1}$; In paddy soils, the depth of topsoil was 17.5 cm. For the topsoils, hardness was 15.3 mm, bulk density was 1.22 Mg $m^{-3}$, and organic matter content was 23.5 g $kg^{-1}$. For the subsoils, hardness was 20.3 mm, bulk density was 1.47 Mg $m^{-3}$, and organic matter content was 17.5 g $kg^{-1}$. The average of bulk density was plastic film house soils < paddy soils < orchard soils < upland soils in order, according to land use. The bulk density value of topsoils is mainly distributed in 1.0~1.25 Mg $m^{-3}$. The bulk density value of subsoils is mostly distributed in more than 1.50, 1.35~1.50, and 1.0~1.50 Mg $m^{-3}$ for upland and paddy soils, orchard soils, and plastic film house soils, respectively. Classified by soil textural family, there was lower bulk density in clayey soil, and higher bulk density in fine silty and sandy soil. Soil physical properties and distribution of topography were different classified by the types of land use and growing crops. Therefore, we need to consider the types of land use and crop for appropriate soil management.