• Korean Journal of Agricultural Science
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• v.8 no.2
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• pp.203-211
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• 1981

Mechanization of rice transplanting operation is very important project not only to solve the labor shortage problem at the so-called labor demand peak seasons of the rice transplanting, but also to reduce the production cost of rice by reducing the labor requirements. For these reasons this study was carried out to find the basic data for encourage the project of mechanization of rice transplanting. 381 sample farms were surveyed with questionaries and interviewed with a considerable number of relative personels about the operation, selecting and ownership trend of the rice transplanter. Collected data was analized by computer of Chungnam National University computer center applied to frequencies, cross- tabulation, $x^2$-test. The analized results of this survey are summarized as follows; 1. About 76.09% of the farmers interviewed was individual ownership of rice transplanter but about 52.27% of the farmers who wanted to purchase it in 2 or 3 years supported the cooperative ownership and utilization. This fact suggested that cooperative system of village level should be thoroghly studied. 2. The 93.33% of respondents gave the answer that the yield of rice was not affected by the planting methods between machine and manual. 3. The farmers who had a rice transplanter owned 4- row type rice transplanter with mat type seedling but the 25% of the farmers wanted to purchase it in 2 or 3 years wanted to own a 4 row type rice transplanter with band type seedling. Therefore the introduction of the 4-row type rice transplanter with band type seedling to rural area should be considered again. 4. The percent of farmers who wanted the cooperative system of village level was 49.57-57.83% of the farmers who had it already and wanted to own it in near future. It was strengthened by this fact that seedling nursely work was technically supported by the governmental level.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.969-980
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• 2016

This experiment was conducted to assess changes to the chemical properties of soil and applicability in a case of rice cultivation with organic fertilizers. The investigator applied organic fertilizers to rice cultivation for five years to examine changes to the chemical properties of soil and found that the experiment group of organic fertilizers made an ongoing increase in pH, organism content, and available phosphate content annually compared with the control group with no big differences according to the amounts of organic fertilizers used. As for the yield components, there were no statistical differences in the number of spikelets and grain filling rate between the experiment group of organic fertilizers and the control group. The experiment group recorded a higher level in 1,000 seeds weight and yield than the control group. Experiment Group 4 recorded the highest level at 29.11 kg of 1,000 seeds weight. Experiment Groups 3 and 4, which used 222 kg and 267 kg per 10 a, respectively, recorded 576 kg and 572 kg of yield, respectively, which were 4.7% and 4.1% higher than 549 kg of control group, respectively. As for the quality of brown rice, there were no statistical differences in the head rice percentage between the control and experiment group, both of which were in the range of 83.2-85.7%. As for the protein content, Experiment Groups 3 and 4, both of which used a lot of organic fertilizers, were in the range of 6.9-7.1%, which was lower than 7.5% of control group. Those findings indicate that the long-term application of organic fertilizers can improve the chemical properties of soil and increase the yield more than the conventional method of fertilizer application. The findings also suggest that it will be effective to apply 222 kg of organic fertilizers or more per 10 a.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.209-214
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• 2006

One hundred Individuals that were collected from plains and mountains all around South Korea were used for this experiment. The inhibition abilities of lipid peroxidation by Artemisia spp. collections were compared with BHT (butylated hydroxytoluene). The results could be confirmed the excellency fur control of lipid peroxide level such as BHT 200 ppm in all mugwort collections. Antioxidant activity (AEAC), electron donating ability (EDA), total phenolic compound, and flavonoids of 100 Artemisia spp. collections were analyzed. Total phenolic compound contents of Artemisia spp. collections were ranged from 156 to 1,767 rng/100 g, and mugwort collections with more than 900 mg/100 g of total phenolic compound content were 20 individuals. Electron donating abilities were ranged from 13.4 to 95.0%, and mugwort collections over 90% of electron donating ability were 23 individuals. Antioxidant activity of ethanol extracts that used ABTS and DPPH radical were measured and mugwort collections with high total phenolic compound contents had high radical exclusion ability as well. Artemisia spp. collections, AC-60, AC-67, AC-77, that showed the high levels of antioxidant activities and had good growth characters and productivity, were selected for mass production.

• Journal of Mushroom
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• v.5 no.1
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• pp.1-6
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• 2007

A new commercial strain "Hambak" of Grifola frondosa was developed by di-mono crossing between dikaryon of ASI 9031 and monokaryotic strain derived from ASI 9021. It can be cultivated in plastic bottle and bag filled with oak and poplar sawdust substrate which supplemented with 15% rice bran or 10% corn bran. Improvement of cultivation methods was required for shortage of mycelium incubation period and management of humidity in growing room. The optimum temperature of mycelial growth was $25^{\circ}C$ and that of fruiting body development was $15{\sim}18^{\circ}C$. The color of pileus surface was brown and fine pores, whitish to cream-colored, were underside. Primordia formation of Hambak was two days faster than that of Yipsae 1. The yield was $97g/850m{\ell}$ bottle, a bunch of fruiting body was bigger and the quality was better than Yipsae 1.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.3
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• pp.212-220
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• 2005

One hundred eleven glutinous rice collections from seven countries were evaluated for genetic diversity based on agronomic traits and RAPD analysis. Twelve agronomic traits including yield components amy-lose content, alkali digest value were used to clarify the genetic relationships among glutinous rice collections. Glutinous rice collections were classified into 4 groups and early maturings Korean landraces and high amylose indica belonged to group I with RAPD analysis, 15 primers selected for polymorphic bands generated 117 bands and 81 bands $(69.2\%)$ showed polymorphism. The number of amplified bands per primer ranged from 5 to 11, with the average number of bands of 7.8. With the similarity value of 0.78 in dendrogram derived from the cluster analysis based on RAPDs, glutinous rice collections were classified into 9 groups. Seventy-seven percent of the collections were classified into group I that is the largest one, while the others $(23\%)$ were distributed to group Il-IX. Group I included most indica type rices and early ripening collections, while the small groups of III-IX included most of the Korean collections.

• Journal of Plant Biotechnology
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• v.45 no.1
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• pp.17-29
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• 2018

This study was conducted to investigate a morphological trait in 294 rice accessions including Korean breeding lines. We also carried out a genome-wide association study (GWAS) to detect significant single nucleotide polymorphism markers and candidate genes affecting major agronomic traits. A Manhattan plot analysis of GWAS using morphological traits showed that phenotypic and statistical significance was associated with a chromosome in each group. The significance of SNPs that were detected in this study was investigated by comparing them with those found previously studied QTL regions related to agronomic traits. As a result, SNP (S8-19815442), which is significant with regard to leaf angle, was located in the known QTL regions. To observe gene mutations related to leaf angle in a candidate gene, Os08g31950, its sequences were compared with sequences in previously selected rice varieties. In Os08g31950, a single nucleotide mutation occurred in one region. To compare relative RNA expression levels of candidate gene Os08g31950, obtained from GWAS analysis of 294 rice accessions and related to lateral leaf angle, we investigated relative levels by selecting 10 erect leaf angle varieties and 10 horizontal leaf angle varieties and examining real-time PCR. In Os08g31950, a high level of expression and various expression patterns were observed in all tissues. Also, Os08g31950 showed higher expression levels in the erect leaf angle variety group and higher expression rates in the leaf than in the root. The candidate gene detected through GWAS would be useful in developing new rice varieties with improved yield potential through future molecular breeding.

• Journal of the Korea Institute of Building Construction
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• v.18 no.1
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• pp.25-31
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• 2018

In this study, the Controlled Low Strength Material (CLSM) was investigated to utilize the bottom ash and fly ash generated in the Circulating Fluidized Bed Combustor (CFBC). It was confirmed that the CFBC fly ash (CFBC-F) and CFBC bottom ash (CFBC-B) had an irregular particle shape through SEM measurement. According to the results of the hazard analysis, it was also confirmed that they were environmentally safe. In the case of mixing with CFBC-F, the unit quantity was increased. Regarding the rate of change of length, shrinkage in the range of -0.05~0.50% occurred in the air dry curing condition and expansion in the range of 0.1~0.6% in the sealed curing condition. Compressive strength was increased in the sealed curing condition compared to the air dry curing condition because there was enough moisture for hydration reaction in the long term. Therefore, the results of this study are likely be used as basic research data of mine filler materials.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.319-323
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• 2009

Strawberry is an out-crossed crop that is relatively sensitive to inbreeding, and as a result, most of breeding programmes in strawberry have been based on selection breeding where elite parents are selected from intercrossing. Also, pedigree breeding has been successfully employed in a number of instances to concentrate genes of interest. Therefore, in order to obtain inbred line having the genotype of excellent combining ability by selfing and incrossing to improve breeding efficiency of strawberry, elite varieties were self-pollinated. From the selfing line of "Benihoppe" cultivar, we selected "Wongyo 3111" having excellent horticultural traits such as plant vigor, sugar content and fruit hardness among these progenies. "Wongyo 3111" shows erect plant type, vigorous growth habit, early flower bud differentiation with 16~17 flowers per cluster. Fruits of "Wongyo 3111" are conical type having a bright red skin color, and 17.2 g in an average weight. Also that have a relatively more high sugar/acid ratio and firmness than check cultivars as sugar content of 11.3oBx, acidity of 0.50% and firmness of 21.7 g/$mm^2$. But although yield of "Wongyo 3111" is not significantly different from check cultivars, its marketable yield is remarkably lower than that of check cultivars because of poor fruit-setting under low temperature. Disease and pest reactions of "Wongyo 3111" are more sensitive to powery mildew, anthracnose and spotted spider mites than check cultivars. Therefore, "Wongyo 3111" is suitable for intermediate parent line better than as a cultivation cultivar.

• Journal of Energy Engineering
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• v.27 no.4
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• pp.64-69
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• 2018

The purpose of this study is to expand the use of coal ash and coal slag in thermal power plants. In addition, controlled low strength materials was developed to prevent mine settlement. Bottom ash and KR slag are mixed at ratio of 7:3 to expand the use of industrial by-products through carbonate reaction and inhibit the exudation of heavy metals. In order to efficiently fill the abandon mine, workability and physical properties were evaluated according to flow. As a result of elution of harmful substance experiment, it was confirmed that the carbonation reaction inhibited the elution of heavy metals. It was confirmed that the difference in water ratio was the difference in specific surface area of the controlled low strength materials. It was confirmed that the working efficiency is excellent when the flowability is 300mm compared to 260mm. compressive strength measurement result was relatively high at 260mm compared to 300mm because the number of pores due to decrease of water ratio was small.

• Korean Journal of Weed Science
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• v.5 no.2
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• pp.202-210
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• 1985

Requirements in weed control in a mulberry field are much similar to those in orchards, but also feature a longer period of weed control of various kinds of persistent weeds, i.e., spring, summer, and winter annuals as well as perennials. In addition the mulberry tree is relatively more sensitive to herbicide injury. Hence, very few herbicides have been used in mulberry field. The present study was conducted to evaluate the usefulness of oxyfluorfen in comparison with alachlor and simazine, which are registered for ordinary mulberry field in Korea, for weed control efficacy in the new, rapidly increasing practice of transparent polyethylene-film mulched and densely planted younger mulberry culture. Dominant spring weeds were Galium spp., Erigeron spp., Polygonum senticosum, and Chenopodium spp. in the non-mulched interbed area in contrast to the Digitaria spp. and Potulaca spp, under mulch. Dominant summer weeds were Digitaria spp., Portulaca spp., Erigeron spp., Artemisia spp. and Calystegia japonica in the non-mulched interbed area while weeds did not occur significantly during summer under mulch which were shaded by vigorously growing mulberry trees. The weeds occurred under mulch in spring reduced shoot growth of young mulberry tree resulting in the reduced yield of mulberry leaves for silkworms. The weeds occurred in the interbed area did not affect until May, but interfered later summer- and fall-growth of mulberry tree. Early single spring application of alachlor(EC), simazine(WP) or oxyfluorfen(EC) at a rate of 650 g, 750 g or 350 g ai per ha, respectively, controlled most annuals satisfactorily to fall in the mulched bed area. In the nonmulched interbed area, however, thrice does of alchlor or simazine was necessary for satisfactory control of spring weeds, followed by summer application of alachlor or simazine at twice dose level as tank mixture with paraquat at 490 g ai per ha for satisfactory control of summer to fall weeds. Single spring application of oxyfluorfen at a rate of 1400 g ai per ha was persistently effective to control satisfactorily even summer and fall weeds. However, heavy rainfall splashed soil borne oxyfluorfen to the lower branch leaves causing some leaf burns. Spring application of oxyfluorfen at a rate of 350 g ai per ha followed by summer application of oxyfluorfen and paraquat tank mixture (350 g ai + 490 g ai) was the best choice for the non-mulched interbed area weed control among the treatments.