• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.52-57
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• 2006

This research was carried out to determine the effect of controlling nitrogen application on tiller development, yield, and quality of rice under scanty or excess seedling stands in direct-seeded rice on flooded soil surface. Seedling stand was set to 3 levels: scanty $(60/m^2)$, optimum $(120/m^2)$, and excess $(200/m^2)$. In the scanty plot, additional 4 kg/10a nitrogen was applied at the 3rd leaf stage to promote tiller development. On the other hand, applying 3.3 kg/10a nitrogen at 5th leaf stage in the excess plot was omitted to suppress tillering. Maximum numbers of tillers per plant were 15.2 and 8.6 in scanty and excess plots, respectively, as compared with 9.8 in optimum plot. Productive tiller rate decreased with the increase in number of seedling stands. Regardless of seedling density, the first tiller developed on the 3rd node of rice stem from the bottom. The primary tillers developed at 3, 4, 5, 6, 7 nodes in scanty plot, 3, 4, 5 nodes in optimum plot, and 3, 4 nodes in excess plot. The secondary tillers developed only in some portion of plants in scanty and optimum plots. The order of tiller emergence was negatively correlated to stem length, panicle length, non-productive tiller number, grain number per panicle, and fertility in scanty plot, and to perfect grain ratio in excess plot. In the optimum plot, however, the order of tiller emergence was not correlated to any of the mentioned characteristics. The perfect grain ratio of scanty plot was the highest because green-kerneled rice was a very small portion in the primary tillers as compared with those of optimum and excess plots. Yield indexes of scanty and excess plots were 99%, and 97%, respectively, of the yield (494 kg/10a) in optimum plot. In conclusion, when seedling stands are not at optimum level, rice yield and quality similar to optimum planting density level can be obtained by means of controlling nitrogen application.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.3
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• pp.211-216
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• 2009

Approximately 43 million tons of livestock manure (LM) are produced each year on Korean farms. LM can be utilized as a valuable resource and/or it can contaminate water by runoff and leaching through the soil, when LM has been thoughtlessly applied to the land and directly discharged into the water. This experiment was carried out to investigate the effect of no-till system and LM application on dry matter (DM) yield of silage corn and $NO_3$-N concentration in leaching water of lysimeter installed in the experimental field. The treatments were replicated three times in split plot design. Main plots consisted of tillage systems, such as conventional tillage (CT) and no-tillage (NT). Sub plots consisted of the type of LM, such as chemical fertilizer (CF), composted cattle manure (CCM) and composted swine manure (CSM). The control plots were fertilized as commercial chemical fertilizer. DM yields of corn increased significantly in order to CF > CCM > CSM (p<0.05). DM yield of corn in CT increased as comparing with that of corn in NT. Plant height, ear height and stem diameter also increased in order to CF > CCM > CSM. In addition, the root weight in CT was increased as comparing with that of corn in NT. However, there was no interaction effects of between type of LM and tillage system. $NO_3$-N concentration in leaching water of LM application was less than 10 ppm, but $NO_3$-N concentration in CF exceeded 10 ppm which is safety level of drinking water during summer time (rainfall season).

• Korean Journal of Weed Science
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• v.2 no.1
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• pp.57-62
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• 1982

This study was conducted to evaluate the important weed occurring in orchard and to establish on effective control method using combination of non-selective foliar applied herbicide followed by soil treated herbicide. In terms of quantity, Calysregia hederacea, Artemisia princeps, Ixeris chinensis, Cephalonopios segetum, Capsella bursa-pastoris, Setaria viridis, Chenopodium album, Trifolium repens, Digitarta sanguinalis in order were observed to be the most important weeds in May, In July the most dominant weeds were D. sanguinalis, Setaria viridis, Amaranthus lividus, Portulaca oleracea, Polygonum hydropiper, Acalypha australis, Artemlsia prtnceps, Miscanthus sinensis in order, showing D. sanguinalis to be the dominant species. D. sanguinalis was one single dominant species till autumn, followed by A. lividus, P. oleracea, A. australis. Simpson's index, 0.159 obtained in May just before herbicide application increased to 0.253 in July and again decreased to 0.233 in Sept. in the oxyfluorfen treated plot, meaning that no specific weed species were dominant, while in the untreated plot, D. saguinalis was relatively single dominant species, showing Simpson's index, 0.540 and this trend was mainained till autumn. The most effective herbicide to control D. sanguinalis and other annuals was oxyfluorfen at 0.47kg a.i./ha. when applied at preemergence treatment, showing more than 80% control of them for 65 days. The results suggest that paraquat at 32/ha (prod.) as the foliar application followed by oxyfluorfen 0.47kg a.i./ha applied as the preemergence at one week after paraquat treatment can maintain the clean orchard more than 65 days, showing one of the promising and applicable control system in orchard.

• Applied Biological Chemistry
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• v.16 no.3
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• pp.146-165
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• 1973

Crop damages caused by sulfur dioxide poisoning were studied with respect to physiology of lesion, yield loss and prevention measures. The results are summarized as follows; 1. On the physiology of injury: The sulfur dioxide gas did no: affect the pH and $E_h$ values of the tested leaf juice of plants. Peroxidase activity was inhibited just after sulfur dioxide treatment but gradually recovered to normal after 10 hours. Methanolic chlorophyll solution was instantaneously and irreversibly bleached by the addition of sulfur dioxide gas with no evidence of pheophytin formation. It seems that chlorophyll forms colourless addition product or is reduced to colourless form with either sulfur dioxide gas or sulfurous acid. Chlorophyll in the chloroplast was also bleached by the sulfur dioxide treatment, as in the case of methanolic solution of chlorophyll, except that the rate of bleaching was rather slow, requiring 1-2 hours. It appears that the most inflicting cause of sulfur dioxide gas to plants may be the destruction of chlorophyll by the poisoning gas. 2. On the effects to crop yield: The crop yield losses were proportional to the concentration of inflicting sulfur dioxide gas. The order of tolerence of the crops to the sulfur dioxide gas was as follows - chinese cabbage being the most susceptible; wheat, paddy rice, barley, soybean, welsh onion, radish and chinese cabbage. The crucifer crops were generally found more susceptible than other crops studied. With respect to the growing stages of crops exposed to sulfur dioxide gas, it was found that the flowering stage was the most susceptible fellowed by panicle forming, milky and tillering in the decreasing order of susceptibility. 3. On the preventive measures of yield losses: Soil applications of potassium, wollastonite, lime or spray of lime water were effective to prevent yield losses from sulfur dioxide fumigation of paddy rice, barley, and soybeans. The most responsive treatment was lime water spray for all crops tested. In case of sulfur dioxide fumigated paddy rice, the lime water spray also increased carbon assimilation.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.330-339
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• 2010

In order to suggest correct direction of researches on Miscanthus spp. which are promising bioenergy crop, authors had reviewed and summarized various literature about botanical taxonomy, morphology and present condition of breeding, cultivation and utilization of miscanthus. Among the genus of Miscanthus which are known 17 species, the most important species are M. sinensis and M. sacchariflorus which origin are East Asia including Korea, and M. x giganteus which is inter-specific hybrid of tetraploid M. sacchariflorus and diploid M. sinensis. Miscanthus is superior to other energy crops in resistance to poor environments including cold, saline and damp soil, nitrogen utilization efficiency, budget of input energy and carbon which are required for producing biomass and output which are stored in biomass. The major species for production of energy and industrial products including construction material in Europe, USA and Canada is M. x giganteus which was introduced from Japan in 1930s. In present, many breeding programs are conducted to supplement demerits of present varieties and to develop "Miscanes" which is hybrid of miscanthus and sugar cane. In Korea, the researches on breeding and cultivation of miscanthus were initiated in 2007 by collecting germplasms, and developed "Goedae-Uksae 1" which is high biomass yield and "mass propagation method of miscanthus" which can improve propagation efficiency in 2009. In order to develop "Korean miscanthus industry" in future, the superior varieties available not only domestic but also foreign market should be developed by new breeding method including molecular markers. Researches on production process of cellulosic bio-ethanol including pre-treatment and saccharification of miscanthus biomass also should be strengthen.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.101-109
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• 2014

In order to save costs and enhance quality in construction without damaging the environment, the VE/LCC analysis method is increasingly used. This study was carried out to conduct a value analysis for the ecological restoration of a slope considering life cycle cost and performance. The construction conditions were classified into three types(A, B, C) according to the condition of each base. Three construction methods for slope ecological restoration were selected by each condition. Eventually, a value analysis was conducted for total nine conditions by analyzing the life cycle cost and performance. The gradient of slope and base of Condition 1 were below 1:1.2 and general soil, while condition 2 and 3 were below 1:1.0(reaping rock) and below 1:0.7(soft rock, blasted rock), respectively. A value analysis was conducted based on the value estimated via life cycle cost and performance analysis. The result showed that the B construction method had the highest value in Condition 1 as it showed 108.4, while A and C showed 90.3 and 45.8, respectively. When it comes to Condition 2, Construction Method A indicated the highest value as it showed 89.1(B: 47.5, C: 47.0). In Condition 3, Construction Method A(89.1) was the highest, while B and C showed 55.4 and 40.2, respectively. Based on the result of this study, in order to make a reasonable decision that can enhance quality and reduce costs in slope ecological restoration, the slope ecological restoration method must be reviewed in consideration of life cycle cost and performance.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.1
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• pp.23-28
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• 2015

This study was performed to investigate the adequate standard pot and number of plants per tree of raising seeding pot on the foxtail millet transplanting culture in the southern province. Due to the various application of wellbeing-health food recently, for upbringing of the foxtail millet, millet and sorghum in minor cereals, R & D and policy support is being promoted actively. The foxtail millet growing season is so short from 90 to 130 days, and it is large variations for a growth temperature. The main results are as follows. When it comes to foxtail millet transplantation, seedling quality of 406 holes, 200 holes and 162 holes of raising seeding pot type were not all significant, and field rooting percentage is accounted for all 94 to 95%. Yield of a foxtail millet was exposed in 406holes 305 kg/10a>162holes 303 kg> 200holes 302 kg order, and it was no significance between test processing. When it's the raising seeding transplanting culture, in case of pot culture, 406holes pot culture were reduced the bed soil cost 63%, pot 50%, working hours 18% for 200holes pot. Transplanting seedling quality per a foxtail millet transplanting culture method, dry weight was high inclination as transplanting number of plant is less, and field rooting percentage displayed more than all 95%. Yield appeared to 2 plants seedling transplanting 315kg/10a> 3 plants seedling transplanting 304kg>1 plant seedling transplanting 256kg order. The projected cost per the pot-sort on the raising seeding transplanting culture of foxtail millet, the seedling transplanting culture of 406holes was reduced 40% percentages compared to 200holes as 76,230won/10a. As a result, 406holes pot and 2plants seedling transplanting culture, labor-saving culture was possible.

• The Journal of Engineering Geology
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• v.24 no.4
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• pp.551-574
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• 2014

The occurrence, distribution, and hydrogeochemical characteristics of uranium and radon in groundwater within different lithologies in Gyeongnam and Gyeongbuk provinces were investigated. A total of 201 groundwater samples from sedimentary rocks taking a large portion of the geology and from igneous rocks taking a small portion of the geology were analyzed and examined using factor analysis. Their radionuclide levels were used to construct detailed concentration maps. The groundwater types, defined using a Piper diagram, are mainly Ca-$HCO_3$ with less Na-$HCO_3$. Among the samples, one site exceeds $30{\mu}g/L$ of uranium (i.e., the maximum contaminant level of the USEPA) and three sites exceed 4,000 pCi/L of radon (i.e., the alternative maximum contaminant level). No samples were found to exceed the 15 pCi/L level of gross alpha or the 5 pCi/L level of radium. The concentration of uranium ranges from 0.02 to $53.7{\mu}g/L$, with a mean of $1.56{\mu}g/L$, a median of $0.47{\mu}g/L$, and a standard deviation of $4.3{\mu}g/L$. The mean concentrations of uranium for the different geological units increase in the following order: Shindong Group, Granites, Hayang Group, Yucheon Group, and Tertiary sedimentary rocks. The concentration of radon ranges from 2 to 8,740 pCi/L, with an mean of 754 pCi/L, a median of 510 pCi/L, and a standard deviation of 907 pCi/L. The mean radon concentrations for the investigated geological units increase in the following order: Granites, Yucheon Group, Tertiary sedimentary rocks, Hayang Group and Shindong Group. According to the factor analysis for each geological unit, uranium and radon behave independently of each other with no specific correlation. However, radionuclides show close relationships with some components. Regional investigations of radionuclides throughout the country require an integrated approach that considers the main lithological units as well as administrative districts.

• Korean Journal of Organic Agriculture
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• v.20 no.4
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• pp.535-542
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• 2012

This study was carried out from 2011 to 2012 in order to analyze the cultivation technology system by six organic rice cultivation types in the southern provinces for the purpose of utilizing organic rice farming guidelines. This surveys were conducted by site visit on 8 counties and 115 farms in southern area. Cultivation technology system by six organic rice cultivation types were cultivated by the principle of minimum input or non-input. cropping systems, a mixture of barley and rice, or rice green manure crops were grown. Cultivars were mixture of the local cultivars and Japanese varieties. Soil were managed by a self-manufactured compost, indigenous microorganisms and barley straw without any fertilization. Pest control was mainly practied by purchased eco-friendly organic materials or herbal medication residue and indigenous microbial self-manufactured. Weed was controled by snails and barley straw. In addition, considering the restore of a longtail pitching shrimp and grasshoppers, the fuction of environmental ecology of six organic rice cultivation type proved to be excellent all. Meanwhile, the productivity of the organic farming per 10a were the order of Life and environment > Natural circulation > Stevia > Ji jang > Art and nature > Taepyoung of Farming Methods, but the farmers received prices showed the opposite tendency. Simple profitablity did not show a big difference. But, the productivity of all type of the organic farming were lower then the conventional farming. Finally, If we want to conduct safety and easy farming, we can suggest stevia farming, Natural circulation farming and life and environmental farming out of 6 organic rice cultivation types.

• Economic and Environmental Geology
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• v.42 no.4
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• pp.315-333
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• 2009

In this study, the hydrochemical and the isotopic characteristics of major streams in the Daejeon area were investigated during rainy and dry seasons. The stream water shows the electrical conductivity of the range of $37{\sim}527{\mu}s$/cm, and pH $6.21{\sim}9.83$. The chemical composition of stream waters can be grouped as three types: the upper streams of Ca(Mg)-$HCO_3$ type, Ca(Mg)-$SO_4(Cl)$ type of middle streams flowing through urban area, and Na(Ca)-$HCO_3$(Cl, $SO_4$) type of the down streams. Based on in-situ investigation, the high pH of stream waters flowing through urban area is likely to be caused by the inflow of a synthetic detergent discharging from the apartment complex. The electrical conductivity of stream waters at a dry season is higher than those of at a rainy season. We suggest that the hydro-chemical composition of stream waters in the Daejeon area was affected by the discharging water from the sewage treatment facilities and anthropogenic contaminants as well as the interaction with soil and rocks. ${\delta}D$ and ${\delta}^{18}O$ values of the stream waters show the relationship of ${\delta}D=6.45{\delta}^{18}O-7.4$, which is plotted at a lower area than global meteoric water line(GMWL) of Craig(1961). It is likely that this isotopic range results from the evaporation effect of stram waters and the change of an air mass. The isotope value shows an increasing trend from upper stream to lower stream, that reflects the isotopic altitude effect. The relationship between ${\delta}^{13}C$ and $EpCO_2$ indicates that the carbon as bicarbonate in stream water is mainly originated from $CO_2$ in the air and organic materials. The increasing trend of ${\delta}^{13}C$ value from upper stream waters to lower stream waters can be attributed to the following reasons: (1) an increasing dissolution of $CO_2$ gas from a contaminated air in downtown area of the Daejeon, and (2) the increment of an inorganic carbon of groundwater inflowed into stream by base flow. Based on the relationship between ${\delta}^{34}S$ and $SO_4$ of stream waters, the stream waters can be divided into four groups. $SO_4$ content increases as a following order: upper and middle Gab stream${\delta}^{34}S$ value decreases as above order. ${\delta}^{34}S$ value indicates that sulfur of stream waters is mainly originated from atmosphere, and is additionally supplied by pyrite source according to the increase of sulfate content. The sulfur isotope analysis of a synthetic detergent and sewage water as a potential source of the sulfur in stream waters is furtherly needed.