• Korean Journal of Soil Science and Fertilizer
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• v.27 no.1
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• pp.15-20
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• 1994

Lysimeter experiments were conducted to elucidate the behavior of $NO_3-N$ derived from urea applied at different rates and accompanying cations in soils and to further provide fundamental information of rational nitrogen-fertilizer management. Urea was applied at rates of 0, 7, 14, 21, 28 and 35kg N/10a to sandy loam pakced into PVC cylindrical lysimeter(vol. : $0.187m^2$, area $0.43m^2$). Leachates from the lysimeter with or without grass grown were collected periodically and analyzed for $NO_3$ and cations. Grass growth and yield responses to N fertilization were also examined. Dry matter yield and nitrogen uptake increased with the urea application rate. The amount of leachate from the lysimeter was negatively correlated with urea application ratesl($r=-0.95^{**}$). The nitrate leaching loss with grass grown was 230 g N/10a at the maximum rate of 35kg N/10a, but the highest leaching loss was observed as 1,607 g N/10a from the bare plot. Increase in urea application rates decreased significantly leaching losses of Ca, Mg, K and Na(>0.01). The highest leaching loss from the bare plot was observed for Ca but only 6.5% of exchangeable form and 14.0% for K from the grass plot respectively. Equivalent ratio of cations to nitrate leached were 3.2 % for the bare plot and the ratio for the grass plot increased with the urea application rate, ranging from 18.6 to 32.7%.

• Current Research on Agriculture and Life Sciences
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• v.26
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• pp.55-62
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• 2008

To obtain food materials of high isoflavone content from soy-sprouts, 8 soy-sprout varieties, Aga 1, Aga 2, Aga 3, Aga 4, Pungsannamulkong, Eunhakong, Jangkikong and Bosugkong, were grown into soy-sprouts for 7 days under light condition and stored for 5 days at 6 different temperatures; 3, 6, 9, 20, 30, and $40^{\circ}C$ in the dark. The isoflavone content of 7 days grown sprout varieties were highest in the order of Aga 3>Aga 1>Aga 2>Aga 4>Jangkikong>Bosugkong>Eunhakong>Pungsannamulkong. The highest isoflavone content of Aga 3 was $4,619{\mu}g/g$. The isoflavone content of soy-sprouts showed much varietal differences depending on the storage temperatures. Comparative high isoflavone content was obtained at storage temperatures of $6^{\circ}C$ and $20^{\circ}C$ while most of varieties showed low isoflavone content at $9^{\circ}C$ and $30^{\circ}C$. No constant trend in isoflavone content for the tested varieties along with the days to storage but most of varieties showed the highest isoflavone content in 3 days of storage. On the contrary, Aga 4 and Jangkikong showed high isoflavone content even at 5 days of storage. The comparatively high isoflavone content for 4 varieties including of Aga 3 out of 8 varieties was obtained from the treatment of one day storage at $20^{\circ}C$. Out of all treatments, the highest isoflavone content was obtained from one day storage at $20^{\circ}C$ for Aga 3 and the content was as high as $11,705{\mu}g/g$. In this experiment, soy-sprouts were believed to be made continuous growth during the storage because the sprouts were being dipped in water during the temperature treatment to protect soy-sprouts from drying. Thus, it is inferred that additional researches should be made to establish better method to increase isoflavone content in soy-sprouts during the storage.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.26-32
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• 2004

Growth and yield of cucumber (Cucumis sativus L.) with arch training method were evaluated on several training heights, planting densities, and topping node orders. Cucumber cultivar 'Eunsung-baekdadagi' was planted on 9 June with three training heights of 1.5, 1.8, and 2.1 m, there planting densities of 90${\times}$40, 90${\times}$50, and 90${\times}$60 cm, and five topping node orders of 20th, 30th, 35th, and nontopping. The plot of 2.1 m training height resulted in the higher sun-scald fruit rates due to the higher temperature above 37$^{\circ}C$ in the upper space of plastic house. The plot of 1.8 m arch training height showed higher fruit setting and marketable yield rate compared to the other training heights. The maketable yield rate with 1.8 m height arch training was 102,691 kg ${\cdot}$ $ha^{-1}$, 21% higher value than that of 1.5 m. Powdery mildew incidence increased with the increase of planting density. Lower LAI were shown depending on the higher topping node order. Lower light transmission ratio was shown in the higher planting density plots, might be due to the crowded stems and leaves inside those plots. Fruit setting rate was also higher in main stems rather than in lateral ones. Marketable yie이 in 90${\times}$50 cm planting distance with 35th node topping treatment was 98,311 kg ${\cdot}$ $ha^{-1}$, 5% higher than that 90${\times}$40 cm planting distance with 30th node topping treatment. Thus the 1.8 m of training height, 90${\times}$50 cm of planting distance, and 35th node topping was evaluated for the effective cultivation condition in arch training of cucumber in highland.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.470-475
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• 1999

This study was conducted to evaluate the utilization of animal by-product mixture (ABPM) as a dietary animal protein source of fish meal replacer, and to determine the effect of dietary chromic oxide in growing rainbow trout, Oncorhynchus mykiss. ABPM is a mixture of five anmial by-products such as meat and bone meal (MBM) feather meal (FM), squid live, powder(SLP), poultry by-product (PBP) and blood- meal (BM) at a specific weight based ratio. Diet 1 and 2 were formulated on a isonitrogenous and a isocaloric basis of $46.5\%$ crude protein and 16.7 KJ/g diet; diet 1 (WFM 100), $100\%$ of the animal protein source came from white fish meal; diet 2 (ABPM 40), $60\%$ WFM+$40\%$ ABPM as the animal protein source; diet 3 (-Cr) commercial diet without chromic oxide; diet 4 (+Cr), commercial diet with chromic oxide. After eight weeks of feeding trials, fish fed diet 2 had a significantly lower body weight gain (WG) and feed efficiency (FE) than that of fish fed the other diets (P<0.05). When comparing diet 3 with diet 4, no significant differences were found in WG and FE (P>0.05). There were no significant differences on condition factor, hematocrit level, serum phosphorus, bone phosphorus, whole body phosphorus, and bone ash among fish from all four diet groups. Fish fed diet 4 had a significantly higher whole body lipid than that of fish fed the other diets (P<0.05), These results indicated that ABPM could be used less than $40\%$ in growing rainbow trout with a sufficient period of acclimation, In addition, the $0.5\%$ of chromic oxide can be used to determine the apparent digestibility of the nutrients in the feed without any adverse effects on growth and body composition.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.324-327
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• 2008

'Onnuri' is a japonica rice cultivar developed from the cross between 'Milyang 165' and HR14732-B-67-2-3 at Honam Agricultural Research Institute (HARI), NICS, RDA, in 2005. This cultivar has a short grain shape and about 121 days growth duration from transplanting to harvesting in Korean climate condition. In reaction to biotic and abiotic stresses, it shows resistance to blast, bacterial blight pathogen from $K_1$ to $K_3$ and stripe virus, but susceptible to other major diseases and insect pests. The milled kernel of 'Onnuri' is translucent with non-glutinous endosperm. It has about 18.6% of amylose content and better palatability of cooked rice compared with 'Chucheongbyeo' cultivated in Kyunggi province. The milled rice yield of 'Onnuri' is about 5.94 MT/ha under the standard fertilizer level of the ordinary transplanting cultivation. 'Onnuri' would be adaptable to southern plain of Cheonan, middle-northern plain, and southern mid-mountainous of Korea.

• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.605-619
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• 2019

The objective of this study was to analyze eutrophication characteristics, empirical model analysis, and variation of water quality according to monsoon intensity in Hapcheon Reservoir for 16 years from 2002 to 2017. Long-term annual water quality analysis showed that Hapcheon Reservoir was in a meso-nutrition to eutrophic condition, and the eutrophic state intensified after the summer monsoon. Annual rainfall volume (high vs. low rainfall) and the seasonal intensity in each year were the key factors that regulate the long-term water quality variation provided that there is no significant change of the point- and non-point source in the watershed. Dry years and wet years showed significant differences in the concentrations of TP, TN, BOD, and conductivity, indicating that precipitation had the most direct influence on nutrients and organic matter dynamics. Nutrient indicators (TP, TN), organic pollution indicators (BOD, COD), total suspended solids, and chlorophyll-a (Chl-a), which was an estimator of primary productivity, had significant positive relations (p<0.05) with precipitation. The Chl-a concentration, which is an indicator of green algae, was highly correlated with TP, TN, and BOD, which differed from other lakes that showed the lower Chl-a concentration when nutrients increased excessively. Empirical model analysis of log-transformed TN, TP, and Chl-a indicated that the Chl-a concentration was linearly regulated by phosphorus concentration, but not by nitrogen concentration. Spatial regression analysis of the riverine, transition, and lacustrine zones of $log_{10}TN$, $log_{10}TP$, and $log_{10}CHL$ showed that TN and Chl-a had significant relations (p<0.005) while TN and Chl-a had p > 0.05, indicating that phosphorus had a key role in the algal growth. Moreover, the higher correlation of both $log_{10}TP$ and $log_{10}TN$ to $log_{10}CHL$ in the riverine zone than the lacustrine zone indicated that there was little impact of inorganic suspended solids on the light limitation in the riverine zone.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.191-205
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• 1995

The carrier materials used for the development of bacterial inoculants to be effective in field were made with various carrier materials of two major forms, alginate bead and powder inoculants. Inoculants were prepared after mixing those carrier materials with Pseudomonas fluorescens SSL3 and Bacillus subtilis B5, and the treatment effects of each inoculants was investigated on cucumber, tomato, pepper and potato. Survival density of SSL3 and B5 in various carrier materials for duration of storage and the bead inoculants were better than the powder. In the powders, survival rate increased in carrier materials treated 5% skimilk. The growth condition of microorganisms in carrier materials is good at powder. When they were preserved in the long period, contamination is problem. Scanning(200 to 600nm) of the P. fluorescens SSL3 supernatant in centrifuged MKB broth incubated for 48h had two main peaks, pyochelin(300nm) and pyoverdin(400nm). The potato yield in field experiments of spring, treated with bead formulas showed increase of 22~29% in whole potato breeds as compared with control, because the bead formulas degraded, and released the antibiotic microorganisms in slow and constant rate. In the pot experiment, there were significant difference in soil, wheatbran, and bead formed wheatbran.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1559-1572
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• 2021

The response of vegetation under the crop stress condition was evaluated using structural, biochemical, and physiological vegetation indices based on unmanned aerial vehicle (UAV) images and field-spectrometer data. A high concentration of herbicide was sprayed at the different growth stages of garlic to process crop stress, the above ground dry matter of garlic at experimental area (EA) decreased about 46.2~84.5% compared to that at control area. The structural vegetation indices clearly responded to these crop damages. Spectral reflectance at near-infrared wavelength consistently decreased at EA. Most biochemical vegetation indices reflected the crop stress conditions, but the meaning of physiological vegetation indices is not clear due to the effect of vinyl mulching. The difference of the decreasing ratio of vegetation indices after the herbicide spray was 2.3% averagely in the case of structural vegetation indices and 1.3~4.1% in the case of normalization-based vegetation indices. These results meant that appropriate vegetation indices should be utilized depending on the types of crop stress and the cultivation environment and the normalization-based vegetation indices measured from the different spatial scale has the minimized difference.

• Korean Journal of Organic Agriculture
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• v.29 no.2
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• pp.223-240
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• 2021

This study was carried out to investigate the economic value of organic wheat production using gelatin·chitin microorganisms in Gwangsan-gu, Gwangju city. The soil condition of experiment field was clay loam Jisan series. The organically cultivated fields were sprayed gelatin and chitin degrading bacteria. The test was performed at conventionally cultivated field and organically cultivated field. Emergence of weed on organically cultivated field was significantly higher than conventionally cultivated field which sprayed herbicide before seeding. Weed emergence have a critical impact on grain yield. Occurrence of diseases and insect pests were higher than conventionally cultivated fields. In 2019, the amount of lodging in conventionally cultivated field were higher than conventionally cultivated field. In 2020, lodging and wet injury were occur in both field. Comparing yield element between organically and conventionally cultivated experimental area, grain yield in organically cultivated field was shown slightly higher amount than conventionally cultivated field. However in the actual yield of 2019, organically cultivated field shows 20% deceased yield because of overgrown weed. In 2020, weed emergence and yellow mosaic virus by wet injury cause 30% decease in the grain yield in organically cultivated field. Content of protein, carbohydrates, ash, water and fat in the grain were not different significance. In 2019, net incomes of conventionally cultivated wheat was 461,031 won/0.1 ha while organically cultivated wheat was 443,437 won/0.1 ha. In the rate of income, conventionally cultivated field was 83.0% as against organically cultivated field (73.3%). In 2020, net incomes of organically cultivated wheat was 437,812 won/0.1 ha while conventionally cultivated wheat was 418,281 won/0.1 ha. In the rate of income, conventionally cultivated field was 81.6% as against organically cultivated field (73.0%).

• Journal of Climate Change Research
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• v.5 no.1
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• pp.1-12
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• 2014

With continued economic growth, Korea has seen an increase in the nighttime activities of its citizens as hours of activity have extended into night. There is an increasing trend in energy consumption related to citizens' nighttime activities. In order to analyze ideas for an efficient replacement of the power consumption of streetlights and for profit generation by applying grid-type solar systems, this study used an RETScreen model. Through energy analysis and cost analysis, the application benefit and viability of grid-type solar street light systems were analyzed. With analysis result of a total weekly power generation of 114 kWh via a grid-connected solar streetlight system, it was shown that the net present value of a grid-connected solar street light system is 155,362 KRW, which would mean a payback period of about 5.2 years, and as such, it was shown that profit could be generated after about 6 years. In addition, if the grid-connected solar power generation system proposed by this study is to be applied, it was shown that 401,935 KRW in profit could be generated after the 20-year useful life set for the solar system. In addition, the sensitivity analysis was performed taking into account the price fluctuations of SMP, maintenance. As a result, a payback period has increased by 1~2 years, and there were no significant differences. Because the most important factor that affect the economic analysis is the cost of supply certification of renewable energy, a stable sales and acquisition of this certification are very important. the Seoul-type Feed in Tariff(FIT) connected to other institutions will enable steady sales by confirming to purchase the certification for 12 years. Therefore, if those issues mentioned above are properly reflected, Central-grid PV system project will be able to perform well in the face of unfavorable condition of solar PV installation.