• Journal of Bio-Environment Control
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• v.31 no.1
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• pp.67-76
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• 2022

This study aimed to determine the photosynthesis and growth characteristics of Peucedanum japonicum T. grown under aquaponics in a plant factory (AP) by comparing those grown under hydroponic cultivation system (HP). The AP system raised 30 fishes at a density of 10.6 kg·m^-3 in a 367.5 L tank, and at HP, nutrient solution was controlled with EC 1.3 dS·m^-1 and pH 6.5. The pH level ranged from 4.0 to 7.1 for the AP system and 4.0 to 7.4 for the HP system. The pH level in the AP began to decrease with an increase in nitrate nitrogen (NO₃-N) and lasted bellower than pH 5.5 for 15-67 DAT. It was found that ammonium nitrogen (NH₄-N) continued to increase even under low pH conditions. EC was maintained at 1.3 to 1.5 dS·m^-1 in both systems. The concentration of major mineral elements in the fish tank was higher than that of the hydroponics, except for K and Mg. There was no significant difference in the photosynthesis characteristics, but the PIABS parameters were 30.4% lower in the AP compared to the HP at the 34DAT and 12.0% lower at the 74DAT. There was no significant difference in the growth characteristics, but the petiole length was 56% longer in the leaf grown under the AP system. While there was no significant difference in the fresh and dry weights of leaf and root, the leaf area ratio was 36.43% higher in the AP system. All the integrated results suggest that aquaponics is a highly-sustainable farming to safely produce food by recycling agricultural by-products, and to produce Peucedanum japonicum as much as hydroponics under a proper fish density and pH level.

• Korean Journal of Agricultural Science
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• v.11 no.1
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• pp.77-84
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• 1984

This experiment was carried out to determine the effects of night temperature and amount of fertilization on growth and photosynthesis of red pepper plants for providing some basic imformation needed in improving the productivity of red pepper. 1. Plant height, stem length, number of flower buds, dry weight of plants and photosynthetic rate were higher in King Gun Gochu than in Dohusa, but number of leaves, number of internodes and leaf area we re higher in Dohusa compared to King Gun Gochu. 2. Plant height, number of leaves, number of flower buds, dry weight of plants, leaf area and photosynthetic rate were significantly increased by 50% increased fertilization compared to normal fertilization. 3. High night temperature($25^{\circ}C$) treatment increased plant height, stem length, number of leaves, number of internodes, number of flower buds, dry weight of plants and leaf area. 4. RGR and LAR were increased by 50% increased fertilization and high night temperature but NAR was decreased by high flower buds 5. Photosynthetic rate of King Gun Gochu was increased by 50% increased fertilization and high light intensity. 6. Number of flower buds was increased at King Gun Gochu by 50% increased fertilization and high night temperature ($25^{\circ}C$).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.334-339
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• 1985

A sweet corn hybrid, Honey Bantam, was planted on 24 May, 1984 in a silty clay loam soil to investigate the effects of polyethylene(P.E.) mulch and different levels and placements of Nitrogen(N) on soil properties and sweet corn growth. A split-split plot design with three replications was employed; P.E. mulch and bare soil were main plot, N levele of 8, 12, 16, and 20 kg/10a were subplot, and band and broadcast of fertilizers were sub-subplots. At early growth stage soil temperature under P.E. mulch was higher than that in bare soil by 5-10$^{\circ}C$, but the differences decreased as plant growth advanced. Soil hardness increased with soil depth while P.E. mulch reduced soil hardness probably by holding high soil moisture. Soil pH decreased up to the 6th week after planting and then increased in bare soil, but it contineously decreased up to the 8th weeks under P.E. mulch regardless N levels and placements. Electrical conductivity(EC) of soil increased up to the 6th weeks after planting and then decreased in all treatments except broadcast of fertilizers under P.E. mulch where EC increased contineously. Generally, soil EC under P.E. mulch was higher than that in broadcast. Broadcast of fertilizers did not affect emergence of seedlings in all N levels under P.E. mulch and bare soil, but band of fertilizers at all N levels under P.E. mulch and higher levels of N in bare soil reduced emergence rate significantly. Percent stand was possitively correlated with soil EC and it strongly influenced the number of marketable ears. Plant growth was enhanced and silking date was earlier by 14-19 days under P.E. mulch compared to bare soil probably due to increased soil moisture, reduced soil hardness and higher soil temperature.

• Korean Journal of Ecology and Environment
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• v.34 no.1 s.93
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• pp.62-69
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• 2001

This study was investigated discharge and water quality for rainy days at the inflow streams (Gog-Kyo, Mu-Han, Sap-Kyo and Nam-Won) into Lake Sap-Kyo from June to November of 1999. The eventual aim of this study was to improve the water quality of Lake Sap-Kyo. Therefore, in order to reduce inflow pollutants loading into Lake Sap-Kyo, we investigated characteristics of stormwater runoff and estimated pollutant loading for the rainy season. The results of that Sap-Kyo stream is $5.75\;m^3/sec$ flow and influences water quantity of Lake Sap-Kyo greatly during the dry weather. Gog-Kyo stream influence to quantity of Lake Sap-Kyo greatly for the rainy days. Gog-Kyo stream and Sap-Kyo stream are $12.13\;m^3/sec$ and $8.49\;m^3/sec$, respectively. The reason is that the watershed area of Gog-Kyo stream is larger than other streams. When we prepare to plan management to improve the water quality of Lake Sap-Kyo, we have to consider that runoff characteristics by land use. Among the annual total pollutants loading inflow Lake Sap-Kyo, the ratio of non-point pollutants loading estimated that SS, BOD, T-N and T-P are 62%, 43%, 41% and 27%, respectively. Therefore, in order to improve water quality of Lake Sap-Kyo, we have to reduce non-point pollutants loading.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.442-446
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• 2003

The Gene action for eight quantitative characters related to the plant type was estimated using diallel cross among three different plant types of sesame (Sesamum indicum L.) in 2001. The parental varieties used for diallel cross were Ahnnam and Yangbaeck as indeterminate type, ksan22 as semi-determinate type, and dt-45 and Suwon131 as determinate type. In variance and covariance analysis (Wr-Vr) for eight characters the mean square of array except for capsule length, 1,000 seed weight were significant, which suggest that varieties involved in diallel set cross may have epitasis. Complete dominance was observed in the flowering periods, and ratio of matured grains while partial dominance was observed in the plant height, no. of capsules per plant, and no. of branch per plant. Broad sense heritability for flowering periods, plant height, no. of capsules per plant, and no. of branch per plant ranged from 0.91 to 0.99. Narrow sense heritability for flowering periods, capsule length, ratio of matured grain, 1,000 seed eight were 0.18 to 0.34, and plant height, no. of capsules per plant and no. of branch per plant were ranged 0.77 to 0.81.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.6
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• pp.516-521
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• 2004

The straw of thirty one rice varieties were evaluated for their feed value and related agronomic traits. The rice straw were hand-harvested, dried to constant weight at $75^{\circ}C$ and ground through a 20 mesh seive in a Wiley mill, analyzed with crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF). Relative feed value (RFV) was calculated from NDF and ADF. The sum of standardized score was estimated by dry weight of rice straw, content of CP, ADF and NDF. The straw yield of Daeanbyeo was 725.9 kg/10a, showed heighest value among the varieties and remainder was in the order of Keumnambyeo, Donginbyeo #1 and Chucheongbyeo. Crude protein (CP) content in a Dasanbyeo was higher than those in other varieties. The content of ADF in a Junghwabyeo and NDF in a Sobaegbyeo were $34.3\%$ and $63.8\%$, respectively, showed lowest value among the varieties. The rice straw of Dunnaebyeo, Obongbyeo, Seoanbyeo, Keumobyeo, Hwaseongbyeo, Noganbyeo and Gyehwabyeo belonged to the high feed value varieties by estimation of cluster analysis, sum of standardized score and RFV. The content of CP was found to be positively related with dry weight of leaf and grain, but negatively related with heading days after seeding, culm length, specific leaf weight (SLW) and dry weight of stem. ADF and NDF were found to be positively related with heading days after seeding, culm length, SLW and dry weight of leaf, but negatively related with dry weight of stem. The sum of standardized score and RFV were the only positive relationship with dry weight of stem and negative relationship with other traits.

• Tunnel and Underground Space
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• v.18 no.1
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• pp.44-57
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• 2008

In this study, a 2D finite-element analysis, using the SEEP/W program, was carried out to estimate the amount of groundwater flawing into a tunnel, as well as the groundwater tables around wetland areas during and after a tunnel excavation through rock mass. Four sites along the Wonhyo-tunnel in Cheonseong Mountain (Gyeongnam, Korea) were analysed, where the model damain of the tunnel included both wetland and fault zone. The anisotropy of the hydraulic conductivities of the rock mass was calculated using the DFN model, and then used as an input parameter for the cantinuum model. Parametric study on the influencing factors was perofrmed to minimize uncertainties in the hydraulic properties. Moreover, the volumetric water content and hydraulic conductivity functions were applied ta the model to reflect the ability of a medium ta store and transport water under both saturated and unsaturated conditions. The conductivity of fault zone was assumed ta be $10^{-5}m/sec\;or\;10^{-6}m/sec$ and the conductivity of grouting zone was assumed as 1/10, 1/50 or 1/100 of the conductivity of rock mass. Totally $6{\sim}8$ cases of transient flow simulation were peformed at each site. The hydraulic conductivities of fault zone showed a significant influence on groundwater inflow when the fault zone crossed the tunnel. Also, groundwater table around wetland maintained in case that the hydraulic conductivity of grouting zone was reduced ta be less than 1/50 of the hydraulic conductivity of rock mass.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.132-137
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• 2008

This experiment was conducted to investigate the effect of supplemental lighting of low light intensities on growth and yield of rose 'Vital' in a forcing culture. Metal halide lamp (MH), High pressure sodium lamp (HSP), and MH+HSP were used as the light sources, and they were set up at a $310\;cm{\times}450\;cm$ interval and at 120cm above the culture beds. Light intensity at 1m point distance from supplemental lighting sources was $32{\sim}34\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Days to the 1st and 2nd harvests decreased by $5{\sim}8$ and $3{\sim}5$days, respectively in supplemental lighting treatment as compared to the control. Days to harvesting was the shortest in MH+HPS treatment, followed by BPS and MH, although there was no significant difference between HPS and MH treatments. The growth was better and incidence of blind shooting decreased by $5{\sim}7%$ in supplemental lighting treatments than the control, increasing marketable cut flowers. The incidence of blind shoot was the lowest in MH+BPS treatment, and there were no significant difference between MH and BPS treatments. In conclusion, supplemental lighting of low light intensities was effective in reducing days to flowering and reduced occurrence of blind shoots.

• Journal of Bio-Environment Control
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• v.14 no.3
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• pp.160-165
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• 2005

Since the growth and quality of oak mushrooms are sensitively affected by environmental conditions, an adequate environmental control is very essential to improve the yield and quality under protected cultivation. In this study, the diameter, thickness, length and hardness of cap and stipe, the dry weight, fresh weight and moisture content of the mushrooms were analyzed under the environmental conditions such as night air temperatures (control, $5{\~}11^{\circ}C$ and $12{\~}18^{\circ}C$), relative humidities in the daytime (control, humidifying for 6 h and 12 h), and wind velocities (control, fan-operation for 6 h and 12 h). At a lower night temperature, the quality of the mushrooms was improved, and considered to be optimum at $3{\~}8^{\circ}C$ in terms of fresh weight and quality. At $70{\~}80{\%}$ of relative humidity in the daytime, the fresh weight was increased, but the quality decreased. Considering the quality, the relative humidity in the daytime is adequate at around $50{\%}$. At 6 h of maintaining the wind velocity at $1{\~}2\;my{\cdot}s^{-1}$, the growth and quality were better, but the lightness became higher at 12 h although the fresh weight was reduced by evaporation. It is concluded that even though both of the yield and quality are not easily improved at a same time, optimum approaches should be required by using the relationship among environmental factors and the growth and quality.

• Korean Journal of Organic Agriculture
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• v.20 no.2
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• pp.231-241
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• 2012

Farming using natural salts for supply of nutrients to crops is increasing recently. It is necessary to evaluate the salt accumulation in soil and the effects on crop growth by treatment of natural salt. This study was conducted at the organic cultivation fields which garlics were planted. The treatments were no natural salts (control) and plots applied 100~600 $kg\;ha^{-1}$ with natural salts. Soil samples were taken from the 0 to 25 cm depth at 12 and 107 day (harvest time) after natural salts application. The results showed that electrical conductivity (EC), exchangeable Na (Exch.$-Na^+$) and Cl- were increased by application of natural salts. But, pH and exchangeable cations ($K^+$, $Ca^{2+}$ and $Mg^{2+}$) had not significantly differences among treatments. In 300 $kg\;ha^{-1}$ plots of natural salt, the level of EC, Exch.$-Na^+$ and $Cl^-$ in top soil (0-5 cm) was were increased more 0.3, 3.7, and 12.7 times than control plot, respectively. EC, Exch.$-Na^+$, and $Cl^-$ were highest in the top 5 cm of soil and decreased with depth at 12 days after natural salts application, but were decreased in the plower layer (0-15cm) at the harvest time because they were leached with natural rain. An increasing the application level of natural salt resulted in increasing of sodium adsorption ratio, exchangeable sodium percentage, and percentage of soil dispersion. The concentration of nutrient uptake such as total nitrogen (T-N), chloride (Cl) in garlic had significant difference between control and plots applied with natural salts The content of T-N of garlic in plots with natural salt application was lower than control plot, but Cl is higher than control plot.