• Journal of Practical Agriculture & Fisheries Research
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• v.19 no.1
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• pp.5-14
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• 2017

This study was conducted to investigate the effects of nutrient solution strength on growth and nutrient element concentrations in leaf lettuce (Lactuca sativa L. cv. 'Dduksum') by hydroponic culture under fluorescent lamp and LED. Leaf lettuce were grown in closed hydroponic cultivation systems supplied with 1/2, 1 and 2 strength of nutrient solution recommended by horticultural experiment station in Japan. The growth of 'Dduksum' was highest in the 2 strength of standard nutrient solution. The amount of nutrient element in the recycled nutrient solution was higher at 2, 1 and 1/2 strength of nutrient solution. The concentration of NO₃-N, Ca²⁺, Mg²⁺ in the recycled nutrient solutions increased in 1 and 2 strength of nutrient solution but that of NH₄-N decreased gradually in 1/2 and 1 strength of nutrient solution. The concentration of K, Ca, Mg in leaf lettuce was maintained in the normal range, whereas the concentration of phosphorous was 1.3 to 1.6%, which was higher than proper range. As the concentration of NH₄-N decreases gradually in all the treatments, it is necessary to raise the rate of NH₄-N or add it.

• Journal of Practical Agriculture & Fisheries Research
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• v.18 no.1
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• pp.71-78
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• 2016

The present study was performed to examine the high temperature adaptability with CO₂ treatment for tomato under the condition of greenhouse cultivation during summer season. The plants with the CO₂ concentration of 1000 ppm recorded higher scores in Fm/Fo and Fv/Fm but lower score in Fo than others through the measurement of chlorophyll fluorescence, which implicated that the plants with the CO₂ concentration of 1000 ppm had more adaptability to high temperature than the others. At the condition of the same air temperature as 30℃ and 40℃, the photosynthetic rate was increased with the increase of CO₂ concentration. When in the high air temperature state of 40℃, although the photosynthic rate was low in comparison with 30℃, its value was about 18.5umolm^-2s^-1 in case of 1000ppm. The higher concentration of CO₂ made the more activated anti-oxidation enzyme (superoxide dismutase and peroxidase) for the both cultivars as 'momotaro' and 'minichal'. The cultivar of 'minichal' performed the high temperature limit as 41℃ at the CO₂ condition of 500 ppm and 43℃ at the CO₂ condition of 1000 ppm through the estimation on the variation of chlorophyll fluorescence Fo by CO₂ concentrations.

• Journal of Practical Agriculture & Fisheries Research
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• v.19 no.1
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• pp.39-49
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• 2017

The present study conducted a comparison on tree growth and productivity of high-density apple orchards by several orchard management systems: making scaffolds by heading-back and thinning out pruning (T-1), maintaining scaffolds upward and bearing shoots downward (T-2), managing branches slightly upward without heading-back (T-3), keeping leaders downward and shoots pending (T-4), maintaining leaders high and branches horizontal with severe pinching (T-5), making leaders with lower branches vigorous and upper shoots pending (T-6), and controlling very high planting density with bending branches (T-7). In conclusion, the orchards of (T-5) and (T-6) management systems showed a superior performance in controlling tree growth, productivity, and quality of fruits. Also, superior management efficiency was obtained in the orchards of (T-5) and (T-6).

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.2
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• pp.35-47
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• 2019

The mycelial growth of P. coccineus strain was good in PDA and YMA, but mycelial growth was low in MEA. Light irradiation during the incubation period affected the pigment formation and density of mycelia. Mushroom of P. coccineus strain was able to produce fruiting bodies in both bottle and bag cultivation, and oak sawdust was found to be the most suitable substrate for spawn culture and cultivation. In artificial cultivation using sawdust medium, fruiting body was grown to the extent that visual observation was possible from the 15th day, and it formed about 5 days fast in the treatment group with low relative humidity. From 40 to 45 days of mushroom development, mature fruiting bodies could be harvested, and the lower relative humidity of the growing room favored mushroom development and growth. Antioxidant activity of fruiting bodies harvested from artificial cultivation showed that ABTS radical scavenging activity of bottle-cultivated and wild fruit bodies were shown at 505㎍/㎖ and 515㎍/㎖, respectively. However, fruiting bodies harvested in bag cultivation were high at 910㎍/㎖. As a result of DPPH radical scavenging activity, all extracts were found to be inactive, exhibiting IC₅₀ value of more than 2,000㎍/㎖ concentration. The ethyl acetate extract of mushrooms obtained from bottle cultivation showed the highest activity with 1,550㎍/㎖ IC₅₀ value. Methanol extract of wild fruit bodies had the highest ABTS radical scavenging activity at the same concentration (10mg/㎖).

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.2
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• pp.105-114
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• 2018

The aim of this study was to evaluate the change of phenolic compounds after phosphite treatment on Cheorwon onion. Onion is a perennial plant belonging to the lily family. It is native to Persia of Southwest Asia. It is widely cultivated in the temperate regions of the world. Onion is a good name for the 'Okchong' to drop blood cholesterol and cardiovascular blood flow to increase the prevention of adult diseases. Cheorwon area is inland, but it has high continental climate due to its high altitude. Therefore it is said that the onion cultivated in this region has higher sugar content and higher taste than onion grown in the southern region. Phosphorus components are particularly important ingredients for promoting muscle development. However, if the phosphoric acid content of the soil part is maintained to a large extent until the harvest, the competition of the nutrients tends to cause decay of the root part. Therefore, it is important to improve the quality and shelf life of onion by inducing nutrient balance by applying foliar fertilization method on the reducing phosphorus at harvest time. In this study, acidity was controlled by diluting phosphorous acid(H₃PO₃) and potassium hydroxide(KOH), followed by leaf surface treatment with phosphite on onion. In this study, the concentration of phosphite was diluted to 500, 1,000, 1,500ppm and sprayed three times over the onion leaves in May 2018 using an atomizer and harvested at the end of June, and the phenolic compounds were analyzed by HPLC. As a result, the content of quercetin, one of the important substances in onion, was phosphite 500ppm(179.70㎍/g), 1,000(150.27), 1,500(105.95). The contents of caffeic acid, p-coumaric acid, ferulic acid, rutin, kaempferol, and sugar content were higher in the treatments than in the control. Therefore, the phosphite does not have a great influence on the growth, but it may play a role as a method of achieving balance with nitrogen in the rainy season by supplying the role of the material catalyst and the water soluble phosphoric acid and the potassium in the influence of the material change.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.1
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• pp.81-87
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• 2019

The investigation of mycelial growth for artificial cultivation in T. albuminosus determined that within PDA, YM, MEA medium, both KNCAF 9001 and 9002 strains showed the highest mycelial growth in MEA media with 89, 81 mm, respectively, followed by YM, PDA in respected order. Furthermore, optimal mycelial growth of 89 and 77 mm in 9001 and 9002, respectively, at 25 ℃. Mycelial growth rapidly decreased at 30 ℃, but it was confirmed that it survived at 40 ℃. At pH 6, mycelial growth was fast with growth of 89 and 88 mm for both 9001 and 9002, respectively. In the case of 9001, the addition of with cotton seed hull(80%) and rice bran (20%) each other resulted in maximum productivity of 99 mm/10 days. The result differed in order of corn cob(97 mm), oak sawdust(96 mm) and poplar sawdust(93 mm). Ultimately, the result confirmed that addition of rice bran in comparison to bran resulted in higher yield. Even with identical medium component, 9002 showed the same tendency as 9001 but its growth was relatively slower than 9001. The effect of mycelial growth on the moisture content of the medium was best at 101. 94 mm/10 days when the moisture content of 9001 and 9002 was 65%. Mycelial growth rate tended to be slower when the moisture content was higher or lower than 65%.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.1
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• pp.75-87
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• 2018

This study was carried out to investigate the effects of planting time on the survival rate and growth. Ilex cornuta Lindl., I. aquifolium 'Silver Queen', Ardisia pusilla 'Variegata', and Rhododendron indicum(Satsuki azalea) were planted in pottery pot six times such as April 1, June 1, July 1, August 1, October 1, and December 1 in 2017. The survival rate of I. cornuta Lindl. planted in April, October, and December was 100%, whereas the survival rates were 90% in June, 50% in July, and 60% in August, respectively. The survival rates of I. aquifolium 'Silver Queen' and R. schlippenbachii were also shown about 60% in July and 70% in August, which were lower than in the other planting times at 100%. However, the survival rate of A. pusilla 'Variegata' was shown 100% in the all planting times. The growth rates of plant length, plant height or leaf length or any others of I. cornuta Lindl. were shown 20.0%, 15.5% and 16.5% planted in June, July, and August, respectively, while those planted in April, October and December were 3.2%, 12.3% and 10.7% respectively. Similarly, the growth rates of leaf numbers and plant length of I. cornuta Lindl., A. pusilla 'Variegata', and R. indicum(Satsuki azalea) planted in summer season from June to August for all plat (not only leaf numbers and plant length in was facilitated, while the growth was restrained in planting for spring or autumn. Therefore, the plantation during summer is better for increasing the survival rate and promoting the growth.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.2
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• pp.15-25
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• 2019

The effect of blueberries on the quality characteristics of strawberry jam substituted with 50% sugar, glucose syrup 10% was investigated. Strawberry jams with 5, 10 and 20% blueberries in place of strawberry were prepared and evaluated for moisture content, reducing sugar, total acidity, pH, color, total sugar (°Brix), pectin content, anthocyanin content, DPPH radical scavenging activity, texture analysis and sensory characteristics. As the amount of blueberries increased, total acidity, °Brix , reducing sugar content and anthocyanin content of jams increased, while pH decreased, moisture content has changed little. The DPPH radical scavenging activities of the 80% methanol extract from jams were 75.33%, 85.75%, 91.23% and 92.73% at a concentration of 8 mg/mL. Radical scavenging activity increased with the added concentration of blueberries. The lightness decreased with addition of blueberries, but the redness and yellowness increased. The sensory scores for jams increased with the increase of blueberry content; however, strawberry jams with 10% blueberries showed the best scores.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.2
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• pp.49-56
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• 2018

Recently, attempts have been made by dairy farms to shorten the time until the first estrus by feeding animals a high-energy diet during the heifer period. Energy consumption during the heifer period has been shown to be related to milk yield and reproductive performance. The present study was conducted to analyze the relationship between reproductive performance and energy intake in heifers. There were no differences in height or body weight between animals that were fed the Korean standard diet versus a high energy diet (110% of the Korean standard). However, there was a difference in the timing of the first estrus: 329.3 days under normal energy conditions versus 311 days under high energy conditions. There was no difference in the number of artificial insemination per gestation, but both the rate of female calf production and the weight of individual female calves increased in response to the high energy diet. Based on these results, it may be predicted that the reproductive performance of dairy cows will increase when the animals are fed a high energy diet (110% of the Korean standard). These results demonstrate a correlation between the amount of energy consumed and reproductive performance, and will be of great value to the dairy farming industry.

• Journal of Industrial Convergence
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• v.21 no.10
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• pp.81-89
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• 2023

The aim of this study was to explain the mediating effects of self-control in the relationship between academic stress and impulse buying tendency. Participants were recruited from one nursing university student located in Gwangju and J city. Data were collected from 145 nursing university student. The SPSS WIN 23.0 version was used with Sobel test and Baron and Kenny's mediating effect. It was investigated whether there was a mediating effect of self-control on academic stress and impulse buying tendency. First, academic stress showed a significant effect on impulse buying tendency. Second, Self-control had a partial mediating effect in the relationship between academic stress and impulse buying tendency(z=-2.69, p<.001). To reduce the impulse buying tendency among nursing university student, it is necessary to develop education·non-education interventions that promotion self-control in addition to decreasing academic stress.