• Journal of Bio-Environment Control
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• v.15 no.3
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• pp.250-256
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• 2006

This experiment was conducted to investigate the hydroponic culture possibility and the optimal solution strength of 'Pechika' ever-bearing strawberry in summer highland. Maximum room temperature and minimum root zone temperature of plastic house were $30.8^{\circ}C\;and\;19^{\circ}C$ in highland respectively and $4^{\circ}C\;and\;3^{\circ}C$ lower than in level and. The growth of 'Pechika' was better in highland. There was effective in producing the good yield and fruit quality in highland and the deformed fruits also were decreased. The soluble solid and titratable acidity content increased in highland. Early growth was the most effective in standard solution $(EC\;0.75dS\;m^{-1})$ and had a tendency to be inhibition with increasing nutrient concentration. Standard solution was also the highest to yield about 2,064kg/10a among treatments, and 2/3S, 4/3S, 5/3S by turns. The browning roots and root activity increased when the solution strength was increased, especially in EC $1.25dS{\cdot}m^{-1}$. The soluble solids and acidity content of fruits were increased with higher solution strength. Therefor, the summer hydroponic culture of 'Pechika' ever-bearing strawberry was suitable in highland and effective in standard solution $(EC\;0.75dS{\cdot}m^{-1})$ in solution control.

• Journal of Bio-Environment Control
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• v.20 no.1
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• pp.21-26
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• 2011

Differences among cultivars, conditions of nutrient solution, nursing materials, and soilless culture systems were investigated to select suitable cultivar and cultivation methods for stable production of summer spinach in the highlands. The 'Quinto' spinach showed the earliest growth and highest yield. For yield increase of summer spinach, optimal solution pH was 6.0, EC was $2.0dS{\cdot}m^{-1}$, and $NH_4-N$ ratio of nutrient solution was 30 percent Stand rate of spinach in nursing seedlings, at 200-cell-tray filled with mixed nursing soil (peat : perlite = 7 : 3), was higher than those grown in urethane sponge and rock-wool plug. Yield was also 18 to 24 percent higher than those in rock-wool plug and urethane sponge. Plant length and yield of spinach in mixed substrate (peat : perlite = 7 : 3) filled nutrient film technique (MSNFT) system were longer of 18 percent, and higher of 9 percent than those in deep flow technique (DFT) system, respectively. However, changes of root zone temperature, pH and EC showed similar pattern with DFT. Therefore, growing 'Quinto' cultivar at 6.0 of pH, $2.0dS{\cdot}m^{-1}$ of EC, 30 percent of $NH_4-N$ ratio, at 200-cell-tray filled with mixed nursing soil, and MSNFT cultivation system, was the best for production of summer spinach in the highlands.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.2
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• pp.59-69
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• 2019

This study was carried out to investigate effects of soil water content on growth and antioxidative enzymes activity of tomato seedlings during the nursery period. The water stress significantly damages morphological, physiological, and biochemical activities in plants. The seedlings planted with soil on the tray were irrigated and categorized into 3 groups with 30 g, 40 g, and 50 g of plant-soil weight. After then, the changes in weight of the soil and the seedling were measured evey 2 hours for 4 days and the leaf temperature was measured with the thermal-camera at the same time. The antioxidant enzymes were measured to determine the level of stress using all of the seedling samples. The result showed that the decrease of soil weight in the day time was faster than that in the night time, but there was no significant difference in the weight loss of the seedlings and soil among the groups. However, the group with 50 g of wight showed the highest SOD and POD contents. This is considered that the continuously wet soil on the root zone of the seedlings caused more stress for the seedlings. Therefore, it is concluded that the excess moisture content causes stress to stimulate the secretion of antioxidant enzymes, and the effect of stress is required to be analyzed comprehensively using environmental data and also the physiological data that are collected over a longer period.

• Journal of Bio-Environment Control
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• v.18 no.1
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• pp.1-8
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• 2009

The greatest and major cost for cut rose production during winter seasons in Korea is cost of heating the greenhouse. A study was conducted on a cost-efficient heating system to reduce expenses of cut rose growers in times of high energy prices. An infrared heating system utilizing radiant energy has an obvious advantage over other heating methods in that the energy is first used to raise temperatures of plants and other objects and subsequently that of the atmosphere, resulting in faster reaching to desired plant temperatures at a reduced heating cost. In this study the heating effect and heating cost saving of a nano-carbon fiber infrared heating system (NCFIHS) installed in cut rose greenhouses in Gimhae, Gyeongnam Province were analyzed comparatively. In addition growth, quality, and vase life of 'Orange Fresh' roses grown in greenhouses heated by NCFIHS against those grown in greenhouses heated by so called an electrical heating system. In greenhouses with a NCFlHS with a set point air temperature of $20^{\circ}C$, plant temperature was maintained at $1{\sim}2^{\circ}C$ higher than the air temperature, and temperatures of growing bed surface and root zone were maintained at $17{\sim}19^{\circ}C$ throughout cold winter nights. The cost for heating in NCFIHS was about 25 and 51% of that of an electrical heating system and a hot water heating system heated by petroleum, respectively. Growth of roses harvested in greenhouses with a NCFIHS was similar to those grown in greenhouses with an electrical heating system. However, cut roses with more intense petal and leaf colors and a longer vase life (fresh weight and amount of water uptake) were harvested in greenhouses with a NCFIHS as compared to those harvested in greenhouses with an electrical heating system.

• Journal of Korean Society of Forest Science
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• v.62 no.1
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• pp.24-42
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• 1983

To develop Ilex cornuta which grow naturally in the southwest seaside district as new ornamental tree, the author chose I. cornuta growing in the four natural communities and those cultivated in Kwangju city as a sample, and investigated its ecology, morphology and characteristics. The results obtained was summarized as follows; 1) The natural distribution of I. cornuta marks $35^{\circ}$43'N and $126^{\circ}$44'E in the southwestern part of Korea and $33^{\circ}$20'N and $126^{\circ}$15'E in Jejoo island. This area has the following necessary conditions for Ilex cornuta: the annual average temperature is above $12^{\circ}C$, the coldness index below $-12.7^{\circ}C$, annual average relative humidity 75-80%, and the number of snow-covering days is 20-25 days, situated within 20km of from coastline and within, 100m above sea level and mainly at the foot of the mountain facing the southeast. 2) The vegetation in I. cornuta community can be divided that upper layer is composed of Pinus thunbergii and P. densiflora, middle layer of Eurya japonica var. montana, Ilex cornuta and Vaccinium bracteatum, and the ground vegetation is composed of Carex lanceolata and Arundinella hirta var. ciliare. The community has high species diversity which indicates it is at the stage of development. Although I. cornuta is a species of the southern type of temperate zone where coniferous tree or broad leaved, evergreen trees grow together, it occasionally grows in the subtropical zone. 3) Parent rock is gneiss or rhyolite etc., and soil is acidic (about pH 4.5-5.0) and the content of available phosphorus is low. 4) At maturity, the height growth averaged $10.48{\pm}0.23cm$ a year and the diameter growth 0.43 cm a year, and the annual ring was not clear. Mean leaf-number was 11.34. There are a significant positive correlation between twig-elongation and leaf-number. 5) One-year-old seedling grows up to 10.66 cm (max. 18.2 cm, min. 4.0 cm) in shoot-height, with its leaf number 12.1 (max. 18, min), its basal diameter 2.24 mm (max. 4.0 mm, min. 1.0 mm) and shows rhythmical growth in high temperature period. There were significant positive correlations between stalk-height and leaf-number, between stalk-height and basal-diameter, and between number and basal diameter. 6) The flowering time ranged from the end of April to the beginning of May, and the flower has tetra-merouscorella and corymb of yellowish green. It has a bisexual flower and dioecism with a sexual ratio 1:1. 7) The fruit, after fertilization, grows 0.87 cm long (0.61-1.31 cm) and 0.8 cm wide (0.62-1.05 cm) by the beginning of May. Fruits begin to turn red and continue to ripen until the end of October or the beginning of November and remain unfading until the end of following May. With the partial change in color of dark-brown at the beginning of the June fruits begin to fall, bur some remain even after three years. 8) The seed acquision ratio is 24.7% by weight, and the number of grains per fruit averages 3.9 and the seed weight per liter is 114.2 gram, while the average weight of 1,000 seeds is 24.56 grams. 9) Seeds after complete removal of sarcocarp, were buried under ground in a fixed temperature and humidity and they began to develop root in October, a year later and germinated in the next April. Under sunlight or drought, however, the dormant state may be continued.

• Journal of Bio-Environment Control
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• v.15 no.3
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• pp.257-263
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• 2006

This experiment was conducted to investigate the optimal media for 'Pechika' ever-bearing strawberry grown in hydroponic culture system in summer highland. Three mixed media (1:1, v/v) of peatmoss with perlite, rice hull, and granular rockwool, and four solution strengths of EC 0.5, 0.75, 1.0 and $1.25 dS{\cdot}m^{-1}$ were tested. Root zone temperature in peatmoss+perlite media was 1 to $3^{\circ}C$ lower than in the other media. The culture medium of mixing to peat moss and perlite was most effective in producing good yield and fruit quality. The culture medium of mixing to peat moss and perlite was the highest about 1,632kg/10a to yield yearly average, but was very undulating 732 kg/10a to yield in 2004 year and 3,013kg/10a in 2003 year. The deformed fruits were increased when the solution strength was increased, especially in EC $1.25dS{\cdot}m^{-1}$. The soluble solids and the acidity content of fruits were increased with higher solution strength regardless of media. The uptake of Ca and Mg was inhibited at higher solution strength, and the uptake of N, P and K was promoted. Therefore, the culture medium of mixing to peat moss and perlite was the most suitable culture medium to product strawberry in summer, because it had the highest yield even though fruit quality among treatments was not significant.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.3
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• pp.3059-3088
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• 1973

The Object of research was laid on the dry paddy field which had a low level of underground water, rather than on a paddy field with a high level of underground water. In the treatment of the clay paddy field before transplanting we employed 3 kinds of methods; deep plowing, development of cracks by drying the surface of the field under which pipe drain was built. This study was to find which one, among these three methods, is the most effective to let roots extend to deep zone and increase the yield of rice and at the same time, for trafficability of large scale machinery which will be introduced to the harvest, in the light of the earth bearing capacity in relation with underground drainage. In the treatments of plots, 1) the kyong plot was plowed 39 days before transplanting and dried, 2) the kyun plot was plowed again 2days before transplanting after plowing 39 days before transplanting, leveling field surface in the saturation with water and developing the cracks by drying, 3) the kyunam plot was plowed again 2 days before transplanting after setting the drainage pipe and at the same time plowing 39 days before transplanting, leveling field surface in the saturation with water and developing the cracks by drying. Also each plot above had three different levels of soil depth, respectively; that is 15cm, 25cm, 35cm. The kyong plot with 15cm-depth was he control. The results obtained were as follows; 1. The kyunam plot showed a remarkably lager amount of water consumption by better underground drainage than the kyong and the kyun plot, and the kyong plot indicated a greater amount of water consumption than the kyun plot. Therefore the amount of available rainfall was decreased in the order of kyunam>kyong>kyun. The net duty of water decreased in the order of kyunam>kyong>kyun and its showed about 105cm in depth at the kyunam plot, about 70cm in depth at the kyong plot and about 45cm in depth at kyun plot, regardless of soil depth. 2. According to the tendency that the weight of the total root was effected by the maximum depth of the crack, it seemed that the root development was more affected by the depth of the crack than by only the crack itself. The weight of the total roots tended to increase as the depth of the crack got deeper and deeper, and the weight of the total roots was increased in the order of kyun<kyunam<kyong. 3. In the growing of the plant height, the difference did not appear at the beginning of growing(peak period of tillering) of any plot, But for the mid period of growing(ending period of tillering) to the period of young panicle formation, the deeper the depth of plot is, the more the growing goes down. On the contrary at the late period of growing, growth was more vigorous in the plot with deep depth than in the plot with shallow depth. Since the midperiod of growing, in the light of experimental treatment, the kyun plot was not better in growing than the other two plots and no remarkable defference was shown between the kyunam and the kyong plot, but the kyunam plot had the tendency of superiority in growing plant height. 4. As the depth of plot went deeper, the decreasing tendency was shown in the number of tillers through a whole period of growingi. When the above results were observed concering each plot of experimental treatment, the kyun plot was always smaller in the number of tiilers than the kyunam and the kvong plot, and the kyong plot was slightly larger than the kyunam plot in the number of tillers. 5. When each plot of the different experimental treatments was compared with the control plot(15-kyong), yield(weight of grains) was increased by 17% for the 35-kyong plot, by 10% for the 35-kyunam and yields for the other plots were less or nomore than the control plot. On the whole, as the depth of plot went deeper, yields for plots was increased in the order of kyong>kyunam>kyun. 1% of significance between the levels of depths and 5% of significance between the treatments were shown. 6. The depth of consumptive water which was more effective on the weight of grains is that of the last half period. When the depth of consumptive water was increased at the range of less than 2.7cm/day in the 15cm plot, 3.0cm/day in the 25cm plot and 3.3cm/day in the 35cm plot, the weight of grains was increased, and at the same time the weight of grains was increased as the depth of plot went deeper. The deeper plots was of advantage to the productivity at the same depth of consumptive water. 7. The increase in the weight of grains in propertion to the weighte of root showed a tendency to increase depending on the depth of plot at each plot of the same weight of roots. The weight of roots and grains together increasezd in the order of kyun>kyunam>kyong, considering each treatment of experimental plot. The weight of grains was in relation to the minimum water content ratio during the midperiod of surface drainage and the average earth temperature was mainly affected by the minimum water content ratio because it was relatively increased in proportion to the water content ratio(at less than 40%) 8. The weight ratio of straw to grain showed an increasing tendency at the plot of shallow depth and had a relation of an inversely exponental function to the weight of roots. At the same depth of plot except the 15cm plot, the weight ratio of straw to grain was increased in proportion to the depth of consumptive water. The weight of grains was increased as the depth of consumptive water was increased to some extent, but at the same time the weight of ratio of straw to grain was increased. 9. At a certain texture of soils the increase in the amount of the cracks depends on meteorological conditions, especially increase in amounts of pan evaporation. So if it rains during the progressing of field drying the cracks largely decrease. The amount of cracks of clay soil had relation of inversely exponental function to the water content ratio(at more than 25%). The maximum depth of crack kept generally a constant value at less than 30% of water content ratio. 10. The cone index showed the tendency that it was propertional to the amount of cracks within a certain limit but more or less inversely proportional over a certain limit. The water content ratio at the limit may be about 25%. 11. The increase in the cone index with the progressing of time after final surface drainage showed the tendency that it was proportional to the depth of consumptive water at the last half of growing period. Based on the same depth of if the cone index in the kyunam plot was much larger than in the other two plots and that in the kyong plot was much smaller than in the kyun plott, as long as the depth of plot was deeper, especially in the 35-kyong plot. 12. In the light of a situation where water content ratio of soil decreased and the cone index increased after final surface drainage the porogress of the field dryness was much more rapid in the kyunam plot than in the kyong plot and the kyun plot, especially slowest in the kyong plot. In the plot with deeper zone the progress was much slower. The progress requiring the value of the cone index, $2.5kg/cm^2$, that working machinary can move easily on the field changed with the time of final surface drainage and the amount of rainfall, but without nay rain it required, in the kyunam plot, about 44mm in total amount of pan evaporation and more than 50mm in the other two plots. Therefore the drying in the kyunam plot was generally more rapid in the kyunam plot was generally more rapid over 2days than in the kyun plot, and especially may be more rapid over 5days than in the 35-kyong plot.