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

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.5
• /
• pp.704-710
• /
• 2012

The lower portion of sloping paddy fields normally contains excessive moisture and the higher water table caused by the inflow of ground water from the upper part of the field resulting in non-uniform water content distribution. Four drainage methods namely Open Ditch, Vinyl Barrier, Pipe Drainage and Tube Bundle for multiple land use were installed within 1-m position from the lower edge of the upper embankment of sloping alluvial paddy fields. This study was conducted to evaluate soil physical characteristics by drainage improvement in poorly drained sloping paddy field. The results showed that subsurface drainage by Pipe Drainage improves the productivity of poorly drained soils by lowering the water table and improving root zone soil layer condition. In an Pipe drainage plot, soil moisture drained faster as compared to the other drainage methods. Infiltration rate showed high tendency to Piper Drainage method about $20.87mm\;hr^{-1}$ than in Open Ditch method $0.15mm\;hr^{-1}$. And Similarly soil water and degree of hardness and shear strength phase of soil profile showed a tendency to decrease. From the above results, we found that when an subsurface drainage was established with at 1m position from the lower edge paddy levee of the upper field in sloping poorly drained paddy fields Pipe Drainage was the most effective drainage system for multiple land use.

• Asian Journal of Turfgrass Science
• /
• v.26 no.1
• /
• pp.24-34
• /
• 2012

The study was carried out to investigate the effects of polymer, calcium, perlite and chitosan on the growth of perennial ryegrass (Lolium perenne L., PR) and to provide a basic information needed for their practical application when establishing garden, parks, athletic field and golf courses with these materials. A total of 24 treatment combinations were applied in the study. Treatments were made of water-swelling polymer (WSP), calcium, perlite and chitosan mixed in soil organic amendment (SOA). Germination rate, turfgrass coverage, turfgrass density and top growth were evaluated in PR under greenhouse conditions. Significant differences were observed for these growth characteristics among the treatments. Turfgrass density and plant height, evaluated on a weekly basis, varied with time after seeding. A proper mixing rate of WSP was considered to be lower 3% for the growth of PR with an exception of being below 6% for turfgrass density. Germination rate and early survival capacity were greatly influenced by calcium and chitosan among the elements of calcium, perlite, and chitosan. But there was little effect by perlite. Calcium and chitosan were most effective one for turfgrass density and coverage, respectively. Top leaf-growth was influenced by all three elements, but the greatest effect was highly linked with calcium. Chitosan was very effective in early germination and vertical leaf growth, as compared with the others. Future studies are required for measuring the effect of WSP, calcium, perlite and chitosan on the turf growth characteristics in root zone mixtures of sand+SOA before a practical field use.

• Journal of Life Science
• /
• v.20 no.8
• /
• pp.1254-1260
• /
• 2010

Microorganisms near the plant rhizosphere usually inhabit the surface or the inside of the plant roots and have a direct effect on plant growth by secreting plant growth promoters or antagonistic materials which protect the root zone system from various pathogens. This study was carried out to identify and isolate the antagonistic materials after isolation of microorganisms showing high antagonistic activities, in hopes of contributing to the development of sustainable agriculture and the preservation of agricultural environments. A number of antagonistic bacteria were isolated from paddy soil. Among isolates, RRj 228 showed plant growth promotion and antagonistic activity. RRj 228 was identified as Pseudomonas sp. according to the results of physiological properties and genetic methods. On the basis of the results of anti-fungal spectrum against several pathogens by RRj 228, the antagonistic effect of the isolate against Botrytis cinerea, Pythium ultimum, Phytopthola capsici, and Rhizoctonia solani, especially against red-pepper anthracnose caused by Colletotrichum acutatum, was remarkable. The experiment evaluating the biological control effect by RRj 228 revealed that the $ED_{50}$ value by the RRj 228 culture against C. acutatum, R. solani and P. ultimum were 0.14 mg/ml, 0.16 mg/ml and 0.29 mg/ml, respectively. An antagonistic substance was isolated and purified by several chromatographies from the RRj 228 culture. The $^1H$ and $^{13}C$ assignment of the antagonistic substance was achieved from two-dimensional $^1H-^1H$ COSY, HMQC, and HMBC. Finally, the antagonistic substance was identified as Phenazine-1-carboxylic acid ($C_{13}H_8N_2O_2$, M.W.=224).

• Journal of Korean Society of Forest Science
• /
• v.103 no.4
• /
• pp.593-598
• /
• 2014

In this study, we developed the carbon emission factors for 4 major species of warm-temperate region in Korea, and tried to provide their carbon emissions and removals estimates using these carbon emission factors. We selected Castanopsis cuspidata, Camellia japonica, Quercus acuta and Quercus glauca as target species and derived their carbon emission factors. The basic wood density that serve as one of the carbon emission factors were 0.583 for Castanopsis cuspidata, 0.657 for Camellia japonica, 0.833 for Quercus acuta and 0.763 for Quercus glauca and their uncertainties ranged from 5.3 to 17.9%. Biomass expansion factors were calculated as well: 1.386 for Castanopsis cuspidata, 2.621 for Camellia japonica, 1.701 for Quercus acuta and 2.123 for Quercus glauca and associated uncertainties varied from 14.7 to 30.5%. Lastly root-shoot ratios for each species were also determined: 0.454 for Castanopsis cuspidata, 0.356 for Camellia japonica, 0.191 for Quercus acuta and 0.299 for Quercus glauca with the uncertainties lying within a range from 19.8 to 35.7%. These three carbon emission factors including basic wood density had the uncertainties of less than 40% recommended by FAO. Therefore the application of country-specific emission factors seemed to provide quite accurate estimates of carbon emissions and removals. The estimation of the carbon stored in the 4 species were also conducted which amounted to $186.10tCO_2/ha$ for Castanopsis cuspidata, $280.63tCO_2/ha$ for Camellia japonica, $344.04tCO_2/ha$ for Quercus acuta and $278.91tCO_2/ha$ for Quercus glauca and their annual carbon removals were $6.65tCO_2/ha/yr$, $6.25tCO_2/ha/yr$, $11.70tCO_2/ha/yr$ and $12.29tCO_2/ha/yr$, respectively. This systematic assessment of forest resources can be a reliable source of information for managing evergreen broadleaved forest in warm temperate regions and thus serve as useful data for effective decision-making to address vegetation zone shifts due to climate change.

• The korean journal of orthodontics
• /
• v.31 no.3 s.86
• /
• pp.369-379
• /
• 2001

The aim of this study was to investigate the periodontal response according to the timing of orthodontic force application after bone graft into the angular bony defect. Nine dogs were divided into three groups, 2, 4, and 6 weeks, according to the timing of orthodontic force application after bone graft. Periodontal angular bony defects were created surgically at the distal aspect of both maxillary third incisors. Two weeks later, flap operation was performed to eliminate inflammation and reference notch was made on the root surface at the level of the bottom of each defect. Demineralized freeze-dried bone was implanted on the left side whereas only debridement was done on the other side. Experimental tooth movement was executed during 8 weeks on both graft and non-graft sides. After 2 weeks of retention period, animals were sacrificed for histologic specimens. The results were obtained as follows 1 New bone formation was more pronounced in the graft side than in the non-grad side in all experimental animals. 2. In the 6-week group, new bone and cementum formation was observed in more than half from the notch to the cemento-enamel junction, and the zone of connective tissue attachment was found without apical migration of junctional epithelium. 3. In the 4-week group, the amount of new bone formation was smaller than in the 6-week group whereas the overall remodeling pattern was similar. 4. New bone formation was confined to around the notch and the junctional epithelium migrated apically to the level of the notch with no connective tissue attachment and cementum formation in the 2-week group. The results of the present study suggest that periodontal response may be influenced by the timing of orthodontic force application after bone graft into angular bony defect.

• Journal of Bio-Environment Control
• /
• v.23 no.2
• /
• pp.139-143
• /
• 2014

This study was conducted to investigate the effect of cultivation period and rockwool block size on the growth and early yield of paprika transplants grown in a closed transplant production system. Paprika seeds were sown and germinated in three different size of rockwool blocks ($45{\times}40{\times}35$, $70{\times}70{\times}60$, $100{\times}100{\times}65mm$) and cultivated in a closed transplant production system for 23, 30, and 37 days after sowing. Paprika transplants were cultivated using $100{\times}100{\times}65mm$ rockwool blocks in a greenhouse following a conventional and typical production method for comparing with the growth of paprika transplants grown in a closed transplant production system. Also, we transplanted paprika transplants grown for 23, 30, and 37 days in a closed transplant production system and greenhouse to rockwool slabs and investigated fresh weight of fruits and yield 125 days after sowing. The growth of paprika transplants grown in $70{\times}70{\times}60mm$ rockwool blocks in a closed transplant production system was highest, and the quality of paprika transplant grown in a closed transplant production system was better than in a greenhouse. Rockwool block size and cultivation period in a closed transplant production system did not affect fresh weight of fruits, however, yield was largest when paprika transplants were cultivated using $70{\times}70{\times}60$ and $100{\times}100{\times}65mm$ rockwool blocks for 23 days in a closed transplant production system. These results suggest that decreasing rockwool block size and cultivation period can be strategically used to enhance transplant quality and yield of paprika, as paprika transplants were cultivated in a closed transplant production system.

• Journal of Bio-Environment Control
• /
• v.18 no.1
• /
• pp.1-8
• /
• 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 Bio-Environment Control
• /
• v.7 no.1
• /
• pp.43-54
• /
• 1998

This experiment was conducted to develop optimal nutrient solution for tomato plants, according to the plant growth stages in closed system. Perlite substrate was supplied with 1/2 and 1 strength of the solution of National Horticultural Research Station in Japan. Plants grew better and the nutrient_contents in the leaves were also proper in 1 strength. Based on these results, optimal nutrient solution in perlite was composed by n/w of 1 strength according to the plant growth rates ： N 13.5, P 3.3, K 7.0, Ca 7.0, Mg 3.5 me.L$^{-1}$ in seedling stage, N 14.2, P 3.3, K 8.0, Ca 7.5, Mg 4.0 me.L$^{-1}$ in vegetative stage and N 10.0, P 3.0, K 7.0, Ca 6.0, Mg 3.0 me.L$^{-1}$ in reproductive stage. To examine the suitability of the nutrient solution developed in this experiment, tomato plants were grown in rockwool and supplied with two different composition and concentration of nutrient solution composed by n/w of 1 strength in perlite (SCUT) and by Research Station for Greenhouse Vegetable and Floriculture on the Netherlands (PBG). PH and EC in SCUT were changed little in 1 strength but a significant change of PH was shown in 1/2 strength. Later, drained solutions in rockwool were also analyzed according to the Plant growth stages. Low concentrations of N and P in root zone were shown in early growth stage but N was increased in reproductive stage, while, K, Ca, Mg concentration was consistent through the whole growth stage. Considering these results, we found that the rebalance of N and P was needed, that is, reduction of N concentration in reproductive stage and increasing of P concentration in vegetative stage.

• Journal of Bio-Environment Control
• /
• v.7 no.1
• /
• pp.15-24
• /
• 1998

The greenhouse temperature controls in general have been managed by the above-ground part environment, But the temperature of root zone was known very important factor for the 9rofth and the yield of vegetables in greenhouse. The purpose of this study is to develop a good method for cultivation using solar energy which can apply warming soil and to develop the greenhouse soil temperature automatic control system. Followings are summary of this study：1 When the greenhouse inner temperature changes were about 24$^{\circ}C$ during a day in October, the temperature of non-warmed soil was differenced 6$^{\circ}C$ in the depth 10cm and 3$^{\circ}C$ in the depth 20cm. 2. When water supply temperature was kept at 40, 50 and 6$0^{\circ}C$, the lowest soil temperature in the depth of 10cm is 2$0^{\circ}C$ and that of 20cm was 23$^{\circ}C$. and when the water supply temperature was over 4$0^{\circ}C$, the space heating temperature did not affect the temperature variation of soil. 3. In comparison with conditions of the warmed and non-warmed soil, when the water supply temperature is 28$^{\circ}C$, soil temperatures had the high temperature of 4$0^{\circ}C$~7$^{\circ}C$ in the depth of 10cm to 20 cm. 4. The line of boundary area was appeared in the depth of 15~20cm, 13~19cm and 12~17cm. when the water supply temperature was 4$0^{\circ}C$, 5$0^{\circ}C$ and 6$0^{\circ}C$. 5. When th inner greenhouse air temperature is maintained over 11$^{\circ}C$ and the water supply temperature is supported 28$^{\circ}C$, the lowest temperature is kept up over 2$0^{\circ}C$.