• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.105-110
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• 2011

BACKGROUND: In this study, 5 different treatments such as non-treatment, mixed expeller cake 1.0 N (standard nitrogen fertilizer), rice straw, rice straw+mixed expeller cake 0.5 N, rice straw+mixed expeller cake 1.0 N were performed over 4 cropping seasons over 2 years in order to identify the optimal application rate of mixture of rice straw and mixed expeller cake, organic source in organic cultivation of tomatoes. METHODS AND RESULTS: There was no difference in all treatments in case of 200 mg/kg in the nitrate nitrogen content in soil prior to the first cropping season test under the criteria for nitrogen nutrient based on yield of crops, cultivation without fertilizers seems possible. But in the second cropping season, no treatment and rice straw showed the reduction of yield and in the third cropping season, rice-straw+mixed expeller cake 0.5 N treatment showed the significant difference. The content of nitrate nitrogen in soil prior to cropping seasons was evaluated in 160 mg/kg and standard fertilization such as mixed expeller cake, source of nitrogen, are needed due to the deficiency of nitrogen. In terms of application of organic resources, rice straw showed the effects of improvements on physical properties of soil such as bulk density, cation exchange capacity and humus contents, but the mixed expeller cake did not show any significant differences in improvements on physical properties of soil. CONCLUSION(s): Fertilizer management in organic cultivation of tomatoes is thought to produce the reliable quantity of crops as well as keep the high quality of soils by using the optimal application rate of mixed expeller cake according to the contents of nitrate nitrogen in soil and rice straw which improves the physical properties of soil.

• Journal of the Korean Wood Science and Technology
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• v.28 no.2
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• pp.57-65
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• 2000

Objective of research is obtain fundamental data of carbonized wood wastes for soil condition, de-ordorization, absorption of water, carrier for microbial activity, and purifying agent for water quality of river. The carbonization technique and the properties of carbonized wood wastes(wood-based materials) were analyzed. Proximate analysis showed the wood-based materials contains 0.37~2.27% ash, 70~74% volatile matter, and 17~20% fixed carbon. As carbonization temperature was increased, the charcoal yield was decreased. However, no difference in charcoal yield was found due to time increase. The specific gravity after the carbonization decreased about 30~40% comparing to green wood. The charcoal had 1.08~4.18% ash, 5.88~13.79% volatile matter, and 80.15~90.94% fixed carbon. The pH of plywood and particleboard(pH 9 at $400^{\circ}C$, pH 10 at $600^{\circ}C$ and $800^{\circ}C$) made charcoals was higher than that of fiberboard. The water-retention capacity was not affected by the carbonization temperature and time. The water-retention capacity within 24h was about 2~2.5 times of sample weight, and the Equilibrium moisture content(EMC) became 2~10% after 24h. EMC of charcoal from the thinned trees were 9.40~11.82%($20^{\circ}C$, RH 90%), 6.87~7.61%($20^{\circ}C$, RH 65%), and 1.69~2.81%($20^{\circ}C$, RH 25%). EMC of charcoal from the wood-based materials under $20^{\circ}C$, relative humidity(RH) 90% was similar to EMC of charcoal from the thinned trees(9~11 %). However, under $20^{\circ}C$, RH 25.65%, EMC of charcoal from the wood-based materials were higher(2~3%) than EMC of charcoal from the thinned trees. Every charcoal from the wood-based materials fulfilled the criteria in JWWA K 113-1947.

• Korean Journal of Plant Resources
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• v.32 no.4
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• pp.338-343
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• 2019

This study was conducted to nominate optimal ground cover plants eventually enhancing Aronia production in the highland rolling plains. Total number of 17 weed species were observed in Aronia field when no cover plant was applied. Meanwhile, 12, 14, 15 and 16 weed species were observed when kentucky bluegrass, white clover, rattail fescue and ground ivy were used, respectively. Untreated native weed species were 73.6 cm tall before cut, and kentucky bluegrass, white clover, Rattail fescue and ground ivy were 57.5, 36.8, 48.3 and 40.9 cm, respectively. Based on plant height before cut, two shortest plants, white clover and ground ivy, were considered effective as ground cover plants in Aronia field. Coverage at $3^{rd}$ year by cover plants ranged from 85% to 100%. Coverage of uncovered Aronia field by native weed species was 95% while coverage by 4 treatments, kentucky bluegrass, white clover, rattail fescue and ground ivy were 100, 87, 85 and 100%, respectively. Aronia yield per plant at $3^{rd}$ year was 1,916 g with white clover cover followed by 1,770 g with Rattail fescue, 1,766 g with ground ivy, 1,098 g without cover plants and 931 g with Kentucky Bluegrass. Out results indicated that ground ivy was the best among all treatments based on 3 criteria, (1) short plant architecture, (2) rapid ground covering and (3) better weed control. In addition, ground ivy cover appeared to secure better yield.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.163-169
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• 2022

This study was conducted to examine an alternative cultivating method that uses coir substrates in a hydroponically cultured system. Three treatment conditions were applied with one-layer substrate (10 cm height) with a coir chip and dust ratio of 5:5 (Treatment A), two-layer coir substrate (20 cm height) with a coir chip and dust ratio of 5:5 (Treatment B), one-layer coir substrate (15 cm height) with a coir chip and dust ratio of 7:3 (Treatment C). The control condition was a plastic container filled with a coir chip and dust ratio of 5:5. Various criteria were measured and compared between the treatments and the control. The yield of strawberry was smaller in the control than in the treatments. No significant difference in growth characteristic was found in the height treatments of the coir substrates. The net photosynthetic rate of the treatments was 14.68-15.76 µmol CO₂·m^-2·s^-1. This does not show a statistically significant difference. The root activity was better in treatment B and C than in treatment A and the control. The length and width of leaves were measured as 4.04-4.13 cm and 3.26-3.34 cm. These results are not statistically significant. The leaf length and width ratio was 1.27 in the control and 1.24 in the treatments. The findings show that no statistically significant benefit was found when utilizing coir substrates with different height treatments in the hydroponic culture system. However, the harvested fruit per plant weights 72.38 g in treatment A and 48.69 g in treatment C. The number of harvested fruit was least in treatment C in which a coir chip and dust ratio of 7:3 was applied. Therefore, further research is needed to examine how the chip and dust ratio in coir substrate affects growth characteristics.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.103-134
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• 1977

The physiological and biochemical role of potassium for upland crops according to recent research reports and the nutritional status of potassium in Korea were reviewed. Since physical and chemical characteristics of potassium ion are different from those of sodium, potassium can not completely be replaced by sodium and replacement must be limited to minimum possible functional area. Specific roles of potassium seem to keep fine structure of biological membranes such as thylacoid membrane of chloroplast in the most efficient form and to be allosteric effector and conformation controller of various enzymes principally in carbohydrate and protein metabolism. Potassium is essential to improve the efficiency of phoro- and oxidative- phosphorylation and involve deeply in all energy required metabolisms especially synthesis of organic matter and their translocation. Potassium has many important, physiological functions such as maintenance of osmotic pressure and optimum hydration of cell colloids, consequently uptake and translocation of water resulting in higher water use efficiency and of better subcellular environment for various physiological and biochemical activities. Potassium affects uptake and translocation of mineral nutrients and quality of products. potassium itself in products may become a quality criteria due to potassium essentiality for human beings. Potassium uptake is greatly decreased by low temperature and controlled by unknown feed back mechanism of potassium in plants. Thus the luxury absorption should be reconsidered. Total potassium content of upland soil in Korea is about 3% but the exchangeable one is about 0.3 me/100g soil. All upland crops require much potassium probably due to freezing and cold weather and also due to wet damage and drought caused by uneven rainfall pattern. In barley, potassium should be high at just before freezing and just after thawing and move into grain from heading for higher yield. Use efficiency of potassium was 27% for barley and 58% in old uplands, 46% in newly opened hilly lands for soybean. Soybean plant showed potassium deficiency symptom in various fields especially in newly opened hilly lands. Potassium criteria for normal growth appear 2% $K_2O$ and 1.0 K/(Ca+Mg) (content ratio) at flower bud initiation stage for soybean. Potassium requirement in plant was high in carrot, egg plant, chinese cabbage, red pepper, raddish and tomato. Potassium content in leaves was significantly correlated with yield in chinese cabbage. Sweet potato. greatly absorbed potassium subsequently affected potassium nutrition of the following crop. In the case of potassium deficiency, root showed the greatest difference in potassium content from that of normal indicating that deficiency damages root first. Potatoes and corn showed much higher potassium content in comparison with calcium and magnesium. Forage crops from ranges showed relatively high potassium content which was significantly and positively correlated with nitrogen, phosphorus and calcium content. Percentage of orchards (apple, pear, peach, grape, and orange) insufficient in potassium ranged from 16 to 25. The leaves and soils from the good apple and pear orchards showed higher potassium content than those from the poor ones. Critical ratio of $K_2O/(CaO+MgO)$ in mulberry leaves to escape from winter death of branch tip was 0.95. In the multiple croping system, exchangeable potassium in soils after one crop was affected by the previous crops and potassium uptake seemed to be related with soil organic matter providing soil moisture and aeration. Thus, the long term and quantitative investigation of various forms of potassium including total one are needed in relation to soil, weather and croping system. Potassium uptake and efficiency may be increased by topdressing, deep placement, slow-releasing or granular fertilizer application with the consideration of rainfall pattern. In all researches for nutritional explanation including potassium of crop yield reasonable and practicable nutritional indices will most easily be obtained through multifactor analysis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.139-144
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• 1969

1. In order to obtain useful mutants such as early maturity, resistance to lodging, high protein and oil content, and capability of high yield, dormant seeds of two soybean varieties, Jang Dan Baik Mok and Clark, were treated with ${\gamma}$-ray, Ethyl Methane Sulfonate(EMS), Ethylene Imine(EI)and combinations of ${\gamma}$-ray and EMS or EI. 2. The germination rate and survival rate in a variety Jang Dan Baik Mok were significantly decreased with ${\gamma}$-ray treatment while it was not the same in the Clark variety. A significant decrease for seedling height measured at 14 and 21 days after sowing was found with the increase of ${\gamma}$-ray dose in both varieties. 3. Germination rates in both varieties were significantly decreased as EI concentration increases, particularly severe damage in germination was observed at 0.008 Mo. concentration. Germination rate damages were found with EMS concentration increases in the variety Jang Dan Baik Mok while no regular responses in seedling height were observed in the variety Clark. 4. Germination rate was significantly lowered with the combined treatment of EMS and ${\gamma}$-ray 24KR than that of EMS alone. In the treatments of ${\gamma}$-ray with three levels of EI concentration, the combined treatments except 24KR+EI 0.002 Mol. resulted in better germination than of EI alone. In both varieties, significant reduction in seedling height was observed in the combined treatments of ${\gamma}$-ray with various concentrations of EMS, whereas stimulation effect on seedling height was found with treatment of ${\gamma}$-ray EI +0.08Mol. 5. Germination rate, survival rate, and plant height as criteria of radio sensitivity, variety Jang Dan Baik Mok is moze sensitive to ${\gamma}$-ray, EMS, and EI than the variety Clark, and the varietal difference in responsibility to mutagen may be due to the genetic-constitution of the varieties.

• 대한공업교육학회지
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• v.39 no.2
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• pp.101-121
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• 2014

The study aims to develop the NCS based vocational curriculum model for the practical and creative human resources. For effectiveness of the study, the study consists of literature studies of both domestic and international, contents analysis, case study, expert(9samples) consultation and review, and in-depth-interview of the three advisory members. The validity of the developed model is analyzed through mean, standard deviation and contents validity ratio(CVR). The main results of the model development in our study are as follow. First, our NCS based vocational curriculum model for the practical and creative human resources is developed with the analyses of NCS development manuals, training standard utilization and training curriculum organization manuals, NCS learning module development manual and case studies, NCS research report, NCS based curriculum pilot development resources directed toward the high schools and vocational school as well as the domestic and international literature study on career training model like NCS. Second, based on the findings of our analysis in combination with the findings from the consultations with the expert and advisory committee, total 19 sub-factors of each step and domain are extracted. The sub-factors of domain in step 1 are the competency unit, definition of competency unit, competency unit element, performance criteria, range of variable, guide of assessment, key competency; in step 2, they are subject title, subject objectives, chapter title, chapter objectives, pedagogical methods, assessment methods and basic job competence; and in step 2, they are NCS based subject matrix table, NCS based subject profile, NCS based job training curriculum table, NCS based subjects organization flowchart, NCS based job training operation plan. Third, the final model including step 3 NCS based subject profile are developed in association with the linked organizational sub-factors of step 1 and step 2. Forth, the validity tests for the final model by the step and domain yield the mean 4.67, CVR value 1.00, indicating the superior validity. Also, the means of each sub-factors are all over 4.33 with the CVR value 1.00, indicating the high validity as well. The means of the associated organizations within the model are also over 4.33 with the CVR value of 1.00. Standard deviations are all .50 or lower which are small. Fifth, based on the validity test results and the in-depth-interview of the expert and advisory committee, the model is adjusted complemented to establish final model of the NCS based vocational curriculum for the practical and creative human resources.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.3
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• pp.165-181
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• 1976

Fertilizer(N,P,K) demand for crop production in 1980, 1990 and 2000 was estimated according to the two proposed models, one of which is fertilizer use efficiency model expressed in $Fn=(Y/E){\cdot}(1-Cs)Eu$, where Fn:fertilizer demand, Y:Crop production estimated, E:nutrient efficiency, Cs:fraction of natural resource nutrient in plant, Eu:fertilizer use efficiency and the other fertilization efficiency model expressed in Fn=Y(1-Cys)/Fe, where Cys:fraction of yield without fertilizer, Fe:fertilization efficiency. Total crop uptake of nutrient and its noncycling portion were estimated as criteria for fertilizer demand and nutrient maintenance. Total crop uptake of N,P,K was 600,000 M/T in 1965 700,000 M/T in 1974 and estimated to 880,000 M/T in 1980, 1,170,000 M/T in 1990 and 1,410,000 M/T in 2000. Fertilizer demand appeares to be about 90% of total crop uptake according to fertilizer use efficiency model and about 87% according to fertilization efficiency model. The noncycling nutrient was about 29% of total crop uptake. Fertilizer demand was almost same to the uptake amount in nitrogen, 1.5 times of uptake in phosphorus and half of uptake in potassium. Varietal development, improvement of soil fertility and cultivation method and development of fertilizer forms appears to decrease fertilizer demand by increasing efficiency term in two models while environmental stress such as low temperature appears to give reverse effect resulting in higher fertilizer demand. Fertilizer consumption in 1974 seemed to be unreasonably high especially in nitrogen and phosphorus and thus the effective use of fertilizer appeared as an urgent problem considering that large fields are still remained in lower fertility.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.477-483
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• 2012

This study was carried out to investigate the influence of copper concentrations in fertilizer solution on the growth of and nutrient uptake by domestically bred strawberries. The characterization of toxicity symptoms as well as tissue analyses based on dry weight of above ground tissue were also conducted to determine the threshold levels in plants when toxicity developed in copper. The dry weights of the above ground tissue were not significantly different among the treatments of 0.25 mM to 1.0 mM in 'Keumhyang' and 'Maehyang' strawberries and that of 0.25 mM to 3.0 mM in 'Seolhyang' strawberry. This indicates that the 'Seolhyang' strawberry is more tolerant to copper toxicity than 'Keumhyang' or 'Maehyang' strawberries. Application of copper at high concentrations resulted in severe toxicity such as death of extensive areas of leaves. The lower leaves became yellow and die rapidly as the symptoms spread up the plants. The leaf blades and petioles died back to the crown and hang on by mechanical attachment. Symptoms of copper toxicity in lower leaves developed as browning on leaf margins and in patches between leaf veins that became necrotic. The elevation of copper concentrations in fertilizer solution did not influence the tissue phosphorus, potassium, calcium, and magnesium contents based on the dry weight of the above ground tissue. The tissue copper contents increased lineally as the copper concentrations in fertilizer solution were elevated. But the tissue iron, manganese and boron contents were not influenced by the concentrations. When the concentration of copper at which growth of a plant is retarded by 10% is regarded as threshold level, the copper contents based on dry weight of above ground plant tissue should be lower than 71.4, 57.9 and 74.8 $mg{\cdot}kg^{-1}$ in 'Keumhyang', 'Maehyang' and 'Seolhyang' strawberries, respectively. The symptom characterization and established threshold level in copper toxicity would help growers to prevent the reduction of crop growth and yield in 'Seolhyang' strawberry cultivation.

• Journal of Korean Society of Forest Science
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• v.94 no.1 s.158
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• pp.34-38
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• 2005

This study, basic research for releasing new chestnut cultivar, is conducted to consider quantitative nut characteristics according to combinations and individuals In 11 chestnut hybrids. Number of bur on bearing branch(NBB) and nut yield(NY), which showed large difference among combinations, was superior in JO ($Joook{\times}Otanba$) and KO ($Kwangeun{\times}Otanba$) combinations, respectively. Average nut weight (NW) was 21.1g, the highest in EO ($Eunsan{\times}Otanba$) combination. Nut shape which was expressed to the rate of nut height and width, was investigated to the range of 1.13-1.23 in the all combinations, so nut shape of all combinations showed oval type. EO and JO combinations, which were measured to 30.0% and 27.5%, respectively in the percentage with the pericarp split(PPS), were produced more bad fruits than the others. OK ($Otanba{\times}Kwangeun$) combination, 1.7%, was the most excellent in the percentage of polyembryonic nuts(PPN), and the superior combinations which was measured to the below 5%, could be included five combinations. ER and RK combinations, were the highest values, 16.3% and $10.0kg/cm^2$, in soluble solids content(SSC) and kernel hardness (KH), respectively. NBB showed highly positive correlation with NY, but showed highly negative correlation with SSC and NW. NW showed highly positive correlation with PPS, but showed highly negative correlation with SSC and NH. PPS showed highly positive correlation with PPN. Eight individuals such as superior individuals could be selected by selection criteria.