• Horticultural Science & Technology
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• v.29 no.2
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• pp.102-109
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• 2011

This research was conducted to establish efficient methods to control root-zone temperature of tomato plant when cultivated in perlite bag during the summer season. Tomato plants were grown with four selected treatments; covering irrigation pipe by aluminum insulation material (Insulate), discarding nutrient solution inside the irrigation line before each irrigation (Discard), skipping irrigation for two hours from 13:00 to 15:00 (Skip), or no treatment as a control (Non). Based on the analysis of plant development index, all plants with selected treatments grew more vigorous and vegetative in similar growth patterns. The discard treatment exhibited the best root-zone temperature control among the treatments. The discard treatment also resulted in the best root growth and above-ground growth, followed by skip, Insulate and Non. The total yields were obtained by the order of Insulate, Discard, Non and Skip. However the marketable yield was obtained by the order of Discard, Insulate, Skip and Non. The net incomes treated with Discard and Insulate were 9,687,600 and 9,396,000 Korean won per hectare, respectively, exhibiting higher incomes than that of Non. Therefore, it was concluded that insulation of the irrigation pipe and discarding nutrient solution inside the pipe before each irrigation were the most desirable and economical methods in terms of costs and yields.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.139-146
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• 2004

Kenaf (Hibiscus cannabinus L.), an annual plant of the family Malvaceae, is considered to be the most promising for alternative plants with potential use as a non-wood fiber source. The objectives of this study were to select the optimum seeding date and adaptable cultivar among newly introduced kenaf cultivars (Everglades-41, Tainung-2 and Chingpi-3) in Jeju island, and to clarify the photosynthetic characteristics of those cultivars. Among the three cultivars, the fresh shoot weight per unit area of Chingpi-3 at harvest season showed highest through all seeding dates, that of while Everglades-41 was the lowest. The difference of shoot yield at harvest mainly due to seedling stand rate and plant number per unit area among the cultivars. The Chingpi-3 showed the highest shoot fresh weight in the seeding date of May 11 and decreased trend in the late seeding dates. Net photosynthesis rate was higher on Everglades-41 with entire type leaf than other two cultivars with palmate type leaf. The activity of ribulose-1,5-bisphosphate carboxylase/foxygenase (rubisco) estimated from the A-Ci curve showed highest in Chingpi-3 among three cultivars. These results suggest that Chingpi-3 might be adaptable cultivar with seeding date of around May 10 for kenaf production in Jeiu island.

• Korean Journal of Medicinal Crop Science
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• v.16 no.6
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• pp.434-438
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• 2008

To selection of optimal shading material, two-year-old ginseng (Panax ginseng C. A. Meyer) of new cultivar, 'Cheonpoong' (CP), and native species 'Hwangsookjong' (HS) were cultured under three kinds of shading materials such as three-layered blue and a one-layered black PE (polyethylene) net (TBSB), blue PE sheet (BS), and aluminium coated PE sheet (AS) in imperfectly drained paddy soil. Growth characteristics, yield and ginsenoside contents were investigated under three shading materials. Yield and ginsenoside contents of ginseng were distinctly affected by intensity and quality of sunlight penetrated through shading materials. Light transmission ratio, air and soil temperature according to shading materials were higher in order of BS, AS, and TBSB. However, ratio of aerial phase and porosity of the soil were higher in order of AS, BS, and TBSB, respectively. There was no significantly difference in the ratio of rusty colored root by shading materials. CP showed higher stem length, leaf area, and root weight than that of HS, while the former showed distinctly lower discolored leaf ratio than that the other. Eight kinds of ginsenosides content of CP were higher than that of HS in $Rg_1$, Re, Rf, $Rb_1$ and Rc except $Rg_2$, $Rb_2$, and $Rb_3$. Total ginsenoside contents of CP was distinctly higher than that of HS. Total ginsenoside contents as affected by shading materials was higher in order of BS, TBSB, and AS in CP, while TBSB, BS, and AS in HS.

• Journal of Korean Society of Forest Science
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• v.98 no.3
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• pp.247-254
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• 2009

In this study, linear programming was applied to a case study in Gwangreung Experimental Forest of Korea Forest Research Institute investigating the effect of the desired future conditions on forest management. Considering the social, economic and ecological demands of people from the forest, the forest functions were classified into four including natural conservation, timber production, water yield and scenic conservation. The forest land areas were divided into four-types of forest functional zones and forest management prescriptions including the desired future conditions by the forest function type were established. The Model II linear programming was used in optimizing the forest management planning. The model includes management policies, as the constraints, for non-declining yield, allowable cutting area, allowable % age class distribution and allowable % species allocation as well as the land and other accounting regimes. Maximization of timber production was used the objective function. Based on the Model II formulations, the effects of the desired future conditions by the forest function type on forest management planning were investigated in terms of timber production, net present value and stand structures over time.

• Korean Journal of Agricultural Science
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• v.6 no.1
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• pp.33-44
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• 1979

These studies were carried out to investigate the effects of liver-fluke infection on the reproductive disorder and milk and meat production in Korean Native Goat. A survey of infected goat in Chungnam district was conducted with 474 head by interdermal reaction and also a clinical observation was founded. A experiment was carried out to determine the effects of liver fluke extract on the reproductive disorder by subcutaneous injection and milk and meat yield were measured from treat ed goats. The results obtained were summarized as follows. 1. The rate of positive goat was 71.3% among the surveyed goat and the highest rate was appeared at 3~4 years old goats as 81.4%. 2. The treated goats lost condition and failed to thrive, and became progressive weaker. 3. In hemogram, observation, the rate of eosinophil leucocyte was increased significantly by extract treated. 4. It was appeared the pathogenic signs such symptoms poisoning liver function disturbance and reproductive disorder from treated goats with liver fluke extract. 5. In milking goat the milk yield droped significantly and fattening goat did not fatten. 6. The gross income value per capita was lower from infected goat and it was analysed more sensitivly in net income value.

• Korean Journal of Medicinal Crop Science
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• v.8 no.4
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• pp.362-372
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• 2000

This study was conducted to obtain the basic information on the production of high yield and qualitied yam in Andong, major yam-producing district, in Kyongbuk province, using three major Yam cultivars, such as Danma, Jangma and Alata (round type). Alata showed the longest tuber width while Jangma showed the longest tube length. Danma showed the highest tube yield at 2,123 kg/10a. Tubes of Alata had higher dry ratio than those of other cultivars, suggesting that Alata could be used as good processing materials. Characteristics of top parts, such as vine length, leaf number, and lateral vine number showed typical sigmoid curves. Tuber characteristics such as length, width and fresh weight of tuber were linearly increased as the growth period was progressed. Relative growth rate (RGR) for new tuber and stem reached the highest value at 86 DAT (days after transplanting). There were similar tendencies among the cultivars in net assimilation rate (NAR). The highest crop growth rate (CGR) was appeared at 156 DAT regardless of cultivars. In the changes of leaf area ratio (LAR), there were significant differences among three cultivars. LAR were decreased at 86, 106 and 136 DAT for Alata, Danma and Jangma, respectively. However, specific leaf weight (SLW) was greatly increased at 176 DAT, and leaf area index (LAI) was decreased at 156 DAT in all cultivars.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.3
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• pp.212-219
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• 1985

The field experiment was conducted to study on the growth analysis of early variety, MTC-1, and late variety, Suweon 19, in response to seeding time at Suweon. The results summarized as follows: 1. Days required for Leaf-Formation(L-phase) of MTC-1 and Suweon 19 was same but that of Node-Thickening(N-phase) was quite different, e.g. late variety has two times longer. The period of Ear-Development (E-phase) in MTC-1 was 41 days and 53 days in Suweon 19. L-and N-phase were shortened by late seeding but E-phase was not influenced by seeding time. 2. Leaf Area Index(LAI) was decreased and Leaf Area Ratio(LAR) was increased by late seeding. Days required to maximum LAR was less by late seeding. Net Assimilation Rate(NAR) of L-, N-, and E-phase was decreased but its tendency in E-phase was remarkable at late seeding. 3. Crop Growth Rate(CGR) was increased gradually in the process of plant growth and it was the highest at Husk-stage. Relative Growth Rate(RGR) was increased in L-phase and was decreased in N- and E-phase, but its tendency in N-phase was great. 4. The period required to the maximum dry matter yield was shortened by late seeding and dry matter yield was increased by early seeding.

• Journal of agriculture & life science
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• v.45 no.4
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• pp.95-103
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• 2011

Ninety five Hanwoo steers averaging 226kg of body weight were used to investigate the effect of dietary type on feed efficiency, carcass characteristics and economical analysis in Hanwoo feeding over 22 months. Treatments were composed of commercial formula feed (formula feed), TMR and Fermented-TMR (F-TMR). Intakes of dry matter and TDN were greater in the F-TMR than the other treatments during each growing and fattening phase (p<0.05). Although daily body gain of the F-TMR was lowest during the growing phase, but was 48% greater than those of other treatment during the finishing phase (p<0.05). Feed efficiency of the F-TMR was maintained constantly during whole growing and fattening phases. Carcass weight and rib-eye area of the F-TMR were greatest (p<0.05) among treatments. However, meat yield index and the rate of grade A in meat yield were highest in the formula feed having the thinnest back fat. Marbling score was hugely (p<0.05) increased when steers fed F-TMR, and therateofgrade 1+andoverinmeatqualitywas96%intheF-TMR. Although feed cost in the F-TMR was increased by 40% compare to the formula feed, but net income was increased by 29% due to improvement of meat quality and body gain.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.311-318
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• 2022

Salicylic acid (SA), a phenolic compound, plays a pivotal role in regulating a wide range of physiological and metabolic processes in plants such as antioxidant cellular defense, photosynthesis, and biotic and abiotic stress responses during the growth and development. We examined the effect of exogenous SA application (100 mg·L^-1) on the growth, yield, photosynthetic characteristics, lipid peroxidation, and antioxidant enzyme activity of chili pepper plants under high temperature and drought stress conditions. SA treatment induced increases of net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) under the stress condition with the highest level after the third treatment. The contents of malondialdehyde and H₂O₂ were significantly lower in the third treatment of SA compared to the control. The activity of ascorbate peroxidase, catalase, peroxidase and superoxide dismutase, increased in treated plants by up to 247, 318, 55 and 54%, respectively compared to the nontreated control. There was no significant difference in the growth characteristics between SA-treated and nontreated plants, while the SA treatment increased marketable yield (kg/10a) by about 15% compared to the nontreated control. Taken together, these results suggest that foliar application of SA alleviates physiological damages caused by the combination of drought and heat stress, and enhances the photosynthetic capacity and antioxidant enzyme activities, thereby improving tolerance to a combination of water deficit and heat stress in chili pepper plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.40-47
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• 1987

Under the different conditions of planting density and compound fertilizer level, some agronomic and chemical characteristics of burley tobacco were investigated from 1982 to 1984. Leaf area and dry leaf weight per plant, crop growth rate, relative growth rate and net assimilation rate for 40-60 days after transplanting were higher with increasing plant spacing and fertilizer, but leaf area index was lower with increasing plant spacing. At topping stage, the leaf size was increased with increasing plant spacing and amount of fertilizer applied and the stem diameter was increased by increasing plant spacing. Leaf area, leaf weight per plant and weight per unit leaf area of harvested leaf were higher when plant spacing and fertilizer increased. It was estimated that the optimum plant spacing was 105cm x 34cm and level of com-pound fertilizer (N-P$_2$ O$\sub$5/ -K$_2$O =10-10-20) was 263kg/l0a for high yield. There were trends toward increase the contents of total alkaloid and total nitrogen with increasing plant spacing and fertilizer application. There was significant positive correlation between plant spacing and total nitrogen, and between fertilizer application and total nitrogen. The plant spacing of 105cm x 35 to 40cm and 227.5kg/l0a of fertilizer level may be profitable for farm economy and the low nitrogenous leaf.