• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.6
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• pp.522-527
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• 2004

Barley growing in paddy fields often suffers from wet-injury due to oxygen deficiency in rhizospere caused by excessive water in the soil. This study was conducted to investigate responsiveness of growth, development and anaerobic glycolysis enzymes to acute hypoxia in barley seedlings. Barley seedlings at the third leaf stage were subjected to hypoxia (1 ppm dissolved oxygen) by sparging the culture solution with nitrogen gas for up to seven days. Length and fresh weights of the shoot and root were affected little by hypoxia for up to 5 days. But root dry weight was slightly decreased by hypoxia for 7 days. In the root, alcohol dehydrogenase and lactate dehydrogenase activities increased drastically under hypoxia, reaching at their maximum levels in 3 to 5 days of hypoxia and decreasing slightly thereafter. However, the activities of both enzymes changed little in the shoot. Increases of their activities in the root were contributed by all the isozymes found in barley. These results suggest that barley seedlings first adapt to hypoxia by rapidly activating fermentative glycolysis to stabilize cellular pH and to increase energy production for the following morphological adaptative changes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.655-668
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• 1994

Conventional deodorization filters using soil and compost reach the capacity limitation of deodorization in short period, because its removal mechanism primarily depends on adsorption. Therefore, in this study the experiment was performed on the removal of ammonia which is a strong inorganic malodor, frequently emitted from night soil treatment plants and sewage treatment plants, by seeding activated sludges on the bio-peat containing higher organic contents, water conservation capacity, permeability and lower pressure drop. As a result, in raw peat filter natural ammonia outlet was observed in consequence of pH increase resulted from ammonia ionizing in liquid phase. Ammonia removal mechanism primarily depended on the adsorption onto the anion colloidal substances in peat. In peat bio-filter, theoretical ammonium salts ratio was higher than that of raw peat, resulted from slight pH increase by microorganism activity, however, the experimetal value of ammonia-nitrogen accumulated in bio-peat was lower than that of raw peat because of nitrification by nitrifying bacteria. In the initial reaction period, adsorption was predominant in the ammonia removal mechanism, but nitrification was conspicuous after the middle period. Mass balance of nitrogen was established using experimental data of input $NH_3$ loading, output $NH_3$ loading, $NH_4{^+}$-N, $NO_x$-N, and Org-N. The critical time of unsteady state, which is the maximum activating point of microorganism in bio-filter, was determined using experimental data, and the ammonia adsorption curve was computed using regression analysis. On the basis of the results obtained by above analysis, the delay days for the saturation of adsoption capacity in peat bio-filter was calculated.

• Korean Journal of Animal Reproduction
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• v.11 no.3
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• pp.155-160
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• 1987

This study was carried out to determine the effects of cryoprotectants, freezing and thawing rates on the survival of 8-cell mouse embryos. The female ICR mice were induced to superovulated by intraperitoneal injections of 5 i.u. PMSG and 5 i.u. HCG given 48h apart and then were paired with males of the same strain. They were killed and embryos were flushed from the oviducts and uteri on 3 days after injection of HCG. Embryos were flushed with modified Dulbecco's phosphate buffered saline and equilibrated with 1.5M-dimethyl sulfoxide (DMSO) or 1.5M-glycerol by 3-step procedure. The freezing rates of the embryos were 1$^{\circ}C$/min from room temperature to -5$^{\circ}C$ and the embryos were seeded at -5$^{\circ}C$. After being held for 3 min at the seeding temperature, the rates were 0.3$^{\circ}C$/min from -5$^{\circ}C$ to -35$^{\circ}C$. From -35$^{\circ}C$ to -7$0^{\circ}C$, the rates were divided into 0.1$^{\circ}C$/min, 1$^{\circ}C$/min and 1$0^{\circ}C$/min, respectively. After being held for 5 min at -7$0^{\circ}C$, the embryos were plunged directly into liquid nitrogen. The embryos were thawed at 4$^{\circ}C$/min and 12$^{\circ}C$/min from -196$^{\circ}C$ to 37$^{\circ}C$, and for 2 min in 37$^{\circ}C$ water bath, respectively. The average number of ovulation points and embryos recovered were 42.7 and 34 appearing 79.5% recovery rate. Eight cell embryos in the embryos recovered were 26.3. The survival rates of embryos according to the freezing rates in the presence of 1.5M-DMSO were 73.5~80.6% at 0.1$^{\circ}C$/min, 75.0~79.5% at 1$^{\circ}C$/min and 52.8~54.7% at 1$0^{\circ}C$/min, but in the presence of 1.5M-glycerol were 62.9~67.6% at 0.1$^{\circ}C$/min, 61.4~68.3% at 1$^{\circ}C$/min and 25.5~30.2% at 1$0^{\circ}C$/min. The survival rates of embryos were not affected by the thawing rates.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1996.05a
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• pp.91-115
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• 1996

In the recent years, protected horticultural facilities have been modernized and glasshouses are also propagating in Korea, even most vegetables production are conducted in the traditional plastic houses covered with, for example, PVC film for just temperature keeping. It would limit the productivity and competitivity of the vegetable production industry without automatization and high quality year round production. A plant factory, aimed to produce vegetables in the limited areas, was initiated in Christensen farm, Denmark in 1957, and widely propagated in some developed countries. As it has the automatized system which enables to keep optimized environment conditions, it will be the best facility for high quality products as well as year round planned production. However, we have not even started the plant factory production. Since the plant factory is requiring lots of resources, besides plant cultivation technologies, such as environment control, automatic engineering and robotics, our approach to the development of plant factories should be minded on Practical Plant Factories considering our current farming practices and least capital needs rather than blindly employing the advanced technologies from developed countries. Thus, Korean plant factory development can be initiated with year round leaf vegetables production in NFT or DFT cultivation system instead of the moval bed system, in which aerial environment factors such as light, temperature, humidity and CO$_2$ concentration and root environment ones such as solution concentration, temperature, pH and water soluble oxygen shall be automatically controlled. And the seeding, seedling and transplanting operations shall be accomplished in the house entrance, and the harvesting and grading opreations shall be conducted in the house exit. For practical plant factories, environment control technologies including artificial light source, illumination and air conditioning, automatic management for nutrient solution and automatic production line of moval bed system, transplanting and harvest should be developed along with researches on the cost reduction of factory building construction.

• Korean Journal of Agricultural Science
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• v.42 no.1
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• pp.15-22
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• 2015

This study was conducted to evaluate the phytotoxicity of imazosulfuron+fentrazamide mixture in rice field. It is recommended that safe herbicide application was obtained at 3 cm of transplanting depth and in sandy loam or loam soil type. In the direct water seeding of rice, imazosulfuron+fentrazamide SC should be applied at least 10 days before sowing land ower than 25+100 g ai/ha. In case of imazosulfuron+fentrazamide SC application after sowing, If we use the herbicide 15 days after sowing, no herbicide symptoms will be detected even though the amounts of the herbicide increase. In the rice transplanting, it is recommended that imazosulfuron+fentrazamide GR is applied 5 days after transplanting. In case of sequential herbicide application, the imazosulfuron+fentrazamide SC application at 75+300 g ai/ha 15 or 20 days after transplanting after the application at 25+100 g ai/ha or 50+200 g ai/ha 3 days before sowing increases weed control efficacy and gives no phytotoxicity in the rice growth.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.764-772
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• 2018

It is necessary to explore the possibility of alternative habitats and research the characteristics of basic habitats due to seeding, culturing and harvesting of blood clams (Tegillarca granosa) in tidal flats. Currently, dependence on naturally occurring spat is much higher than in other species, which may lead to a reduction in biological resources. In this study, we selected a total of 5 sites (Changgi, Hopo in Cheonsu Bay and Dangsan, Sachang, Wangsan in Garolim Bay) and examined habitat suitability factors for suitable site selection. Also, we considered the relationship of habitat suitability factors (Environment: water content, organic content; survival: mud content, mean size; growth: chlorophyll a). As a result, Wangsan had the highest score of the main habitat of blood clams (Habitat suitability score, Wangsan: 87; Dangsan: 86; Sachang: 81; Hopo: 78; and Changgi: 73). The sediment in Garolim Bay was fine-grained and the seasonal variation was lower than Cheonsu Bay. Therefore, it is considered that Garolim Bay is more suitable as a potential area and easy to utilize the space. In the future, search and selection of potential suitable sites could be considered to solve problems caused by the reduction of biological resources and the production for blood clams.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.13-18
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• 1995

This experiment was carried out to investigate occurrence ecology and control of soil-flakes in flood-direct seeded rice field. The occurrence of soil-flakes were inhibited in blue light of 450nm wave length and promoted in red light of 660nm wave length. The diatoms of Pinnularia spp. largely occurred in low fertilizer level and which much more increased when nitrogen was mixed with thinly soil depth. The diatoms of Pinnularia spp. were effectively controlled by carbamate and triazine herbicides when treated in pre-emergence of soil-flakes. Beside, triazine herbicides, simetryne, dimethametryn, prometryne 5g ai/10a showed high control effect in pre and post-emergence of soil-flakes. Expecially, In water-direct seeded rice pyrazosulfuron-methyl molinate simetryne 5.37% GR and dimepiperate bensulfuron dimethametryn 7.643% GR showed high control effect on the soil-flakes when treated at 10 days after seeding and didn't showed rice injury.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.535-541
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• 1996

A seed pelleting technique was developed for easy handling of small tobacco seeds (variety, NC82) and for direct seeding in temperary planting bed or in field. The mixture of pelleting material, binder and seeds were moulded in cylindrical holes sized 2 mm diameter and 2 mm height in a plastic plate. Bentonite and cellulose powder were good materials to make pellets with CMC as binder, and bentonite formed the hardest pelleted seeds among the materials. The number of the pelleted seeds made with the same weight of the materials was different with materials used and the number of seeds contained in a pelleted seed could be controlled by mixture ratio of materials and seeds. The seedless pellets ranged 6.9 to 16.0% at the ratio of pelleting material and seed for 2~3 seeds in a pellet. The moisture absorption rate at 100% RH and $25^{\circ}C$ was greater in the order of clay < bentonite < cellulose. Germination rates of pelleted seeds with bentonite and cellulose were similar to that of usual seed, but it was significantly lower with clay pelleted seeds.

• Asian Journal of Turfgrass Science
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• v.18 no.1
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• pp.1-13
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• 2004

The growth characteristics of cool season turfgrass in the seaside landfill golf courses with the single-use of kentucky bluegrass and mixed-use with kentucky bluegrass and perennial ryegrass in the coast line are as follows. Water infiltration rate was higher in the kentucky bluegrass single-use groups recorded as 95.6∼125.9cm/hr than in the roups mixed with kentucky bluegrass and perennial ryegrass recorded as 180.3∼386.2cm/hr. The surface soil hardness and the soil penetration were ranged from 16.6 to 18.0mm and from 6.0 to 7.3kg/cm$^2$, respectively. The cultivar that showed the most excellent visual quality and visual color in the kentucky bluegrass single-use groups was Midnight(KB2), whose density around the root was relatively excellent, as well. North Star(KB3) known as highly resistant to salt was the secondarily excellent cultivar. Brilliant(KB1) had visual quality of about third grade, however, it seemed profitable to develop turfgrass ground by virtue of its high density. As of April 26, 2003, when 2 weeks had passed after seeding, the visual quality was better in the groups mixed with kentucky bluegrass and perennial rye grass than in the kentucky bluegrass single-use groups. The most excellent visual color was found in Midnight(KB2)+Brightstar SLT(PR2) among the groups mixed with kentucky bluegrass and perennial ryegrass. On August 4, 2003, a disease was found from one experimental group in Blackstone(KB4) and expanded into more than 50cm of diameter.

• Korean Journal of Weed Science
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• v.15 no.3
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• pp.175-182
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• 1995

The experiment was conducted to obtain basic information on weed ecology and effective weed control in direct-seeded rice Gelds at National Yeongnam Agricultural Experiment Station in 1994. Double cropping system of rice-barley reduced weed occurrence about 30% as compared with rice single cropping due to allelopathic effect of barley residue or stubble. Occurrences of red rice (weedy rice), barnyard grass and water foxtail were closely related with tillage method; the greatest occurred in no tillage plot followed by rotavation only and plow plus rotavation. Period of seed germination of barnyard grass and carbgrass varied with temperature and soil depth. In the same environmental condition, the germination period of barnyard grass shortened 3 to 5 days as compared with that of carbgrass. Two systematic applications of herbicides, that is, the first application at 10 to 15 days after seeding and the second at just after flooding, were the most recommendable system in dry-seeded rice field in terms of weed suppression and yield capacity.