• Applied Biological Chemistry
• /
• v.43 no.2
• /
• pp.116-123
• /
• 2000

A numerical model of three-dimensional soil water distribution for drip irrigation management under cropped conditions was developed using Richards equation in Cartesian coordinates. The model accounts for both seasonal and diurnal changes in evaporation and transpiration, and the growth of plant root and the shape of root zone. Solutions were numerically approximated using the Crank-Nicolson implicit finite difference technique on the block-centered grid system and the Gauss-Seidel elimination in tandem. The model was tested under several conditions to allow the flow rates and configurations of drip emitters vary. In general, simulation results agreed well with experimental results and were as follows. The velocity of soil-water flow decreased drastically with distance from the drip source, and the rate of expansion of the wetted zone decreased rapidly during irrigation. The wetting front of wetted zone from a surface drip emitter traveled farther in vertical direction than in horizontal direction. Under this experimental weather condition, water use efficiency of a drip-irrigated apple field was greatest for 4-drip-emitter system buried at 25 cm, resulting from 10% increase in transpiration but 20% reduction in soil evaporation compared to those for surface 1-drip emitter system. Soil moisture retention curve obtained using disk tension infiltrometer showed significant difference from the curve obtained with pressure plate extractor.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.17 no.1
• /
• pp.3627-3641
• /
• 1975

The Government is trying to increase total food grain yield to meet national self sufficiency by means of increasing unit yield as well as extending crop land, and this year he set the target of 321,000 hectare of forest to clear for cropping. This study was carried to investigate the most efficient method of clearing hillock by bulldozer, and successful method to develope yielding potential of newly cleared land in short term. Since the conventional land clearing method is just earth leveling and root removing neglecting top soil treatment, the growth of crop was poor and farmer tends not to care the land. The top-soil-furrowing method is applied through out this study, that is advantageous especially for the land having shallow top soil and low fertility like Korean forest. In this study, various operating method were tried to find out most efficient method separately in connection with the land slope less than 25 percent and over, and several fertilizing methods to develop yielding potential. The results are as follows; 1) For the natural land slope utilization method, applicable to the land having less than 25 percent slope, reverse operating was more efficient than using forward gear of bulldozer. The operating time was 3 hour 32 minutes and 36 seconds using forward gear was 2 hour 32 minutes and 30 seconds for reverse gear operation per 1,000 square meter. 2) Bulldozer having angle blade adjustment needed 7hr 15min. for constructing of terrace per 10a compaire with the one having angle & tilt adjustment needed 6hr 4min for same operations. Specially there is significant difference for operation time of first period (earth cutting) such as bulldozer having angle blade adjustment needed 3hr 56min compaired with the one having angle & tilt adjustment 3hr 59min. In construction of terrace, the bull-dozer having tilting and angle blade adjustment was most suitable and performed efficiently. 3) For the fertilizer application treatment, the grass (Ladino clover) yield in first year was almost same as ordinary field's in the plot applied(N.P.K+lime+manure) while none fertilizer plot showed one tenth of it, and (N.P.K.+lime) applied plot yielded on third. 4) The effect of different land clearing method to yield showed significant difference between each treatment especially in the first year, and the conventional method was the lowest. In the second year, still conventional terracing plot yielded only half of ordinary field while the other plots showed as same as ordinary field's. 5) The downward top soil treatment plot showed most rapid improvement in soil structure during one year physio chemically, it showed increase in pH rate and organic composition, and the soil changed gradually from loam to sand-loam and the moisture content increased against the pF rate, and it gives good condition to grow hay due to the increase of field water capacity with higher available water content. 6) Since the soil of tested area was granite, the rate of soil errosion was increased about 2 to 5 percent influencing in soil structure more sand reducing clay content, and an optimum contour farming method should be prepared as a counter measure of errosion.

• Membrane Journal
• /
• v.18 no.3
• /
• pp.198-205
• /
• 2008

A novel technology for homogeneous deposition of zeolite particles on a porous support was developed so that those particles played a seeding role for the growth of zeolite crystals. After the particles were dispersed in water, the aqueous solution was 134 through the bore of a porous tubular support. By keeping the other side of the support in a vacuum, the aqueous solution passed through the pores of the support, leading the particles to be homogeneously deposited on the support. The amount of the deposited particles was investigated by changing the following operating parameters: a particle concentration in the solution, a time for deposition, and the feeding rate of the solution. The amount of the deposited particles increased from 0.0019 g to 0.0208 g as the concentration of the particles was changed from 0.01 wt% to 0.3 wt%, while the feeding rate and the deposition time were kept to 100 mL/min and 4 min, respectively. As the deposition time was varied from 1 min to 4 min, the deposition amount increased from 0.0004g to 0.0019g at the typical condition of the rest parameters. Also, it was observed that the deposited weight increased from 0.0029 g to 0.01 g as the feeding rate increased from 100 mL/min to 300 mL/min. However, the total permeance of water and ethanol decreased through the zeolite membrane as the deposited weight increased.

• Research in Plant Disease
• /
• v.8 no.1
• /
• pp.1-10
• /
• 2002

Climate in the year of 2001 could be summarized as severe drought from March to May, unusually high temperature in whole plant growth periods and clear weather condition especially in harvesting time of September and October without any typoons. In rice, major diseases such as leaf and panicle blast, bacterial blight, sheath blight and bacterial grain rot developed little due to unfavorable weather conditions, however, brown spot occurred severely due partly to the reduced use of N-fertilizer, Rice stripe virus infection was unusually high mainly in the west coast areas with four times more diseaseD area campared to the previous year, In pepper phytophthora blight was extremely severe in Cheonnam and Cheonbuk provinces, where had frequent rainfalls during growing period. Incidence of major diseases of tomato and cucumber in 2001 was relatively mild. In watermelon, penicillium fruit rot, one of the peculiar disease, spread over major production areas, whereas CGMMV, usually severe in every years was much reduced. Watermelon plants growing in open-fields were more severely diseased than those in plastic houses. Major diseases of chinese melon and strawberry occurred slightly and in particular, sudden wilt syndrome of chinese melon which was severe in 2000 showed mild infections in 2001. Incidence of white rot of garlic and onion was much lower unlike other years due mainly to spring drought and high temperature in the growing period. Infected area of potato bacterial wilt tended to increase in 2001 while fusarium wilt of sweetpotato was decreased. Apple diseases were generally mild, but powdery mildew of pear increased sharply. Barley scab was not severe as seen in other years.

• Korean Security Journal
• /
• no.17
• /
• pp.301-316
• /
• 2008

The occurrence of complicating, multilateral social condition demands the strategy for facing many social state and consolidating public security against criminal loss. The lacking ability of local police for preventing crime can't satisfy the demand of security and can't get rid of fear of crime. At last, it brings a distrust of public confidence and became a factor of serious social crisis. We have problems - not only making an alternative plan for preventing crime, but also introducing CPTED(Crime Prevention Through Environmental Design) by environmental design, to expect crime prevention and to select systemic crime prevention system and the most suitable model. And we have a goal - to recognize the importance of guard activity for local crime, analyse public safety activity in community & focusing guard activity as a strategy for them, apply CPTED in police and private security company as a local crime prevention & setting effective model, and, make it as an index for preventing & dealing with intellectual, brutal crime. The rapid growth in the guarding-activity field lighten the burden of police for crime-prevention. But the misjudgement of some people blocks it to be settled institutionally. It needs to reconsider what is the effective crime-prevention method, at this point of time when the all parts of a nation changing into unlimited competitive, private self-control system.

• Korean Journal of Soil Science and Fertilizer
• /
• v.14 no.4
• /
• pp.224-229
• /
• 1982

Effects of light intensity and temperature on photosynthesis and respiration of autogenous wild SUMBODY plants, Dystaenia takesimana, known as a prospective source of forage in Ulleung island, Korea, were investigated. Results were as follows : 1. Light saturation point at $20^{\circ}C$ was 34 to 38 klux and light compensation point was 4 to 6 klux. Apparent photosynthetic rate at light saturation was 9 to 12 mg $CO_2/dm^2/hr$. 2. Optimum temperature for photosynthesis was $20^{\circ}C$ and $Q_{10}$ values of two temperature ranges, 20 to $30^{\circ}C$ and 30 to $40^{\circ}C$, were 0.8 and 0.9 for photosynthesis, while $Q_{10}$ for respiration were 1.6 and 1.7. 3. Native plants sampled in area of higher altitude had a higher apparent photosynthtic rate at lower temperature and the plants sampled in area of mixed with bushes had lower a light compensation point. These rusults suggest that the Inland weather condition of Korea during spring and fall seasons might be. suitable for the SUMBODY growth but inadequate during summer.

• Journal of Veterinary Clinics
• /
• v.32 no.2
• /
• pp.191-195
• /
• 2015

A 7-year-old castrated male Korean Shorthair cat was referred with lethargy and anorexia. Laboratory examination revealed moderate degenerative changes of peripheral neutrophils on blood smear examination and decreased levels of free and total thyroxine ($T_4$) as well as bacterial growth on blood culture. Molecular analyses of the 16S ribosomal RNA gene and heat shock protein 60 gene confirmed the bacterium as Enterobacter cloacae. A minimal inhibitory concentration test showed multidrug resistance of the bacterium against 16 antibiotics. Polymerase chain reaction (PCR) and subsequent sequencing specifically for $bla_{TEM}$, $bla_{SHV}$, $bla_{CTX-M}$, and plasmid-mediated ampC genes revealed positive results to $bla_{TEM-1}$, $bla_{CTX-M-15}$, and plasmid-mediated $bla_{ACT-1}$ genes, indicating that the isolated bacterium contains plasmids containing genes encoding extended-spectrum beta-lactamase and plasmid-mediated ampC beta-lactamase. After 1 month of treatment with antibiotics and levothyroxine, the cat's condition improved; both the thyroid function test and the blood culture showed no abnormalities. This is the first report of community-acquired multidrug-resistant E. cloacae-induced euthyroid sick syndrome in a cat. By the prompt diagnostic procedures and properly selected antibiotic therapy, the cat was recovered from the multidrug-resistant bacterium-induced septicaemia.

• Korean Journal of Organic Agriculture
• /
• v.20 no.3
• /
• pp.357-368
• /
• 2012

This study was conducted to evaluate soil inorganic N concentrations and N uptake efficiency of sorghum ${\times}$ sudangrass hybrid (Sorghum bicolor (L.) Moench) as affected by organic nutrient sources from 2009 to 2011. The treatments included chemical fertilizer, compost, oilcake, alfalfa hay mulch, and control. Nutrient applications were made at rates equivalent to approximately 210 kg of actual N per hectare. The precipitation during the growth period from May to September was higher in 2011, followed by 2009, and 2010. Oilcake had the lowest C:N ratio in the raw materials. Compost treatment slowed N-mineralization rate in soil during the measured years. Soil mineral nutrition and dry matter production were not consistently affected by treatments, but the dry matter production was negatively correlated with the amount of precipitation from May to September for three years. Chemical fertilizer treatment increased N efficiency in plants in the first two years, observing with lower N efficiency in plants treated with compost for 3 years. Increased precipitation from June to August improved N efficiency in sudangrass plants treated with compost but reduced the efficiency with the chemical fertilizer. Total dry matter production and N efficiency in plants were not affected by the C:N ratio of the raw materials rather than weather condition.

• Korean Journal of Medicinal Crop Science
• /
• v.11 no.2
• /
• pp.161-166
• /
• 2003

Korean ginseng(Panax gmseng C.A. Meyer) is very difficult to obtain stable production of qualified ginseng roots because of variable stresses in soil environments. In environment stresses, soil condition is the most important factor, among which nutrients, especially inorganic materials such as N, P, K, Ca, Mg, Fe, etc., influence greatly on the ginseng growth. However, present ginseng field soils in Korea contain so much amount of such inorganic materials that a variety of remarkable disorders were noted in many ginseng plantations, resulting in decrease of qualitative ginseng production. Therefore, it is required to search for genetic resources and genes tolerant to salt stress for the development of ginseng cultivars. Selection of stress-tolerant ginseng lines in fields is very difficult because it is almost impossible to control properly the environmental conditions of soil. On the contrary, it can be studied with ease to search for stress-tolerant ginseng lines through in vitro culture because of easy manipulation of stress conditions. Murashige & Skoog(MS) media with 2.5 folds of $KNO_3,\;NH_4NO_3,\;MgSO_4\;7H_2O,\;KH_2PO_4,\;and\;CaCl_2\;2H_2O$ was established for the selection of ginseng lines tolerant to salt stress under the embryo culture.

• Korean Journal of Microbiology
• /
• v.40 no.4
• /
• pp.320-327
• /
• 2004

Three hundreds thirty two bacterial colonies which were able to degrade crude oil were isolated from soil sam­ples that were contaminated with oil in Daejeon area. Among them, one bacterial strain was selected for this study based on its higher oil degrading ability, and this selected bacterial strain was identified as Acinetobactor sp. B2 through physiological-biochemical tests and analysis of its 16S rRNA sequence. Acinetobactor sp. B2 was able to utilize various carbohydrates but did not utilize trehalose and mannitol as a sole carbon source. Acinetobactor sp. B2 showed a weak resistance to antibiotics such as kanamycin, streptomycin, tetracycline and spectinomycin, but showed a high resistance up to mg/ml unit to heavy metals such as Ba, Li, Mn, AI, Cr and Pb. The optimal growth temperature of Acinetobactor sp. B2 was $30^{\circ}C.$ The lipase produced by Acinetobactor sp. B2 was purified by ammonium sulfate precipitation, DEAE-Toyopearl 650M ion exchange chromatography and Sephadex gel filtration chromatography. Its molecular mass was about 60 kDa and condition for the optimal activity was observed at $40^{\circ}C$ and pH 10, respectively. The activation energy of lipase for the hydrolysis of p­nitrophenyl palmitate was 2.7 kcal/mol in the temperature range of 4 to $37^{\circ}C,$ and the enzyme was unstable at the temperature higher than $60^{\circ}C.$ The Michaelis constant $(K_m)\;and\;V_{max}$ for p-nitrophenyl palmitate were 21.8 uM and $270.3\;{\mu}M\;min^{-1}mg^{-1},$ respectively. This enzyme was strongly inhibited by 10 mM $Cd^{2+},\;Co^{2+},\;Fe^{2+},\;Hg^{2+},$ EDTA and 2-Mercaptoethalol.