• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.483-491
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• 2014

Double cropping system including paddy field soybean is widely adopted nationwide, due to rise in market price and its higher income than paddy field rice. Sowing date of soybean as a second crop is being delayed depending on first crop's growth period and harvesting time. Due to the increased temperature in October and delayed first frost date, soybean could be harvested without frost damage even in late-plating. Therefore, selection of soybean cultivar which is appropriate for this environment is very important. The effect of sowing date and genotype of soybean on growth and yield was investigated for three planting dates (June 20, July 5, and July 20) with ten cultivars developed for soy-pate production, to figure out plant development and yield pattern in delayed planting. As planting date is delayed, plant height and pod number was decreased and this pattern was more clearly detected in mid-late maturity cultivars. Hundred-seed weight did not show significant changes even in late planting, due to compensations between yield components. Yield reduction of July 20 in contrast to that of June 20 showed that Nampung (9.6%) showed the least yield decline. Maximum yield was achieved from Daepung, Taekwang, and Uram among other soybean cultivars in late planting. Shortening of growth period was strongly detected in reproductive stage while length of vegetative stage was regularly maintained in both early and mid-late maturity cultivars.

• Magazine of the Korean Society of Agricultural Engineers
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• v.14 no.2
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• pp.2634-2648
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• 1972

The aim of this Study is to bring Light on the effect of irrigation water temperature to the growth and harvest of Paddy rice in Various water Sources. 1. This research was completed in the writer's home nursery garden Located in Chungyoung-Ri, Hoeng sung-Myun, Hoengusung-Konn, Kangwan-Do. 2. The variety of Paddy rice was the IR667. 3. Practice was done by the treatment I .e river water, reservoir, tube well cold and tuke well warm with 3 riplications each. 4. The Paddy was transplanted in a pot 0.9 meter height and 1 meter Square without hottom filled with paddy soil to a planting depth 0.5 meter. The pot was laid underground and Covered with a film of polyethylene to keep of the rain. 5. The method of Cultivation was that used by the Filed Crops Experiment Station of the Office of Rural Development. 6. Atmospheric temperature was recorded every day of the growing period. The precipitation and Sun light was quoted by the KF-46 of Hoengsung. 7. The Soils in the test plots was relatively fortile, being Similar to ordinary paddy soils. 8. The charactor of irrigation water of surface and underground was both normal. 9. During the period of growth the average temperature of the underground water as $14.2^{\circ}C$ and that of the Surface was $24.1^{\circ}$. 10. The most useful water for the rice growing was that of river and reservoir while underground water was found to be generally injurious to the paddy growth because of low temperature. 11. In the case of underground water, there proved to be such harmful effects as reduction of culm length, rate of mature grain, panicle Length and grain weight and delay of tillering time, and heading time. Reading Therefore the writer conduded that the harvest of rice irrigated with underground water Showed a reduction of 15.8% compered with the rice irrigated by surface water.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.2
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• pp.98-104
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• 2010

Excess nitrogen (N) uptake of rice, which could cause much lodging, disease and reduction of rice quality, could be occurred at the paddy field with previous upland condition at which much soil N could be mineralized by soil-drying effect. N fertilizers of 0, 3, and 6 kg N $10a^{-1}$ were applied to early-maturity rice, cultivar Joanbyeo at the paddy field of first and second year after upland condition, and rice growth and nitrogen uptake were investigated to know the increase of rice N uptake at the paddy field with previous upland condition for one-year. Total dry matter (DM) and N uptake of rice at the paddy field with previous upland condition increased more than continuous paddy field. Total DM and N uptake of rice at the paddy field with previous upland condition increased linearly to N fertilizer 6 kg $10a^{-1}$ at the paddy field owing to vigorous growth compared to continuous paddy field. Rice N uptake was higher at the paddy field of the first year than the second year after upland condition in considering N uptake at the plot of no N fertilizer. Vigorous growth at the paddy field with previous upland condition resulted in higher rice yield which was related with high panicle and spikelet, but much N fertilizer as much as 6 kg $10a^{-1}$ at the paddy field with previous upland condition resulted in higher lodging and protein content of brown and milled rice. Particularly, protein content of brown and milled rice increased more when the same N fertilizer was applied two times splitly at transplanting and panicle initiation stage than when N fertilizer was applied one time at transplanting as basal N. N application with under 3 kg $10a^{-1}$ as only basal N was recommended at the paddy field with previous upland condition to obtain high quality rice without lodging.

• Korean Journal of Plant Tissue Culture
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• v.24 no.2
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• pp.77-81
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• 1997

For the early selection of heat-tolerant clones, the true potato seeds of 750 clones were obtained by several cross combinations : $CIP\;575015\;{\times}\;katahdin,\;CIP\;575015\;{\times}\;B6603-6,\;84\;I\;35-4\;{\times}\;katahdin,\;CIP\;575015\;{\times}\;NookSack,\;and\;CIP575015\;{\times}\;Superior.$ The ratios of in vitro tuberization at 3$0^{\circ}C$ were decreased by 43% in all cross combinations compared with at 2$0^{\circ}C$. In particular, tuberization rate of $CIP575015\;{\times}\;katahdin$ cross at 3$0^{\circ}C$ was only 21%. On the other hand, the rate of tuberization of $CIP575015\;{\times}B6603-6$ cross was 58 % at 3$0^{\circ}C$, so this cross combination was thought to be good heat-tolerant clone. To screen the heat-tolerant clones in lower land during high temperature period, microtubers were cultivated in Kangnung, and the characters of tubers and productivity were examined. Among screened clones, one clone at 2$0^{\circ}C$ and three clones at 3$0^{\circ}C$ were shown to be heat-tolerant. The yield of 89ML75-8 was 88% more than that of Superior, and dry weight rate of 89 ML64-11 was 18.8%. Therefore, 89ML64-11 clone was considered as a good cultivar for processing.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.1
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• pp.32-37
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• 1986

Field experiments were carried out to investigate the effect of wollastonite and iron refinery slag on the paddy rice yield insandyloam soil in which available silica level is 56 ppm. The results are as follows: 1. Application of wollastonite and iron refinery slag reduced the tillering and the height of rice plant in the early growth stage, while promoted those in the late growth stage. 2. As the same amounts of wollastonite and iron refinery slag were applied, the effectiveness on yield increase was same between the two silicate fertilizers. 3. The recovery ratio as measured by absorbed $SiO_2$ on rice plant over applied $SiO_2$, was greater in wollastonite than in iron refinery slag. 4. The increasing of the ratio of $SiO_2$ over N absorbed in rice plant trends toward decreasing the infection rate of neck blast. 5. The left-over ratio of available $SiO_2$ in soil over applied $SiO_2$, was greater in iron refinery slag than in wollastonite. 6. As measured by silica soluble in 0.5 N-HCl solution, 1 kg application per 10a of both silicate fertilizers increased about 2.3 ppm in soil silica content after harvest, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.151-158
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• 1993

Since the inhibition of floral induction was considered to be an important subject to get high yield of Angelica gigas, the effects of low temperature, daylengh and shading were investigated in this study. The yield of A. gigas root grown by inhibition of floral induction was compared with the yield obtained by traditional cultivation method. When the seedings were exposed to the natural low air temperature condition until late of November, the plants which had 6 to 8 leaves showed vernalizing effect, and when the low temperature treatment was prolonged until mid of January, 4 to 5 leaf plants showed vernalizing effect. But 2 to 3 leaf plants did not show vernalizing effect regardless of the length of chilling treatment. The effectiveness of exposure to low temperature was markedly dependent upon the age of plants. In the artificial low temperature treatment the range of temperature varied with plant age. Vernalizing effect at 1,5 and 9$^{\circ}C$ of temperature did not show 3,5,6 leaf plants, respectively. The bolting percent in 8 leaf plant at 1,5 and 9$^{\circ}C$ for 8 weeks decreased by 80,45 and 5%, respectively. As daylength became longer, the bolting percent of A. gigas was increased. plants which were grown in the full sunlight showed the highest value in bolting percent, and the bolting percent was not decreased significantly with changing from full sunlight to 50% shading. When A. gigas were grown by the inhibition of floral induction, dry root weight per l0a showed the greatest value in 3 year old plant which 3.6 and 2.4 times higher than that of 1 and 2 year old plant, respectively. The yield of root was increased by 73.7% in 2 year old plant and 159.6% in 3 year old plant compared with the yield obtained by traditional cultivation method.

• Korean journal of applied entomology
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• v.25 no.3 s.68
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• pp.169-173
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• 1986

Ginseng fields abolished by potato rot nematode (Ditylenchus destructor) (heavily infested with the nematode) were treated with selected nematicides after preplanting treatment with fumigants or non fumigant chemicals in the fall of 1982. Suppression of the nematode populations was noted in the fields fumigated by cylon (Cy) and treated with ethoprop (E) or triazophos (T). Also in these treatments, high percentages of shoot sprouting and low nematode damages were observed. In the fields fumigated by Cy, subsequent treatments with nonfumigant nematicides such as E, aldicarb (A), phenamiphos (Ph), oxamyl (O) and carbofuran (C) during cultivation had no effect on the significant decrease of the nematode, compared with Cy alone. No differences in shoot sprouting and symptom appearance were observed; however, survivalities of plants and root weights of 4-year old ginseng were high in A and E or E following preplanting treatment with E. Correlation coefficients of the nematode densities to host responses such as sprouting of shoots, symptom appearance, survivality of plants and weight of 4-year old ginseng roots were significant at and mostly before and after the time periods of survey.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.51-58
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• 2018

This study was a basic research for actual production of recycled aggregate concrete, and experiments were carried out on the change of water cement ratio and physical properties of recycled aggregate concrete with fixed slump. Results were as follows. Concrete using recycled aggregate were required increased water to maintain the target slump, and the recycled fine aggregate are necessary more increased water more than the recycled coarse aggregate. The replacement ratio of recycled fine aggregate be less than 60%, would be possible to obtain the air content volume that did not deviate from the concrete quality specification. The compressive strength of concrete using recycled aggregate decreased with increasing the replacement of recycled aggregate, and compressive strength decreased by 25% when 100% recycled fine aggregate were replaced. As a result of analyzing the correlation of compressive strength according to the mixing factors of concrete, it was found that replacement of recycled fine aggregate> water cement ratio> air content volume were influenced in order.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.637-640
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• 2008

In this study, the characteristics of strength development on high volume fly ash concrete(HVFAC)with Type 4 cement was experimentally investigated. Three levels of W/B were selected. Four levels of fly ash replacement ratios and two levels of silica fume replacement ratios were adopted. In the concrete mix, the water content of 125kg/m$^3$ was used, which is less than that of usual water content. As a result, it appeared that the compressive strength gradually decreased with increasing fly ash replacement ratio until 91days. However, regarding the compressive strength, the proper replacement ratio is about 20%, which is low compared to Type I cement case. It was observed that the tensile strength is proportional to the 0.72 power of the compressive strength. It appears that the prediction equation presented in Concrete Standard Specification overestimate the tensile strength in the low strength range, underestimate the tensile strength in the hi호 strength range.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.84-91
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• 2006

This study was carried out to comparatively evaluate growth characteristics of rice cultivars under rice-mono (conventional) and rice-Chinese milk vetch (Vetch) cropping system. Six rice cultivars such as Geumobyeo, Pungmibyeo, Hwayeongbyeo, Sobibyeo, Junambyeo and Dongjinbyeo were tested in 2005. The results obtained are summarized as follows ; plant height and culm length of all the tested cultivars at heading and harvest time were shorter in rice-vetch cropping system than conventional, however, nitrogen content of rice plants at heading and harvesting time was higher in rice-vetch cropping system. The total amount of nitrogen of rice plants was higher in conventional than rice-vetch cropping system. Nitrogen content of rice plant and uptake of Pungmibyeo was the highest of all the tested cultivars in both cropping systems. Generally, grain yietd ef tested cultivars seemed to be higher in conventional than rice-vetch cropping system. And it was the highest in Junambyeo as compared to those of other cultivars. Head rice ratio and protein content were higher in rice-vetch cropping system.