• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.221-237
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• 2005

For developing the site-specific fertilizer management strategies of crop, it is essential to know the spatial variability of soil factors and to assess their influence on the variability of crop growth and yield. In 2002 and 2003 cropping seasons within-field spatial variability of rice growth and yield was examined in relation to spatial variation of soil properties in the· two paddy fields having each area of ca. $6,600m^2$ in Suwon, Korea. The fields were managed without fertilizer or with uniform application of N, P, and K fertilizer under direct-seeded and transplanted rice. Stable soil properties such as content of clay (Clay), total nitrogen (TN), organic mater (OM), silica (Si), cation exchange capacity (CEC), and rice growth and yield were measured in each grid of $10\times10m$. The two fields showed quite similar spatial variation in soil properties, showing the smallest coefficient of variation (CV) in Clay $(7.6\%)$ and the largest in Si $(21.4\%)$. The CV of plant growth parameters measured at panicle initiation (PIS) and heading stage (HD) ranged from 6 to $38\%$, and that of rice yield ranged from 11 to $21\%$. CEC, OM, TN, and available Si showed significant correlations with rice growth and yield. Multiple linear regression model with stepwise procedure selected independent variables of N fertilizer level, climate condition and soil properties, explaining as much as $76\%$ of yield variability, of which $21.6\%$ is ascribed to soil properties. Among the soil properties, the most important soil factors causing yield spatial variability was OM, followed by Si, TN, and CEC. Boundary line response of rice yield to soil properties was represented well by Mitcherich equation (negative exponential equation) that was used to quantify the influence of soil properties on rice yield, and then the Law of the Minimum was used to identify the soil limiting factor for each grid. This boundary line approach using five stable soil properties as limiting factor explained an average of about $50\%$ of the spatial yield variability. Although the determination coefficient was not very high, an advantage of the method was that it identified clearly which soil parameter was yield limiting factor and where it was distributed in the field.

• Computational Structural Engineering
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• v.23 no.3
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• pp.69-74
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• 2010

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.79-79
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• 2017

Grain Sorghum varieties grown in Korea have low productivity and are constrained by the fact that farmers' choice of improved varieties is limited. Hybrid cultivars have been demonstrated to be more productive and food security than pure line varieties. However, There's no available hybrid cultivars and never planted before in Korea. This study was, therefore, conducted to determine combining ability of Korean landrace varieties and cultivar, the level of heterosis of experimental hybrids depending on environments. Two cytoplasmic male-sterile lines were crossed with six male-fertile lines in accordance with North Carolina II mating scheme to generate 12 experimental hybrids. The hybrids were evaluated in replicated row-column alpha designs at two sites in Texas and South Korea under on-season production conditions. For each trait, general combining ability (GCA) and specific combining ability (SCA) effects were estimated using the line-tester method of analysis. Results indicated significant differences among genotypes for both grain yield potential and secondary traits. Hybrids were predominant for grain yield, and displayed up to 127% heterosis of A03017 ${\times}$ Sodamchal in Korea. Positive GCA for yield was observed for Donganme, Hwanggeumchal and Jungmo4002 in Korea. Among them Jungmo4002 and Donganme had highly positive for yield (227.90 and 84.90 kg ha-1), while it showed negative GCA for yield in College station (-40.90, -189.60 kg ha-1). ATx630 ${\times}$ Sodamchal had the greatest SCA for yield (468.10 kg/ha) in College station but at South Korea its SCA effect was -302.40 kg/ha. A similar trend was observed, followed by A03017 ${\times}$ Donganme (SCA effect = 215 kg ha-1 at College station vs. -44.20 kg ha-1 at South Korea). At South Korea the greatest positive SCA effect for grain was observed in ATx630 ${\times}$ Jungmo4002 as 322.20 kg/ha. Both GCA and SCA effects significantly interacted with site effects demonstrating the need for region adaptation of potential cultivars and test for developing Korea suitable cultivar.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.587-590
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• 2009

New onion hybrid cultivar, "Yeongpunghwang" was developed from cross between "MOS8", male sterile line and "Mokpo 11", pollen line by Mokpo Sub-Station, National Institute of Horticultural & Herbal Science, RDA in 2008. The crossing line was performed yield test in 2003. IT was evaluated as "Mokpo 11" in the regional yield trial test(RYT) from 2006 to 2008 during three years. This line is semi-erect plant growth type and has green leaf colour. It has broad ovate bulb shape and yellow skin colour in bulb characteristics. Plant height, leaf number, and bolting rate was 78cm, 7.9, and 3.9%, respectively. Lodging date as harvesting indicator was on 26 May. The yield potential of "Yeongpunghwang" was out-yielding 6% compare to check variety ("Sunpower") by with 8,344 kg/10a in RYT. It showed moderated cold hardness in all regional location which was conducting RYT, including Muan, Goheung, Changyeong and Andong. So this variety was recommend as a leading variety at southern area of korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.241-247
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• 2001

Boundary line method was adopted to analyze the relationships between rice yield and meteorological conditions during rice growing period. Boundary lines of yield responses to mean temperature($T_a$) and sunshine hour( $S_{h}$) and diurnal temperature range($T_r$) were well-fitted to hyperbolic functions of f($T_a$) =$$\beta$_{0t}$(1-EXP(-$$\beta$_{1t}$ $\times$ ($T_a$) ) and f( $S_{h}$)=$$\beta$_{0t}$((1-EXP($$\beta$_{1t}$$\times$ $S_{h}$)), to quadratic function of f($T_r$) =$\beta$$_{0r}$(1-($T_r$ 1r)$^2$), respectively. to take into account to, the sterility caused by low temperature during reproductive stage, cooling degree days [$T_c$ =$\Sigma$(20-$T_a$] for 30 days before heading were calculated. Boundary lines of yield responses to $T_c$ were fitted well to exponential function of f($T_c$) )=$\beta$$_{0c}$exp(-$$\beta$_{1c}$$\times$$T_c$ ). Excluding the constants of $\beta$$_{0s}$ from the boundary line functions, formed are the relative function values in the range of 0 to 1. And these were used as yield indices of the meteorological elements which indicate the degree of influence on rice yield. Assuming that the meteorological elements act multiplicatively and independently from each other, meteorological yield index (MIY) was calculated by the geometric mean of indices for each meteorological elements. MIY in each growth period showed good linear relationship with rice yield. The MIY's during 31 to 45 days after transplanting(DAT) in vegetative stage, during 30 to 16 days before heading (DBH) in reproductive stage and during 20 days after heading (DAH) in ripening stage showed greater explainablity for yield variation in each growth stage. MIY for the whole growth period was calculated by the following three methods of geometric mean of the indices for vegetative stage (MIVG), reproductive stage (HIRG) and ripening stage (HIRS). MI $Y_{I}$ was calculated by the geometric mean of meteorological indices showing the highest determination coefficient n each growth stage of rice. That is, (equation omitted) was calculated by the geometric mean of all the MIY's for all the growth periods devided into 15 to 20 days intervals from transplanting to 40 DAH. MI $Y_{III}$ was calculated by the geometric mean of MIY's for 45 days of vegetative stage (MIV $G_{0-45}$ ), 30 days of reproductive stage (MIR $G_{30-0}$) and 40 days of ripening stage (MIR $S_{0-40}$). MI $Y_{I}$, MI $Y_{II}$ and MI $Y_{III}$ showed good linear relationships with grain yield, the coefficients of determination being 0.651, 0.670 and 0.613, respectively.and 0.613, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.6
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• pp.475-483
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• 1990

An assessment of Kuwait's commercial fish stocks: hamoor (Epinephelus tauvina), zobaidy (Pampus argenteus), nakroor (Pomadasys argenteus) and sheiry (Lethrinus nebulosus), was conducted using length-frequency data, mean growth and mortality estimates obtained during 1981$\~$1988. The length-cohort analysis indicated that increases in fishing effort would not lead to long-term gains in yield of the stocks at the current estimate of natural mortality rate (M). At high M which was assumed arbitrarily, some benefit in yield could be obtained, especially for hamoor and sheiry. At low M, the yield of all stocks decreased with increased fishing effort. Increases in fishing effort resulted in significant dec-line in spawning stock size for all the stocks. Yield-per-recruit analysis indicated that, un-der low M assumption, a higher yield can be obtained for zobaidy and nakroor by reducing fishing effort. At moderate M, decreases in fishing effort brought gains in yield per recruit of the stocks, but it was not substantial compared with the present level of M. At high M, most of the stocks reached the maximum yield-per-recruit. Overall, increased fishing effort either will not be associated with large long-term gains in yield or, in some stocks, might cause a decline from the present level.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.11a
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• pp.115-121
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• 2002

The growth of semiconductor industry attracted to researchers like design, facility technique and making small size chip areas. But nowadays, cause of technology extension and oversupply and price down, yield improvement is the most important point on growth. This paper describes the computer mode]ing technique as the solutions to analyze the problem, to formalize the semiconductor manufacturing process and to build advanced manufacturing environments. The computer models are built referring an existing 8' wafer production line in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.1
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• pp.83-109
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• 1977

Isogenic lines for glabrous leaf (gl), hull color(gh) and glutinous endosperm (wx) were used to clarify the effects of the gl, gh and wx gene on the grain yield and yield components in rice plant. Eight genotypes: glgl ghgh wxwx, glgl ghgh WxWx, glgl GH-wxwx, glgl GH-WxWx, GL-ghgh wxwx, GL-ghgh WxWx, GL-GH-wxwx and GL-GH-WxWx were evalutated in the backcrossed $F_2$ generation. Significant effects were measured for gl genotypes on heading date, gh genotypes on grain fertility, and wxwx genotypes on number of panicles per hill and 1, 000 grain weight. The grain yield of straw hull and non glutinous lines were higher than gold hull and glutinous lines. The interaction of three genes, gl, gh and wx was significant for heading date, but not significant in other characters. The average value of isogenic lines which were combined with two recessive genes and one dominant gene were lower and the C.V. value was higher than the isogenic lines which were combined with two dominant genes and one recessive gene in all characters except plant height and number of grains per plant. The average value of isogenic line combined with three recessive genes was lower and the C.V. was higher than the isogenic line combined three dominant genes in all characters measured.

• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.11-20
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• 2004

This paper focused on square steel tubular column to H-beam connections (concrete filled tubular) with an outside-type diaphragm. Based on the yield line theory and the nonlinear static FEM analysis the specification equations were evaluated by comparing them with previous result of the simplified tensile experiment[please check. The yield line theory applied to the mechanical model theory revised by K. Morita, the nonlinear static FEM analysis using abaqus/standard, the ultimate strength equation in the specification equation using the factor for long-time loading, and the yield ratio according to material. The allowable strength in the specification equations applied the safety factors of 2.2 and 2.6 in the cases with and without filled concrete, respectively. Therefore, the evaluation of strength(for the previous result of the simplified tensile experiment in this study) was considered possible through the yield line theory, the nonlinear static FEM analysis, and the specification equations. Likewise, the specification equations were seen to be an underestimate of the previous result of the simplified tensile experiment. The strength and displaced mesh in the FEM analysis approximated the previous result of the simplified tensile experiment.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.302-307
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• 2004

When trains run over a snow-covered track at high speed, the snow accereted under car bodies may drop during train running. The dropped snow/ice lumps scatter the ballast on the track damaging the car body and the environment along the track in snowy regions. In this study, the snow-fall condition in winter around the Seoul-Busan high-speed line has been investigated to yield the countermeasure for the high-speed line. The climate near Japanese and French high-speed line as well as the relationship between the climate and countermeasure has also been investigated and the direction of countermeasure for Seoul-Busan high-speed line has been deduced. Consequently, the amount and frequency of snow-fall near Seoul-Busan high-speed line is less than that of Japan and France, so the speed restriction could be the fundamental countermeasure for Seoul-Busan high-speed line, and additional measure on rolling stock and infrastructure should be followed.