• Korean Journal of Poultry Science
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• v.46 no.3
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• pp.193-204
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• 2019

This study aimed to investigate the changes in production performance of five strains of Korean native chickens (KNCs), which have been collected and established at the National Institute of Animal Science, Korea, since 1992. A total of 38,026 KNCs were tested and survival rate, body weight, age at first egg-laying, hen-housed egg production, and egg weight was analyzed. The mean survival rates of KNCs were $87.9{\pm}0.8%$, but no significant difference in survival rate between strains and in the annual survival rates of KNCs was observed. The average body weight of KNCs was $1,609.7{\pm}21.3g$ at 150 d. The average body weight of KNC-Black was the highest, whereas KNC-White had the lowest weight. A gradual increase in the annual weight change has been observed in almost all strains after 2004. The average age at first egg-laying was $146.9{\pm}1.1d$ in KNCs where KNC-White was the earliest and KNC-Black was the latest. The age at first egg-laying has increased after 2003, but has gradually decreased after 2008. The average hen-housed egg production at 270 d was $77.3{\pm}1.7$ in KNCs, wherein KNC-Yellowish brown was the highest and KNC-Black was the lowest. The average egg weight at 270 d was $51.2{\pm}0.3g$ in KNCs, indicating that KNC-Black was the heaviest, whereas KNC-White was the lightest. A significant increase in annual egg weight has been observed since 2008. To conclude, the appearance and feather colors of KNCs have improved uniformly, and the body weight has also improved slightly since 2002.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.869-881
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• 2023

A genetic improvement program in Korea was implemented to improve the performance of Hanwoo cattle by generating livestock with genetically desirable economic characteristics. In particular, in response to external changes, such as the expansion of Free Trade Agreement (FTA), the livestock genetic improvement program has increased farm income by improving the productivity and quality of Hanwoo cattle. Using production cost data from Statistics Korea, the total input and output indices of Hanwoo feeding cattle from 2008 - 2021 were estimated and the growth and productivity changes were analyzed. The productivity change measures results were used to estimate the cumulative effects of the Hanwoo genetic improvement program on quality improvement, another purpose of the program, using a finite distributed lag model. The average annual increase in output (market weight) of Hanwoo was 0.9%. However, total input increased by 1.6%, resulting in a 0.6% decline in total factor productivity. In contrast, the Hanwoo genetic improvement program contributed significantly to the production of high quality beef, rather than contributing to improved productivity of the cattle. Hanwoo carcass weight, which is used as a performance indicator for the livestock genetic improvement program, has significantly improved and is projected to increase at a slower rate. The collective findings indicate the need for new performance indicators that can comprehensively indicate the performance of the genetic improvement of Hanwoo.

• New & Renewable Energy
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• v.5 no.4
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• pp.39-43
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• 2009

The variation of inflow at stream and hydrologic performance for small scale hydro power(SSHP) plants due to climate change have been studied. The model, which can predict flow duration characteristic of stream, was developed to analyze the variation of inflow caused from rainfall condition. And another model to predict hydrologic performance for SSHP plants is established. Monthly inflow data measured at Andong dam for 32 years were analyzed. The existing SSHP plant located in upstream of Andong dam was selected and analyzed hydrologic performance characteristics. The predicted results from the developed models show that the data were in good agreement with measured results of long term inflow at Andong dam and the existing SSHP plant. Inflow and ideal hydro power potential had increased greatly in recent years, however, these did not lead annual energy production increment of existing SSHP plant. As a results, it was found that the models represented in this study can be used to predict the primary design specifications and inflow of SSHP plants effectively.

• Korean Journal of Agricultural Science
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• v.49 no.2
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• pp.331-339
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• 2022

Deforestation and conservation of coniferous forest have been recognized as critical issues in Korea due to climate change. The main purpose of this research was to monitor changes of secondary metabolite contents and growth of Korean fir (Abies koreana) according to the temperature change in Mt. Halla. The Korean fir located at three different regions, Yeongsil, Witseoreum, and Jindallaebat, was monitored in April, July, and October from 2016 to 2018 and secondary metabolites, specifically lutein, α-carotenoid, and β-carotenoid, were analysed with high performance liquid chromatography. The results showed that average concentrations of lutein, α-carotenoid, and β-carotenoid were 0.82 - 23.30, 0.02 - 2.01, and 0.11 - 2.84 ㎍·g-1 and the highest concentration of secondary metabolite was observed in October compared to April and July. The average length and width of Korean fir in the three regions were 11.84 - 20.70 and 1.78 - 2.41 mm from 2016 - 2018. A correlation analysis showed that the concentrations of all three secondary metabolites were negatively correlated with temperature and a significant difference was observed between temperature and lutein concentration in Korean fir. Overall, growth and production of secondary metabolites in Korean fir highly depended on the temperature, and global warming thus might have an adverse effect on the growth and physiological changes of Korean fir in Mt. Halla.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.2
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• pp.108-115
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• 1991

A field experiment was conducted to evaluate the effects of cattle compost application on the change of soil physical properties and their relationship to yield performance of selected main forage crops. Maize(CV. Suweon 19) and sorghum hybrids(CV. Pioneer 9'31) as a summer crops and winter rye were grown on newly reclaimed red yellow soils(Fine loamy, Typic Hapludults) under different application rate of cattle compost associated with chemical NPK fertilization, from Oct. 1986 to Sept. 1989. Experimental field was laid down as a split plots design with four replications. The results obtained are summarized as follows: 1. Cattle compost application reclaimed soil physical propeties, such as formation of granular structure and water holding capacity, and it result in a great increase of plant growth and the rate of dry matter accumulation. 2. While cattle compost treatment reduced the portion of soild phase of the three phase constituents of soils, it increased the portion of air phase and liquid phase comparatively. 3. Organic matter, N, P, K, and mineral content in soil were markedly increased in the plot treated with compost. 4. Cattle compost application increased fodder production both in maize-rye and sorghum hybrids-rye cultivation. Annual dry matter yield of maize-rye cropping was 2183(NI'K only), 2425(NPK+compvst 3000 kg) and 2800kg/lOa(NPK + compost 6000kg/10a).

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.1
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• pp.11-18
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• 2012

Daily temperature data produced by harmonic analysis of monthly climate summary have been used as an input to plant phenology model. This study was carried out to evaluate the performance of the harmonic based daily temperature data in prediction of major phenological developments and to apply the results in improving decision support for agricultural production in relation to the climate change scenarios. Daily maximum and minimum temperature data for a climatological normal year (Jan. 1 to Dec. 31, 1971-2000) were produced by harmonic analysis of the monthly climate means for Seoul weather station. The data were used as inputs to a thermal time - based phenology model to predict dormancy, budburst, and flowering of Japanese cherry in Seoul. Daily temperature measurements at Seoul station from 1971 to 2000 were used to run the same model and the results were compared with the harmonic data case. Leaving no information on annual variation aside, the harmonic based simulation showed 25 days earlier release from endodormancy, 57 days longer period for maximum cold tolerance, delayed budburst and flowering by 14 and 13 days, respectively, compared with the simulation based on the observed data. As an alternative to the harmonic data, 30 years daily temperature data were generated by a stochastic process (SIMMETEO + WGEN) using climatic summary of Seoul station for 1971-2000. When these data were used to simulate major phenology of Japanese cherry for 30 years, deviations from the results using observed data were much less than the harmonic data case: 6 days earlier dormancy release, 10 days reduction in maximum cold tolerance period, only 3 and 2 days delay in budburst and flowering, respectively. Inter-annual variation in phenological developments was also in accordance with the observed data. If stochastically generated temperature data could be used in agroclimatic mapping and zoning, more reliable and practical aids will be available to climate change adaptation policy or decision makers.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.3
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• pp.351-357
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• 2011

An experiment was conducted to evaluate the effects of castration on growth performance, carcass characteristics, and meat quality of goat kids. Fourteen Boer-cross buck and wether goat kids (n = 7; initial body weight (BW) $38.0{\pm}0.35\;kg$ and $34.8{\pm}0.35\;kg$, for bucks and wethers, respectively) were grazed on annual Marshall ryegrass (Lolium multiflorum Lam.) for 56 days. Body weights were recorded after 4 h withdrawal from feed and water for two consecutive days, every 2 wk. After d 56, animals were harvested and hot carcass weight (HCW), cold carcass weight (CCW), dressing percent (DP), kidney and pelvic fat (KPF), longissimus muscle (LM) area, back fat (BF), and other carcass parameters were measured. Day 0 BW was used as a covariate for analyses. However, bucks were heavier than wethers at d 15 (p = 0.09), 42 (p = 0.001) and 56 (p = 0.001). Bucks had higher ADG (146 vs. 74 g/d; p = 0.001), HCW (21.2 vs. 18.8 kg; p = 0.06) and CCW (20.3 vs. 17.9 kg; p = 0.04) when compared with wether goats. Dressing percentage (51 vs. 47%; p = 0.06), KPF (0.44 vs. 0.16%; p = 0.02) and BF (0.41 vs. 0.21 cm; p = 0.05) were higher in wethers vs bucks, respectively; however, USDA live or carcass grades were similar. Longissimus muscle tissue from wethers and bucks were similar in darkness ($L^*$) and redness ($a^*$), but wethers had more (p = 0.02) yellow tint ($b^*$). Palmitic (C16:0), stearic (C18:0) and oleic (C18:1) acids were higher (p = 0.001) in muscle tissue from wethers compared to bucks. The saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) contents of muscle tissue were lower (p = 0.001) for bucks with no difference in polyunsaturated fatty acids (PUFA). Longissimus muscle initial temperature was higher in bucks (p<0.04) and pH change post-mortem was similar for bucks and wethers. These results indicated that castration of young market goats reduced growth performance and produced carcasses with more fat and higher SFA.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.143-150
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• 2012

A simulation methodology and corresponding program based on it is to be discussed for analyzing the effects of the networking operation of existing DHC system in connection with CHP system on-site. The practical simulation for arbitrary areas with various building compositions is carried out for the analysis of operational features in both systems, and the various aspects of thermal energy grids with connecting operation are highlighted through the detailed assessment of predicted results. The intrinsic operational features of CHP prime movers, gas engine, gas turbine etc., are effectively implemented by realizing the performance data, i.e. actual operation efficiency in the full and part loads range. For the sake of simplicity, a simple mathematical correlation model is proposed for simulating various aspects of change effectively on the existing DHC system side due to the connecting operation, instead of performing cycle simulations separately. The empirical correlations are developed using the hourly based annual operation data for a branch of the Korean District Heating Corporation (KDHC) and are implicit in relation between main operation parameters such as fuel consumption by use, heat and power production. In the simulation, a variety of system configurations are able to be considered according to any combination of the probable CHP prime-movers, absorption or turbo type cooling chillers of every kind and capacity. From the analysis of the thermal network operation simulations, it is found that the newly proposed methodology of mathematical correlation for modelling of the existing DHC system functions effectively in reflecting the operational variations due to thermal energy grids with connecting operation. The effects of intrinsic features of CHP prime-movers, e.g. the different ratio of heat and power production, various combinations of different types of chillers (i.e. absorption and turbo types) on the overall system operation are discussed in detail with the consideration of operation schemes and corresponding simulation algorithms.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.271-275
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• 2012

The average annual and winter ambient air temperatures in Korea have risen by $0.7^{\circ}C$ and $1.4^{\circ}C$, respectively, during the last 30 years. The continuous rise in temperature presents a challenge in growing certain horticultural crops. Chinese cabbage, one most important cool season crop, may well be used as a model to study the influence of climate change on plant growth, because it is more adversely affected by elevated temperatures than warm season crops. This study examined the influence of transplanting time, nitrogen fertilizer level and climate parameters, including air temperature and growing degree days (GDD), on the performance of a Chinese cabbage cultivar (Chunkwang) during the spring growing season to estimate crop yield under the unfavorable environmental conditions. The chinese cabbage plants were transplanted from Apr. 8 to May 13, 2011 when 3~4 leaves were occurred, at internals of 7 days and cultivated with 3 levels of nitrogen fertilization. The data from plants transplanted on Apr. 22 and 29, 2012 were used for the prediction of yield as affected by planting date and nitrogen fertilization for spring production. In our study, plant dry weight was higher when the seedlings were transplanted on 15th (168 g) than on 22nd (139 g) of April. There was no significant difference in the yield when plants were grown with different levels of nitrogen fertilizer. The values of correlation coefficient ($R^2$) between GDD and number of leaves, and between GDD and dry weight of the above-ground plant parts were 0.9818 and 0.9584, respectively. Nitrogen fertilizer did not provide a good correlation with the plant growth. Results of this study suggest that the GDD values can be used as a good indicator in predicting the top biomass yield of Chinese cabbage.

• Horticultural Science & Technology
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• v.31 no.5
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• pp.531-537
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• 2013

The average annual and winter ambient air temperatures in Korea have risen by 0.7 and $1.4^{\circ}C$, respectively, during the last 30 years. Radish (Raphanus sativus), one of the most important cool season crops, may well be used as a model to study the influence of climatic change on plant growth, because it is more adversely affected by elevated temperatures than warm season crops. This study examined the influence of transplanting time, nitrogen fertilizer level, and climate parameters, including air temperature and growing degree days (GDD), on the performance of a radish cultivar 'Mansahyungtong' to estimate crop growth during the spring growing season. The radish seeds were sown from April 24 to May 22, 2012, at internals of 14 days and cultivated with 3 levels of nitrogen fertilization. The data from plants sown on April 24 and May 8, 2012 were used for the prediction of plant growth as affected by planting date and nitrogen fertilization for spring production. In our study, plant fresh weight was higher when the radish seeds were sown on $24^{th}$ of April than on $8^{th}$ and $22^{nd}$ of May. The growth model was described as a logarithmic function using GDD according to the nitrogen fertilization levels: for 0.5N, root dry matter = 84.66/(1+exp (-(GDD - 790.7)/122.3)) ($r^2$ = 0.92), for 1.0N, root dry matter = 100.6/(1 + exp (-(GDD - 824.8)/112.8)) ($r^2$ = 0.92), and for 2.0N, root dry matter = 117.7/(1+exp (-(GDD - 877.7)/148.5)) ($r^2$ = 0.94). Although the model slightly tended to overestimate the dry mass per plant, the estimated and observed root dry matter and top dry matter data showed a reasonable good fit with 1.12 ($R^2$ = 0.979) and 1.05 ($R^2$ = 0.991), respectively. Results of this study suggest that the GDD values can be used as a good indicator in predicting the root growth of radish.