• Journal of The Korean Society of Grassland and Forage Science
• /
• v.9 no.2
• /
• pp.96-102
• /
• 1989

This field experiment was conducted to determine the effect of grazing and cutting management on the forage production and botanical composition at different legumes sown swards of the experimental field of Livestock Experiment Station. in Suweon, from Aug. 1985 to Oct. 1988. The results obtained are as follows: 1. Dry matter yield of cutting management (1213.0 kg/lOa) was higher by 19% than that of grazing management (1016.8 kg/lOa). Yield of pasture mixtures including alfalfa both cutting and grazing were higher than those including ladino clover and red clover. Yield under grazing was inferior to cutting in the first year but superior in the second year. 2. Seasonal dry matter production under grazing showed 5 1% in spring, 33% in summer and 16% in autumn, but under cutting showed 46% in spring, 42% in summer and 12% in autumn. 3. Daily dry matter production per 10a under grazing is decreased 5.9 kg in spring, 5.5 kg in summer and 3.7 kg in autumn. But under cutting is decreased 8.7 kg in summer, 6.6 kg in spring and 3.4 kg in autumn. 4. Botanical compositions of mixtures swards involving ladino clover and red clover were not influenced by method of defoliation. But mixtures swards including alfalfa were highly influenced by method of defoliation. Alfalfa ratio at the time of final utilization under grazing was about 30%, but under cutting was about 70-80%.

• Korean Journal of Plant Resources
• /
• v.33 no.6
• /
• pp.586-596
• /
• 2020

Chionanthus retusus has been used for landscaping and gardening trees, foods and medicines. This study was carried out to analyze the effect of fertilization on the growth performance of container seedlings (1-year-old) in C. retusus. We used multifeed 19 (MF) as a fertilizer, and measured the height, root collar diameter (RCD), biomass, seedling quality index (SQI) chlorophyll contents and chlorophyll fluorescence of the seedlings. The findings of this paper showed that the height, RCD, H/D ratio, T/R ratio and the fresh and dry weight of seedlings increased after fertilization. The moisture content of the stem and root did not show any significant difference among fertilizations, except in the case of the leaf. Production distribution such as the dry weight ratio of leaves and the stem dry weight ratio of fertilized seedlings had a higher value than that of non-treatment. SQI was the highest in MF 1,000 mg/L and 2,000 mg/L treatment. Chlorophyll contents (SPAD value) also increased with the increase in fertilization concentrations. Chlorophyll fluorescence (F_v/F_m) showed the highest value of 0.8 in MF 2,000 mg/L treatment.

• Journal of Korea Foresty Energy
• /
• v.2 no.2
• /
• pp.1-12
• /
• 1982

To study tile comparison of aboveground biomass of Pinus rigida Mill. of 18-year-old, plantations located in Whaseong, Yuseong and Wanju district were selected. Ten sample trees in each district selected taking account of DBH distribution were felled carefully to minimize loss of branches and stem analysed by 1m lag segment sectioned from base . The tree height and DBH were measured for sample trees in total growing within $200m^2$ experimental plot. The diagram of oven-dry weight distribution of stem, branch and needle for each 1m segment was constructed. The logarithmic regression equations between dry weight of each component and the two variables, $DBH^2$ and tree height, combined term were presented. The standing crops in the sample stand was estimated to be as much as 23.88, 54.09 and 42.68 tons of dry matter, above ground , per ha in Whaseong, Yuseong anf Wanju district respectively. Annual net production was estimated at 253,657 and 3.65 tons per ha per year respectively. The net assimilation rate was 1.65,1.95 and 1.81 kg/kg/yr in Whaseong, Yuseong and Wanju district respectively. The efficency of leaf to produce stem was 0.99, 1.12 and 1.30 kg/kg/yr respectively.

• Nuclear Engineering and Technology
• /
• v.50 no.2
• /
• pp.313-317
• /
• 2018

Licenses for the storage of spent nuclear fuel (SNF) and vitrified highly active waste in casks under dry conditions are limited to 40 years and have to be renewed for prolonged storage periods. If such a license renewal has to be expected since as in accordance with the new site selection procedure a final repository for spent fuel in Germany will not be available before the year 2050. For transport and possible unloading and loading in new casks for final storage, the integrity and the maintenance of the geometry of the cask's inventory is essential because the SNF rod cladding and the cladding of the vitrified highly active waste are stipulated as a barrier in the storage concept. For SNF, the cladding integrity is ensured currently by limiting the hoop stress and hoop strain as well as the maximum temperature to certain values for a 40-year storage period. For a prolonged storage period, other cladding degradation mechanisms such as inner and outer oxide layer formation, hydrogen pick up, irradiation damages in cladding material crystal structure, helium production from alpha decay, and long-term fission gas release may become leading effects driving degradation mechanisms that have to be discussed.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.40 no.5
• /
• pp.562-568
• /
• 1995

Changes in rice yield and soil chemistry of dry seeded rice in double cropping of rice and barley were investigated at National Yeongnam Agricultural Experiment Station during 5 years (1990-1994). Barley straw added or removed dry seeding had safe rice seedling stand for good rice production. However, the coefficient of variation of seedling stand by year was higher than dry seeding in rice single crop. Rice seedling height was slightly reduced by barley straw incorporation. However, it recovered soon as rice growing progressed. Heading time delayed 4 days in flat seeding method but not in high-ridged seeding method which imply that. this is more safe seeding technology than flat seeding method. Comparing to rice single crop, barley straw added dry seeding increased rice yield by 2∼19%(Average of 5 years: 8%) from second year due to higher panicle and spikelet number. Contents of organic matter was 2.71% in 1990. In 1994, it decreased 2.61% for rice single crop, while increased 3.02% and 3.41% for barley straw removed or added field, respectively. Rice grain quality was not significantly different among cropping patterns.

• Journal of environmental and Sanitary engineering
• /
• v.18 no.3 s.49
• /
• pp.64-68
• /
• 2003

Measurement of dried deposition for air pollutant was investigated in Gwang-ju Health college area for a year. The average value of air pollutants was investigated three times a month. Measured heavy metals and concentration of mass are not corelated. Heavy metals were thrown up air as state of large particles and they were moved by wind. Deposition of heavy metals and deposition velocities were high in the order of Fe > n > Cu > Pb > Cr and Pb > Fe > Cr > Zn > Cu, respectively. The pattems of deposition velocity of heavy metals for a year were much the same as each other except that Pb is faster than others.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2002.10a
• /
• pp.385-388
• /
• 2002

We investigated net outflow load and unit load of pollutants from a paddy fields area in dry year 2001. Amount of irrigation water in 2001 was about 61-63% of that in previous years 1999 and 2000 due to drought. The net outflow load and unit load of pollutants in 2001 were negative, showing that paddy fields acts as sink of pollutants due to function of water quality purification. The relationship between unit load of pollutants and net surface outflow (= surface outflow - irrigation water) showed positive correlation. The results showed that abatement of surface outflow by appropriate water management contribute to reduce surface outflow load from paddy fields.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.10 no.1
• /
• pp.1-14
• /
• 1973

In the Department of Naval Architecture, Seoul National University, the development of computer programs for the computer-aided ship design sponsored by the Ministry of Science and Technology has been begun. The project is to be accomplished as a four-year plan, and the results of the works of the first year, preliminary design of dry-cargo ships based on an optimization technique and some fundamental calculations accompanied with the basic design of ships such as calculations of displacement, hydrostatic characteristics of hull forms, stability, floodable length, load line and longitudinal section modulus, are given in the Report R-72-9[9] published by the sopnsor for the public interests. In this paper, the philosophy and methodological principles with which the preliminary design program given in Appendix II was developed are summerized.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2003.05a
• /
• pp.148-148
• /
• 2003

This study is to investigate the environmental levels and trend of dioxins, which was the 3$\^$rd/ year of environmental monitoring research for endocrine disrupting chemicals since 1999. Total 282 samples were analyzed from 115 sites including 26 sites of airs, 43 sites of waters, 11 sites of sediments and 35 sites of soil, which were the same as those of investigated sites in 2000. Sampling period was from June 2001 to June 2002. Target chemicals were seventeen species of 2,3,7,8-chlorine-substituted PCDD and PCDF congeners and were analyzed by the standard methods, established by National Institute Environmental Research (NIER). The average concentration of dioxins in air decreased from 0.324 pg-TEQ/N㎥ in 2000 to 0.287 pg-TEQ/N㎥ in 2001, and those in water and soil were 0.073pg-TEQ/L and 1.703pg-TEQ/dry g, respectively, which was the less values detected in 2000. In sediment, however, the value was 0.086pg-TEQ/dry g, which was the increase from the value of the year 2000. The concentration range of dioxins in air for 26 sites in 17 regions detected were 0.013∼l.664pg-TEQ/N㎥, 4 sites from those were exceeded the Air Quality Standards of Dioxin in Japan (0.6 pg-TEQ/N㎥). The tolerable daily intake of dioxins was calculated at the highest level (1.664) in air, with referring the soil and food data from Japan, was calculated to be 2.85pg-TEQ/kg/day, which was below the level of 4 pg-TEQ/kg/day suggested in KFDA(Korea). While the average concentration of dioxins in 15 big cities was 0.190 pg-TEQ/N㎥, that in 8 medium/small cities constituting an industrial complex was 0.558 pg-TEQ/N㎥. In water, the concentration range detected were 0∼0.946pg-TEQ/L and the trend of the average concentrations shows an increase from those of 1999 but decreased from those of 2000, any sites however were not exceeded the Water Quality Standards of Dioxin in Japan (1 pg- TEQ/L). In soil. the detected range were 0∼43.333 pg-TEQ/dry g and the average concentration decreased, compared with the results of 2000. According to the monitoring results by land utilization, the detected range were 0∼43.333pg-TEQ/dry g in farmland, 0.017∼0.601 pg-TEQ/dry g in the industrial area, 0.005∼0.049pg-TEQ/dry g in the park and 0.008∼1.825 pg-TEQ/dry g in the rest. In sediment, the detected range increased from 0∼0.244 pg-TEQ/dry g to 0∼0.537 pg-TEQ/dry g, based on the results of 2000. For the proper control of dioxins, continuous monitoring needs to be performed and in addition, the dioxin inventory should be prepared for major sources through the dioxin emission survey. These results would provide sound and solid basis for proper decision making of dioxins management like establishment of environmental quality standards in Korea.

• Korean Journal of Breeding Science
• /
• v.43 no.4
• /
• pp.330-336
• /
• 2011

A comparative study was conducted on genetic correlation between 12 open-pollinated families (32-year-old) and their one-year-old seedlings for early selection on the fast-growing trait in Pinus densiflora S. et Z.. Those twelve families were divided into three groups such as superior, intermediate, and inferior, on the base of the growth indexes of 32-year-old P. densiflora. The growth performance of the 32-year-old P. densiflora showed significant correlation with the growth traits of their one-year-old seedlings. Dry weights of the seedlings had significant correlation (P < 0.01) with the growth index of the adult plants and its $R^2$ value was 0.597, suggesting that 59.7% of the families could be selected by using dry weights of one-year-old seedlings. Furthermore, the growth rates of seedling heights for superior, intermediate, and inferior groups were 4.568, 3.773, and 3.535, respectively, resulting that seedlings of the superior group grew approximately 1.3-fold faster than those of the inferior group. Therefore, we concluded that two growth traits of one-year-old seedlings dry weight and growth rate were suppose to the early selection factors for the fast-growing trait for P. densiflora.