• Journal of Embryo Transfer
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• v.29 no.1
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• pp.13-19
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• 2014

This study was carried out to study the survival rate of thawed Hanwoo embryos frozen by the slow-rate freezing or the cryotop vitrification method. Hanwoo cumulus-oocyte complexes were recovered from ovaries at a slaughter house, matured for 20~22 hours, fertilized with Hanwoo semen for 5~6 hours, and cultured for 7~9 days in $38.5^{\circ}C$, 5% $CO_2$ incubator. For freezing, Day 7~9 blastocysts were collected. Embryos for the slow-rate freezing were equilibrated in 1.8 M ethylene glycol (EG) with Dulbecco's phosphate-buffered saline (D-PBS). Programmable cell freezer was precooled down to $-7^{\circ}C$, and the straw was seeded during 8 minutes-holding time, and was cooled to $-35^{\circ}C$ at the cooling rate of $0.3^{\circ}C/min$, and then was plunged and stored in liquid nitrogen. Embryos for the cryotop vitrification were treated in TCM199 with 0.5 M sucrose, 16% EG, 16% dimethylsulfoxide (DMSO). Embryos were then loaded individually onto cryotop and plunged directly into liquid nitrogen. The survival rates of embryos frozen by these two freezing methods were evaluated at 12 to 24h post-thawing. The survival rates of frozen/thawed Hanwoo embryos by the cryotop vitrification method ($56.86{\pm}26.53%$) were slightly higher than those by the slow-rate freezing method ($55.07{\pm}26.43%$) with no significant difference. Using the cryotop vitrification and the slow-rate freezing of Hanwoo blastocysts on Day 7 following in-vitro fertilization (IVF) treatment, the survival rates of frozen/thawed Hanwoo embryos were $72.65{\pm}18.3%$ and $79.06{\pm}17.8%$, respectively. The survival rates by the cryotop vitrification were higher than those by the slow-rate freezing on both Day 8 and 9 with significantly higher survival rate on Day 9 (p<0.05). Using the cryotop vitrification and the slow-rate freezing of Hanwoo embryos to compare between three different blastocyst stages, the survival rates of the blastocyst stage embryos were $66.22{\pm}18.8%$ and $45.76{\pm}12.8%$, respectively with higher survival rate by the vitrification method (p<0.05). And the survival rate of expanded blastocysts was higher than those of early blastocysts and blastocysts in two freezing methods with significantly higher survival rate by the slow-rate freezing method (p<0.05).

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.60-60
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• 2022

As various wheat variety for bread, all-purpose, and cake flour have been developed, suitable cultivation method for the end-use of the new variety need to be revised. This study was conducted to suggest an optimal nitrogen(N) fertilizer method for wheat Variety 'Saekeumgang' and 'Hojoong' with good noodle quality. In order to analyze the yield and quality changes of 'Saekeumgang' and 'Hojoong' as nitrogen fertilizer amount and timing, these varieties were sown on paddy soil in jeunju, Republic of Korea. The amount of N fertilizer was divided into 4 levels (7.1, 9.1 11.1,13.1kg/10a). In each levels, N amount in sowing date fixed as 3.6kg/10a, N amount in 10 days after heading(DAH) were treated 0 or 2kg/10a, and the other N amount was treated in regrowing stage. As N amount in regrowing stage increased, culm length of 'Saekkeumgang' was increased, but culm length of 'Hojoong' was not affected. Spike number/m² was increased when N fertilizer amount in regrowing stage increased as 3.5 to 7.5kg/10a. But, spike number/m² wasn't increased compared N amount 7.1kg/10a conditions when N fertilizer amount 9.1kg/10a. When the N fertilization amount in regrowing stage was increased by 1kg/10a, grain yield increased by 45.7 kg/10a in 'Saegeumgang' and 21.4kg/10a in 'Hojoong', so the fertilizer effect of 'Saegeumgang' was higher, when N fertilizer amount was increased to 2kg/10a at 10DAH, 1000-grain weight increased, but spike number/m2 and grain yield were not affected by N fertilizer at 10 DAH. Protein content and SDS-sedimentation value were increased as increasing N fertilizer amount in regrowing stage and 10 DAH. Among them, N fertilizer amount in 10 DAH had higher impact on protein content and SDS-sedimentation value. As N fertilize in 10 DAH, hardness of noodle was increased and chewiness of noodle was decreased

• Korean Journal of Soil Science and Fertilizer
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• v.1 no.1
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• pp.13-26
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• 1968

To establish the most efficient method of nitrogen and phosphorus fertilization in paddy rice a series of internationally coordinated research using $N^{15}\;P^{32}$ isotopes were carried out from the year 1962 through 1967, supervised by the Joint FAO/IAEA Division of Atomic Energy in Agriculture under the auspicies of FAO, UN. In Korea College of Agriculture, Seoul National University had been participated in the Coordinated Research Programme from the year 1963 through the last year, arid the results obtained through the six years' researches are summarized as follows: 1. In the application of superphosphate broadcasting or placement at the surface of paddy as basal dressing was most efficient. 2. Split or late application of superphosphate did not affect the grain yield of the rice, but its efficiency in the rice plant uptake was less than in the case of basal dressing of whole amounts. 3. The contents of available soil phoshorus of the experimental sites in Korea were above 60 ppm, and the efficiency of phosphorus utilization of the rice from the fertilizer was approximately 10 per cent. The grain yield response of the rice to phosphorus application in Korea was rather small comparing to those of other countries. 4. The nitrogen uptake of the rice plants from the fertilizer was most efficient when the fertilizer was applied at the time of ear prime growth. However, the most efficient utilization of nitrogen did not necessarily accompany the maximum yield of the rice and basic application of adequate amount of nitrogen was required to secure proper number of panicles. 5. In the application of nitrogenous fertilizer shallow placement at 5 cm depth was most efficient. The effect of split application of nitrogen was not so noticeable. It seemed due to the fact that total application amount of nitrogen, 60 kg N/ha, was smaller than that of usual dosage in Korea. 6. The efficiency of nitrogen utilization of the rice from the fertilizer was about 40 percent in Korea, and the yield reponse of the rice plant to nitrogen application was remarkable comparing to those of other countries, showing the marked differences in the fertilizer efficiency and grain yield according to the application method. 7. The nitrogen uptake of the rice plant was not likely affected by the time and the rate of phosphorus application whereas the efficiency of phosphorus utilization was affected to some degree by the method of nitrogen application.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.2
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• pp.124-130
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• 1986

To find out the optimum split application ratios of fertilizer nitrogen and potassium in the newly opened pasture at spring, a field experiment was conducted. Two levels of nitrogen and potassium application and three split application ratios of both fertilizer were treated by split design with 4 replications. The experiment was carried out from March, 1984 to October, 1985 on the experimental field of the Livestock Experiment Station in Suweon. The results obtained are summarized as follow: 1. Total DM yield was not showed signigicant difference among split application ratios of nitrogen and potassium. 2. DM yield of grasses was 4,854 kg/ha in heavy basal application of N and $K_2$O (160 kgN: 140 kg $K_2$O/ha), it was significantly increased by 16% than of conventional dressing (80 kg N: 70 kg $K_2$O/ha). But there was almost no difference in dry matter among N and $K_2$O split application ratios. 3. Dry matter yield of legume in heavy basal dressing was decreased by 23% than that of conventional dressing. In the methods of NK application, dry matter yield of legume was tended to decrease by 3% with equal application and 9% with heavy dressing in autumn, when compared with that of heavy dressing in spring. 4. There was no significant difference in dry matter yield of native species between different basic fertilization levels, but dry matter yield of native species was decreased by 6% with equal application and more increased by 11% with heavy dressing in autumn, when compared with the yield of heavy dressing in spring. 5. In aspect of the botanical composition, the percentage distribution of grasses was increased and the ratio of legume was greatly decreased by heavy dressing at basal fertilization. Also for good maintenance of botanical composition, it is suggested that the equal split application of N and $K_2$O was desirable.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.4
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• pp.270-275
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• 2013

Hairy vetch can fix nitrogen from the atmosphere as a leguminous cover crop. This research was carried out to determine optimum seeding method of hairy vetch and application effect in paddy. Field experiment was conducted at Sinheung series (fine loamy, mixed, nonacid, mesic family of Fluvaquentic Endoaquepts) from Sep. 2011 to Oct. 2012 at the National Institute of Crop Science (NICS), RDA, Suwon, Gyeonggi province, Korea. Hairy vetch used in the study was 'Cheongpyungbora', developed by National Institute of Crop Science. Seeding methods of hairy vetch consisted of Broadcasting Before Rice Harvesting (BBRH), Partial Tillage Seeding (PTS), Minimum Tillage Seeding (MTS), No Tillage Seeding (NTS), and Drill Seeding (DS). Both MTS and NTS showed the highest biomass among the seeding methods. The rice yield of MTS and NTS significantly increased compared to conventional fertilization (CF). Also soil properties including organic matter and bulk density were improved by incorporation of hairy vetch. Therefore, we suggested that MTS and NTS could be used to produce hairy vetch and rice in paddy.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.3
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• pp.165-181
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• 1976

Fertilizer(N,P,K) demand for crop production in 1980, 1990 and 2000 was estimated according to the two proposed models, one of which is fertilizer use efficiency model expressed in $Fn=(Y/E){\cdot}(1-Cs)Eu$, where Fn:fertilizer demand, Y:Crop production estimated, E:nutrient efficiency, Cs:fraction of natural resource nutrient in plant, Eu:fertilizer use efficiency and the other fertilization efficiency model expressed in Fn=Y(1-Cys)/Fe, where Cys:fraction of yield without fertilizer, Fe:fertilization efficiency. Total crop uptake of nutrient and its noncycling portion were estimated as criteria for fertilizer demand and nutrient maintenance. Total crop uptake of N,P,K was 600,000 M/T in 1965 700,000 M/T in 1974 and estimated to 880,000 M/T in 1980, 1,170,000 M/T in 1990 and 1,410,000 M/T in 2000. Fertilizer demand appeares to be about 90% of total crop uptake according to fertilizer use efficiency model and about 87% according to fertilization efficiency model. The noncycling nutrient was about 29% of total crop uptake. Fertilizer demand was almost same to the uptake amount in nitrogen, 1.5 times of uptake in phosphorus and half of uptake in potassium. Varietal development, improvement of soil fertility and cultivation method and development of fertilizer forms appears to decrease fertilizer demand by increasing efficiency term in two models while environmental stress such as low temperature appears to give reverse effect resulting in higher fertilizer demand. Fertilizer consumption in 1974 seemed to be unreasonably high especially in nitrogen and phosphorus and thus the effective use of fertilizer appeared as an urgent problem considering that large fields are still remained in lower fertility.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.2
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• pp.16-22
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• 2006

This study was carried out to estimate the physical and chemical soil characteristics in highway cutting slope areas. The soil was sampled in cutting area and natural vegetation area that was located in the upper areas of the highway cutting slope. The average total soil depth, bulk density, and soil hardness were bad in the highway cutting slope sites. The sandy loam was the most soil texture in the study area. The concentration of soil organic matter and nitrogen were very low in all highway cutting areas. The concentration of exchangeable cations was similar between the highway cutting slope and the natural vegetation sites in each highway. The soil pH was higher in highway cutting slope areas than in natural vegetation sites. In conclusion, chemical and physical properties of soil were bad in the cutting slope than in the natural vegetation area because of the loss of soil by cutting of slope area and less organic matter input by less vegetation in the highway cutting slope area. We should employ possible method to reduce the loss of soil, and compost and fertilization treatment could help to increase soil nutrient content in the cutting slope area.

• The Korean Journal of Ecology
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• v.21 no.5_3
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• pp.633-648
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• 1998

The forest vegetation of Mt. Nam Nature Park was investigated according to the phytosociological method. The vegetation in this study area was classified into 5 communities Quercus mongolica (Acer pseudo-sieboldianum subcommunity, Prunus sargentii subcommunity), P. sargentii, Pinus densiflora (Q. mongolica subcommunity, Stephanandra incisa subcommunity) and 5 afforestations Robinia pseudo-acacia, Populus tomentoglandulosa, P. koraiensis, P. rigida, Metasequoia glyptostroboides. Generally, were P. densiflora forest at the Southern slope and Q. mongolica forest at Northern slope dominant species from the top zone standing in Namsan tower. The dominance sequences on each stratum determined by the R-NCD (Relative net Contribution Degree) showed Q. mongolica and P. densiflora in tree-1 layer, Styrax japonica and Corbus alnifolia in tree-2 layer, S. incisa, S. japonica and rhododendron schlipenbachii in shrub layer, and Oplismenus undulatifolius, Eupatorium rugosum, Parthenocissus tricuspidata and Disporum smilacinum in herb layer. The soil was analyzed to investigate the soil conditions and fertility. The pHs of soil collected in each sites appeared strongly acidic with the range of 4.34 to 5.01 each community and especially, was the lowest value 4.34 in P. rigida afforestation. And Q. mongolica-P. sargentii subcommunity was distributed at the area with relative mesic conditions and high organic matters. Nitrogen was highest at P. sargentii community, phosphate at P. densiflora-S. incisa subcommunity, calcium, potasium and magnesium of exchangeble cation at R. pseudo-acacia afforestation. Especially, the level of calcium in R. pseudo-acacia afforestation, P. koraiensis afforestation and P. densiflora community was shown the highest (0.38-1.48 mg/100g) compared to other communities, because of the influence of lime fertilization used to improve acidic soil.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.8-14
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• 2015

Livestock waste compost tea is a liquid extract of compost obtained by mixing livestock compost. In this study, some chemical and microbiological characteristics of compost tea depending on the kind of raw materials used were examined, and several experiments to investigate the practical effects on Chinese cabbage cultivation were conducted. This experiment showed that livestock composts needed to be added into aerated water at the ratio between 1:100 and 1:10 (1 part compost to 10~100 parts water) to produce the high quality compost tea. Compost teas must be aerated more than 24 to 48 hours to be able to support aerobic organisms. In cultivation test with compost teas, swine manure compost teas were made by the extracting ratio of 50x, in the aerated condition for 24 hours in water and oil cake in the extracting ratio of 100x were added as supplements. Following the input of oil cake, the concentration of nitrogen and aerobic bacteria increased. Another experiment was conducted to determine the effect of different swine manure compost teas on plant growth and yield of Chinese cabbage. The fresh yield of Chinese cabbage was higher in the fertigated plots by compost tea with oil cake compared to those of N, $P_2O_5$, $K_2O$ fertilization plot with chemical fertilizer by soil test recommendation (Fert. NPK). The effect of compost tea on growth of Chinese cabbage was largely attributable to the increased number of microorganisms as well as nutrients.

• Animal Bioscience
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• v.36 no.10
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• pp.1530-1535
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• 2023

Objective: Semen cryopreservation result in decreased sperm parameters and fertilization ability. Sericin exhibits antioxidant activity by reducing lipid peroxidation resulting from free radicals, which can potentially improve cryopreservation outcomes. The present study aimed to examine the efficacy of various sericin concentrations supplemented with a rooster semen-freezing extender on post-thaw semen quality and fertilizing ability of sperm after cryopreservation. Methods: Semen samples were collected from 40 roosters (5 reps), then were pooled, and divided into four groups by the levels of sericin supplementation (0%, 0.25%, 0.50%, and 0.75%) in a freezing extender. Semen suspensions were loaded in medium straw (0.5 mL) and cryopreserved with the traditional liquid nitrogen vapor method. Post-thawed semen was evaluated for sperm motility, sperm viability, and lipid peroxidation. Also, the fertility test was determined. Results: The results showed that supplementation of the freezing extender with 0.50% to 0.75% sericin resulted in greater total motility and progressive motility and lower malondialdehyde levels than the other groups after cryopreservation (p<0.05). However, the viability of 0.75% decreased compared with the value of 0.50% sericin supplementation (p<0.05). Moreover, the fertility and hatchability of total eggs were significantly higher in the 0.50% sericin group than in the other groups (p<0.05). Conclusion: In conclusion, 0.50% sericin is recommended as an alternative component of the freezing extender to improve cryopreserved rooster semen.