• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.73-78
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• 2000

This study was conducted for 2 years at Chinju region to establish suitable seeding rate and fertilizing levels of nitrogen, phosphorous and potassium in spring-sown Jinyangbori. Heading and maturing were delayed by increasing fertilizers, especially nitrogen. Number of spikes per were secured by much seeding and increased application of nitrogen. One thousand grain weight reduced with increasing fertilization at any seeding rate. Relatively high harvest indices were observed with 12-10-4 at 10kg. 10a$^{-l}$ seeds planted, followed by 6-10-8 at 15 kgㆍ 10a$^{-1}$, and 6-10-4kgㆍ 10a$^{-l}$ at 20kg ㆍ 10a$^{-l}$ of N-P-K fertilizing combinations, respectively. There was no distinct differences on yield for various seeding rates in spring-sown barley. When seeding rate increased up to 15kgㆍ10a$^{-1}$, the positive effect of fertilizers was recognized as the function of balanced-application. It was possible to recommend 10kgㆍ10a$^{-1}$ as seeding rate and 6-5-4(N-P-K)kgㆍ10a$^{-1}$ as fertilizing combination in spring-time seeding considering low input and sustainable agriculture. There was no significant difference of protein content in grain by seeding rate. Increase of nitrogen fertilizer enhanced protein content in grain.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.203-208
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• 2020

This study was carried out to clarify the larvae and juveniles of egg development and autonomous development of Hemibarbus longirostris from Korea, and to obtain basic data for species conservation and seed production. The shape of the egg was circular and sticky. The average size of the eggs was 2.01 mm (n=10). At 185 hours after fertilization, more than 50% of the total embryos were hatched. The newly hatched larvae had an average total length of 8.10 mm (n=5) and had egg yolk in the abdomen. At 3 days after hatching, the larvae absorbed all egg yolk was average total length 8.64 mm. On the 6 days after hatching, the caudal tip of the notochord started to curve upwards was average total length 10.9 mm. At 70 days after hatching, the average total length 37.9 mm. The number of fins was i 8-10 in dorsal fin, iii 7 in the anal fin, and ii 5 in the ventral fin.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.805-819
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• 2017

The study was carried out to develop a mathematical model for evaluating the effect of organic fertilizers in organic rice production systems. A function to simulate the nitrogen mineralization process in the paddy soil has been developed and integrated into ORYZA2000 crop growth model. Inorganic nitrogen in the soil was estimated by single exponential models, given temperature and C:N ratio of organic amendments. Data collected from the two-year field experiment were used to evaluate the performance of the model. The revised version of ORYZA2000 provided reasonable estimates of key variables for nitrogen dynamics and crop growth in the organic rice production systems. Coefficient of determination between the measured value and simulated value were 0.6613, 0.8938, and 0.8092, respectively for soil inorganic nitrogen, total dry matter production, and rice yield. This means that the model could be used to quantify nitrogen supplying capacity of organic fertilizers relative to chemical fertilizer. Nitrogen dynamics and rice growth simulated by the model would be useful information to make decision for organic fertilization in organic rice production systems.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.5
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• pp.740-744
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• 2002

The relationship of gonad weight and liver weight with body weight of six fish species viz; Catla catla, Labeo rohita, Cirrhina mrigala, Hypophthlamichthys molitrix, Ctenopharyngodon idella and Cyprinus carpio under the influence of artificial feed, broiler manure, buffalo manure, N:P:K (25:25:0) and a control pond were examined after a rearing period of one year. The positive relationship between gonad weight and body weight was significant which showed the dependence of gonadal development on body weight in all the six fish species. The currelation coefficients were higher in female fishes. However, the major carps had a much smaller proportional gonadal weight as compared with Chinese carps and a common carp due to their faster growth rate. The overall comparison of six fish species under different experimental treatments revealed that highest liver weight was observed for C. idella closely followed by C. carpio. The maximum correlation value was observed with H. molitrix under the broiler manure. The maximum Gonadosomatic Index (GSI) remained as 32.63 for C. carpio followed by C. idella. The maximum value for Hepatosomatic Index (HSI). remained 1.99 for C. idella followed by C. mrigala.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.1-3
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• 1999

This study was carried out to determine the effects on rice growth, yields and soil improvement under the different nitrogen levels in machine-transplanted rice after plowing at the fruiting stage of milk vetch. The fresh weight of milk vetch at plowing time was 20.95 ton/ha. In dry weight, T-N and C/N were 1.58%, 21.8%, respectively. Organic matter, total nitrogen and exchangeable calcium of soil after the experiment in the plot of milk vetch were higher than those before the experiment. Leaf area and dry weight of rice plants at heading date increased as nitrogen level increased. The number of panicle and spikelets per $\textrm{m}^2$were not different except for the 110 kg/ha nitrogen level plot with milk vetch. Brown rice yield ranged from 5.45 to 6.08 ton/ha, in creasing with increased nitrogen level. So the yield increased by 1% at 77 kg/ha nitrogen level, 7% at 110 kg/ha nitrogen level plot with milk vetch compared with conventional level (rice straw 5.4 ton/ha and nitrogen 110 kg/ha).

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.3
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• pp.31-38
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• 2010

Various fundamental and practical theories and technologies are needed for the development of Best Management Practices (BMPs) to manage the problems. The objectives of this paper was to investigate the effect of fertilizer and Non-point suource (NPS) pollution discharges from the field. The effect of fertilizer application was measured with respect to 10 % and 20 % slopes, respectively, using artificial rainfall simulator. The effect of fertilizer application on runoff was not significant because the effect of slope and rainfall intensity were overwhelmed. Runoff from 20 % plots was 21 % larger than that from 10 % plots. While groundwater discharge from 10 % plots was about 70 % larger than that from 20 % plots. It was concluded that runoff and groundwater discharge were largely affected by slope. T-N concentration in groundwater was much higher than that in runoff for both 10 % and 20 % plots. While T-P concentration in groundwater was lower than that in runoff. It explained that T-N moved well through soil pores without adsorption and other chemical reactions but T-P was well adsorbed on the surface of soil particles.

• Reproductive and Developmental Biology
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• v.29 no.4
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• pp.269-271
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• 2005

The freemartinism is the most frequent form of intersexuality found in cattle, and females of heterosexual twins become sterile. With increase of twinning rates due to transfer of multiple embryos derived from in vitro fertilization, it is of great economic value to establish early diagnosis of freemartins to remove infertile individuals from breeding stock. In the present study polymerase chain reaction (PCR) of two different Y-chromosome specific segments (BRY.l and AMX/Y) was performed to identify freemartins from twins and less common single born freemartins in Korean Native Cattle (KNC). Two male-specific sequences were amplified in all heterosexual twins tested (n=5). In addition, Y-specific PCR products were detectable in one of the single born females (n=4) with visible genital abnormalities. These results suggest that the sensitivity of PCR-based assay may be sufficient to detect freemartinism in single born females as well as female partners of heterosexual twins in KNC.

• Horticultural Science & Technology
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• v.16 no.4
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• pp.514-516
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• 1998

This study was conducted to observe the effects of urea foliar spray to replace soil fertilization on defoliation ratio, shoot growth and fruit setting in satsuma mandarin (Citrus unshiu Marc.). Twice foliar sprays of 1% urea after harvest increased N and chlorophyll contents in leaves, and decreased defoliation during the winter season. The growth of the ovary and spring shoot was stimulated by the twice 0.8% urea foliar spray around the time of bud emergence. In addition, the treatments increased the number of flowers and fruit setting, but didn't influence fruit quality.

• Journal of the Korean Society of Tobacco Science
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• v.19 no.1
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• pp.33-39
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• 1997

Recently the method of basal compound fertilizer (N : P : K = 18.2 : 9.8 : 35.0) Placement has been changed from banding to broadcasting in tobacco cultivation. The effects of the compound fertilizer placement, level of fertilizer and additional urea application on the agronomic characteristics, two chemical compositions and physical Properties of burley tobacco(Nicotiana tabacum L. cv. KB 108) were investigated at Chonju Experiment Station, Korea Ginseng and Tobacco Research Institute in 1995-1996. Six treatments consisted of (1) band (method of fertilizer Placement) + In kg/10a(compound fertilizer) + 0(additional urea applied), (2) broadcast+140+0, (3) broadcast+140+25, (4) band+180+0, (5) broadcast+180+0, and (6) broadcast +180+25. The additional urea was applied at hilling. No significant differences were detected between banding and broadcasting method of compound fertilizer Placement in field 9rowth, wield, organoleptic qualify(price Per kilogram), chemical composition and Physical properties of cured leaf, The increased compound fertilizer by 30%(40k/10a) or the additional urea application by 25kg per 10a produced slightly higher yield than the recommended amount of basal compound fertilizer without additional urea application did. It also increased the total alkaloid content of cured leaf. It is recommended that no more basal fertilizer above the recommended amount and no additional urea application are needed in burley tobacco fertilization, even though the method of basal fertilizer placement being chanced from banding to broadcasting. Key words : Nicotiana tabacum, fertilizer placement, additional urea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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• pp.124-132
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• 2023

This study aimed to cross between Korean and Japanese pure lines of Neopyropia strains to establish cross breeding technology and identify a superior variety that harbors the strength of both parents. Four crossing combinations were tried using three methods, resulting in 1,476 single conchocelis colonies. The three co-dominant Cleaved Amplified Polymorphic Sequence (CAPS) markers (EF-1α/Mse I, TOP2/Mse I, car A/ApaL I) were used to distinguish heterozygotic sporophytes and their maternal lines obtained from the inter and intraspecific cross-fertilization within the wild type of Neopyropia strains. Of the 1,476 colonies, 26.9% (218) were heterozygotes obtained from the nuclear CAPS markers. Their maternal line was clearly confirmed using organelle CAPS marker and chimeric thallus was obtained from crossing experiment of Japanese N. yezoensis (♀) and Korean N. yezoensis (♂). The use of CAPS markers improved the efficiency of crossbreeding by quickly screening heterozygotes and maternal lines in the conchocelis phase, which otherwise required pigmentation mutants as genetic markers.