• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.104-111
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• 2007

As protein content of milled rice, generally used as a benchmark for rice eating quality, is greatly affected by N fertilization and nutrition status of rice plant, understanding its response to nitrogen rate and plant nitrogen status at different growth stage is important for recommending N fertilizer management for high quality rice production. The responses of milled-rice protein content were compared and quantified under various combinations of basal+tillering and panicle N application levels in 2001 and 2002. Protein content of milled rice was ranged from 6 to 9%, increasing significantly with increasing basal+tillering and panicle N rates. However, milled rice protein content was raised much greater by panicle N than by basal+tillering N fertilization. Even though basal+tillering N increased up to 20 kg/ha, protein content of milled rice was observed less than 7% in case that panicle N was applied below 1.8 kg/10a. Regression analysis revealed that nitrogen accumulated until harvest was partitioned with almost constant rates of 58.3% and 46.5% to panicle and milled rice, respectively. The partitioning rates was slightly but not significantly different between experimental years. Protein content of milled rice showed linear and quadratic responses to the shoot N accumulation until panicle initiation stage (PIS) ant shoot nitrogen accumulation from PIS to harvest, respectively. The increment of milled-rice protein content per unit N increase was much greater in shoot N accumulation from PIS to harvest than in that until PIS. Regardless of shoot N accumulation until PIS upto 8 kg/10a, protein content of milled rice was lower than 7% and ranged from 6.5 to 7.5% in case that shoot N accumulation from PIS to harvest was below 3.0 kg/10a and below 6.0 kg/10a respectively. It would be concluded that even under the same N accumulation until harvest milled rice protein content could be different according to the N fertilizer management and weather condition especially during ripening, providing rooms for controlling protein content by N fertilizer management without damage to grain yield.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.4
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• pp.62-71
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• 2014

Three types of diffuser systems were manufactured and applied to investigate the effect of liquid fertilization of pig manure slurry by application of aeration processes. In the first type reactor, commonly used diffuser system, which diffuse air upward by diffusing aerator fixed at the bottom of the reactor is installed. In case of the second type, air diffuser is installed 10 cm above of the bottom of a reactor. In the third type reactor, the venturi-type air diffuser is installed at circulation pipe, which return pig slurry in the reactor(mixing-in-pipe process). The pig manure slurry separated to solid/liquid was flowed into the experimental reactor, and left as it for one week to precipitate solids. The concentration of organic matter, T-N, T-P and BOD in the raw pig manure slurry flowed into the reactor of bottom-fixed type aeration process were 1.82%, 4,400 mg/L, 360 mg/L and 13,542 mg/L, respectively. After aeration the concentration of organic matters, T-N, T-P and BOD in the slurry were 2.01%, 4,400 mg/L, 420 mg/L and 16,824 mg/L, respectively. The concentration of organic matter, T-N, T-P and BOD in the mixing-in-pipe type changed from 1.58%, 3,700 mg/L, 260 mg/L and 15,735 mg/L to 1.96%, 4,000 mg/L, 340 mg/L, and 18,098 mg/L, respectively. Changes of the concentration of organic matter, T-N, T-P and BOD of the pig manure slurry collected from the middle layers of two aeration reactors; bottom aeration process and the mixing-in-pipe process, were 10.4%, 0%, 16.7% and 24.2% and 24.0%, 8.1%, 30.8% and 15.0%, respectively. The thickness of foam layer generated on the surface of pig manure slurry in aeration tank was thinner in mixing-in-pipe reactor than bottom-fixed type aeration reactor.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.3
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• pp.131-137
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• 1986

Korean lawn, Zoysia japonica STEUD, is the type of a perennial warm-season lawn grass that has a naturally green period during 5 months from May to September. This study was carried out to detect the effects of N-P-K fertilization, regrowth capacity after mowing and chlorophyll contents on prolongation of the green period in Zoysia japonica grasslands. The results obtained are summarized as follows: 1. The effects of nitrogen fertilizer application on Zoysia japonica grasslands were affected on regrowth capacity after mowing, green color of leaf canopies and chlorophyll contents, respectively. 2. A the experimental plots which applied 45g/$m^2$/10 weeks of $N_3$ fertilizer, there were high significant effects on prolongation of the green period and the plots of phosphorus and potassium had additive effects. 3. Prolongation of the green period to the last ten days of October was obviously possible by slow degrees in proportion to increment of N-P-K fertilization. 4. However, it is interpreted that more prolongation of the green period is impossible with N-P-K fertilization and irrigation treatments, unless the intermediate turfgrasses between $C_3$ and $C_4$ plants must be found and bred.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.1
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• pp.41-48
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• 2010

Objectives: The aim of this study was to assess appropriate time to convert intramuscular progesterone support to oral administration for luteal phase support in in vitro fertilization (IVF). Methods: Seventy-six cycles of IVF in which fetal heart beat was identified after treatment were included. Patients underwent controlled ovarian hyperstimulation with GnRH agonist long protocol (n=7) or GnRH antagonist protocol (n=66). Cryopreserved embryo transfer was performed in three cycles. Luteal support was initiated by daily intramuscular injection of progesterone, and after confirmation of fetal heart beat, converted to oral micronized progesterone (Utrogestan, Laboratoires Besins International, France) 300 mg daily before or after 8 gestational weeks. The oral progesterone was continued for 11 weeks. Results: Overall clinical abortion rate was 3.9% (3/76) and mean time to conversion was $8^{+4}$ gestational weeks ($46{\pm}5.8$ days after oocytes retrieval). The abortion rate was 5.6% (1/17) and 3.4% (2/59) in patients with conversion before 7 weeks and after 8 weeks, respectively, which were not statistically significant (p=0.678). The miscarriages were occurred at $9^{+4}$ weeks, $11^{+3}$ weeks and $11^{+4}$ weeks. Conclusion: Sequential luteal support using intramuscular and oral progesterone yields a relatively low clinical abortion rate. If fetal heart beat confirmed, sequential regimen appears to be safe and convenient method to reduce patients' discomfort induced by multiple injections.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.1
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• pp.17-21
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• 2005

The effect of melatonin on in vitro embryo development and the expression of antioxidant enzyme gene in preimplantation porcine embryos was determined by modified semi-quantitative single cell RT-PCR. Porcine embryos derived from in vitro maturation /in vitro fertilization were cultured in 5% $CO_2$ and 20% $O_2$ at $37^{\circ}C$ in NCSU23 medium. Melatonin was added to medium at concentration of 1nM, 5 nM, and 10 nM. When treated with 1nM (39.0%) of melatonin, the developmental rate of embryos beyond the morula stage were higher than that of control group (31.0%) (p<0.05). Number of inner cell mass and tropectoderm cell in control (23.0${\pm}$0.5 and 17.3${\pm}$0.8), 1 nM (23.6${\pm}$0.6 and 19.0${\pm}$0.5), and 5 nM (23.3${\pm}$1.1 and 16.3${\pm}$0.8) treated with melatonin were higher than in 10 nM (20.0${\pm}$0.5 and 13.3${\pm}$0.8) treated with melatonin (p<0.05). To develop an mRNA phenotypic map for the expression of catalase, bax and caspase-3, single cell RT-PCR analysis were carried out in porcine IVM/IVF embryo. Catalase was detected in 0, 1 and 5 nM supplemented with melatonin, but bax and caspase-3 were detected in 10 nM treated with melatonin.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.2
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• pp.127-131
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• 2002

Critical nitrogen concentration (Nc), which is defined as the minimum % N in shoots required to maintain the maximum growth rate of top dry weight (W) at any time, was determined for rice plant. Using two rice varietal groups, japonica varieties and an indica $\times$ japonica "Dasanbyeo", 18 data points fulfilling the statistical criteria for determining Nc were obtained through eight N-fertilization experiments over two years at Suwon (37$^{\circ}$16'N), Korea. Nc dilution curve for each variety was obtained by fitting the Nc-W relationship to power function. However, The critical nitrogen curves for the two variety groups were not different statistically. Thus, a Nc dilution curve was fitted for the Nc data points pooled over the two variety groups and proposed in rice as: Nc=4.08, where W＜1.73 t h $a^{-1}$ , Nc=5.197 $W^{0.425}$3/ ($R^2$=0.964), where 1.73 t h $a^{-1}$ ＜W＜12 t h $a^{-l}$. The Nc for W＜1.73 t h $a^{-l}$ were estimated as a constant value of 4.08%, the mean value of the maximum N concentration for N-limiting condition and the minimum N concentration for N non-limiting condition. The model for Nc is applicable to diagnosing the nitrogen nutrition status during the rice growth period from emergence to heading stage. The Nc curve well discriminated the 144 data points between the N limiting and the N non-limiting groups regardless of varieties, cultural methods, and years.-limiting groups regardless of varieties, cultural methods, and years.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.140-146
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• 1999

This research was conducted to investigate the changes of $NH_4-N$ in soil, nitrogen uptake by rice plant, nitrogen-use efficiency and rice yield by the application of latex coated urea(LCU) on 10-day old seedling transplanted with machine on paddy field, Jeonbuk series at the Honam area, from 1997 to 1998. Almost all nitrogen in LCU application as basal dressing in whole layer was dissolved until maximum tiller stage, the maximum dissolution time was productive tiller stage and $NH_4-N$ content of conventional plot with surface application of fertilizer were lowered at full periods. Nitrogen deficiency symptom were appeared at heading stage of 31.6% SPAD value and nitrogen concentration was 1.29% shoot. From heading stage to ripening stage, the necessity of nitrogen-fertilizer was $2.9kg\;ha^{-1}$ for the conventional split application plot and $11.9kg\;ha^{-1}$ for the whole layer application plot of LCU basal dressing. Nitrogen-use efficiency was higher at the LCU application plot than the conventional application plot and was increased for 12.7% by fertilization at panicle forming stage. The additional fertilization at panicle forming stage to basal dressing of LCU causes 13% yield increase.

• The Korean Journal of Malacology
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• v.29 no.2
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• pp.105-111
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• 2013

The gonadal development of triploid and diploid Pacific abalones, Haliotis discus hannai was histologically investigated in spawning season. Diploid abalones had matured oocytes and spermatozoa, but most triploid had spermatocytes or developing oocytes that was slightly retarded in gonadal development compared to diploid abalones. In spawning experiment of triploid and diploid abalones, spawning rates of diploid male and female were 100%, but those of triploid female was 50% and male was 25% respectively. Investigation of spawned abalone eggs and spermatozoa revealed that length of diploid sperms head were 17.47 ${\mu}m$, breadth of head were 10.31 ${\mu}m$, length of spermatozoa were 130.72 ${\mu}m$, but those of triploid spermatozoa were 11.83 ${\mu}m$, 7.89 ${\mu}m$ and 103.36 ${\mu}m$ respectively. Triploid spermatozoa were significantly small to diploid spermatozoa (p < 0.05). The eggs of diploid and triploid were not different in size. The cross experiment between oocytes produced by triploids and spermatozoa by diploids ($3n{\times}2n$ cross) revealed that no fertilization were occurred, and $2n{\times}3n$ cross also revealed same result.

• Korean Journal of Plant Tissue Culture
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• v.22 no.6
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• pp.317-322
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• 1995

As a basic research for breeding new varieties, reciprocal -intergeneric crosses between Citrus junos and P.trifoliata were made. F$_1$ hybrid production using in vitro ovule culture, gametogenesis, and fertilization phenomena were investigated. Frequency of fruit set resulting from crossing of Citrus junos and Poncirus Trifoliata was 16.6% while that of Poncirus Trifoliata and Citrus junos was 11.7%. Callus formation occurred well when ovules at the 6th week after pollination were cultured on MT (Murashige and Tucker) medium supplemented with zeatin 0.5 mg/L and NAA 1.0 or 3.0 mg/L. Immature ovules developed into mature embryos of the MT medium supplemented with 2,4-D 0.1 or 3.0 mg/L. Immature ovules developed into mature embryos of the MT medium supplemented with 2,4 D 0.1 or 0.5 mg/L. The invitro germination rates of 20-week-old ovules set C. junos $\times$ P. Trifoliata and P. Trifoliata $\times$ C. junos were 54.5% and 48.6%, respectively. The emergence ratios of trifoliate hybrids obtained by C. junos $\times$ P. Trifoliata and P. Trifoliata $\times$ C. junos were 56.7% and 100%, respectively. The chromosome number of C. junos and P. Trifoliata was n = 9 or 2n = 18, and the sizes of their pollen grain were 33.75 $\mu$ and 25.0 $\mu$. The length and width of embryo sac in C. junos and P. Trifoliata were 69.38~79.23 $\mu$ and 27.50~38.56 $\mu$, and those of egg cells were 17.50~41.50 $\mu$ and 6.25~8.12$\mu$. Fertilization of C. junos and P. trifoliata terminated 72 h after pollination.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.308-312
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• 2012

BACKGROUND: The nutrient balance in Korea during 1985-2006 had continually increased and maintained the highest levels among OECD countries. The use of green manure crops such as barley and hairy vetch is common practice for reducing chemical fertilizer application and maintaining soil fertility. However, green manure crops can also be used as a livestock feeding material which may reduce nutrient balance in the national scale. We calculated nitrogen and phosphate balance under green manure-rice cultivating system where all green manure was removed and used for feeding livestock. METHODS AND RESULTS: The barley and hairy vetch grown in pure stands or in mixtures with different sowing rates were tested for rice cultivation without chemical fertilization. The conventional fertilization (NPK) for rice cultivation was selected to compare nutrient balance with green manure-rice cultivation. Nitrogen and phosphate balance were calculated according to the surface balance method of the PARCOM guidelines. Total aboveground biomass of mixture (barley and hairy vetch) was higher compared to that of pure barley or hairy vetch. Among the mixture with barley and hairy vetch, the highest aboveground biomass was observed in B75H25 (barley 75%+hairy vetch 25%). The nitrogen and phosphate balance in the B75H25 mixture was-104 kg N/ha and-50.3 kg P/ha, respectively. CONCLUSION(S): The barley and hairy vetch mixture proved to be a very effective strategy for biomass production of green manure. The amount of nitrogen and phosphate fertilizer to be applied is estimated to be 104 kg N/ha and 50.3 kg P/ha in order to maintain soil fertility if all green manure and rice straw were removed from rice field for livestock feeding.