• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.209-209
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• 2017

The application of liquid swine manure to soil has been commonly reported to increase crop productivity by improving plant nutrient availability. This study was conducted to investigate the effect of liquid swine manure (LSM) application on yield of green manure crops in paddy. Three different application rates of LSM equivalent to 25%, 50%, and 75% of standard fertilization rate of P were applied to the paddy field after rice harvest, and two cover crops, hairy vetch (Vicia villosa Roth) and barley (Hordeum vulgare L.), were subsequently mix-seeded and cultivated. Plant height of barley was 7% higher in LSM P25% and LSM P50% compared to control treatment (no LSM application), while no significant difference was observed between LSM P75% and control. However, there were no significant differences in plant height of hairy vetch among treatments. Dry matter (DM) yield of green manure increased with LSM application rate, reaching a maximum at LSM P50% (38 and 17% yield increase over control for hairy vetch and barley, respectively), but it decreased at LSM P75% rate. Nitrogen production by green manure crops was the highest in LSM P50% treatment, where the amount of produced N was 57% higher than the optimum N fertilization level for rice ($90kg\;N\;ha^{-1}$). Excess green manure biomass above an optimum level can be removed and utilized either for incorporation into nearby cropland or for sale as fresh forage. Therefore, it is concluded that the application rate of LSM P50% is recommendable for the maximum biomass and nitrogen production from green manure crops in paddy.

• Journal of Climate Change Research
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• v.8 no.4
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• pp.305-312
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• 2017

We aimed at investigating the difference in $N_2O$ emission factors of chemical and organic fertilizers and identifying the main factors influencing annual fluctuations in $N_2O$ emission. We conducted two-year experiments in 2016 and 2017 in an agricultural field planted with sweet potato (Ipomoea batatas). Treatments included chemical NPK fertilizer (NPK) and chicken compost application at $10\;ton\;ha^{-1}$, $20\;ton\;ha^{-1}$, and $30\;ton\;ha^{-1}$ rates (CK1, CK2 and CK3). Control was also employed with no addition. Results showed that $N_2O$ emission rates were significantly related with soil water status and soil available N contents. Significant correlation between % water filled pore space (WFPS) and $N_2O$ emission was observed only when the %WFPS was greater than 40% and during the initial stage of the experiment (<60 d). Comparison of the emission factors in 2016 and 2017 showed us that the emission factor was greater in 2016 when the %WFPS was maintained higher by 16.5% compared to that in 2017. In 2016, the emission factor of organic fertilizer was higher than that of chemical fertilizer, while in 2017, the pattern was reversed. Annual variability in $N_2O$ emission could also be originated from the available N contents remaining in soil after being taken up by plants. If we apply excessive N fertilizer, the soil would contain excess amount of N which was not uptaken by plants, leading to a huge increase in $N_2O$ emission. This case would overestimate emission factor, which was the case for the organic fertilizer in 2016. Over-fertilization should be avoided when we set up an experiment to determine $N_2O$ emission factor.

• Reproductive and Developmental Biology
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• v.39 no.4
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• pp.117-125
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• 2015

Iron is required for cell viability but is toxic in excess. While the iron-mediated malfunction of testicular cells is well appreciated, the underlying mechanism(s) of this effect and its relationship with fertility are poorly understood. Ferritin is a ubiquitous intracellular protein that controls iron storage, ferroxidase activity, immune response, and stress response in cells. Ferritin light chain protein (FTL) is the light subunit of the Ferritin. Previously, we had identified the FTL in bovine spermatozoa following capacitation. In present study, to investigate the role of Ferritin in sperm function, mice spermatozoa were incubated with multiple doses (1, 10 and $100{\mu}M$) of sodium nitroprusside (SNP), an iron donor. SNP was increased Ferritin levels in a dose-dependent manner. The Ferritin was detected on the acrosome in spermatozoa by immunocytochemistry. Short-term exposure of spermatozoa to SNP increased tyrosine phosphorylation and the acrosome reaction (AR). Finally, SNP affected a significant decrease in the rate of fertilization as well as blastocyst formation during early embryonic development. On the basis of these results, we propose that the effects of Ferritin on the AR may reduce overall sperm function leads to poor fertility in males and compromised embryonic development.

• Applied Biological Chemistry
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• v.25 no.3
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• pp.150-154
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• 1982

Top-dressing pot experiment with $^{15}N$ urea was carried out by using three varieties. Two-split application was much better for Tongil line than 4-split. Fertilization efficiency (Fe), use efficiency (Eu) and absorbed fertilizer nitrogen efficiency (Ef) were much greater in 2-split than in 4-split. The order of Fe followed that of Ef. Grain yield and $^{15}N$ excess % among plant parts suggest that Tonsil line uptakes fertilizer nitrogen much in early stage and retranslocated well later. The order of soil nitrogen increment in plant per fertilizer nitrogen in plant $({\Delta}Ns/Nf)$ might be an index of soil nitrogen use efficiency due to fertilizer.

• Journal of Ginseng Research
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• v.38 no.1
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• pp.73-77
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• 2014

Field and nutrient cultures of American ginseng (Panax quinquefolius L.) were used to establish foliar symptoms related to boron (B) concentration in leaves and soils, and to evaluate radish as a time-saving model system for B nutrition. Application of excess B, 8 kg/ha versus the recommended 1.5 kg/ha, to field plantings of 2-, 3-, and 4-yr-old American ginseng plants just prior to crop emergence caused, within 4 wk after crop emergence, leaf symptoms of chlorosis followed by necrosis starting at the tips and progressing along the margins. The B concentration in leaves of 2-4-yr-old plants receiving 1.5 kg/ha Bwas $30{\mu}g/g$ dry mass compared to $460{\mu}g/g$ dry mass where 8 kg/ha B was applied. Similarly, B concentration in soils receiving the lower B concentration was 1.8 mg/g dry mass and $2.2-2.8{\mu}g/g$ dry mass where the higher B concentration was applied. Application of 8 kg/ha B reduced the dry yield of 3rd-yr roots by 20% from 2745 kg/ha to 2196 kg/ha and 4th-yr roots by 26% from 4130 kg/ha to 3071 kg/ha. Ginseng seedlings and radish were grown under greenhouse conditions in nutrient culture with four B concentrations ranging from 0 mg/L to 10 mg/L. At 5 mg/L and 10 mg/L ginseng and radish developed typical leaf B toxicity symptoms similar to those described above for field-grown plants. Increasing B in the nutrient solution from 0.5 mg/L to 10 mg/L decreased, in a linear fashion, the root and leaf dry mass of ginseng, but not radish. Given the many similarities of ginseng and radish to B utilization, radish might be used as a timesaving model system for the study of B, and other micronutrients, in the slow-growing perennial ginseng.

• Journal of Life Science
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• v.17 no.11
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• pp.1477-1481
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• 2007

The mating systems of natural populations of Vicia tetrasperm in Korea were determined using allozyme analysis. The result suggests that V. tetrasperm is low rates of outcrossing or mix-mating outcrossing (self-fertilization, s < 0.5). At the population levels, the values of inbreeding coefficient of ten populations in Korea varied from 0.131 to 0.176, giving an average 0.154. For ten natural populations, multi-locus estimates of outcrossing (tm) was 0.333 across fifteen polymorphic loci, with individual population values ranging from 0.269 to 0.423. The differences between the tm and ts values were not close to zero (tm - ts > 0.154), indicating that biparental inbreeding was significant in the loci. The reason for relatively low outcrossing rates of some populations could be attributed to extensive consanguineous mating and isolation of flowering mature plants. Although heterozygote excess was observed in one natural population, most populations exhibited varying degrees of inbreeding and heterozygotes deficit. Thus, selection against homozygotes operated in the progeny populations throughout the life cycle.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.3
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• pp.119-125
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• 2017

Objective: In vitro culture of preimplantation embryos is improved by grouping embryos together in a drop of media. Individually cultured embryos are deprived of paracrine factors; with this in mind, we investigated whether the addition of a single embryo-secreted factor, interleukin-6 (IL-6), could improve the development of individually cultured embryos. Methods: Mouse embryos were cultured individually in $2{\mu}L$ of G1/G2 media in 5% oxygen and supplemented with a range of doses of recombinant mouse or human IL-6. Results: Mouse IL-6 increased hatching at doses of 0.01 and 10 ng/mL compared to the control (93% and 93% vs. 78%, p< 0.05) and increased the total number of cells at a dose of 0.1 ng/mL compared to the control ($101.95{\pm}3.36$ vs. $91.31{\pm}3.33$, p< 0.05). In contrast, the highest dose of 100 ng/mL reduced the total number of cells ($79.86{\pm}3.29$, p< 0.05). Supplementation with human IL-6 had a different effect, with no change in hatching or total cell numbers, but an increase in the percentage of inner cell mass per embryo at doses of 0.1, 1, and 100 ng/mL compared to the control ($22.9%{\pm}1.1%$, $23.3%{\pm}1.1%$, and $23.1%{\pm}1.1%$ vs. $19.5%{\pm}1.0%$, p< 0.05). Conclusion: These data show that IL-6 improved mouse embryo development when cultured individually in complex media; however, an excess of IL-6 may be detrimental. Additionally, these data indicate that there is some cross-species benefit of human IL-6 for mouse embryos, but possibly through a different mechanism than for mouse IL-6.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.4
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• pp.199-217
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• 1975

For the establishment of efficient method of potassium topdressing on rice the optimum time and amount were investigated and discussed on the basis of available data from nutriophysiological studies, soil characteristics and fertilizer trials in fields. The followings were pointed out. 1. According to yield rice plants require more potassium around heading under water culture. 2. Potassium involves in harvest index, filled grain ratio, grain weight and number of spikelets per panicle. 3. Potassium is lost after heading in most fields in spite of highest requirement during this period. 4. The higher $K_2O/N$ ratio in straw at harvest is, the higher the yield. 5. Relatively low efficiency of potassium fertilizer under the field condition may be due to improper application method rather than natural supply from soil and irrigation water. 6. Appropriate topdressing time appears at in effective tillering stage for the prevention of nitrogen excess and at 15 to 20 days after transplanting, ear formation stage and 5 days after heading for the prevention of soil reduction damage. Two times of topdressing for clayey soil and three times for sandy soil seems reasonable in practice together with nitrogen topdressing, 7. The reasonable ratio basal to topdressing of potassium fertlizer seems to be 2/3 and $N/K_2O$ ratio of fertilization for ear formation stage appeared also as 2/3.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.1
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• pp.43-53
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• 2020

The test conducted in this study was carried out for three years from 2013 to 2015 to investigate the optimal level of seeding amount and nitrogen fertilizer application to cultivate and produce the seeds of rye in Jangsu province, Jeollabuk-do. The variety of forage rye used in this experiment was 'Gogu', developed by National Institute of Crop Science, Suwon, Korea in 2004. The seeding rate was four levels (3, 5, 7 and 9 kg 10a^-1, respectively) while nitrogen fertilized with respective amounts of 0, 3, 6, and 9 kg 10a^-1. In Jangsu, the number of spike per m² and lodging ratio were increasing, while fertility rate, 1 liter weight, 1000-grain weight and seed productivity were decreased by increasing of seeding rate from 3 kg 10a^-1 to 9 kg 10a^-1. There was an increase in the number of spike per m², culm lengh, the number of grain per spike, lodging ratio and seed productivity, while productiove tiller, 1 grain weight, and 1 liter weight were decreased by increasing nitrogen fertilizer level from 3kg 10a^-1 to 9 kg 10a^-1. The best seeding rate and nitrogen fertilizer level for rye seed production were 5 kg and 6 kg 10a^-1, respectively, considering plant lodging, seed and fertilizer reduction and the prevention of pollution by excess fertilization.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.5
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• pp.468-475
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• 1992

In order to understand more clearly the integration between N-assmilation and C-metabolism in relation to N fertilization, a pot experiment with 5 different level of N fertilization(0, 5, 10, 25, 50 mM NO$_3$$_{[-10]}$ ) was conducted in Manchester, U.K. The peas (Pisum sativum L., cv. Early Onward) were sown in vermiculate (5 cm depth) and cultivated for 6 days under temperature controlled dark room conditions ($25^{\circ}C$). The plants received frequent irrigation with a nutrient solution: it was fertilized every 2 days, 3 times a day at 10h, 13h, 16h respectively. Elevated NO$_3$$^{[-10]}$ concentration, the activity levels of NR, NiR, total GS(crude extract), GS$_2$(plastid) in both root and shoot were increased and reached the peak in 5～25 mM, except NiR specific activity which increased its activity continually until 50 mM NO$_3$$^{[-10]}$ treatment. Total activities of GS (crude extract) in both root and shoot became higher than those of GS$_2$(Plastid), and the activity ratios of total GS in the crude extract and GS$_2$ in the plastids were 3.0 to 4.3 in root, but 3.2 to 10.6 in shoot. It was concluded that the reductants and A TP from OPPP itself should be enough to achieve the high rate of NR, NiR, GS$_1$, GS$_2$ in plant root and shoot for reduction or assimilation of nitrogen, but these enzyme activities might be inhibited by an excess of NO$_3$$^{[-10]}$ influx over the reduction capacity.