• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.2
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• pp.134-140
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• 2021

This study was carried out to study the effect of supplementary nitrogen fertilization application time according to regrowth date on growth date on growth characteristics, feed value, and productivity of Italian ryegrass (Lolium multiflorum Lam.; IRG) from 2019 to 2021 in Cheonan region. In order to determine the regrowth time, IRG was cut from experimental plots 3cm above soil level and the time when 1cm grew was judged as the regrowth time. The regrowth dates were February 15^th and February 12th in 2020 and 2021 respectively. The experimental design was a randomized block design with three replications. The treatments were no fertilizer, immediately after the regrowth period, after 10 days of the regrowth period, and after 25 days of the regrowth period. Dry matter yield of IRG was significantly influenced by the supplementary N-fertilization application time. Dry matter yield was reduced for the delayed application time. The dry matter yield of immediately after the regrowth period was approximately 34.8 % higher than that no fertilizer application. In delaying the supplementary N-fertilization application time resulted in increased crude protein content. However, no significant statistical difference was neutral detergent fiber and acid detergent fiber(p>0.05). After wintering, productivity of IRG reduced for the delayed application time. Therefore, it is essential to application N-fertilizer immediately after the regrowth period for high productivity of IRG.

• Journal of Bio-Environment Control
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• v.14 no.1
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• pp.38-45
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• 2005

This research was conducted to determine the effect of fertilization programs on crop growth, nutrient uptake and yield of strawberry and salt accumulation in PE film house soil. To achieve these, experiments were conducted through two years with various fertilization program such as traditional fertilization(A), recommended fertilization of Rural development administration (B), Tochigi prefectural experiment station (C) and Nonsan strawberry experiment station (D), and control (E). In 1st year, statistical differences in growth characteristics were not observed among treatments except (E). Yield per 10 was the highest in (D) followed by (A), (B), (C) and (E) and there was the statistical difference between (D) and (E). In the 2nd year experiment, growth characteristics and yield showed similar trends to those of 1st year experiment. In the results of soil analysis of 2nd year, the soil pH of all treatments were in the acceptable range, while electrical conductivity of (A) and (D) were 2.36 and 2.19 %$dS{\cdot}m^{-1}$, respectively. After finishing of strawberry cultivation, nitrate concentration in soil solution of (A) and (D) were 74.6 and 65.0%$mg{\cdot}L^{-1}$ and Na in those were 3.71 and 3.53 $cmol+kg^{-1}$, respectively. Above results indicated that (A) and (D) were good fertilization program for strawberry cultivation, but those also resulted in accumulation of $NO_{3-}N$ and Na in PE house soil.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.1
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• pp.56-62
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• 1986

Fertilization response on production and quality of flue-cured tobacco as to different level of nitrogen, phosphorus, and potassium were studied in a field experiment. The results were summarized as follows: 1. Growth and yield of flue-cured tobacco were significantly better in higher nitrogen fertilization levels, regardless of soil fertility, but the negative correlation was recognized between the quality of leaves and the amounts of nitrogen application. While, both fertilizers of phosphorous and potassium did not have should little effect on the tobacco yield and quality. 2. The optimum ratio of N, P, and K fertilizer applications were decided by the appearance of the proper yield and the best quality of tobacco leaves. The proportion of N:P:K was 2:1:4. 3. The single effect (Complete plot minus Non-fertilized plot) of N, P, and K on yield and quality of cured leaf was greatly affected by nitrogen, but the combined effect (Nutrient deficiency plot minus Non-fertilzier plot) of that were only slightly affected by P and K.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.2
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• pp.172-175
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• 2003

The regression equations of dry weight of planktonic biomass upon physico-chemical characteristics of fifteen ponds in three replicates under the influence of artificial feed, broiler manure, buffalo manure, N:P:K (25:25:0) and a control pond was obtained after one year of experimental period by using stepwise regression method. Water samples from each of the ponds were analyzed daily. However, the average values were calculated on the basis of 15 day intervals designated as fortnight. In artificial feed supplemented pond the regression of average nitrates on dry weight of planktonic biomass accounted for 71.7% of the variation in biomass. In broiler manure fertilization pond the regression of total nitrogen on dry weight of planktonic biomass held it responsible for more than 74.6% of variation in biomass. In buffalo's manure fertilized pond more than 82% of the variations in biomass were due to total nitrogen. In case of N:P:K (25:25:0) treated pond 66% of the variation in the dry weight of planktonic biomass was due to average nitrates. The control pond showed the dependence of biomass on light penetration. This equation explained more than 62 percent of variation in biomass. Other variables also showed some contribution towards variation in biomass under all the treatments in these regression studies.

• Journal of Korean Society of Forest Science
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• v.95 no.1
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• pp.82-90
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• 2006

To examine the effects of nitrogen and phosphorus fertilization on soil nitrogen (N) mineralization, we monitored rates of soil nitrogen mineralization and nitrification in 41-year-old pitch pine (Pinus rigida Mill.) and Japanese larch (Larix kaempferi Gordon) stands growing on similar soil condition in central Korea. For this study, we used the buried-bag incubation method. Fertilizers were applied at three levels [control (C), 200 N kg/ha+25 P kg/ha (LNP), and 400 N kg/ha+50 P kg/ha(HNP)] on 5 June, 1996. Mineral soils (0~20 cm) were incubated 6 times with 45-day-interval from 5 June 1996 to 4 June 1997. Initial soil moisture contents were significantly different among sampling dates and between tree species. Initial soil moisture contents were 32% for C, 28% for LNP, and 26% for HNP at the P. rigida stand, and 31% for C, 31% for LNP, and 33% for HNP at the L. kaempferi stand, respectively. Mean daily N mineralization rates were significantly different among sampling dates and treatments. Annual net N mineralization and nitrification were also significantly different between the two tree species. The annual net N mineralization was 10.6 kg/ha/year for C, 23.3 kg/ha/year for LNP and 6.6 kg/ha/year for HNP at the P. rigida stand, and 2.0 kg/ha/year for C, 12.1 kg/ha/year for LNP and 16.7 kg/ha/year for HNP at the L. kaempferi stand. The annual nitrification was 2.8 kg/ha/year for C, 7.6 kg/ha/year for LNP and 4.3 kg/ha/year for HNP at the P. rigida stand, and 4.3 kg/ha/year for C, 14.8 kg/ha/year for LNP and 6.6 kg/ha/year for HNP at the L. kaempferi stand. The ratios of annual net nitrification to annual net N mineralization were 26% for C, 33% for LNP, 65% for HNP at the P. rigida stand, and 100% for C, 100% for LNP, 40% for HNP at the L. kaempferi stand, respectively. This study indicates that N mineralization in forest may be different by the predominant tree species and fertilization even under similar environments. It is likely that the quality of organic matter might control nitrogen mineralization and nitrification in soils.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.2
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• pp.121-126
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• 1996

To investigate the effects of potassium($K_2O$) fertilization levels on the dry matter(DM) yield, nutrition yield, and $K_2O$ efficiency of forages in mixed sward of alfalfa-grasses, a field experiment arranged by randomized complete block design with five treatments(0, 60, 120, 180 and 240kg $K_2O$/ha) was conducted at National Livestock Research Institute in Suwon, September, 1990 to February, 1993. During two years, average DM yields of forage increased as $K_2O$ fertilization level was increased, but no significant difference was found between DM 10,617kg of $K_2O$180kgha and DM 10,845kg of $K_2O$ 240kg/ha. Crude protein and energy productivity of forages increased as $K_2O$ fertilization level was increased, and the increasing degree was highest between $K_2O$ 120kg and 180kg/ha fertilization. With increasing $K_2O$ fertilization, mineral contents tended to increase in K and WCa+Mg equivalent ratios, to decrease in Mg, but not to be regular in the other elements. Efficiency of $K_2O$ was relatively high at $K_2O$ 180kgha fertilization, which produced DM 12.2kg, net energy lactation 67.3M.J, starch equivalent 6.2kStE and total digestible nutrients 7.6kg per Ikg $K_2O$. Therefore, potassium($K_2O$) fertilization levels must be applied with I8Okg/ha for a reasonable management in mixed sward of alfalfa-grasses.

• Clinical and Experimental Reproductive Medicine
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• v.22 no.3
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• pp.293-299
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• 1995

Objective: To investigate the effects of sperm morphology and their co-incubation with oocytes on the outcome of IVF and ICSI. Design: Strict morphology of washed sperm was assessed by Diff-Quick staining method before or after insemination. And the relationships between strict morphology and outcome (fertilization, embryo development and pregnancy) of IVF(with co-incubation) and ICSI (without co-incubation) were determined. Patients: Two-hundreds-and-sixty-three cycles of IVF and ninety-six cycles of ICSI were analyzed in order to clarify the influence of strict sperm morphology of spermatozoa on outcome of IVF and ICSI. These were divided into four groups. according to fertilization method and sperm morphology(Group 1: IVF, ${\geq}$12%, n:227; Group 2: IVF, <12%, n:36; Group 3: ICSI, ${\geq}$ 12%, n=48; Group 4: ICSI, <12%, n=48). Results: The fertilization rates of better morphology groups were higher than those of poor groups: Group 1(68.1%) > Group 2(62.1%), Group 3(78.1%) > Group 4(71.5%). There was no difference in embryo cleavage rates among four groups (>90%), Regarded with the good embryo rates, Group 1(56.8%) was significantly higher than Group 2(42.3%)(P<0.01), but there was no difference between Group 3(64.7%) and Group 4(61.2%). The pregnancy rates were also higher in better morphology groups as well as fertilization rates: Group 1(34.8%)> Group 2(16.7%)(p<0.05), Group 3(40.0%) > Group 4(23.0%)(p=0.08). Conclusion: Co-incubation with poor morphology sperm might adversely affect the quality of embryos. And strict sperm morphology may represent the ability to establish successful pregnancy. In short, the strict sperm morphology can be a good predictor of IVF and ICSI outcome.

• Korean Journal of Agricultural Science
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• v.44 no.2
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• pp.211-220
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• 2017

We conducted this study to determine the recommended application rate of fertilizer for Houttuynia cordata Thunb cultivation. The effects of various application levels of N, $P_2O_5$, and $K_2O$ fertilizers on the growth of this plant were investigated and the associated changes in soil properties were evaluated in the field. Soil pH at harvest time of Houttuynia cordata Thunb did not differ from that before fertilization, whereas EC tended to decrease during cultivation. The soil organic matter (SOM) and available phosphorus increased after treatment, and the amount of applied fertilizer ($P_2O_5$) and available phosphorus were proportional. The nitrogen absorption amount increased in N 100% treatment, but decreased in N 150% treatment. The phosphorus absorption amount rose with the fertilizer treatment concentration until $P_2O_5$ 150% treatment. The amount of absorbed potassium decreased in treatments with $K_2O$ 150% and $K_2O$ 200%. The plant length was the longest in N 100%, $P_2O_5$ 150%, and $K_2O$ 200%. The stem diameter was estimated to be 3.46 - 3.67 mm in N 100 - 200% treatment, 3.55 - 3.67 mm in $P_2O_5$ 100 - 150%, and 3.79 mm in $K_2O$ 200%. The number of tillers did not differ amongst fertilization treatments. The fresh weight was summed to be 3.67 ton/10 a in N 100% treatment, 3.79 Mg/10 a in $P_2O_5$ 150%, and 3.83 Mg/10 a in $K_2O$ 150%. Thus, the relationship between the fertilizer amount and yields of the plant showed that the most economical quantity of fertilizers should be 10.2 N kg/10 a, 5.5 $P_2O_5$ kg/10 a, and 8.2 $K_2O$ kg/10 a for Houttuynia Cordata Thunb.

• Clinical and Experimental Reproductive Medicine
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• v.32 no.2
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• pp.149-154
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• 2005

연구목적: 정자의 첨체상태는 수정능과 상관관계가 있다. 본 연구는 사람 정자의 동결보존 시 Fertilization promoting peptide (FPP) 처리가 첨체 유지에 효과가 있는지를 알아보고자 실시하였다. 연구재료 및 방법: 사람 정자는 정액검사를 의뢰한 시료를 사용하였으며, 적정농도를 조사하기 위하여 25, 50, 100 nM FPP를 신선정자에 처리한 뒤 시간별로 첨체의 변화를 조사하였다. 또한 적정화된 50 nM FPP를 정자의 동결-융해 시에 처리한 뒤 첨체 변화를 조사하였다. 첨체 변화는 FITC - pisum sativum lectin (PSA) 염색방법을 이용하여 조사하였다. 결 과: FPP 농도 변화와 처리시간에 따른 사람 정자의 첨체 변화를 조사하였던 바, 50 nM FPP 처리군에서 대조군보다 높은 온전한 첨체비율을 얻을 수 있었다. 정자의 동결-융해 시, 동결액과 융해액에 50 nM FPP 첨가가 온전한 첨체를 유지하는 비율을 조사하였던 바, 신선 정자의 결과보다는 유의하게 낮지만 무 처리군보다 유의적으로 높은 온전한 첨체를 얻을 수 있는 것을 알 수 있었다. 또한 동결액에만 또는 융해액에만 50 nM FPP 처리를 하더라도 무 처리군보다 유의하게 높은 온전한 첨체 비율을 획득할 수 있음을 알 수 있었다 (p<0.001). 결 론: 사람 정자의 동결보존 시 50 nM FPP 첨가는 자발적으로 발생하는 첨체반응을 억제하고, 온전한 첨체를 유지할 수 있어 수정능 보유에 기여할 수 있을 것으로 사료된다.