• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.487-493
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• 2013

The effects of long-term fertilization on soil biological properties and microbial community structure in the plough layer in a rice paddy soil in southern Korea were investigated in relation to the continuous application of chemical fertilizers (NPK), straw based compost (Compost), combination these two (NPK + Compost) for last 40 years. No fertilization plot (Control) was installed for comparison. Though fertilization significantly improved rice productivity over control, the long-term fertilization of NPK and compost combination was more effective on increasing rice productivity and soil nutrient status than single application of compost or chemical fertilizer. All fertilization treatments had shown significant improvement in soil microbial properties, however, continuous compost fertilization markedly increased soil enzyme and microbial activities as compared to sole chemical fertilization. Results of microbial community structure, evaluated by EL-FAME (ester-linked fatty acid methyl esters) method, revealed big difference among Control, NPK, and Compost. However, both Compost and Compost+NPK treatments belonged to the same cluster after statistical analysis. The combined application of chemical fertilizer and organic amendments could be more rational strategy to improve soil nutrient status and promote soil microbial communities than the single chemical fertilizer or compost application.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.677-681
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• 2016

Excessive nitrogen fertilization influences crop yields and quality as well as environmental pollution. In this study, yields, nitrogen use efficiency and free sugar contents of burdock (Arctium lappa L.) were evaluated at different levels of nitrogen fertilization. Nitrogen fertilizer was applied at 5 levels (0, 50, 100, 150, 200%) based on the conventional fertilization ($N=230kg\;ha^{-1}$), and phosphate and potassium fertilizer were treated by conventional P and K fertilization ($P_2O_5-K_2O=140-210kg\;ha^{-1}$) in all plots. The root yields of burdock were the highest in N 100~150% treatment plots. Nitrogen use efficiency and nitrogen recovery decreased from over N 150% treatment. Nitrogen uptake of root was greater than that of shoot in N 50~200% treatments. Fructose contents in root were inversely proportional to the level of nitrogen fertilization. As considering nitrogen recovery and root quality, economical burdock yield was obtained in N $230kg\;ha^{-1}$.

• Journal of agriculture & life science
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• v.46 no.2
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• pp.63-73
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• 2012

This study was conducted to investigate effects of fertilization treatments (non-fertilizing, deep-fertilizing 20g, 50g, 100g, and surface-fertilizing 20g) on survival rate, growth performances, and seedling quality index (SQI) of container seedling and bare root seedling of Pinus densiflora in the field. There were no significantly differences in survival rate among fertilization treatments in the field. Besides, there was no toxic effect on seedling by over 100g fertilization in deep-fertilizing treatment. The root collar diameter and height of P. densiflora in both seedling types were the highest at 100g fertilization in deep-fertilizing treatments, and the biomass products and SQI were the same as above growth of root collar diameter and height. In most of the treatments, container seedlings showed better growth performances than bare root seedlings. In optimal fertilization, effect of fertilization was higher in container seedling than bare root seedling.

• The Korean Journal of Ecology
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• v.26 no.2
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• pp.59-64
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• 2003

We examined the effects of fertilization [control (C), 200 kg N ha^{-1} + 25 kg P ha^{-1}$ (LNP), and 400 kg N $ha^{-1} + 50 kg P ha^{-1}$ (HNP)] on fine root (＜ 2 mm diameter) dynamics using monthly soil coring method in a 39-year-old Pinus rigida plantation of central Korea. The average fine root biomass (live + dead) (kg $ha^{-1}$ $\pm$ SE) during the first growing season for C, LNP, and HNP was 1301 $\pm$ 54, 1084 $\pm$ 47, and 1328 $\pm$ 22, respectively. The fine root production (kg $ha^{-1}$ $\pm$ SE) was 2394 $\pm$ 128 for C, 2048 $\pm$ 101 for LNP, and 2768 $\pm$ 150 for HNP, respectively. Over the same period, fertilization treatments had impact on N and P concentrations of live fine root. Nitrogen and P inputs (kg $ha^{-1}$ $yr^{-1}$) into the soil through fine root turnover for C, LNP, and HNP were 16.6 and 0.9, 17.2 and 0.9, and 24.1 and 1.6, respectively. There were no significant differences in fine root biomass and production during the first growing season after fertilization. However, fertilization increased fine root N and P concentrations, and in consequence resulted in increased N and P inputs into soil through fine root turnover.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.3
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• pp.387-394
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• 2012

Fertilization rates were over 90% when sperm from black porgy Acanthopagrus schlegelii acclimated and raised in freshwater and black porgy raised in seawater were fertilized with eggs from female black porgy raised in seawater, although cryopreserved sperm were significantly lower in fertilization rates than non-cryopreserved sperm. From the observations of embryos development at different salinities (0, 10, 20 and 32 psu) within 3 hours upon fertilization (16 cell stage), all were dead at 0 psu. However, the development process and speed at 10 and 20 psu were the same as at 32 psu. But, many developing embryos were egg envelope injury at low-salinities of 10 and 20 psu unlike at 32 psu. This is attributable to osmotic shock. Hatching rate of embryos at 32 psu was 60% or so, whereas low as 5% or less were successfully hatched at 10 and 20 psu, implying that osmotic shock could be responsible for the failure of embryo development.

• Journal of Embryo Transfer
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• v.10 no.2
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• pp.131-138
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• 1995

Essential and non-essential amino acids supplemented to culture medium stimulate mammalian embryo development in vitro. Amino acids such as glycine, taurine and alanine are concentrated in the lumen of oviduct and uterus and it can he thought that these amino acids may have physiological role on fertilization and embryo development. Our aim of this experiment was to investigate the effects of essential and non-essential amino acids, taurine or glycine supplemented to fertilization medium on the cleavage and subsequent in vitro development of bovine oocytes matured and fertilized in vitro. Immature oocytes were obtained from slaughtered Holstein cows and heifers and matured in TCM199 containing 10% fetal calf serum, 2.5 $\mu$g /mL of FSH and LH and 1 $\mu$g / mL of estradiol with granulosa cells in vitro. After maturation, oocytes were coincubated with sperm in fertilization medium supplemented with Minimum Essential Medium (MEM) essential and non-essential amino acids, taurine (3.75 mM) or glycine (10 mM) for 30 hours in vitro. Inseminated oocytes were cultured in synthetic oviduct fluid medium (SOEM) containing MEM essential, non-essential amino acids and 1 mM glutarnine up to 8 days after fertilization.Supplementation of fertilization medium with MEM essential and non-essential amino acids lowered significantly (p<0.05 and p<0.001) the cleavage rate after 30 hours of IVF (53.3%) and at Day 3 (62.7%: Day 0: the day of I VF) compared to control (64.3% and 77.3%, respectively). Subsequent developmental rates to morulae (Mo) and expanding blastocysts (ExBL) also significantly decreased (p<0.001 and p<0.05 for Mo and ExBL) when oocytes were coincubated with sperm in the medium containing MEM amino acids. Taurine added to fertilization medium have not increased the cleavage rate over the control, whereas glycine showed significantly lower (p<0.01) cleavage rate at Day 3 than that of taurine, but there was no significant difference in the developmental rates to Mo and ExBL of bovine embryos irrespective of the supplementation of taurine or glycine to fertilization medium. In conclusion, supplementation of fertilization medium with essential and non-essential amino acids, taurine or glycine has no beneficial effect on in vitro cleavage and development of bovine oocytes matured and fertilization in vitro.

• Agricultural and Biosystems Engineering
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• v.7 no.1
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• pp.18-26
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• 2006

In-field site-specific nitrogen (N) management increases crop yield, reduces N application to minimize the risk of nitrate contamination of ground water, and thus reduces farming cost. Real-time N sensing and fertilization is required for efficient N management. An 'on-the-go' site-specific N management system was developed and evaluated for the supplemental N application to com (Zea mays L.). This real-time N sensing and fertilization system monitored and assessed N fertilization needs using a vision-based spectral sensor and controlled the appropriate variable N rate according to N deficiency level estimated from spectral signature of crop canopies. Sensor inputs included ambient illumination, camera parameters, and image histogram of three spectral regions (red, green, and near-infrared). The real-time sensor-based supplemental N treatment improved crop N status and increased yield over most plots. The largest yield increase was achieved in plots with low initial N treatment combined with supplemental variable-rate application. Yield data for plots where N was applied the latest in the season resulted in a reduced impact on supplemental N. For plots with no supplemental N application, yield increased gradually with initial N treatment, but any N application more than 101 kg/ha had minimal impact on yield.

• Clinical and Experimental Reproductive Medicine
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• v.17 no.2
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• pp.123-128
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• 1990

Capacitation of mouse spermatozoa in vitro is brought about by epididymal secretions released into the m-Tgrode medium at the time of sperm collection. Epididymal mouse sperm suspension achived by centrifugation were preincubated for a total of 120min with aliquants being removed at 5, 30 and 120min. By gently centrifugation and resuspending in fresh medium, the fertilizing rate of unwashed 5-and 30-min suspensions was increased such that 30-min washed samples did not differ significiantly from full capacitated, highly fertile 120-min unwashed samples. When epididymal suspension was added fertilization of cumulus intact oocyte was markedly inhibited, although fertilization of zona free oocytes was unaffected. Washing sperm suspensions preincubated in the absence of $Ca^{2+}$ with the subsequent introduction of exogenous $Ca^{2+}$ resulted in a significant increase in fertilization rates over equivalent unwashed samples.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.3
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• pp.175-181
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• 1991

The purpose of this experiment was to evaluate the effects of shade and levels of N fertilization on the dry matter yield and chemical compositions of orchardgrass grown under floor of chestnut tree. Shading conditions consist of $S_0$, (full light), $S_1$, (about 6OC4 shade) and $S_2$, (about 70% shade). And, nitrogen fertilizer was applied at 3 levels, O($N_0$), 12($N_1$), and 30($N_2$) kg per 10a, respectively. The results are may be summarized as follows: 1. Maximum total dry matter yield of $S_0$, was obtained about 1.28 ton/lOa at $N_2$, level. But, total dry matter yields of N levels in $S_1$, and $S_2$, were decreased about 42-45% compared with $S_0$. 2. The response of the dry matter yield to N fertilization were differences between shading and levels of N. Thus, the dry matter yield of $S_1$, increased almost linear up to about 30 kg/l0a level, while the dry matter yield of S, was increased slightly up to 30 kgIl0a. But. $S_2$, was increased up to 12 kg/lOa and then decreased slightly with N fertilization over the 12 kg/l0a. 3. Average increase in total dry matter yield to N fertilization were 23.85 kg, 7.97 kg and 5.08 kg DM for $S_0$, $S_1$, and $S_2$, respectively. 4. The level of 12 kg N/lOa is the limiting N level to obtain dry matter production under 60-709 shading conditions. 5. The contents of crude protein arid nitrate nitrogen were increased with shading and incremental N fertilization up to 30 kg/l0a. But, water soluble carbohydrate content was decreased greatly with high shading and high levels of N. 6. Nitrate nitrogen content indicated highly significant positive correlation with crude protein, but significant negative correlation with water soluble carbohydrate content. 7. At 30 kg N level with $S_1$, was necessary to exceed the potentially toxic nitrate nitrogen level of 0.20%.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.298-302
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• 2006

This study was carried out to establish low-input fertilization and seeding technique using the simultaneous with seeding and fertilizer application machine and band spotty applicator which were manufactured for experiment during cultivation of mulching for peanut(Arachis hypogaea L.). The labor hour for seeding by simultaneous with seeding and fertilizing machine was appeared over 90% reduction effect compared with control plot($17.3hr\;10a^{-1}$). In band spotty fertilization plots, the emergence date was delayed about 4 days and the seedling stand rate was decreased 11~18% compared with control plot(man power). The content of total nitrogen of soil after experiment was increased while the contents of organic matter, available phosphate and exchangeable potassium were decreased than before experiment. The content of nitrogen forming nitrate was increased in band spotty fertilization(BSF) plots by increasing the amount of applied fertilizer from early growth stage till the middle growth stage. Growth rate was increased in band spotty fertilization plots and the absorbed amount of phosphate and potassium for peanut were increased in 70% band spotty fertilization plot compared with control plot. Yield of peanut was increased 70% in band spotty fertilization plot due to high pod kernel ratio and ripened pod rate compared with control plot($3,150kg\;ha^{-1}$). It was found that 70% band spotty fertilization was more effective as fertilization method to reduce both environmental pollution and chemical nitrogen fertilizer in plastic film mulching cultivation of peanut.