• Korean Journal of Agricultural Science
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• v.46 no.2
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• pp.229-237
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• 2019

The influence of dietary supplementation with a yeast culture on growth performance, fecal score and nutrient digestibility was evaluated in weaned pigs in a 6-week feeding trial. A total of 50 weaning pigs with an initial average body weight (BW) of $7.46{\pm}1.60kg$ were randomly allotted into 1 of 2 dietary treatments according to the initial BW. There were 5 replicate pens in each treatment with 5 pigs per pen. The dietary treatments were as follows: 1) control, basal diet (CON) and 2) 0.10% yeast culture, basal diet supplemented with 0.1% yeast culture (YC). The average daily feed intake was significantly improved with the dietary supplementation of the yeast culture compared with the control during phases 1 and 3. Overall (0 to 6 weeks), dietary supplementation with the 0.1% yeast culture had a significant effect on the feed conversion ratio (FCR). There was no significant difference in the fecal score between the CON and YC dietary treatments. In addition, no difference in the apparent total tract digestibility was observed between the CON and YC dietary treatments. Collectively, the results of this study indicate that dietary supplementation of 0.1% yeast only improved the feed intake of weaning pigs; however, yeast culture supplementation did not affect the average daily gain, feed efficiency, total tract digestibility of dry matter, and nitrogen and energy levels as well as the fecal scores.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.859-865
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• 2020

A total of 100 growing pigs (25.66 ± 1.55 kg) were used in a 16-week feeding trial. Pigs were randomly distributed into two treatment groups on the basis of body weight and sex. There were ten replicate pens per treatment, with five pigs (three barrows and two gilts) per pen. The dietary treatments for this trial were as follows: 1) Basal diet (CON) and 2) T1 (γ-aminobutyric acid, GABA), CON + 100 mg·kg-1 GABA. During weeks 0 to 6, the feed efficiency (G : F) in the T1 group was higher (p < 0.05) than that in the CON group, but no improvements in the average daily feed intake (ADFI) and average daily gain (ADG) were noted (p > 0.05). During the experimental period, the final body weight (BW) was improved (p < 0.05). However, no differences (p > 0.05) were noted in the apparent total tract digestibility (ATTD) of dry matter (DM) nitrogen (N). Meanwhile, there were no significant differences (p > 0.05) observed in the backfat thickness among the treatment groups. These results therefore indicate that supplementation with GABA may improve the overall growth performance but may not lead to differences in the nutrient digestibility and backfat thickness in growing-finishing pigs.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1215-1221
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• 2005

The purpose of this research was to compare the nutrient removal efficiency, and to estimate the net reaction time in order to calculate a "phase" transfer rate. SBR(SBR1) with flexible verticals and single reactor SBR(SBR1). Consequently, the removal efficiencies of $COD_{Cr}$, and $BOD_5$ in SBR1 and SBR2 were 91.5%, 97.5% and 90.4%, 97.3%, Respectively. Accordingly, the organic removal efficiency was not distinguished in both processes. In the T-N and T-P removal efficiencies, however, SBR1 obtained higher removal efficiency than SBR2, at 12.1% and 7.6% respectively. Also, in the experiment to estimate the "phase" transfer rate, SBR1 was higher than SBR2 Because SBR1 has two phases in the single reactor simultaneously, it has the buffer capacity to reduce the "phase" transfer time and provides a definite reaction condition.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.138-143
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• 2011

BACKGROUND: This study was conducted to investigate growth and yield of organically grown rice under a typhoon during a fall. The treatments included NPK chemical fertilizer, compost, oilcake, oilcake 2X, hairyvetch, and vetch+rye. METHODS AND RESULTS: Nutrient applications were made at rates equivalent to approximately 0.9 kg of actual N per acre. Oilcake and hairyvetch treatments had the lowest C:N ratio, but compost had the highest C:N ratio of 34:1. Rice treated by organic nutrient sources had great growth and development at the beginning of the growing season but had depressed growth and yield at the harvest. Oilcake 2X-treated rice in early growing season, especially, showed better growth and development than rice treated by other nutrient sources but was severely lodged at the harvest season due to the typhoon. Compost treatment with high C:N ratio slowly released inorganic N and produced poor rice growth and yield; however, it recued rice lodging. N uptake was the greatest for the oilcake 2X and vetch+rye treatments but the lowest for the compost, which was the similar pattern to the N use efficiency; the greatest and lowest N use efficiency was observed for the oilcake 2X (55%) and compost (5%), respectively. CONCLUSION(s): Rice lodging should be prevented by reducing the excessive nitrogen supplement, resulting from the lower C:N ratio of the organic materials as well as prevented by the radical midsummer drainage. Vetch+rye treatment with 25:1 of C:N had optimum vegetative growth and reduced rice lodging, which increased N use efficiency and yield.

• Journal of Environmental Science International
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• v.12 no.7
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• pp.791-799
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• 2003

This study was carried out to get more operational characteristics of the sequencing batch biofilm reactors with media volume/reactor volume ratio of 15 %, 25 % and 35 %. Experiments were conducted to find the effects of the media packing ratio on organic matters and nutrients removal. Three laboratory scale reactors were fed with synthetic wastewater. During studies, the operation mode was fixed. The organic removal efficiency didn't show large difference among three reactor of different packing media ratios. However, from the study results, the optimum packing media ratios for biological nutrient removal was shown as 25%. The denitrifying PAOs could take up and store phosphate using nitrate as electron acceptor.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.770-776
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• 2000

This paper represents our efforts to diagnose nutrient stresses using physiological instruments in cucumber plants. The stresses could be detected by measuring and analyzing the difference of chlorophyll content, photosynthetic efficiency(Fv/Fm), differential temperature(DT), stomatal resistance and light absorbance values between deficient and controlled plants. From the all over experiments, the stresses could be first diagnosed in the 8th day after treatment and the overall diagnosis rate was estimated at more than 50%.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1008-1013
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• 2007

The objectives of the paper were to identify appropriate best management practices (BMPs) for reducing nonpoint source (NPS) pollutant loadings and to simulate the effects of the application of the several BMP scenarios on the study watershed using Agricultural Nonpoint Source (AGNPS) model. AGNPS model was calibrated and validated for runoff, sediment yield, and nutrient components using the observed hydrologic and water quality data. The simulated runoff, sediment, and nutrient components were well agreed with observed data. The validated AGNPS was applied to estimate the NPS pollution removal efficiency for BMP scenarios which were selected considering the pollutant characteristics of the study watershed.

• Korean Journal of Environmental Agriculture
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• v.24 no.3
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• pp.303-313
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• 2005

Agricultural environmental indicators (AEIs) are useful tool for evaluating environmental performance induced by agri-environmental policy measures. General and specific criteria have been set to assess the linkages between policy measures and environmental states. In addition, a number of specific AEIs such as nutrient balance indicators and farm management indicators have been posit to review environmental performance associated with agri-environmental policy measures. The proposed environmental subjects encompass soil quality, qualities of underground and surface water, water resource preservation, species and genetic diversity, diversity for wildlife habitats, and agricultural landscapes. The developed AEIs may contribute to establishment or adjustment of environmental targets and ex-ante or ex-post evaluation for environmental performance associated with policy measures. In addition, the AEIs may be useful to consider introduction of new agri-environmental measures and enhance policy efficiency by assessing environmental performance, considering specific locality, and harmonizing support measures.

• Journal of Korean Society of Forest Science
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• v.34 no.1
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• pp.73-85
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• 1977

The nutrient elements which are used in forest fertilization vary from country to country. The development of forest fertilization is influenced by different national interests and/or economic situtations. The fertilized area/year of each country is shown. As one can see, Korea will have one of the largest fertilized forest area in the world. Nevertheless, attention needs to be paid from the technical viewpoint, since the development has been very rapid. The fertilization techniques, kinds of nutrient element, amounts of dosage, types of fertilizers, estimation of their efficiency, leaf analysis, ecological or physiological aspects of forest fertilization, tree species, wood qualities, forest vegetation, damages such as deseases, insects, frost, wind and snow, are discussed in relation to forest fertilization. Finally, the problem of eutrophication of water is discussed. The technical assessment will become necessary in introducing new techniques into the field.

• Journal of Ginseng Research
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• v.44 no.4
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• pp.627-636
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• 2020

Background: Cultivation of medicinal crops, which synthesize hundreds of substances for curative functions, was focused on the synthesis of secondary metabolites rather than biomass accumulation. Nutrition is an important restrict factor for plant growth and secondary metabolites, but little attention has been given to the plasticity of nutrient uptake and secondary metabolites synthesis response to soil nitrogen (N) change. Methods: Two year-field experiments of Sanqi (Panax notoginseng), which can synthesize a high level of saponin in cells, were conducted to study the effects of N application on the temporal dynamics of biomass, nutrient absorption, root architecture and the relationships between these parameters and saponin synthesis. Results: Increasing N fertilizer rates could improve the dry matter yields and nutrient absorption ability through increasing the maximum daily growth (or nutrient uptake) rate. Under suitable N level (225 kg/ha N), Sanqi restricted the root length and surface and enhanced the root diameter and N uptake rate per root length (NURI) to promote nutrient absorption, but the opposite status of Sanqi root architecture and NURI was found when soil N was deficient. Furthermore, increasing N rates could promote the accumulation of saponin in roots through improving the NURI, which showed a significant positive relationship with the content of saponin in the taproots. Conclusion: Appropriate N fertilizer rates could optimize both root architecture and nutrient uptake efficiency, then promote both the accumulation of dry matter and the synthesis of saponins.