• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.107-111
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• 2006

This study was to verity that the uptake inhibition and accumulation of nitrogen in different potassium levels. Lettuce was used as model plant in this study and grown in pot of 10cm's in diameter and depth with mixture media of vermiculite and perlite under supply of different culture solution for three weeks. Nitrogen absorption at root was inhibited by increased potassium concentration in nutrient solution, and nitrate accumulation of plant was depended on absorption of nitrogen because nitrate content of 0 K level was 4-5 times higher than that of 2 K level, Concentration of ascorbic acid was decreased by increasing the nitrogen absorption, since ascorbic acid (AsA) content of 2K level was higher than those of OK level in both of old leaf and flesh leaf.

• Preventive Nutrition and Food Science
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• v.8 no.4
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• pp.401-405
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• 2003

This study was conducted to find gender differences in physical activity, dietary habit and nutrient intake in 4∼6th grade students in elementary school. Physical activity assessment showed that males significantly engaged in more vigorous activity with longer duration than females. It was found that females skipped their breakfast more often and had more snack than males. On the other hand, males were more indulged in peaky eating, despite their good practice of drinking milk. Twenty-four hour dietary recall revealed that energy intakes in both males and females were not sufficient. Furthermore, subjects, regardless of gender, consumed marginal intakes of Ca and Fe. Special attention should be given to marginal intakes of Ca in the subjects. Due to low Fe intake in females, more caution should be taken to include a meal which can enhance iron absorption. It might be suggested that effective intervention strategies need to be developed and implemented to choose nutrient dense foods and activities that lead to better health.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1995.10a
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• pp.85-86
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• 1995

수경재배 방식은 고품질의 작물생산, 토지의 고도이용, 연중재배 등과 같은 측면에서 많은 관심을 같게 되었다. 최근 선진국을 중심으로 작물생산에서 종합적인 환경제어기술, 생산과정의 자동화 및 계획 생산을 목적으로 하는 식물공장이 등장하게 되었다. 그러나 이들 재배방식간에 작물생산과정에서 재배환경의 차이로 인한 작물의 생리생태적 변화를 연구한 문헌은 미흡한 편이다. (중략)

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1998.05a
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• pp.158-161
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• 1998

고품질 청정채소에 대한 소비자의 선호가 높아지고 있어 신선채소의 규격생산, 주년 대량생산이 가능한 양액재배 방식을 근간으로 한 식물공장이 21세기 새로운 원예작물 생산시스템으로 대두되고 있다. 이들 생산시스템의 최적환경이 구명되어 있지 않은 실정으로 채소의 품질과 비용면에서 효율성 제고의 필요성이 제시되고 있다. (중략)

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.181-181
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• 2017

Global warming and climate change have been one of the most important problems last 2 decades. Global warming is known to cause abnormal climate and influence ecology, food production and human health. According to climate change model global warming is causing expansion of drought and increase of evaporation. Therefore, securing water in agriculture has been an important issue for crop cultivation. As potato is susceptible to drought, water shortage generally results in decrease of yield and decrease of biomass. In this research, we investigated characteristics of inorganic nutrient absorption and growth of plants grown under drought condition. Plants were sampled in sites of Cheong-ju and Gangneung, where the severity of drought stress were different. During the growth period in Gangneung, total rainfall in 2016 decreased by 50% compared with those in last 5 years average. Especially, there was almost no rain in tuber enlargement period (from mid-May to mid-June). On the other hand, the total rainfall in of Cheong-ju was is similar to those in last 5 years average. Inorganic components including K, Ca and Mg and plant growth factors such as plant length, stem length, leaf area index and plant biomass were investigated. Tuber yields in both areas were investigated at harvest. Growth period of plants was is longer in Cheong-ju than that in Gangneung. Contents of all inorganic components were higher in plants grown in Cheong-ju than in Gangneung. The results were attributed to higher production of plant biomass in Cheong-ju. Considering the results, severe drought stress conditions in Gangneung accelerated plant aging and resulted in low plant growth. Although total yield was greatly reduced under drought stress the rate of commercial yield was is not significantly different with non-drought conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.4
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• pp.276-280
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• 2013

D. kaki and D. lotus are used as rootstocks for astringent persimmons in Korea but characteristics of their seedlings have not been determined. In this experiment, their seeds were sown in 3-L pots on April 18 and the seedlings were grown until October 24. Growth and nutrient absorption were compared at the end of the season after destructively harvesting the seedlings. Seedling growth of D. lotus was much faster than that of D. kaki in terms of total stem length, stem diameter, and number of leaves. However, chlorophyll value and specific leaf weight were higher in D. kaki than in D. lotus. Dry weight of D. lotus was 3.6- and 3.7-fold higher than that of D. kaki in above-ground parts and the root, respectively. D. kaki seedlings were characterized by higher concentrations of N, P, K, Ca, and Mg in the leaves, stem, or the root. However, total contents of the elements were 1.8- to 3.7-fold higher in a D. lotus seedling due to its greater dry weight. Since D. lotus seedlings absorbed more inorganic elements on a tree basis and grew more vigorously than D. kaki seedlings, the level of fertilization for astringent persimmons should be adjusted depending on rootstocks to maintain the trees at the optimum vigor.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.189-196
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• 2011

The objective of this study was to investigate the effects of light intensity and electrical conductivity (EC) of nutrient solution during short day treatment in an ebb and flow systems on the growth and nutrient uptake of potted Kalanchoe blossfeldiana 'Rako' and the nutrient accumulation of growing medium. Nutrient concentrations in the growing medium were also analyzed to investigate the accumulation rates of macro-nutrients such as T-N, P, K, Ca, and Mg, respectively. To achieve the objectives, plants were fed with a nutrient solution with 1.2, 1.8, or $2.4dS{\cdot}m^{-1}$ under three daily photosynthetic photon flux (PPF) of 4.26, 5.51, or $9.75mol{\cdot}m^{-2}{\cdot}d^{-1}$. Both light intensity and EC of nutrient solution significantly influenced the crop growth. The elevation of PPFs resulted in the increase of plant growth. For each light condition, plant growth, such as dry and fresh weight and leaf area, was the highest when the electrical conductivity of nutrient solution was controlled to $2.4dS{\cdot}m^{-1}$. However, growth was acceptable in the EC ranges from 1.8 to $2.4dS{\cdot}m^{-1}$. Both light intensity and EC of nutrient solution significantly influenced the uptake of nutrients in the solution tanks and the accumulation of nutrients in the growing medium. As the EC of nutrient solution was elevated, the absorption rates of $NO_3^-$, $PO_4^{-3}$, $K^+$, and $Mg^{2+}$ by crops and accumulation of those in growing medium increased, but the light intensity did not significantly influence the absorption rates. Based on the above results, the regression models were suggested for anticipating the macro-nutrient accumulations in growing medium.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.12
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• pp.1897-1906
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• 2019

Objective: An experiment was conducted to investigate the effects of dietary non-phytate phosphorus (nPP) deficiency on intestinal pH value, digestive enzyme activity, morphology, nutrient utilization, and gene expression of NaPi-IIb in meat ducks from 1 to 21 d of age. Methods: A total of 525 one-d-old Cherry Valley ducklings were fed diets (with 7 pens of 15 ducklings, or 105 total ducklings, on each diet) with five levels of nPP (0.22%, 0.34%, 0.40%, 0.46%, or 0.58%) for 21 d in a completely randomized design. Five experimental diets contained a constant calcium (Ca) content of approximately 0.9%. Body weight (BW), body weight gain (BWG), feed intake (FI), and feed to gain ratio (F:G) were measured at 14 and 21 d of age. Ducks were sampled for duodenum and jejunum digestion and absorption function on 14 and 21 d. Nutrient utilization was assessed using 25- to 27-d-old ducks. Results: The results showed ducks fed 0.22% nPP had lower (p<0.05) growth performance and nutrient utilization and higher (p<0.05) serum Ca content and alkaline phosphatase (ALP) activity. When dietary nPP levels were increased, BW (d 14 and 21), BWG and FI (all intervals), and the serum phosphorus (P) content linearly and quadratically increased (p<0.05); and the jejunal pH value (d 14), duodenal muscle layer thickness (d 14), excreta dry matter, crude protein, energy, Ca and total P utilization linearly increased (p<0.05); however, the serum ALP activity, jejunal $Na^+-K^+$-ATPase activity, and duodenal NaPi-IIb mRNA level (d 21) linearly decreased (p<0.05). Conclusion: The results indicated that ducks aged from 1 to 21 d fed diets with 0.22% nPP had poor growth performance related to poor intestinal digestion and absorption ability; but when fed diets with 0.40%, 0.46%, and 0.58% nPP, ducks presented a better growth performance, intestinal digestion and absorption function.

• Horticultural Science & Technology
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• v.16 no.3
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• pp.352-354
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• 1998

A soilless culture system with the precise control of nutrient solution was developed and the time changes of ionic contribution to EC reading was analyzed. The measuring device designed was able to wash electrodes cleanly and to measure the pH and EC of nutrient solution stably in the box. The nutrient supply system using metering device was also able to control the EC and pH within ${\pm}0.05mS/cm$ and ${\pm}0.05$, respectively. Under the EC control, activity coefficients of all ions decreased with time as ionic concentrations of $SO_4$, Mg and Ca increased due to the selective nutrient absorption by plants. Time changes of ionic contribution to EC reading could be calculated using equivalent ionic conductivities and activity coefficients obtained by numerical analysis.

• Journal of Bio-Environment Control
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• v.10 no.3
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• pp.133-140
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• 2001

This study was conducted to develop a nutrient uptake model in cucumnber (Cucumis sativus L. cv. Eunsung Backdadagi) plants for prediction of the amount of nutrients in drainage solution in a closed perlite culture system. Electrical conductivity (EC) of the nutrient solution was adjusted to 1.5, 1.8, 2.1, 2.4, and 2.7 dS. $m^{-1}$ . The amount of nutrient solution absorbed in different EC treatments was not different until the mid stage of growth. However, after the mid growth stage, a high EC treatment resulted in less solution absorption. The absorption rates of K, N $O_3$$^{[-10]}$ -N, Mg, and P increased continuously for a whole growing period in all treatments, while those of Ca decreased slightly. For S, the decrease was significant after th mid stage of growth. although the amounts of absorbed inorganic ions in different EC treatments were not significantly different at the first stage of growth, they were significantly different after the mid stage of growth and decreased slightly at the end of growth stage. Models for predicting the amounts of each inorganic ion absorbed were developed by using EC and the amount of nutrient solution absorbed per unit radiation(mg.M $J^{-1}$), which proved to be practical with a positive correlation at 1 percent probability between the developed model and practical values..