• Journal of Plant Biology
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• v.20 no.3
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• pp.109-118
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• 1977

Seasonal distribution of N, P and K contents and their cycling were studied in Korean oak (Quercus acutissima) and Korean alder (Alnus sibirica) stands in central part of Korean peninsula. The amounts of three minerals were high in young leaves but gradually decreased with the process of leaf development in both stands. The amounts of minerals in the branches, trunks and roots were decreased in summer, however, they increased again in autumn. Seansonal changes of these minerals were not significant in the two stands. The amounts of phosphorus and potassium in plant and soil were higher in the oak stand than the alder one, but those of nitrogen were reversed. The amounts of minerals absorbed during one year were greater in the oak stand than in the alder one, but those returned into soil through mineralization of litter were less in the former than in the latter. The nutrient requirements of the oak stand were greater than the alders, but the cycling rate, the ratio of the amount of minerals absorbed to returned, was opposite.

• 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..

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.4
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• pp.225-232
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• 2003

Nutrients and water absorption by Citrus unshiu Marc. cv. Miyagawa Wase were examined using spray type of out-door hydroponics system. Three different concentration levels of nutrient solution were treated to citrus trees to examine nutrient uptake. To do so, concentration and the volume change of nutrient solution was measured for each treatment. By weighing the volume of solution and citrus trees, amounts of water uptake and fresh weight increase were observed periodically. Water uptake by trees increased as tree grew and time elapsed, but was lower at high level of nutrient concentration than the rest, due partly to the reduction in hydraulic conductance and to the sustained high salt concentration. Rapid increase in fresh weight and nutrient uptake occurred from May to July and from August to September. The amounts of nutrient uptake were significantly different among nutrient levels: the higher concentration, the greater uptake by citrus tree. The absorbed amounts of $NO_3$, K and Ca were much higher than those of $NH_4$, S, P, Mg, and Fe. Most mineral contents in leaves were proportional to the concentration of supplied nutrient solutions. From the results of nutrient absorption and contents in leaves at different levels of nutrient solutions, the composition of major elements for citrus nutrient solution can be modified as follows: 27.1, 16.5, 66.0, 80.0, and $24.0mg\;L^{-1}$ for N, P, K, Ca, and Mg, respectively.

• The Korean Journal of Ecology
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• v.20 no.1
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• pp.27-33
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• 1997

Species composition and the amount of nutrients absorbed by regenerating plants on a pine forest in the immediate postfire year were compared with those in an unburned pine forest in Kosung, Kangwon Province. Pteridium aquilinum var. latiusculum, Cyperus amuricus, Lespedeza biolor, Quercus serrata, Lysimachia clethroides were the most abundant species in burned area. In unburned area. Quercus mongolica, Rhododendron mucronulatum, Carex humilis, Rhododendron schlippenbachii, Spodiopogon sibiricus were the most abundant species. Standing biomass of understory vegetation in burned and unburned area was 170.2 g $D.W/m^2$ and 171.3g $D.W/m^2$, respectively. Nutrient concentrations of plants in burned area, especially for phosphorus and potassium, were higher than those in unburned area. The amounts of nutrients absorbed by understory plants in burned and unburned area were 37.4 and 33.6 kg/ha for N, 0.36 and 0.19 kg/ha for P, 30.6 and 18.8 kg/ha for K, 8.5 and 7.8 kg/ha Ca, 5.2 and 5.7 kg/ha for Mg, respectively. This suggests that regenerating vegetation can hold the significant amount of nutrients, although there may be considerable losses of nutrients from ecosystem after fire.

• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.1-8
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• 2012

BACKGROUND: Organic fertilizers in watermelon cultivation are widely used to supply nutrient and organic matter. This study was conducted to investigate the effects of application rate of organic fertilizer on the watermelon growth and soil chemical properties in greenhouse METHODS AND RESULTS: The organic fertilizers used in this experiment were mixed expeller cake (MEC) and mixed organic fertilizer (MOF). The treatments were conducted with 4 levels (1.0 N, 0.7 N, 0.5 N and 0.3 N) on the basis of soil testing nitrogen fertilization (STNF) using MEC or MOF as the basal dressing, and using chemical fertilizers (CF) as the additional dressing on the rest of STNF. These fertilizations were compared to CF 1.0 N (0.3 N as the basal and 0.7 N as the additional dressing) and non fertilization (NF). The leaf area of watermelon in treatment 0.5 N and 0.3 N using MEC or MOF was similar to CF treatment. The absorbed nutrient amounts by leaf, weight and sugar contents of fruit in the 0.5 N and 0.3 N treatments were higher than other treatments. In 0.5 N and 0.3 N treatments using MEC or MOF on the basis of STNF, soil chemical properties such as electrical conductivity (EC), available $P_2O_5$ and exchangeable K concentrations after experiment showed tendency to decreasing or similar level before experiment. CONCLUSION(s): These results suggest that the MEC or MOF application as the basal dressing at the 30~50% level of STNF and CF application as the additional dressing on the rest of STNF be best to maintain adequate nutrient of soil and to increase marketable yield for watermelon.

• The Korean Journal of Ecology
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• v.15 no.1
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• pp.35-46
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• 1992

To elucidate nutrient cyclings such as nitrogen, phosphorus and potassium in mongolian oak(quercus mongolica) forest, nutrient elements of precipitation, throughfall, outflow, soil, various plant organ and litter were determined at mt.nambyeongsan, pyeongchang-gun, gangwon province in central part of korean peninsula. Annual precipitation input, throughfall and outflow of nutrientswere 10.3, 8.6 and 4.2 kg/ha for the N, 0.11, 0.24 and 0.02 kg/ha for the Pand 1.3, 10.9 and 1.2 kg/ha for the K, respectively. Inseasonal changes of nutrient concentrations, N, P and Kconcentrations which were rich in young leaves decreased steadily until autumn and decreased abruptly during autumnal yellowing. The standing N, P and K concent were 565, 37 and 257 kg/ha for standing phytomass of overstory, 33, 3 and 18 kg/ha for understory, 132, 3.6 and 14 kg/ha for litter on ground including deadwood and 20, 752, 14 and 420 kg/ha for the soil, respectively. The amounts of annual uptake, reture and retain were 174.2, 57.2, 117.2 kg/ha for the N, 9.9, 3.5, 6.4 kg/ha for the P and 73.2, 30.3, 42.9 kg/ha for the K, respectively. Reabsorption efficiency, ratio of the nutrient amount reabsorbed into woody organs to that in the mature leaves before shedding, was 71%(or 99.8 kg/ha in the amount), 69%(or 5.1 kg/ha) and 57%(or 33.1% kg/ha) and recycling coeffciently made with which the large amount of nutrients is absorbed through roots during growing season(UPTAKE) and reasorbed from the leaves before shedding(RETAIN) but the small amount of nutrients is returned through litterfall(RETURN).

• Journal of Nutrition and Health
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• v.18 no.3
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• pp.217-224
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• 1985

The purpose of this study is to discribe the nutritional status between female collegians on normal diet and lacto-ovo-vegetarian in the child bearing age. Physical examination, hematological parameters(hemoglobin, hematocrit, serum iron, serum albumin)and nutrient intake by dietary survey were carried out on each subject. Serum zinc, iron and copper concentrations were also determined. The results are summarized as follows : 1) Students on normal diet had higher values than lacto-ovo-vegetarian students in the height, weight, and skinfold thickness. 2) Hemoglobin, hematocrit, serum albumin values of the two groups showed no difference. But students on normal diet were higher in the serum irom and copper values than lacto-ovo-vegetarian students. 3) Serum zinc values differed significantly between the vegetarians and non vegetarians (Vegetarians') > non vegetarians') 4) On the nutrient intake of two groups, students on normal diet were higher than lacto-ovo-vegetarian students in the protein but students on normal diet were lower than lacto-ovo-vegetarian students in iron, vitamin A, $vitamin\;B_{2}$, vitamin C and crude fiber. 5) Intakes of calories and protein in the two groups were lower than RDA but Ca, vitamin A, $vitamin\;B_{1}$, $vitamin\;B_{2}$ niacin and vitamin C intakes of the two groups was higher than RDA. 6) Amounts of iron absorbed showed no difference in the two groups. But iron absorption rate was higher in students on normal diet than lacto-ovo-vegetarian students.

• Korean Journal of Environmental Agriculture
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• v.41 no.3
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• pp.191-198
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• 2022

BACKGROUND: Plants can be grown using a culture medium without soil using a hydroponic system. Crop production by the hydroponic system is likely to increase as a means of solving various problems in the agricultural sector such as aging of rural population and climate change. Different water sources can be used to prepare the culture medium used in the hydroponic system. Therefore, it is necessary to study the effect of different water sources on crop production by the hydroponic system in order to explore the applicability of various water resources. METHODS AND RESULTS: Lettuce was cultivated by the hydroponic system and three different water sources [tap water (TW), bottled water (BW), and groundwater (GW)] were used to compare the effect of water sources on lettuce growth. The three kinds of waters with a nutrient solution (TW-M, BW-M, GW-M) were also used as the media. After the six-week growth period, the lettuce length and weight, the number of leaves, and the contents of chlorophylls and polyphenols were compared among the different media used. The lettuces did not grow in the waters without the nutrient solution. In the media, the lettuce growth and the contents of chlorophylls were affected by the different water sources used to prepare the media, while the contents of polyphenols were not affected. The absorbed amounts of ions by lettuces, especially Ca and Zn ions, and the dry weight of the harvested lettuces showed a strong positive correlation. CONCLUSION(S): Overall, this study shows that different water sources used for growing lettuce in a hydroponic system can affect lettuce growth. Further studies on the enhancement of crop qualities using different water sources may be required in future studies.

• Journal of Wetlands Research
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• v.1 no.1
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• pp.29-44
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• 1999

Vegetation structure and distribution of the vascular hydrophytes and hygrophytes, and the growth pattern, standing crop and amounts of nutrient uptake by Salix species were investigated in the upper stream wetlands of the Namgang-Dam, Chinju-city, Gyeongsangnam-do, Korea from April to November in 1997. The flora was composed of 43 hydrophytes and 241 hygrophytes, or total 284 vascular plants. The life forms of the hydrophytes were classified as 27 kinds of emergent plants, 4 floating-leaved plants, 3 free-floating plants, and 9 submersed plants. In the herb layer, the dominant species was Persicaria hyciropiper, and the ranges of the species diversity indices (H'), equitabilities, (J') and community similarity indices (CCs) were 1.59~1.89, 0.87~0.96, and 0.35~0.83, respectively. In the shrub and subtree layers, 17 kinds of Salix species were supposed to the pioneer plants at the early stage of the succession. The number of branches per main stem of Salix species was 5.0. The DBH class-frequency histograms of Salix species were the reverse J type, and the natural regeneration of the Salix community was expected. Basal area of Salix species per square meter was $24.87cm^2$. Volume of Salix species per square meter was $12,008cm^3$ and total phytomass of the Salix species was estimated as 12,894 ton. Biomass distribution of Salix species in the stem, the branch and twig, and the leaf was 64.1%, 28.1%, and 7.8%, respectively. The amounts of nitrogen and phosphorus absorbed by Salix species were 68,022 and 19,823 kg. It was recommended that application and conservation of the wetland and other counterplans are indispensable to reduce the adverse effects of water pollution and to preserve the wetland ecosystem.

• Korean Journal of Environmental Agriculture
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• v.17 no.2
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• pp.145-149
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• 1998

To find out the effect of water hyacinth(Eichhornia crassipes Solms-Laub) on the control of eutrofication and plant damage with irrigation water contamination, its ability to remove the nutrients such as nitrogen and phosphrus was studied. The overall results are summarized as follow. 1. It was possible to cultivate water hyacinth for 4 month from June to the middle of October in Suwon. 2. The number of plant was increased from 1,320 to 50,600 for 4 months, and total amounts of N, P, K removed from Seo-Ho by water hyacinth were 78.3, 64.2 and 152.4 kg/10a, respectively. 3. EC and $NH_4-N$ contents were lower at water hyacinth treatment than non-treatment and monthly variation of those contents were decreased until August. 4. With the cultivation of water hyacinth in animal waste water in vinyl plastic house, pH, EC, COD and concentrations of $NH_4-N$ and $PO_4-P$ in the water were drastically decreased. 5. Nitrogen contents absorbed from waste water existed in the order of leaf > stem > root but those of phosphorus root > stem > leaf.