• Journal of Nutrition and Health
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• v.8 no.1
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• pp.61-64
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• 1975

This study is designed to find out the mineral contents in Korean foods. In the previous report Part I, Sodium and Potssium contents in vegetables and fruits commonly used in Korean households were analyzed. In this report Part II, Sodium and Potassium contents in cereals are analyzed. Cereals, as a main dish, are one of the most important energy source for Koreans. The data analyzed are shown in Table 1, Table 2, in this report and these will be used as a fundamental guide in planning Sodium-restricted diets in Korea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.4
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• pp.493-501
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• 1995

To investigate an effect of dietary sodium and potassium on blood pressure, 418 adolescents living in Kangwha area were studied. Two measurements were taken on each blood pressure(diastolic, systolic) and the average of the two readings was used in the analysis. Sodium and potassium intake were estimated by the determination of those electrolytes in 24hr urine. Not only dietary factors but also physical growth factors such as weight, height, arm-circumference and skinfold-thickness were induced in the stepwise multiple regression analysis to indentify the relative importance between the factors. The variation of blood pressure both in systolic and diastolic in both sexes was inconsistent with the levels of sodium and potassium intake. The results of multiple regression analysis showed that the physical growth were more influential than nutrient factor. It suggested that hypertension risk factors observed form the adults, may not be identical with that of the growing aged population. After control of the physical growth, there was no significant variation observed by the level of sodium and potassium intake on blood pressure. In summary, the results indicate that growth has been more influential than dietary factor on blood pressure for growing aged population.

• The Korean Journal of Ecology
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• v.19 no.5
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• pp.417-430
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• 1996

This study was conducted to investigate the developmental process of plant community during the secondary succession and the dynamics of soil properties in the burned and unburned areas of Mt. Ch’oly-san. Owing to the forest fire occurred on April, 1989, the red pine(Pinus densiflora) forest and its floor vegetation were burned down. The floristic composition of burned and unburned areas were composed of 53 and 49 species of vascular plants, respectively. The dominant species based on SDR4 of the burned sites were lespedeza cyrtobotrya (89.62), Miscanthus sinensis var. purpurascens (62.50), and Carex humilis (58.73), Quercus serrata (43.33). In contrast, Pinus densiflora (83.56), Lespedeza cyrtobotrya (55.57), Miscanthus sinensis var. purpurascens (51.88) and Carex humilis (50.41) were dominant in the unburned area. The biological spectra showed the $H-D_1-R_5-e$ type in both the burned and unburned areas. The indices of similarity ($CC_S$) between the two areas were 0.74. Degree of succession (DS) was 604 in the burned area and 802 in the unburned area. From these facts, it is assumed that the succession is rapidly progressing because of the recovery of vegetation. The species diversity ($\={H}$) and evenness index(C) in the burned and unburned areas were 0.15 and 0.18, respectively. Red pine tree did not resprout after scorch by the forest fire, but Lespedeza, Quercus, Rhododendron, Albizzia, and Zanthoxylum resprouted from the roots and trunks after the forest fire. It seems that these species are the fire-resistant species. Soil properties such as soil pH, content of organic matter, available phosphous, total nitrogen, tatal carbon, exchangeable potssium, sodium, calcium, and magnesium increased due to forest fire. These results suggest the intensity of forest fire in the study area was relatively weak. Monthly changes of soil properties were of little significance except for some cases.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.4
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• pp.293-296
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• 1990

The effect of wallastonite, potassium chloride and potassium sulphate on the ammonification and nitrification of urea was studied in a non-planted green house experiment, filling with 500g soil in plastic pot and incubating for 17 days. Potassium sulphate gave superior effect on the neutralizing soil acidity of wallastonite than potassium chloride and raised soil pH which promoted ammonification and subsequent nitrification of urea. Less than 20% $NO_3-N$ against the sum of $NH_4-N$ and $NO_3-N$ was accumulated in soils incubated bellow pH 6.0. It seemed that pH 5.2 to 6.0 was the critical range for the nitrification of ammonium, or raising the concentration of ammonia in soils to the toxic level to the nitrification. It appeared that the nitrification could be occuring in low moisture, air dried, conditions of soil.

• Korean Journal of Soil Science and Fertilizer
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• v.5 no.2
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• pp.39-42
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• 1972

A field experiment was conducted in a moderately well drained paddy field doveloped in a narrow strip of a valley in order to observe changes of potassium requirement in paddy production when lime is applied. The results obtained are as follows; 1. The response of paddy to potassium (K) and lime (L) is represented mathematically as follow; $Y=462.78+11.582K-0.058L-0.768K^2-0.000015L^2+0.2204KL$. It is considered that the increase of potassium reqirement when slaked lime is applied, is partially due to the increased growth of plant accomplished by the improvement of soil conditions such as the reduction of respiration inhibitors and cationic balance in soil solution. 2. An economic analysis of the use of potassium and slaked lime applying the costs, 80 won per kg of paddy, 19 won per kg of potassium and 4 won per kg of slaked lime to the response function above, showed that the slaked lime without potssium brought a large loss, whereas the use of the lime together with potassium increased the profit remarkably. The profit increased when 10kg of potassium per 10 a is applied in addition to 200kg slaked limn, per 10kg is amounted 4,685 won. 3. A linear relationship between the economic optimum dose of potassium (y) and the amount of slaked lime (x) in paddy production, is obtained as follow; $$y=7.48+\frac{2.77}{200}x$$ It is, however, considered that the amount of potassium to he used might differ according to the soil conditions such as the potassium content and cation exchange capicity of the soil.