• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.81-88
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• 2001

To investigate C and N metabolisms in response to potassium-deficient stress during regrowth of Italian ryegrass(Lolium multiflorum L.), C and N metabolites were analyzed at day 0 (cutting date), 6, 12 and 24 days after defoliation. K-sufficient (control, +K) and K-absent (-K) nutrition solutions were applied from 7 days before defoliation, and continued for one cycle of 24 days-regrowth period. During 24 days of regrowth dry matter of regrowing shoots and remaining tissues were not significantly different between +K and -K treatment. In remaining stubble, all C compounds in both +K and -K treatment largely decreased (69% to 84% of the initial level) during the first 6 days of regrowth, and then rapidly recovered. The decline of soluble sugars and fructan in roots for the first 6 days much less in the -K medium. Amino acids, soluble and insoluble proteins in stubble also feel down during the first 6 days, thereafter actively replenished in both +K and -K treatment. The decline of nitrate in stubble prolonged to 12 days of regrowth. Initial amounts of all N compounds in roots were significantly lower in the -K medium. Higher accumulation of amino acids and soluble protein in roots in the -K medium was observed after 12 days of regrowth. In regrowing shoots, 3 all carbohydrates increased with a very similar pattern for both treatments. Nitrate was not significantly different between two treatments. Depress of soluble protein accumulation in -K medium was noteworthy after 12 days of regrowth. These results indicated that an active utilization of organic reserves occurred to support regrowth even under K deficient condition with a similar extent with K sufficient condition.

• Journal of Korean Society of Forest Science
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• v.88 no.3
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• pp.335-341
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• 1999

To investigate the effect of sulfate deposition un forest tree nutrition, 15 forest stands of Pinus thunbergii were selected throughout Yochon industrial complex, in which is influenced by chronic air pollution. Concentrations of sulfate sulfur, nitrogen, phosphorus, potassium, calcium, and magnesium were analysed fur current and 1-year-old needles of Pinus thunbergii tree. The results obtained were as follows ; 1. Significant higher accumulation of sulfate S, computed with that of unpolluted needles, was observed at all sites, ranging front 0.11% to 0.35% in current needles, and from 0.13% to 0.32% in 1-year-old needles. 2. Ranging from 0.60% to 1.42% in current needles, and from 0.58% to 0.88% 1-year-old needles, respectively, nitrogen concentrations were significantly lower at 7 sites for current needles, and at all sites for 1-year-old needles than at unpolluted site. 3. Phosphorus and potassium levels were significantly lower at very few sites, compared with unpolluted site. 4. Calcium concentrations were significantly lower at 8 sites and 9 sites for current and 1-year old needles than at unpolluted site, ranging from 0.123% to 0.352% and from 0.201% to 0.371% in 1-year old needles, respectively. 5. Ranking from 0.077% to 0.152% in current needles, and from 0.056% to 0.105% in 1-year-old needles, magnesium concentrations were lower at only 2 sites for current needles tut at 12 sites for 1-year-old needles. 6. There were significant declines of concentrations of calcium and magnesium in current needles as sulfate accumulation increased. For 1-year-old needles, there were significant negative correlations-hips between sulfate and nitrogen, potassium, calcium, and magnesium concentration. It is concluded that deposition of sulfuric air pollutant deteriorated nutrients status, resulting in tree decline, in Pinus thunbergii forest in Yochon industrial complex.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.4
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• pp.342-346
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• 1996

Field experiments were conducted to investigate the mode of changes in exchangeable K contents in the soil under the continued(for three years) application of different levels of K fertilizer(KCl) with and without application of conventional compost(CC) and chicken-dung derived compost (CDC) for red pepper cultivation at two field parcels with different exchageable K contents on Gopyong silty loamy soil. The application of KCl at standard rate for red-pepper resulted in the increase in exchangeable K in the soil after each harvest of the crop. while no application of K and the application of KCl at one half of the standard rate tended to lower the exchangeable K in top soil with the cultivation of the crop. The application of compost in addition to KCl ammplified the difference in exchangeable K in the soil before and after the harvest of each crop. An equation could resonably well predict the exchageable K content in top soil after the years of crop cultivation, under different treatments. were developed.