• Korean Journal of Soil Science and Fertilizer
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• 제19권1호
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• pp.63-69
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• 1986

1. Chemical components of fresh tobacco leaves at topping stages were affected variously by fertilizer application level. The more fertilizers were applicated, the higher nitrogen content of leaves was shown regardless of the soil fertility, but phosphorus content was not affected either by phosphorus rate or soil fertility. Potassium content was higher in the leaves grown in fertile soil than infertile at the same application rate. 2. Maturation of tobacco leaves was delayed by applying high level of nitrogen fertilizer, especially in fertile soil. The excessive accumulation of nitrogen in tobacco leaves at later stage of growth resulted in poor quality index for the high content of nicotine and low content of reducing sugar in cured leaves. 3. Nicotine content of cured leaf was increased significantly as nitrogen content increased, regardless of soil fertility, but reducing sugar content was reduced. Nicotine and reducing sugar content of cured leaf were higher in fertile than in infertile soil. 4. Resulting from the facts that nicotine contents were negatively correlated and reducing sugar contents were positively correlated with grading value (Won/Kg), authors suggested that grading index (Won/Kg) of the Office of Monopoly be based on quality index from chemical components of cured leaves.

• Korean Journal of Soil Science and Fertilizer
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• 제17권2호
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• pp.173-178
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• 1984

Correlation study was conducted to establish the optimum test level of soil improvement for good growth of corn from the relationships between the corn yield and soil chemical properties in 16 farmers' demonstration fields. Significant positive correlations between the corn yield and soil chemical properties ; pH, available phosphorus, exchangeable potassium, calcium, magnesium, cation exchange capacity. available silica, and base saturation percentage were showed but organic matter and nitrogen content were not. The proper nutrient contents in soil for expecting corn yield, 1.000kg/10a could be estimated as pH 5.6, available phosphorus 327ppm, exchangeable potassium 0.39me/100g, exchangeable calcium 5.5me/100g, exchangeable magnesium 1.3me/100g, cation exchange capacity 11.5me/100g, available silica 116ppm, base saturation percentage 58 from the relationships between the corn yield and soil chemical properties. Exchangeable aluminium were negatively correlated with not only corn yield but also pH, available phosphorus, exchangeable potassium and exchangeable calcium.

• Korean Journal of Weed Science
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• 제13권2호
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• pp.96-103
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• 1993

The experiments on the ecological characteristics of the suspensible green algae and the algae causing soil-flakes and shier chemical control were conducted in 1992. The unicellular green algae which were dominated by Chlamydomonas sp. largely occurred when phosphorus was applied, but which were reduced by nitrogen application. The filamentous green algae which were dominated by Klebsormidium sp. largely occurred when phosphorus was applied, and which much more increased when nitrogen or potassium was combined with phosphorus. The suspensible green algae which were dominated by Klebsormidium sp. were controlled by 60-70% when simazine 10g ai/10a and propanil 105g ai/10a were applied. The dark blue soil-flakes largely occurred at nitrogen application, and which much more increased when nitrogen was combined with phosphorus. The dark brown soil-flakes largely occurred at phosphorus application, but no more increased even if nitrogen or potassium was combined with phosphorus. The dark blue soil-flakes which were dominated by Oscillatoria sp. much more increased at the temperature conditions of $18^{\circ}C$ compared with $24^{\circ}C$ and $29^{\circ}C$. The applications of bensulfuron/mefenacet/dymron, piperophos/dimethametryn and bensulfuron/dimepiperate controlled 70-90% of the dark blue soil-flakes.

• Journal of Plant Biology
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• 제20권3호
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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.

• Korean Journal of Soil Science and Fertilizer
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• 제49권6호
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• pp.669-676
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• 2016

A field study was conducted to determine the runoff loss of N and P in small scale of red pepper field plots (10% slope), consisting of three different plots with black polyethylene vinyl mulching (mulching), ridge without mulching (ridge), and flat without ridge and mulching (flat). Composted manure and urea as a basal application were applied at rates of $20MT\;ha^{-1}$ and $93kg\;N\;ha^{-1}$, respectively. Urea at $189kg\;N\;ha^{-1}$ and fused phosphate at $67kg\;P_2O_5\;ha^{-1}$ were additionally applied on June 25 with different fertilization methods, broadcast application in flat plot and hole injection in ridge and mulching plots. Plant uptake of N and P was positively correlated with their respective concentrations in surface soil: mulching > ridge > flat plots. The runoff loss by soil erosion was higher in flat plot than ridge and mulching plot with contour line. Nitrate loss by the runoff water had no significant differences among three surface management practices, but the higher average value in ridge and mulching plots than flat plot. Especially, the flat plot had no phosphate loss during summer season. This is probably due to low labile P content in surface soil of flat plot. In the summation of soil and water loss, flat plot was higher in N and P loss than ridge and mulching plot with contour line. Nevertheless, the nitrate and phosphate loss by runoff water could be more important for non-point source management because the water could meet the river easier than eroded soil because of re-deposition around slope land.

• Journal of Forest and Environmental Science
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• 제31권4호
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• pp.280-287
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• 2015

Soil samples were collected from three depths (0-10 cm, 10-40 cm and 40-80 cm) of two forest sites including one plantation dominated by teak with some other minor species and another degraded natural forest in Cox's Bazar, Bangladesh to compare their soil properties. Some vegetation parameters were also studied. For this study $10{\times}10\;m$ and $2{\times}2\;m$ quadrats were used for the tree and undergrowth parameters, respectively. Soil samples were also collected from these quadrats. Between the two forest types, the highest levels of organic carbon, total nitrogen, available phosphorus, exchangeable bases and cation exchange capacity (CEC) were found in soils of the plantation. The soils were acidic in nature and exchangeable Al concentrations were low. Teak dominated forest plantation had higher soil fertility index (SFI) than the degraded natural forest site. Steps for reforestation and appropriate protection are needed to improve the situation.

• Journal of The Korean Society of Grassland and Forage Science
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• 제11권4호
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• pp.230-235
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• 1991

This experiment was carried out to determine the effects of soil phosphorus(P) level on growth environment of annual-and perennial plant. The results obtained are summarized as follow:1. With increasing level of phosphorus fertilizer, plant length of Italian-and perennial ryegrass tended to increase. 2. After the second year, DM yield of perennial ryegrass was significantly higher than that of Italian ryegrass in all treatments. 3. In the difference of P-yield between high P-treatment and nil P-treatment, there was tendency for that of Italian ryegrass to be increased but for perennial ryegrass to be decreased throughout 3 years. 4. The growth of perennial ryegrass compared with Italian ryegrass was tended to profitable in low phosphorus environment than high phosphorus environment.

• Journal of The Korean Society of Agricultural Engineers
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• 제52권5호
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• pp.47-52
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• 2010

The purpose of this study is to investigate characteristics of total phosphorus (TP) and phosphate phosphorous ($PO_4$-P) concentrations in ponded water and redox potential (Eh) in paddy soil during the growing season. The TP and $PO_4$-P concentrations showed twice peak values after basal dressing and tillering fertilization. The ratio of $PO_4$-P to TP showed low values (0.07~0.18), indicating that most of phosphorus is particlulate. The $PO_4$-P concentrations significantly decreased with dissolved oxygen (DO) concentrations. The Eh showed high values (179~636 mV) under non-ponded aerobic condition, but low values (74~112 mV) under ponded anaerobic condition The TP and $PO_4$-P concentrations in ponded water increased shortly after tillering fertilization even if phosphorus was not applied. This may be due to the release of dissolved phosphorus from the bottom sediment and its associated algal and water flea blooms under anaerobic condition. Therefore, proper water management should be needed shortly after tillering fertilization.

• Applied Biological Chemistry
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• 제17권3호
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• pp.193-218
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• 1974

These studies were carried out for the elucidation of liming effect on the growth of rice seedlings and the chemical characteristics of an acid sulphate paddy that shows not only extremely high acidity of soil but also poor growth of rice plants, consequently low yield. Thus the liming effect on the changes of acidity, oxidation-reduction potential, and the contents of iron, aluminium, sulphate, and phosphorus fractions in the soil was investigated under the waterlogging and drying condition. The reclaimable or inhibitory effect of phosphorus, iron and aluminium on the growth of rice seedlings was also investigated under liming. The results are summarized as follows: 1. After liming, the pH of the acid sulphate subsoil decreased again on drying. 2. The oxidation-reduction potential reached a minimum after 5 days of flooding and greatly decreased on liming but increased after drying. 3. The contents of ferrous iron soluble in water-and Morgan's solution reached a maximum after 15 days of flooding and only the content of water soluble ferrous iron was greatly decreased. 4. The content of aluminium soluble in water-and Morgan's solution decreased by flooding and liming, and showed a tendency to increase on drying. 5. In the limed acid sulphate soil, the content of water soluble calcium showed a highly significant negative correlation with the content of sulphate and liming decreased sulphate content in the soil. 6. The contents of total phosphorus was 496.3 ppm in the acid sulphate topsoil and 387.5 ppm in the subsoil. The content of each phosphorus fraction was in the order of Fe-P>Occ. Fe-P>Ca-P>Occ. Al-P>Al-P and Fe-P content in the soil was the highest fraction among them. 7. Lime application increased greatly Ca-P and Al-P, and Occ. Fe-P and Occ. Al-P only slightly, but decreased Fe-P differently in each soil. 8. Effect of phosphorus on the dry matter yield of rice seedlings was great. The optimum amount of phosphorus to produce maximum dry matter yield of rice seedlings appeared to be 6.8% of maximum absorption (absorption coefficient) without liming and 10.0% with liming. 9. In rice seedlings liming increased the content and uptake of calcium and silica but decreased those of iron and aluminium. Phosphorus application increased the content and uptake of phosphorus and decreased iron while the application of iron and aluminium increased their contents and uptake but decreased those of phosphorus. 10. Liming greatly alleviated such toxicity of iron and aluminium. 11. When phosphorus was applied, the dry matter yield of rice seedlings showed highly significant positive correlations with uptake of phosphorus, calcium and silica each. When iron and aluminium were applied, dry matter yields indicated significant positive correlations with the contents or uptake of calcium and silica each, but significant negative correlations with the content or uptake of iron and aluminium. 12. Under the application of phosphorus and lime, dry matter yields showed significant positive correlations with pH and Morgan's extractable calcium each of the soil samples after harvest. Under the application of lime, iron and aluminium, dry matter yields showed significant positive correlations with pH, calcium and silica each, but negative correlations with iron and aluminium contents each of the soil samples after harvest.

• Applied Biological Chemistry
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• 제35권6호
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• pp.449-456
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• 1992

Expermient were conducted to determine the effect of phosphorus stress on bacteroid content and energy status of soybean (Glycine max [L.] Merr.) nodules. Plants inoculated with Bradyrhizobium japonicum MN 110 were grown with P-stressed (0.05 mM-P) and control (1 mM-P) treatment in the greenhouse. Phosphorus stress decreased nodule mass per plant and nodule mass to whole plant mass ratio. Phosphorus concentration in leaf, stem and root tissues were reduced by 75% but in nodule tissue was reduced only by 40% under phosphorus stress during 3 week experimental period. The bacteroid content per unit nodule mass and the distribution of total nitrogen and total phosphorus among the bacteroid and plant cell fractions of nodule were not affected significantly by phosphorus stress. Regardless of phosphorus treatment, 22% of the nitrogen and 27% of the phosphorus in whole nodules were associated with the bacteroid fraction. The ATP and total adenylate concentrations in and energy charge of whole nodule were decreased 77%, 46% and 37%, respectively, by phosphorus stress. The ATP concentration in and energy charge of the host plant cell fraction of nodules were decreased 86% and 59%, respectively, but these parametres in bacteroid in nodules were not affected by phosphorus stress. These results indicated that nodule is a strong phosphorus sink and that nodule growth and development are regulated to maintain a high phosphorus and energy content in bacteroid even when the host plant is subjected to phosphorus deficiency.