• Korean Journal of Soil Science and Fertilizer
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• v.27 no.3
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• pp.179-188
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• 1994

This study was conducted to investigate the distribution of potassium fractions and to establish the soil chemical indices for assessing potassium availability in upland soil. Soil samples were collected from 66 vegetable crop fields of Chungbuk Jungweon, Jeonbuk Imsil and Kyengbuk Euiseong and these samples were analyzed water soluble(W. S. -K), exchangeable(Exch. -K) and nonexchangeable potassium(Nonex. -K). The distribution of potassium fractions was examined for soils having different physico-chemical properties and compared with the soil parameters related to the potassium availability. 1. The distribution ranges of W.S.-K, Exch.-K and Nonex.-K were 0.07~1.42, 0.27~2.30, and 0.84~4.74me/100g, and average contents of relevent fractions were 0.40, 1.03 and 2.37me/100g respectively. 2. Contents of W.S.-K and Exch.-K were decreased with increasing soil pH, CEC, Exch. Ca and Exch. Mg contents but Nonex. -K showed a low correlationship with these factors. 3. Exch.-K content slightly inereased with increasing clay content, while W.S.-K and Nonex. -K contents were grandually decreased with clay contents. 4. The relationship between W.S.-K and Exch.-K was significant and W.S.-K was released from soil at 0.23me/100g content of Exch.-K 5. Contents of W.S-K and Exch.-K showed high correlationship with soil chemical parameters such as ratio of exchangeable cations(K/Ca+Mg), ratio of exchangeable cation equivalent[$K/{\sqrt{Ca+Mg}}:(me/100g)^{1/2}$], potassium exchangeable free energy(${\Delta}F=RT$ 1n $K/{\sqrt{Ca+Mg}}$ : calories/mole) and saturation percentage of potassium($Exch.K/CEC{\times}100$), and these factors were considered to be good parameters for assessing soil potassium availability.

• 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.

• Korean Journal of Organic Agriculture
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• v.21 no.2
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• pp.283-294
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• 2013

Root-rot disease is a serious problem in ginger cultivation fields and it reduces the quality and productivity of ginger. This study was conducted to investigate the effects of different soil physical and chemical properties on the changes of ginger growth. As comparing the selected soil chemical properties after harvesting the ginger plants with those before planting them, the contents of total nitrogen and exchangeable $Mg^{2+}$ increased, whereas electrical conductivity (EC) and exchangeable $K^+$ content decreased. Potassium (K) concentrations in ginger plant were markedly higher in both its shoot and root parts ranging from 63.9 to $72.3g\;kg^{-1}$ and from 27.6 to $37.3g\;kg^{-1}$, respectively, which might be related to the decrease of exchangeable $K^+$ content in soils. Incidence rate of ginger root-rot disease in the plots ranges between 26.7% and 88.1%. It was higher in low elevation plots with clay loam soils than in high elevation plots. In addition, the incidence of the disease increased as affected by high temperature and humid condition during the growth and maturity stages of ginger. Therefore, soil texture, field slop, and drainage system as well as chemical properties should be considered to cultivate ginger plant.

• Korean Journal of Environmental Agriculture
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• v.6 no.2
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• pp.31-38
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• 1987

The present study was carried out to determine the effect of the physical, chemical and mineralogical properties of paddy soil on the adsorption and desorption of $Sr^{90}$ from absorbed soils. The results obtained were as follows: 1. Most of the adsorbed $Sr^{90}$ was exchangeable and water soluble. $Sr^{90}$ extracted by ammonium acetate was very high compared to the water soluble fractions, and the ammount decreased with the increase of calcium application, but increased proportionally with the increase of $Sr^{90}$ treatment. 2. The distribution of $Sr^{90}$ in paddy soil depend on the soil type. Average-distribution rates of water soluble, exchangeable and non-exchangeable fractions of $Sr^{90}$ in the soils were 28.6%, 59.3% and 12.1% respectively. 3. The non-exchangeable from of $Sr^{90}$ was high in the soils of high illite and low vermiculite content. 4. The desorption of $Sr^{90}$ from adsorbed soils decreased with the increase of pH and ex-cations of the soils, but increased with the amount of organic matter and clay content in the soil.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.189-201
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• 1977

Some of basic aspects of soil potassium with special reference to soil physical properties were discussed. Data in the Official Soil Series Description(Korea) was analyzed according to soil type, land form, and soil texture to find soil potassium status which may explain different response to potassium application. Exchangeable potassium contents decreased with soil depth irrespective of soil type, land form and soil texture. Change in degree of potassium saturation within soil profile was not so clear as exchangeable potassium but the degree of potassium saturation of A horizon was highest among soil horizon. Soils of terrace and mountain foot slope showed high values both in exchangeable potassium and degree of potassium sauration and only these two soils were classified as soils having exchangeable potassium higher than 0.3 meq per 100g of soil and degree of potassium saturation higher than 5.0%. Exchangeable potassium of fine loamy and fine clayey soils is higher than 0.3 meq per 100g of soil but degree of potassium saturation is lower than 4.0%. Degree of potassium saturation of sandy soils exceeds 5.0% but exchangeable potassium is very low. Soils of rolling, hilly, unmatured and alpine land soils have lower exchangeable potassium and show lower degree of potassium saturation. The highest distribution of exchangeable potassium content irrespective of soil horizons was shown in the range of 0.1-0.2 meq per 100g of soil. The highest distribution of degree of potassium saturation was in the range of 2.0-3.0% in A horizon and 1.0-2.0% in B and C horizons. Of the soil series concerned in this analysis, 27.3% in A horizon, 11.1% in B horizon and 4.0% in C horizon had exchangeable potassium higher than 0.3 meq per 100g of soil and 18.0% in A horizon, 6.3% in B horizon, and 4.1% in C horizon showed degree of potassium saturation higher than 5.0%. The low response of potassium application only to soils in terrace and mountain foot slope may be resulted from the high exchangeable potassium content and high degree of potassium saturation. It is concluded that a great response of potassium application to soils is expected especially in dry season.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.230-235
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• 1993

This study was carried out to investigate the supplying capacity of various forms(Water soluble, exchangeable, and available) of potassium in soils of different site quality by using surface soils from the Japanese cedar(Cryptomeria japonica) forests in Cheju island. Major results can be summerized as follows. Using continuous leaching methods with 0.01N-HCl, accumulated amounts of available potassium from surface soils of site upper and site low were about 0.6me/100g and 0.4me/100g, respectively. The release ratio of available potassium in the first $1{\ell}$ leaching of 0.01N-HCl to the total available potassium leached with $6{\ell}$ of 0.01N-HCl was over 80% for both sites, and this suggester that surface soil of both sites had the weak potassium adsorptivity as the typical volcanic ash soil. The ratio of the exchangeable potassium to the water soluble potassium was 1 : 1 for both sites. The ratio of the exchangeable potassium to the available potassium was 1 : 1 for the site low but the smaller ratio value for the site upper, indicating that the potassium supplying power of the site upper was greater than that of the site low. Available potassium was highly correlated with exchangeable Ca($0.83^{**}$) and Mg($0.84^{**}$).

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.3
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• pp.185-191
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• 1974

Incubation and pot studies were conducted with upland soils for a study on determination of the lime requirement based on exchangeable alumium content. The results obtained are as follows; 1. Results of chemical analysis of upland soils show that pH varies from 5.0 to 5.4, and exchangeable Al moves with the range of 1.3-3.0m.e/100gr. Exchangeable Al decreases with years of cultivation. 2. Incubation studies shows that on acid mineral soils almost all exchangeable Al, on average 95% was neutralized with the lime to neutralized 100% exchangeable Al. On volcanic ash soil, however, only 65.5% was neutralized with the lime estimated to neutralize the equivalent of 200% exchangeable Al. The latter has required more lime. 3. The pH of mineral soils is on the average increased from an initial 5.2 to 6.3 when 95% of exchangeable Al is neutralized, whereas that on volcanic ash soil is increased from an initial 5.3 to 5.5 only when lime is applied at rate to neutralize the equivalent of 200% exchangeable Al. 4. A high correlation coefficient (r=0.99) was obtained between exchangeable Al and exchangeable acidity. This indicates that exchangeable acidity is primarly a result of exchangeable Al. 5. In pot experiments with soybean cultivated on one of the hill land soils (Songjoong soil) the application of fused phosphate and triple superphosphate based on a 5% saturation rate ($P_2O_5$ 32.1 kg/10a) showed that the liming factor for calculation of the optimum lime requirements based on exchangeable acidity was 0.594 for fuses phosphate or 1.132 for tripple superphosphate, and optimum pH is approximately 6.0 and optimum neutralization rate of exchangeable Al is 80-90%.

• Korean Journal of Plant Resources
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• v.35 no.5
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• pp.675-685
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• 2022

A comparative analysis was performed on the soil chemical properties of greenhouse or open field where flower crops were grown from 2018 to 2020. The pH of greenhouse soils was kept slightly higher than the optimum range suggested by Rural Development Administration and that of open field soils was maintained within the optimum range for three years. The contents of organic matter (OM) were within the optimum range without significant change every year in both soils. Available phosphate (Av. P₂O₅) of greenhouse soils was the highest at 560 mg/kg in 2018, but it decreased every year and fell within the appropriate range in 2020. The concentration of Av. P₂O₅ in open field soils have fluctuated for three years, not showing a significant difference. Electrical conductivity (EC) of greenhouse soils was higher every year than the standard, 2.0 dS/m, but EC of open field soils remained below the standard. The contents of exchangeable cations were higher than the standard, showing significant differences among the years in greenhouse soils. In open field soils, other cations except exchangeable K⁺ were maintained higher than the optimal level and only Ca²⁺ showed a significant difference among the years. In Pearson correlation matrices, the value of exchangeable Ca²⁺ had a significantly positive correlation with exchangeable Mg²⁺ content at both greenhouse and open field soils. Based on principal component analysis, the soils of greenhouse were distributed within the range of high concentrations of Av. P₂O₅, EC and exchangeable cations, while the soils of open field were characterized by low contents of OM and exchangeable cations. Therefore, it is essential to lower the concentration of exchangeable cations in greenhouse soils. It is common for the soils of open field to have a low OM content, so that organic fertilizers should be more actively applied to the soils in open field.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.3
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• pp.177-182
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• 1991

This study was carried out to clarify the effects of grassland afforestation on some chemical properties of the Japanese ceder(Cryptomeria japonica) forest soil in Cheju Island. The following results were obtained in this study ; 1. T-C, T-N, exch. cations and base saturation in the surface soil(0~10cm) decreased sharply from planting to crown closure. However, after crown closure, exch. Ca and Mg increased considerably. On the other hand, there were no definit changes below surface soil. 2. In vertical distribution of chemical properties, T-C, T-N, exchangeable acidity and exch. cations decreased with soil depth. Especially, exch. Ca and Mg of surface soil in closed stand show a higher value than that in open stand, but there were no variation below surface soil. 3. In closed stand, the amounts of exch. Ca, Mg and K were 1.8 times, 1.6 times and 1.5 times greater than those in open stand. There was no significant difference between open and closed stand in T-C and T-N. 4. The ratios of the amounts of nutrients in surface soil to those in mineral horizons(ha, 50cm) between the open and closed stand showed 30% and 50% for exch. Ca, 30% and 40% for exch. Mg, 38% and 38% for exch. K, respectively.

• Korean Journal of Environment and Ecology
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• v.29 no.5
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• pp.777-784
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• 2015

This study verified the correlations between vegetation factors, such as the number of individual species and species diversity, and soil factors in Chamaecyparis obtusa (CO) stands in Jeollanam-do. Also, the site environmental factors that affect the annual growth of CO ring width were analyzed. Positive correlations were found between the species diversity index and Cation Exchange Capacity (CEC), available phosphate, and exchangeable $K^+$ (P<0.01). In addition, strong positive correlations were also found between the number of species that appeared in the study site and CEC, available phosphorus, exchangeable $K^+$ and exchangeable $Mg^{2+}$ (P<0.01). Tree ring growth showed strong correlations with the nutrient holding capacity and fertility of soil, including available phosphate, exchangeable $K^+$, CEC, and electrical conductivity (P<0.01). The explanatory variables of tree ring growth in CO were composed of exchangeable $K^+$, organic matter content, and soil pH. The regression model had a high level of explanatory power, 74.4%. In this model, the annual growth of CO ring width increased when exchangeable $K^+$ and organic matter content were higher but decreased when soil pH was lower. According to the analysis, it is found that the annual growth of CO ring width was significantly affected by soil fertility, including available phosphate, exchangeable $K^+$, CEC, and electrical conductivity. In addition, the soil fertility of CO stands seems to be significantly affected by the supply of fallen leaves from the understory vegetation of CO.