• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.444-450
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• 2012

The physical and chemical properties of soil in the Mangyeong and Dongjin river basin had been investigated in order to establish the most optimum soil improvement plan on the reclaimed land. The total soil area by reclamation in Saemangeum basin is 113,971 ha. The classification by the distribution of soil series and soil texture is as following. 13 soil series including Chonnam, Buyong and Chonbuk series are period-unknown areas. Regarding the soil texture, they are fine silty ~ clayey very fine. From 1920s to 1960s, Mangyeong, Gwanghwal and Chonbuk series had coarse silty textured soil. After the 1970s, Mangyeong, Gwanghwal, Munpo, Yeompo, Poseung, Gapo and Hasa series have more sandy soil ~ moderately coarse loamy textured soil. Regarding the chemical properties, the concentrations of EC, Exch. $K^+$, $Mg^{2+}$, $Na^+$ and pH are high regardless of the time of reclamation. On the other hand, organic matter (OM) of top soil were 3.3~16.1 g $kg^{-1}$. The organic matter contents were very low though the soil had been farmed for a long time. Furthermore, the deep soil had almost no organic matter with 5.6~1.1 g $kg^{-1}$. The reason is believed that there had not been any movement of OM and clay because pressure or induced pans had been formed by large agricultural machineries and poor vertical drain. Regarding the forming of illuvial horizon (B layer) which tells the development extent of soil, only in the Hwapo reclaimed area where rice had been cultivated for past 90 years, Fe and Mn from top soil are deposited at underground 20~30 cm with 7~8 cm thickness by the movement of clay. It is believed that it had been possible because the earthiness is silty clay loam soil with relatively high content of clay. The soils are soil with concern of damage from sea water, soil on flimsy ground and sandy soil. Therefore, soil improvement for stable crop production can be expected; if the water table would be lowered by subsurface drainage, the water permeability would be enhanced by gypsum and organic matter, and the sandy soil would be replaced by red soil with high content of clay.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.557-575
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• 2020

Plasma blasting which is generated by high voltage arc discharge of electricity is applied to soil mass to improve permeability of soil and cleaning efficiency of oil contamination. A new high voltage generator was manufactured and three types of soil including silty sand, silty sand mixed with lime and silty sand mixed with cement were prepared. Small and large soil columns were produced using these types of soil and plasma blasting was performed within soil columns to investigate the variation of soil volume penetrated by fluid and permeability. Soil volume penetrated by fluid increased by 11~71% when plasma blasting was applied in soil. Although plasma blasting with low electricity voltage induced horizontal fracture and fluid penetrated along this weak plane, plasma blasting with high voltage induced spherical penetration of fluid. Plasma blasting increased the permeability of soil. Permeabilty of soils mixed with lime and cement increased by 450~1,052% with plasma blasting. Permeability of soil increased as discharge voltage increased when plasma blasing was applied once. However, several blastings with the same discharge voltage increase or decrease permeability of soil. Oil contaminated soil was prepared by adding diesel into soil artificially and plasma blasting was performed in these oil contaminated soil. Cleaning efficiency increased by average of 393% for soil located nearby the blasting and by average of 239% for soil located far from the blasting. Cleaning efficiency did not show any correlation with discharge voltage. All these results indicated that plasma blasting might be used for in-situ cleaning of oil contaminated soil because plasma blasting increased permeability of soil and cleaning efficiency.

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.1-7
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• 2007

Slug/bail tests were conducted in sand layer (sbt-1 well), silty sand layer (sbt-2 well), and mixed sand and silty sand layer (sbt-3 well). Hydraulic conductivity and specific storage coefficient were estimated through slug/bail tests. Pore volumes of groundwater level drawdown zone for bail test were estimated by using hydraulic conductivity and specific storage coefficient. KGS model was most suitable interpretation method of slug/bail tests. Average hydraulic conductivity for slug/bail tests were estimated to be $6.65{\times}10^{-5}$ m/sec in sbt-1 well, $6.33{\times}10^{-6}$ m/sec in sbt-2 well, and $3.72{\times}10^{-5}$ m/sec in sbt-3 well. Average specific storage coefficient for slug/bail tests were estimated to be 0.0225 in sbt-1 well, 0.0177 in sbt-2 well, and 0.0259 in sbt-3 well. Dimensionless time and dimensionless wellbore storage were estimated by use of transmissivity, storativity, test time, and specification of test wells. And, dimensionless drawdown were selected by parameter ${\alpha}\;and\;{\beta}$ parameter from Cooper et al. (1967). Radius of influence were estimated by estimated dimensionless time, dimensionless wellbore storage, and dimensionless drawdown. The average radius of influnce for slug/bail tests were estimated to be 1.377 m in sbt-1 well, 1.253 m in sbt-2 well, and 1.558 m in sbt-3 well. Pore volume at groundwater level drawdown zone by dummy withdrawal for bail tests were estimated to be $145,636cm^3$ in sbt-1 well, $71,561cm^3$ in sbt-2 well, and $100,418cm^3$ in sbt-3 well. Pore volume excepted well volume at groundwater level drawdown zone by dummy withdrawal for bail tests were estimated to be $145,410cm^3$ in sbt-1 well, $71,353cm^3$ in sbt-2 well, and $100,192cm^3$ in sbt-3 well.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.2
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• pp.53-60
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• 1975

Vegetables are often cultivated continuously year round in a vinyl house with heavy application of fertlilizers, which leads to accumulation of salts in the soil. A field experiment was conducted to investigate the effect of watering on salt eluviation from the soil, and on the yield of tomatoes in the vinyl house. The results were summarized as the followings: The salt eluviation increased with the amount of water applied. The efficiency of the salt eluviation was greater for the silty clay loam soil than the sandy loam soil. With a given amount of water, the efficiency increased with frequency of watering. The yield of tomatoes was increased by watering. However, the yield was not necessarily correlated to the amount of salt leached. Increase in yield of tomatoes by watering was in order of the treatment, 100mm (50-50), 150mm (50-50-50 or 100-50), and 200mm (100-100) of water for both soils. Relationship between the yield of tomatoes and electrical conductibity of the soil (1 : 5 extract) was described by the following regression equation : $Y=1,739.0+437.5X-290.5X^2$ $(R=0.632^{**})$ for sandy loam soil, and $Y=1.542.2+454.1X-275.0X^2$ $(R=0.622^{**})$ for silty clay loam soil. The yield of tomatoes in salt accumulated soil was inversely correlated to extractable sodium and potassium, and to the ratio of extractable sodium to calcium (Na/Ca), while the yield was not correlated to extractable calcium and magnesium.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.2
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• pp.115-121
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• 1987

A pot experiment was conducted to investigate the influence of Ca and Mg saturation ratios of soil on the uptake of Ca, Mg and K by rice plant. A silty loam soil was treated with $CaCl_2$ and $MgCl_2$ to obtain different degrees of Ca and Mg saturation. The studied ranges of Ca and Mg saturation ratios were 81:19, 70:30, 52:48, 55:45, and 31:69 in terms of the ratio of exchangeable Ca and Mg. Two levels of K application (90kg/ha, and 180kg/10a as $K_2O$) were also included in this study. The significant observation were summarized as follows. 1. When the Ca saturation of soil was dominant over Mg, the soil solution contained more Ca than Mg and vice versa. These led to the higher uptake of Ca by rice plant in Ca dominant soils and higher uptake of Mg in Mg dominant soils. 2. When the Ca and Mg saturation ratio was about equal, more Mg was released to soil solution leading to higher concentration of Mg in rice plant compare to that of Ca. 3. A trend was observed that the concentration of K in soil solution was lower in Mg dominant soils than in Ca dominant soils. This also resulted in the depressed uptake of K by rice plant under Mg dominant system when compare to Ca dominant system. 4. The increase application of K led to the increase in relative concentration of K to (Ca+Mg+K), and to the depression of divalent uptake by rice plant. However, it was observed that the degree of depression in uptake divalent by K application was more sensitive in case of Mg than that of Ca. 5. When viewed from grain yield of rice, it is pointed out that the optimum range of Ca to Mg ratio in soil may fall in the vicinity of 7:3. 6. Although K uptake by rice plant was influenced by the term of $AK^+/{\sqrt{A(Ca^{{+}{+}}+Mg^{{+}{+}})$ in soil solution, $AK^+$ itself was affected by the ratios of Ca:Mg in soil, as it were $AK^+$ value was decreased in Mg dominant soil than in Ca.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.5
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• pp.304-314
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• 2004

The objective of this study was to investigate the effect of organic materials (compost, straw, green manure, pig manure, seed production oil cake, and industrial by products including municipal sewage sludge, industrial sewage sludge, leather processing sludge, and alcohol fermentation processing sludge) on physical properties of soils in seven paddy and four upland fields with differential soil textures, sandy loam, loam, or clay loam, etc. The investigated physical parameters were bulk density (BD), air permeability (AP), macroporosity, hardness, shear resistance, frictional resistance, water stability aggregate (WSA), and Middleton's dispersion ratio. Except for coarse sandy loam field with weak structure, a decrease in BD and shear resistance, and an increase in macroporosity and AP in plots with applying organic materials compared to plots without applying organic materials appeared. In upland fields, the positive effect of organic materials on WSA, BD, and air permeability was higher than in paddy fields. The combined plot of NPK and compost had lower BD, hardness, and shear resistance, and higher macroporosity and WSA than plot with compost. Green manure had higher positive effect on physical properties of soils compared to other organic materials and the extent of positive effect had no significant correlation with soil organic matter content. Of industrial byproducts applied in coarse sandy loam soil under upland condition, municipal sewage sludge and pig manure compost had higher effect on increase of WSA than leather processing sludge and alcohol fermentation processing sludge. Unlike WSA, there were no significant differences between industrial byproduct types in other physical properties. in silty clay loam soil under the upland condition, straw had more positive effect on soil physical parameters than hairy vetch and pig manure. Therefore, different organic materials had differently active effect on physical parameters depending on types of soil and land use. Especially, it could be thought that well-decomposed organic materials have the advantage of an increase in organic matter content, while coarse organic materials of an increase in WSA.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.279-284
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• 1999

Fly ash is the fine ash particles that are flying out of chimney of the thermoelectric power plant where coals are used as fuel. There are two kinds of fly ashes from anthracite and bituminous coal. By scanning electron microscope(SEM) morphological feature of fly ash was confirmed to the exact spherical particles with the diameter variation from the fine to the largest about $50{\mu}m$(mainly silty particle). Surface of anthracite ash particle was very smooth but that of bituminous was somewhat coarse. To find the utilization of fly ash for improving soil permeability, soils of 4 kinds of different texture, clay, clay loam, sandy clay loam and sand mere applied with 7 levels of fly ash: 0, 10, 20, 40, 60, 80, 100%(w/w) and their saturated hydraulic conductivity(Ks) were determined at each application by constant head method. In clay soil with low water permeability, Ks value was increased about 10 times from $10^{-8}$ to $10^{-7}m\;s^{-1}$ level with application of 10% fly ash and it was slightly increased with increasing fly ash application from 40 to 80%. In clay loam Ks value was about $10^{-7}m\;s^{-1}$ level and its value was not influenced by the fly ash application. In sandy clay loam with relatively high permeability, Ks value was decreased about 10 times from $10^{-5}$ to $10^{-6}m\;s^{-1}$ level with application of 10% fly ash and also decreased about 50 times from $10^{-5}$ to $5.0{\times}10^{-7}m\;s^{-1}$ with application of more than 20% fly ash. In sand with very high permeability, Ks value was decreased about 10 times from $10^{-4}$ to $10^{-5}m\;s^{-1}$ level with application of 10% fly ash and also decreased about 100 times from $10^{-4}$ to $10^{-6}m\;s^{-1}$ level with application of 20% fly ash and continuously decreased about 500 times from $10^{-4}$ to $5.0{\times}10^{-7}m\;s^{-1}$ level with application of more than 40% fly ash. In conclusion by fly ash application saturated hydraulic conductivity was increased in clay soil, on the contrary it was decreased in sandy soils. Fly ash may be used as a material for amelioration of soil permeability.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.3
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• pp.145-160
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• 1979

The effects of organic material application on soil physical properties were reviewed in relation to soil productivity. The organic matter contents and soil physical properties of the cultivated land in Korea were summarized and the effects of organic matter were compared in terms of land uses and soil types. Soil physical properties related to crop yield potential, such as soil aggregation, permeability, water holding capacity, erodibility, and compactibility, were used in evaluating the effects of organic materials as a soil physical amendment. The benefical effects of organic matter addition on soil physical conditions include (1) better aeration and increased infiltration in silty and clayey soils, (2) increased water holding capacity and moisture availability in sandy soils, (3) decreased soil erodibility, and (4) increased resistance to compaction. It is, therefore, concluded that continuous application of organic materials could greatly improve the various soil physical properties and favor the growth and yield of crops. A high rate of organic matter addition could contribute to reducing not only the soil erosion on sloping land, but also the possible detrimental effect of farm mechanization. In general, the effects of organic matter on soil physical improvement were estimated to be much higher in upland than in paddy. Organic matter would have a more pronounced effect on low productive lands such as heavy clayey or sandy soils and newly reclaimed soil. The optimum level of soil organic matter content was estimated to be about 3.0 to 3.5% for the best soil physical condition. Since the organic matter contents of the cultivated lands in Korea are much lower than optimum level, it would be desiable to use more organic materials to soil for the increase of soil productivity, continuation of stabilized high productivity and soil erosion control.

• Korean Journal of Environmental Agriculture
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• v.14 no.1
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• pp.28-44
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• 1995

Residue level of myclobutanil[2-p-chlorophenyl-2-(1H-1,2,4-trizol-l-yl-methyl) hexane nitril] and number of soil microorganism were investigated at different environmental conditions such as the sterile and the non-sterile soils, moisture content, pH, temperature, application rate, and soil types under laboratory and field to study the effect of those factors on degradation characteristics of this fungicide and change of microflora in soil. Decomposition rate of myclobutanil was 3.9 times faster in the non-sterile soil than in the sterile soil, 1.6 times in the field than in the laboratory, 1.4 times in the concentration of 10ppm than in that of 20ppm, and 1.2 times in the clay loam soil than in the silty loam soil. Degradation rate of myclobutanil was the fastest at pH 9.0 among the tested pHs and the latest at pH 5.5. Degradation rate of myclobutanil was in order of $27^{\circ}C$ > $37^{\circ}C$ > $17^{\circ}C$. Otherwise, the effect of soil water content on myclobutanil degradation was found not clear. Number of microorganism in the non-sterile soil was remarkedly more than that in the sterile soil. Numbers of microbes were not significantly different between treatment plot and non-treatment plot of myclobutanil at the different conditions of soil moisture content, pH, temperature and soil type. Numbers of fungi and total microbes were more in the treatment than in the non-treatment of myclobutanil at field test but the same trends were not found at laboratory test. Within non-treatment of myclobutanil, numbers of microbes were not significantly different under the various condition of pH, application rate, and soil type in laboratory and upland field. The number of bacteria were more in 60% moisture content of water holding capacity than in 40% and the number of fungi were more in $17^{\circ}C$ of soil temperature than in $37^{\circ}C$. Within the application plot of myclobutanil, numbers of microbes were not significantly different at various pH in laboratory and upland field. The number of bacteria and total microbes were more in 80% moisture content of water holding capacity than in 40% and 60% and actinomycetes were more at $27^{\circ}C$ in the clay loam soil than at $17^{\circ}C$ in the silty loam soil.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.3
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• pp.224-231
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• 1984

Four kinds of soil conditioners, such as red earth, clayey tidal deposit, silty tidal deposit and tertiary deposit were evaluated for the rice growth and for the effectiveness of soil improvement in sandy paddy soil (Gangseo series) whose percolation and nutrient leaching are usually severe. Experiment was conducted at the farmer's field in Hackpo Ri, Bugog Myeon, Changyeong Gun, Gyeong Nam Province for two years (1980-1981) with using two rice varieties, Milyang 42 for 1980 and cheongcheongbyeo for 1981. For both experimental years, the grain yields were increased on the plots that were treated with soil conditioners compared with nontreated plot. The increase in grain yield was particularly high on the plots treated with clayey tidal deposit and teritary deposit. The dry weight of the plant and the uptake amount of inorganic ingredient tended to increase on the plots of clayey tidal deposit and tertiary deposit during whole rice growing season because of the residual effect of soil conditioners in the second experimental year. Cation exchange capacity, available silicate, exchangeable potassium and active iron was increased by the treatment with the soil conditoners. Especially cation exchange capacity was highest in the tertiary deposit treatment plot. Aggregation content and plastic index were increased for the all treatment plots with soil conditioner, however, hydraulic conductivity was conspicuously decreased by the tertiary deposit and clayey tidal deposit treatments.