• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.4
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• pp.373-378
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• 1999

This study was conducted to investigate the effects of application of the dolomite particles and the shell powder on soil characteristics, dry matter yield and nutritive value of forage in sandy loam soil at the Experimental Field of National Livestock Research Institute, Suweon, from 1994 to 1996. This was compared with control, lime, dolomite 0.5mm, 2.0mm, 4.0mm, and shell powder in mixed pasture. Although there was no significant difference, average dry matter yield for 3 years was increased with the application of lime, dolomite 2.0mm, 0.5mm, control, 4.0mm and shell powder in order. Average crude protein yield of forages was increased with the application of dolomite 2.0mm, 0.5mm, control, lime, shell powder and 4.0mm in order. Lime requirement was slightly increased from 2,410 to 4,853kg per ha with the lapse of time. Although soil hardness was optimum level by second year, it was apt to become hard little by little. Solid phase of soil was lowered with dolomite 0.5mm treatment. The results demonstrated that dolomite and shell powder could be settled a dust problem in farms and a coast pollution as lime substitutes for soil improvement. Therefore, it is desirable for dry matter yield and crude protein yield to applicate the dolomite 2.0mm every 3 years and the shell powder more frequently in sandy loam soil.

• Geomechanics and Engineering
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• v.12 no.5
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• pp.739-752
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• 2017

This study was intended to evaluate the improved strength of the ground by applying the bio grouting method to a loose sandy ground. The injection material was prepared in the form of cement-like powder, with the bio injection material produced by microbial reactions. The grouting test was conducted under the conditions similar to the field where the bio injection material can be applied. In addition, the injection materials (cement and sodium silicate No. 3) used for Labile Waterglass (LW) method and the conventional grouting methodwere prepared through a two-solution one-step process. The injection into the specimens was done at a pressure of 150 kPa and then, with a bender element, their moduliof elasticity were measured on the 7th, 14th, 21st and 28th curingdays to analyze their strengths according to the duration of curing. It was confirmed that in all injection materials the moduli of elasticity increased over time. In particular, when 30% of the bio injection material was added to 100% cement, the modulus of elasticity tended to increase by about 15%. This confirmed that the applicability became higher when the bio injection material was used in place of the conventional sodium silicate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.298-303
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• 2020

This study examined the washing conditions for high-quality solar salt. The salinity of the washing water was set to 5 % to prevent yield loss, and the temperatures of the washing water were 5, 10, 17.5, and 20 ℃. After washing the solar salt, the moisture content, salinity, insoluble matter, and sandy powder were measured from the solar salt. In addition, the color properties, L*[lightness], a*[redness], b*[yellowness], and yield were measured. The moisture content of the salt showed a tendency to increase when the temperature of the washing water was above 10 ℃, and the salinity and yield tended to decrease as the temperature of the washing water was high. The amount of insoluble matter decreased with decreasing temperature of the washing water. In the case of sandy powder, the highest value was 0.67 % at a washing water temperature of 5 ℃, and the value was 0.57 % under the other temperature conditions. Regarding the color properties, the b* [yellowness] of the color of the solar salt increased when the washing water temperature was high. This appeared to decrease the appearance quality. According to the above results, a washing water temperature above 10 ℃ was appropriate. The development of design factors of a high-quality solar salt production system is expected with experiments to define the drying conditions after the washing process.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.3
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• pp.47-53
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• 1999

This study was carried out to suggest the slope revegetation technology of biological engineering using the Ligustrum obtusifolium, which is one of the pioneer plant species. Ahead of the experimental construction, we evaluated the L. obtusifolium's value of biological engineering for the slope stabilization by testing the growth rate after the cuttings were buried for 8 weeks('98. 7. ~ '98. 9.). In this test, it was found that the L. obtusifolium, one of the species deep rooted with developed underground parts, is very effective for the slope stabilization and that the rooting powder(Hormex Powder) gave the better effects on root germination. In April of 1999, the experimental construction of biological engineering technology using recycled L. obtusifolium live cuttings(applied growth-stimulating compound) and green bags was conducted at sandy cut-slope in GLEN ROSS G.C.(Yongin). The slope was tolerant of soil erosion despite of heavy rainfall in the rainy season and many plant species invading for five months('99. 4. ~ '99. 9.). The vegetation research was performed through examining the frequency of each block using the transect method. 21 kinds of plant speices appeared in total area($25.5m^2$) and the dominant species are Digitaria sanguinalis, Setaria viridis, Cyperus amuricus, Persicaria blumei, Artemisia princeps var. orientalis. With regard to life forms, therophytes were shown with a dominant distribution of 66.7% of total species and neophytes relatively with a low distribution of 19.0%. Furthermore, it can be estimated that there is no ecological stabilization of this slope with the result of the ruderal species' occupation of 71.4%. It is too early to argue about ecological mechanical advantages and disadvantages of this technology, but, from the result of this study, it is expected that the slope revegetation technology of biological engineering using L. obtusifolium can be effectively applied to sandy slope(not rock or weathered rock slope) and that the early rapid stabilization and favorable succession could be done with the improvement of soil condition.

• Journal of Soil and Groundwater Environment
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• v.18 no.1
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• pp.67-77
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• 2013

To improve the energy efficiency of conventional thermal treatment, soil remediation with microwave has been studied. In this study, the remediation efficiency of contaminated soil with semi-volatile organic contaminants were evaluated with microwave oven and several additives such as water, formic acid, iron powder, sodium hydroxide (NaOH) solution, and activated carbon. For the experiment, loamy sand and sandy loam collected from Imjin river flood plain were intentionally contaminated with hexachlorobenzene and phenanthrene, respectively. The contaminated soils were treated with microwave facility and the mass removals of organic contaminants from soils were evaluated. Among additives that were added to increase the remediation efficiency, activated carbon and NaOH solution were more effective than water, iron powder, and formic acid. When 10 g of hexachlorobenzene (142.4 mg/kg-soil) or phenanthrene (2,138.8 mg/kg-soil) contaminated soil that mixed with 0.5 g iron powder, 0.5 g activated carbon and 1 ml 6.25 M NaOH solution were treated with microwave for 3 minutes, more than 95% of contaminants were removed. The degradation of hexachlorobenzene during microwave treatments with additives was confirmed by the detection of pentachlorobenzene and tetrachlorobenzene. Naphthalene and phenol were also detected as degradation products of phenanthrene during microwave treatment with additives. The results showed that adding a suitable amount of additives for microwave treatments fairly increased the efficiency of removing semi-volatile soil organic contaminants.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.2
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• pp.161-168
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• 1987

This study was conducted to evaluate the effects of potassium and sulfur power levels on the growth, nutrients' uptake at different growing stage and seed yield of peanut plant and changes of soil chamical properties in a sandy peanut cultivated soil of Nak-dong riverside in 1984. 1. The length of main stem, that of branch NO. and NO. of branches per plant were increased by the increased application of potassium and sulfur powdar. Especially sulfur powder treated plot were shown in positive effect with obtained in main root length, NO. of roots and Wt. of noudles formed per plant, roots' weight of peanut plant was much more than top's Wt. at harvesting stage, and so ratio of dry matter Wt. top/root was low. 2. The noudle's Wt. formed was positively significant recognized with dry matter Wt. of peanut plant at harvesting stage and the treatments of potassium were increased 7-20% compared with potassium non-treated plot and sulfur's treatments were increased 4-13% than that of potassium 15kg/10a treatment which was sulfur's non-treated plot in seed yield. 3. Relationship between all nutrients' uptake at flowering stage and seed yield were positively significant recognized, but $P_2O_5$ uptake and N/S ratio showed negative effect at harvesting stage of peanut plant. 4. By the increase of potassium and sulfur powder application, the soil pH at two different stages were almost not differential and the content of K, $P_2O$ and $SO_4$ in soil and $SO_4/P_2O_5$ ratio were increasing tendency.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.3
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• pp.262-270
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• 2012

This research was performed to find out the root characteristics of sweetpotato (Ipomoea batatas LAM.) cultivars according to the cultivation regions. Total 10 sweetpotato culivars, 6 yellow, 2 purple and 2 orange, were used for experiment. Samples were cultivated in Muan, Iksan, Nonsan, Boryeong and Hamyang. Precipitation and average temperature during the growth period of sweetpotato cultivation were 882~1,682 mm and 16.7~$28.2^{\circ}C$, respectively. Accumulated temperature was 3,122~$3,282^{\circ}C$. Soil texture was found of sandy loam in Muan, Iksan and Boryeong, sandy clay loam in Nonsan, and loam in Hamyang. The yield of root, dry matter content, starch value and soluble solids contents were high in Muan. The length/width ratio was high in Hamyang. The color values of sweetpotatoes were high in Nonsan. The protein content of sweetpotato powder was high in the Iksan, crude fat content and ash content were high in the Hamyang. The results of this study, we could see that root characteristics of sweetpotato in the same cultivars appeared differently depending on the cultivated regions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.147-157
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• 1973

I. The effect of excessive soil moisture(at the time of germination) on germination of barley and crop damage of herbicides was investigated. Machete(Butachlor) and TOK(Nitrofen) were treated, respectively, at the rate of 150g ai/10a on each pot whose different soil moisture content was controlled by suppling 30, 40, 50 and 60ml of water per 100gr of air-dried soil, respectively. The results are summarized as follows: 1. Excessive soil moisture beyond field moisture capacity caused great inhibition, from 20 to 100%, of the germination of barley even at untreated pots(check pots). Also, further development of root and growth of barley were greatly inhibited even though the seeds germinated. 2. The same tendency in inhibition of germination and growth as at untreated pots was observed at treated pots, too. As a whole, however, the damage were heavier at treated pots. II. Wanju naked spring barley was seeded on four different soils and covered with soil to a depth of 1 em, and then Machete, TOK, Saturn and HE-314 were treated at the rate of 180, 150 and 200, 150, and 250g ai/10a, respectively, and the effect of soil texture on crop damage of the herbicides was investigated. The results are summarized as follows: 1. Machete(emulsion and granule, at 180g ai/10a) The degree of crop damage was quite different from one soil texture to another: while almost no crop damage was observed on a clay loam soil regardless of the type of formulation, the damage became heavier as the soil texture became sandier as sandy clay loam, volcanic ash loam and sandy loam, and great inhibition of growth was observed on sandy loam soil. In general heavier damage was caused by the application of emulsion than by granular formulation. 2. TOK(Wettable powder, at 150, 250g ai/l0a) Almost the same tendency as in the application of Machete was observed, and the damage became heavier as the application rate increased. 3. Saturn(at l50g ai/l0a) No great difference in crop damage among soil textures was observed. 4. HE-3l4(at 250g ai/l0a) Almost no difference in crop damage among soil textures was observed at this rate of 250g ai/l0a. III. To study a difference of crop damage on soil covering depth(4 levels), 9 herbicides(TOK, MO, HE-3l4, Machete, Saturn, Simetryne, Simazine, Gesaran, Lorox) were treated on the pots with two different soils, and the effect of soil covering depth on crop damage of the herbicides was investigated. The results obtained in this experiment are summarized as follows: Light Clay Soil 1. The growth of barley in relation to depth of soil covering at check pots followed the order vigorous to weak; lcm>1.5cm>0.5cm>0cm. And in case of 0 and 0.5cm covering the growth of barley was very poor. 2. The damage at 0 and 0.5cm covering at treated pots was very severe, but Saturn, Machete, MO and TOK at 100 to l50g ai/l0a, respectively and He-3l4 at 250 to 375g ai/l0a were relatively safe to barley at the depths of lcm and above. 3. Simazine, Lorox and Simetryne caused slight damage even at 1.5cm covering. Sandy Loam Soil The growth of barley in relation to depth of soil covering at untreated pots followed the order, from vigorous to weak; 1.5cm 0.5cm 3cm 5cm. While MO was safe to barley at 1.5cm covering, for other chemicals more than 3cm covering was require for safe use. Machete and Saturn at 100g ai/l0a, and HE-3l4 at 250g ai/l0a was relatively safe at more than 3cm covering. Simazine, Lorox, Simetryne and Gesaran were unsafe on sandy soil regardless of covering depth.

• The Journal of Engineering Geology
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• v.31 no.4
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• pp.493-506
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• 2021

Liquefaction refers to a phenomenon in which excessive pore water pressure occurs when a dynamic load such as an earthquake rapidly acts on a loose sandy soil saturated with soil, and the ground loses effective stress and becomes liquefied. The indoor repeated test for liquefaction evaluation can be confirmed through the repeated triaxial compression test and the repeated shear test. In this regard, this study tried to confirm the liquefaction resistance strength according to the relative density and particle size distribution of sand using the repeated triaxial compression test. As a result of the experiment, it was confirmed that the liquefaction resistance strength increased as the relative density increased regardless of the soil classification, and the liquefaction resistance strength according to the particle size distribution of the sand was confirmed that the liquefaction resistance strength of the SP sample close to SW was significantly higher. In addition, as a result of analyzing 30% of fine powder compared to 0% of fine powder, as the relative density increased to 40~70%, the liquefaction resistance strength decreased by 5~20%, and the domestic weathered soil ground had a fine liquefaction resistance strength compared to Jumunjin standard sand. When the minute was 10%, it was measured to be 30% or more, and when the fine particle was 30%, it was measured to be less than 50%.

• Korean Journal of Pharmacognosy
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• v.9 no.3
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• pp.149-156
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• 1978

The result of the study about the cultivation, the constituents, the sweetenity, and the development of preparations of Stevia and Hydrangea are as follows: 1. Hydrangea thrived at $200{\sim}1,400m$ above the sea-level, and the good ones were brought up at $600{\sim}1,200m$. 2. The good ones which belonged to the genera of Hydrangea were produced in the damp, dark and cold place. 3. The growth and cultivated yield of Stevia was not significantly influenced by the acidity of the soil. 4. The best season was May and June for propagation of Stevia by cutting method. 5. The growth rate of Stevia and Hydrangea was really good in the sandy fertile soil, but in the mucotic soil it was not suitable. 6. The extraction and separation of phyllodulcin by solvent had many difficulties, because it was very soluble in water, ethanol, ether, petroleum ether, acetone and benzene, etc. 7. The solubility of stevioside on the solvent was as follows: It was very soluble in water and methanol, slightly soluble in ethanol and acetone, and insoluble in ether, petroleum ether and chloroform. 8. The alkaloid reaction by Mayer reagent in Hydrangea extract was positive. 9. The ashification rate of Stevia was 8.66% to 8.72% and that of Hydrangea 17.02% to 17.04%. 10. The tannin of Stevia leaf was 7.80% to 7.88% and its of Hydrangea decreased 9.46% to 6.08% by fermentation. 11. The percent rates in minimum concentration-occurring sweetness in sugar, glycyrrhiza methanol extract, Hydrangea water extract, Stevia leaf water extract, decoction of Stevia's leaf, decoction of Stevia's stem were as follows: 1.2, 0.1, 0.1, 0.2, 0.4, 0.01, 0.1, 0.6. and sweetenity ratios of those were 1, 12, 12, 6, 3, 64, 12, 2, 12. It was very meaningful to develop preparations of stevia as stevioside, micronized powder, water extract, methanol extract and compound teas and in Hydrangea, water extract, methanol extract, single tea, and compound teas were less meaningful. 13. The genera of Hydrangea which is natural species in Korea was positive in phyllodulcin-identification test, but it was not available to make the sweet tea because of having a little content.