• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.482-487
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• 2007

This study was conducted to investigate the effect of long-term continuous application of fertilizers for rice cultivation. Changes of physical and chemical properties of paddy soil and the rice yield by continuous application of NPK fertilizers, ammonium sulphate, and urea over fifty years, from 1954 to 2003, were investigated. The rice yield index of each treatment were 100 of NPK plots, 84 of ammonium sulphate plots, 81 of urea plots, and 62 of no fertilizer plots. The variance of yield was large according to the quality of irrigation water. Nutrient uptakes by rice plants in ammonium sulphate and urea plots were significantly smaller than those in NPK plots; 86 and 75% in T-N, 79 and 82% in $P_2O_5$, 64 and 58% in $K_2O$, and 94 and 90% in $SiO_2$, respectively. Bulk density of soil in NPK plots significantly decreased compared to those in no fertilizer, ammonium sulphate, and urea plots, whereas CEC in NPK plots increased compared to other plots. Soil pHs of all plots were higher than that before experiment which was 5.2; 6.0 in no fertilizer, 5.9 in urea and NPK, and 5.4 in ammonium sulphate plots. The available phosphate in soil increased by $2.5mg\;kg^{-1}\;yr^{-1}$ when $70kg\;ha^{-1}$ of P fertilizer applied for rice cultivation, and decreased by $1.8mg\;kg^{-1}\;yr^{-1}$ when no P fertilizer applied.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.1
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• pp.36-42
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• 2013

In an experiment of organic manure to substitute for chemical fertilizers in rice-cropping, the amount of applied fertilizer tended to increase pH and organic matters, depending on chemical characteristics of soil with organic fertilizers. At first, that tendency about growth characteristics was shown in treatment group, which was applied organic manure and chemical fertilizers, comparing with control group. However, after growing period, leaf area, fresh weight, and dry weight in seventh treatment group applied 12 kg / 10 a of organic manure was higher than in other groups. There was no significant difference of the number of glumous flowers or percent ripened grain in terms of yield component, and control group and treatment group yielded above 500 kg per 10a. Especially, the highest figure was from seventh treatment group, 538 kg / 10 a. Furthermore, quality of rice grain showed not much difference, depending on whether or not applying organic fertilizers. As a result of the experiment, applying organic manure improves the physical property of soil. It is clear that organic fertilizers can be substituted for chemical ones since there is no difference from yield component and quality of brown rice, comparing with chemical fertilizers which have been used conventionally. The proper amount of organic manure is 267 kg per 10a; it makes good quality of yield.

• Journal of the Korean Geotechnical Society
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• v.28 no.4
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• pp.91-100
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• 2012

Soil-water characteristic curves (SWCCs), which represent a physical property in partially saturated soils, show the relation between volumetric water content and matric suction. The SWCCs exhibit hysteresis during wetting and drying, however experimental expressions used to describe SWCCs have generally ignored the hysteresis. In addition, the shape of SWCC may depend on the void ratio which is changed by soil skeleton deformations or hysteretic behavior under various loading conditions. Hence, it is necessary to understand, both empirically and analytically, the relationship between soil skeleton deformations and the SWCCs of various soils. The typical SWCCs experimentally have drying, wetting, and the second drying curve. The measurement of a complete set of hysteretic curves is severely time-consuming and difficult works, then the first drying curve of SWCC is generally determined to estimate the hydraulic conductivity and shear strength function of partially saturated soils. This paper presents the hydraulic-mechanical behavior of partially saturated soils (weathered soil and silty soil) for volume changes and hysteresis in SWCCs regarding the difference between the first drying and wetting curve.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.252-258
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• 2018

A larger energy consumption and concentration of population induced green house gas glowing and heat island effect in the urban space. Roof green system was a effect method to reduce green house gas and heat concentration in the city. Therefore, construction of this system was increasing. Most of lightweight soil used in roof green system was perlite, but this caused dust and skin disease. So it needed to develop another new lightweight soli for roof green system. Meanwhile, a thermoelectric power plant generated bottom ash as a by-product. According to previous research, bottom ash could be used for artificial lightweight soil with 60 wt% of mixing rate. But this study was proceed to develop a artificial lightweight soil using bottom ash with higher mixing rate by 65 wt% and different organic ingredients. First, physical and chemical properties of bottom ash was investigated. Then test according to landscaping design standard was proceeded for various artificial lightweight soil mix types using bottom ash, bark, compost and coco peat. As a result, the artificial lightweight soil with 65% of bottom ash, 30% of bark and 5% of compost was suitable for low and middle range of soil standard.

• Geophysics and Geophysical Exploration
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• v.7 no.2
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• pp.130-135
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• 2004

This paper describes the physical properties of the factors controlling the electrical resistivity of the subsurface. Resistivities of various types of soil and rock samples saturated with sodium chloride solutions having nine different concentrations were measured, and the measured resistivities of these samples were compared with calculated resistivities obtained using the conventional empirical formulas. From the results obtained, we observed that the resistivity of the soil and rock samples increases with increasing in pore-fluids resistivity regardless of the media type. However, between 20 and 200 ohm-m, which is the normal range of resistivity of groundwater, the resistivity of the pore-fluids have little or no effect on the resistivities of the samples used. Below 10 ohm-m, the resistivities of the samples are mainly controlled by the pore-fluids, whereas, in the normal range of resistivity of groundwater, the sample resistivities are controlled by their intrinsic matrix resistivity more than by the pore-fluids resistivity. Also, the measured resistivity of rock and soil samples having more than $20\%$ clay contents showed a good agreement with the calculated resistivity using the parallel resistance model whereas, the calculated resistivities of glass beads correlate with that obtained using Archie's formula. When the pore-fluid resistivity is high, the computation of the resistivity values of the samples using the Archie's formula could not be carried out. Through this study, we were able to confirm that the tests are only applicable to the parallel resistance model considering the intrinsic matrix resistivity within the normal resistivity range of groundwater in the subsurface.

• Journal of the Korean Geosynthetics Society
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• v.22 no.2
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• pp.63-70
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• 2023

Most of the industrial complexes and housing complexes in Busan and Gyeongnam were constructed by developing mountainous areas, except for some landfill areas. During the development process, the surplus soil for site development was mainly used as the embankment material. In the field, however, even if the material of the material changes during the embankment work for site development, for convenience reasons such as construction period and site conditions, the material property test and compaction test are not additionally conducted for the embankment material, and quality control is conducted. In this study, physical property tests and compaction tests were conducted on surplus soils in mountainous areas in Busan, GyungNam Province and then regression analysis was performed on the data. In addition, a comparative analysis was conducted along with existing studies in Korea. The surplus soils at the sites in Busan and Gyeongnam were mainly weathered soils of granites, and were classified into clayey sand (SC) and silty sand (SM). As a result of regression analysis of the compaction characteristics according to the content of coarse and fine soils, the correlation between them was very high. Using the relational formula as a result of this study, it will be very useful for compaction management of the surplus soils in the field.

• Journal of the Korea Fashion and Costume Design Association
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• v.9 no.2
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• pp.85-92
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• 2007

This study focused on bean-juice treatment method which have dyeing property to indigo, yellow soil, sappan wood, cochineal and also on the possibility of applying to mordanting. This is different from the active mordanting using chemicals. Natural mordants with development of dyeing are not harmful, also are the medicines for disease. Limestone and ash neutralize the acidic soil. bean-juice protein adhere to cellulose surface and change the physical properties of protein so that coloring of dye is better than before and film non-soluble in water is made. Therefore the color made from bean-juice process lasts after washing. This study try to show one of the ways to improve the current method using the heavy metal which can have bad effects for environment and human being. Bean-juice(raw bean, heated bean) treatment method can be the way to fix the natural dyeing problem of bad dyeing. Bean-juice had been treated under various condition with pre-treatment, post-treatment and raw bean, heated bean. Following results are obtained in this study. In the case of Indigo dyeing, pre-treatment of heated bean shows the biggest difference of color. In the case of yellow soil dyeing, pre-treatment of raw bean-juice shows the biggest gap of color. Pre-treatment of heated bean in sappan wood dyeing case and post-treatment of raw bean show bigger color difference than pre-treatment of raw bean. In cochineal dyeing, raw bean pre-treatment shows the biggest color difference.

• Korean Journal of Medicinal Crop Science
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• v.18 no.2
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• pp.74-78
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• 2010

This experiment was carried out to select suitable organic matter in To-jik nursery (self soil nursery) for complement To-jik nursery's defects that are deterioration of raw material by poor quality of seed ginseng and reduction of the quantity in seed ginseng production. Organic matter used were Yacto, rice bean, defatted rice bran, soybean cake and their mixture. As follows, bulk density in soil physical property by treating organic composts was the greatest in soybean cake and the next was followed by mix, Yacto, defatted rice bran, and rice bran treatment in order. Soil pore space ratio was totally the opposite; that was rice bran the first and followed by defatted rice bran, Yacto, mix and soybean cake treatment. The incidence rate of damping off by treating organic composts was 1.5% in both soybean cake and mix while the others was 1.0%. Emergence time was the same among treatment on April 16 and Emergence rate was the highest at 73% in Yacto. There was no significant differences among treatment in the growth of aboveground part but it was a little better in defatted rice bran treatment. In Yacto treatment, the growth of underground part, total root number per kan, rate of first grade ginseng seedling, and rate of usable ginseng seedling etc. were entirely higher but there was little differences. Using defatted rice bran was slightly lower in productivity compared to Yacto, but the possibility was high as a alternative for Yacto in a view of managing cost down.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.129-134
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• 2010

This paper investigates effects of rubber inclusion on the strength and physical characteristics of rubber.added composite geomaterial (CGM) in which dredged soils, crumb rubber, and bottom ash are reused for recycling. Several series of test specimens were prepared at 5 different percentages of rubber content (i.e. 0%, 25%, 50%, 75%, and 100% by weight of the dry dredged soil) and three different percentages of bottom ash content (i.e. 0%, 50% and 100% by weight of the dry dredged soil). The mixed soil specimens were subjected to unconfined compression test and elastic wave test to investigate their unconfined compressive strengths and small strain properties. The values of bulk unit weight of the CGM with bottom ash content of 0% and 100% decrease from 14kN/$m^3$ to 11kN/$m^3$ and 15kN/$m^3$ to 12kN/$m^3$, respectively, as rubber content increases, because the rubber had a specific gravity of 1.13. The test results indicated that the rubber content and bottom ash content were found to influence the strength and stress-strain behavior of CGM. Overall, the unconfined compressive strength, and shear modulus were found to decrease with increasing rubber content. Among the samples tested in this study, those with a lower rubber content exhibited sand-like behavior and a higher shear modulus. Samples with a higher rubber content exhibited rubber-like behavior and a lower shear modulus. The CGM with 100% bottom ash could be used as alternative backfill material better than CGM with 0% bottom ash. The results of elastic wave tests indicate that the higher rubber content, the lower shear modulus (G).

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1230-1236
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• 2012

To verify that the electrokinetic remediation is effective for decreasing salinity of fields of the plastic-film house, field tests for physical property, chemical property, and crop productivity of soils have been conducted. The abridged result of those tests is as follows. In the EK treatment, the electrokinetic remediation has been treated at the constant voltage (about 0.8 V $cm^{-1}$) for fields of the farm household. At this time, an alternating current (AC) 220 V of the farm household was transformed a direct current. The HSCI (High Silicon Cast Iron) that the length of the stick for a cation is 20cm, and the Fe Plate for an anion have been spread out on the ground. As the PVC pipe that is 10 cm in diameter was laid in the bottom of soils, cations descend on the cathode were discharged together. For soil physical properties according to the EK treatment, the destruction effect of soil aggregate was large, and the infiltration rate of water was increased. However, variations of bulk density and porosity were not considerable. Meanwhile, in chemical properties of soils, principal ions of such as EC, $NO_3{^-}$-N, $K^+$, and $Na^+$ were better rapidly reduced in the EK treated control plot than in the untreated control plot. And properties such as pH, $P_2O_5$ and $Ca^{2+}$ had a small impact on the EK. For cropping season of crop cultivation according to the EK treatment, decreasing rates of chemical properties of soils were as follows; $NO_3{^-}$-N 78.3% > $K^+$ 72.3% > EC 71.6% $$\geq_-$$ $Na^+$ 71.5% > $Mg^{2+}$ 36.8%. As results of comparing the experimental plot that EK was treated before crop cultivation with it that EK was treated during crop cultivation, the decreasing effect of chemical properties was higher in the case that EK was treated during crop cultivation. After the EK treatment, treatment effects were distinct for $NO_3{^-}$-N and EC that a decrease of nutrients is clear. However, because the lasting effect of decreasing salinity were not distinct for the single EK treatment, fertilization for soil testing was desirable carrying on testing for chemical properties of soils after EK treatments more than two times. In the growth of cabbages according to the EK treatment, the rate of yield increase was 225.5% for the primary treatment, 181.0% for the secondary treatment, and 124.2% for third treatment compared with the untreated control plot. The yield was increased by a factor of 130.0% for the hot pepper at the primary treatment (Apr. 2011), 248.1% for the lettuce at the secondary treatment (Nov.2011), and 125.4% for the young radish at the third treatment (Jul. 2012). In conclusion, the effect of yield increase was accepted officially for all announced crops.