• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.539-542
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• 1999

In this study, acrylate salt material of new chemical composition for injection grouting was prepared in the state of aqueous solution, and the chemical and physical properties of the material were investigated. The gelation time of the material was freely controllable through the control of added catalysts amount. As the viscosity of the material was very low (2∼3cps), its injection efficiency was expected to be very excellent. The variation of its viscosity plotted with the process of gelation revealed that the efficiency of its penetration into the ground soil was very excellent. The LD$\sub$50/ test on white mouse verified the toxicity of the material was very slight and substantially negligible. The grouting effect using the material was examined through field case histories.

• Journal of the Korean Geotechnical Society
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• v.38 no.5
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• pp.61-71
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• 2022

Soil color is used to determine soil classification and its physical, chemical, and biological properties. Visual determination is the most commonly used method for identifying soil color. However, it is subjective and, in many cases, non-repeatable. Digital image processing obtains useful information from digital images, accelerates soil classification, and enables the rapid identification of soil types in a field. This study develops a digital image processing-based soil color analysis technology that can consider irregular light conditions in the field. The digital image studio was designed to simulate the characteristics of natural light (illuminance and color temperature). Also, digital images of two soil samples (Jumoonjin sand and Anseong weathered soil) were captured under 12 different light conditions. For the RGB and CIELAB color systems, soil color intensities of 24 images were obtained using digital image processing. CIELAB was suitable for dealing with irregular light conditions in the field.

• Korean Journal of Organic Agriculture
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• v.22 no.3
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• pp.413-421
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• 2014

This study was conducted into the effects of cover crops among the hairy vetch, red clover, rye, and hairy vetch+rye on the soil chemical and physical properties, and fruit yield in mature 'Fuyu' persimmon (Diospyros${\times}$kaki Thunb.) trees. The shallow-rooted red clover had poor dry matter production, resulting in the lowest coverage (66%) on the orchard floor. In contrast, the highest dry matter production observed in rye and hairy vetch+rye. Estimated N, P and K production from the cover crops were the highest on the hairy vetch+rye plots, increasing soil chemicals at a depth of 0-30 cm soil. Rye or hairy vetch+rye treatments decreased the soil bulk density and solid phase. As the hairy vetch+rye treatment increased fruit yield and sugar contents, it could be proposed as an suitable cover crop for improving productivity of persimmon trees.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.622-627
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• 2012

The processes to determine the composition, dynamics, and activity of infection mechanisms by the rhizosphere microflora have attracted the interest of scientists from multiple disciplines although considerable progress of the infection pathways and plant-pathogen interactions by soil borne fungal pathogens have been made. Soilborne pathogens are confined within a three-dimensional matrix of mineral soil particles, pores, organic matter in various stages of decomposition and a biological component. Among the physical and chemical properties of soils soil texture and matric water potential may be the two most important factors that determine spread exudates by soil borne fungal pathogens, based on the size of the soil pores. Pathogenic invasion of plant roots involves complex molecular mechanisms which occur in the diffuse interface between the root and the soil created by root exudates. The initial infection by soilborne pathogens can be caused by enzymes which breakdown cell wall layers to penetrate the plant cell wall for the fungus. However, the fate and mobility of the exudates are less well understood. Therefore, it needs to develop methods to control disease caused by enzymes produced by the soilborne pathogens by verifying many other possible pathways and mechanisms of infection processes occurring in soils.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.749-758
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• 2019

The aim of this study is to provide a scientific basis for decision making regarding environmental damage in case of future chemical accidents by evaluating the ecotoxicity of 4 substances requiring preparation for accidents. For this purpose, acute and chronic toxicities of nitric acid, sulfuric acid, hydrogen peroxide, and ammonia solution, which can change the physical and chemical properties of soil to Paronychiurus kimi(Collembola) were investigated. The pH of artificial soil spiked with a series of test chemical concentrations was also measured. The pH of soil spiked with 10,000 mg kg^-1 of soil nitric acid, sulfuric acid, hydrogen peroxide, and ammonia solution were 2.86, 2.72, 7.18 and 9.69, respectively. The 28-d LC₅₀ of nitric acid, sulfuric acid, hydrogen peroxide and ammonia solution were 2,703, 5,414, 3,158 and 859 mg kg^-1 soil dry wt., respectively and 28-d EC₅₀ were 587, 2,148, 1,300 and 216 mg kg^-1 soil dry wt., respectively. These results indicated that the mortality and juvenile production of P. kimi were influenced by not only the soil pH but also by the reduced organic content and products produced by the reaction of soil with the tested chemicals. Given the fact that most substances requiring preparation for accidents can change soil characteristics, assessment and restoration methods that take into account changes in soil properties are needed for accurate decision making after chemical accidents.

• Journal of Korea Soil Environment Society
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• v.1 no.1
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• pp.81-88
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• 1996

To study the Cd adsorption in the presence of competing ions in soil-solution interphase, three soil samples from the Bt horizon were taken and analyzed for their physical and chemical properties. Adsorption of ethylene glycol monoethyl ether(EGME) and N, were determined to establish the specific surface area of the soils. We attempted to establish a qeneralizing competitive sorption isotherms for soils of entirely different composition of the solid phase, resulting in the routine use as a guidelines for the fate of reactive solute in soil profiles. Many physicochemical factors including competitive adsorption bettween solutes will affect the general adsorption phenomena as shown in a single not only on the soil:solution ratio used, but also on the surface areas of its respective soil samples. This phenomenon was attributed to competition Cd for sorption sites with Mg by different soil constituents. These adsorption isotherms are able to use as examples to demonstrate that this phenomenon can complicate the development of a standardized batch adsorption procedure as well as interpreting fate and adsorption of toxic inorganic compounds.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.641-649
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• 2011

This study was to analyze the soil environmental characteristics and vegetation status of green roof in Daejeon Metropolitan City. The investigated floras of vascular plants are 17 families, 26 genera, 28 species in Seo-Gu Daejeon District Office Building (SG), 25 families, 49 genera, 56 species in Galma Public Library (GP), and 34 families, 57 genera, 60 species in Daejeon City Hall (DC) respectively. Although the larger area shows the more numbers of species in introduced plants and naturalized plant, the naturalized plant ratios were similar with each other. They were 10.71%, 10.71%, and 11.67% at SG, GP, and DC respectively. As a result of analysis on soil physical property, soil depths including vegetation soil and drainage soil of 3 green roofs were 30cm. The depths of vegetation soil at SG, GP, and DC were 0~8cm, 0~10cm, 0~10cm respectively. As a results of soil chemical properties of our study, soil pH of vegetation soil and drainage soil were a range of 6.42 and 7.43, and a range of 6.55 and 7.43 on the average respectively. Available-P contents of vegetation soil and drainage soil were a range of 153.33 and 366.33mg/kg, and a range of 136.67 and 242.67 mg/kg which is very high, respectively. Carbon contents in soil at vegetation soil and drainage soil were a range of 3.16 and 6.38%, and a range of 1.63 and 2.47% respectively. Carbon storage per square meter within 30 cm were 2.76 kg, 2.99 kg, and 3.66 kg at SG, GP, and DC respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.1
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• pp.34-48
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• 2024

The objective of this study was to evaluate the safety of biodegradable mulching films in soybean (Glycine max) cultivation by measuring their effects on crop growth and yield, film decomposition and soil chemical and physical properties. In 2022 and 2023, plant height, branch number, chlorophyll contents, yield components, and yield of soybean did not vary significantly in areas using PE films and biodegradable mulching films. The light transmission rate of the biodegradable mulching films ranged from 6.4 to 15.8% when measured 112 days after soybean transplanting, and was higher, on average, in 2023 than in 2022. In both years, degradation of the biodegradable mulching films began 20 days after soybean transplantation and increased over time. In addition, remains of biodegradable mulching films were present in fields at soybean harvest and remained until 50 days after harvest. Decomposition rates of the biodegradable mulching films at 112 days after soybean transplanting ranged from 9.8 to 26.7% in 2022 and 13 to 36% in 2023. Although soil pH and EC varied based on the year and timing of measurements, there was no significant difference between areas that used biodegradable mulching films and PE films. Soil organic matter, nitrate and exchangeable cation contents such as Ca, Mg, and K were not significantly different in areas that used both PE films and biodegradable films. However, significantly higher levels of available phosphoric acid content were measured in areas that used biodegradable mulch films E, S, and T. Regardless of which films were used, there were no significant differences in the soil's physical properties. In 2022 and 2023, there was no difference between areas that used biodegradable mulch films and PE films. However, soil temperature in mulched areas was 2℃ higher and soil moisture was 5-15% higher than in non-mulched areas. Barley growth was not affected by being planted in soil that had been used for soybean cultivation with biodegradable films. Therefore, the biodegradable mulch films used in this study can be used without negatively affecting the growth, yield, and soil environment of soybeans.

• Journal of Soil and Groundwater Environment
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• v.18 no.3
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• pp.58-64
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• 2013

This study proposed a low temperature hydrothermal carbonization to treat and recycle sewage sludge and determined the optimal conditions for the biochar production. The physical and chemical properties of biochar were analyzed and its sorption capacity for heavy metals was evaluated. To produce biochar, 50 g of sewage sludge was heated at 220, 230, and $240^{\circ}C$ for 1, 2, 3, 5, 8, and 10 hours in a reactor. The optimal conditions to produce biochar was $230^{\circ}C$ and 8 hours. Sorption capacity tests were conducted for arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn) and nickel (Ni). Among them, lead was shown the highest heavy metal adsorption efficiency of biochar, followed by copper, cadmium, zinc, and nickel, but arsenic was hardly adsorbed overall.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.2
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• pp.55-62
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• 2000

In order to make the reasonable irrigation plan in the unripended tidal reclaimed paddy fields, the estimation of irrigation water requirements by soil textures and water management methods for the normal growth of crops is very important . This study was carried out to determine leaching requirements before cultivating crops. For the purpose of this study, the physical and chemical properties of soil samples used in the desalinization experiments were analyzed, and change of salinity by supplying water and leaching water were investigated in the experimental field with lysimeters. As a result considering the soil textures, desalinization effects of good drainage soils(S1) were better than those of poor drainage soils (S2). In the changes of salinity of the soils with supplying water by water management methods, among the good grainage soils with culvert treatment(S1CW), salinity of S1CW3 with 1, 120mm and S1W4 with 1, 440mm supplying water were 2.6dS/m and 1.1dS/m respectively, and salinity of S1NW4 with 1.680mm among those non-culvert treatment (S1NW) was 3.0dS/m, less than critical salanity value 3.0dS/m. On the other hand, of the poor drainage soils with cultvert treatment , salinity of S2CW3 was ranged 9.4-6.0dS/m with supplied water, and that of non-culverted treatment S2NW as 12.3-8.4dS/m.