• Journal of Korean Society for Atmospheric Environment
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• v.17 no.2
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• pp.203-212
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• 2001

During the growing season from June to August, 2000, the soil NO and $N_2$O fluxes were measured to elucidate characteristics of soil nitrogen emissions from different types of intensively managed agricultural soils at outskirts of Kunsan City, located in the western inland of Korea, Flux measurements were made using a closed chamber technique at two different agricultural fields; one was made from upland field, and the other from rice paddy field. The flux data from upland field were collected for both the green onion and soybean field. Concentrations of NO and $N_2$O inside a flux chamber ar 15 minute sampling interval were measured to determine their soil emissions. Either polyethylene syringes of teflon air bags were used for gas samples of $N_2$O and NO. The analysis of NO and $N_2$O was made using a chemiluminesence NO analyzer and GC-ECD, respectively no later than few hours after sample collection at laboratory. The gas fluxes were varied more than one standard deviation around their means. Relatively high soil gas emissions occurred in the aftermoon for both NO and $N_2$O. A sub-peak for $N_2$O emission was observed in the morning period, but not in the case of NO. NO emissions from rice paddy field were much less than those from upland site. It seems that water layer over the rice paddy field prevents gases from escaping from the soil surface covered with were during the irrigation and acts as a sink of these gases. The NO fluxes resulted from these field experiments were compared to those from grass soil and they were found to be much higher. Diurnal and daily variations of NO and $N_2$O emission were discussed and correlated with the effects of nitrogen fertilizer application on the increase of the level of soil nitrogen availability.

• Analytical Science and Technology
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• v.30 no.6
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• pp.338-347
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• 2017

The purpose of this study is to investigation of the decomposition characteristics in a pilot-scale burial site of livestock in three kinds of typical soils in Korea: sandy loam soil, clay loam soil, and sandy soil. In this study, we confirmed that most of the animals in the condition were decomposed within three years as mentioned in the "Livestock burial regional environmental research guidelines." We also determined that the decomposition rate of dead cows was higher than that of dead pigs, and that the biodegradation rate depends on the soil types in the following order: sandy soil > clay loam soil > sandy loam soil. The various external environment factors, such as temperature, moisture, pH, earthiness, nutrient, and the burial depth, should be managed properly for appropriate decomposition of dead animals.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.97-104
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• 2015

When carrying out design for soft ground improvement before reclamation of dredged soil, it is very important to appropriately evaluate design parameters such as compression index and undrained strength in order to estimate optimum construction cost. In this study, consolidation and strength parameters were estimated by the samples obtained from the similar reclaimed land. Water content and compression index of dredged soil reclaimed by hydraulic fill method were quite decreased in comparison with those of in-situ conditions at Incheon site. Relationships between compression index(Cc) and water content (wn), and between undrained strength (su) and water content (wn) for dredged soil were obtained by field vane test and oedometer test, respectively. Applicability of Schmertmann correction method (compression index) for low plasticity silty soil was discussed according to comparison with designed and measured settlements.

• Journal of Ecology and Environment
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• v.36 no.2
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• pp.131-140
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• 2013

In Korea, many paddy fields in mountainous area have been abandoned because of their low accessibility and rice price and the abandoned paddy terraces have changed into natural lentic wetlands. To understand the relationship between characteristics of environmental conditions and early development of plant community in abandoned paddy terraces, we investigated at four well-maintained abandoned paddy terraces in 3 different climatic zones in Korea. Soil texture of abandoned paddy terraces was mostly kinds of loam and electric conductivity of soil was also similar among abandoned paddy terraces. On the other hand, contents of nitrogen, phosphorus, potassium, sodium, magnesium, and calcium in soil were relatively low and significantly different among abandoned paddy terraces. Water depth was different within sites and inter-sites. Although environmental conditions including climate, soil condition and water depth were different among abandoned paddy terraces, the compositions of plant communities were relatively similar in all abandoned paddy terraces. 55 dominant taxa out of 141 recorded species were commonly recorded over sites and they were mostly perennial obligate wetland plants and facultative wetland plants. 8 taxa out of 55 dominant taxa occurred at all abandoned paddy terraces with over 10% coverage. Several site-specific species occurred at site, which have some area with deep water level. This result indicates that early development of plant community in abandoned paddy terraces of similar water regime is similar in the entire area of Korea even though environmental conditions such as climate, biogeographic history and soil are different.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.623-634
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• 2007

The aim of this research is development and verification of resistivity seismic dilatometer (RSDMT) system. The resistivity module for obtaining resistivity-depth plot and seismic module for obtaining wave velocity-depth plot are attached to the conventional flat dilatometer testing equipment. To enhance reliability and repeatability of seismic part in RSDMT, automatic testing system including automatic surface source, PC based data acquisition system and operating program were developed. To obtain real resistivity value of soil, geometric factor for the array of electrodes in RSDMT was derived empirically. The verification studies for the developed RSDMT system were performed at the southeast side of Korea where soil improvement work is planned. SPT, CPT, geophysical subsurface imaging techniques and some laboratory tests were performed for the comparisons. As one penetration of RSDMT, various soil parameters could be obtained. The results of field test showed good repeatability and reliability in every part. From these studies, developed RSDMT system was checked and the effectiveness of this system was verified in light of proper evaluation of geotechnical characteristics of soft soil.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.101-115
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• 2005

For the site characterization at two inland areas, Gyeongju and Hongsung, which represent geomorphic and geologic characteristics of inland region in Korea, in-situ seismic tests containing borehole drilling investigations and resonant column tests were peformed and site-specific seismic response analyses were conducted using equivalent linear as well as nonlinear scheme. The soil deposits in Korea were shallower and stiffer than those in western US, from which the site coefficients and site classification system in Korea were derived. Most sites were categorized as site classes C and D based on the mean shear wave velocity $(V_s)$ of the upper 30 m $(V_s30)$, ranging between 250 and 650 m/s. According to the acceleration response spectra determined from the site response analyses, the site coefficients specified in the current Korean seismic design guide underestimate the ground motion in the short-period band and overestimate the ground motion in mid-period band. These differences can be explained by the differences in the bedrock depth and the soil stiffness profile between Korea and western US. The site coefficients, $F_a$ for short-period and $F_v$ for mid-period, were re-evaluated and the site classification system, in which sites C and D were subdivided according to $V_s20,\;V_s15,\;and\;V_s10$ together with the existing $V_s30$ was introduced accounting for the local geologic conditions at inland region of the Korean peninsula. The proposed site classification system in this paper is still rudimentary and requires modification.

• Membrane and Water Treatment
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• v.14 no.4
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• pp.147-153
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• 2023

Urbanization has been causing such new pollutants as micro-plastic, thus the environmental impact of new pollutants on ecosystem is rapidly increasing. When it comes to micro-plastic, a representative artificial trace pollutant, its risk has been increased at a much faster rate, however the depth study associated with stormwater sediment and wetland was relatively rare. In this research, soil samples from storm water sediment were analyzed for distribution characteristics of micro-plastics in the J wetland (registered as Ramsar wetland, May 2021 and a representative environmental site in South Korea). Analyzed soil samples found approximately 201 ± 93 particle/kg (based on unit weight, Total micro plastic particles / Total Sample weight) micro-plastics in the samples. When considering the total quantitative numbers in stormwater sediment in the entire area of the J wetland, over 15,000 micro-plastics were estimated to be contaminating such area. In addition, in terms of qualitative numbers, micro-plastics were contaminating the J wetland with 94.7 % ratio of styrofoam type (43.9%) and polyethylene type (50.8%). These research results can be used as base data sets for controlling micro-plastics in the J wetland.

• Ecology and Resilient Infrastructure
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• v.7 no.2
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• pp.97-113
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• 2020

Soil is the foundation of human life and the basis for food security. Considering this it is prioritized in the UN's Sustainable Development Goals (SDG). Therefore, research on soil resilience in the agricultural environment is crucial for sound and sustainable soil management, especially in highly uncertain and unpredictable conditions. Soil resilience is defined in different ways by several researchers; however, its definition typically includes the concepts of recovery and resistance to stress. The physical, chemical, and biological characteristics of soils that are used to assess the soil resilience, i.e., the response of soil to various types of stress are summarized in this study. In addition, various statistical processing techniques and quantification methods are summarized considering the wide spatial and temporal scope of soil resilience research. Several soil resilience studies typically conduct the following five steps: (1) soil and site selection (2) stress (independent variable) setting (3) soil characteristics and indicator (dependent variable) setting (4) performing various spatiotemporal scale experiments (5) statistical analysis. The previous and present studies present a general introduction of soil resilience, based on which, further practical research considering domestic agricultural environment should be conducted. The extensive range of soil resilience measurements will require collaboration between researchers in various fields.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.3
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• pp.261-269
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• 2014

Most areas in Gangwon-do are mountainous regions where causes heavy damages due to landslides. It is important to analyze basic factors influencing the cause of landslides in order to prevent such landslides. For this study, a landslide occurring site is extracted from aerial images taken after the landslide caused by typhoon 'Ewiniar' in Pyeongchang area 2006. Also, the overlay analysis with the topographic, forest, and soil maps in this area is performed using GIS based methods. In addition, the topographic, forest, and soil characteristics relating to the landslide factors are analyzed. As a result, large numbers of landslides occurred at a slope angle of $20^{\circ}-40^{\circ}$. In the case of the forest factors, there are close relationships between the artificial pine and larch forests and the frequency of landslides. The low forest density represents a weakness in landslides. In the case of the soil factors, a higher level in the surface soil with a type of sandy loam soil, a higher gravel content in subsoil, and a higher degree of acid rocks in soil parent materials cause higher frequencies in landslides.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.2
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• pp.192-197
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• 2009

This study was conducted to investigate the effect of site-specific variable fertilization following digital fertility map generated from soil analysis on rice growth and yield. The site-specific application of fertilizer was implemented by using rice transplanter equipped with side dressing applicator and global positioning system (GPS). Coefficient of variation (C.V.) of soil nitrogen content was reduced after the experiment, and spatial variation of semivariogram was reduced. Rice growth from tillering to ripening stage, plant height, tiller and panicle number increased at site-specific variable fertilization treatment, and coefficient variation (C.V.) of each growth characteristics was lower than those of conventional fertilization treatment. As a result, fertility in the rice field was more uniform become of site-specific fertilizer application. Head rice yield of site-specific application plot increased by 9% (i.e., to from 450 kg/10a to 492 kg/10a of the control plot) and its CV was significantly reduced to 3.5 compared to 7.8 of the control plot. In addition, there was no significant difference in amylose, protein contents and whiteness of milled rice, but its CV was reduced.