• Horticultural Science & Technology
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• v.34 no.6
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• pp.807-817
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• 2016

Many onion growers and researchers assert that differences in soil type, agricultural practices, weather, and duration of prolonged onion cultivation in a particular field could affect onion bulb quality. This study evaluates the bulb quality of onions grown in different regions and determines the correlations between bulb characteristics and postharvest loss during cold and ambient storage. Soil and onion bulbs were collected from fields in six onion growing regions in Korea, during the growing season of 2011-2012. The fresh weight, dry matter content, and carbon (C), sulfur and magnesium contents of the onion bulbs were significantly affected by the location in which they were grown. Bulbs grown in Muan had the greatest number of scales, thinnest scale thickness, and the highest total soluble solids (TSS) and total flavonoids (TF). Bulbs originating from Jecheon had the lowest pyruvic acid (PA), total phenolics and TF. Storage loss of bulbs from the different regions was similar in refrigerated storage, but differed in ambient temperature storage. Bulb fresh weight was positively correlated with scale thickness (r = 0.617) and cold storage loss (CSL; r = 0.398). Dry matter content was positively correlated with C (r = 0.958) and TF (r = 0.256) contents, while it was negatively correlated with CSL (r = -0.424). CSL was primarily affected by the fresh weight, as well as the dry matter, C, and PA contents of the bulbs, while ambient storage loss was primarily influenced by the amount of TSS.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.479-488
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• 2005

Geopier soil reinforcement system which crushed aggregate is put into a hole and rammed the aggregate with tamper is a viable alternative to deep foundation to over-excavation and replacement. Also, Geopier is intermediate foundation of deep and shallow foundation. In this paper, the value of Geopier element stiffness modulus($K_g$) when designed is compared with the measured value($K_g$) by the in-situ modulus Load test in the field. Also, this paper presents a technology overview of system capabilities and application for foundation reinforcement of structures.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.357-362
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• 2000

This Paper presents dynamic analysis of underground R/C Subway Structure, subjected to seismic actions. Earthquakes brought serious damage to RC subway Structure. Foe studying the collapse mechanism of underground RC Subway, seismic of a subway station is simulated in using FEM program ASP2000 of two-dimension based on the path dependent RC elastic model, soil foundation and interfacial models. The shear failure of intermediate vertical columns is founds to be the major cause of the structural collapse. According to FEM simulation of the failure mechanism, it is considered that the RC column would lose axial load carrying capacity after the occurrence of the localized diagonal shear cracks , and sudden failure of the outer frame would be followed. Specially, the shear stress in the middle slab reaches maximum shear capacity. So, the Structure would fail in the middle slab as a result of erasing the vertical ground motion computation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.2
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• pp.64-72
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• 1995

A series of cubical triaxial tests with three independent principal stresses was per- formed on Baekma river sand( # 40~100). It was found that the major principal strain at failure remained approximately constant for b values larger than about 0.3 for both the drained and undrained condition, and thereafter increased as b value decreased. The test results showed that the direction of the strain increment at failure form acute angles with the failure surfaces for both the drained and undrained condition. The results were thus not in agreement with the normality condition from classic plasticity theory. Howev- er, it was found that the projections of the plastic strain increment vectors on the octahe- dral plane were perpendicular to the failure surface in that plane. Failure strength in terms of effective stress anlaysis was greatly influenced by the variation of intermediate principal stress and so was failure criterion. The effective stress failure surfaces for both the drained and undrained condition were estimated quite well by use of Lade's failure criterion.

• Journal of the Korean GEO-environmental Society
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• v.14 no.1
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• pp.33-42
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• 2013

In this paper, a series of monotonic undrained shear tests were carried out on four kinds of sand-fine mixtures with various fines content. Two kinds of sands (Silica sand V3, V6) and fines (Iwakuni natural clay, Tottori silt) were mixed together in various proportions, while paying attention to the void ratio expressed in terms of sand structure $(F_c{\leq}F_{cth})$. The undrained shear strength of mixtures below the threshold fines content was observed so that as the plastic fines content increases, maximum deviator stress ratio decrease for dense samples while an increase is noted for loose samples. For non-plastic fines, the increase in the amount of fines leads to an increase in density of the soil, which results in an increase in strength. Then, the monotonic shear strength of the mixtures was estimated using the concept of granular void ratio. It was found that the shear strength of mixtures is greatly dependent on the skeleton structure of sand particles.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.3
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• pp.97-106
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• 2000

The study is closely relevant to Lade's single work hardening model. This model has been shown to have good applicability to cohesive soils. However the validation of this model on the clayey soils has not been satisfactorily reported. To scrutinize the applicability of this model on clayey foundation the laboratory tests for Kwangyang clayey soils were performed using the improved cubical triaxial test apparatus designed originally by Lade. A computer program was developed by which soil parameters for the single work-hardening model can be rationally determined by deleting some dispersed test data generated usually at the initial stage of laboratory tests. And using the program numerical analysis of the cubical clayey specimens using intermediate principal stress was carried out and a good agreement between observed values and numerical results was found.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.35-43
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• 2015

To assess the dormancy associated weedy risk of the F1 hybrid generated by hybridization between Brassica juncea (maternal) and Brassica napus (paternal), seed germination, dormancy and longevity were examined sequentially after seed harvest. The F1 hybrids exhibited the intermediate characteristics of their parents in seed germination and dormancy with relatively high dormancy rate of 41.1%. In summer, F1 hybrid seeds buried in the 3 cm soil exhibited greater viability (52.4%) than those in the soil surface with greater seed longevity (74.6%) than its maternal (63.3%) and paternal (33.7%) parents at 100 days of over-summering in soil. In winter, F1 seeds buried in the soil surface were more viable than those in the 3 cm soil with greater seed longevity (83.5%) than its maternal (39.0%) and paternal (71.7%) parents at 100 days of over-wintering in soil. Therefore, it is concluded that F1 hybrid resulted from gene flow from OSR to mustard has high seed dormancy and longevity during summer and winter, suggesting its weedy risk potential. Further studies are required to examine the reproductivity and fitness cost of F1 hybrid to make a clearer conclusion of its weedy risk.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.2
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• pp.159-166
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• 2011

This experiment was carried out to investigate the effect of application of swine slurry (SS) and slurry composting-biofilteration liquid fertilizer (SCB) on productivity of sorghum${\times}$sorghum hybrid (SSH) and soil environment in reclaimed land of Sukmoon in Korea. Dry matter (DM) yields of SSH in the treatments of SS and chemical fertilizer (CF) were higher than those of in SCB treatment in reclaimed land, but DM yields in SS and CF did not show a significant difference as compared to SCB. Nutritive values of SSH were not different among CF, SS and SCB. In soil samples collected at the end of the experiment, the concentration of organic matter was significantly increased by SS and SCB as compare to that at the beginning of the experiment (P<0.05), whereas the concentration of total nitrogen was not affected by SS and SCB. To investigate the moisture content of soil, the soils were collected from three layers; surface (0~5 cm), intermediate (10~15 cm), and deep (20~25 cm) layer. The moisture contents of soils increased according to the soil depth and the soil moisture was immediately affected by the amount of rainfall. Therefore, we suggest that the cultivation of SSH using SS in reclaimed land is possible and that additional nitrogen fertilizer was surely applied in case of application of SCB to cultivate SSH.

• Korean Journal of Remote Sensing
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• v.39 no.2
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• pp.233-246
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• 2023

In terms of understanding the water cycle and efficient water resource management, the importance of soil moisture has been highlighted. However, in Korea, the lack of qualified in-situ soil moisture data results in very limited utility. Even if satellite-based data are applied, the absence of ground reference data makes objective evaluation and correction difficult. The cosmic-ray neutron probe (CRNP) can play a key role in producing data for satellite data calibration. The installation of CRNP is non-invasive, minimizing damage to the soil and vegetation environment, and has the advantage of having a spatial representative for the intermediate scale. These characteristics are advantageous to establish an observation network in Korea which has lots of mountainous areas with dense vegetation. Therefore, this study was conducted to evaluate the applicability of the CRNP soil moisture observatory in Korea as part of the establishment of a Korean cOsmic-ray Soil Moisture Observing System (KOSMOS). The CRNP observation station was installed with the Gunup-ri observation station, considering the ease of securing power and installation sites and the efficient use of other hydro-meteorological factors. In order to evaluate the CRNP soil moisture data, 12 additional in-situ soil moisture sensors were installed, and spatial representativeness was evaluated through a temporal stability analysis. The neutrons generated by CRNP were found to be about 1,087 counts per hour on average, which was lower than that of the Solmacheon observation station, indicating that the Hongcheon observation station has a more humid environment. Soil moisture was estimated through neutron correction and early-stage calibration of the observed neutron data. The CRNP soil moisture data showed a high correlation with r=0.82 and high accuracy with root mean square error=0.02 m³/m³ in validation with in-situ data, even in a short calibration period. It is expected that higher quality soil moisture data production with greater accuracy will be possible after recalibration with the accumulation of annual data reflecting seasonal patterns. These results, together with previous studies that verified the excellence of CRNP soil moisture data, suggest that high-quality soil moisture data can be produced when constructing KOSMOS.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.277-294
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• 2012

The characteristics of temporal spacial radon variation in soil according to parent rock type and affecting factors were studied in Busan, Korea. The concentration of $^{222}Rn$ in soils and their parent elements ($^{226}Ra$,$^{228}Ra$, U and Th) in rocks and soils were measured at 24 sites in Busan area. The distribution and transportation behavior of these parent elements were analyzed and their correlations to radon concentration in soil were determined. Topographic effects were also evaluated. Two in-situ radon measurement (soil probe and buried tube) methods were applied to measure radon concentration in soil and their accuracies were evaluated. The spatial variation of radon in soil generally reflected U concentration in the parent rock. Average radon concentrations were higher in plutonic rocks than in volcanic rocks and were decreased in the order of felsic>intermediate>mafic rock. However, the radon concentrations were significantly varied in soils developed from same parent rocks due to the disequilibrium of U and $^{226}Ra$ between rock and soil. As results, the correlation of these element concentrations between rocks and soils was very low and radon concentrations in soils had highly co-related to the concentrations of these elements in soils. Th and $^{228}Ra$ show complex enrichment characteristics, differing significantly with U, in soils developed from same parent rock because the geochemical behavior of these elements during weathering and soil developing process was different with U. The radon concentrations in the same depth of soil in slope area were also different according to positions. The radon concentrations in soils developed from same parent rocks (19 sites at Pusan National University) varied 6.8~29.8Bq/L range because of small scale topographic variation. The opposite seasonal variation pattern of radon were observed according to soil properties. It was determined that buried tube method is more accurate method than soil probe method and was very advantageous application for the analysis for the characteristics of temporal spacial radon variation in soil.