• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.79-84
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• 2000

The aim of this study was to evaluate the chemical properties of orchard soils through which their soil fertilities were discriminated. Total 877 soil samples in major orchard area, i.e. from 239 apple, 369 pear, 168 grape, 101 peach orchards, were examed on the basis of temporary optimal range for each component. The levels of fertility were ranged from 3.0 to 65.2% compared to optimum fertility, suggesting that almost orchard soils contained inadequately soil components. The contents of chemical component have a tendency to decrease with soil depth gradually from surface to subsoil. This meaned that the contents of various components in subsoil could be estimated on the basis of analysis of surface soil, using the linearly fitted equations of the relationship between component in subsoil and in surface at least to which fertility were samely managed. Furthermore, even when only the content of components in 20cm depth surface soil was analyzed, it could be determined whether the amount of each component in the surface soil is surplus or deficient.

• Journal of electromagnetic engineering and science
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• v.10 no.4
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• pp.212-218
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• 2010

The radar backscatter from various earth surfaces is sensitive to the frequency of the incident wave. This study examined the radar sensitivities for surface parameters such as soil moisture content and surface roughness of both bare and vegetated surfaces at X-band. Because L-band frequencies are often used for sensing the surface parameters, the sensitivities of X-band are also compared with those of the L-band. The sensitivities of the X-band radar backscatter were examined with respect to soil moisture content and surface roughness of rough bare soil surfaces. These sensitivities were also examined using the same parameters for vegetated surfaces for various vegetation densities and incidence angles. Use of the X-band radar for soil moisture detection was as effective as L-band radar for bare soil surfaces. For vegetated surfaces, the soil moisture could be detected using an X-band radar at lower incidence angles, where the upper limit of the incidence angles was dependent on vegetation density.

• Korean Journal of Remote Sensing
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• v.30 no.3
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• pp.375-381
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• 2014

Soil moisture is an essential satellite-driven variable for understanding hydrologic, pedologic and geomorphic processes. The European Space Agency (ESA) has endorsed soil moisture as one of Climate Change Initiates (CCI) and had merged multi-satellites over 30 years. The $0.25^{\circ}$ coarse resolution soil moisture satellite data showed correlations with variables of a water stress index, Temperature-Vegetation Dryness Index (TVDI), from a stepwise regression analysis. The ancillary data from TVDI, Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) from MODIS were inputted to a multi-regression analysis for estimating the surface soil moisture. The estimated soil moisture was validated with in-situ soil moisture data from April, 2012 to March, 2013 at Andong observation sites in South Korea. The soil moisture estimated using satellite-based LST and NDVI showed a good agreement with the observed ground data that this approach is plausible to define spatial distribution of surface soil moisture.

• Journal of Korean Society on Water Environment
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• v.28 no.1
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• pp.137-147
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• 2012

Land surface temperature in ecohydrology is a variable that links surface structure to soil processes and yet its spatial prediction across landscapes with variable surface structure is poorly understood. And there are an insufficient number of soil temperature monitoring stations. In this study, a grid-based land surface temperature prediction model is proposed. Target sites are Andong and Namgang dam region. The proposed model is run in the following way. At first, geo-referenced site specific air temperatures are estimated using a kriging technique from data collected from 60 point weather stations. Then surface soil temperature is computed from the estimated geo-referenced site-specific air temperature and normalized difference vegetation index. After the model is calibrated with data collected from observed remote-sensed soil temperature, a soil temperature map is prepared based on the predictions of the model for each geo-referenced site. The daily and monthly simulated soil temperature shows that the proposed model is useful for reproducing observed soil temperature. Soil temperatures at 30 and 50 cm of soil depth are also well simulated.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.2
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• pp.139-143
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• 2009

We examined the vertical distribution of specific microbial groups and the patterns of microbial community structure within the soil profile using phospholipid fatty acid (PLFA). Samples were collected from the soil surface down to 15 cm in depth from paddy and upland fields located in Daegu, Korea. The two fields have been fertilized with only chemical fertilizers N, P, K for 33 years. Principal component analysis of the PLFA signatures indicated that the composition of the soil microbial communities changed significantly with the cultivation practices and soil depth, suggesting that cultivation practices of paddy and upland fields had more significant influence on soil microbial community than the soil depth did. The soil microbial communities changed more drastically with soil depth in upland field than in paddy field, with making thicker soil surface in paddy field in terms of soil microbial community. The ratios of cyclopropyl/monoenoic precursors and total saturated/total monounsaturated fatty acids increased with soil depth, suggesting that the deeper soil horizons are more carbon-limited and anaerobic than surface soil. The community analysis using PLFAs as biomarkers revealed that Gram-positive bacteria and actinomycetes tended to increase in proportional abundance with increasing soil depth, while the abundance of Gram-negative bacteria and fungi were highest at the soil surface and substantially lower in the subsurface.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.145-150
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• 1999

To estimate the thermal effect of the vegetation canopy on the surface sublayer environment numerically, we used the combined model of Pielke's1) single layer model for vegetation and Deardorff's2) Force restore method(FRM) for soil layer. Application of present combined model to three surface conditions, ie., unsaturated bare soil, saturated bare soil and saturated vegetation canopy, showed followings; The diurnal temperature range of saturated vegetation canopy is only 20K, while saturated bare soil and unsaturated bare soil surface are 30K, 35K, respectively. The maximum temperature of vegetation canopy occurs at noon, about 2 hours earlier than that of the non-vegetation cases. The peak latent heat fluxes of vegetation canopy is simulated as a 600Wm-2 at 1300 LST. They have higher values during afternoon than beforenoon. Furthermore, the energy redistribution ratios to latent heat fluxes also increased in the late afternoon. Therefore, oasis effect driving from the vegetation canopy is reinforced during late afternoon compared with the non-vegetated conditions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.80-81
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• 2013

There is the increasing number of constructing soil or structure on the soft ground during public works. Usually cement or slag cement has been the traditional material for surface soil stabilization method. Recently, early strength development properties of hardening agent is required for driving abilities of execution equipment and shortening of the construction time. Therefore, the purpose of this study is to develop the early compressive strength hardening agent for surface soil stabilization. The study was confirmed performance and availability of hardening agent using early strength type cement and industrial by-product minerals through early strength development properties in accordance with water cement ratio, content of hardening agent for soft soil.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.785-791
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• 2009

Using artificial rainfall simulator, the soil loss, which is deemed as the most cause of muddy water problem among Non-point source (NPS) pollutant, was studied by the analysis of direct runoff, groundwater discharge, and soil water storage properties concerned with rainfall intensity, slope of area, and land cover. The direct runoff showed increasing tendency in both straw covered and bared soil as slope increases from 5% to 20%. The direct runoff volume from straw covered surface were much lower than bared surface. The infiltration capacity of straw covered surface increased, because the surface sealing by fine material of soil surface didn't occur due to the straw covering. Under the same rainfall intensity and slope condition, 2.4~8.2 times of sediment yield were occurred from bared surface more than straw covered surface. The volume of infiltration increased due to straw cover and the direct runoff flow decreased with decrease of tractive force in surface. To understand the relationship of the rate of direct runoff, groundwater discharge, and soil water storage by the rainfall intensity, slope, and land cover, the statistical test was performed. It shows good relationship between most of factors, except between the rate of groundwater storage and rainfall intensity.

• Journal of Korean Society of Forest Science
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• v.107 no.1
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• pp.108-111
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• 2018

Increasing soil surface roughness can be effective in enhancing infiltration of rainfall and depression storage capacity of forest soil and reducing surface run-off. In this study, a forest slope with hemispherical depressions shows greater infiltration of water, whereas depression storage capacity is higher in soil with depressions perpendicular to a water flow pathway. Soil pitting or forming surface depressions can be used as a countermeasure after forest fires and a practical way to reduce drought stress of forest soil.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.535-542
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• 1994

Remote sensing technique is based on the estimation of land surface characteristics from the measurement of the emitted radiation from the earth. The hydrologically related parameters studied using this approach include surface temperature, evapotranspiration, soil moisture, precipitation and snow. This study introduces a method for estimating moisture content of a bare soil from the observed and simulated brightness temperature. In a bare soil, microwave emission depends on moisture content, soil temperature, and surface roughness. The method is based on a radiative transfer model with some modifications of Fresnel reflection coefficient to take into account the effect of surface roughness. One smooth bare field and two fields with different surface roughness are prepared for the study. The results indicate that the effect of surface roughness is to increase the soil's brightness temperature and to reduce the slope of regression between brightness temperature and moisture contents.