• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.1335-1337
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• 2005

• The Korean Journal of Ecology
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• v.16 no.1
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• pp.1-15
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• 1993

Ordination and classification techiques were used to analyze the forest communities and to examine the integration problem of community-to-ecological species group in mt. moak provincial park of korea. phytosociological classiication based on floristic composition produced seven commuities of zelkova serrata, carpinus densiflora. These seven communities were well discriminated in the two-dimensional analyses of soil moisture, soil organic matter content and temperature(elevation), eciprocally, and in three-dimensional space of the three environmental factors also. They corresponded to seven ecological groups derived from the distribution pattern analysis of species populations in this mountain.

• Proceedings of the Korean Society of Crop Science Conference
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• 2004.04a
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• pp.184-185
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• 2004

• Magazine of the Korean Society of Agricultural Engineers
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• v.36 no.4
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• pp.103-116
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• 1994

The objective of this study was to determine the criteria for density and moisture content measurements made with a nuclear density meter on common materials in the construction field. The study also sought to test a full-type nuclear density meter in controlling the density of overlay layers( 2.5~5.0cm). In order to determine the accuracy and reliablility of nuclear guage measurements made on construction materials, laboratory and field tests were conducted. Wooden blocks( 65 x 45 ${\times}$ 50 cm) and a special steel compactor( 4.7kg) were constructed in order to carry out tests which were conducted on three different materials; coarse gramed soil, fine grained soil, and AC material. Throughout all laboratory and field tests, the nuclear density and moisture content were determined using Humboldt 5OOLP nuclear gauge. The tests on subgrade material entailed obtaining density measurements by means of both the sand replacement method and the nuclear density meter. The results of the sand replacement method were then compared to the readings recorded bu the meter. As in the subgrade material tests, density measurements made during AC pavement tests were also determined using the unclear meter in addition to a second means; through the core method. The meter readings and core densties were compared as was done in the tests on subgrade materials. The correlation between the results of the sand replacement test( also, the core method) and meter readings on subgrade material was then determined. Sirnilarly, the observed results were then analyzed through linear regression. The tests to determine thin-lift density by means of a full-type nuclear density meter also conducted on the overlay layers( about 4. 8cm thickness) above AC pavements at road construction sities in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.486-490
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• 2014

This study was conducted to investigate the effect of carbonized biomass from crop residues on soil carbon storage during soybean cultivation. The carbonized biomass was made by field scale mobile pyrolyzer. The treatments consisted of control without input and three levels of carbonized biomass inputs as $59.5kg10a^{-1}$, C-1 ; $119kg10a^{-1}$, C-2 ; $238kg10a^{-1}$, C-3. Soil samples were collected during the 113 days of experimental periods, and analyzed soil pH and moisture contents. Soil carbon contents and soybean yield were measured at harvesting period. For the experimental results, soil pH ranged from 6.8 to 7.5, and then increased with increasing carbonized material input. Soil moisture contents were slightly higher by 0.1~1.5% than the control, but consistent pattern was not observed among the treatments. Soil carbon and organic carbon contents in the treatments increased at 24 and 15% relative to the control at 15 days after sowing, respectively. Loss rate of SOC (soil organic carbon) relative to its initial content was 7.2% in control followed by C-1, 6.8%> C-2, 3.5%>C-3, 1.1% during the experimental periods. The SOC change rate decreased with increasing carbonized biomass rate. It was appeared that soybean yields were $476.9kg10a^{-1}$ in the control, and ranged from 453.6 to $527.3kg10a^{-1}$ in the treatments. However, significant difference was not found among the treatments. It might be considered that the experimental results will be applied to soil carbon sequestration for future study.

• The Korean Journal of Ecology
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• v.27 no.2
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• pp.87-92
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• 2004

Soil respiration rate was measured from March to November 2003 using the KOH absorption method in Pinus densiflora, Quercus variabilis, Platycarya strobilacea stands in Jinju, Gyeongnam Province. Throughout the study period, average soil temperature and moisture content were 16.2$^{\circ}C$, 25.1% for P. densiflora stand, 17.1$^{\circ}C$, 24.3% for Q. variabilis stand, and 17.6$^{\circ}C$, 25.1% for P. strobilacea stand, respectively. The seasonal fluctuations of soil respiration rate increasing in summer and decreasing in winter, which there were strong positive correlations of soil respiration and soil temperature in all study stands. However, there were no significant correlations between soil moisture and soil respiration. Soil respiration rates throughout the study period ranged from 0.12 to 0.77 for P. densiflora stand, 0.23 to 1.37 for Q. valiabilis stand, and 0.30 to 1.47 g $CO_2\cdotm^{-2}\cdothr^{ -1}$ for P. strobilacea stand, respectively. Mean soil respiration rates in P. densiflora, Q. variabilis, P. strobilacea stands were 0.43, 0.80, and 0.90 g $CO_2\cdotm^{-2}\cdothr^{ -1}$, respectively. The Q$_{10}$ values were 2.38 for P. densiflora stand, 2.11 for Q. variabilis stand, and 2.07 for P. strobilacea stand. Annual total soil respiration was 24 for P. densiflora stand, 49.3 for Q. variabilis stand, and 55.3 t $CO_2\cdotha^{-1}\cdotyr^{ -1}$ for P. strobilacea stand, respectively.y.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.1
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• pp.7-12
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• 1977

This experiment was conducted in the laboratory in order to find out the relationships between the root growth and soil physical properties. The soils selected for this study were Sangju sandy loam, Yeongog loam, Hwadong silty clay loam, which have been considered to be a typical upland soils of Korea. Artificial core samples were made with various moisture contents and bulk densities. Elongation rate of pea seedling taproot and soil strength were measured respectively in these core samples. The results obtained are summarized as follows: 1. The soil strength increased with the bulk density and deceased with moisture content. 2. The correlation between root elongation and soil bulk density was significantly recognized at the same moisture content and the root elongation was influenced by the bulk density more significantly at dry condition. 3. The elongation rate of pea seedling taproot was significantly decreased by increasing the strength (Yamanaka tester and Fine probe) of the soils. 4. The soil strength of $21kg/cm^2$ in fine metal probe or 24mm in Yamanaka tester was considered to be the critical point for plant growth, which was restricting root elongation smaller than 1/4 of the maximum growth rate.

• Journal of Korea Water Resources Association
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• v.48 no.10
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• pp.831-843
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• 2015

This study estimates MODIS-derived evapotranspiration data quality by revised RS-PM algorithm in Seolmacheon test basin. We used latent flux with eddy covariance method to evaluate MODIS-derived spatial evapotranspiration and gap-filled these data by three methods (FAO-PM, MDV and Kalman Filter) and to quantify daily evapotranspiration. Gap-filled daily evapotranspiration data was used to evaluate evapotranspiration computed by revised RS-PM algorithm derived MODIS satellite images. For the water budget analysis, we used soil moisture content that is quantified to average individual soil moisture rate observed by TDR (Time Domain Reflectometry) sensor at soil depth. The soil moisture variation is calculated in consideration from initial to final soil moisture content. According to the result of this study, evapotranspiration computed by revised RS-PM algorithm is very larger than eddy covariance data gap-filled by three methods. Also, water budget characteristics is not closed. We could analysis that MODIS-derived spatial evapotranspiration does not represent actual evapotranspiration in Seolmacheon.

• Geomechanics and Engineering
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• v.17 no.2
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• pp.195-206
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• 2019

The gypsiferous soils are significantly sensitive to moisture and the water has a severe destructive effect on them. Therefore, the effect of lime and silica fume addition on their mechanical properties, when subjected to water, is investigated. Gypsiferous soil specimens were mixed with 1, 2 and 3% lime and 1, 3, 5 and 7% silica fume, in terms of the dry weight of soil. The specimens were mixed at optimum moisture content and cured for 24 hours, 7 and 28 days. 86 specimens in the sizes of unconfined compression strength test mold were prepared to perform unconfined compressive strength and durability tests. The results proved that adding even 1% of each of these additives can lead to a 15 times increase in unconfined compressive strength, compared with untreated specimen, and this increases as the curing time is prolonged. Also, after soaking, the compressive strength of the specimens stabilized with 2 and 3% lime plus different percentages of silica fume was considerably higher than before soaking. The durability of the treated specimens increased significantly after soaking. Direct shear tests showed that lime treatment is more efficient than silica fume treatment. Moreover, it is concluded that the initial tangent modulus and the strain at failure increased as the normal stress of the test was increased. Also, the higher lime contents, up to certain limits, increase the shear strength. Therefore, simultaneous use of lime and silica fume is recommended to improve the geotechnical properties of gypsiferous soils.

• Journal of Forest and Environmental Science
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• v.26 no.2
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• pp.117-129
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• 2010

The present study was undertaken in moist temperate forest of Mandal-Chopta area in the Garhwal region of Uttarakhand, India. The aim of the present study was to assess the physical properties of soils in relation to the forest structure and composition. Twelve forest types according to the altitude, slope aspect and species compositions were selected for the study. Physical properties of soil i.e., soil colour, soil texture (per cent of sand, silt and clay), moisture content, water holding capacity, porosity, bulk density (gm/$cm^3$) and void ratio were analyzed for three different depths viz., (i) 'upper' (0-10 cm), (ii) 'middle' (11-30 cm) and (iii) 'lower' (31-60 cm) in all the selected forest types. Phytosociological and diversity parameters viz. total basal cover ($Gha^{-1}$), stem density ($Nha^{-1}$), tree species richness, Simpson concentration of dominance and Shannon-Wiener diversity index were also calculated for each forest type. This study also provides the comparisons between the results of physical analysis of the present study with numerous other previous studies in the temperate Himalayan region of the Uttarakhand.