• Korean Journal of Soil Science and Fertilizer
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• v.7 no.1
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• pp.1-4
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• 1974

The application of the Distribution Law to soil-pesticide systems yielded the following empirical implications : 1) The amount of the pesticide adsorbed by a soil is negatively proportional to the soil water content. 2) At a given soil water content the amount adsorbed is proportional to the Kd of the soil. 3) The effect of soil water content on the amount of the pesticide adsorbed diminishes with increasing magnitude of the Kd.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.316-316
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• 2017

The objective of this study is to estimate quantitatively soil salinity and soil loss at upland soils in agriculture land region in Saemangeum reclaimed land on the south Korea coasts. Soil loss and soil salinity are the most critical problem at reclaimed tidal saline soil in Korea. The several thematic maps of research area such as land cover map, topographic and soil maps, together with tabular precipitation data used for soil erosion and soil salinity calculation. Meteorological data were measured directly as air temperature, wind speed, solar radiation, and precipitation. The experiment was conducted 2% sloped lysimeter ($5.0m{\times}20.0m$) with 14 treatments and it were separated by low salinity division (LSD) and high salinity division (HSD) install. The cation content in ground water increased during time course, but in the case of land surface water the content was variable, and $K^+$ was lower than that of $Na^+$ and $Mg^{2+}$. At the LSD under rainproof condition, the salinity was directly proportional to soil water content, but at the HSD the tendency was no reversed. In condition of rainproof, the amount of soil salinity was higher at the HSD than at the LSD. Positive correlation was obtained between the soil water content and available phosphorous content at the rainfall division, but there was no significance at the surface soil of the rainproof division. Sodium adsorption ratio and anion contents in soil were repressed in the order of vinyl-mulching > non-mulching > bare field. According to the result of analyzing soil loss, soil loss occurred in a vinyl-mulching, a non-mulching and a bare field in size order, and also approximately 11.2 ton/ha soil loss happened on the reclaimed land area. The average soil loss amount by the unit area takes place in a non-mulching and bare field a lot. Our results indicate that soluble salt control and soil erosion are critical at reclaimed tidal saline soil and the results can provide some useful information for deciding management plans to reduce soil loss and salt damage for stable crop production and diverse utilization or cultivation could be one of the management options to alleviate salt damage at reclaimed tidal saline soil in Korea.

• The KSFM Journal of Fluid Machinery
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• v.19 no.3
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• pp.29-32
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• 2016

A series of laboratory tests were conducted to investigate the geotechnical engineering characteristics of muskeg soil for construction machinery widely distributed in cambridge region in Canada which makes problems in construction works. Physical characteristics of cambridge region muskeg soil were measured in terms of such categories as nature water content, organic content, specfic gravity, liquid limit, and plasticity index. As the test result, it was found that nature water content, organic content, specific gravity, liquid limit, plasticity index, and compression strength were 50.8~343.8%, 12.1~42.5%, 1.76~2.57, 46.6~440.2%, 25.6~280.5, $0.665{\sim}1.537kg/cm^2$, respectively.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.607-616
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• 2006

More strict construction control of railway roadbeds is demanded in high speed railway system because of heavier repeated dynamic loading than conventional railways. The aim of this study is to propose a compaction control methodology of crushed-rock-soil-fills including as large particles as $200\sim300mm$ in diameter, which are easily encountered in high speed railway roadbed. Field tensity evaluation and in turn compaction control of such crushed-rock-soil-fills are almost impossible by conventional methods such as in-situ density measurements or plate loading tests. The proposed method consists of shear wave measurements of compaction specimens in laboratory and in-situ measurements of fills. In other words, compaction control can be carried out by comparing laboratory and field shear wave velocities using as a compaction control parameter. The proposed method was implemented at a soil site in the beginning and will be expanded to crushed-rock-soil-fills in future. One interesting result is that similar relationship of shear wave velocity and water content was obtained as that of density and water content with the maximum value at the optimum moisture content.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.297-306
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• 2019

Soil moisture monitoring is an important task to cope with climate change, and soil water prediction can provide large-scale soil moisture information. Therefore, this study was conducted to evaluate the relationship between the measured and predicted soil water content, and to estimate the correlation between the soil characteristics and soil water content. The selected sites in soil moisture monitoring network were 76, and the soil with high sand content (sand, loamy sand, and sandy loam in soil texture) accounted for 77% of the total. Organic matter and bulk density were 0.03 to 3.50% and 1.01 to 1.69 Mg m^-3, respectively. Predicting values of field capacity and wilting point were lower than the measured soil water content, and the correlation coefficient between the measured and predicted values were low as 0.548 to 0.748. However, a significantly high positive correlation (p<0.01) found between the measured and predicted soil water content. Soil water (field water capacity and wilting point) content was highly positively correlated with silt, clay, and organic matter (p<0.01) and highly negatively correlated with sand (p<0.01).

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.302-305
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• 2003

The electrokinetic remediation tests for natural soil contaminated by lead are performed on unsaturated conditions, in which the degree of saturation is controlled through the changes in water content and the constant unit weight. At the degree of saturation of 70% the small acid range and electrical potential is developed. The changes in the water content are little above the saturation of 90%. But it is increased by 1.7 times at the degree of saturation of 70%. Finally, the efficiency of extraction is improved at 70% than 100%.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.2
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• pp.3778-3783
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• 1975

The objective of this study is to determine an appropriate cement of soil-cement in which silty soil of salty tidal flat with low plasticity was used. Physical, chemical and mechanical tests were conducted to find out the standard properties of the soil to be used. Various cement contents used in this test were 8%, 10%, 12%, and 14%, and the compressive strength was tested after 7 days and 28 days of standard curing in the above each cement content respectively. The results obtaind are summarized as follows. 1. As the cement content was increased from 8% to 14%, Maximum dry density (M.D.D.) and optimum moisture content (O.M.C.) were not changed remarkably. 2. Density of soil-cement was directly proportional to cement content and inversely proportional to water content. 3. OMC was generally decreased in proportion to the increase of cement content. 4. Compressive stranth was directly proportional to centent and inversely proportional to water content. 5. In freezing and thawing test, maximum loss of 10% in the total Weight was found on the 8% cement mixture. and This loss was rapidly decreased to 2% when the Cement content of the mixture was more than 10%.

• International Journal of Highway Engineering
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• v.7 no.4 s.26
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• pp.103-112
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• 2005

Water content of sub-layer in pavement systems has a large effect on pavement performance. Many researchers lately make use of time-domain reflectometry(TDR) probes to measure the soil water content of sub-layer from field monitoring. The laboratory calibration test of TDR probe should be performed with soil field, because TDR probe can cause an error by type, gradation, density, and temperature of soil. This study performed the laboratory calibration test of TDR probe(CS616) with subgrade and subbase material in long term pavement performance(LTPP) sections. And the calibration equations of TDR probe(CS616) were then proposed. It was confirmed from the study that the data of TDR probe monitored in field could be used to estimate the freezing, unfrozen water content, and matric suction of soil.

• Journal of Ecology and Environment
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• v.45 no.1
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• pp.17-23
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• 2021

Background: Montane wetlands are unique wetland ecosystems with distinct physicochemical characteristics, and Molinia japonica often makes dominant communities in montane wetlands in South Korea. In order to figure out the environmental characteristics of M. japonica habitats and the major factors for the growth of M. japonica, field surveys were conducted in five wetlands from September to October 2019. Also, soil was collected at every quadrats installed in surveyed wetlands to analyze the physicochemical features. Results: The relative coverage of M. japonica was higher in low latitude wetlands than in high latitude. Redundancy analysis showed that soil water content had the strongest effect on the growth of M. japonica (F = 23.0, p < 0.001). Soil water content, loss on ignition, and relative light intensity showed a high correlation with the density (R = 0.568, 0.550, 0.547, respectively, p < 0.01) and the coverage of M. japonica (R = 0.495, 0.385, 0.514, respectively, p < 0.01). Soil water content, loss on ignition, and pH were highly correlated with each other. Conclusions: Molinia japonica lives in acidic wetlands at high altitude in temperate zone of low latitude, with peat layer placed on the floor. Also, M. japonica prefers open spaces to secure enough light for photosynthesis. High shoot production of M. japonica resulted in adding new peat material in every year, and this layer enforces the environmental characteristics of M. japonica habitats. This study may provide insights for further understanding of the method how wetlands maintain acidic condition by itself in montane wetlands in temperate zone.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.651-656
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• 1999

This study was carried out to investigate the paddy soil and water quality in Boryung freshwater reservoir watershed during the non-cropping season. Soil pH of the Boryung freshwater reservoir watershed were 5.39∼5.78. Total-N and P contents were high by the accumulation of chemical fertilizer partly. Heavy metal content of paddy soils were natural background level. Water pH of the Boryung freshwater reservoir watershed ranged from 6.82 to 8.64. Total-N content affected by a livestock wastes and sewage water were the higher than that of others and total-P content showed below 0.1mg/L. Nitrate nitrogen contents was very high according to the influence a livestock waste and sewage water partly. Heavy metal contents of wateers were natural background level.