• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.242-247
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• 1988

To elucidate the relationship of the quality of aromatic tobaccos to their chemical constituents, certain chemical components and leaf quality by price were compared among cured leaves produced under different soil moisture levels during growing season. As the soil moisture increased, plant height and the length and width of largest leaf increased. days to flower was shortened and total chlorophyll and carotenoid content of green leaf decreased. As the soil moisture increased, leaf quality was deteriorated. The content of nicotine, pet. ether ext. and total nitrogen increased with slight increment of nonvolatile organic acids and higher fatty acids, but ash content and pH of cured leaves decreased under high soil moisture content. Volatile organic acids such as 3-methyl pentanoic acid, the main compounds contributing to the aroma of oriental tobacco, and most volatile neutrals decreased conspicuously under high soil moisture. The content of pet. ether ext., volatile organic acids, volatile neutrals, ash and pH of cured leaves were found to be the appropriate factors for the quality evaluation of aromatic leaves grown under under different soil moisture.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.6
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• pp.9-13
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• 2002

This study has been performed to investigate the physical and mechanical characteristics of compaction, volume change and compressive strength for reinforced soil mixed with cement. And confirm the reinforcing effects with admixture such as cement. To this end, a series of compaction test and compression test was conducted for clayey soil(CL) and cement reinforced soil. In order to determine proper moisture content and mixing ratio, pilot test was carried out for soil and cement reinforced soil. And the mixing ratio of cement admixture was fixed 3%, 6%, 9% and 12% by the weight of dry soil. As the experimental results, the maximum dry unit weight(${\gamma}_{dmax}$) was increased with the mixing ratio and then shown the peak at 10% reinforced soil, but the optimum moisture content(OMC) and the volume change was decreased with the ratio increase. And the compressive strength volume change was decreased with mixing ratio increased.

• Journal of Wetlands Research
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• v.20 no.1
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• pp.27-34
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• 2018

Reproductive phenology and physiological responses of Epilobium hirsutum L. to moisture content and nutrient content of soil were analysed in order to obtain basic data for effective conservation and restoration. Epilobium hirsutum L. is a perennial plant. But Epilobium hirsutum L. grew reproductively in all moisture and nutrient gradients. Flower bud, flowers and peduncle were respectively ripened in earlier under highest moisture condition and highest nutrient condition. And, number of flowers and peduncle were more quickly increased under highest moisture condition and highest nutrient condition. Chlorophyll content was high under highest moisture condition and higher middle moisture condition. However, we found no significant difference of chlorophyll content regard to nutrient gradients. There was no difference in minimum chlorophyll fluorescence among all moisture and nutrient gradients. The photochemical efficiency values of PS II were 0.75 in all moisture gradients, and it was 0.78 in highest nutrient gradient. The chlorophyll content of Epilobium hirsutum L. increased as the moisture content increased, and the Fv/Fm value increased as the organic matter increased. Our results showed that high moisture and nutrient content of soil advance their breeding season and promote reproductive growth. It might be important basic informations for the maintenance of population and the management of habitat of Epilobium hirsutum L. an endangered plant species.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.399-404
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• 2014

Soil moisture is an important factor for the availability and circulation of nutrients in arable soil. The purpose of this study was to set thresholds moisture content on soil nitrate concentration in the solution for real-time diagnosis. Sandy loam, silt loam, and sandy loam was filled with $1.2g\;cm^{-3}$ at Wagner pots, 0, 100, and $200mg\;L^{-1}$ of $KNO_3$ was saturated. Nitrate in standard solution was recovered about 95% by passing the porous cup. Nitrate concentrations in sampling of soil solution were examined by using a porous cup. The soil solution was higher in accordance with sandy loam> silt loam> clay loam, limited water filled pore space for sampling soil solution was 33.7, 56.4, and 62.2%, respectively. Nitrate concentration in the soil solution was negligible at sandy loam and silt loam during sampling periods, which was decreased about 50~82% in clay loam compared to the initial $NO_3$-N concentration in the saturated $KNO_3$ solution. Over limitation of soil solution sampling, soil EC and $NO_3$-N content were increased with the saturated $NO_3$-N concentration, regardless of soil texture (p<0.05). Conclusively, soil solution by using a porous cup was possible, regardless of the soil texture, which was useful for the diagnosis in nitrate concentration of soil solution. However, because nitrate concentration of soil solution in a clay loam changes, it was necessary for careful attention in order to take advantage for the real-time diagnosis of nitrogen management in soil.

• Magazine of the Korean Society of Agricultural Engineers
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• v.33 no.2
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• pp.82-93
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• 1991

The objective of this paper is to show that the soil-geotextile interaction needs to he addressed in addition to the usual tensile and modulus properties when the geotextile is being designed for a specific application. The soil-geotextile interaction can be directly assessed by standard direct shear test. The data presented here show that the shear strength paramaters describing the soil-geotextile interface can he greatly influenced by the type of the geotextile. In this investigation, we examined nine different geotextiles of varying construction and surface textures with two standard soil, under five loading conditions, and compared the shear strength and the frictional resistance with the corresponding values of soil itself The following conclusions were drawned from this study. 1. The shear stress-strain curve shows that there are the residual shear stresses at the soil-geotextile interface. Because of the hydraulic gradient between the soil and the geotextile, the excessive pore water can migrate into the geotextile and among the filaments and dissipate through the soil-geotextile interface. 2. The shear strength of the soil-geotextile interface is affected by the moisture content of the soil. At moisture content lower than the optimum water content of the Proctor compaction test, the shear strength of the soil-geotextile interface is greater. 3. The type and surface roughness of the geotextile have the greatest influence on the interface friction angle between the soil and the geotextile.

• Korean Journal of Plant Resources
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• v.13 no.2
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• pp.95-103
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• 2000

To study the effects of soil moisture and texture on characteristics of growth, content of saikosaponins and activity of antioxidative enzymes in Bupleurum falcatum L., content of saikosaponins(a, c and d) and activities of superoxide dismutase(SOD) and peroxidase(POD) were investigated with two Bupleurum genotypes(Jangsoo and Samdo). Two Bupleurum genotypes were grown under different soil moisture(deficit, normal, surplus) and soil texture(sandy, sandy loam, loam) conditions. Among the tested soil conditions, dry weight accumulation rate of both cultivars could be ranked in the order surplus > normal > deficit soil for soil moisture and sandy > sandy loam > loam for soil texture. Under the surplus soil condition, growth retardation of Samdo cultivar was more severer than that of Jangsoo. Furthermore, content of saikosaponin a, d, and c also could be ranked in the order deficit > normal > surplus and sandy > sandy loam > loam for soil moisture and texture, respectively. Although both Jangsoo and Samdo cultivars grown under water deficit condition showed the highest POD and SOD activity, in general POD and SOD activity in both shoot and root was remarkably high in Jangsoo cultivar compared with Samdo. Saikosaponin content of root was positively correlated with POD and SOD. However, shoot and root length were negatively correlated with POD.

• Geomechanics and Engineering
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• v.23 no.3
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• pp.227-244
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• 2020

Earthen structures have an excellent bioclimatic performance, but they are vulnerable against earthquakes. In order to investigate the edification process and costs, a full-scale rammed soil house was constructed in 2004. In 2016-2019, it was studied its seismic damage, durability and degradation process. During 2004-2016, the house presented a relatively good seismic performance (M_w=5.6-6.4). The damaged cover contributed in the fast deterioration of walls. In 2018 it was observed a partial collapse of one wall due to recent seismicity (M_w=5.6-6.1). The 15-year-old samples presented a reduced compressive strength (0.040 MPa) and a minimum moisture (1.38%). It is estimated that the existing house has approximately a remaining 20% of compressive strength with a degradation of about 5.4% (0.0109 MPa) per year (considering a time frame of 15 years) if compared to the new soil samples (0.2028 MPa, 3.52% of moisture). This correlation between moisture and compressive strength degradation was compared with the study of new soil samples at the same construction site and compared against the extracted samples from the 15-year-old house. At 7-14-days, the specimens presented a similar compressive strength as the degraded ones, but different moisture. Conversely, the 60-days specimens shown almost five times more strength as the existing samples for a similar moisture. It was observed in new rammed soil that the lower the water content, the higher the compressive/shear strength.

• Journal of Biosystems Engineering
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• v.28 no.1
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• pp.1-10
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• 2003

A computer simulation was carried out to determinate the optimum capacity of bulk type trailer which is used as a tractor attachment. Soil physical properties. such as soil moisture content. bulk density, soil hardness and soil texture were measured in the 10 major rice production area for computer simulation. Mathematical model which include soil physical properties and vehicle factor was used for computer simulation. Most of the soil texture of the investigated area was silty loam. Soil moisture content ranged between 30 and 40% mostly. Soil bulk density was in the range of 1.500 to 1.700 kg/㎥. Soil hardness ranged between 1 to 18 kg/$\textrm{cm}^2$. Soil hardness incorporate the effects of many soil physical properties such as moisture content texture and bulk density, and so the range of soil hardness was greater than any other physical properties. The capacity of bulk type trailer was above 3000 kg$_{f}$ fer the most of the investigated area. and mostly in the range of 4000 to 6000 kg$_{f}$ depending upon the slip. But for the soft soil area such as Andong and Namyang. tractor itself had mobility problem and showed minus trailer capacity for some places. For this area. the capacity of bulk type trailer ranged between 1000 and 2000 kg$_{f}$ mostly so bulk type trailer should be designed as a small capacity compared to the other area.ared to the other area. area.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.8-13
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• 2021

The study for soil has been conducted separately by several areas such as soil mechanics and soil chemistry. Soil is important in terms of prediction of how the plant grow with nutrient requirement. Also, soil is important for machines to work on to solve labor shortage and save farmers from harsh environment during farm work. To meet diverse needs related to soil in agriculture, the soil related study needs to be conducted synthetically. Thus, we tried to obtain the data related to soil chemistry including pH and Electrical Conductivity (EC) with data related to soil mechanics including Cone Index (CI), moisture content, soil classification. Specifically, the condition of the field was set to be cultivated at least for five years continuously at a first step. The soil was taken from 30 sites. CI was obtained using the soil penetrometer and soil classification was conducted using sieve analysis with eight kinds of sieve. The soil was taken on December when is during winter in Korea. There was variation of data including moisture content and CI.

• The Korean Journal of Ecology
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• v.28 no.1
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• pp.25-29
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• 2005

This study was carried out to analyze the soil properties of Lepista nuda habitats to form a part of the studies on the characteristics of L. nuda. The soil samples collected from seven studied areas were investigated for soil properties such as soil moisture, soil pH, and the contents of organic and inorganic matters. The content of soil moisture was 29.7% and the content of organic matter was 32.1%. Total nitrogen was 0.74% and soil pH was 4.75, which was ranged from 3.6 to 5.20. In the content of inorganic matter, the content of Fe was highest as 1,024 ppm, K 183 ppm, Mn 21.9 ppm, Ca 2.02 ppm, Zn 1.46 ppm and Mg was lowest as 0.51 ppm.