• Journal of Korean Society on Water Environment
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• v.32 no.2
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• pp.183-190
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• 2016

Monitored data (rainfall runoff and water quality) from 4 different paddy sites over 3 years were compared to analyze the effect of irrigation water management on irrigation supply and rainfall runoff quality in Korea. The system of rice intensification water management was adopted at one site (SRI) while the conventional water management method was used for rice culture at the other three sites (CT, SD and HD). The soil texture at SRI, CT and SD was sandy loam while that at HD was silt loam. The average reduction of irrigation supply at SRI compared with CT, SD and HD during the 3 years studied was 49%, 51% and 55%, respectively. The average event mean concentration (EMC) at SRI compared with that at CT, SD and HD was decreased by 35% (BOD), 44% (COD), 47% (SS), 19% (TN) and 38% (TP). The correlation between rainfall runoff and the measured non-point source (NPS) pollutants was very good in general. The comparison revealed that SRI water management significantly reduced both irrigation supply and EMC in rainfall runoff. Paddy NPS pollution was closely related to factors that induce runoff such as rainfall and irrigation supply. It was concluded that SRI management could be an effective and practical option to cope with both water shortage due to climate change and water quality improvement in rural watersheds. However, further studies are recommended in large irrigation districts for use in the development and implementation of NPS pollution policies since the data was collected from field sized paddies.

• Journal of Korean Society on Water Environment
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• v.27 no.5
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• pp.572-579
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• 2011

We have examined the runoff characteristics of nonpoint source (NPS) in fields. Two monitoring sites were equipped with an automatic velocity meter and water sampler. Monitoring was conducted at fields 1 and field 2 during the rainfall event. Ten rainfall-runoff events were monitored and analyzed during the study period. The results show that runoff occurred if daily rainfall and intensity were higher than 40 mm and 1.6 mm/hr except a few extreme rainfall events with very high intensity. Runoff of field 1 was approximately twice of that of field 2. Event mean concentrations (EMC) and pollution load of analyzed water quality indices were also higher in field 2 than in field 1. Especially, TN load from field 2 was $75.4 mg/m^2$ and was about 5 times higher than that from field 1. Analysis of Pearson correlation coefficient of water quality parameter indicates that besides of TN all items in fields 1 have tight relationship respectively (p < 0.01). But those of fields 2 have a significant (p < 0.05). Estimating units loading of NPS, we suggested that variable such as soil texture, rainfall amount and intensity and slope were needed to be considered from agricultural landuses. The results of this study can be used as a basic data in the development and implementation of total maximum daily loads (TMDL) in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.s01
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• pp.1-17
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• 1988

Rice Quality is considered to the five catagories ; the nutritional value: the characteristics of cooking. eating and processing: grain size, shape and appearance : milling yields: and storage characteristics. Because most rice is processed and consumed in whole-kernel form. the cooking and eating quality is of important and the physical properties of the intact kernel such as size, shape and general appearance are of particular significance in determining marketing quality. Eating Quality which can be directly evaluated by consumer's panel test is so complicate and variable, and thus the objective and simplified method of evaluation is required of using appropriate instruments. Even though many researches have been done to evaluate the eating quality in various aspects such as the texture of cooked rice kernels, amylogram analysis of rice powder, amylose content. gelatinization temperature. moisture absorption of rice kernel, and cooking characteristics, none of them is satisfied for the evaluation of eating quality. The improving eating quality should be also considered to many cultural factors. such as varieties, climatic and soil conditions, cultural method, handling after harvest. milling and storage conditions. In Korea, many researches in grain size. shape and appearance, and eating quality have been done with the varietal improvement mainly by rice breeders, but no effective method of evaluation was established. A few research have been done in the relationship between rice quality and cultural factors. In the future, research in rice quality should emphasize to establish the standard evaluation method in the physicochemical properties of rice kernels for application of varietal selection. and to develop cultural practices for the preserving quality characteristics of the varieties.

• Korea Science and Art Forum
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• v.19
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• pp.601-612
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• 2015

Postmodernism has blurred the line between design and art. We would like to suggest a design case that took diversity in the modern era that harmonizes functionality and shape of the top board of a furniture and trend of the role of furniture and objet into consideration. This study aims to project a new role into space via convergence of objet that has aesthetic function and furniture design that plays practical role in space. Thus, furniture design attempts to combine ceramic and carpentry and demonstrate the value and potential the combination possesses. By creating a distinct design from previous furniture that had visual limitations with ceramic bridge that adopted existing piling method in ceramic design, we expect a fresh blend of furniture and space that encompasses a different sensation from color and texture of soil and glaze, unable to attain from simple wood.

• Journal of the Korean Geotechnical Society
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• v.39 no.6
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• pp.13-19
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• 2023

Lunar ice is a resource available for future human exploration in deep space and long-term extraterrestrial habitat. However, the origin and nature of lunar ice remains unclear. In addition to remote sensing, international space agencies are competitively planning and conducting missions for lunar surface exploration to determine the existence and resource extent of lunar ice. If a sufficient amount of lunar ice is confirmed, its future in-situ resource utilization is expected to be greatly beneficial. However, due to ice extraction, settlement may occur, which should be taken into account from a geotechnical engineering perspective. Herein, experimental investigations of the potential settlement caused by lunar ice extraction were conducted and different textures of lunar ice were simulated. Consequently, it was confirmed that significant settlement occurs even at the initial water content of ~10% in lunar regolith simulant-ice-mixed soil.

• Korean Journal of Soil Science and Fertilizer
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• v.2 no.1
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• pp.15-26
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• 1969

The study on physico-chemical characteristics of the acid sulfate soil present in Kimhae plain was carried out with 28 surface and subsoils from lower and higher produtive area and two representative profile samples from the areas reclaimed a few decades ago and around 10 years ago respectively. 1. There are no differences in soil texture between lower and higher productive soils being mostly silty clay loam and silty clay. 2. Very significant differences in pH, degree of base saturation and extractable aluminium content are observed; lower pH, lower degree of base saturation and higher aluminium in the lower productive soils and subsoils. The pH and degree of base saturation of these soils are extremely low whereas aluminium content is very high compared to ordinary paddy soil. 3. Cation exchange capacity of these soils are slightly higher than ordinary paddy soils. In higher productive soils, exchangeable calcium and magnesium are of same order, whereas in lower productive soils magnesium content is appreciably higher than calcium. 4. Though the soil is derived from marine and estuarine sediment, the soluble salt content is not high. There are only few lower productive surface soils and subsoils having Ec values of the saturation extracts higher than 4 mmhos but lower than 9 mmhos/cm. 5. Organic matter content of these soils is a bit higher compared to ordinary paddy soils, but, nitrogen content is comparatively low. C/N ratio of these soils is around 12. 6. Sulfur content is considerably higher but oxidizable sulfur is found to be very low. Total sulfur is generally high in subsoils and lower productive soils. 7. Active iron and available silica are slightly higher than ordinary paddy soils but easily reducible manganese is very low. Almost no differences are also observed between lower and higher productive soils. 8. Available phosphorus content is extremely low in particular, regardless of higher or lower productive soils. 9. The two representative profiles from the area of earlier reclamation and recent one show that samples from earlier reclaimed area contain less amount of free acids, sulfur compounds, toxic aluminium and soluble salts etc. than the other. This indicate greater leaching and possible addition of lime for a longer period of time. 10. From the results obtained, it can be concluded the higher productivity of group I soils is due to the greater leaching and neutralisation of acidity by liming materials, It can also be concluded that the productivity of both types can be increased by addition of liming materials and improvement of drainage facilities.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.26-37
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• 1992

Fifty-five field experiments were conducted in order to find out some useful indices for the prediction of N-supplying capability(NSC) of soils under cultivation of corn in Pennsylvania over 3 years from 1986. Contents of $NO_3-N$, absorbance at 200 nm of the extract from soil with 0.01M $NaHCO_3$ were identified to be used as indices before planting. Methods for the estimation of organic nitrogen available later in the growing season(KCLA-N, PBBA-N, UV260 nm absorbance of $NaHCO_3$ extract) were not to be used as good indices individually, but when those are combined together with inorganic $NO_3-N$ showed a highly significant correlationship with the NSC. The year of an even distribution of rainfall, 1987, gave the highest significant correlationship between NSC and the indices. For soils of the same texture with slightly different physical properties, combined indices obtained from physico-chemical factors improved the degree of predictability when the grades of soil slope, depth of Ap were considered at the same time. More futher researches such as this need to be done before any conclusive result can be drawn.

• Journal of Environmental Policy
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• v.12 no.3
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• pp.21-47
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• 2013

The aim is to analysis landslide vulnerability in Inje, Korea, using GCI(Geospatial Correlative Integration) and probability rainfalls based on geographic information system (GIS). In order to achieve this goal, identified indicators influencing landslides based on literature review. We include indicators of exposure to climate(rainfall probability), sensitivity(slope, aspect, curvature, geology, topography, soil drainage, soil material, soil thickness and soil texture) and adaptive capacity(timber diameter, timber type, timber density and timber age). All data were collected, processed, and compiled in a spatial database using GIS. Karisan-ri that had experienced 470 landslides by Typhoon Ewinia in 2006 was selected for analysis and verification. The 50% of landslide data were randomly selected to use as training data, while the other 50% being used for verification. The probability of landslides for target years (1 year, 3 years, 10 years, 50 years, and 100 years) was calculated assuming that landslides are triggered by 3-day cumulative rainfalls of 449 mm. Results show that number of slope has comparatively strong influence on landslide damage. And inclination of $25{\sim}30^{\circ}C$, the highest correlation landslide. Improved previous landslide vulnerability methodology by adopting GCI. Also, vulnerability map provides meaningful information for decision makers regarding priority areas for implementing landslide mitigation policies.

• The Korean Journal of Mycology
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• v.39 no.3
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• pp.164-170
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• 2011

Amanita hemibapha is a kind of mycorrhizal mushroom which has a relation with host plants and environmental factors. For the purpose of studying the relationship between environmental factors and mushrooms, in this study we conducted to investigate the soil physicochemical properties, the distribution of plants and the diversity of mushrooms in Gwangyang, Chungdo and Daegu. Soil texture in habitate of Amanita hemibapha was Sandy Loam and Sandy Clay Loam which contains a high rate of sand. Soil pH was approximately 5.0 in all study sites. Total nitrogen contents, C/N ratio and available phosphate($P_2O_5$) were the highest at the Chungdo. However, Gwangyang and Chungdo represent similar Cation Exchange Capacity(C.E.C) and Daegu has much less than other areas. Exchangeable cations, $Ca^{2+}$ content was higher at Gwangyang and Chungdo than Daegu and $Na^+$ content was the highest at Chungdo among three sites. Daegu has much $Mg^{2+}$ contents followed by Chungdo and Gwangyang. Interestingly, $K^+$ content listed in reverse order of $Mg^{2+}$ at Gwangyang, Chungdo and Daegu. The main woody plants in study sites are confirmed as Carpinus laxiflora, Quercus mongolica, Q. serrata and Pinus densiflora. Quercus species are found as a common species in three study sites. Lastly, 8 family and 12 species of mushrooms are emerged in Gwangyang, also 8 family and 12 species and 5 family and 10 species are found in Chungdo and Daegu, respectively. Amanita pantherina, Boletus edulis, Tylopilus felleus and Marasmius maximus, which found in study sites, are also kind of mycorrhizal mushroom same as A. hemibaph. By using correspondence analysis, Q. mongolica, Q. serrata, Q. variabilis and C. laxiflora are expected to as a host plant of A. hemibapha.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.1-7
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• 2010

This study was carried out to investigate plow pan characteristics and to grasp the relationship between its particle size distribution fractal dimension ($D_m$) and water transport in paddy plow pan. Twenty four soil sampling sites with different management groups, ordinary and sandy-textured, were selected and investigated for physical properties of soils such as Yamanaka hardness in April, non-submerged condition, before rice seedling transplanting. The plow pan appearing depth and thickness was determined by penetration resistance profile. Undisturbed core samples with five replicates were sampled at plow pan layerwith 2 inch cores for measuring soil bulk density and saturated hydraulic conductivity. The particle size distribution fractal dimension ($D_m$) was calculated by the method following the procedure Tylerand Wheacraft (1992), using the USDA-based particle size analysis datawith fractions of 0-0.002, 0.002-0.053, 0.053-0.1, 0.1-0.25, 0.25-0.5, 0.5-1.0, and 1.0-2.0 mm. The plow pan of investigated fields appeared at a range from 5 to 30 cm depth, showing minimum value in sandy-textured management group and maximum value in ordinary management group. The thickness of plow pan were distributed from 5 to 17 cm, showing both minimum and maximum values in sandy-textured management group. Averagely, the plow appearing depth were deeper in ordinary management group than in sandy-textured management group, whereas the reverse in the thickness of plow pan. The particle size distribution fractal dimension ($D_m$) had higher value with finer textures, with higher fractality in coarser texture. Saturated hydraulic conductivities, $K_s$, of plow pan soils distributed from 0.5 to 1420 mm $day^{-1}$, having the highest value in sandy skeletal soils. The $K_s$ decreased with decreasing clay content and $D_m$, showing power function relationships. The coefficient of determination, $R^2$, of the fitted power functions were higher in $D_m$ as x-axis than in clay content. This means that $D_m$ could give us more effective estimation than clay content. Especially, sandy-textured paddy soils had higher $R^2$, compared to ordinary paddy soils. $K_s$ of relatively coarse-textured soils with less than 18%of clay content, therefore, was more dependent on particle size distribution than that of relatively fine-textured soils. From these results, it could be concluded that the fractal scaling gives us a unique quantity describing particle size distribution and then can be applied to estimate saturated hydraulic conductivity, especially more effective in coarse-textured soils.