• Title/Summary/Keyword: Soil Property

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Development and Application of the SWAT HRU Mapping Module for Estimation of Groundwater Pollutant Loads for Each HRU in the SWAT Model (SWAT HRU별 지하수 오염부하량 산정을 위한 SWAT HRU Mapping Module 개발 및 적용)

  • Ryu, Ji Chul;Mun, Yuri;Moon, Jongpil;Kim, Ik Jae;Ok, Yong Sik;Jang, Won Seok;Kang, Hyunwoo;Lim, Kyoung Jae
    • Journal of Environmental Policy
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    • v.10 no.1
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    • pp.49-70
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    • 2011
  • The numerous efforts have been made in understanding generation and transportation mechanism of nonpoint source pollutants from agricultural areas. Also, the water quality degradation has been exacerbated over the years in many parts of Korea as well as other countries. Nonpoint source pollutants are transported into waterbodies with direct runoff and baseflow. It has been generally thought that groundwater quality is not that severe compared with surface water quality. However its impacts on groundwater in the vicinity of stream quality is not negligible in agricultural areas. The SWAT model has been widely used in hydrology and water quality studies worldwide because of its flexibilities and accuracies. The spatial property of each HRU, which is the basic computational element, is not presented. Thus, the SWAT HRU mapping module was developed in this study and was applied to the study watershed to evaluate recharge rate and $NO_3-N$ loads in groundwater. The $NO_3-N$ loads in groundwater on agricultural fields were higher than on forests because of commercial fertilizers and manure applied in agricultural fields. The $NO_3-N$ loads were different among various crops because of differences in crop nutrient uptake, amount of fertilizer applied, soil properties in the field. As shown in this study, the SWAT HRU mapping module can be efficiently used to evaluate the pollutant contribution via baseflow in agricultural watershed.

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A Study of Removal Property of Harmful Algal Blooms by Hwangto and Oriental Mineral Medicines (황토와 광물성 한약재의 적조구제 특성에 관한 연구)

  • Kim, Pil-Geun;Sung, Kyu-Youl;Jang, Young-Nam;Park, Maeng-Eon
    • Journal of the Mineralogical Society of Korea
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    • v.19 no.4 s.50
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    • pp.277-289
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    • 2006
  • This study was carried out to find a new material having high removal efficiency for the harmful red tide. C. polykrikoides grow very fast and accumulate into dense and visible patches near the surface of the seawater ('Water bloom'). Some mineral medicines and Hwangto (reddish soil consist of clay minerals and Fe-oxides) were used in this study to remove C. polykrikoides. The pre-determined sprinkling ratio of mineral vs. seawater which contains approximately 5,000 cells/mL of C. polykrikoides was 10 g/L. In order to quantify the removal efficiency, the density of living cells was measured by counting with the Intervals of 0, 10, 30, and 60 minutes after sprinkling. Five Hwangtos feom different localities were examined in this study. It is found that a material with a high concentration of Fe and Al was the most effective to remove C. polykrikoides. After the sprinkling of the Hwangto showing the best removal efficiency in the test, 99% of total algaes were found to be eliminated within 60 minutes. Jeokeokji showed the highest removal efficiency among clay mineral medicines(92% removal efficiency after 60 minutes), and the rests in decreasing order are as follows: Gamto (91%) > Baekseokji (89%) > Hydromica (81%). In addition, Fe-oxide mineral medicine similarly looking as fine-grained earthy Daejaseok showed 100% removal efficiencyafter 30 minutes, and Wooyoeryang, 95% after 60 minutes. It is noted that even little addition (1 g/L) of Daejaseok, 10% of Hwangto concentration into seawater showed the removal efficiency of 100% after 60 minutes. From the results, it could be concluded that the fine-grained earthy Daejaseok was the most effective natural mineral medicine to remove the C. polykrikoides from seawater. Under the microscope the removal mechanism was found to be activated in the following order: adsorption, swelling of chain colony, chain colony crisis and algaecide.

Study on Dry Matter Yields and Persistence of Forage Plants Using Cattle Feedlot Manure in Fallow Paddy Land Located in the Mid-mountain Area (퇴구비를 시용한 중산간지 휴경답에서 초종별 영속성 및 건물생산성에 관한 연구)

  • Yoon, Sei-Hyung;Ji, Hee-Chung;Lee, Sang-Hoon;Choi, Eun-Min;Jeong, Min-Woong
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.30 no.4
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    • pp.317-324
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    • 2010
  • Recently, fallow paddy land located in the mid-mountain area (FPL) due to a decrease in rice consumption has increased in some regions of our country. So, grasses and forage crops available for years in once sowing should be introduced in FPL. This study was conducted to develop the technique for cultivation of grasses and forage crops using animal manure in FPL The field experiments were carried out from 2007 to 2009 on FPL at Kumsan, Chungbuk province in Korea. Cattle feedlot manure (CFM) was prepared by mixing feces and urine of cattle with rice straw in cattle feedlot for 6 months. The experimental plots were consisted of four treatments; tall fescue-based mixed pasture applied with chemical fertilizer (Control), mono-tall fescue pasture (MTFP), tall fescue-based mixed pasture (TFBMP), mono-Perennial ryegrass (MPR-FCM), mono-Italian ryegrass (MIR-FCM), mono-Red clover (MRC-FCM) and mono-Reed canarygrass (MRCG-FCM) applied with FCM. The field of tall fescue-based pasture had been sown with a grasses mixture containing 'Fawn' tall fescue, 'potomac' orchardgrass, 'Reveille' Perennial ryegrass, and 'kenblue' Kentuky bluegrass, 'Kenland' Red clover. Seeding rates were 16, 6, 4, 2 and $2\;ha^{-1}$, respectively. DM yields of forages and rates of grass coverage was higher in MTFP, TFBMP and MRCG-FCM as compated with control treatment. This result means that FPL has contained with favorable conditions for growing grass, because forage productivity is more than 15 tons per ha per year in fallow paddy land. In addition, the farmer can save the trouble of repeated plowing and sowing every year, due to the introduction of perennial grasses. The farmer must conduct the re-seeding and induce the improvement of management methods for the elevation of the persistence of red clover and perennial ryegrass, because both red clover and perennial ryegrass having high nutritive value and palatability was less persistent. Therefore, we suggest that FPL may be the good land for forage production utilizing FCM and FCM can be applied on FPL without any negative effects on DM production and the property of soil. FPL of Korea can be better utilized by applying FCM to the mono and/or mixed swards.

Study on Dry Matter Yields and Persistence of Forage Plants Using Swine Slurry in Fallow Paddy Land Located in the Mid-mountain Area (돈분액비를 시용한 중산간지 휴경답에서 다년생 목초의 초종별 영속성 및 건물생산성에 관한 연구)

  • Yoon, Sei Hyung;Kim, Sang Woo;Lim, Young Chul;Jung, Min Woong
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.32 no.4
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    • pp.411-418
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    • 2012
  • This study was conducted to develop the technique for cultivation of forage crops using swine slurry in fallow paddy land located in the mid-mountain area (FPL). The field experiments were carried out from 2007 to 2009 on FPL at Kumsan, Chungbuk province in Korea. Swine slurry was prepared which decayed for 6 months. The experimental plots were consisted of seven treatments; tall fescue-based mixed pasture applied with chemical fertilizer (Control), mono-tall fescue pasture (MTF), tall fescue-based mixed pasture (TFBM), mono-Perennial ryegrass (MPR), mono-Italian ryegrass (MIR), mono-Red clover (MRC and mono), Reed canarygrass (MRCG) applied with swine slurry. The field of tall fescue-based pasture had been sown with a grasses mixture containing 'Fawn' tall fescue, 'potomac' orchardgrass, 'Reveille' Perennial ryegrass, and 'kenblue' Kentuky bluegrass, 'Kenland' Red clover. Seeding rates were 16, 6, 4, 2 and 2 (kg) per ha, respectively. DM yields of forages and rates of grass coverage were higher in MTF, TFBM and MRCG as compared with control treatment. This result means that FPL has contained with favorable conditions for growing grass, because forage productivity is more than 14.5 tons per ha per year in fallow paddy land. In addition, the farmer can save the trouble of repeated plowing and sowing every year, with the introduction of perennial grasses. The farmer must conduct the re-seeding and induce the improvement of management methods for the elevation of the persistence of red clover and perennial ryegrass, because both red clover and perennial ryegrass having high nutritive value and palatability was less persistent. Therefore, we suggest that FPL may be the good land for forage production utilizing swine slurry and swine slurry can be applied on FPL without any negative effects on DM production and the property of soil. FPL of Korea can be better utilized by applying swine slurry to the mono and/or mixed swards.

Trend and Further Research of Rice Quality Evaluation (쌀의 품질평가 현황과 금후 연구방향)

  • Son, Jong-Rok;Kim, Jae-Hyun;Lee, Jung-Il;Youn, Young-Hwan;Kim, Jae-Kyu;Hwang, Hung-Goo;Moon, Hun-Pal
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.47
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    • pp.33-54
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    • 2002
  • Rice quality is much dependent on the pre-and post harvest management. There are many parameters which influence rice or cooked rice qualitys such as cultivars, climate, soil, harvest time, drying, milling, storage, safety, nutritive value, taste, marketing, eating, cooking conditions, and each nations' food culture. Thus, vice evaluation might not be carried out by only some parameters. Physicochemical evaluation of rice deals with amy-lose content, gelatinizing property, and its relation with taste. The amylose content of good vice in Korea is defined at 17 to 20%. Other parameters considered are as follows; ratio of protein body-1 per total protein amount in relation to taste, and oleic/linoleic acid ratio in relation to storage safety. The rice higher Mg/K ratio is considered as high quality. The optimum value is over 1.5 to 1.6. It was reported that the contents of oligosaccharide, glutamic acid or its derivatives and its proportionalities have high corelation with the taste of rice. Major aromatic compounds in rice have been known as hexanal, acetone, pentanal, butanal, octanal, and heptanal. Recently, it was found that muco-polysaccharides are solubilized during cooking. Cooked rice surface is coated by the muco-polysaccharide. The muco-polysaccharide aye contributing to the consistency and collecting free amino acids and vitamins. Thus, these parameters might be regarded as important items for quality and taste evaluation of rice. Ingredients of rice related with the taste are not confined to the total rice grain. In the internal kernel, starch is main component but nitrogen and mineral compounds are localized at the external kernel. The ingredients related with taste are contained in 91 to 86% part of the outside kernel. For safety that is considered an important evaluation item of rice quality, each residual tolerance limit for agricultural chemicals must be adopted in our country. During drying, rice quality can decline by the reasons of high drying temperature, overdrying, and rapid drying. These result in cracked grain or decolored kernel. Intrinsic enzymes react partially during the rice storage. Because of these enzymes, starch, lipid, or protein can be slowly degraded, resulting in the decline of appearance quality, occurrence of aging aroma, and increased hardness of cooked rice. Milling conditions concerned with quality are paddy quality, milling method, and milling machines. To produce high quality rice, head rice must contain over three fourths of the normal rice kernels, and broken, damaged, colored, and immature kernels must be eliminated. In addition to milling equipment, color sorter and length grader must be installed for the production of such rice. Head rice was examined using the 45 brand rices circulating in Korea, Japan, America, Australia, and China. It was found that the head rice rate of brand rice in our country was approximately 57.4% and 80-86% in foreign countries. In order to develop a rice quality evaluation system, evaluation of technics must be further developed : more detailed measure of qualities, search for taste-related components, creation and grade classification of quality evaluation factors at each management stage of treatment after harvest, evaluation of rice as food material as well as for rice cooking, and method development for simple evaluation and establishment of equation for palatability. On policy concerns, the following must be conducted : development of price discrimination in conformity to rice cultivar and grade under the basis of quality evaluation method, fixation of head rice branding, and introduction of low temperature circulation.

An Analysis of Major Trail Deterioration in Urban Natural Park - A Focus on Apsan Park in Daegu Metropolitan City - (도시자연공원의 주요 등산로 훼손실태 분석 - 대구광역시 앞산공원을 대상으로 -)

  • Park, In-Hwan;Lee, Hea-Young;Cho, Kwang-Jin;Jang, Gab-Sue
    • Journal of the Korean Institute of Landscape Architecture
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    • v.38 no.3
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    • pp.33-40
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    • 2010
  • Many trails have been built and utilized in each sub-basin of Apsan Park. This study focused on the conditions and the present flora of several overused trails within three basins called Kun-Gol, Anjiroung-Gol, and Meaja-Gol in Apsan Park. There are two purposes for this study. The first is to make a plan for restoration by classifying the type of damage to these overused trails. The second is to provide preliminary data for reestablishing a more pleasant urban nature park. As a result of the survey, the average length of these trails is 9.0km and mean width is 2.0 to 2.6m. 2,108m of the sections studied(23.4% of the total) had exposed root, 3,199m of the sections studied (35.5% of the total) had exposed rock, 3,270m of the sections studied(36.6% of the total) displayed damaged pathways, and 4,841m of the sections studied (53.8% of the total) had higher soil hardness. Eighty-three areas of deterioration were found and there has been extensive property destruction. As an indication of human disturbances, the Naturalization Index and Urbanization Index appeared as: Kun-Gol, 7.0%, 5.5%; Anjiroung-Gol, 8.3%, 4.5%; Meaja-Gol 8.6%, 6.2%; in total, 7.8%, 8.3%. As a method of checking the level and extent of the damage process, an impact rating classification was used at each point on the trails. Kun-Gol had the highest rating and Anjiroung-Gol had the lowest rating in impact rating classification. With the impact rating classification, it was found that each trail would continue to worsen, meaning that roots and rocks are more likely to be further exposed and the trail width will continue to widen through overuse. An actual plan for reparations and restoration of the trails is needed through further study.

A Study on Ecological Characteristics and Changes of Vegetation in Hamyangsangrim (함양상림 식생의 생태적 특성 변화 연구)

  • Kim, Dong-Wook;Lee, Seung-Joo;Lee, Soo-Dong;Kim, Ji-Seok;Han, Bong-Ho
    • Korean Journal of Environment and Ecology
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    • v.26 no.4
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    • pp.537-549
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    • 2012
  • The purpose of this study was to provide data for the basic research to found the effective conservation and management plan for the Hamyangsangrim designated as Natural Monument No. 154 and surround areas by analyzing the ecological characteristics such as landuse and actual vegetation, plant community structure, soil chemical property and also to identify the tendency of the ecosystem changes through comparison with past studies. According to analysis the results, the landuse and actual vegetation of survey site was classified as 8 types which were forest, artificial greenspace, plaza and open-space, bare ground and the pavement, water bodies, facilities, agricultural land and etc.. It was also categorized as 38 types according to detailed characteristic. 15 kinds of forest vegetation community types comprising silva were classified among them. The changes of actual vegetation showed little variation that the Quercus serrata-Carpinus tschonoskii forest was the most widely distributed in 2003(forest area ratio is 48.3%) and 2010(forest area ratio is 48.1%), whereas, the Quercus serrata forest declined a more dramatic from 11.6% to 23.2%. The Quercus serrata-Carpinus tschonoskii forest increased sharply(11.6% ${\rightarrow}$ 23.2%) and also the Quercus serrata-Zelkova serrata forest increased steadily(2.2% ${\rightarrow}$ 7.9%). The agricultural land around forest was transformed into artificial green zone. Moreover, water bodies, bare ground and the pavement of areas have increased. In addition, the urbanized area has decreased because the damaged areas inside forest have been restored to the woodlands. According to the result of typical 6 types vegetation communities change, the middle layer trees grew up to the canopy layer trees and was formed the canopy layer structure. The middle layer trees expanded their forces widely. Also new species appeared. And the shrub individuals also more dramatically increased due to the growth of shrubs. The force of Quercus serrata declined as well. However the force of Carpinus tschonoskii and Zelkova serrata expanded and increased in the forest. It must be the result of the ecological vegetation succession and environmentally soundly health recovery by influence of the projects of forest surrounding environment improvement and limitation of access to forest have managed and maintained since 2003. Those sorts of changes seems to be going to develop continuously. In the future Carpinus tschonoskii and Zelkova serrata will not be only codominant in the canopy layer but also Carpinus Tschonoskii, Zelkova serrata, Meliosma myriantha, Sapium japonicum. Styrax obassia and Acer pseudo-sieboldianum will be codominant in the middle layer. As a result, the forest's codominance species are going to be changed such like that.

Comparison of Water Potential Parameters in Aster scaber and Synurus deltoides Leaves Obtained from P-V Curves (P-V 곡선법에 의한 참취와 수리취의 수분포텐셜 비교)

  • Lee, Kyeong-Cheol;Jeon, Seong-Ryeol;Han, Sang-Sup
    • Korean Journal of Plant Resources
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    • v.24 no.4
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    • pp.413-418
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    • 2011
  • This study was carried out to establish a proper cultivation site and diagnose the drought-tolerance of Aster scaber and Synurus deltoides leaves by using Pressure-volume curves. In order to measure pressure-volume (P-V) curves, Aster scaber and Synurus deltoides were cut off above ground part and the tip of the cutting were placed in water, which was covered with a plastic bag. Samples were kept overnight (about 12 hours) in darkness at room temperature (20~25$^{\circ}C$) to achieve maximal turgor (full saturation). The pressure in the chamber was gradually increased from 0.3MPa to 1.8MPa by nitrogen gas. After measured, leaf samples were dried at 80$^{\circ}C$ for 48 hours and dry weight of each samples were determined. The result of the original bulk osmotic potential at maximum turgor ${\Psi}^{sat}_o$ sat was lower -0.8 MPa in Aster scaber leaves than -0.7 MPa Synurus deltoides leaves. Also the osmotic potential at incipient plasmolysis ${\Psi}^{tlp}_o$ in Aster scaber leave was -0.9 MPa. In contrast, the value of maximum bulk modulus of elasticity $E_{max}$ of Aster scaber leaves were approximately two folds higher than that of Synurus deltoides leaves. The values of the relative water content at incipient plasmolysis $RWC^{tlp}$ are all above 90% showing that the function of osmoregulation is somewhat better, and Vo/DW, Vt/DW, Ns/DW of Synurus deltoides leaves were approximately 1~2 times higher than that of Aster scaber leaves. Thus, responses to water relations of Aster scaber and Synurus deltoides such as ${\Psi}^{sat}_o$, ${\Psi}^{tlp}_o$, $E_{max}$, ${\Psi}_{P,max}$, $RWC^{tl}$ were shown that the Aster scaber leaves was slightly higher drought-tolerance than Synurus deltoides leaves. However, in both of Aster scaber and Synurus deltoides, occurring incipient plasmolysis at the high water content, have a relatively lower drought-tolerance property indicating that growth of these plants are cultivated appropriate in high moisture soil sites.

A study on the field tests and development of quantitative two-dimensional numerical analysis method for evaluation of effects of umbrella arch method (UAM 효과 평가를 위한 현장실험 및 정량적 2차원 수치해석기법 개발에 관한 연구)

  • Kim, Dae-Young;Lee, Hong-Sung;Chun, Byung-Sik;Jung, Jong-Ju
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.11 no.1
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    • pp.57-70
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    • 2009
  • Considerable advance has been made on research on effect of steel pipe Umbrella Arch Method (UAM) and mechanical reinforcement mechanism through numerical analyses and experiments. Due to long analysis time of three-dimensional analysis and its complexity, un-quantitative two-dimensional analysis is dominantly used in the design and application, where equivalent material properties of UAM reinforced area and ground are used, For this reason, development of reasonable, theoretical, quantitative and easy to use design and analysis method is required. In this study, both field UAM tests and laboratory tests were performed in the residual soil to highly weathered rock; field tests to observe the range of reinforcement, and laboratory tests to investigate the change of material properties between prior to and after UAM reinforcement. It has been observed that the increase in material property of neighboring ground is negligible, and that only stiffness of steel pipe and cement column formed inside the steel pipe and the gap between steel pipe and borehole contributes to ground reinforcement. Based on these results and concept of Convergence Confinement Method (CCM), two dimensional axisymmetric analyses have been performed to obtain the longitudinal displacement profile (LDP) corresponding to arching effect of tunnel face, UAM effect and effect of supports. In addition, modified load distribution method in two dimensional plane-strain analysis has been suggested, in which effect of UAM is transformed to internal pressure and modified load distribution ratios are suggested. Comparison between the modified method and conventional method shows that larger displacement occur in the conventional method than that in the modified method although it may be different depending on ground condition, depth and size of tunnel, types of steel pipe and initial stress state. Consequently, it can be concluded that the effect of UAM as a beam in a longitudinal direction is not considered properly in the conventional method.