• Geomechanics and Engineering
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• v.17 no.5
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• pp.475-483
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• 2019

Vegetation cover plays a vital role in stabilizing the soil structure, thereby contributing to surface erosion control. Surface vegetation acts as a shelterbelt that controls the flow velocity and reduces the kinetic energy of the water near the soil surface, whereas vegetation roots reinforce the soil via the formation of root-particle interactions that reduce particle detachment. In this study, two vegetation-testing trials were conducted. The first trial was held on cool-season turfgrasses seeded in a biopolymer-treated site soil in an open greenhouse. At the end of the test, the most suitable grass type was suggested for the second vegetation test, which was conducted in an environmental control chamber. In the second test, biopolymers, namely, starch and xanthan gum hydrogels (pure starch, pure xanthan gum, and xanthan gum-starch mixtures), were tested as soil conditioners for improving the water-holding capacity and vegetation growth in sandy soils. The results support the possibility that biopolymer treatments may enhance the survival rate of vegetation under severe drought environments, which could be applicable for soil stabilization in arid and semiarid regions.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.174-174
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• 2021

지표면에서 소규모의 요철로 이루어진 미세지형 (Micro Topography)은 자연 지형의 일반적인 특징이다. 지표면에서의 흐름해석 시 이러한 미세지형에 의한 효과를 정확히 고려하기 위해서는 고해상도의 지형격자를 사용하여야 하나, 대부분의 지표유출모델은 미세지형이 존재하지 않는 저해상도의 거친 표면으로 간주함으로써 바닥 마찰 효과를 증가시켜 미세지형에 의한 영향을 대략적으로만 반영한다. 본 연구에서는 보다 정확한 강우-유출 및 유사-유출 해석을 목적으로 고해상도의 지형격자를 사용하여 미세지형을 포함한 건조 및 반건조 지대에서의 흐름을 수치적으로 모의하였다. 미세지형의 형태는 마루와 골 사이가 직선으로 이루어진 파동의 형태로 이상화 하였으며, 파동의 진폭과 파장을 조절하여 다양한 형태의 미세지형을 고려하였다. 수치모형은 흐름의 움직임에 대한 Saint-Venant 방정식과 침식 및 유사이송에 대한 Hairsine-Rose 방정식을 함께 계산하는 통합모형인 tRIBS-FEaST를 사용하였다. 수치 모의 결과에서 나타난 미세지형의 핵심 영향은 최대 유량 및 유사량 도달시간의 지연, 유사 입자 크기별 유사-유출량 증감, 그리고 하천 유출(stream flow)의 생성이었다. 또한, 미세지형의 형태에 따라 미세지형과 강우-유출 및 유사-유출 사이에 비례 혹은 반비례 관계가 성립함을 보였다. 수치 모의 결과를 종합적으로 검토하여 미세지형이 강우-유출과 유사-유출에 미치는 영향에 대해 논의하였으며, 기존 Manning 거칠기 계수를 통한 해석 방법의 적부를 판단하였다.

• Journal of Ginseng Research
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• v.14 no.2
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• pp.297-309
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• 1990

Ginseng is renowned for both its medicinal and herbal uses and successful cultivation of Panax ginseng in Asia and Panax Vtiinvtiefolilim in North America has until recently taken place in the native geographical ranges of the plants. As a consequence of the potential high capital return and anticipated increases in consumer consumption, commercial cultivation of American ginseng now occurs well outside the native range of the plant in North America. In fact, the region of greatest expansion of cultivation is in the semi-arid interior region of British Columbia, Canada. Linked with this expansion is the potential domination of the ginseng industry by agricultural corporations. In the interior of British Columbia, the native decidous forest environment of eastern North America is simulated with elevated polypropylene shade and a sllrface covering of straw mulch. The architecture of these environments is designed to permit maximillm machinery useage and to minimize labour requirements. Further, with only a four-year growth cycle, plant densities in the gardens are high. In this hot, semiarid environment, producers believe they have a competitive advantage over other regions in North America because of the low precipitation rates. This helps to minimize atmospheric humidity such that the conditions for fungal disease development are reduced. If soil moisture levels become limited, supplemental water can be provided by irrigation. The nature of the radiation and energy balance regimes of the shade and much environment promotes high soil moistilre levels. Also, the modified environment reduces soil heating. This can result in an aerial environment for the plant that is stressful and a rooting zone environment that is sub-optimal. The challenge of further refining the man modified environment for enhanced plant growth and health still remains.

• Korean Journal of Agricultural Science
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• v.47 no.1
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• pp.105-117
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• 2020

Abiotic stress is one of the most serious problems in plant productivity because it dramatically delays plant growth and development. One of the abiotic stresses, soil salinity, has an adverse effect on plant growth, particularly in areas where irrigation is necessary like semiarid Asia and Africa. Among several physiological parameters, anthocyanin accumulation is a valuable indicator of the condition of the plant, and it tends to increase under salt stress conditions because of its protective role in such an environment. Consequently, it may be important to search for well adapted genotypes for upcoming climate changes. Anthocyanins are known to have important roles in defense against biotic and abiotic stresses, providing important functions for protecting plant cells from reactive oxygen species. In this study, we investigated the anthocyanin accumulation between two Korean sorghum genotypes, Sodamchal and Nampungchal. The two genotypes were subjected to a regulated salinity condition, and the anthocyanin contents were evaluated in both. In Nampungchal, the anthocyanin content increased with 150 mM NaCl treatment during the time course of the experiment. However, the anthocyanin content of Sodamchal decreased in the same condition. The measured values of the anthocyanin content should be useful to identify the intensity of the salt tolerance in Sorghum bicolor L. Furthermore, we studied gene expression profiling of salt stress related genes with qRT-PCR. These results suggest that Nampungchal is a more tolerant genotype to salt stress compared to Sodamchal. This information should be useful for breeding salt-resistant cultivars in sorghum.

• The Plant Pathology Journal
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• v.33 no.3
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• pp.329-336
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• 2017

An experiment was conducted to evaluate the tolerance of micropropagated and mycorrhized alpinia plants to the parasite Meloidogyne arenaria. The experimental design was completely randomized with a factorial arrangement of four inoculation treatments with arbuscular mycorrhizal fungi (AMF) (Gigaspora albida, Claroideoglomus etunicatum, Acaulospora longula, and a non-inoculated control) in the presence or absence of M. arenaria with five replicates. The following characteristics were evaluated after 270 days of mycorrhization and 170 days of M. arenaria inoculation: height, number of leaves and tillers, fresh mass of aerial and subterranean parts, dry mass of aerial parts, foliar area, nutritional content, mycorrhizal colonization, AMF sporulation, and the number of galls, egg masses, and eggs. The results indicated a significant interaction between the treatments for AMF spore density, total mycorrhizal colonization, and nutrient content (Zn, Na, and N), while the remaining parameters were influenced by either AMF or nematodes. Plants inoculated with A. longula or C. etunicatum exhibited greater growth than the control. Lower N content was observed in plants inoculated with AMF, while Zn and Na were found in larger quantities in plants inoculated with C. etunicatum. Fewer galls were observed on mycorrhized plants, and egg mass production and the number of eggs were lower in plants inoculated with G. albida. Plants inoculated with A. longula showed a higher percentage of total mycorrhizal colonization in the presence of the nematode. Therefore, the association of micropropagated alpinia plants and A. longula enhanced tolerance to parasitism by M. arenaria.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.79-84
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• 2003

The main objective of this study was to investigate the chemical characteristics of post-harvest biomass burning aerosols from field burning of barley straw in late spring and rice straw in late fall in rural area in Korea. 12-hr integrated intensive sampling of $PM_{10}$ and $PM_{2.5}$ biomass burning aerosols had been conducted continuously at Gwangju, Korea 4-15 June 2001 and 8 October-14 November 2002. The fine and coarse particles of biomass burning aerosols were collected for mass, ionic, elemental, and carbonaceous species analysis. Average fine and coarse mass concentrations of biomass burning aerosols were measured to be 129.6, 24.2 ${{\mu}gm}^{-3}$ in June 2001 and 47.1, 33.2 ${{\mu}gm}^{-3}$ in October to November 2002, respectively. Exceptionally high level of $PM_{2.5}$ concentration up to 157.8 ${{\mu}gm}^{-3}$ well above 24-hour standard was observed during the biomass burning event days under stagnant atmosphere condition. During biomass burning periods dominant ionic species were $Cl^{-}$, ${NO_3}^{-}$, ${SO_4}^{2-}$, and ${NH_4}^{+}$ in fine and coarse mode. In the fine mode $Cl^{-}$ and ${KCl}^{+}$ were unusually rich due to the high content of the semiarid vegetation. High OC values and OC/EC ratios were also measured during the biomass burning periods. Increased amount of fine aerosols with high enrichment, which were originated from biomass burning of post-harvest agricultural waste, resulted in extremely severe particulate air pollution and visibility degradation in the region. Particulate matters from open field burning of agricultural wastes cause great adverse impact on local air quality and regional climate.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.1
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• pp.35-43
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• 2020

Objective: The aim of this research was to evaluate the effect of different concentrate levels in diets based on cactus Opuntia Stricta (Haw.) Haw cladodes on the performance of lactating Girolando cows. Methods: The experiment involved 10 Girolando multiparous dairy cows at 512.6 kg of body weight (BW) and producing 13.2 kg milk/d, allocated into two 5×5 Latin squares. The experimental treatments consisted of control diet composed by cactus Nopalea cochenillifera. Salm-Dyck. cladodes (Nopalea), forage sorghum silage and concentrate at 20% on dry matter (DM) basis, and four concentrate levels diets (20%, 24%, 28%, and 32%) plus cactus Opuntia stricta (Haw.) Haw. cladodes (Opuntia) and forage sorghum silage. Results: Regarding cows fed control diet, the nutrients intake were greater than for cows fed with cactus Opuntia and concentrate. Regarding concentrate levels, intakes of DM, organic matter (OM), crude protein (CP), non-fiber carbohydrates (NFC), and total digestible nutrients of cows increased linearly. Organic matter, CP, and NDF digestibilities were similar in between to control diet and cactus Opuntia-based diets. The digestibility of NFC increased linearly when the concentrate was inserted. The N balance was the same for control diet and cactus Opuntia-based diets, irrespective the concentrate levels. Conclusion: For cows producing 14 kg/d with 3.5% of fat, it is recommended 32% of concentrate to be included in cactus Opuntia-based diets, and the increase in concentrate level promotes a linear increase in milk yield.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.2
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• pp.189-200
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• 2016

The Republic of Tajikistan has ten former uranium mining sites. The total volume of all tailings is approximately 55 million tonnes, and the covered area is more than 200 hectares. The safe management of legacy uranium mining and tailing sites has become an issue of concern. Depending on the performance requirements and site-specific conditions (location in an arid, semiarid or humid region), a cover system for uranium tailings sites could be constructed using several material layers using both natural and man-made materials. The purpose of this study is to find a feasible cost-effective cover system design for the Degmay uranium tailings site which could provide a long period (100 years) of protection. The HELP computer code was used in the evaluation of potential Degmay cover system designs. As a result of this study, a cover system with 70 cm thick percolation layer, 30 cm thick drainage layer, geomembrane liner and 60 cm thick barrier soil layer is recommended because it minimizes cover thickness and would be the most cost-effective design.

• Water for future
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• v.29 no.4
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• pp.119-129
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• 1996

The daily soil water contents were obtained from the time domain reflectometry (TDR) method and energy balance-water budget approach with eddy correlation at the two small semiarid watersheds of Lucky Hills and Kendall during the summer rainy period. There was a comparison of daily soil water content measured and estimated from these two different approaches. The comparison is valuable to evaluate the accuracy of current soil water content measuring system using TDR and energy balance-water budget approach using eddy correlation method at small watersheed scale. The degree of similarity between the regressions of these two methods of measuring soil water content was explained by determining the correlations between these methods. Simple linear regression analyses showed that soil water content measured from TDR method was responsible for 58% and 63% of the variations estimated from energy balance-water budget approach with eddy correlation at Lucky Hills and Kendall, respectively. The scatter plots and the regression analyses revealed that two different approaches for soil water content measurement at small watershed scale have no significant difference.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.194-194
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• 2016

Gansu, located in the northwestern region, is a typical agricultural province of arid, semiarid in China. The shortage of water resources is the biggest obstacle of Gansu Province's development, and the dry farming water-saving is the eternal theme of Gansu agricultural sustainable development. In recent years, intensify reform in Gansu, has walked out a successful way in the agricultural water-saving. Using the integrated river basin governance as opportunity, the total water-using quantity was regarded as rigidity to retrain, distributed to counties (districts), irrigated areas, towns, associations, groups step by step. Agricultural water price was substantially increased, with the surface water price from about $0.1RMB/m^3$ to more than $0.2 RMB/m^3$, and the ground water from zero to more than $0.1RMB/m^3$. Simultaneously, the difference water prices and over-quota water progression price markup were carried out. The transaction of water rights was encouraged to impel the peasant to establish the consciousness of saving-water. The regulatory documents were formulated to standardize the scope, condition, mode, program etc. of agriculture water-rights transaction, to guarantees the transaction of water rights is carries out in order. The pattern of farming was optimized and adjusted, reducing the high water-consumption crop, increasing economic crops with high benefit and low water-consumption, developing industrialized agricultures such as green house. The relative engineering and measuring facility were comprehensively improved, with the anti-seepage of canal system and the enforcement of dynamo-electric well, developing high-efficient water-saving irrigation and overall metering facilities. The water fine-grained management has realized, and obvious water-saving effect has obtained: water-using rate in the irrigation area by river water has brought up to 0.57 from 0.52, and by well water up to 0.84 from 0.76. Although the water price has increased, the proportion that the water rate expenditure accounted for the cost lasts decline, and the farmers' income has gone up. The peasants express, the used water is few, and it is few to till land, but the income is many, and life is better.