• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.257-268
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• 2003

Daily monitoring was conducted to elucidate the changes in turbidity and distribution of particles in the turbid water of a river-type reservoir (Paltang Reservoir) from 1999 to 2001. Water turbidity and the particle distribution of turbid water were principally affected by meteorological factors particularly rainfall patterns and hydrological factors such as inflow and outflow. The mean concentration of turbidity was constant each year, with the concentration of less than 10 NTU accounting for 85%. Seasonal characteristics were remarkable, with winter and spring having < 5 NTU, autumn 5 ${\sim}$ 10 NTU, and summer > 20 NTU. Unlike hydrological changes, maximum turbidity was observed from late July to early August and continuously increased from 1999 to 2001. In particular, the maximum turbidity of reservoirs remarkably increased toward the lower part of reservoir in 2001. Discharge and turbidity increased or decreased slowly in 1999; in contrast, turbidity rapidly increased in the early rainfall period of 2000 and 2001 but later decreased as discharge increased. In the particles of turbid water, clay ingredients were more densely distributed and more dominant in all stations. Of the total particles in turbid water, clay constituted 63.9${\sim}$66.6% and silt 33.4${\sim}$36.1% to account for a combined total of 98.9 ${\sim}$ 100%. Sand made up less than 1.1%. The turbidity of river-type reservoir was also found to be mainly affected by the biomass of plankton in a non-rainfall period. During a rainfall period, however, the quantity and relative ratio of inorganic particles depending on the soil components affected turbidity.

• Journal of architectural history
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• v.20 no.3
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• pp.7-22
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• 2011

With the accumulations of outcomes from archaeological excavations of mountain fortress of three kingdoms period, there have been studies about time-periodic territory range of mountain fortress, difference in the way(method) of construction, defence system and so on from various points of view. This is an empirical study on the construction method of the valley part of stone fortress. First of all, it is required to secure large quantity of fresh water for those who lived at mountain fortress. Especially when builders of fortress construct a fortification at the valley part of stone fortress, in advance they must sufficiently consider several options including the establishment of sustainable water resources. First, when it comes to build a fortification on a ridge[or a slope] of a mountain, you have only to consider a vertical stress. However, when it comes to build a fortification at the valley part of a mountain, You must have more sufficient preparations for the constructing process. Because there are not only a vertical stress but also a horizontal pressure simultaneously. Second, a fortification of mountain fortress built by using unit building stone is a structure of masonry construction like brick construction, and the valley part of it is where the construction of the fortification begins. Third, when it comes to build a fortification at the valley part of a mountain, it seems that they use a temporary method such as coffer dam in oder to prevent the collapse of the fortification due to heavy rain. Furthermore, in response to a horizontal pressure a fortification is built by the way of its plane make an arch, or by piling up the soil with the plate method(類似版築) and earthen wall harder method(敷葉) they increase cross-sectional area of the fortification and its cutoff capacity. In front direction they put the reservoir facility for the fear that the hydraulic pressure and earth pressure are directly transmitted to the fortification. The process of constructing the fortification at the valley part of a mountain is done in the same oder as follows; leveling of ground(整地) ${\Rightarrow}$ construction of coffer dam ${\Rightarrow}$ construction of the fortification between the both banks of the valley ${\Rightarrow}$ construction of the fortification at bottom part of spill way(餘水路) between the both banks of the valley ${\Rightarrow}$ construction of spill way(餘水路) & reservoir facility ${\Rightarrow}$ construction of the fortification at upper part of spill way between the both banks of the valley. Coffer dam facility seems to be not only the protection device on occasion of flood but also an important criterion to measure the proper height of spill way or tailrace(放水路). This study has a meaningful significance in that it empirically examines the method of reduction of the horizontal pressure which the fortification at the valley part of a mountain takes, the date the construction was done, and wether the changes in climate such as heavy rainfall influence the process of construction.

• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.321-331
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• 2006

Recently, runoff characteristics of urban area are changing because of the increase of impervious area by rapidly increasing of population and industrialization, urbanization. It needs to extract the accurate topologic and hydrologic parameters of watershed in order to manage water resource efficiently. Thus, this study developed more precise input data and more improved parameter estimating procedures using GIS(Geographic Information System) and GA(Genetic Algorithm). For these purposes, XP-SWMM (EXPert-Storm Water Management Model) was used to simulate the urban runoff. The model was applied to An-Yang stream basin that is a typical Korean urban stream basin with several tributaries. The rules for parameter estimation were composed and applied based on quantity parameters that are investigated through the sensitivity analysis. GA algorithm is composed of these rules and facts. The conditions of urban flows are simulated using the rainfall-runoff data of the study area. The data of area, slope, width of each subcatchment and length, slope of each stream reach were acquired from topographic maps, and imperviousness rate, land use types, infiltration capacities of each subcatchment from land use maps, soil maps using GIS. Also we gave the management scheme of urbanization runoff using XP-SWMM. The parameters are estimated by GA from sensitivity analysis which is performed to analyze the runoff parameters.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.356-356
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• 2017

A field experiment was performed to evaluate the effects of tillage systems and fertilizer management on yield and nutrient uptake in Soybean. The plant height, fresh weight and dry weight of conventional tillage were much higher those observed for no-tillage. Significant differences in plant height were observed under tillage practices combined with fertilizer treatment. However, the greatest plant height (128.47 cm) was observed in conventional tillage with chemical fertilizer, and the lowest (45.4 cm) was observed in the no-tillage with green manure treatment. The highest fresh weight (172.4 g) and dry weight (44.1 g) were observed from the no-tillage chemical treatment in the late flowering stage of soybean. The plant concentration of nitrate was higher (2.29%) in no-tillage with green manure than it was with chemical fertilization. However, nitrogen increased steadily in all treatments, and the highest quantity of total nitrogen (476.7 Kg/ha) was observed in no-tillage with green manure. The N content in the soil decreased gradually just after the vegetative stage. Tillage practices and additional fertilizer application had an adverse effect on the uptake of N, P and K in soybean seeds. The nitrogen concentration in seeds was found to be increased in the no-tillage with green manure treatment. The uptake of more nitrogen induced a better yield. Thus, the no-tillage with green manure treatment had the greatest yield, although no significant difference was observed among foliar-applications and additional fertilization. Additionally, the phosphorus and potassium concentrations in seeds remained the same between the conventional tillage and no-tillage treatments. The results obtained in this study indicate that no-tillage strategies with fertilizers may influence the growth characteristics and mineral uptake in soybean.

• Journal of Korean Society of Forest Science
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• v.55 no.1
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• pp.22-29
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• 1982

Two ectomycorrhizal fungi, Pisolithus tinctorius and Thelephora terrestris, were introduced form U.S.A. and inoculated to five pine species in Korea to evaluate the reported growth stimulation of host plants after inoculation. These fungi were grown as mycelial inoculum in large quantity and ioculated to the fumigated nursery soil just before seed sowing. At the end of the first growing season. Pisolithus stimulated the height growth of Pinus densiflora. P. thunbergii. P. rigida, and P. rigida x teada by55, 36, 69, and 37%, respectively, compared with control seedlings with no fumigation and no inoculation. When the growth stimulation was expressed with dry weight, Pisolithus increased dry weight of P. densiflora and P. rigida x taeda by 143% and 128%, respectively, over control seedling. Thelephora failed to stimulate growth of inoculated plants. Pinus koraiensis did not respond to the inoculation during the first growing season. It is concluded that artificial inoculation of nursery pine trees with selected mycorrhizal fungi should be seriously considered to improve the quality of planting stocks and to stimulate early plant growth. The potential for use of Pisolithus in reforestation on adverse sited is also discussed.

• Applied Biological Chemistry
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• v.14 no.3
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• pp.183-189
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• 1971

The studies reported herein were conducted to inquire the effect of fused siliceous materials which mixed with sand and quartz added calcium fertilzer on rice grown on low available silica content soil. The applied nitrogen level were examined for the two plots, nitrogen 10kg and 20kg per 10 a., and the siliceous materials(Wollastonite, Fused sand and Fused quartz) were applied as levels to 100kg, 300kg and 500kg per 10a. in the pots. The results are summerized as follows; 1. The available silica content solved in N/2 HCl solution of fused sand was more than of fused quartz but the silica solubility in 2% citric acid of fused quartz were higher than other. 2. The absorbed silica content by plant grown on the fused quartz plot was the highest among other siliceous materials and of fused sand and natural wollastonite were at almost equal. The ratio of absorbed silica of natural wollastonite was highest among them and in fused materials, the quartz was higher than sand. 3. The productivity of rice was increased by percentage of filled grain, weights of 1000 grains, and number of spikelets on account of the large quantity of the silica absorbed by plant Especially fused quartz showed the highest productive effect among siliceous materials and natural wollastonite and fused sand were similar effect. 4. From the above results. the fused quartz was selected as expelled siliceous fertilizer on rice plant among them and the fused sand was equal effect to natural wollastonite.

• Journal of Wetlands Research
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• v.16 no.4
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• pp.443-452
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• 2014

Feces contain nutrients such as nitrogen and phosphate, potassium and research of the impact on the environment from feces is very diverse. However, despite the importance of mammals to environment, studies of mammals into the terrestrial ecosystems are rare. Korean water deer (Hydropotes inermis) is an endemic species of Korea and China, and we conducted on factor of plant growth in relation to feces of Korean water deer depending on land use patterns. The analysis of growth, biomass and C/N ratio of Zea mays, amount of feces and land use patterns are strongly affecting the C/N ratio and growth of the Zea mays. The quantity of the feces also influences the growth of plants instead of the land use patterns. Furthermore, the feces of Korean water deer have a lower C/N ratio than that of other animals' feces. Being the process of composting, it is able to serve a suitable fertilizer for a crop growth. In this study, we investigated the impact of feces into the environment in the terrestrial ecosystems and we were able to provide the basic data to the resources of an efficient scheme of animal feces. Further research is needed to quantify the materials amongst the plant, soil and animal, and to understand the relationship ecosystem.

• Korean Journal of Medicinal Crop Science
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• v.22 no.2
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• pp.140-146
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• 2014

This study was carried out to investigate the difference of the content of soil chemical components and growth characteristics in six years old ginseng affected by application of decomposing plant residues in paddy-converted field. The results show that aerial parts of ginseng are no difference between press cake (PC) 200 kg/10a and control but subterranean parts of ginseng PC 200 kg/10a, especially quantity related root fresh weight and tap root diameter, are statically about 1.6 times heavier and about 1.2 times thicker than the ginseng control. Furthermore, the survival rate of PC 200 kg/10a is 67.1% rise significantly compare with the control 50.7%. But compared with the PC 200 kg/10a and the PC 400 kg/10a, ginseng root growth and survival rate of PC 400 kg/10a get worse and that increase physiological disorder occurrence rate than PC 200 kg/10a. Even though there are no significant differences between the ginseng of decomposing plant residues except press cake treatment and the ginseng of control in growth characteristics, it does tend to increase the survival rate and decrease the physiological disorder occurrence rate in most fertilizer treatment except for RSC 2 ton/10a, RSC 4 ton/10a and RH 4 kL/10a. Noted that EC is highly increased and exceeded 1.7 ds/m in RSC 2 ton/10a, RSC 4 ton/10a and RH 4kL/10a. It would be caused physiological disorder in many ways and affected ginseng growth characteristics, survival rate.

• Journal of Environmental Impact Assessment
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• v.26 no.6
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• pp.563-573
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• 2017

Coal ash is generated from coal-fired thermal power plants every year. The remaining quantity of coal ash ends up in the landfills except for the recycled portion, and the existing ash pond capacity is limited almost. Currently, the difficulties are faced in building a new ash treatment plant because of the concerns about the environmental impacts of landfills at individual plant facilities. In terms of minimizing the environmental impact, the recycling and effective uses of coal ash are recognized as urgent issues to be challenged. Accordingly, this study examines the obstacles in expanding the recycling of the coal ash in South Korea and proposes solutions based on the case study analysis. The analysis results are as follows: 1) specific recycling guidelines and standards are required to be established in accordance with the contact medium (soil, ground water, surface water and sea water) and the chemical. 2) by providing the recognition environmentally safe in recycling the coal ash, transparency in establishing the planning stages and active communication with the community through promotion and research are essentially needed. 3) practical support system is required to encourage the power plant companies to use the coal ash as beneficial use.

• Korean Journal of Environmental Agriculture
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• v.24 no.3
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• pp.295-302
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• 2005

The nitrogen (N) balance in Korea during 1985-1997 was calculated according to the surface balance method of the PARCOM guidelines and compared with Japanese N balance. The some differences were founded in the coefficients used on calculating N balance in two nations. Of the important parameters, which can make a big difference in balance, N input by organic fertilizers was not included in Korea different with Japanese, due to absence of reliable statistics and then made lower the input. Nitrogen destruction rate from livestock manure was adjusted differently with 15% in Korea but 28% in Japan. There was some difference in the conversion factors of livestock number into manure N quantity in two nations, but the gap was ignoble scale except beef cattle. Our manure N production rate of beef cattle might be evaluated to be so lower than Japanese. Biological N fixation by pulses was very higher in Korea than in Japan but scarcely affect the increase of total N input, due to small cultivation area. In contrast, N fixation rate by free-living organisms in Korean and Japanese wet paddies showed the big difference with 7.6 and $37.0kg\;ha^{-1}\;yr^{-1}$, respectively, and therefore $29.4kg\;ha^{-1}\;yr^{-1}$ of nitrogen was estimated to be more inputted in Japan. Although there are many points to be more specified and improved, still, Korean N balance was very high with $250-257kg\;ha^{-1}$ in the mid of 1990s, which was the second highest level in OECD countries and furthermore increased continuously during the investigation. In contrast in Japan, which has similar fanning system with Korea, N balance was lower with $130-158kg\;ha^{-1}$ and has decreased continuously since 1993. This high N balance was mainly due to a high usage of chemical fertilizers in our intensive fanning system and the fast increment of livestock feeding. Therefore, the more active action to decrease chemical fertilizer utilization and reduce livestock feeding density is required in the government and farmer sides.