• Proceedings of the Membrane Society of Korea Conference
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• 2003.05a
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• pp.114-117
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• 2003

• Proceedings of the Korean Society of Environment and Ecology Conference
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• autumn
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• pp.46-50
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• 2004

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2001.05a
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• pp.335-338
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• 2001

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.5
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• pp.72-78
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• 2000

• Proceedings of the Korean Society of Life Science Conference
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• 2000.09a
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• pp.58-58
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• 2000

• Korean Journal of Agricultural Science
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• v.1 no.1
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• pp.27-33
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• 1974

This experiment was carried out to determine the adequate amount of nitrogen for densely and lately seeded soybean, and the results obtained are as follows; 1) Various fertilization amounts of nitrogen did not effect the date of emergency, but the flowering and the maturing dates were delayed at the plots fertilized the nitrogen heavily. 2) In accordance with an increasing amount of nitrogen fertilization, the length of the stem and the internode was s gnificantly enlongated but the stem diameter was thinned down, and the latter was suggested to be the cause of lodging. 3) The 1,000 grain weight and the number of pods per hill were decreased according to the increasing the amount of nitrogen fertilization. 4) A highly significant difference in grain yield was recognized between varieties but among treatments. However, in case ot the extremly late cultivation, the grain yield of the early maturing variety (Choongbukbaek) was increased at the plot of 6 kg nitrogen.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.30-34
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• 2006

The effect of N-fertilization on yield, milling characteristics and quality of Samcheonbyeo, an early maturing rice variety, was investigated in 2002 to 2004. The study was carried out in the southern alpine area of Un-bong Sub-Station, Honam Agricultural Research Institute. Higher nitrogen levels increased number of panicle and grain per unit area, but lowed ripening rate and decreased 1,000-grain weight. Higher nitrogen levels of up to 90 kg/ha also increased head rice yield. A nitrogen level of 90 kg/ha was found optimal for increasing ripening rate and head rice yield, and rice palatability.

• Water for future
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• v.22 no.1
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• pp.117-125
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• 1989

This study deals with the performance of an acivated sludge system which is modified by the researcher to function without any additional chemical or internal recyle in removing organics, nitrogen, and phosphorus from synthetic wastewater. To improve the nutrient removal efficiency, the researcher utilized the anoxic, anaerobic, and aerobic reactor sequences with a single sludge return, whiched to nitrification/denitrification and phosphorus release/overplus accumulation. A bench scale system was operated with a view to investigating the reaction characteristics of each reactor, and to measuring the biological kinetic coefficients(Y, $K_d$, k, $K_s$) for theremoval of COD in relation to the mean cell residence time at five different MLSS concentrations, 5000, 4200, 3300, 2600, and 1900 mg/l. The results of the research showed that organic substance and nutrient were removed simultaneously by this modified activated sludge process. And the process kad 66%-99% ortho-p removal efficiency.

• Journal of the Korean Geographical Society
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• v.37 no.5
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• pp.536-550
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• 2002

This paper investigated the spatial variations of nitrogen (N) and phosphorus (P) concentrations for 38 watersheds in Pennsylvania using 7 years of hydroclimatic and water quality data. Watersheds with higher percentage of urban and agricultural land uses exhibited larger variations of nutrient concentrations than forested watersheds. N and P concentrations were strongly associated with agricultural and urban land uses, respectively. The principle component analysis identified three components - land use and topography related, hydroclimate related factors, and size. Results of partial redundancy analysis showed the joint effect of climate, land cover, and topographic variables for explaining 28.1% of the variance of nitrogen concentrations and a pure effect of land cover for explaining 41.8% of total variance of P concentrations. The geographical pattern of statewide nutrient concentrations demonstrated a strong spatial gradient; low concentration in northwestern PA and high concentrations in southeastern PA. This pattern is associated with combined effects of hydroclimate, land use, topography, and water quality at the regional scale.

• Journal of Wetlands Research
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• v.11 no.3
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• pp.9-19
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• 2009

This research addressed nonpoint source (NPS) pollution characteristics in a reclaimed rice paddy field. The paddy has an area of around 2,998 ha and is divided as two sub-watersheds, whose areas are 1,181 ha and 1,817 ha, respectively. Monitoring of hydrologic runoff and NPS pollution was undertaken during three-month period from June to August, 2008. Totally, three sampling trips were made when rainfall depth were 66.0 mm, 23.5 mm, and 23.0 mm, respectively. Generally pollution load increased with the heavier cultivation activity in Korea. Exported pollutants from the rice paddy, including TSS, TN and TP, have same levels as forest discharge. Organic nitrogen is main pattern but it mainly exists in the forms of dissolved organic nitrogen (DON). For phosphorus, dissolved inorganic phosphorus (DIP) takes the main part although part of them is associated with fine particles. This is different compared with other watersheds, where particles-associated phosphorus is the main form.