• Title, Summary, Keyword: Nitrogen management

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Effect of Long Term Fertilization on Soil Carbon and Nitrogen Pools in Paddy Soil

  • Lee, Chang Hoon;Jung, Ki Youl;Kang, Seong Soo;Kim, Myung Sook;Kim, Yoo Hak;Kim, Pil Joo
    • Korean Journal of Soil Science and Fertilizer
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    • v.46 no.3
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    • pp.216-222
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    • 2013
  • Fertilizer management has the potential to promote the storage of carbon and nitrogen in agricultural soils and thus may contribute to crop sustainability and mitigation of global warming. In this study, the effects of fertilizer practices [no fertilizer (Control), chemical fertilizer (NPK), Compost, and chemical fertilizer plus compost] on soil total carbon (TC) and total nitrogen (TN) contents in inner soil profiles of paddy soil at 0-60 cm depth were examined by using long-term field experimental site at $42^{nd}$ years after installation. TC and TN concentrations of the treatments which included N input (NPK, Compost, NPK+Compost) in plow layer (0-15 cm) ranged from 19.0 to 26.4 g $kg^{-1}$ and 2.15 to 2.53 g $kg^{-1}$, respectively. Compared with control treatment, SOC (soil organic C) and TN concentrations were increased by 24.1 and 31.0%, 57.6 and 49.7%, and 72.2 and 54.5% for NPK, Compost, and NPK+Compost, respectively. However, long term fertilization significantly influenced TC concentration and pools to 30 cm depth. TC and TN pools for NPK, Compost, NPK+Compost in 0-30 cm depth ranged from 44.8 to 56.8 Mg $ha^{-1}$ and 5.78 to 6.49 Mg $ha^{-1}$, respectively. TC and TN pools were greater by 10.5 and 21.4%, 30.3 and 29.6%, and 39.9 and 36.3% in N input treatments (NPK, Compost, NPK+Compost) than in control treatment. These resulted from the formation and stability of aggregate in paddy soil with continuous mono rice cultivation. Therefore, fertilization practice could contribute to the storage of C and N in paddy soil, especially, organic amendments with chemical fertilizers may be alternative practices to sequester carbon and nitrogen in agricultural soil.

On-the-go Nitrogen Sensing and Fertilizer Control for Site-specific Crop Management

  • Kim, Y.;Reid, J.F.;Han, S.
    • Agricultural and Biosystems Engineering
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    • v.7 no.1
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    • pp.18-26
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    • 2006
  • In-field site-specific nitrogen (N) management increases crop yield, reduces N application to minimize the risk of nitrate contamination of ground water, and thus reduces farming cost. Real-time N sensing and fertilization is required for efficient N management. An 'on-the-go' site-specific N management system was developed and evaluated for the supplemental N application to com (Zea mays L.). This real-time N sensing and fertilization system monitored and assessed N fertilization needs using a vision-based spectral sensor and controlled the appropriate variable N rate according to N deficiency level estimated from spectral signature of crop canopies. Sensor inputs included ambient illumination, camera parameters, and image histogram of three spectral regions (red, green, and near-infrared). The real-time sensor-based supplemental N treatment improved crop N status and increased yield over most plots. The largest yield increase was achieved in plots with low initial N treatment combined with supplemental variable-rate application. Yield data for plots where N was applied the latest in the season resulted in a reduced impact on supplemental N. For plots with no supplemental N application, yield increased gradually with initial N treatment, but any N application more than 101 kg/ha had minimal impact on yield.

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Recovery and Recycling of Nitrogen and Phosphorus as Struvite from Livestock Excreta (가축분뇨로부터 struvite 결정화에 의한 질소 (N), 인 (P) 회수 및 자원화 방안 고찰)

  • Ryu, Hong-Duck;Ahn, Ki Hong;Chung, Eu Gene;Kim, Yongseok;Rhew, Doughee
    • Journal of Environmental Science International
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    • v.26 no.1
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    • pp.119-131
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    • 2017
  • This study evaluated the feasibility of recovering and recycling nitrogen (N) and phosphorus (P) from livestock excreta as struvite ($MgNH_4PO_4{\cdot}6H_2O$) in South Korea. Our experimental results showed that struvite precipitation was a very effective way to recover N and P from livestock excreta. Moreover, our study demonstrated that struvite precipitates from livestock excreta (SPL) contain higher concentrations of N, P, and magnesium (Mg) as compared to compost and liquid manure from livestock excreta. In addition, although SPL contain high concentrations of copper (Cu) and zinc (Zn), they meet the fertilizer criteria for concentrations of heavy metals. In South Korea, SPL cannot currently be used as a fertilizer due to legal constraints. Legal permission for SPL use would offer greater choice in livestock excreta management. In conclusion, recovery and recycling of N and P from livestock excreta as struvite can be an effective tool for managing nutrients in livestock excreta.

The Lubrication Effect of Liquid Nitrogen in Cryogenic Machining [I]- Part 1: Cutting Force Component with Physical Evidences - (Liquid Nitrogend의 감찰효과 -물리적 현상에 의한 절삭력-)

  • Jun Seong Chan;Jeong Woo Cheol
    • Journal of the Korea Safety Management and Science
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    • v.4 no.2
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    • pp.209-221
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    • 2002
  • Machinability improvement by the use of liquid nitrogen in cryogenic machining has been reported in various studies. This has been mostly attributed to the cooling effect of liquid nitrogen. However, No study has been found in discussion on whether liquid nitrogen possesses lubrication effect in cryogenic cutting. In machining tests, cryogenic machining reduced the force component in the feed direction, indicating that the chip slides on the tool rake face with lower friction. This study also found that the effectiveness of LN2 lubrication depends on the approach how LN2 is applied regarding cutting forces related.

The Flame Image Observation for Monitoring Management of Pulverized Coals Firings and its Feasibility Test to Boilers for Thermal Power Plant (미분탄 연소의 감시 관리를 위한 화염영상 감시 및 발전용 보일러 적용시험)

  • Baek, Woon-Bo
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.1
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    • pp.92-98
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    • 2008
  • The flame image observation and analysis has been investigated for combustion monitoring and management of the pulverized coal firing for thermal power plant, especially for lower nitrogen oxide generation and safer operation. We aimed at obtaining the relationship between burner flame image information and emissions of nitrogen oxide and unburned carbon in furnace utilizing the flame image processing methods, by which we quantitatively determine the conditions of combustion on the individual homers. Its feasibility test was undertaken with Samchonpo thermal power plant #4 unit which has 24 burners, through which the system was observed to be effective for evaluating the combustion conditions and continuous monitoring to prevent future loss of ignition.

Effects of Nitrogen Fertilizer on Growth of Indigofera pseudo-tinctoria in Kyongseodong Waste Landfill, Incheon

  • Kim, Kee-Dae;Lee, Sang-Mo;Lee, Eun-Ju
    • The Korean Journal of Ecology
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    • v.26 no.2
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    • pp.71-74
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    • 2003
  • Effects of nitrogen addition on the growth of Indigofera pseudo-tinctoria (Leguminosae) in the waste landfill site was investigated. Nitrogen fertilization in the nitrogen poor soils of waste landfill may influence the growth of nitrogen fixing plants beneficially or detrimentally. When I. pseudo-tinctoria was fertilized with three different levels of nitrogen, the coverage of plants treated with 46 g N/$m^2$ and 460 g N/$m^2$ was significantly less than that of plants treated with 23 g N/$m^2$. The growth rates of plant height treated with 46 g N/$m^2$ and 460 g N/$m^2$ were significantly less than those of plants treated with 23 g N/$m^2$. The growth rates of plant diameter treated with 46 g N/$m^2$ and 460 g N/$m^2$ were significantly less than those of plants treated with 23 g N/$m^2$. Dry weights of whole plants in control sites were higher than those of all the others nitrogen treatment sites. Nodule numbers were higher in control plants than those of plants in all the other nitrogen treatment sites. It is suggested that nitrogen fertilizer addition over 23 g N/$m^2$ affect the growth of some nitrogen fixing plants, such as I. pseudo-tinctoria, negatively.

Nitrification and Denitrification of Land-based Fish Farm Wastewater using an Anaerobic-Aerobic Upflow Biological Aerated Filter (혐기-호기 상향류 필터 공정에서 양식배출수의 질산화 및 탈질 연구)

  • Park, Noh-Back;Lee, Hyun-Young;Kim, Seong-Min;Lee, Jun-Sang
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.47 no.5
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    • pp.622-629
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    • 2014
  • This study induced biological denitrification and nitrification via a biofiltration process with the view of removing nitrogen from land-based fish farm effluent. To achieve this, we operated an aquaculture nitrogen-removal system that includes a denitrification and nitrification reactor [working volume 40 L, flow rate 64.8 L, HRT (hydraulic retention time) 14.8 h, HRT considering recycling of NOx 7.4 h]. In the continuous process, the nitrification rate of ammonium nitrogen exceeded 90% at a steady state and the denitrification efficiency exceeded 80% with recycling to a pre-anoxic reactor. In addition, the pH in the final effluent was lower with a low influent water alkalinity averaging 100 mg/L (as $CaCO_3$). For effective denitrification reactions, carbon must be supplied via particulate organic matter (POM) hydrolysis because of the low C/N (carbon/nitrogen) ratio in the water.

A Study on the Formation and Reduction of NOx in 5TPD SRF Boiler (5톤/일 규모 SRF 전용 연소보일러에서의 질소산화물의 생성과 저감에 대한 연구)

  • Yoon, Young-Sik;Park, Dong-Kyu;Gu, Jae-Hoi;Park, Yeong-Su;Seo, Yong-Chil
    • Journal of Korea Society of Waste Management
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    • v.35 no.7
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    • pp.647-652
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    • 2018
  • The emission of nitrogen oxides has a great environmental impact. It leads to Los Angeles type smog, and it recently has attracted attention as a source of ultrafine dust. The main sources of nitrogen oxides are internal combustion engines and industrial boilers. These emission sources are processes that are essential for human industrial activities, so the regulation of original use is impossible. Therefore, special control methods should be applied to reduce NOx emissions into the atmosphere. In this study, we investigated how the supply of ER and urea influences the removal of nitrogen oxides from SRF combustion boilers. Experimental results show that the removal efficiency of nitrogen oxides can be up to 80% under the conditions of ER 2.0 and a urea feed of 0.5 LPM.

Modeling for Biological Nitrogen Removal in Step-Feed Process (Step-Feed 공정에서의 생물학적 질소제거 Modeling)

  • Lee, Byung-Dae
    • Journal of the Korean Applied Science and Technology
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    • v.22 no.1
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    • pp.62-70
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    • 2005
  • Step-feed process for biological nitrogen removal were analyzed numerically for the each unit and final total nitrogen(TN) effluent by water quality management(WQM) model and the results were compared data from these wastewater treatment plants. No bugs and logic error were occurred during simulation work. All of the simulation results tried to two times were obtained and both results were almost same as this model has become good reappearance. It was concluded that most of nitrogen removal occurred in the first oxic tank. Thus the controlling of the first anoxic tank may be more important in term of nitrogen removal. Also each unit of simulation result was kept good relationship with that of measured data. Accordingly this WQM model has good reliance. Finally, WQM model can predict final TN effluent within ${\pm}6.0mg/{\ell}$.

Analysis of Water Quality caused by Improvement of Sewage Treatment Plant in Masan Bay (하수처리장 개선이 마산만 수질에 미치는 영향분석)

  • Oh Hyun-Taik;Goo Jun-Ho;Park Sung-Eun;Choi Yun-Sun;Jung Rae-Hong;Choi Woo-Jeung;Lee Won-Chan;Park Jong-Soo
    • Journal of Environmental Science International
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    • v.14 no.8
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    • pp.777-783
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    • 2005
  • For the sustainable management of marine ecosystem in Masan Bay, we have to assess the carrying capacity and standard of target water quality. In this research, we assume that all pollutants loads are treated in Dukdong sewage treatment plant, then we simulate the physical-biological model for prediction water quality for the achievement of standard water quality. In 2001 year, for the achievement of COD 2.5 mg/L, we need to reduce COD $90\%$, nitrogen $30\%$, phosphate $90\%$ than that of the present value, According to these results, the water quality of sewage treatment plant is required to treat COD 13.5 mg/L, nitrogen 33.3 mg/L, phosphate 6,0 mg/L. If the sewage treatment plant will be expanded much larger in 2011, it will need to be treated in COD 6.6 mg/L, nitrogen 2.5 mg/L, phosphate 5 mg/L for the achievement of water quality standard in COD 2.5 mg/L.