• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.35-43
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• 1999

Biotransformation of inorganic nitrogens, which are possible contaminants of bank filtered water, in soil of near bank filtration site was investigated based on oxygen consumption and changes of chemical parameters in respirometer. Biotransformation activities of inorganic nitrogens at different conditions of pH. water content. and added initial${NH_4}_2$$SO_4$were compared. At original low pH and 20% of water content, nearly no biotransformation activity of inorganic nitrogen was observed, in addition, control and NH$_4$-added sets did not show any significant differences of oxygen consumption. Among tested conditions, the highest activity was observed at 25% water content and pH 8. Nearly 98% nitrification activity was observed at sets amended with 400 mg $NH_4$-N/kg soil as${NH_4}_2$$SO_4$in the condition of pH 8 and 20~23% water content. However, considerable activity of subsequent denitrification was not observed.

• Journal of Life Science
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• v.13 no.4
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• pp.473-480
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• 2003

We analyzed the patterns of mineral ions and growth responses among symbiotic nitrogen fixing legumes by external nitrogen applications under salt gradients. Glycine max, Phaseolus angularis and Albizzia julibrissin showed remarkable growth inhibition above 40 mM NaCl treatments, but Cassia tora did not exhibit any visible injury symptom up to 100 mM NaCl treatments. As to ionic pattern, the $Na^+$ and $Cl^-$contents in leaves of G. max, P. angularis and A. julibrissin progressively increased with higher contents of external salinity. Compared to other plants, C. tora excluded $Na^+$more efficiently and maintained rather constant ionic contents in spite of high salt levels. With a few exception, these 4 legume plants exhibited better growth by the external nitrogen supply rather than the contribution of symbiotic nitrogen fixation only under saline condition.

• Korean Journal of Organic Agriculture
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• v.21 no.1
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• pp.61-68
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• 2013

This study was conducted to evaluate overwintering of hairy vetch (Vicia villosa Roth), biomass, and inorganic N concentration in soil to verify the adaptability of eight cultivars of hairy vetch into country. Winter survival rate was higher for the hairy vetch cultivars, such as Hungvillosa or Ostsaat, than those of Minnie, Oregon common, and TTF1, which affected amount of biomass of each hairy vetch, with higher biomass observed in Hungvillosa or Ostsaat cultivar. There were no significant difference for the mineral nutrients of each hairy vetch cultivar. Inorganic N concentration in soil was increased at 10 days after mowing by application of Hungvillosa and Ostsaat cultivars that had highly produced N content from the raw materials.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.299-299
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• 2009

유기농업에서 유기자원을 이용하여 적정량의 양분을 공급하기 위해서는 먼저 유기자원의 무기화특성을 고려하여야 한다. 토성, 기온, 재배형태 등 다양한 요인을 고려하면서 무기화모델을 이용하여 유기농업에서 많이 사용되고 있는 유기질비료와 작물잔사 등을 대상으로 잠재 무기화가능 질소량(PMN, Potentially mineralizabe nitrogen)을 추정하였다. 실험은 실내에서 항온 배양하여 유기자원별 질소 무기화 양상을 분석함으로서 대상 유기자원의 PMN 및 무기화 속도를 도출하였다. 실험재료는 팜박, 피마자박, 팽화왕겨, 토마토, 수박, 감자, 마늘 등 7종을 대상으로 $20^{\circ}C,\;25^{\circ}C,\;30^{\circ}C$ 조건에서 하였으며, 최대수분보유량의 60% 수준으로 하여 사양토 및 식양토 조건에서 실험하였다. 유기자원은 토양 100g에 질소 30kg/10a 해당량을 시용하여 112일까지 항온하였다. 토성별 무기화량은 식양토 보다 사양토에서 다소 높은 경향을 보였다. 또한 항온온도가 높을수록 무기화량이 증가하였다. 유기자원별로는 피마자박에서 높았고, 팽화왕겨는 낮은 경향이었다. 유기자원이 처리된 것에서 토양 자체의 무기화량을 뺀 순무기화량은 피마자박, 토마토잔사, 감자잔사가 항온초기부터 무기화가 진행되었으며, 수박잔사, 마늘잔사는 항온 초기에 음의 값을 가지는 유기화 과정을 거친 후 항온 60일에서 80일 사이에서 무기화가 진행되었고 팽화왕겨의 경우 항온 11일까지 유기화가 계속되었다. PMN 및 무기화속도를 추정하기 위하여 반응속도식을 이용하였으며, 모델의 적합도를 높이기 위하여 이중지수모형을 이용하여 매개변수를 결정하고 무기화경향을 예측한 결과 PMN은 피마자박>마늘잔사=팜박>수박잔사=토마토잔사>감자잔사의 순이었다. 또한 유기자원의 무기화량과 C/N율과는 부의 상관관계($r^2$=0.8653)를 나타내었다. 요소의 PMN(135.6mg/kg)에 대한 유기자원별 PMN의 상대적 비율은 피마자박이 100%, 팜박과 마늘잔사가 81%, 토마토, 수박 및 감자잔사가 28~65% 수준이었다.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.4
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• pp.211-217
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• 2005

Fresh hairy vetch (HV) as a green manure equivalent to $240kg\;N\;ha^{-1}$ were incorporated into soil at corn planting in 1997 and 1998 to clarify the effects on changes of nitrogen (N) content in soil and corn plant. The influences of HV for the N of soil and plant were compared with those of ammonium nitrate (AN) in terms of mineralization and microbial biomass. During early decomposition of HV residue, the content of $NO_3-N$ in HV plot was as much as 60-70% of that in AN plot in surface soil of 0-15 cm depth. In addition, soil microbial biomass N (SMBN) by HV residue was increased up to $10-20mg\;kg^{-1}$ more than that by AN. Some mineral N from HV seemed to be released slowly until late corn growth stage judging from high content of $NO_3-N$ in both corn stem at silking stage and soil at harvest. There were no difference of N accumulations in corn plant at silking stage between HV and AN plots in both 1997 and 1998. At harvesting stage, a total of plant N accumulation in HV plot in 1997 was 8% less than that in AN plot while in 1998 it was 19% more. It was concluded that fresh HV green manure equivalent to $240kg\;N\;ha^{-1}$ was good enough to substitute the same amount with chemical N fertilizer by slow releasing of mineral N from HV residue in soil.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.4
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• pp.292-301
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• 2001

The objectives of this study were to measure the changes in soil moisture regimes and the distribution patterns of inorganic N derived from the fertigated $^{15}N$-labeled urea, and compare them with the results obtained from broadcast-applied soil under the same drip irrigation domain. In fertigated soil, a $^{15}N$-labeled urea solution of $117mg\;N\;L^{-1}$ was applied by surface drip irrigation for 4 weeks. In broadcast-applied soil, no the other hand, 4 g of $^{15}N$-labeled urea(1.87 g N) mixed thoroughly with 5 kg of soil was placed on the surface of packed soil. Soil water status was controlled by drip irrigation scheduled at soil matric potential of -50 kPa. A calibrated time-domain reflectometry probe was installed in the soil vertically 15 cm apart from a drip emitter to control drip irrigation. About 60% of urea-derived inorganic nitrogen was remained in the top zone between 0 and 10 cm depth of fertigated soil, while, most of the inorganic nitrogen (91%) was accumulated in the top zone of broadcast-applied soil. Of inorganic nitrogen derived from urea, the percentage of $NO_3{^-}$ was much higher for fertigation (99%) than for surface application (62%). The relatively lower recovery of urea-derived inorganic nitrogen of broadcast-applied urea-N (51%) than that of fertigated urea-N (89%) was attributable to enhanced $NH_3$ volatilization.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.2
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• pp.91-98
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• 2009

The long-term water-quality change of Asan Bay by the influx of polluted disposal water was predicted through a simulation with an Eco-hydrodynamic model. Eco-hydrodynamic model is composed of a multi-level hydrodynamic model to simulate the water flow and an ecosystem model to simulate water quality. The water quality simulation revealed that the COD(Chemical Oxygen Demand), dissolved inorganic nitrogen(DIN) and dissolved inorganic phosphorus(DIP) are increased at 5 stations for the subsequent 6 months after the influx of the effluent. COD, DIN and DIP showed gradual decreases in concentration during the period of one to two years after the increase of last 6 months and reached steady state for next three to ten years. Concentration levels of COD, DIN, and DIP showed the increase by the ranges of $11{\sim}67%$, $10{\sim}67%$, and $0.5{\sim}7%$, respectively, which represents that the COD and DIN are the most prevalent pollutants among substances in the effluent through the sewage treatment plant. The current water quality of Asan Bay based on the observed COD, TN and TP concentrations ranks into the class II of the Korean standards for marine water quality but the water quality would deteriorate into class III in case that the disposal water by the sewage plant is discharged into the Bay.

• Economic and Environmental Geology
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• v.54 no.1
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• pp.151-160
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• 2021

2:1 clay minerals such as smectite incorporating ammonium were extracted to investigate the ammonium behavior and nitrogen isotope characteristics for two different sediment cores which were collected from shimmering sites on seafloor of the Wakamiko crater, southwestern Japan. Inorganic nitrogen contents in clay fraction were estimated by calibration curve based on consistently decreasing carbon and nitrogen ratio during the treatment to decompose organic materials, after removing inorganic carbon. The results show that the proportions of inorganic nitrogen for total nitrogen in clay fraction of SWS site(Core#1094MR: av. 18.2%) are higher than those in SES site(Core#1093MG: av. 11.5%). Relatively good crystallinity of the former suggests that exchangeable ammonium was transformed to non-exchangeable ammonium during more evolving diagenetic process. Nitrogen isotope variance of clay fraction(SES site: Core#1093MG: -4.4 ~ +0.2 ‰, av. -2.4 ‰; SWS site: Core#1094MR: -0.7 ~ +3.0 ‰, av. +1.5 ‰) during sequential decomposition of exchangeable ammonium suggests that heat flow derived from deep magma led to nitrogen isotope fractionation between dissolved ammonium and ammonia in the fluids involved in the formation of 2:1 clay mineral incorporating ammonium with local temperature variation.

• Proceedings of the Korean Aquaculture Society Conference
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• 2001.12a
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• pp.231-233
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• 2001

• Proceedings of the Korea Society of Environmental Biology Conference
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• 1995.05a
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• pp.12-12
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• 1995