• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.571-576
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• 2004

Since anaerobic/anoxic/oxic process, which is a typical mainstream biological nitrogen and phosphorus removal process, utilizes influent organic matter as an external carbon source for phosphorus release in anaerobic or anoxic stage, influent COD/T-P ratio gives a strong influence on performance of phosphorus removal process. In this study, a bench scale experiment was carried out for SBR process to investigate nitrogen and phosphorus removal at various influent COD/T-P ratio and nitrate loadings of 23~73 and 1.6~14.3g $NO_3{^-}-N/kg$ MLSS, respectively. The phosphorus release and excess uptake in anoxic condition were very active at influent COD/T-P ratios of 44 and 73. However, its release and uptake was not obviously observed at COD/T-P ratio of 23. Consequently, phosphorus removal efficiency was decreased. In addition, the phosphorus release and uptake rate in anoxic condition increased as the nitrate loading decreased. Specific denitrification rate had significantly high correlation with organic materials and nitrate loadings of the anoxic phase too. The rate of phosphorus release and uptake in the anoxic condition were $0.08{\sim}0.94kg\;S-P/kg\;MLSS{\cdot}d$ and $0.012{\sim}0.1kg\;S-P/kg\;MLSS{\cdot}d$, respectively.

• Korean Journal of Environmental Agriculture
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• v.40 no.4
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• pp.359-365
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• 2021

BACKGROUND: Prohexadione-calcium (PC) is a plant growth regulator of cyclohexanedione family acting on inhibiting gibberellin biosynthesis and has been used to regulate shoot elongation of turfgrass in the golf course during the summer season. This study was conducted to investigate the effects of PC on the inhibition of shoot elongation, growth, and nitrogen uptake in Zoysia matrella. METHODS AND RESULTS: Treatments were as follows; non-treatment, control (TE 0.01 a.i. g/m²/100 mL), 0.0025PC (PC 0.0025 a.i. g/m²/100 mL), 0.005PC (PC 0.005 a.i. g/m²/100 mL), 0.01PC (PC 0.01 a.i. g/m²/100 mL) and 0.02PC (PC 0.02 a.i. g/m²/100 mL). Visual quality and chlorophyll content were not significantly different. As compared to non-treatment, shoot length and clipping yield in 0.005PC, 0.01PC and 0.02PC treatments were decreased by 29-36% and 65-82%, respectively, and those of 0.0025PC were not significantly different. N uptake of Z. matrella after applying PC was decreased by 28.9-77.8% than that of non-treatment. Inhibition effects of PC treatment in Z. matrella were not significantly different from those of control. CONCLUSION(S): These results indicated that the application of prohexadione calcium inhibited shoot elongation, clipping yield and N uptake amount in Z. matrella, and trinexapac-ethyl could be replaced with prohexadione-calcium in turfgrass management.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.3
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• pp.146-152
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• 1987

Sorghum cv. Pioneer 93 1, sorghum-sudangrass hybrid cv. Sioux and maize plant cv. Blizzard were assayed for toxic concentrations of nitrate-nitrogen ($NO_3$-N) and their relationship to morphological characteristics and environmental temperature in a field and phytotron trial. In the phytotron, sorghum and maize plants ranging from emergence to heading stage, were grown under different day/night temperatures of 30125, 25/20,28/18 and 1818 degree C. Nitrate-nitrogen in sorghum and maize plants was accumulated mainly in stems. Therefore nitrate concentration in the young plants was increased as development of stalks advanced and was highest at the stage of 3-4 leaves, when the plants had a leaf weight ratio 0.78-0.80 g/g plant weight. However, nitrate concentrations of the plant decreased as morphological development progressed, especially from the stage of growing point differentiation. Correlation coefficients showed a positive correlation of nitrate concentration with leaf weight ratio, leaf area ratio and specific leaf area, while plant height, dry matter percentage and absolute growth rate showed a negative association with TEX>$NO_3$-N ($P{\le}0.1$%). Cyanogenic glycosides, total nitrogen and crude protein were close associated with nitrate accumulation, and positively significant ($P{\le}0.1$%). High temperature over 30/25^{\circ}C.$ for 3 weeks increased N-uptake and dry matter accumulation, but reduced nitrate concentration. Under cold temperature below 18/8^{\circ}C.$ concentration of nitrate-N was increased in spite of its limited nitrogen uptake and plant growth.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.566-571
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• 2006

A sequencing batch biofilm reactor (SBBR) operated with a cycle of anaerobic - aerobic - anoxic - aerobic has been evaluated for the nutrient removal characteristics. The sponge-like moving media was filled to about 10% of reactor volume. The sewage was the major substrate while external synthetic carbon substrate was added to the anoxic stage to enhance the nitrogen removal. The operational results indicated that maximum T-N and T-P removal efficiencies were 97% and 94%, respectively were achieved, while COD removal of 92%. The observations of significant nitrogen removal in the first aerobic stage indicated that nitrogen removal behaviour in this SBBR was different to conventional SBR. Although the reasons for aerobic nitrogen removal has speculated to either simultaneous nitrification and denitrification or anoxic denitrification inside of the media, further researches are required to confirm the observation. The specific oxygen uptake rate (SOUR) test with biofilm and suspended growth sludge indicated that biofilm in SBBR played a major role to remove substrates.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1031-1037
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• 2006

In order to improve water quality of the Juam Lake, a constructed wetland was implemented and operated for 2 years with the effluent of sewage treatment plant and diffuse pollutant discharged from agricultural area. During the summer season, average removal efficiencies for BOD and SS were 15.8% and 39.4%, respectively. Due to the mixed effect of vegetation, soil microbes and sediments, the higher nutrient removal efficiencies were obtained: average T-N and T-P removal efficiencies were 64.2% and 71.7%, respectively. The concentration of sediment was increased initially, and maintained constant throughout monitoring period. The highest nitrogen and phosphorus uptake were observed in Phragmites japonica. The nitrogen uptake was estimated as 0.235 DW mg/g while phosphorus uptake was estimated as 2.059 DW mg/g.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.152-157
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• 1988

The effect of gypsum application was tested on dry matter yield, sulfur uptaken, composition of Ritrogen compound and sulhr compound and sulfur balance in mixed pasture. Total dry matter yields and sulfur uptake by grasses increased with the increasing of gypsum application rates. The ratios between total nitrogen and total sulfur in masses decreased with the increase of sulfur uptake at 2nd and 3rd cutting times. Cysteine content was little affected by gypsum while methionine content slightly increased an 4.0, 6.0 kg3 per 10a levels at 2nd and 3rd cutting times. The uptake of nitrate nitrogen decreased with gypsum application and dry matter digestibility increased about 1.1 to 3.3%. The soil pHs after experiment become high in surface and subsoil till 6.0 kg.S per 10a, but low at 10.0 kg.S per 10a. The content of sulfur in surface soil was 19.9 ppm after experiment, but very high in subsoi1,ranging from 94 to 143 ppm.S. Sulfur leached from the surface soil by 0.69, 2.39, and 6.24 kg.S per 10a in the plots of 4.0, 6.0, and 10.0 kg.S per 10a, respectively.

• Korean Journal of Environmental Agriculture
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• v.42 no.2
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• pp.152-158
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• 2023

This study was conducted to evaluate the effects on soil chemical properties and plant growth after applying soldier fly compost (SFC). Treatments were as follows. No fertilizer (NF), control, SFC1 (SFC 250 kg/10a), SFC2 (SFC 500 kg/10a) and SFC3 (SFC 1,000 kg/10a). As compared to control in the pot test, organic matter (OM) and exchangeable sodium (Ex-Na) of SFC3 treatment were increased, and growth and nutrient uptake of young radish were not significantly different. Correlation coefficient between soil chemical factors like total nitrogen (T-N), OM, and CEC and uptake of nitrogen (N) and phosphorus (P) was significantly positive (p≤0.05). Compared to control in the field test, electrical conductivity, T-N, OM, Av.-P₂O₅, and CEC was increased, and lettuce growth was not significantly different. Correlation coefficient between application amount of SFC and T-N, OM, and Av.-P₂O₅ was significant positively (p≤0.05). These results indicated that the application of SFC improved nutrient availability of soil by increasing OM and CEC.

• ALGAE
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• v.17 no.4
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• pp.249-257
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• 2002

• Korean Journal of Microbiology
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• v.26 no.2
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• pp.129-136
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• 1988

To investigate the influence of cosubstrate supplement and ammonium sulfate on lignin degradation by Pseudomonas diminuta KM-4-2, isolated in the laboratory, the strain was cultured on the lignin media which contained lignin as a source of carbon and the culture filtrate was analyzed by Sephadex G-75 column chromatography. It was found that polymerization was not appeared unlike wood-rot fungi. When the carbohydrates were added, the peak of lignin at 280nm by UV scanning spectra of the filtrate, was significantly increased. In order to determine the effect of ammonium sulfate on the ligninolytic activity, the isolated strain was incubated in the media containing 0.1%, 0.25% and 0.5% of nitrogen concentration in the Warburg flask and the rate of oxygen uptake was esitmated by Warbuge Respirometer. As a result, the activity was maximum at 0.1% of nitrogen concentration and thereafter decreased in parallel with nitrogen concentration.

• BMB Reports
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• v.56 no.2
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• pp.56-64
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• 2023

Nitrogen (N) is an essential macronutrient required for plant growth and crop production. However, N in soil is usually insufficient for plant growth. Thus, chemical N fertilizer has been extensively used to increase crop production. Due to negative effects of N rich fertilizer on the environment, improving N usage has been a major issue in the field of plant science to achieve sustainable production of crops. For that reason, many efforts have been made to elucidate how plants regulate N uptake and utilization according to their surrounding habitat over the last 30 years. Here, we provide recent advances focusing on regulation of N uptake, allocation of N by N transporting system, and signaling pathway controlling N responses in plants.