• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.3
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• pp.220-225
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• 2013

This experiment was carried out to elucidate the effects of silicate and different application forms of N on the uptake of water and N by rice plants. Three rice cultivars, Ilpum, Anda and M202, were grown under the hydroponics in a phytotron. One-hundred ppm silica was applied for silicate treatment. For nitrogen application forms were 100% $NH_4$ and $NH_4+NO_3$ in 2:1 ratio were applied. Silica treatment, compared to silica free, was very effective on the nitrogen uptake and dry weight increase of rice plants. Although silica application demonstrated no significant effect on the amount of water uptake, it improved increased water and nitrogen use efficiency. Therefore, sufficient application of silicate in paddy field will be useful for the growth of rice plants and water saving.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.4
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• pp.522-527
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• 2010

Gibberellic acid ($CA_3$) is used in many industries and constitutes the primary gibberellins produced by fungi and bacteria. However, there is no information on $CA_3$ production by Methylobacterium oryzae CBMB20, a novel plant growth promoting bacterium. We investigated the favorable carbon (C) and nitrogen (N) sources and ratios and cultural conditions, such as incubation temperature, pH of the culture medium, and incubation period for the maximum production of $CA_3$ by Methylobacterium oryzae CBMB20. Maximum $CA_3$ production was observed in ammonium mineral salt (AMS) broth supplemented with Na-succinate and $NH_4Cl$ as C and N sources, respectively. The maximum $CA_3$ production was found at the C/N ratio of 5:0.4 g $L^{-1}$. The highest $CA_3$ production was obtained when the bacterial culture was incubated at $30^{\circ}C$ for 96 h at pH 7.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.65-71
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• 2013

This research was conducted to evaluate the influence of $NO_3{^-}:NH_4{^+}$ ratios in fertilizer solution on the vegetative growth and fruit yield of hot pepper (Capsicum annuum L.) through pot cultivation. The Hoaglad's solution was modified to contain various $NO_3{^-}:NH_4{^+}$ ratios such as 100:0 (A), 73:37 (B), 50:50 (C), 27:73 (D), 0:100 (E), and no nitrogen (F). Plants were transplanted into root substrates and the modified solutions were applied as plant needed in plastic house. There were no statistical significances among the treatments from A through D in the fresh and dry weights, and number of leaves 31 days after transplanting, but elevation of $NH_4{^+}$ ratios in the solution decreased the fresh fruit weight 62 days after transplanting with statistical differences. In the results of inorganic element analysis based on the dry weight of fully expanded mature leaves, N and P contents as well as micro cations such as Fe, Mn, Zn, and Cu increased as $NH_4{^+}$ ratios were elevated 62 days after transplanting. However, those of macro cations such as K, Ca, and Mg resulted in decreasing tendency. The elevation of $NH_4{^+}$ ratios in fertilizer solution resulted in the increase of EC and total N concentrations ($NO_3{^-}+NH_4{^+}$), but this decreased the pH as well as Ca and Mg concentrations in soil solution 62 days after transplanting. The K concentration in soil solution was the highest in the treatments of C and followed by D, B, E, and A. The above results indicate that the proper $NO_3{^-}:NH_4{^+}$ ratio in the nutrient solution is 73:27 (B) or 100:0 (A) and the B solution is proper for the vegetative growth and that of A is proper for reproductive growth stage.

• Journal of environmental and Sanitary engineering
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• v.14 no.1
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• pp.11-16
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• 1999

This study was performed to investigate THMs formation by chloramination as a secondary disinfection in drinking water distribution system. As the $Cl_2/NH_3-N$ ratio increased from 1:1 to 4:1, the THMs concentration had actually no change in the breakpoint curve of pH 6, 7. At pH 8, THMs level was not augmented at between 1:1 and 5:1. In the $Cl_2/NH_3-N$ ratio of more than 5:1 and 6:1 respectively, THMs level was raised. Only the chloroform of THMs was insignificantly detected by both preformed chloramine and preammoniation applications, which was probably attributed to the stoichiometrically unstable equilibrium in the preparation of chloramine, whereas $CHCl_3$, $CHCl_2Br$ and $CHClBr_2$ of THMs were found in the application of free chlorine. However it turned out that the THMs levels by chloramine was incomparably inferior to that of free chlorine.

• KSBB Journal
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• v.24 no.2
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• pp.195-200
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• 2009

The effect of nitrogen source on cell growth and benzo[c]phenanthridine alkaloids production by modifying $NO_3\;^-:NH_4\;^+$ ratio in cell suspension culture of Eschscholtzia califarnica was investigated. When total nitrogen concentration is maintained (60 mM), maximum benzo[c]phenanthridine alkaloids production is about 60.72 mg/L at 50:10 (mol/mol). This productivity was 3.8 times higher than that obtained when cells were grown instandard MS medium. The decrease of $NO_3\;^-:NH_4\;^+$ ratio at 60 mM of total nitrogen caused the decline of both growth and benzo[c]phenanthridine alkaloids production. Under the same concentration of $N0_3\;^-$ (50 mM), higher concentration of $NH_4\;^+$ inhibited cell growth strongly but induced alkaloids production slightly. Also, under the same concentration of $NH_4\;^+$ (25 mM), higher concentration of $N0_3\;^-$ induced alkaloids production strongly but high concentration of $N0_3\;^-$ (${\geq}$100 mM) interfered alkaloids instead. Maximum benzo[c]phenanthridine alkaloids production is about 62.71 mg/L at 50:25 (mol/mol). These results suggest that higher biomass and higher alkaloids production could be obtained by optimizing each nitrogen concentration as well as $NO_3\;^-:NH_4\;^+$ ratio in the culture medium. Nitrate and ammonium in culture medium have distinct role in the regulation of growth and alkaloids production; ammonium had a strong influence on growth while nitrate had an influence on alkaloids production.

• Journal of Animal Science and Technology
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• v.51 no.4
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• pp.337-342
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• 2009

The feasibility of reutilization of magnesium ammonium phosphate (MAP) or struvite slurry recovered from the process through microwave irradiation was studied in this experiment. For this purpose, 4 different operations were performed with or without Mg source addition and different levels of MAP recycled in a batch reactor. Dissolution rate of MAP, ${NH_4}^+$ elimination pattern and physicochemical changes of MAP during microwave irradiation were also studied. The result showed that only 33% orthophosphate ($PO_4-P$) and 27% $NH_4-N$ removal occurred without adding any external Mg source (run A), whereas 87% $PO_4-P$ and 40% $NH_4-N$ removed when 1.0 M ratio of $MgCl_2$ (run B) was added based on $PO_4-P$ in influent. Although the addition of 1.0 molar ratio of microwave irradiated MAP (Run C) removed lower $PO_4-P$ and $NH_4-N$ than 1.0 M $MgCl_2$ (run B), $PO_4-P$ removal was double when compared with no Mg addition (run A). Addition of half MAP and half $MgCl_2$ (run D) showed the similar removal efficiency (88% $PO_4-P$ and 35% $NH_4-N$) with sole $MgCl_2$ addition (run B). Based on these results, the reutilization of MAP irradiated by microwave would be a feasible way to enhance the removal efficiencies of N and P, as well as curtail the Mg chemical usage. Track study showed that $NH_4-N$ gradually increased at initial stage of microwave irradiation of MAP, and then started eliminating from liquor as temperature increased over $45^{\circ}C$. Dissolution rate of ${PO_4}^{-3}$ during microwave irradiation was proportional to the initial MAP concentration, having $0.0091x^{0.6373}$ mg/sec. It was found from the scanning electron microscope (SEM) study that physical structure of MAP crystal started breaking down into small cube granules within very short time by electromagnetic vibration force during microwave irradiation and then gradually melted down into solution.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.2
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• pp.121-126
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• 1993

The behaviors of inorganic nitrogen derived from solid animal waste in soil has been received too much concern partly because nitrate which occurred from nitrification can act as a pollutant to soil and groundwater and partly because the loss of nitrogen from surface soil by downward movement of water is disadvantageous in the view of plant nutrient. This present study was conducted to get fundamental imformations on nitrogen behavior and to provide improved basical concepts on the management of animal waste. Fresh or fermented pig manure was mixed with a sandy loam soil in the ratio of 2:1(soil:pig manure), packed into test tube and incubated at $30^+/-1^{\circ}C$ for 8 weeks under aerobic- or anaerobic condition. Sample tubes were taken at the one week interval and analyzed on pH, the amount of $CH_4$ produced under anaerobic condition and inorganic nitrogen. The pH of soil treated with fresh pig manure under anaerobic condition was lowered by 1.87 unit compared to that of under aerobic condition, but at the treatment with fermented pig manure, pH change was very little between aerobic and anaerobic condition. The coefficients of regressional equations which were obtained from pH and incubation time were -0.114 in fresh pig manure and -0.089 in fermented pig manure, and the extent of pH decrease due to incubation was greater in fresh pig manure than that of fermented pig waste. No differences in the amounts of $CH_4$ produced under anaerobic condition between fresh and fermented pig manure was observed until 3 weeks of incubation, however, after that the amount of $CH_4$ produced in fresh pig manure was abruptly increased and cumulative amont of $CH_4$ was reached 8.6 mole/g. K values on $CH_4$ production in fresh and fermented pig manure was 0.211 mole/g/day and 0.046 mole/g/day, respectively, for 5 weeks from the 3rd to the 8th week. $NH_4-N$ concentration at aerobic condition with fresh pig manure treatment was lowered by passing time of incubation, but $NO_3-N$ concentration was elevated from 11.2 ppm at initial state to 67.3 ppm after incubation and this trend on $NH_4-N$, $NO_3-N$ concentration was very similar to the treatment of fermented pig manure. While $NH_4-N$ concentration under anaerobic condition was greatly increased. $NO_3-N$ concentartion was not only very low but also no great changes, that was ranged from 4 to 8 ppm.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.E1
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• pp.29-36
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• 2002

The selective catalytic reduction (SCR) reaction of promoter catalysts was investigated in this study. A pure anatase type of TiO$_2$ was used as support. Activation measurement of prepared catalysts was practiced on a fixed reactor packing by the glass bead after filling up catalysts in 1/4 inch stainless tube. The reaction temperature was measured by K-type thermocouple and catalyst was heated by electric furnace. The standard compositions of the simulated flue gas mixture in this study were as follows: NO 1,780ppm, NH$_3$1,780ppm, $O_2$1% and $N_2$ as balance gas. In this study, gas analyzer was used to measure the outgassing gas. Catalyst bed was handled for 1hr at 45$0^{\circ}C$, and the reactivity of the various catalyst was determined in a wide temperature range. Conversion of NH$_3$/NO ratio and of $O_2$ concentration was practiced at 1,1.5 and 2, respectively. The respective space velocity were as follows . 10,000, 15,000 and 17,000 hr-1. It was found that the maximum conversion temperature range was in a 5$0^{\circ}C$. It was also found toi be very sensitive at space velocity, $O_2$ concentration, and NH$_3$/NO ratio. We also noticed that the maximum conversion temperature of (W, Mo, Sn) -V$_2$O$_{5}$/TiO$_2$ catalysts was broad. Specially WO$_3$-V$_2$O$_{5}$TiO$_2$2 catalyst appeared nearly 100% conversion at not only above 30$0^{\circ}C$ ut also below 25$0^{\circ}C$. At over 30$0^{\circ}C$, NH$_3$ oxidation decreased with decrease of surface excess oxygen. In addition, WO$_3$-V$_2$O$_{5}$TiO$_2$ catalyst did not appear to affect space velocity, $O_2$ concentration, and NH$_3$/NO ratio.ratio.

• Journal of Korean Society of Forest Science
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• v.82 no.3
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• pp.246-253
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• 1993

The composition of the nitrogen forms of the organic layer and mineral soil horizons of 8 differing soil type was measured to find a clue to elucidate the problem on the fertility and nitrogen availabilities of forest soils. The ratio of inorganic $N(NH_4-N+NO_3-N)$ to total N was very low in every 0 layer and its maximum was only about 2%. And the inorganic N concentration of every mineral soil horizon was low, and the maximum of its rate to N was 3.7% in surface horizon and about 4.1% in lower horizon. Organic N form of O layer were characterized by the decrease of aminoacid-N, and the increased of hexosamine-N and amide-N according to the advance of decomposing process. The ranges of hydrolyzable-N of every flesh litter, F and H layer of the selected soils were about 80-90% and they- were hardly affected by the differences of tree species and decomposing process. The organic N form of every litter was similar and it was follows : aminoacid-N was not abundant and it ranges were about 40-50%, more than half of hydrolyzable-N. The hexosamine-N was eery poor and it ranged to only 2-7%. The amide-N teas low and about 10-23%. No distinguished difference was seen between the organic N forms of the O layer and surface horizon of dry and wet soils in brown forest soils.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.51-62
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• 2010

The high concentration of N in the wastewater from livestock farming generally renders the efficiency of the wastewater treatment. Therefore, removal of N in livestock wastewater is crucial for successful treatment. The current study was conducted to investigate the optimum conditions for partial nitrification under anaerobic condition following nitritation in TPAD-BNR(two-phase anaerobic digestion-biological nitrogen removal) operating system. Sequential operating test to stimulate partial nitrification in reactor showed that partial nitrification occurred at a ratio of 1.24 in $NO_2{^-}$-N:$NH_4{^+}$-N. With this result, a wide range of factors affecting stable nitritation were examined through regression analysis. In the livestock wastewater treatment procedure, the hydraulic retention time (HRT) and pH range for optimum nitrite accumulation in the reactor were 1-1.5 days and 7-8, respectively. It was appeared that accumulation of $NO_2{^-}$-N in the reactor is due to inhibition of the $NO_2{^-}$-N oxidizer by free ammonia (FA) while the effect of free nitrous acid was minimal. Nitrification was not influenced by DO concentration at a range of 2.0-3.0 mg/L and the difference in the growth rate between $NH_4{^+}$-N oxidizer and $NO_2{^-}$-N oxidizer was dependent on the temperature in the reactor.