• Journal of Bio-Environment Control
• /
• v.18 no.1
• /
• pp.40-45
• /
• 2009

The experiment has investigated the effects of growth, yield, fruit quality and cation absorption of strawberry 'Akihime' in different $NO_3-N:NH_4-N$ ratio in nutrient solution. $NO_3-N:NH_4-N$ ratios were 5.5:0, 4.0:1.5 and $3.0:2.5me{\cdot}L^{-1}$. As the ratio of $NH_4-N$ increased, pH was decreased by $5.0{\sim}6.0$ and EC sustained $0.8{\sim}1.0dS{\cdot}m^{-1}$ during experiment. Though in high $NH_4-N$ ratio of $3.0:2.5me{\cdot}L^{-1}$, the absorption of cations(K, Ca and Mg) was not inhibited. Treatment in contained $NH_4-N$ showed a tendency of increasing of petiole length and leaf width. The fruit length, fruit width, fruit weight and soluble solids were not significantly different. Yield per plant was lowest in $4.0:1.5\;me{\cdot}L^{-1}$, of $NO_3-N:NH_4-N$ ratio. Malformation fruit has not shown during the whole growth period.

• Journal of Bio-Environment Control
• /
• v.5 no.2
• /
• pp.120-130
• /
• 1996

Crisphead lettuce(Lactuca sativa L.) was grown in NFT to investigate the effects of NO$_3$-N and NH$_4$-N ratio in nutrient solution and elevated $CO_2$ treatment in the crisphead lettuce growth. This experiment has been conducted under three different ratios of NO$_3$-N:NH$_4$-N(100:0, 75:25, 50:50) with two $CO_2$ concentration (control, 1500ppm ). The results are as follows; 1. In the case of not controlling pH and EC in nutrient solution, pH was gradually increased in NO$_3$-N:NH$_4$-N=100:0 treatment but rapidly decreased in the nutrient solution 2. Daily changes of NO$_3$-N and NH$_4$-N were observed without controlling the nutrient solution. In the treatments of NO$_3$-N:NH$_4$-N ratios were 75:25 and 50:50, NO$_3$-N absorption rates were 27.7% and 26.1%, while NH$_4$-N absorption rates were 87.9% and 71.2%, respectively. 3. There was little differences in total nitrogen of leaves. However phosphorus, potassium, calcium and magnesium contents were highly shown in the treatment of $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. 4. Higher $CO_2$ assimilation rate was shown in plants grown under $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. It dropped significantly with the increase of NH$_4$- N rates in nutrient solution. 5. Fresh weight, leaf number, root length and root weight of crisphead lettuce were far better in the treatment of $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. Growth differences by $CO_2$ elevation were not shown in other NO$_3$-N:NH$_4$-N treatments. 6. The highest nitrate contents of leaves were shown in NO$_3$-N single treatment but shown the lowest vitamin C contents. Nitrate contents of leaves were decreased by $CO_2$ but the effect was slight treatment.

• Journal of Bio-Environment Control
• /
• v.3 no.2
• /
• pp.99-105
• /
• 1994

The objective of this study was conducted for elucidation of effects of the NO$_3$$^{[-10]}$ -N. NH$_4$$^{+}$-N ratio in the nutrient solution on the growth and quality of welsh onion(Allium fistulosum L.). The pH of nutrient solution increased in NO$_3$$^{[-10]}$ -N : NH$_4$$^{+}$-N ratio of 9 : 1 treatment, decreased in 1 : 1, 1 : 3 treatment, but was stable in 3 : 1 treatment during cultivation. The apparent growth of welsh onion was best in the treatment of 9 : 1(NO$_3$$^{[-10]}$ -N : NH$_4$$^{+}$-N ratio), however the treatment of 1 : 3 resulted in poor growth. The NO$_3$$^{[-10]}$ -N content of the plants increased in proportion to that content of nutrient solution. Pyruvic acid content of welsh onion was highest at 9 : 1, 3 : 1 treatment, and lowest at 1 : 3 treatment.tment.

• Journal of Bio-Environment Control
• /
• v.2 no.2
• /
• pp.119-125
• /
• 1993

The effect of NO$_3$-N and NH$_4$-N ratio on the growth of Perilla frutescens in deep flow culture was studied in winter season. NO$_3$-N and NH$_4$-N were treated in the ratios of 12 : 0, 9 : 3, 6 : 6(me/ $\ell$ ). The pH of the nutrient solution was increased an NO$_3$-N:NH$_4$-N=12 : 0 treatment, and decreased in the treatments containing NH$_4$-N, greatly in NO$_3$-N : NH$_4$-N = 6 : 6 treatment. The EC was increased regardless of treatments, but more increased in the treatments containing NH$_4$-N. The stem-base circumference, plant height, root weight, shoot weight, and yields of leaves were by far the highest in NO$_3$-N:NH$_4$-N=6 : 6 treatment and the lowest in NO$_3$-N:NH$_4$-N= 12 : 0 treatment. Among the mineral contents of leaves, N, K, Fe and P were higher in the treatments containing NH$_4$-N. Ca, Mg and Mn were higher in NO$_3$-N :NH$_4$-N= 12 : 0 treatment.

• ALGAE
• /
• v.32 no.4
• /
• pp.275-284
• /
• 2017

Microcystis aeruginosa causes harmful algal blooms in the Nakdong River of Korea. We studied the effect of different concentrations and ratios of ammonium ($NH_4{^+}$), nitrate ($NO_3{^-}$), and phosphate ($PO{_4}^{3-}$) on growth of this species in BG-11 medium: each nutrient alone, $NO_3{^-}:NH_4{^+}$ ratio, the N : P ratio with fixed total N (TN), and the N : P ratio with fixed total P (TP). The single nutrient experiments indicated that M. aeruginosa had the highest growth rate at $NH_4{^+}$ and $NO_3{^-}$ concentrations of $500{\mu}M$, and at a $PO{_4}^{3-}$ concentration of $5{\mu}M$. The $NO_3{^-}:NH_4{^+}$ ratio experiments showed that M. aeruginosa had the highest growth rate at a ratio of 1 : 1 when TN was $100{\mu}M$ and $250{\mu}M$, and the lowest growth rate at a ratio of 1 : 1 when the TN was $500{\mu}M$. The N : P ratio with fixed TN experiments indicated that M. aeruginosa had the highest growth rates at 50 : 1, 20 : 1, and 100 : 1 ratios when the TN was 100, 250, and $500{\mu}M$, respectively. In contrast, the N : P ratio with fixed TP experiments showed that M. aeruginosa had the highest growth rates at 200 : 1 ratio at all tested TP concentrations. In conclusion, our results imply that the $NO_3{^-}:NH_4{^+}$ ratio and the $PO{_4}^{3-}$ concentration affect the early stage of growth of M. aeruginosa. In particular, our results suggest that the maximum growth of M. aeruginosa is not simply affected by the $NO_3{^-}:NH_4{^+}$ ratio and the N : P ratio, but is determined by the TN concentration if a certain minimum $PO{_4}^{3-}$ concentration is present.

• Journal of Bio-Environment Control
• /
• v.1 no.1
• /
• pp.21-27
• /
• 1992

The effects of different night temperatures and NO$_3$$^{[-10]}$ : NH$_4$$^{+}$ ratios in nutrient solution on the growth and quality of Chinese white cabbage(B. chinensis L. var. chinensis) and Chinese flat cabbage(B. chinensis L. var. rosularis) were studied. The results were summarized as follows. 1. Fresh weight was increased higher in night temperature 15$^{\circ}C$ than 5, 1$0^{\circ}C$, but content of vitamin C and dry weight ratio were increased as night temperature was lower. 2, The growth of Chinese white cabbage and Chinese flat cabbage was bad extremely in NO$_3$$^{[-10]}$ : NH$_4$$^{+}$(0 : 8), and the others were little different 3. In nutrient solution, the higher NO$_3$$^{[-10]}$ -N concentration was, the more content of vitamin C, and the higher NH$_4$$^{+}$-N concentration was, the more dry weight ratio.ratio.

• Korean Journal of Soil Science and Fertilizer
• /
• v.43 no.4
• /
• pp.424-429
• /
• 2010

To solve the problems with excessive accumulation of soil inorganic N and resulting saline soils from overuse of nitrogen fertilizer, the effect of sucrose application on decrease of soil inorganic N content and electrical conductivity (EC) was studied. Sucrose treatment greatly reduced ${NH_4}^+$-N content in soil. The amount of reduction was greater as the amount of sucrose treatment was increased. When ${NH_4}^+$-N content was reached the lowest point (about 10 mg $kg^{-1}$or lower), the C/N ratio, which determines the amount of sucrose treatment, was around 10 regardless of initial ${NH_4}^+$-N content. For the rate of ${NH_4}^+$-N reduction 15~36 hours was required to reduce the initial ${NH_4}^+$-N content to half, and 36~69 hours to lower ${NH_4}^+$-N content to the lowest point (about 10 mg $kg^{-1}$or lower). In addition, sucrose treatment greatly lowered ${NO_3}^-$-N content. In case of C/N ratio above 10, initial ${NO_3}^-$-N content of 348 mg $kg^{-1}$ was reduced to the lowest of 14~21 mg $kg^{-1}$. As for the rate of ${NO_3}^-$-N reduction by sucrose treatment, it took 36~60 hours for ${NO_3}^-$-N content to reach the lowest point for C/N ratio of 10 or higher, and it took 3 weeks, comparably longer time, for C/N ratio of 5. Lowering soil EC from sucrose treatment showed the same trend as ${NO_3}^-$-N content. As an important energy and carbon source for humankind, sugar should not be wasted and must be carefully applied to soil. In principle, the best way of preventing salt accumulation in soil is to optimize the fertilizer input. However, when over-fertilization should be dealt with, the sucrose treatment would be a possible and effective counter-measure to reduce overdosed nitrogen sources in soil.

• Journal of Bio-Environment Control
• /
• v.10 no.1
• /
• pp.50-54
• /
• 2001

Effect of NO$_3$:NH$_4$ratio and pH of nutrient solution on nitrate content of leaves was investigated for leaf lettuce(Lactuca sativa L.) grown by a deep flow technique. Ratios(in me.L$^{-1}$ ) of NO$_3$:NH$_4$tested were 12:1, 10:3 and 8:5. The treatment of 8:5 NO$_3$:NH$_4$ratio had two solutions, one with uncontrolled pH and the other with automatically controlled pH. Solution pH continuously increased in 12:1 NO$_3$:NH$_4$treatment. Solution pH decreased gradually more as NH$_4$ratio increased. Treatment of 8:5 NO$_3$:NH$_4$with automatic pH control satisfactorily maintained the solution pH in the range of pH 5.5-6.0. Nitrate content in leaves was the greatest in treatment of 12:1 NO$_3$:NH$_4$ and the least in treatment of 8:5 NO$_3$:NH$_4$with automatic pH control. Fresh weight decreased in treatments of 10:3 and 8:5 NO$_3$:NH$_4$, whereas it increased in treatments of 12:1 and 8:5 NO$_3$:NH$_4$with pH control. It was concluded that the growth and leaf nitrate content were the greatest in high NH$_4$treatment with automatic pH control.

• Journal of Korean Society on Water Environment
• /
• v.22 no.4
• /
• pp.599-604
• /
• 2006

Nitrogen removal with the combined SHARON (Single reactor system for high ammonium removal over nitrite)ANAMMOX (Anaerobic ammonium oxidation) process using the effluent of ADEPT (Anaerobic digestion elutriated phased treatment) slurry reactor with very low C/N ratio for piggery waste treatment was investigated. For the preceding SHARON reactor, ammonium nitrogen loading and removal rate were $0.97kg\;NH_4-N/m^3_{reactor}/day$ and $0.68kg\;NH_4-N/m^3_{reactor}/day$ respectively. In steady state, bicarbonate alkalinity consumption for ammonium nitrogen converted to $NO_2-N$ or $NO_3-N$ was 8.4 gram per gram ammonium nitrogen. The successive ANAMMOX reactor was fed with the effluent from SHARON reactor. The loading and removal rate of the soluble nitrogen defined as the sum total of $NH_4-N$, $NO_2-N$ and $NO_3-N$ in ANAMMOX reactor were $1.36kg\;soluble\;N/m^3_{reactor}/day$ and $0.7kg\;soluble\;N/m^3_{reactor}/day$, respectively. The average $NO_2-N/NH_4-N$ removal ratio by ANAMMOX was 2.41. Fluorescence in situ hybridization (FISH) analysis verified that Candidatus Kuenenia stuttgartiensis were dominate, which means that they played an important role of nitrogen removal in ANAMMOX reactor.

• Korean Journal of Microbiology
• /
• v.39 no.1
• /
• pp.21-26
• /
• 2003

Ninety strains of photosynthetic bacteria were isolated from a local stream at Kyonggi-do, Korea and were further screened. Using these isolated strains, experiments were performed under various light and oxygen conditions in order to select strains with high nitrogen $(NH_3-N,\; NO_3^--N)$ removal efficiencies. Results showed that all the strains screened removed $NH_3-N$, the light had no effect on nitrogen removal, and the nitrogen removal rate was higher aerobically than anaerobically. The removal of $NO_3^--N$ was showed up to 35.3% in some specific strains. Results of batch experiments using Rhodocyclus gelatinosus, an isolated strain with a superior removal rate of $NH_3--N$ and $NH_3-N$, under the anaerobic condition, showed that the removal rate of organics and $NH_3-N$ was the highest (98.2 and 89.0%, respectively) at the CODcr (mg/L)/biomass (mg/L) ratio of 0.2, and the $NH_3-N$ concentration did not increase with the decreasing $NH_3-N$ concentration. Experimental results from various C/N ratios confirmed that the effective removal rate (75.8%) of $NH_3-N$ occurred even at the low (5:1) C/N ratio as well as high ratios, and the simulataneous removal of $NO_3^--N$ (96.0%).