• Environmental Engineering Research
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• v.18 no.4
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• pp.235-239
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• 2013

In the present investigation, the efficiency of Chlorella vulgaris (C. vulgaris) was evaluated for the removal of ammonia-nitrogen from wastewater. Eight different wastewater samples were prepared with varied amounts of $NH_4-N$ concentrations from 15.22 to 205.29 mg/L. Experiments were conducted at pH $7.5{\pm}0.3$, temperature $25^{\circ}C{\pm}1^{\circ}C$, light intensity $100{\mu}E/m^2/s$, and dark-light cycles of 8-16 hr continuously for 8 days. From the results, it was found that $NH_4-N$ was completely removed by C. vulgaris, when the initial concentration was between 5.22-25.24 mg/L. However, only 50% removal was obtained when the $NH_4-N$ concentration was 85.52 mg/L, which further decreased to less than 32% when the $NH_4-N$ concentration exceeded 105.43 mg/L. The further influence of nitrogen on chlorophyll was studied by various $NH_4-N$ concentrations. The maximal value of chlorophyll a (Chl a) content was found to be 19.21 mg/L for 65.79 mg/L $NH_4-N$ concentration, and the maximum specific $NH_4-N$ removal rate of 1.79 mg/mg Chl a/day was recorded at an $NH_4-N$ concentration of 85.52 mg/L. These findings demonstrate that C. vulgaris could potentially be employed for the removal of $NH_4-N$ from wastewater.

• Korean Journal of Medicinal Crop Science
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• v.23 no.4
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• pp.277-283
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• 2015

This study was conducted to investigate the selected chemical properties of soils in Saururus chinensis Baill (Chinese lizard's tail) cultivation fields to provide optimal fertilizer application rates and to examine the growth and pharmaco-consitituents of Saururus chinensis Baill as influenced by different amounts of nitrogen (N) fertilizer applications. Based on the results of selected soil chemical properties in 37 cultivation sites of the plant, soil pH, organic matter content, and exchangeable $K^{+}$ concentration were lower than optimal values for cultivating general medicinal crops even though relatively high standard deviations were found in some of the values. At the harvesting stage of the plant aerial parts, soil pH, electrical conductivity (EC), available $P_2O_5$, and exchangeable $Ca^{2+}$, $Mg^{2+}$, $Na^{+}$ decreased as comparing with those before transplanting the plant, whereas the concentration of exchangeable $K^{+}$ increased in the plot treated with N 100% and compost. Fresh weight of the plant aerial parts were highest, 492.5kg/10, in the N 100% treatment plot. Correlation equation between N levels treated (X) and yield of the plant aerial parts (Y) presented as $Y=-2.1609X^2+30.082X+344.12$($R^2= 0.7113$) and the optimal rate of N fertilizer application for the plant was 6.6kg/10a. Carbon concentrations in the plant were not different among the different N levels applied. N and K concentrations in the plant were highest in the plot of N 100% with compost applications, the highest P concentration was in N 100% plot, and the highest Ca and S concentrations were in N 200% plot. Quercetin and quercitrin were highest in the N 150% plot and tannin was highest in N 100% or N 100% with compost application plot.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.2
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• pp.169-176
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• 2013

Preharvest sprouting seriously reduces milling and baking quality of hard winter wheat (Triticum aestivum L.) grain. To determine the effect of nitrogen fertilizer application on decreasing of preharvest sprouting, several levels of N-fertilization were conducted in two winter wheat cv. Keumkang and Jokyung, grown in Iksan. Nitrogen fertilization is used to increase grain yield and protein content. Grain yield increased at 108kg/ha (50% increased nitrogen to the standard) application and decreased as more nitrogen was applied. There was a linear increase in grain protein contents with increasing level of nitrogen application. Germination rate, germination index and ABA sensitivity were gradually reduced by increasing of nitrogen application level. Preharvest sprouting showed a significantly correlation to germination rate but could not be correlated to protein content and falling number. A significant positive correlation was detected between preharvest sprouting and different additional nitrogen fertilizer levels.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.3
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• pp.169-178
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• 2003

This pot experiment was conducted to find out the effects of boron application($B_{0}$ ; control, $B_1$; 0.2, $B_2$; 2.0, B$_3$; 6.0, $B_4$; 15.0 boron me/pot) on the forage performance of pure and mixed cultures of orchardgrass and white clover. The third part was concerned with the changes in the contents and yields of nitrogen compounds(crude/pure protein and soluble N-compound) in forages. The results obtained are summarized as follows: 1. With no additional fertilization, especially nitrogen, in a pure culture, the $B_{0}$ and $B_4$ treatments on white clover decreased the amount of crude/pure protein, and showed nitrogen deficiency symptoms. However, the optimum boron application($B_2$) positively resulted in the increase of crude and pure protein, especially pure protein, and the content ratio of pure protein/soluble N-compounds. With additional fertilization, especially nitrogen, differences were not found among the boron treatments($B_{0}$, $B_2$, and $B_4$). 2. Owing to the decline of white clover as affected by the additional fertilization, especially nitrogen, in the grass-clover mixed cultures, the effects of B-application on these contents of white clover were different and relatively low, compared with the pure cultures. But the positive effect of $B_2$ treatment tended to be similar to the pure cultures. Also, it was recognized that the $B_2$ treatment resulted in the increase of their contents in orchardgrass, however, the effect was relatively minor compared with that of white clover. 3. The optimum B application(B$_2$) on white clover influenced relatively better on the yields of crude and pure protein than on the dry matter yields, especially with no additional fertilization. The effects of boron application on the contents and yields of crude and pure protein were different according to the forage species, whether it was a pure or mixed culture, and additional fertilization.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.3
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• pp.108-118
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• 2012

To investigate the responses of yellow poplar (Liriodendron tulipifera L.) seedlings to the interactive effects of the elevated atmospheric $CO_2$ level and nitrogen addition, we measured biomass, photosynthetic pigments, photosynthesis, and the contents of nitrogen (N) and carbon (C) from the seedlings after 16 weeks of the treatments. Yellow poplar seedlings were grown under the ambient ($400{\mu}mol\;mol^{-1}$) and the elevated (560 and $720{\mu}mol\;mol^{-1}$) CO2 concentratoins with three different N addition levels (1.2, 2.4, and $3.6g\;kg^{-1}$) in the Open Top Chambers (OTC). The dry weight of the seedlings enhanced with the increased N levels under the elevated $CO_2$ concentrations and the increment of the dry weight differed among the different N levels. Photosynthetic pigment content of the yellow poplar leaves also increased with the increase of the $CO_2$ concentration levels. The effects of the N levels on the photosynthetic pigment content, however, were significantly different among the $CO_2$ levels. Photosynthetic rates were affected by the levels of $CO_2$ and N concentrations. Stomatal conductance and transpiration rates increased with increasing $CO_2$ concentration. The carboxylation efficiency of the seedlings without N addition increased under the higher $CO_2$ concentrations whereas that with N addition decreased under the elevated $CO_2$ concentrations. Nitrogen and carbon uptake in leaf, stem, and root increased with the elevated $CO_2$ concentration level and N addition. In conclusion, under the elevated $CO_2$ concentrations, physiological characteristics and carbon uptake of the yellow poplar seedling were improved and increased with N addition.

• Journal of The Korean Society of Agricultural Engineers
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• v.66 no.3
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• pp.15-23
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• 2024

Subsurface drainage improves crop productivity in poorly drained soils but may also substantially contribute impairment of surface water quality due to excess leaching losses of nutrients like Nitrate-Nitrogen (NO₃-N). This research presents preliminary findings from a 3-years tile depth and spacing study in Illinois state that includes three drain spacings implemented in 2 plots. We found that the plot with the narrower subsurface drainage (Case 1) exported more drainage water compared to the plot with the narrower subsurface drainage system (Case 2). The total drainage water from Case 1 plot showed 57% more compared to Case 2 plot. Whereas we observed that the plot with narrower drain spacing (Case 1) exported only 9% more NO₃-N leaching losses compared to the wider plot (Case 2). The average corn yield was observed higher in plot Case 1 compared to Case 2. Especially, we observed about 7% higher corn yield in plot Case 1 compared to Case 2 plot in the relatively dried year (2022). The preliminary findings for this study suggest that subsurface drainage systems can be optimized to reduce nutrient losses while improving the crop productivity.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.5
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• pp.368-373
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• 2014

Ammonia loss from urea significantly hinders efficient use of urea in agriculture. The level of nitrous oxide ($N_2O$) a long-lived greenhouse gas in atmosphere has increased mainly due to anthropogenic source, especially application of nitrogen fertilizers. There are reports in the literature showing that the addition of zeolite to N sources can improve the nitrogen use efficiency. This study was conducted to evaluate nitrous oxide ($N_2O$) and ammonia ($NH_3$) emission by mixed treatment of urea and zeolite in upland crop field. Urea fertilizer and zeolite were applied at different rates to study their effect on $N_2O$ emission during red pepper cultivation in upland soils. The $N_2O$ gas was collected by static closed chamber method and measured by gas chromatography. Ammonia concentration was analyzed by closed-dynamic air flow system method. The total $N_2O$ flux increased in proportion to the level of N application. Emission of $N_2O$ from the field increased from the plots applied with urea-zeolite mixture compared to urea alone. But urea-zeolite mixture treatment reduced about 30% of $NH_3$-N volatilization amounts. These results showed that the application of urea and zeolite mixture had a positive influence on reduction of $NH_3$ volatilization, but led to the increase in $N_2O$ emission in upland soils.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.3
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• pp.68-75
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• 2014

Soluble nitrogen produced from anaerobic digestor is able to have a strong influence on the effluent water quality of municipal wastewater treatment plants during a winter season in particular. The modeling results using the GPS-X simulation software shows that the soluble nitrogen concentration generated from the anaerobic digestor is 214.1 mg/L in the return flow and 6.2 mg/L in the inflow of the primary settler higher than those in nonexistence of the anaerobic digestor, respectively. In the case of using a separation process (flotation thickener) in order to treat the return flow from the sludge treatment system, the soluble nitrogen concentration in the effluent from the separation process and in the inflow of the primary setter could be 6.0 mg/L higher and 0.7 mg/L lower than those of nonexistence of the process, respectively. The modeling results propose the need of the equipments to be able to remove the soluble nitrogen ($NH_3-N$) produced from the digestor in the improvement projects of anaerobic digestor in municipal wastewater treatment plants.

• Journal of Animal Environmental Science
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• v.22 no.1
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• pp.35-44
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• 2016

This study was conducted to establish a database of high solid manure(HSM) in domestic. Theoretical methane potential and HSM characteristics was evaluated using breef and dairy manure (n=156). Total solids and Volatile solids of HSM increased depending on time flow, the results showed $20.4{\pm}3.2$ and $17.4{\pm}2.8%$. respectively. C/N ratio of breef HSM was higher than dairy HSM C/N ratio. In theoretical methane potential, the result of breef and dairy HSM was showed $505.2{\pm}25.3$ and $493.5{\pm}20.2$, respectively. Nitrogen content of total HSM increased depending on time flow, the result of breef and dairy nitrogen content was showed $1.9{\pm}0.3$ and $2.8{\pm}0.2$, respectively. Carbon content of total HSM showed approximately 10% reduction. The optimal time of bed replacement was indicated between 29 amd 31 days based on the optimal C/N ratio. Therefore, this study was considered that it has high utilization for livestock manure recycling and basis of relevant research.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.1
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• pp.56-62
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• 1986

Fertilization response on production and quality of flue-cured tobacco as to different level of nitrogen, phosphorus, and potassium were studied in a field experiment. The results were summarized as follows: 1. Growth and yield of flue-cured tobacco were significantly better in higher nitrogen fertilization levels, regardless of soil fertility, but the negative correlation was recognized between the quality of leaves and the amounts of nitrogen application. While, both fertilizers of phosphorous and potassium did not have should little effect on the tobacco yield and quality. 2. The optimum ratio of N, P, and K fertilizer applications were decided by the appearance of the proper yield and the best quality of tobacco leaves. The proportion of N:P:K was 2:1:4. 3. The single effect (Complete plot minus Non-fertilized plot) of N, P, and K on yield and quality of cured leaf was greatly affected by nitrogen, but the combined effect (Nutrient deficiency plot minus Non-fertilzier plot) of that were only slightly affected by P and K.