• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.512-517
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• 2007

The limiting nutrient of eutrophication in freshwater bodies in Korea was examined and the phosphorus concentration standard for sewage treatment effluent was discussed. The weight ratio of N/P in 13 major reservoirs showed the range of 18 to 163, which implies phosphorus is more limited than nitrogen for algal growth. In the correlation analysis phosphorus showed higher correlation with chlorophyll-a concentration than with nitrogen. In the algal bioassay phosphorus spike test enhanced algal growth in all 25 samples of five reservoirs, while nitrogen was found to co-limit only in four samples. It confirms that phosphorus is the only limiting nutrient for eutrophication in Korean reservoirs. As many reservoirs are eutrophic in Korea, phosphorus control is critical for the management of water quality. The phosphorus standard of sewage treatment effluent in Korea was compared with other countries, and it can be concluded that phosphorus standard is too high to be effective in eutrophication control and a lower phosphorus standard is essential for the water quality improvement.

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.704-708
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• 2001

The effect of nutrient nitrogen on the degradation of pentachlorophenol (PCP) by Phanerochaete chrysosporium in a liquid culture was investigated. PCP disappeared at almost the same rate in both nutrient nitrogen-sufficient (NS) and -limited (NL) sttionary cultures. However, more pentachloroanisole (PCA) was accumulated in the NS culture than in the NL culture. The effect of nitrogen on the degradation of PCA was also tested in both cultures. PCA disappeared faster in the NL culture than in the NS culture, indicating that the lower accumulation of PCA during the degradation of PCP in the NL culture was due to the faster degradation of PCA in the NL culture than in the NS culture. In another experiment, PCA was added to shaking cultures rather than stationary cultures to search for any other metabolite(s). While no other metabolite but PCA was found in the NS stationary culture, 2,4,5,6-tetrachloro-2,5-cyclohexadiene-1,4-dione(TCHD) was found as the only indentifiable product in the NL shaking culture. Thus, PCP would appear to be metabolized to TCHD via PCa or directly oxidized to TCHD by lignin peroxidase. Since all the above results indicate that no innocuous metabolite was formed during the degradation of PCP by the fungus, it is quite feasible to use the fungus in the biotreatment of PCP.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.3
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• pp.370-378
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• 2017

Objective: An experiment was conducted to investigate the effects of a specific mixture of essential oils (MEO), containing thyme, clove and cinnamon EO, on rumen microbial fermentation, nutrient apparent digestibility and blood metabolites in fistulated sheep. Methods: Six sheep fitted with ruminal fistulas were used in a repeated measurement design with two 24-d periods to investigate the effect of adding MEO at 0 (control), 0.8, and 1.6 mL/d on apparent nutrient digestibility, rumen fermentation characteristics, rumen microbial population and blood chemical metabolites. Animals were fed with a 50:50 alfalfa hay:concentrate diet. Results: Ruminal pH, total volatile fatty acids (VFA) concentration, molar proportion of individual VFA, acetate: propionate ratio and methane production were not affected with MEO. Relative to the control, Small peptides plus amino acid nitrogen and large peptides nitrogen concentration in rumen fluid were not affected with MEO supplementation; while, rumen fluid ammonia nitrogen concentration at 0 and 6 h after morning feeding in sheep fed with 1.6 mL/d of MEO was lower (p<0.05) compared to the control and 0.8 mL/d of MEO. At 0 h after morning feeding, ammonia nitrogen concentration was higher (p<0.05) in sheep fed 0.8 mL/d of MEO relative to 1.6 mL/d and control diet. Ruminal protozoa and hyper ammonia producing (HAP) bacteria counts were not affected by addition of MEO in the diet. Relative to the control, no changes were observed in the red and white blood cells, hemoglobin, hematocrit, glucose, beta-hydroxybutyric acid, cholesterol, total protein, albumin, blood urea nitrogen and aspartate aminotransferase and alanine aminotransferase concentration. Apparent total tract digestibility of dry matter, crude proten, organic matter, and neutral detergent fiber were not influenced by MEO supplementation. Conclusion:The results of the present study suggested that supplementation of MEO may have limited effects on apparent nutrient digestibility, ruminal fermentation and protozoa and HAP bacteria count, blood cells and metabolites.

• Journal of Korean Society on Water Environment
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• v.28 no.1
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• pp.71-77
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• 2012

The performance and characteristics of nutrient removal in wetlands influenced by plant type. We tested a floating plant, Eichhornia crassipes, and a submerged plant, Ceratophyllum demersum, under the same environmental conditions to understand the differences in nutrient uptake by these different plant forms. The total nitrogen and phosphorus in the water decreased in the following order: Water Only < Water + Soil < Floating Plants ${\approx}$ Submerged Plants and Water Only < Water+Soil < Floating Plants < Submerged Plants. Nitrogen and phosphorous concentrations increased in both plants; however, the phosphorous concentration was greater in C. demersum than E. crassipes. The submerged plant exhibited higher phosphorus uptake per unit biomass than the floating plant, but nitrogen uptake did not differ significantly. These results suggest that the presence of soil influences nitrogen and phosphorus removal from water, and that wetland plants play an important role in the assimilation and precipitation of phosphorus. Understanding the differences in contaminant removal performance and characteristics of various plant forms can help in the selection of diverse plants for constructed wetlands to improve water quality and provide ecosystem services such as wildlife habitat and landscape enhancement.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.188-196
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• 2014

This study aimed to understand the nutrient absorption, usage and allocation of Carpinus cordata in different soil and light environments. Seasonal changes of foliar nitrogen, phosphorous, chlorophyll contents, leaf mass per area (LMA) and nutrient retranslocation rates were investigated for C. cordata saplings growing in a natural deciduous broadleaved forest and an Manchurian fir (Abies holophylla) plantation in Gwangneung, Kyunggido. The deciduous forest had lower leaf area, higher light penetration, and better soil fertility than the Manchurian fir forest. However, available soil phosphorous content in the deciduous forest was only one third of that in the Manchurian fir forest, which caused lower foliar phosphorous content and higher P retranslocation rate of C. cordata in the deciduous forest than that in the Mancurian fir forest. Soil nitrogen contents in the deciduous forest were higher than that in the Manchurian fir forest, however, no differences in foliar nitrogen content and retranslocation rate in C. cordata between the two stands were found. C. cordata in the Manchurian fir forest with high LAI throughout a year, had lower LMA, foliar nitrogen content and chlorophyll a/b, while had higher total chlorophyll content and chlorophyll/N than that in the deciduous forest. These results implied C. cordata under different environments are using different strategies for nutrient use and allocations.

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.3
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• pp.169-176
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• 2000

This experiment was carried out to investigate the effects of application levels of food waste compost andmineral nitrogen in 3 cuttings per annurn on the nutritive value and nutrient yields of orchardgrass (Dactylisglomerata L.). Annual food waste compost (FWC) and mineral nitrogen were applied at levels of 0, 10, 20,40 and 60 ton ha-', and 0, 90, 180 and 270 kg ha-', respectively. The contents of crude protein (CP, %) oforchardgrass were significantly higher at the application levels of 40 ton ha-' yr-' by FWC than those atapplication levels of 0 ton ha-' yr-' (p<0.05), the contents of neutral detergent fiber (NDF, %), acid detergentfiber (ADF, %) and hemicellulose were also higher in FWC applied plots, except for the FWC levels of 10and 60 ton ha-' yr-'. The contents of total digestible nutrient (TDN, %) and relative feed value (RFV) oforchardgrass were significantly higher at FWC levels of 10 and 60 ton ha-' yr-' than at levels of 0 ton ha"yr-'. Annual yields of CP and TDN were increased with increase the FWC levels. The highest contents ofCP of orchardgrass were obtained at 1st cut, NDF and ADF at 2nd cut. As the mineral nitrogen fertilizationwas increased, the contents of CP, NDF, ADF and hemicellulose of orchardgrass were significantly increased,but TDN and RFV were decreased. .Annual yields of CP and TDN of orchardgrass were significantlyincreased with increase the mineral nitrogen fertilization.(Key words : Food waste compost, Mineral nitrogen, Crude protein, Neutral detergent fiber, Acid detergentfiber)rgent fiber, Acid detergent fiber)

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.2
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• pp.181-188
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• 2006

The objective of this research was to determine the effects of synchronizing the rate of dietary energy and nitrogen release on: ruminal fermentation, microbial protein synthesis, blood urea nitrogen, and nutrient digestibility in beef cattle. Four, two-and-a-half year old Brahman-Thai native crossbred steers were selected for the project. Each steer was fitted with a rumen cannula and proximal duodenal cannula. The steers were then randomly assigned in a $4{\times}4$ Latin square design to receive four dietary treatments. Prior to formulation of the dietary treatments, feed ingredients were analyzed for chemical composition and a nylon bag technique was used to analyze the treatments various ingredients for degradability. The treatments were organized in four levels of a synchrony index (0.39, 0.50, 0.62 and 0.74). The results showed that dry matter digestibility trend to be increased (p<0.06), organic matter and acid detergent fiber digestibility increased linearly (p<0.05), while crude protein and neutral detergent fiber digestibility were not significantly different (p>0.05). Higher concentration and fluctuation of ruminal ammonia and blood urea were observed in the animal that received the lower synchrony index diets. As the levels of the synchrony index increased, the concentrations of ruminal ammonia nitrogen and blood urea nitrogen, at the 4 h post feeding, decreased linearly (p<0.05). Total volatile fatty acid and bacteria populations at the 4 h post feeding increased linearly (p<0.05). Microbial protein synthesis trend to be increase (p<0.08). The results of this research indicate that synchronizing the rate of degradation of dietary energy and nitrogen release improves ruminal fermentation, microbial protein synthesis and feed utilization.

• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.84-91
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• 2004

Biological nutrient removal(BNR) from wastewater was performed by adopting various process configurations. The simultaneous biological organics, phosphorus and nitrogen removal of synthetic wastewater was investigated in a sequencing batch biofilm reactor (SBBR). The other reactor was operating as a reference, without biofilm being added. The cycling time in SBR and SBBR was adjusted at 12 hours and then certainly included anaerobic and aerobic conditions. Both systems has been operated with a stable total organic carbon(TOC), nitrogen and phosphorus removal performance for over 90 days. Average removal efficiencies of TOC and total nitrogen were 83% and 95%, respectively. The nitrification rate in SBR was higher than that in SBBR. On the contrary, the denitrification rate in SBBR was higher than that in SBR. The phosphorus release was occurred in SBBR, however, not in SBR because of the inhibition effect of NO$_3$$^{[-10]}$ .

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.482-486
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• 2013

Assessment of nutrient balance in region unit is important to make a decision on nutrient management in agriculture. In this study, the nutrient demand in arable land and nutrient supply from livestock manure and chemical fertilizer were estimated from pig-concentrated areas. Three regions (H, I and J) were selected on the basis of pig numbers per unit area of arable land. In H and I regions, nitrogen amount from pig manure occupied about 50% of total livestock manure. Nutrient supply was three times higher compared to the nutrient demand in each of 3 regions. Soil available phosphate of higher pig-populated area in regional unit was higher than less populated livestock area. Therefore, livestock manure-derived regional management and monitoring of soil nutrient contents is necessary for the minimization and improvement of nutrient surplus.

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.84-90
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• 2006

This study was conducted to anticipate nitrate reduction state in tree through measurement of nitrate reductase activity (NRA) and investigate the effect of nitrogen concentrations (100, 200, 400, and 600 $mg\;L^{-1}$) on growth, the nitrogen content of various tissue, and NRA of pear (Pyrus pyrifolia cv. Niitaka) seedlings in sand culture. Nutrient solutions used in this experiment were adjusted to pH 6.5 and fixed the ratio of ammonium and nitrate to 1:3 and trickle-irrigated 3 times a day. Tree height and dry weight of various organs in seedlings were higher in low nitrogen concentration (100 and 200 $mg\;L^{-1}$) than in high nitrogen concentration (400 and 600 $mg\;L^{-1}$). The shoot growth in 600 $mg\;L^{-1}$ was extremely poor by nitrogen over supply. Increasing the nitrogen concentration, the concentration of nitrate-N in leaves and roots were insignificantly changed but that of stems increased. The accumulation of total and reduced nitrogen in all organs with increasing concentrations of nitrogen supply were increased at 30 days after treatment but those of all organs at 60 and 90 days after treatment were highest in 600 $mg\;L^{-1}$, whereas there were no significant changes among other nitrogen concentration. The in vivo (${+NO_3}^-$) NRA of all organs did not relate to nitrogen concentration but the in vivo (${-NO_3}^-$) NRA of leaves except roots increased with increasing the nitrogen concentration. Therefore, the proper nitrogen concentration to promote growth and nitrate reduction of pear tree was 200 $mg\;L^{-1}$.