• Journal of Nutrition and Health
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• v.28 no.4
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• pp.259-267
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• 1995

A study was conducted to investigate nitrogen balance and to estimate daily nitrogen requirement in 43 Korean female college students students maintaining their usual diet and activity levels. Nitrogen intake and excretion were measured in two separate peroids about one month apart, each period lasting for 3 days. Nitrogen intake was assessed by duplicate portion analysis of diet, and N excretion in faces and urine were measured during the study period. Mean daily nitrogen intake level was 129.3mg/kg B.W and the apparent digestibility of nitrogen was 76%. Mean daily urinary nitrogen excretion was 113.5mg/kg BW. 895 of total nitrogen intake. Mean daily nitrogen balance of subjects was -14.5mg/kg BW. Mean daily requirements of nitrogen for 0 balance, calculated by regression analysis of N balance and energy-adjusted N intake. were 1) 197.mg/kg B.W with the present energy intake level of the study subjects. 2) 157mg/kg B.W when energy intake is sufficient to maintain energy balance, and 30 130mg/kg B.W. when energy intake is Korean RDA level for moderate activity. When energy intake level is sufficient to meet their requirement, daily protein requirement for 0 balance is about 1.0g/kg B.W. The results of this study indicate that nitrogen intake level of young female college students is not sufficient to meet their requirements, and they should increase protein intake together with increase in energy intake.

• Journal of Nutrition and Health
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• v.21 no.1
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• pp.47-60
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• 1988

This study was performed to investigate the effect of dietary levels on protein metabolism in eight healthy Korean adult females. The 20-day metabolic study consisted of 2 day adaptation period and three 6-day experimental. Three experimental diets were low protein (LP : protein 44g), high protein(HP : protein 85g) and high animal protein (HAP : protein-84g). The apparent absorption and balance on nitrogen were significantly higher in high protein than in low protein diet. Nitrogen, absorption rate was about 75% for low protein and about 85% for high protein intake. The mean values of nitrogen balance were -1.28% for low protein and 0.78% for high protein diet. All the subjects were in negative nitrogen balance at the low protein intake while they were in positive nitrogen balance at the high protein intake. The mean daily urinary nitrogen excretion increased with increased level of protein intake. Urea nitrogen was the largest part of the urinary nitrogen. The ratio of urea nitrogen to total urinary nitrogen increased significantly for 79 to 85% as protein intake was doubled.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.5
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• pp.711-717
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• 1994

This study was conducted to obtain accurate data on intake, apparent digestibility and nitrogen balance of dietary protein which the korean take in habitually. Subjects were 8 male college students, aged from 20 to 26, and maintained their menu and life pattern as usual during a 4-week study. The same amount of diet that the subjects had consumped, and feces and urine were collected and measured to extract their nitrogen content data by Kjeldahl method. From above data, the apparent digestibility and the body nitrogen balance were estimated by determining daily protein intake and excretion. The daily protein intake measured by Jjeldahil method was 88.3$\pm$ 0.9g(1.45/kg of body weight /day) which marked 8.3% higher than that estimatd by food analysis table. The proportional of animal protein against total protein intake was 50.4$\pm$ 2.3%. Daily fecal protein loss was 14.3$\pm$0.6g and the apparent digestibility was 83.8$\pm$ 0.7%. The urinary nitrogen excretion was 10.30$\pm$0.19g. The nitrogen balance considering nitrogen excretion from feces indicated positive balance of 1.06$\pm$0.20g.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.5
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• pp.347-355
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• 2000

To determine nitrogen balance (Input-Output) of Korea that was asked by Joint Working Party of the Committee for Agriculture and the Environment Policy Committee, OECD, nitrogen input and output were separately investigated as followings: nitrogen input included the amounts of chemical fertilizer consumption, cattle manure production, and biological nitrogen fixation in the national scale, and nitrogen output summed amounts withdrawn by crop and pasture harvesting, and crop residue removal, and lost by denitrification. In 1997, nitrogen balance of Korea was $158kg\;ha^{-1}$ and $211kg\;ha^{-1}$ on including and excluding denitrification loss, respectively. N balance excluded N loss by denitrification and N withdrawal by crop residues on nitrogen output was $250kg\;ha^{-1}$, which OECD asked to except two items from N balance determination because participants were not enough their data. Nitrogen balance was increased to 1.7~2.3 times in 1997 compared with 70 and $162kg\;ha^{-1}$ in 1985, which calculated on the condition of including denitrification and excluding denitrification and removal of crop residues in nitrogen output, respectively. This increase was caused mainly by increasing livestock manure production and chemical fertilizer consumption together with agricultural land area decrease. Nitrogen input was composed with 59% of chemical fertilizer. 42% of cattle manure and 5% of others in 1997, and output was with 73% of crop production, 23% of crop residue withdrawal and 4% of pasture production. Average nitrogen balance excluded N loss by denitrification and N withdrawals by crop residues in 1995~1997 calculated by OECD was $253kg\;ha^{-1}$, which was the second highest rank in OECD participants following $262kg\;ha^{-1}$ of Netherlands. Japanese N balance that has similar farming system with us was $135kg\;ha^{-1}$.

• Korean Journal of Community Nutrition
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• v.2 no.4
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• pp.523-529
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• 1997

This study was conducted to obtain accurate data on the intake, digestibility and nitrogen balance of protein in Korean college women. Subjects were 8 female college students, aged from 21 to 23, and maintained their menu and life patterns regular during a 4- week study. The same amount of diet that the subjects had consumed, and feces and urine were collected and measured to extract their nitrogen content by Kjeldahl method. From this data, apparent digestibility and the body nitrogen balance were estimated by determing daily protein intake and excretion. The daily protein intake was 56.9$\pm$1.4g and daily fecal protein loss was 6.3$\pm$0.2g. The apparent digestibility of protein was 89.6$\pm$0.7$\%$. The daily nitrogen intake measured by Kjeldahl method was 9.43$\pm$0.2g. The urinary nitrogen excretion was 7.64$\pm$0.23g and fecal nitrogen excretion was 1.02$\pm$0.03g. The nitrogen balance indicated a positive balance of 0.45$\pm$0.18g. (Korean J Community Nutrition 2(4) : 523-529, 1997)

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.6
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• pp.831-836
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• 2006

This study compared the effects of two levels of crude protein (CP) supplementation during a close-up dry period on the productive performance, nitrogen balance, and blood profiles of Holstein cows. Eighteen cows (8 primigravid and 10 multiparous), 21 days prior to calving, were divided into four groups and fed a diet containing a low (11.5 to 12.7% CP) or high (14.1 to 15.3% CP) level of protein. Following parturition, all cows were offered the same diet. Nitrogen balance was measured 12 d to 10 d prior to the expected calving date. Whole feces and urine were collected. The higher close-up CP did not improve milk production during the early lactation period (14 w) in multiparous cows but tended to increase production by 2 kg of milk per day in primigravid cows. There were no differences in the weight of calves, the weight of the placenta, or the incidence of calving difficulty. Nitrogen intake, urine nitrogen and nitrogen retention were increased by the higher CP diet in primigravid and multiparous cows. All groups of cows showed a positive nitrogen balance. In particular, higher nitrogen retention was observed in primigravid cows fed the higher CP diet. With the exception of plasma urea nitrogen (PUN), non of the blood profiles were influenced by the CP level. The higher close-up CP increased the PUN during the period studied in primigravid and multiparous cows. These results indicate that a CP level of 14% during a close-up dry period is optimal for primigravid cows, and 12% CP level is sufficient for multiparous cows.

• Journal of Nutrition and Health
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• v.22 no.4
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• pp.223-236
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• 1989

To evaluate the differences of the levels and sources of protein intake human protein metabolism, an 26-day metabolic balance study was conducted in 10 healthy Korean adult females. In the pre-study, the subjects recorded their own diets for 3 days. The metabolic balance study consisted of 6-day adaptation period, 10-day moderate protein period(60-65g/d) and 10-day high protein period(90-95g/d). During the moderate and high protein period, 5 subjects were fed the higher animal protein meals and the other 5 subjects were fed the high plant protein meals. Body weight, nitrogen balance and blood chemistries were monitored through out the study. The urine volume were sighificantly larger in the animal protein group and, the dietary fiber and fecal weights were significantly heavier in the plant protein diet group. But no statistically significant differences were found between the two dietary groups in apparent nitrogen digestability, urinary nitrogen excretion and nitrogen balance. Body weight, serum protein, albumin and HDL-cholesterol levels were not changed, but serum total cholesterol level in the animal protein diet group was elevated significantly from 143.8mg/dl on moderate potein diet to 173.0mg/dl on high proetin diet. In conclusion, from the observation of this short-term N balance study, plant diet on the adequate level of calorie and protein intake had almost the same effect of animal protein diet for protein maintenace in adults.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.7
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• pp.1080-1084
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• 1999

Carbon (C) and nitrogen (N) balance technique was used to determine energy balance in Rhode Island Red (RIR) and White Leghorn (WL) laying hens fed maize-and broken rice (BR)- based diets. Carbon and nitrogen intake and outgo were determined for three days on ad libitum fed diets followed by 2/3 of ad libitum intake for next three days. Carbon analysis was done by using four 'U' tubes in which carbon dioxide released during bomb calorimetry was absorbed on drierite in tube 1 and 2 whereas tube 3 and 4 contained sodalime self indicating granule. Carbon in $CO_2$ was determined by an open circuit respiration system. Energy retention (E, kcal) was calculated as E = 12.386 C (g) - 4.631 N (g). By regressing metabolisable energy (ME) intake on energy balance, maintenance ME requirement of RIR was 128 whereas, that of WL hens was $144kcal/kg\;W^{0.75}/d$. Effciency of utilization of ME for maintenance from BR-based diet in RIR hens was equal but in WL hens it was 11% less than maize-based diet.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.60-65
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• 2016

The main objective of this research was to estimate the total mass of nitrogen discharged from various sources in paddy field area of South Korea in 2010 and 2013. Input and output budgets for nitrogen were estimated by mass balance approach. The mass balance approach reduces the effect of flow variations, and the large scale approach minimizes local effects, resulting in easier and faster establishment of strategy for nonpoint pollution problems. Nitrogen inputs were chemical fertilizer, compost, atmospheric deposition, biological fixation, and agricultural water, while crop uptake, denitrification, volatilization, and infiltration were nitrogen outputs. The estimated total nitrogen inputs for paddy field in South Korea were $266,211ton\;yr^{-1}$, $260,729ton\;yr^{-1}$, while those of total nitrogen outputs were $168,463ton\;yr^{-1}$, $164,994ton\;yr^{-1}$ in 2010 and 2013, respectively. Annual amounts of potential nitrogen outflow from paddy field were $97,748ton\;yr^{-1}$, $95,735ton\;yr^{-1}$ in 2010 and 2013. Also, annual rate of potential nitrogen outflow were 36.7%, 36.7% in 2010 and 2013, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.1
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• pp.1-4
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• 2005

This experiment was conducted to investigate the soil nitrogen credit of biological nitrogen fixation (BNF) and the nitrogen balance of soybean in soybean-barley cropping systems. Soybean cultivar, Shinpaldalkong2 and barley cultivar, Olbori, were used in soybean mono-cropping (SM), barley monocropping (BM), and barley­soybean double cropping system. The barley-soybean double cropping system was treated with two different levels of nitrogen fertilizers, 0 nitrogen fertilizer (BS-F0), and standard nitrogen fertilizer (BS-F1). Nitrogen and organic matter concentrations in soil of BS-F1 plot on October, 2001 were increased $4.8\%\;and\;5.9\%$, respectively, compared with those on October, 2000. The ranges of BNF rate in soybean were $69.1\~ 88.2\%$ in two years, and the rate was the highest in BS-F0 plot and the lowest in SM plot. The ranges of nitrogen harvest index (NHI) in all treatments were $83.9\~86.7\%$. The yield was 270 kg/10a in BS­F1 plot and 215 kg/10a in BS-F0 plot. However, the nitrogen balances were +0.6 kg/10a of gain of soil nitrogen in BS-F0 plot and -0.4 kg/10a of loss of soil nitrogen in BS-F1 plot. In comparisons of SM and BS-F1 plots, although the seed yields were similar in two plots, the loss of soil nitrogen was higher in SM than BS-F1 plot. Overall, our results suggest that barley-soybean double cropping system was more effective in respect to seed productivity and soil nitrogen conservation than soybean monocropping system, and the N credit to following crops by soybean cultivation was identified in soybean double cropping system.