• Journal of Nutrition and Health
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• v.10 no.4
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• pp.111-115
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• 1977

Vegetables and fruits purchased from several markets in Seoul from July to October in 1977 were analyzed to know the level of nitrate-and nitrite-nitrogen accumulation in relation to a public health. Radishes and chinese cabbages utilized mainly as pickled vegetables in Korea resulted in the highest concentration of nitrate-nitrogen. Some of the levels for radishes and chinese cabbages were notably high and exceeded a recommended upper limit of 300 ppm $No_{3}-N$, and thus these levels would render these samples unsafe for use. The levels in some of vegetables other than radish and chinese cabbage, e.g., spinach, lettuce, green onion, cabbage were relatively high and considered to be unsafe for use in feeding infants, where as those of green pepper, bean sprouts and parsely were very low and safe. And also the levells in fruits were very low and safe. Nitrite-nitrogen contents in all tested vegetables and fruits ranged to trace and appeared not to be accumulated in fresh vegetables and fruits. Stems and roots of radishes and chinese cabbages accumulated approximately 2 fold more nitrate-nitrogen than leaves in 5 samples of each vegetable tested.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.103-111
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• 1987

Understanding grain filling characteristics represented by grain filling duration and grain filling rate is import-ant in improving higher yielding varieties and developing better cultural methods of rice (Oryza sativa L.). Recently developed 6 Japonica and 6 Japonica/Indica varieties were grown under 3 nitrogen levels at Experimental Farm of Chungbuk National University in 1986. The range of grain filling duration of 12 varieties was 20.9-39.0 days, while grain filling rate ranged from 53.8 to 136.6 mg. panicle$^{-1}$. day$^{-1}$. Although the difference of the average grain filling duration between Japonica varieties and Japonica/Indica was less than 4 days, the average grain filling rate of Japonica/lndica varieties was greater than Japonica more than 30%. Samgangbyeo showed the shortest grain filling duration of 21.0-24.2 days and the greatest grain filling rate of 119.3-143.8 mgㆍpanicle$^{-1}$. day$^{-1}$ under 3 nitrogen levels, while Seomjinbyeo and Milyang 23 showed the quite opposite grain filling characteristics. Nitrogen levels did not show any significant effects on grain filling characteristics. Negative correlation was round between grain filling duration and grain filling rate, and significant positive correlations of grain filling rate with grains/panicle, grain weight and panicle weight indicated that grain filling rate is more important characteristics of grain filling. Pathway analysis revealed that contribution of grain filling rate to panicle weight is rather indirect through grain weight.

• Korean Journal of Agricultural Science
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• v.4 no.1
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• pp.26-33
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• 1977

We have studied the responce of nitrogen on the newly bred varieties, Yusin and Milyang #23, and the effects of defoliation at maturing stage on the rate of ripened grains under different nitrogen levels. The results obtained are summarized as follows : 1. Milyang #23 as well as Tongil was found to be highly nitrogen responsive variety and showed good grain maturing percentage. The number of grain per unit area affected the total yield under the high levels of nitrogen application. The variety, Yusin, was less responsive to nitrogen and had also less leaf area than other varieties under the high level of nitrogen application. Yusin also seemed to have low maturing percentage due to unbalanced ratio between photosynthetic area and size of storage. 2. The low internodes and leaf blade of Yusin and Milyang #15 were grown too much under high levels of nitrogen and these caused more lodging and less light penetration in pant canopy. 3. The effects of defoliation at maturing stage on yield was high under the high levels of nitrogen application, especially when defoliation was done early stage of maturing. The effects of defoliation appeared to be greates in Tongil than in Milyang #15.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.385-390
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• 2014

To evaluate the impact of nitrogen fertigation on crop growth and $NO_3$-N concentration in the soil solution, field experiment for cucumber cultivation during spring and fall season were carried out in on-farm located in Byeongcheon-myeon, Chunan-si, Chungcheonnam-do. Supplying nitrogen of 120-150 mg/L by fertigation device into soil per week reached to maximum yields of cucumber fruits. However, cucumber growth did not show any significant difference between nitrogen levels. Nitrogen supply of 400 mg/L, highest N levels, did not affect cucumber growth. Difference between green values of cucumber leaves using RGB scores were closely related with cucumber yields, and therefore, this results suggests that green values of cucumber leaves could be used as a way of determining the application rates of nitrogen for cucumber cultivation period under fertigation system.

• Journal of the Korean Society of Tobacco Science
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• v.25 no.1
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• pp.27-33
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• 2003

This study was conducted to determine the changes of nitrogen compounds in lamina and midrib during the curing process with the different curing methods, such as priming and stalk-cut curing. After KB 108 burley tobacco was cultivated by the different fetilization levels such as standard and 20% higher, only the tips and leaf were harvested. Though the contents of total alkaloid and total nitrogen were similar in lamina, midrib showed a very low contents of those components by the different curing method and fertilization levels. The content of nitrate-nitrogen in lamina increased during a middle of curing process, and then these compound was decreased during an end of curing process by stalk-cut curing method. Nitrate-nitrogen contents in the lamina by the priming curing showed a high level caused by rapid drying process during an end of curing process. That component in midrib was 5-6 times higher than that of lamina. The contents of ammonia-nitrogen in the lamina and midrib were increased during a curing process. Though those amount in tips showed a similar by a different fetilization and curing method, midrib of stalk-cut curing showed a slow increasing during a curing process.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.4
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• pp.239-244
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• 2005

This study was conducted to investigate the effect of the planting densities and nitrogen levels on the growth characteristics, dry matter yield and nutritive value of corn for silage in alpine area(altitude 800m a.s.1.) of National Livestock Research Institute from 2001 to 2002. The experiment was arranged in a split plot design with three replications. Main plots consisted of three planting densities, low(67,000 plants/ha), medium(89,000 plants/ha) and high(95,000 plants/ha). Sub plots consisted of three nitrogen levels, 150 kg/ha, 200 kg/ha, and 250 kg/ha. Tassel height of corn was increased with decreasing planting density, and nitrogen level of 200 kg/ha in all main plots. Ear height of corn was decreased with increasing planting density, and 150 kg/ha of three nitrogen levels. But there were no significant differences among treatment in tassel and ear height. Although dry matter ear ratio of whole com was increased with decreasing planting density, there were no significant differences among treatments. But there were significant differences among nitrogen levels(P<0.05). Dry matter yield of com was high with increasing planting density, but there were no significant differences among treatments. And DM yield of corn was significant difference among nitrogen levels(P<0.05). Crude protein content of corn was the highest with high planting density and low nitrogen level. NDF and ADF content of com was the highest with low planting density and nitrogen levels of 200 kg/ha in all main treatments. These results indicate that low planting density(67.000 plants/ha) and nitrogen of 150-200 kg/ha would be the optimum level fur dry matter yield and nutritive value of silage com in alpine area.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.9
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• pp.1291-1297
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• 2006

The potential of the spot urine sampling technique as an alternative to performing a total urine collection to predict the microbial nitrogen supply was evaluated in crossbred bulls. In a completely randomized design, 20 growing crossbred bulls were assigned four levels of feed intake (120, 100, 80 and 60% of voluntary dry matter intake) on diets comprised of wheat straw and concentrate mixture (50:50). After three months of experimental feeding, a metabolism trial was conducted for ten days, during which spot urine collections were performed every 6 h post feeding on days 9 and 10. The daily urinary excretion of allantoin (A) and purine derivatives (PD) decreased with the reduction in feed intake while creatinine (C) excretion remained similar in animals fed at different levels. The microbial nitrogen (MN) supply calculated from the PD excreted in total urine (35.08 to 72.08 g/d) was higher at increased levels of feed intake. PD concentration in spot urine samples had poor correlation with feed intake except at 12 h post feeding. A/C ratio and PD/C ratio in spot urine samples remained similar irrespective of sampling time and significantly (p<0.01) correlated with daily urinary PD excretion, digestible organic matter intake and dry matter (DM) intake. However, no significant differences were evident in these ratios among animals fed at levels 120, 100 and 80% of voluntary dry matter intake (VDMI) at different times post feeding. These results suggests that the spot urine sampling technique to predict the microbial protein supply is not suitable for detecting small differences in MN supply and hence, estimation of PD excreted in total urine (mmol/d) is necessary to assess precisely the MN supply in crossbred bulls.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.3
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• pp.175-181
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• 1991

The purpose of this experiment was to evaluate the effects of shade and levels of N fertilization on the dry matter yield and chemical compositions of orchardgrass grown under floor of chestnut tree. Shading conditions consist of $S_0$, (full light), $S_1$, (about 6OC4 shade) and $S_2$, (about 70% shade). And, nitrogen fertilizer was applied at 3 levels, O($N_0$), 12($N_1$), and 30($N_2$) kg per 10a, respectively. The results are may be summarized as follows: 1. Maximum total dry matter yield of $S_0$, was obtained about 1.28 ton/lOa at $N_2$, level. But, total dry matter yields of N levels in $S_1$, and $S_2$, were decreased about 42-45% compared with $S_0$. 2. The response of the dry matter yield to N fertilization were differences between shading and levels of N. Thus, the dry matter yield of $S_1$, increased almost linear up to about 30 kg/l0a level, while the dry matter yield of S, was increased slightly up to 30 kgIl0a. But. $S_2$, was increased up to 12 kg/lOa and then decreased slightly with N fertilization over the 12 kg/l0a. 3. Average increase in total dry matter yield to N fertilization were 23.85 kg, 7.97 kg and 5.08 kg DM for $S_0$, $S_1$, and $S_2$, respectively. 4. The level of 12 kg N/lOa is the limiting N level to obtain dry matter production under 60-709 shading conditions. 5. The contents of crude protein arid nitrate nitrogen were increased with shading and incremental N fertilization up to 30 kg/l0a. But, water soluble carbohydrate content was decreased greatly with high shading and high levels of N. 6. Nitrate nitrogen content indicated highly significant positive correlation with crude protein, but significant negative correlation with water soluble carbohydrate content. 7. At 30 kg N level with $S_1$, was necessary to exceed the potentially toxic nitrate nitrogen level of 0.20%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.2
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• pp.101-108
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• 2016

We investigated changes in the physiochemical quality of sailfin sandfish sauces fermented with two kojis during long-term storage at room temperature. Four fish sauces, including a control, were prepared by salt-fermentation with soybean koji (S-koji) or rice koji (R-koji) after autolysis. During storage, for 12 months, the color and levels of amino acids, total volatile base nitrogen (T-VBN) and organic acids but not moisture, salt or total nitrogen levels or pH differed markedly according to fish sauce type. The total nitrogen level was highest in S-koji, but there was no difference in the rate of increase in amino acid levels among the four fish sauces during storage. The T-VBN, of autolysis and S-koji were significantly higher than those of the control and R-koji during the entire storage period (P<0.05). The initial organic acid level did not differ among the four fish sauces, whereas it was notably higher in R-koji than in the other sauces at the end of storage. Hunter L, a and b values decreased in all fish sauces with increasing storage time. In conclusion, soybean koji may enhance the levels of nitrogen compounds as well as T-VBN in fish sauce, while rice koji reduced the formation of excess T-VBN and increased organic acid levels during storage at room temperature.

• Asian Journal of Turfgrass Science
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• v.3 no.2
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• pp.77-82
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• 1989

This experiment was carried out to determine the value of turfgrass clippings as a source of protein for animal feed. Levels of crude protein(CP) and in vitro dry matter digestibility(JVDMD) were determined for Korean lawngrass (Zoysia Japonica Steud.) under three levels of nitrogen fertilizer ( 0 , 350 and 700kg ha year and three levels of mowing interval between cuts (lO, 20, and 30 days). Sampling was done on the three-year old turffield on which nitrogen and mowing treatments were Imposed. Clippings were collected after mowing, and CP levels were calculated from a measurement of total N(CP = N >< 6.25) l)y Auto-analyser system-2 procedure and IVDMD by Maeng's method which was partly modified with Tilley and Terry's procedure. With the increased nitrogen legime the CP content of leaf clippings varied from 6.6 to 13.6% and that Of stem clippings from 4 to 10.3%. The CP levels of clippings were directly proportional to the N fertilization rate. The highest CP content was recorded in early July when it was 14.1% at 35OkgN ha -and I 18.l%kgN ha-1 with 10-wcek mowing interval. Mowing interval had little effect on the CP content in both leaf and stem clippings. The level of IVDMD in the Korean lawngrass clippings varied with mowing interval. The highest level measured was 47%, hut this varied during the growing season and occurred in the following order : early summer > summer > fall. This experiment has shown that Korean lawngrass clippings can he helpful source of protein for use in some animal feeds and that a high concentration of CP can occur depending upon N fertllizer and that of I VDM I) upon mowing practices.