• Korean Journal of Soil Science and Fertilizer
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• v.1 no.1
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• pp.61-71
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• 1968

1. In pot exreriments, the leaf blades of rice plants grown on Akiochi soil were weakened and the leaves dropped noticeably. This phenomenon could be prevented with application of silicate materials such as potassium silicate, Wallastonite and silicate slag (normally used silicate fertilizer in Korea). 2. Grain yield was increased by application of all the silicate materials. The effect of wollastonite was not lower than the effect of silicate slag. 3. Basal application of wollastonite gives a higher effect on the grain yield than top dressing. With higher wollastonite application, the nitrogen effect on the grain yield increases. This increase in nitrogen effect becomes more pronounced when the nitrogen level is higher. 4. Silica content in the plant waas increased by application of silicate materials to the soil. The increase in silica content in the plant was most noticeable with wollastonite. Basal application of wollastonite proved to be more effective than top dressing. Iron and nitrogen content in the plant decreased by application of the silicate materials. 5. The application of the silicate materials to Akiochi soil increases the resistance of rice to leaf blast, neck blast and Helminthosporium leaf spot. Among the silicate materials, wollastonite was most effective. 6. Damage by leaf blast increased proportionally with the nitrogen level, but decreased clearly with increase in wollastonite level. This phenomon was most pronounced for late transplanting time. 7. Damage by Helminthosporium leaf spot was also proportionally reduced by wollastonite application.

• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.629-636
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• 2019

This study was conducted to investigate the growth characteristics and yield of whole green rice grains during the ripening period. These were investigated using Hopumbyeo and Unkwangbyeo at two transplanting times and with two kinds of nitrogen fertilization. The transplanting times were May 30 and June 20, respectively, using 30-day seedling culture and transplanting conducted with 3 - 4 plants per hill in planting space of $15cm{\times}30cm$. During nitrogen fertilization, 9 kg and 18 kg was used, respectively. The harvest of the green whole rice grains was carried out on the 15th, 20th, 25th, 30th, and 40th day after the heading date. The clum length was greater with later planting and with application of more nitrogen. The rice yield was higher with nitrogen fertilization of 18 kg/10 a when transplanted on May 30 for Hupumbyeo, and for Unkwangbyeo, was higher at 9 kg/10 a nitrogen fertilization when transplanted on May 30. The protein content of Hopumbyeo was higher when the nitrogen fertilizer was 18 kg/10 a, and that of Unkwangbyeo was lower than that when transplanting on June 20. The greenness was not related to the nitrogen fertilization level when transplanted on May 20 but for later transplanting, the greenness was higher when the nitrogen application was increased, and the greenness was the greatest about 30 days after the heading date.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.128-133
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• 2000

This study was carried out to investigate the effect of forms and levels of nitrogen fertilizer on plant growth and essential oil production of Agastache rugosa. Calcium nitrate had more influenced on length and width of leaves and lateral branch length than did urea. When nitrogen fertilizer level was increased from 12 kgN/I0a to 24kgN/I0a, plant growth was stimulated and dry matter of leaf and inflorescence were increased. Top dry matter of plant with calcium nitrate treatment (38.4 g) was heavier than that of urea treatment (32.8 g). Interactions among accession and nitrogen form and nitrogen rate were not significantly different for top dry matter. The forms and rate of nitrogen fertilizer did not affect estragole content. The estragole contents was higher in leaf (91.8%) than that of inflorescence (81.3%). While the essential oil content was not affected by different nitrogen forms, nitrogen level affected the essential oil contents positively by increasing dry matter. Essential oil yield was not affected by accession or nitrogen form, but by nitrogen rate. With increasing N application from 12kgN/I0a to 24 kgN/I0a, essential oil yield was increased by 95.8 %.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.1
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• pp.70-75
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• 2010

In Korea, standard N application level was amended from 110 to 90kg per ha for high quality rice production in 2005. So far, N application method, however, has not been considered for yield and quality based on changed standard N application level. Therefore, this experiment was conducted to find out more efficient N application method for improving rice quality or labor saving under the amended standard N application level with several varieties at three site (Suwon, Iksan, and Milyang) for two years from 2005 to 2006. Top dressing of N at 15 days before heading compared to the standard (25 days before heading) showed improved rice qualities such as 1000 grain weight and head rice ratio without changing rice yield and protein content of brown rice. In addition, there were no significant differences in yield and quality between different N split application of 70-0-30% and 50-30-20%, indicating that the former would be useful for labor saving without yield decrease and quality deterioration.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.2
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• pp.214-219
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• 2008

An experiment was conducted to evaluate the effects of nitrogen (N) level on the dry matter (DM) yield, N concentration and oxalate content of some tropical grasses, namely Rhodesgrass (Chloris gayana), Guineagrass (Panicum maximum) and Sudangrass (Sorghum vulgare). Three levels of N as urea were applied (Standard- 260, $Standard{\times}2$- 540 and$Standard{\times}4$- 1,060 kg N/ha for Rhodesgrass; Standard- 380, $Standard{\times}2$- 770 and $Standard{\times}4$- 1,570 kg N/ha for Guineagrass and Sudangrass) in a completely randomized design and grasses were harvested twice at approximately two-month intervals. Dry matter yield tended to be higher with increased rate of N fertilizer in all species, while further additional N ($Standard{\times}2$ or $Standard{\times}4$) did not significantly (p>0.05) further increase DM yield, when compared with the Standard level of N fertilizer application. There was also a trend towards higher N concentration in plants as N fertilization increased in all species and it was increased significantly in Rhodesgrass and Sudangrass (p<0.05 or p<0.01, respectively). Further additional N ($Standard{\times}2$ or $Standard{\times}4$) application showed no significant (p>0.05) differences on oxalate content in plant tissue within species, when compared with the Standard level of N. The Rhodesgrass contained 0.11, 0.13 and 0.15% soluble oxalate and 0.23, 0.25 and 0.27% total oxalate with Standard, $Standard{\times}2$ and $Standard{\times}4$ level of N application, respectively. The Guineagrass contained 0.54, 0.50 and 0.42% soluble oxalate and 1.60, 1.56 and 1.45% total oxalate with Standard, $Standard{\times}2$ and $Standard{\times}4$ level of N application, respectively. The Sudangrass contained 0.06, 0.15 and 0.12% soluble oxalate and 0.22, 0.22 and 0.21% total oxalate with Standard, $Standard{\times}2$ and $Standard{\times}4$ level of N application, respectively The results from this study suggest that these grasses do not use further addition of N fertilizer ($Standard{\times}2$ or $Standard{\times}4$) to form high content of oxalate salts, when compared with the Standard level of N. In addition, the levels of oxalate present with these grasses are quite low as far as toxicity to animals is concerned.

• Asian Journal of Turfgrass Science
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• v.1 no.1
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• pp.18-29
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• 1987

This study was carried out to examine the effect of nitrogen application and clipping interval on the characteristics of several turf components of korean lawngrass for the basic data of lawn management. It was treated by Split plot design with three replications. The main plots were nitrogen levels with 0, 350, and 700kgN / ha, and the sub plots were clipping intervals with 10, 20, and 30 days The results obtained are summarized as follows ; 1. Increasing the rate of nitrogen fertilizer and frequent clipping increased tiller number of korean lawngrass and the maximum number of tillers obtained in October were recorded from 700kgN application and clipping treatment of 10 days interval. Meanwhile, treatment of 350kgN with 10 days clipping interval increased tillers much more than those of 700kgN with 20 and 30 days clipping intervals. 2. The average number of green leaves occurred during the growth period maximized by applying 700 kgN and clipping 10 days interval. 3. Increasing tiller numbers significantly decreased tops DM weight per tiller by clippng plants at interval of 10 and 20 days, irrespective of nitrogen applied, and with nil N, at the interval of 30 days. By applying 700kgN however, tops DM weight per tiller increased as the number of tillers increased consistently. 4. The highest tops DM weight was achieved from late August to early September by applying 350 and 700kgN. 5. During the growth period, nitrogen application increased unders(stolon+root) DM weight, and, at the same level of nitrogen applied, the increase in stolon DM weight enhanced by lengthening the clipping interval to 30 days. 6. Nitrogen efficiency to green leaves, stolon nodes and DM weight of root with high nitrogen was achieved as clipping interval was shortened.

• Food Science and Preservation
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• v.5 no.2
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• pp.123-126
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• 1998

This study was carried out investigate to optimum levels of nitrogen and phosphate fertilizer to get a higher yield and a quality of an onion(Allium Cepa L.) from 1993 to 1994. Three fertilizer levels were applied with 120, 240 and 360kg/ha of nitrogen and 100, 200 and 300kg/ha of P2O5 during the onion growing season. After harvesting the onion, it was storaged at given deposit. The growth and yield of the onion were better at the fertilizer levels of both 240 and 360kg/ha of nitrogen and of both 200 and 300kg/ha of P2O5 than at the level of 120kg/ha in nitrogen and 100kg/ha of P2O5. The content of total nitrogen and P2O5 in plant was decreased with reduced application levels of nitrogen and phosphate fertilizer. The rotting rate was higher at the levels of both 360kg/ha in nitrogen and 300kg/ha in P2O5 than the other treatment during the storage period. The sprouting rate tended to be high at 240kg/ha of nitrogen and 100kg/ha of P2O5.

• 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 Practical Agriculture & Fisheries Research
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• v.20 no.1
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• pp.175-185
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• 2018

This study was conducted to evaluate the physiological and ecological characters of rice cultivars suitable for low fertilized condition. 5 rice cultivars(Jinmibyeo, Sobibyeo, Hwayeongbyeo, Nagdongbyeo and Junambyeo) were cultivated for selection under 3 different nitrogen application levels, and 1 cultivars were selected. The results obtained are summarized as follows ; High yielded rice cultivars under low N application level were Junambyeo, Jinheng and Sobibyeo. Also these cultivars were yielded highly under conventional level(11kg/10a). Milled rice yield under conventional level(11kg/10a) was positively correlated with them under low N levels. Milled rice yield was most affected by no. of grain/m². Rice cultivars that were high crop growth rate(CGR) before heading stage were Junambyeo, Sobibyeo and Nagdongbyeo. Grain filling rate was increased mostly until 20 days after heading, and decreased after this stage. Nitrogen use efficiency was higher under low N level(5.5kg/10a) than conventional level(11kg/10a). Especially, Junambyeo was most low in Apparent recovery of applied N(AR) under low N application level, but most high in Agronomic N use efficiency(ANUE). This characteristics of Junambyeo will to be useful for selection of variety suitable for growing under low fertilized condition.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.5
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• pp.280-289
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• 2003

The purpose of this study was to establish a model for recommendable application level of nitrogen fertilizer based on soil testing for summer chinese cabbage in highland. A field experiment was carried out with various nitrogen application levels in sand loamy soil with and without poultry manure compost. The application level of N in poultry manure compost plot was found to be $291kg\;ha^{-1}$ for maximum yield of chinese cabbage, and it was 87% of the required N application level, $335kg\;ha^{-1}$, for maximum yield of chinese cabbage in nonmanure plot. In the treatment of poultry manure, approximately $174kg\;ha^{-1}$ of N was required to obtain the same yield of chinese cabbage as the maximum yield obtained in the treatments without poultry manure application. Therefore, with poultry manure application, N application level can be reduced by 40%. Using these results, a new equation for N recommendation for chinese cabbage in highland soil was proposed. With the average organic matter content of $33g\;kg^{-1}$ in highland field, the application levels of N for chinese cabbage were in the range of $215-129kg\;ha^{-1}$, which means that 32.8-59.7% of current application amount of N fertilizer can be reduced.