• Korean Journal of Soil Science and Fertilizer
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• v.34 no.6
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• pp.407-412
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• 2001

This study was conducted to find out the effect of slow-release nitrogen fertilizer, such as latex coated urea(LCU) and Meister10(MS10) on direct seeded rice in dry soil(DS). Junghwabyeo, and early maturity rice cultivar was grown on the plots which were treated with None-nitrogen. urea. LCU and MS10 plot. Growth characteristic, yield and yield components were investigated. Nitrogen uptake-efficiency and physico-chemical properties of soil before-after experiment were analyzed. Plant height and number of tillers $m^{-2}$ in LCU and MS10 plot at early grow stages were higher than those in urea plot. Plant height and number of tillers $m^{-2}$ grown on the plot of Ms10 plot were higher than those of LCU plot. The number of seedling $m^{-2}$ were no significant differences among None-N, urea, and MS10 plot in DS. Heading date and leaf color were higher with Urea than LCU and MS10 plot. Culm length in LCU and MS10 plot were longer compared with urea plot, but panicle length was similar among with Urea, LCU and MS10 plot. Number of panicles $m^{-2}$ was greater in order of MS10 > LCU > Urea plot. Yield were greater in order of MS10 > LCU > Urea plot. Nitrogen uptake and nitrogen efficiency were greater in order of MS10 > LCU > urea plot. After the experiment, total content of nitrogen in soil was not changed at all treatments, but pH, P and Si of soil were lower than those of before experiment at all treatments.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.3
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• pp.158-163
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• 1990

This experiment was to study the effect of pure mineral nitrogen fertilizing on seasonal distribution of dry matter yield and the advisable mineral nitrogen amounts on grassland. The results were as follows: 1. With longer regrowth periods the absolute dry matter yields and the nitrogen-efficiences due to nitrogen fertilizing increased substantially, whereas the quality declined at the relatively lesser cutting frequencies. 2. The first cut at 3-cut regimes, the first and fourth cut at 4-cut regimes, and the second and last cut at 5-and 6-cut regimes showed the highest nitrogen-efficiency, respectively. 3. By the sigmaformed process of production curve the most efficient mineral N-dressing rate per ha and cut was calculated: 42-56kg N on the 3-cut areas, 39-55kg N on the 4-cut areas, 38-47kg N on the 5-cut areas and 35-48kg N/ha/cut on the &cut areas. 4. In dependence on site and kind of calculation the economical borders were reached with the following dressings of mineral N/ha/cut: 90-100kg on the 3-cut areas, 70-100kg on the 4-cut areas and 50- 90kg on the 5-and 6-cut areas.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.194-198
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• 2004

This study was conducted to identify the appropriate nitrogen fertilizer application rate for improving rice quality in tidal reclaimed area, at the Gyehwado substation of the Honam Agricultural Research Institute during 2002-2(103. The experimental fields contained 0.1% (low salinity) and 0.3-0.4% (medium salinity) Nacl in soil solution. Plant height at panicle formation stage was tall ay heavy nitrogen level and the effect of heavy nitrogen was higher in low than in high soil salinity condition. Heading date was not affected by applied nitrogen levels from 8 to 16 kg/10a in low soil salinity condition but it was one day later in 24 kg/10a nitrogen level when compared with the standard nitrogen level,20 kg/10a. In middle soil salinity condition, the heading date was one day earlier in 8 to 16 kg/10a and similar in 24 kg/10a, when compared with 20 kg/10a nitrogen level. And also it was four days later in middle than in low soil salinity condition. In low soil salinity condition, grain number $\textrm{m}^2$ increased but ripened grain ratio decreased as the nitrogen application increased and finally, milled rice yield was not different among heavy nitrogen application levels compared with 12 kg/10a. Head rice ratio was high and protein content was low in 12 kg/10a or lower nitrogen level. In middle soil salinity condition, grain number $\textrm{m}^2$ increased and ripened grain ratio was not affected as the nitrogen application increased. And finally, milled rice yield increased with increasing nitrogen application levels, Head rice ratio was high and protein content was not affected by nitrogen application levels. Therefore, on the basis of milled rice yield and rice grain quality inreclaimed land, the appropriate nitrogen application level would be 12 kg/10a in low soil salinity condition and 20 kg/10a in middle soil salinity condition.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.4
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• pp.597-599
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• 2011

This study was conducted to find out the optimum nitrogen application rate for the stable production of rape in the newly reclaimed land located at Gangwhal region of Saemangum reclaimed land in which the soil is sandy loam (Munpo series). There were five treatments of nitrogen fertilization from zero to 60% increment based on the standard fertilization of $150kg\;ha^{-1}$. The growth of rape (Sunmang) was not affected by salt content while soil salinity was increased at blossoming season of rape. Compared to yield of standard fertilization the yield and the content of oleic acid of rape were increased by 4~26% with the increasing additional nitrogen fertilizer. The results obtained from the growth and yield of rape in this study indicated that it was possible to cultivate rape in a newly reclaimed land if soil salinity was kept below $3dS\;m^{-1}$.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.4
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• pp.231-237
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• 1995

The objective of this study is to obtain the basic data for investigating the effects of organic reserves on winter survival or regrowth yield. Forage rape (Brassica napus L.) was sown by three seeding densities of 5, 15 and 25cm interval among plants on Sep. 1, 1994. Field-grown plants were sampled on the before wintering (Dec. 4) and on the wintering period (Jan. 16) to analyze the nitrogen and non-structural cahohydrate reserves. The rate of winter survival and regrowth yield were also measured in the spring of next year. The dry matter yields from the plots of 5, 15 and 25cm seeding interval were 1,270, 1.01 9 and 1,062 kg/lOa respectively, on the before wintering. The similar pattern wa5 observed in the crude protein yields affected by seeding density. On the before wintering, both of nitrogen and starch contents per plant significantly increased as the seeding density was lowered. Starch content was relatively higher than that of nitrogen in all plots. On the wintering period, the contents of nitrogen reserves were 6.5, 41.2 and 121.7 mglplant, those of starch reserves were 1.0, 5.4 and 185.1 mg/plant, respectively, in the plots of 5, 15 and 25cm seeding interval. Nitrogen reserves on the wintering period increased while starch reserves highly decreased in all plots comparing to the before wintering. 'lhe rates of winter survival were 10.2, 20.6 and 37.1%, and regrowth yields were 76, 96 and 178 kgD.M/ IOa, respectively, in the plots of 5, 15 and 25cm seeding interval. These results cleariy showed that seeding density have a close influence on the level of nitrogen and non-structurd cahohydrate reserves, and that the rate of winter survival and regrowth yield were controlled by reserves level on the wintering period.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.65-69
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• 1973

This experiment was carried out to determine the adequate amount of nitrogen for densely and lately seeded soybean, and the results obtained are as follows, 1) Various fertilization amounts of nitrogen did not effect the date of emergency, but the flowering and the maturing dates were delayed at the plots fertilized the nitrogen heavily. 2) In accordance with an increasing amount of nitrogen fertilization, the length of the stem and the internode was significantly elongated but the stem diameter was thinned down, and the latter was suggested to be the cause of lodging. 3) The 1, 000 grain weight and the number of pods per hill were decreased according to the increasing the amount of nitrogen fertilization. 4) A highly significant difference in grain yield was recognized between varieties but among treatments. However, in case of the extremly late cultivation, the grain yield of the early maturing variety (Choongbukbaeg) was increased at the plot of 6 kg nitrogen.

• Journal of Animal Science and Technology
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• v.63 no.2
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• pp.305-318
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• 2021

Alfalfa (Medicago sativa L.) is an important forage legume grown in Kansas, USA and its productivity with cool-season grasses however is unknown. The objective of this study was to determine the dry matter yield (DMY) and forage nutritive value of alfalfa-grass mixtures compared to those of alfalfa and grasses grown in monoculture with and without nitrogen fertilization. Three different alfalfa varieties were planted (reduced-lignin alfalfa, Roundup Ready, and conventional alfalfa) and two kinds of cool-season grasses (smooth brome, Bromus inermis Leyss, and tall fescue, Festuca arundinacea Schreb) were planted as a monoculture or in alfalfa-grass mixtures. Nitrogen fertilizer (urea) was applied at green-up at a rate of 56 kg/ha and after the second cutting at a rate of 56 kg/ha in 2016 and 2017, respectively. and control treatments received no nitrogen. DMY was significantly higher in monoculture alfalfa and alfalfa-grass mixtures than in grass monocultures. Between alfalfa monoculture and alfalfa-grass mixtures, no significant differences in DMY were found. For all treatments, nitrogen application significantly increased DMY compared to the control. In 2016 and 2017, the low-lignin alfalfa monoculture had the lowest acid detergent fiber (ADF) and the grass monocultures had the highest ADF. In 2016 and 2017, neutral detergent fiber (NDF) in smooth bromegrass and tall fescue was higher than in other species treatments. A low-lignin alfalfa monoculture had significantly lower NDF concentration compared to alfalfa-grass mixtures. When averaged over 2016 and 2017, relative feed value (RFV) was highest in low-lignin alfalfa and lowest in the grass monocultures. In both years, nitrogen fertilizer application did not affect nutritive values.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.72-77
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• 2008

This study was carried out to determine the response of the rice yield and grain quality by rice leaf folder (RLF, Cnaphalocrocis medinalis G.) and identify the damages caused by different transplanting dates, nitrogen amounts and chlorophyll amounts (SPAD value) of rice leaf. As the damage degree of RLF was getting severer, the ripened grain rate and 1000-grain weight were decreased and due to the increasing of chalky rice rate the rate of head rice was reduced. Therefore, the yield of head rice was decreased by 36% in heavily damaged rice plant. Among the physicochemical characteristics, protein content of rice grain was increased but amylose content was reduced, consequently, the palatability was deteriorated in heavily damaged rice by RLF. The degree of damage of RLF was getting serious as transplanting date was delayed and as the amount of nitrogen was increased. In the relationship between the SPAD value and the damage degree of RLF, as the SPAD value was increased by nitrogen fertilizing, the damage degree was also increased exponential functionally.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.153-156
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• 2011

Supplying rate of nitrogen at HV was 172.8 kg $ha^{-1}$, HV/B was 64.3 kg $ha^{-1}$ and B was 38.6 kg $ha^{-1}$. The Rice yield was 7.05 ton $ha^{-1}$ when the nitrogen supply was the largest with HV and 5.42 ton $ha^{-1}$ was produced on HV/B. The chemical characteristics of soil have lower pH and exchangeable cations(Ca and Mg) at B, HV and HV/B, rather than at CF because green manure was applied at the former step. However, the physical characteristics of the soil and the porosity showed different tendency which was that it was better at the green manure crops than CF. Nitrogen nutrient balance was showed the most balanced at CF and field of application of green manure crops were required the appropriate management if future crops would be cultivated because nitrogen nutrient could be exhausted or accumulated.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.2
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• pp.118-123
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• 2017

'Nunkeunheugchal' is a waxy black rice variety that has a large embryo. The quality of black rice depends on the anthocyanin content of the rice seed coat, which is mainly determined by cultivation environment. Factors that affect the anthocyanin content include nitrogen level, planting density, transplanting date and harvesting date. This study was carried out to investigate the optimum black rice cultivation conditions by examining the effects of different nitrogen levels and planting densities. An initial study was conducted to determine the optimum nitrogen level in which four levels of nitrogen were applied to the field (0, 4, 8 and 12 kg/10a). As the nitrogen contents were increased up to 8 kg/10a, there was a concomitant increase in rice yields. However, nitrogen levels greater than 8 kg/10a, the yield was maintained at the same level. Correlation analysis indicated that the optimum nitrogen level for maximum yield was 9.6 kg/10a. In addition, anthocyanin levels showed a trend similar to that of yield, with correlation analysis indicating that the optimum nitrogen level for maximum anthocyanin content is 10.6 kg/10a.On the basis of these results, a second study was conducted to determine the optimum combination of planting density and nitrogen level. The planting densities investigated were $30{\times}12$, $30{\times}14$, $30{\times}16$ and nitrogen levels were 7, 9 and 12 kg/10a. A high planting density ($30{\times}12cm$) was shown to produce higher numbers of tillers and yield. As calculated in the first study, a nitrogen level of 9 kg/10a shown to produce the highest anthocyanin content and yield. Collectively, the results of this study indicate that a planting density of $30{\times}12cm$ and a nitrogen level of 9 kg/10a is the optimal combination in terms of maximizing both rice yield and anthocyanin content.