• Korean Journal of Soil Science and Fertilizer
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• v.7 no.2
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• pp.113-118
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• 1974

A study was carried out to investigate the effect of application time of fertilizer nitrogen on its rate of uptake and its distribution in rice plant. The rate of applied fertilizer was 100kg/ha, as a single application at transplanting time and four equal split applications of 25kg/ha was applied at transplanting time, 3 weeks after transplanting, 1 week before the primodial initiation stage of growth and at the flag leaf stage of growth, respectively. The ammonium sulfate was labelled with N-15, as 1% atom excess for single application and 4.4% atom excess for split applications. The results are sumarized as follows: 1. The effect of split application of nitrogen on yield was observed. The yield of brown rice of the single application at transplanting time was 3.1 ton/ha and the split application was 3.4 ton/ha. However, without nitrogen the yield was reduced to 1.9 ton/ha. 2. The number of grains per panicle and 1000 grains weight were increased as split application of nitrogen, but for the number of panicles per hill and maturing rate, the single application of nitrogen revealed favorable results. 3. The rate of uptake of applied fertilizer nitrogen showed a tendency that the efficiency of fertilizer nitrogen increased by top dressing. The rate of uptake of applied nitrogen as basal application, first top dressing, second top dressing and third top dressing was 28%, 33% 51% and 63%, respectively. 4. After shooting stage of the growth, nitrogen in straws transfered to grains. The nitrogen applied at flag leaf stage was absorbed by root and easily accumulated in grains rather than straw.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.2
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• pp.112-121
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• 1993

To study management practices suitable for the least production loss of temperate pasture under summer stress, two different cutting dates (late June and mid July) under summer stress and five different nitrogen treatment application levels (0, 100. 200, 300 and 400 kg/ha) were tried during the trial period between Oct. of 1986 and Oct. of 1989. The late June cutting showed a statistically significant increase of dry matter yield of pasture in comparison with the mid-July cutting(P<0.05). Nitrogen application also gave significant increase in dry matter yield. Botanical composition at the 4th cuttings in 1988 and 1989 was dominated by weeds to the level of 50%, Application ofnitrogen at 200 kgs per ha was found to be the best with production of grasses at 70%, legumes at 10 % and weeds at 20% in botanical composition comparison of pastures at the 4th cutting time the last year, showing a great decrease of weeds. K contents of pasture in June cuttings showed to be more than them in July cutting, and N and Na contents increased with increases of the nitrogen application level. It was concluded that treatment with June cutting and nitrogen application of 200 kg per ha was a way to keep temperate pasture from summer stress in the Cheju area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.145-149
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• 2001

This study was performed to evaluate the growth and nodulation characters of hypernodulating soy-bean mutant, SS2-2, and to know the growth and yield performance of the mutant in infertile soil. Soil fertility was adjusted by mixing the different ratios of soil components including clay, river sand, and horticultural bed, which resulted in fertile and infertile soil. Dry weight, nitrogen concentration, and leaf nitrate reductase of each plant were measured around V6 stage (47 days after planting) and around R3 stage (82 days after planting). There were significant effects of soil fertility and soybean genotype on the total dry weights including root, nodule, stem, leaf, and pod dry weight at V6 and R3 stages. Total dry weight of hypernodulating mutant, SS2-2, was clearly less than that of its wild type, Sinpaldalkong 2. However, nodule development on the roots of SS2-2 was much greater than that of Sinpaldalkong 2, regardless of soil fertility. Though SS2-2 was smaller in plant size than Sinpaldalkong 2, genotypic difference in total nitrogen content was not significant at both V6 and R3 stages because SS2-2 fixed more nitrogen biologically than its wild type in the root nodule. The SS2-2 mutant showed lower plant yield in both infertile and fertile soil. The SS2-2 contained more crude seed protein than Sinpaldalkong 2, and was characterized with reduced top and root growth.

• Journal of the Korean Society for Heat Treatment
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• v.27 no.3
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• pp.121-126
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• 2014

High-nitrogen Fe-18Mn-18Cr-N austenitic steels with higher yield strength have been recently developed and used for generator retaining rings because they have non-magnetic, high strength, high ductility, and good corrosion resistance. In the present study, a high-nitrogen Fe-18Mn-18Cr-0.61N austenitic steel was fabricated and then tensile and Charpy impact tests were conducted on them in order to investigate the effect of cold working on the mechanical properties. Although the yield and tensile strengths usually increased with cold working, the ductility and impact toughness significantly decreased after cold working. On the other hand, the high-nitrogen austenitic steel exhibited a ductile-brittle transition due to unusual brittle fracture at low temperatures despite having a face-centered cubic structure. The ductile-brittle transition temperature obtained from Charpy impact tests could be remarkably increased by $60^{\circ}C$ after 20% cold working because of the enhanced cleavage-like brittle fracture.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.323-327
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• 2002

Plant growth and the two components of respiration, growth and maintenance, were compared between low and high nitrogen applications in hydroponic culture on a high-yielding rice cultivar 'Takanari' (Oryza sativa L.). Grain yield decreased by high nitrogen application, and thus this cultivar has low adaptability to nitrogen. Growth efficiency (GE) and net assimilation rate (NAR) were lower in the high-nitrogen plot. The maintenance coefficient (m) and growth coefficient (g) of dark respiration were 0.0111 $d^{-1}$ and 0.196 in the low-nitrogen plot and 0.0166 $d^{-1}$ and 0.237 in the high-nitrogen plot, respectively. Thus, high nitrogen application increased both g and m. Calculated $R_m$ (maintenance respiration rate) was 70 and 90% of total respiration rate at heading, respectively. The significance of nitrogen adaptability and g was discussed.

• Proceedings of the Korean Society of Crop Science Conference
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• 2004.04a
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• pp.102-103
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• 2004

[ $\bigcirc$ ] In the growth simulation without changing of module with ORYZA2000, dry matter, LAI and leaf nitrogen content(FNLV) were estimated well under high nitrogen applicated condition, but overestimated under low nitrogen applicated condition. $\bigcirc$ Nitrogen stress factor on the SLA was introduced into ORYZA2000 because especially overestimated LAI under low nitrogen applicated condition was originated from SLA decrease with leaf nitrogen(FNLV) decrease. $\bigcirc$ In the growth simulation with modified SLA modified module, LAI was estimated well under even low nitrogen applicated condition, but dry matter was hardly changed compared with default. $\bigcirc$ Simulated plant nitrogen content and dry matter have no clear difference between modules, but compared with observed values, panicle weight(WSO) and rough rice yield(WRR14) were overestimated under high nitrogen applicated because of lodging, pest, disease and low nitrogen use efficiency.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.4 no.1
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• pp.81-91
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• 1968

To investigate the effects of foliage clipping time, degree, and nitrogen top-dressing after clipping on the growth and the agronomic characteristics, rice plants grown under ordinary cultural practices were clipped at the maximum tiller stage, 10 days prior to, and after that stage, respectively, with varying clipping, height, as 0, 1/3, 1/2, and 2/3 of plant height. And nitrogen was top-dressed at the rate of 0, 2, 4, 6 kg per 10 are immediately after clipping. The variety used was ＂Jinheung＂. The results obtained are outlined as follows: 1. Effect of clipping on the growth of rice plant: The subsequent growth was quite rapid during 10 days after clipping, and resulted, on the whole, in nearly complete recovery of defoliation by 20 days after clipping. a) Generally, the later the clipping time, the more growth accelerated. Rice plants clipped before the differentiation of ear primordia nearly recovered the damage, and in certain cases exceeded non-clipped plants in height. But the height of the rice plant clipped after the differentiation of ear primordia was somewhat smaller than that of non-clipped. b) Growth rate was rather rapid in the case of severe cutting, and the height of slightly clipped plants was taller than that of non-clipped plants. However, rice plants clipped to the extent of 2/3 of plant height did not fully recover the damage of defoliation compared to non-clipped plants. c) Nitrogen dressing was effective to rapid recovery of defoliation, the effect increasing with the increasing amount of application. d) Ear-heading was delayed in clipped plots, and this tendency was more apparent with later clipping time, more severe clipping, and increased amounts of nitrogen application after cutting. The range was 6 days at maximum. 2. Effect of defoliation on the yield and its components of rice plants: The yield response to clipping varied somewhat with its time, degree, and nitrogen application after cutting: yield increase of about 10% and decreasement of about 25% at maximum compared to the control plot. Grain yield of most plots was decreased. a) Clipping before the differentiation of ear primordia did not much affect the agronomic characteristics of rice plants. However, clipping after that growth stage decreased culm length, number of panicles, number of spikelets per panicle, and maturing rate of grain to some extent. Consequently this treatment resulted in decrease of about 10% in grain and straw production in spite of increase in panicle length and effective tillering rate. b) Slight, clipping decreased number of spikelets per panicle a little, and the yield of grain and straw by 4-5%, although effective tillering rate was somewhat increased. With severe clipping, panicle kngth, number of panicles, and number of spikelets per panicle decreased more, and the yield of grain and straw decreased about 10%. c) Nitrogen dressing after clipping at the rate of 2 kg per 10 are was effective in increasing grain yield. Nitrogen application over the rate of 4 kg per 10 are increased culm length, number of spikelets per panicle, and straw production, but this decreased the maturing rate, and the 1, 000-grains weight to some extent and resulted in decrease of grain yield.

• Applied Biological Chemistry
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• v.30 no.1
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• pp.9-16
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• 1987

This experiment was conducted to increase the available constituents contents of Angelica gigas Nakai and to decide the application amounts of nitrogen, phosphorus and potassium fertilizer. The effects of the amounts of their application and absorption on the contents of decursin and sugar in Angelicae gigantis Redix were studied. The decursin contents of root was decreased with increasing the application amount of nitrogen more than 10kg/10a, and increased along with the increasing application level until 20kg/10a and 15kg/10a of phosphorus and potassium, respectively. The decursin yield per 10a was increased with increasing application level until 10kg/10a, 10kg/10a and 10kg/10a of nitrogen, phosphorus and potassium, respectively. The decursin yield per l0a was decreased with increasing application level more than 20kg/10a of nitrogen. The total sugar yield per 10a was increased with increasing the application level until 15kg/10a, 10kg/10a of nitrogen and potassium respectively. But the effect of phosphorus application on the total sugar yield was not observed. The significant negative correlation was obtained between the decursin contents and the nitrogen contents of root$(r=-0.437^{\ast})$, and the significant positive correlation between the decursin contents and the contents of phosphorus$(r=0.587^{{\ast}{\ast}})$ or potassium$(r=0.467^{\ast})$ in root. But the significant correlations between the decursin contents and the their contents of shoots were not observed. It is recommended for decursin production to apply 10kg/10a, 15kg/10a and 10kg/10a of nitrogen, phosphorus and potassium, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.2
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• pp.23-30
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• 1980

Experiments were conducted to know N, P, and K top dressing effects on yield and other agronomic characters of rice plants grown in 5-year differently fertilized soils. Four levels of nitrogen, 0, 1.2, 2.4, and 3.6kg/10a, were applied 32 days before heading in 5-year non-fertilized and PK applied plots. Four levels of P_2 $O_{5}$ and K_2 O of 0, 4, 8 and 12kg/l0a were applied 40 days before heading in 5-year NK and NP applied plots, respectively. 1. Heading was delayed by seven days in 5-year non-fertilized and PK applied plots compared to NK, NP, or NPK applied plots where nitrogen was applied as basal. However, in 5-year non-fertilized and PK applied plots heading was delayed from 1 to 4 days as amounts of nitrogen top dressing increased. Phosphorus and potassium did not affect heading date of rice plants. 2. In 5-year non-fertilized plot grain yield increased as amounts of nitrogen top dressing increased up to 2.4kg/l0a due to both increased number of panicles per hill and spikelets per panicle. However, in 5-year PK applied plot amounts of nitrogen top dressing did not affect grain yield; the number of panicle per hill increased, but the percentage of ripened grains and grain weight tended to decrease as nitrogen levels increase. 3. The number of panicle/maximum tillers ratio in percentage increased markedly as amounts of nitrogen top dressing increased in 5-year non-fertilized and PK applied plots with maximum value of 130% on the basis of maximum tillers at vegetative stage. 4. Top dressing of phosphorus and potassium did not affect yield and other agronomic characters in NK and NP applied plots.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.3
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• pp.167-174
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• 2000

To investigate the effect of amount of nitrogen application on decomposition of barley straw, growth and yield of rice in paddy field of double cropping, this study was conducted to Jeonbuk series at the Honam area from 1997 to 1998. Carbon persistence of barley straw was lowered while nitrogen persistence rate was increased as increasing amount of nitrogen application and carbon -nitrogen ratio was not decreased as increasing amount of nitrogen application. Soil microflora under barley straw application was high in order of actinomycetes>cellulosedecomposer>bacteria>fungi. Nitrogen starvation under barley straw application showed at tillering stage of rice, but this was not appeared in plot of N $144kg\;ha^{-1}$ application. Plant height, culm length and ear length of rice plant by barley straw application were short, but those of N $108kg\;ha^{-1}$ application was not different from compared with none-application barley straw. Rice yield of N $108kg\;ha^{-1}$ applied barley straw was smiliar to none-application barley straw, but that of N 90. $144kg\;ha^{-1}$ was highly decreased.