• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.1
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• pp.131-134
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• 2002

Mulberry being the only food of silkworm, Bombyx mori L., is of great economic importance to the silk industry, The success in cocoon production mainly depends on the supply of quality leaves in sufficient quantity. In mulberry, where the economic product is leaf, the uptake of nitrogen from soil is very heavy and high responses to application of nutrients have been reported. Nitrogen supports vegetative growth particularly the leaf biomass. Variation in nitrogen harvest index and other physiological and yield contributing traits were estimated in five mulberry genotypes. Considerable variation was observed for nitrogen harvest index, protein yield per plant and harvest index. The correlation studies indicated the protein yield per plant was significantly correlated with leaf yield, nitrogen content in leaf, nitrogen harvest index and harvest index. The broad sense heritability estimates revealed that harvest index showed highest heritability (88.07%) followed by nitrogen content (82.52%), protein yield (70.28%) and nitrogen harvest index (66.52%).

• Journal of the Korean Society of Tobacco Science
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• v.12 no.2
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• pp.91-101
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• 1990

A field experiment was conducted to find out the effects of field productivity, variety and nitrogen rate on the yield, quality, chemical constituents and physical properties of burley cured leaf in three field with different productivity(Degree of field productivity: A ; high, B ; medium, C : low) during successive two years(1988~89). The yield and quality were remarkably lowered when nitrogen fertilizer being applied much in low productive field. As compared with Burley 21, KB101 showed high yield, particularly the yield of KB101 in low productive field was relatively high. The effect of nitrogen rate on the yield was somewhat different according to field productivity and production year. When the nitrogen fertilizer being applied above 22.5kg/10a, the added nitrogen had no effect on the yield. Total nitrogen content of cured leaf grown in low productive field was high while total alkaloid was low, therefore total alkaloid/total nitrogen ratio was remarkably low. The lightness, red and yellow color of cured leaf grown in low productive field was remarkably low. As compared with Burley 21, the contents of total alkaloid and total nitrogen and shatter resistance index of cured leaf was somewhat low, while the filling power, lightness, red and yellow color were slightly high. Total nitrogen content of cured leaf was increased remarkably by nitrogen addition, but total alkaloid was not increased though the nitrogen fertilizer being applied above 22.5kg/10a. The filling power and shatter resistance index of cured leaf grown in high nitrogen plot, and the lightness and yellow color were low while the red color was relatively high. It comes into question that the visual quality being increased as well as increment of yield and nitrogenous compounds by nitrogen addition in high productive field. In low productive field, it is considerable that nitrogen addition for high yield should be prohibited because it causes the decrement of yield and quality, on the contrary.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.106-111
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• 1999

To investigate the effects of planting density and nitrogen level on growth and yield potential of newly bred heavy panicle japonica rice with large grain (Iksan 435 and Iksan 438) or many spikelets per panicle(HR14022-21-8-4 and HR14022-21-8-6), four heavy panicle type rices and two many panicle type rices(Dongjinbyeo and Donganbyeo) as the checks were planted under standard planting density (30$\times$15 cm) and dense planting density (15$\times$15 cm) with two nitrogen levels of standard nitrogen level(110 kg h $a^{-1}$) and heavy nitrogen level(165 kg h $a^{-1}$). Effective tiller rate decreased in dense planting or heavy nitrogen, when compared to standard nitrogen and planting, while leaf area index and to dry weight increased in dense planting or heavy nitrogen. Tiller numbers and panicle numbers were more increased by dense planting than heavy nitrogen, whereas spikelet numbers were more increased by heavy nitrogen than dense planting. Ripened grain ratio was slightly lower only in dense planting. 1,000 grain weight in brown rice was not significantly different in dense planting or heavy nitrogen. Milled rice yield was highest in heavy nitrogen with standard planting for heavy panicle type rice, while yield for many panicle type rice was highest in heavy nitrogen with dense planting, suggesting that many panicle type rice possesses higher adapt-ability for dense planting than heavy panicle type rice. Path coefficient analysis revealed that top dry weight, spikelet number and grain weight were the greatest positive contributors to yield, whereas tiller number was negative to yield.d.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.2
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• pp.93-100
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• 1995

This experiment was carried out to investigate how to effect the application of nitrogen, phosphate and potassium on the vegetation and dry matter yield in the mixed sward of orchardgrass and crabgrass (Digitaria sanguinalis [L.] Scop.). The experimental sward wa5 consisted of eight plots of non-application, P, K, PK, N. NK, NP and NPK. These plots were sown with seeds mixture of orchardgrass 17.5 kglha and crabgrass 17.5 kg/ ha on 22 April 1975 in the forage experimental field of Kangwon National University, Chunchon, Korea, and were cut four times from 6 July to 18 November 1975. The results obtained were summarized as follows: 1. In orchardgrass density measured after summering, the plot of nitrogen applied without phosphate marked only 3 1.0% of the plot of nitrogen applied with phosphate while in crabgrass density measured at that time the plot of nitrogen applied without phosphate marked as high as 112.5% of the plot of nitrogen applied with phosphate. 2. Application of phosphate and potassium improved wintering record of orchardgrass. In orchardgrass density measured after wintering, the plot of nitrogen applied without phosphate marked only 9.7% of the plot of nitrogen applied with phosphate, and the plot of NP applied without K marked 63.6% of the plot of NP applied with K. 3. In surface coverage of orchardgrass, in midsummer any plot applied with nitrogen regardless of accompanying with or not with phosphate wa5 0%, but in autumn the plot of nitrogen applied with phosphate was 56-58% and the plot of nitrogen applied without phosphate was 5%. While after wintering the plot of nitrogen applied with phosphate was 28-37% though the plot of nitrogen applied without phosphate was only 0.3-0.6%; the application of phosphate improved summering and wintering record of orchardgrass. 4. Application of phosphate demonstrated remarkable effect on increasing dry matter yield in orchardgrass. In year total yield of orchardgrass, the plot of nitrogen applied without phosphate marked as low as 11.3% of the plot of nitrogen applied with phosphate, but in crabgrass the plot of nitrogen applied without phosphate was almost equal to the plot of nitrogen applied with phosphate showing 97.5% of this plot. 5. Application of potassium was not effective on increasing dry matter yield of orchardgrass but its application was effective on increasing dry matter yield of crabgrass. In dry matter yield of orchardgrass significant difference was not found between NP plot and NPK plot, but in dry matter yield of crabgrass NPK plot recorded significantly higher yield compared with NP plot (p<0.05). 6. In botanical composition of the plot of nitrogen applied with phosphate, crabgrass recorded 46.5-50.5% in early summer (July) but in midsummer (August) it dominated the plot recording 85.6-91.2%. 7. In botanical composition based on the year total yield, in the plot of nitrogen applied with phosphate orchardgrass marked 21.7-26.2% and crabgrass recorded 73.8-78.370, but in the plot of nitrogen applied without phosphate orchardgrass marked only 3.5% being overwhelmingly dominated by crabgrass which recorded 96.5%. 8. Application of nitrogen not accompanied with phosphate strengthened competitive power of the crabgrass unilaterally, making orchardgrass be oppressed fatally by the crabgrass.

• Environmental and Resource Economics Review
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• v.9 no.4
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• pp.641-661
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• 2000

The study examines the relation between yield insurance and nitrogen fertilizer in Korea. Since the yield insurance has never been introduced in Korea, the simulation method developed by Babcock & Hennessy is used to see the effect. From the simulation, we obtained the following results: (1) When a farmer is assumed to have a risk-neutral utility function, the yield insurance reduces nitrogen fertilizer by 19.74% (2) When a farmer is assumed to have a risk-averse utility function, the yield insurance reduces nitrogen fertilizer by 24.53%.

• Korean Journal of Plant Resources
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• v.5 no.1
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• pp.57-68
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• 1992

The effects of various kind and amount of nitrogen fertilizers on the plant grorth. physiological , yield and extracts. ligustilide, butylidene phthalide contents of curdsdrug "Tou-ki" (AnTelica acutiloba Kitagawa) were investigated in 1989. Five plots variouskind of nitrogen fertilizers. Namely, no nitrogen, urea. ammonium nitrate, ammoniumchloride and control plot of ammonium sulfate. The other, by providing five plotsdifferent composed ratio of nitrogenous fertilizers. containing no nitrogen (No. o) .0.5-fold nitrogen (No s), control plot of 1.0-fold nitrogen(Nl.o). 1.5-fold nitrogen(Nl s)and 2.0-fold nitrogen Na. o), but nitogen was used the ammonium sulfate. The results showedthat the crude drug "Tou-ki" can ammonium chloride be produced in good yield, displayingboth good plant growth and remarkable physiologically-active conditions, and it can beproduced such that the extracts is maximized. Additionally, using methods of gaschromatography (GC) , it was established that ligustilide and butylidene phthalide, majorcomponents in the crude drug was recovered in a good yield from the fully grown plants.The other, the plant growth, the physiologically-active, the weight of whole plant, theyield of extracts and ligustilide, butylidene phthalide were seen to be best at the plotof 2.0-fold nitrogen and according to the increase or decrease of nitrogen decreasedgradually. Therefore. about 2 fold of standard quantity seems to be the most suitablequantity of nitrogen for "Tou-ki" cultivation .uot;Tou-ki" cultivation .ion .

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.3
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• pp.213-219
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• 2013

A field study was conducted to understand nitrogen use efficiency of high yielding Japonica rice varieties under three levels of nitrogen fertilizer (90, 150 and 210 kg N $ha^{-1}$) in Iksan, Korea. Two high yielding rice varieties, Boramchan and Deuraechan, and an control variety, Dongjin2, were grown in fine silty paddy. Nitrogen use efficiencies (NUE) were 83.3, 56.3, and 41.2 in 90, 150, and 210 kg N $ha^{-1}$ fertilizer level, respectively. Total nitrogen uptake varied significantly among nitrogen levels and varieties. Variety Dongjin2 showed the highest nitrogen uptake efficiency (NUpE), while Boramchan and Deuraechan showed higher nitrogen utilization efficiency (NUtE). However, Nitrogen harvest index (NHI) was higher in Boramchan (0.58) than Deuraechan (0.57) and Dongjin2 (0.53). Rough rice yield showed linear relationship with total nitrogen uptake ($R^2$=0.72) within the range of nitrogen treatments. Boramchan produced significantly higher rough rice yield (8546 kg $ha^{-1}$) which mainly due to higher number of panicles per $m^2$ compared to Deuraechan (7714 kg $ha^{-1}$). Deuraechan showed higher number of spikelets per panicle, but showed lower yield due to lower number of panicle per $m^2$. Rice varieties showed different nitrogen uptake ability and NUE at different nitrogen level. Plant breeders and agronomist should take advantage of the significant variations and relationships among grain yield, NUpE, and NUE.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.2
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• pp.69-75
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• 1994

This experiment was canied out to study the effect of cutting frequencies (3, 4 and 5 cuts per year) and mineral nitrogen fertilization on dry matter yields, in order to estimate optimum level of fertilizing mineral nitrogen in orchardgrass(Dacry1is glomerafa L.). The results are as follows: 1. Dry matter yields were the highest in the 1st cut at 3 cutting frequency and in the 2nd cut at 4 and 5 cutting frequencies, and they shared 49.7, 37.0 and 37.0% of annual dry matter yield respectively. 2. When only phosphorus and potassium were applied, annual dry matter yields were between 9.4 and 11.5 tons per ha and the highest yield was observed at 3 cutting frequency. 3. Dry matter yield in relation to fertilization of mineral nitrogen was highly increased when more nitrogen was applied as 360 kg per ha compared to 240 kg per ha at 3 cutting frequency. At 4 and 5 cutting frequencies, increases in dry matter yield, to large extent, were showed at 120 and 150 kg of nitrogen per ha(30 kg Nlcutlha) compared to no application of nitrogen. The efficiencies of mineral nitrogen fertilization (kg DM/kg N) were 28.0, 22.7 and 20.6 kg dry matter yields per nitrogen(kg) respectively). 4. At 4 and 5 cutting frequencies, dry matter yields were reduced when 360 kg and 300 kg of mineral nitrogen per ha(90 kg and 60 kg Nlcutlha) were applied respectively. 5. Particularly at 4 and 5 cutting frequencies of this study, maximum marginal yields reached at 129.9 kg and 148.0 kg of fertilizing mineral nitrogen per ha, and economical borden of mineral nitrogen fertilization were between 222.4 and 250.0 kg and between 244.8 and 276.8 kg respectively. At the same cutting frequencies, the highest dry matter yields were obtained at 365.4 and 433.8 kg of fertilizing mineral nitrogen respectively.

• KSBB Journal
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• v.13 no.5
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• pp.626-630
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• 1998

Ammonium limitation did not promote ply(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) production of Azotobacter vinelandii UWD. In acid phase, ammonium limitation during utilization of propionic acid and butyric acid led to 35% decrease in product yield. In glucose phase, both biomass yield and polymer yield decreased about 22% under ammonium limitation. However, in nitrogen-fixing culture glucose was consumed 25% faster and the final PHBV wt% decreased slightly. Under nitrogen limitation a portion of the carbon sources was used fro nitrogen fixation rather than biomass and polymer formation, resulting in a decrease in biomass yield and polymer yield.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.313-316
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• 2000

The effects of initial sugar concentration and the various nitrogen sources on the fermentation characteristics of Thraustochytrium aureum were investigated. The sugar conversion ratios decrease with increase in the initial sugar concentration regardless of the kinds of nitrogen sources. The specific growth rate, the biomass yield, and the DHA yield also decreased but approached constant values higher than the concentration of 30g/L. The sugar conversion ratios and the specific growth rate showed the highest values in case of using the yeast extract as nitrogen source. It was difficult to conclude that the variation of nitrogen source had some effects on the biomass yield. However, the initial sugar concentration had a rather effects on the biomass yield for the sugar concentration of 40 g/L showed 0.27. The nitrogen source that showed the greatest yield of DHA was sodium glutamate.