• Korean Journal of Organic Agriculture
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• v.19 no.4
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• pp.463-474
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• 2011

The objectives of this study were to establish of resource cycling agricultural system focused on farmer's organization. Case is selected as the farming corporation for the regional agriculture considering the amount of sowing by-products and livestock by-products generated. As a result, generation of fertilizer ingredient depend on feces and urine of Korean native cattle is estimated nitrogen 7.7 ton, phosphoric acid 2.9 ton, and potassium 4.9 ton. On the other hand, generation of fertilizer ingredient demand in cultivated acreage is estimated nitrogen 42.4 ton, phosphoric acid 14.3 ton, and potassium 17.0 ton. Therefore, optimum livestock numbers is estimated 1,867 cattle and it means 1,468 cattle can be raise additionally. In order to complete the resource cycling agricultural system, it should be establish nutrient management system at all of organization level and achieve improvements in regional resource supply. Both economic value of organic fertilizer and the resource cycling system linked market system is considered to develop resource cycling level.

• Journal of the Korean Society of Tobacco Science
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• v.13 no.2
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• pp.66-70
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• 1991

A field experiment was conducted to study the effects of fertilizer application rate and number of harvested leaves per plant on selected agronomic, chemical and physical characteristics of burley tobacco(Nicotiana tabacum L. cv Burley 21) in 1988, 1989 and 1990 at Chonju Experiment Station, Korea Ginseng SE Tobacco Research Institute. 175.0 or 227.5 kilogram per 10a of compound fertilizer(N-P2O5-K2O= 10-10-20) were applied as main plot, and 2 or 4 of upper leaves was topped off with 0, 2 or 4 of the lower leaves removed as sub plot. Yield, total alkaloid and total nitrogen content of cured leaves were high in the higher level of compound fertilizer plot, and increasing the level of compound fertilizer had an adverse effect on physical characteristics. Reducing the number of harvested leaves had a negative effect on yield regardless of whether the leaf number was reduced by lower topping or removing the bottom leaves, but increased the rate of higher grades leaves. Differences in total alkaloid, total nitrogen and some physical properties among number of harvested leaf per plant were smaller than expected.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.6
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• pp.505-512
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• 2006

In Korea, silicate fertilization (SF) is being practiced every four years to enhance rice production. However, the relationship between nitrogen (N) and SF in view of growth characteristics and grain yield of rice has not been examined after watermelon cropping in plastic film house. This study was carried out to identify useful critical N and Si fertilizer levels to sustain grain yield and to improve N use efficiency for rice. The watermelon-rice cropping system has maintained for three seasons in each year from 1998 to 2001 by farmer before this experiment. Experiments on N and Si fertilization levels were evaluated with Hwayoungbyeo (Oryza sativa L.) in 2002 and 2003 at Uiryeong, Korea. The goal of this experiment was to find out the optimum N and Si levels to sustain rice yield by reducing excessive N fertilizer in watermelon-rice cropping system. Nitrogen fertilization (NF) levels were three ($0,\;57,\;114kg\;ha^{-1};0,\;50,\;100%$ of conventional NF amount) and five (0, 25, 50, 75, 100%) in 2002 and 2003, respectively, and combined with three SF levels ($70,\;130,\;180mg\;kg^{-1};100,\;150,\;200%$ which were adjusted with Si fertilizer in soil) were evaluated for the improvement of N and Si fertilization level in both years. Rice yielded 3.98-5.95 and 2.84-4.02 t/ha in 2002 and 2003, respectively. Our results showed the combinations of 50% and 100% of N with 200% level of Si produced the highest grain yield in both years, respectably. The grain yield was greatly improved in plot of N25% level when compared to conventional NF (Nl00%) in 2003. In conclusion, NF amount could be reduced about 50% compared to recommended level by specific fertilization of N and Si combination levels for rice growing and grain yield after cultivation watermelon in paddy field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.40-47
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• 1987

Under the different conditions of planting density and compound fertilizer level, some agronomic and chemical characteristics of burley tobacco were investigated from 1982 to 1984. Leaf area and dry leaf weight per plant, crop growth rate, relative growth rate and net assimilation rate for 40-60 days after transplanting were higher with increasing plant spacing and fertilizer, but leaf area index was lower with increasing plant spacing. At topping stage, the leaf size was increased with increasing plant spacing and amount of fertilizer applied and the stem diameter was increased by increasing plant spacing. Leaf area, leaf weight per plant and weight per unit leaf area of harvested leaf were higher when plant spacing and fertilizer increased. It was estimated that the optimum plant spacing was 105cm x 34cm and level of com-pound fertilizer (N-P$_2$ O$\sub$5/ -K$_2$O =10-10-20) was 263kg/l0a for high yield. There were trends toward increase the contents of total alkaloid and total nitrogen with increasing plant spacing and fertilizer application. There was significant positive correlation between plant spacing and total nitrogen, and between fertilizer application and total nitrogen. The plant spacing of 105cm x 35 to 40cm and 227.5kg/l0a of fertilizer level may be profitable for farm economy and the low nitrogenous leaf.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.4
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• pp.371-378
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• 1997

The purpose of this research was to investigate the effect of P fertilization and cutting fkquency without N fertilizer on nutritive value and nitrogen fixation activity of alfalfa. A field experiment was conducted on the experimental farm of Kongju National University at Yesan from 1994 to 1996. The experimental design was a split plot design with two P levels as main plot and two cutting frequencies as the sub-plot. The results obtained are summarized as follows. Available phosphate, exchangeable Ca and Na in the soil were slightly increased with P fertilizer and basal treatment of lime. Average DM yield was 1.5 ton and 1.4 ton in second and third year. There was no significant difference within P level and cutting kquency. The first cut showed higest CP value as cutting times increased the value tend to be lowered. Crude protein content in 3 and 4 cutting regimes were from 16.3 to 16.6% 17.4 to 17.9% respectively, but no significant effect were found among the main and sub-plot. ADF and NDF in 1995 were ranged from 38.2 to 39.9, 45.1 to 58.1% respectively. ADF was 2% more higher in 1996 compared to previous year and NDF was slightly higher in 1996. There was significant difference of ADF between main plot in 1995. .P, Ca, K and Mg of 200kg P level with 3 times cutting treatment in 1995 and 1996 were 0.32 and 0.23, 0.95 and 0.84, 3.24 and 2.87, and 0.36 and 0.26. Significant difference of K and Mg between cutting frequency was observed in 1995. Nitrogen fixing activity of 400kg P fertilizer plots were higher than 200kg P level and 3 times cutting plot also showed higher acetylene reduction activity than that of 4 cutting per year. Phosphate level and cutting frequency treatment of did not significantly affect nitrogen fixation activity.

• Journal of Animal Environmental Science
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• v.19 no.2
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• pp.183-190
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• 2013

Establishment of a new concept of environmental friendly livestock manure management is required based on the facts. But now liquid fertilizer quality in korea shows a large difference among regions and the regulations are uncertain. Focusing on precedent study on main level-grading factors of liquid fertilizer quality certification, the study collected laws and standards related to liquid fertilizer of livestock manure at home and abroad and produced evaluation standards. Liquid fertilizer was divided into four factors (fertilizing value, harmfulness, stability and uniformity). According to each item, scores were awarded based on 16 details: fertilizing value (Nitrogen concentration, the whole concentration of Nitrogen, Phosphoric acid and Kalium), harmfulness (heavy metals, pathogenic microorganism and antibiotics), stability (maturity degree and odour), uniformity (EC, BOD, SS, moisture content and salt). The grade of liquid fertilizer, A (42~48), B (34~41), C (26~33) were rated using total scores.

• 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.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.1-6
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• 1993

The experiments were conducted in order to find out the response of algae as affected by fertilizer and salinity, and to determine the chemical control method of algae in 1991. The higher the nitrogen fertilizer level, the more the occurrence of a blue-green alga Oscillatoria concerning with soil flakes. An increase in phosphorus fertilizer level stimulated the growth of green alga Hydrodictyon, whereas an increase in nitrogen level caused its abrupt reduction due to the harmful effect at high concentration of nitrogen, The high level of nitrogen fertilizer also reduced the growth of Euglena, although the detrimental effect was less compared with that of Hydrodictyon. A blue-green alga Oscillatoria, a green alga Cladophora and a diatom Navicula were tolerant to salinity. Piperophos/dimethametryn was highly effective in controlling various algae such as a green alga Hydrodictyon, suspended unicellular green algae and Euglena species. A fungicide propineb and copper sulfate also effectively controlled Hydrodictyon.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.5
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• pp.311-315
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• 2001

In order to improve a soil test-based fertilization model for nitrogen, the Mitscherlich-Baule-Spillman equation modified by Bray and his coworkers was introduced and tested for its possibility of application. The coefficients $C_1$ and $C_2$ in the equation A were calculated by applying 10 pot experimental results done by the National Institute of Agricultural Sciences and Technology. Then, a regression(B) between C_1 and x, the fertilizer level was estimated. log(Ymax-Y) = logYmax-$C_1x-C_2b$ (A) where Ymax : maximum yield. Y : yield without or with a limited amount of fertilizer applied, x : application level of fertilizer, b : content of a nutrient in soil, $C_1$ and $C_2$ : coefficients of x and b, respectively. log(0.05)=$-C_1x-C_2b$ (B) Fertilizer requirement calculated by the equation B was significantly correlated with the real level of fertilizer applied for 95 percentage of the maximum yield. A more extensive and precise study on $C_1$ and $C_2$ in the equation A in expected to improve significantly the fitness of soil analysis to the fertilizer recommendation.

• Korean journal of applied entomology
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• v.9 no.1
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• pp.7-13
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• 1970

1. Kum Nam Poong which is highly susceptible to bacterial leaf blight was used as the host plant throughout this experiment. Xanthomonas oryzae 6526 was inoculated on the top of upper leaves by single needle inoculation method. After 14 days, the enlarged spots were examined in the experimental pots. Each of 3 levels of nitrogen, phosphate and potassium pots were arranged at random with three replications. 2. The amounts of nitrogen fertilizer applied and the lesion development of bacterial leaf blight were positively correlated regardless of application of phosphate and potassium fertilizers. 3. The effect of phosphate fertilizer on the lesion development was not significantly different from standard level. The lesion development was stimulated when the amount of phosphate fertilizer was increased as twice as standard level. 4. The inhibitory effect of potassium fertilizer on leaf blight was maximum by applying standard level. The stimulative effect of potassium fertilizer on the lesion development, however, was noticed. when potassium fertilizer applied was increased as twice as the standard level. 5. The heading date and spike number of rice plant were significantly correlated with the lesion development, and such phenomena were depended on the amount of nitrogen fertilizer applied regardless of the other fertilizers applied in this experiment.