• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.88-88
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• 2017

The study was conducted to analyze the growth characteristics comparison per planting density on the waxy corn early-planting culture for the paddy field in the southern province of south Korea. The cultivation period of early-planting culture for the paddy farming of the waxy corn are sown on February 15, 2016years, transplanting March 15 and harvest June 20. And it grew 126 days. The weather change according to the cultivation period of unheated plastic house early-planting culture, it was average temperature $14.6^{\circ}C$ and humidity 62.5%. And the temperature was 5.6 degrees Celsius warmer compared with the outside temperature and the humidity was 0.7 percent higher tendency. At the growth per planting density of waxy corn, culm length was average 224cm, the more it is high density culture the more was high trend. Stem diameter and ear length the more it is high density culture the more was lowed trend. The node number of $60{\times}20Cm$ was 12 nodes, fruit seting 5.7 nodes, tasseling number 94 days and silking number 96 days. In the ear characteristics per planting density, the size of ear length, seed setting length, ear width and ear weight the more planting density is high the more lowed that trend. The commodity percentage of planting density $60{\times}35Cm$ was the highest among other treatment as 69.1%. But, marketable yield was the highest planting density of $60{\times}20Cm$ as 4,543 ears/10a, and appeared in order $60{\times}25Cm$ 95%> $60{\times}30Cm$ 93%> $60{\times}35Cm$ 92%. The planting density on the waxy corn early-planting culture for the paddy farming in the southern province, the planting density analyzed to be effective planting of over 25% than normal season culture.

• Korean Journal of Weed Science
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• v.3 no.2
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• pp.156-165
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• 1983

This experiment was conducted to find out the effect of competitive duration and density of Cyperus serotinus Rottb. on rice growth and yield. In plant height of both rice and flatsedge, the compacter density of flatsedge, the higher was plant height. Rice in the 50 days competition with flatsedge had shorter culm than in other competition plots at all density. The panicle number was affected during the tillering stage. The spikelet number per panicle was influenced from 25 days to 50 days after transplanting. Grain maturity ratio and 1,000 grain-weight didn't decrease under competition before 50 days after transplanting. The competition during the tillering stage to the young panicle initiation stage decreased significantly rice yield. The rice competed with low density of flat sedge showed small decrement of yield and its components. The period reaching to maximum stem number of flatsedge become shorter as flatsedge density increased. Number of flatsedge tubers competed with rice produced was 40.1, 16.8 and 11.4 times as much in 1: 1, 1:3 and 1:5 density ratio of rice to flatsedge, respectively. Flatsedge dry matter weight and rough rice yield had the relationship of Y = 601. 95-$0.67x^{**}$.

• Journal of the Korean Society of Tobacco Science
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• v.9 no.1
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• pp.27-33
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• 1987

This study was carried out to investigate the effect of cultural practices on the nicotine and sugar contents in flue-cured tobacco(NC82), and the relationship between them. Significant reduction I sugar content and ratio of total sugar to nicotine(ratio, S/N) were observed with increased fertilizer, lower topping height, late transplanting and decreased application of male hydrazide(MH). Significant increases were observed in nicotine content with increased fertilizer and lower topping height. A positive correlation was found between total sugar content and plant density. A negative correlation was found between nicotine and total sugar contents for 8-years. An increase of 1.0% nicotine in the cured leaf would result in a 4.8% reduction in total sugar. The most desirable contents were 2.7% for nicotine and 19.0% for total sugar(S/N=7).

• Korean Journal of Plant Resources
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• v.2 no.2
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• pp.252-258
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• 1989

This study was investigated to find out the optimum planting densities of Aptum graveolns L. about growth characters, yield components and yi-eld at 9 planting densities by transplanting cultureThe results obtained are summarized as follows ;1 . Studying the correlationship, the highly negative significances we-re found between planting densities and petiole weight , planting d-ensities and plant weight , respectively .2. Plant hight was longest in spacious planting, and was short in dense3 . Petiole yield was thinkest in planting densities(50$\times$35n), and wasthin in planting densities(40$\times$25n) .4. Yield of Petiole was increased in PLanting densities(50$\times$25cn) ,quality and yield of petiole were highest by optimum plantting densi-ties (50$\times$35cn ) .

• The Plant Pathology Journal
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• v.17 no.3
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• pp.159-163
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• 2001

Influence of soil temperature [accumulated degree-day for the base temperature $5^{\circ}$($\textrm{DD}_5$)] on the development of Meloidogyne arenaria were studied in a winter grown oriental melon greenhouse in Seongju, Korea. Egg masses were first observed on roots at the accumulation of 565 $\textrm{DD}_5$(40 days after transplanting), suggesting that the nematode has completed the first generation in 40 days. Second-stage juveniles (J2) densities were lowest at 863 $\textrm{DD}_5$ in April, first increased at 1,334 $\textrm{DD}_5$ in May, peaked at 2,951 $\textrm{DD}_5$ in July, and decliner thereafter. Development of egg masses and J2 density in soil revealed that M. arenaria could develop in 7-8 generations in a year in the greenhouse. Degree-day monitoring, therefore, could aid to predict nematode development in soil and can be valuable tool a to develop root-knot nematode control strategies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.1
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• pp.55-59
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• 2005

Rice farmers can save labor and expenses by using expanded rice husk (ERH) as a seedling medium since ERH is lighter and cheaper than other commercial seedling media (CSM). This study was carried out to develop a method for rice seedling cultivation using ERH as a seedling medium. It is suggested that a mixture of $60\%$ of ERH and $40\%$ of a CSM could be used as a seedling medium; the planting densities would be 240g per tray for infant seedlings and 200 g for young seedlings; and nitrogen (N) would be applied at a rate of 1g per tray for infant seedlings prior to planting and 2g per tray for young seedlings with division. Great care should be taken to use $CO(NH_2)_2$ as an N-source fertilizer. These results would lay a foundation for the rice seedling cultivation with ERH as a medium.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.123-126
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• 2011

To investigate the forecasting of plant disease and insect for an agricultural complex and farm in environment-friendly cultivation of Rice, environment-friendly agricultural five complexs and five farms were selected in Youngam and Naju area, Jonnam, Korea. Preventation objects of plant disease and insect were leaf blast, neck blast, sheath blight, bacterial leaf blight, and hopper. Factors of sheath blight occurrence in environment-friendly agricultural complex were a fast transplanting time and a narrow planting density. Bacterial leaf blight in rice occurred severely in the area under water. Rice growth in environment-friendly agricultural complex was decreased heavy drying by hopper appearance.

• Korean Journal of Weed Science
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• v.9 no.2
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• pp.168-173
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• 1989

In the characteristics of intra-specific competition according to bulrush density, the intra-specific competition in plant height began at 5 and 15% per pot in mixed culture and bulrush monoculture, respectively. The intra-specific competition in the shoot began at 5 plants per pot in both mixed culture and bulrush monoculture. The competition in dry matter weight began at 15 plants per pot in monoculture, and at 10 plants in mixed culture. On the rice density, the plant height, and numbers of shoot and dry matter weight in rice were rapidly increased up to 2.6, and 2.5 plants per pot, respectively, And then the increments were slow, The critical intra-specific competition of bulrush with rice was 2.5 to 3 plants per pot in their traits of rice, and especially the number of shoots and dry matter weights per pot showed significant decrements. In the different transplanting time in rice, the plant heights in both rice and bulrush elongated longer in mixed culture than in monoculture. The plant height of bulrush became shorter but the height of rice longer with late transplanting. The ratio of shoot number in rice to the number in bulrush was about 1 : 3 in all plots, and shoot numbers became less by late transplanting. The dry matter weight in both species were decreased by late transplanting, and the decrements were more prominent in bulrush than in rice.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.233-233
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• 2017

Algal communities are important to maintain the aquatic ecosystems function. Algae have short life cycles, they respond quickly to environmental change and their diversity and density can indicate and the quality of their habitat. The bloom forms before the rice seedings have emerged, it may present a physical barrier that prevents the seedlings from penetrating the floodwater. Wind may also move the algal bloom, pushing the young plants beneath the surface. Another harmful action develops when the water dries up and the algae form a layer at the bottom of the field. The layer envelops the seedlings, which are not yet deeply rooted, and drag them to the surface when the water is let in again. Soil utilization pattern can be the mail facter affecting soil physico-chemical properties, especially in soil phosphorus (P). Solid content of the algae culture solution increased with the increase in the nitrogen rather the phosphors concentration. Phosphoric acid was treated with conventional treatments (100-0%, before transplanting time-tillering stage), 50-50%, 0-100%, and un-treated. The herbicide was treated on the 7 DAT (day after transplanting). Green algae samples were collected 20 DAT. Total phosphoric acid was the highest at 0.06 in 50-50% treatment in 20 DAT. The amount of green algae was about twice (9.8 mg/20ml) that of un-treated. Total number of green algae was 54 species(Green algae 35 species, Euglena 9 species, Stone wheel 10 species). Among the phosphoric acid treatment methods, the number of occurrences of green algae were the highest with 39 species in 0-100%, followed by 50-50%, 28 species, conventional treatments, 22 species, non-treatment, 18 species, respectively. Rice Yield was not significantly different by phosphoric treatment time, but slightly higher than un-treated. The maximal algal biomass was observed about 2weeks or 1 month after transplanting; the subsequent decrease of the biomass was related to the consumption by grazers and to a deficient light under the rice canopy. Maximal algal growth was observed just before tillering. To estimate the suitable method of phosphorus application in puddled-soil drill seeding of rice, available phosphorus appearance of algal water bloom, and rice yield were investigated in paddy soil of rice-barley double cropping system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.1
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• pp.8-14
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• 2013

The newly developed fertilizer is the slow-releasing fertilizer which can be used as a basal fertilizer without no additional fertilization at tillering stage. It has 30-4-6% of $N-P_2O_5-K_2O$ and was coated with mixture of LDPE (Low density polyethylene), EVA (Ethylene vinyl acetate), BDP (Bio degraded polymer), TALC and nonionic surfactant for the controlled release up to 50 days after application. Coating materials were designed to be decomposed naturally. This fertilizer can be applied directly to the seedling tray mechanically just before transplanting, resulting in significant labor saving effect. The developed slow-release fertilizer, which can replace both basal fertilization and top dressing at tillering stage by single application directly to seedling tray, showed the highest release at 14~21 days after transplanting. Considering the plant growth at different growth stages and yield, the optimal application rate of developed slow-release fertilizer was 300 g per rice nursery tray and the yield of rice at this application rate was 5.25 MT/ha. Rice quality in terms of head rice grain ratio, amylose content, whiteness, and taste value decreased as fertilization rate increased from 200 g to 500 g per nursery tray. Fertilization rate based on quantity of fertilizer ingredients (N, P, K) was reduced by 49.3% compared to the standard application rate and there was 49.2% reduction in labor input for fertilization.