• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.2
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• pp.77-80
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• 2003

This study was conducted to determine the optimum organic fertilizer rate (0, 100, 200, 300, 400, 500, 600kg/10a) of worm casting on growth response and yield of Ieol´ radish in Jeiu island. The results obtained were summarized as follows; plant height was getting bigger as organic fertilizer increased from 0 to 500kg/10a and then became smaller at 600kg/10a. But was no significance from 200 to 600kg/10a. Number of leaves, leaf width and root diameter were the same trend with plant height response. Root length was not significantly affected by organic fertilizers. SPAD reading value of leaves increased as increasing of organic fertilizers. Fresh matter yield (top+root) increased significantly 2,949∼4,561kg/10a as fertilizer rate increased from 0 to 200kg/10a, increased 5.096∼5,707kg/10a from 300 to 500kg/10a of fertilizer rate and decreased to 4,873kg/10a at 600kg/10a. Top and root weight were the same trend with fresh matter yield.

• Korean Journal of Medicinal Crop Science
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• v.13 no.3
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• pp.77-80
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• 2005

This study was conducted to determine effects of cutting date, cutting position, and node number on rooting of Rubus buergeri Miquel. Apical, medial, and basal parts of the vines emerged in 2002 were cut on June 26, August 2, and September 4, in 2002. Vine pieces with one to four nodes taken from the medial parts of the vines were also cut on July 10. The greatest rooting (69.6%) occurred in cuttings taken on August 2. Cutting taken on June 26 had the longest roots (23.1 cm). Rooting and new shoot growth markedly decreased at September 4 cutting. The greatest rooting (55.4%) occurred in cuttings taken from medial part of the vines and followed by apical parts (45.6%), and basal parts (25.4%). The other traits were not significantly affected by cutting position. Rooting percentage and percent new shoot growth were not significantly affected by node number, but root number and root dry weight per cutting, and new shoot growth increased with node number.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.432-436
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• 2002

This study was conducted in 2001 to determine the influence of seed-piece size (SPS) and number (SPN) per mini-tuber produced by hydroponics on growth and yield of potato (Solanum tuberosum L.). Treatments consisted of the combination of six SPS (3, 5, 7, 9, 11, 13g/seed-piece) and four SPN (whole tuber, and two, three, and four pieces/tuber). Percentage sprout emergence at transplanting was higher for seed pieces weighing 7 to 13 g (83.0 to 85.4%) and for three and four pieces per tuber (85.4 and 84.8%). As SPS were increased from 3 to 9 g/piece, total yields markedly increased from 2,052 to 2,924 kg/10a and seed tuber (31 to 250 g) yield from 1,589 to 2,428kg/10a with no further increase with SPS. As SPN was increased from one to three/ tuber, total yields increased from 1,918 to 2,982 kg/10a and seed tuber yields from 1,422 to 2,579 kg/10a with no further increase with SPN. Average tuber weight increased with SPS (46.3 to 71.5 g/tuber) and SPN (56.5 to 64.9 g/tuber).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.253-259
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• 2001

The purpose of this study was loused on understanding of uptake of nutrients by plants, the behaviors of nutrients in soil and the possibility of leaching loss when N fertilizer (urea) and mature compost were applied. Lysimeters (volume 0.15㎥, diameter 62cm, height 62.8cm) were installed for collecting leachate in the Jeju volcanic ash soils. Lysimeter study consisted of thirteen treatments: fellow, fellow with weeding, cropping without fertilizer and compost, three N fertilizer soil surface applications (16, 32, and 64 kg/10a), three N fertilizer and compost soil surface applications (16+800i 32+1600, and 64+3200 kg/10a), two water dissolved N fertilizer applications(16 and 32 kg/10a), and low and high plant densities. The growth of corn (preceding crop) and potatoes (succeeding crop) and leaching loss were determined during the experimental period. The amount of leachate from lysimeter was remarkably greater at bare conditions than at cropping conditions for corn and potatoes. The N content of plants (corn and potatoes) tended to increase as fertilizer rate increased. Fertilization of urea dissolved in water to soil was more efficient than surface fertilization for the growth, yield, and the N uptake N of corn and potatoes. There were no differences in dry matter yield of plants between medium and high N rates, but N, Ca, K and Mg concentrations of plants were higher at higher N rates. There were significant correlations between N uptake and each of Ca, K and Mg uptakes in corn and potatoes. Total N uptake by plants increased with increased N fertilizer and compost applications. Plane absorbed 54.9% of applied N at low N rate and 31.0 to 34.0% at high N rates. The proportion of N leaching losses was lower at low N rate and high plant density.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.5
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• pp.461-467
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• 1992

A mungbean cultivar, 'Seonhwanogdu', was seeded on April 20, May 10, June 1, June 20, July 10 and July 30 in 1988, 1989 and 1990 to determine the optimum seeding date of mungbean in Cheju province. As seeding was delayed from April 20 to June 20, the number of days from emergence to first flowering (days to flowering) decreased from 56.7 to 36.7 days, on the three year average. Days to flowering of mungbean seeded on July 10 and 30 ranged 30 to 35 days except that of the plants seeded on July 10, 1988. Days to flowering linearly decreased as the average of daily mean air temperature from emergence to the first flowering increased. The number of days from the first flowering to the first maturity (days to maturity) in mungbean seeded on April 20 to July 10 ranged 14 to 21 days and was 29 to 40 days at the July 30 seeding. The number of pods per plant, the number of seeds per pod, 1000 seed weight and yield tended to increase with delaying seeding up to June 1 and June 20, and then to decrease with further delaying seeding. This study indicates that the optimum seeding time of mungbean in Cheju province is around mid-June.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.173-178
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• 2003

To determine the optimum $\textrm{P}_2\textrm{O}_5$ rate for dry matter production of Achyranthes japonica Nakai a medicinal plant, in Jeju island, plants were grown in 2001 under ten fertilizer treatments comprising of two N (90, and 180kg/ha) and five $\textrm{P}_2\textrm{O}_5$ (0, 100, 200, 300, and 400 kg/ha) levels. Plant height leaf length and width, stem diameter, and main root length and diameter were not significantly affected by $\textrm{P}_2\textrm{O}_5$ rate while $\textrm{P}_2\textrm{O}_5$ fertilization of 100 kg/ha increased the number of branches, spikes, and roots per hill by 18,38 and 43%, respectively, compared with the unfertilized $\textrm{P}_2\textrm{O}_5$ treatment and decreased with further increases in $\textrm{P}_2\textrm{O}_5$ rate. The number of roots per hill was greatest with the application of 200kg $\textrm{P}_2\textrm{O}_5$. The highest utricle dry matter yield (2.92 t/ha) was obtained with the application of 100kg $\textrm{P}_2\textrm{O}_5$. However, as $\textrm{P}_2\textrm{O}_5$ rate increased from 0 to 100 and 200kg/ha, root dry matter yield increased from 2.36 to 3.55, and 3.80 t/ha, and then decreased to 3.14, and 2.86 t/ha at 300, and 400kg $\textrm{P}_2\textrm{O}_5$ rates, respectively. As $\textrm{P}_2\textrm{O}_5$ rate increased from 100 to 400 kg/ha, $\textrm{P}_2\textrm{O}_5$ recovery in aboveground parts decreased from 34.1 to 7.1%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.1
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• pp.60-65
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• 2017

This study was conducted to dentify the optimum plantlet type of 'Solara' potatoes (Solanum tuberosum L.) for growth in an aeroponics system. Plantlets of 'Solara' were transplanted on March 16, 2015 in a greenhouse, and growth and yield characteristics were investigated at 70 and 78 days after transplanting, respectively. Stem length was shorter in plantlet of 15-day-old stem cuttings and acclimatization of culture, and the stem length of plantlets of stem cuttings tended to increase with increasing stem cutting age. The fresh weight of plants was the highest in the plantlets of 40-day-old stem cuttings and the lowest in non-rooted stem cuttings and acclimatization of culture. The highest number of first stolons was obtained in 35-day-old stem cuttings. The number of second stolons was the highest in plantlets of 35-day-old stem cuttings, acclimatization of culture, and 30- day-old stem cuttings. The total number of tubers was higher in plantlets of 35-day-old stem cuttings and acclimatization of culture, and the number of tubers above 3 g was the highest in plantlets of 35-day-old stem cuttings. The weight of tubers above 3 g was the heaviest in plantlets of 35-day-old stem cuttings(1,947 g per 10 plants), followed by plantlets of 30-day-old stem cuttings. These results indicate that plantlets of 30 to 35-day-old stem cuttings could be the best for production of 'Solara' potato tubers in an aeroponics system.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.2
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• pp.119-124
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• 2005

This study was conducted from March 21 to July 8 in 2004 at JeJu Island to investigate the influences of split nitrogen application times on creeping bentgrass vegetation. Nitrogen rate was 20 kg/10a and it was applied from once to 5 times. The result obtained were summarized as follows; plant height was getting longer as nitrogen was split applied from once to 5 times. So it was longest at 5 times split nitrogen application, but it was no significance from 4 to 5 times. Root length, Minolta SPAD-502 chlorophyll meter reading value, leave and root weight n[e directly proportional plant height response. Degree of land cover Iud density of creeping bentgrass increased as nitrogen was split applied from once to 5 times. But degree of land cover md density of reed decreased. The number of reed species on decreased as nitrogen was split applied from once to 5 times. Then ranking of the dominant weeds were Portulaca oleracea Polygonum hydropiper and Stellaria media (at once split time nitrogen application), Portulaca oleracea, Polygonum hydropiper and Digitaria adscendens (at 2 split times nitrogen application), Digitaria adscendens and Portulaca oleracea Polygonum hydropiper, (at 3 split times nitrogen application), Portulaca oleracea, Poa annua and Polygonum hydropiper (at 4 md 5 split times nitrogen application). These results indicate that the optimum frequency of split N applications is four times for growth of creeping bentgrass in volcanic ash soils of Jeju island.

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.424-432
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• 2005

Newly introduced two lines of apios (Apios americana Medikus, red-vine and green-vine) were grown in Jeju island, to clarify their growth and production characteristics as well as to develope as a new edible crops in Korea. Both lines bloomed but did not develop to pod and seed. The red-viny line showed the habit of more early growth and maturity compared with green-viny line. Fresh tuber yields per 10a harvested in late November ranged from about 500kg to 800kg as according to the lines and cultural condition. Fresh tuber yield of red-viny line was relatively greater than that of green-viny line, mainly due to their higher tuber number per plant. Among the planting dates(April 1, April 16 and May 1) of seed tubes, highest tuber yield was obtained on May 16 planting. And the stacking cultivation culture was better than non-stacking cultivation in respect of tuber yield and disease avoidance. These results indicate that apios can produce in Jeju island, and in order to extend its cultivation to farmers it will be needed to develope some cultivars with high yields as well as labor-saving cultivation methods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.4
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• pp.359-365
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• 1994

A oat (Avena sativa) cultivar, 'Guiri 16', was seeded on Oct. 9, Oct. 24, Nov. 9, Nov. 24, Dec. 9 of 1991 and 1992 to determine usefulness of growing degree days (GDD) for predicting growth duration and the optimum seeding date of oats for grains in Cheju province. The later the seeding, the greater the number of days to emergence but the fewer the number of days to heading and maturity. As seeding was delayed, accumulated GDD from seeding to emergence generally tended to decrease but was less subjective to a constant downward tend over seeding date than the number of days. Accumulated GDD from emergence ot heading decreased with delaying seeding and accumulated GDD from heading to maturity decreased as seeding was delayed up to Nov. 24. As seeding was delayed from Oct. 9 to Dec. 9, to Dec. 9, leaf area index at heading decreased from 7.7 to 5.1 and dry matter yield at maturity from 1920 to 823 kg /10a in 1992-1993, and culm length 120 to 89cm on an average of 1991-1992 and 1992-1993. While the number of grains per panicle and test weight were not affected by seeding date in 1991-1992 and 1992-1993, the number of panicles per m$^2$ and grain yield were decreased when oats were seeded earlier or later than Nov. 9. 1000 grain weight was not affected by seeding date in 1991-1992 but greatest at Nov. 9 seeding in 1992-1993. The results indicate that optimum seeding date of oats in Cheju province would be early November. November.