• Korean Journal of Medicinal Crop Science
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• v.11 no.2
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• pp.109-114
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• 2003

To determine the optimum N rate m Jeju island for utricle and root production of Achyranthes japonica Nakai, a medicinal plant, the plants were grown at two plant densities $(50\;and\;100\;hills/m^2$, two plants per hill; mall plots) at six N application rates (0, 6, 12, 18, 24, and 30 kg/10a; split plots) in 2001. There was no significant interaction between plant density and N application rate for all measured agronomic characters. Main root length and roots per hill were 5 and 52% greater, respectively, but N content of stover was lower under lower plant density compared to higher plant density. The other characters were not affected by plant density. N application rate did not significantly affect mall stem diameter, spikes per hill, spike length, utricles per spike, mall root length and diameter, and utricle N content. As N rate increased from 0 to 30 kg/10a, SPAD values and stover N content increased linearly from 35.0 to 40.5 and 1.09 to 1.38%, respectively, and plant height, branches per hill, stover, utricle and root dry matter yields, roots per hill, and top N yield increased quadratically. Spikes per hill were increased in a cubic manner with increased N application rates. N application rate for the maximum dry matter yield of utricle and root in A. japonica was estimated to be 21 kg N/10a.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.4
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• pp.294-299
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• 1991

Eight naked barley cultivars were grown in three production systems to select proper cultivars for dual production of forage and grain and to determine production system x cultivar interactions. In the forage systems. barley was seeded on September 27 and October 17, harvested for forage on November 1. December 10 and February 12 from the September 27 planting (forage system I) and on December 10 and February 12 from the October 17 seeding(forage system II). In the grain-only system, barley was planted on November 5. In forage system I, oven-dried forage yields of eight cultivars ranged 195 to 296kg/10a and Saessalbori and Naehanssalbori yielded significantly higher than the other cultivars recording 280 and 296kg/ l0a, respectively. In forage system II, oven-dried forage yields of eight cultivars ranged 106 to 143kg/10a showing no significant difference among cultivars. Production system x cultivar interactions were significant for lodging at maturity, powdery mildew rating, 1000 kernel weight and grain yield. Leaf area index and biomass at heading, no. of spikes per $m^2$, no. of kernels per spike and test weight were not affected by the production system. Forage utilization delayed heading by 3 days and reduced culm length, spike length, lodging due to heavy rain on May 5 and lodging at maturity except for Songhagbori and Naehanssalbori. Forage utilization did not significantly affect grain yield from the September 27 planting but reduced 9% from the October 17 planting. while Saessalbori and Hyangcheonggwa 1 yielded significantly less than in the grain-only system. Songhagbori appears to be a proper cultivar for dual production of forage and grain in Cheju, considering forage and grain yields. and lodging and powdery mildew resistance.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.1
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• pp.31-37
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• 2010

Two field experiments were carried out in 2002 to evaluate effects of the sizes of tubers produced through a wick-based hydroponics on growth and yield of seed potatoes (Solanum tuberosum L. 'Dejima'). Nine sizes of seed tubers (<1, 1~3, 3~5, 5~7, 7~10, 10~20, 20~30, 30~50, and 50~80 g) were used in spring crop. In fall crop, however, tubers except for the 1 g and 50~80 g wereused with tubers 7 and 15 g produced through aeroponics. Emergence rate greatly increased as tuber size was increased up to 10~20 g and then leveled off in both croppings. The number of days from planting to emergence in spring crop was about 34 days regardless of tuber size, while that in fall crop decreased from 34 to 16 days as tuber size increased from 1~3 to 30~50 g. The number of stems per plant, stem length and diameter, and leaf size tended to increase with tuber size. As the seed tuber size increased up to 10~20 g, the number of tubers per plant, average tuber weight, total and seed tuber yields linearly increased and then slowly increased with seed tuber size. Total and seed potato yields were not significantly different between tubers produced through a wick-based hydroponics and an aeroponics when similar sized tubers were planted in the fall cropping.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.1
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• pp.23-30
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• 2002

Eveuadies 71' kenaf (Hibiscus cannabinus L.) was grown at five plant densities (1, 2, 3, 4, and 5 plants per hill; 16,000, 32,000, 48,000, 64,000 and 80,000 plants/10a) from April 13 to October 8, 2001 in Jeju island to determine influence of plant number per hill on agronomic characteristics, forage yield and quality. As plant density increased from 1 to 5 plants per hill, the plant height averaged across two harvests increased 176 to 185 cm. Compared with the plant density of two plants per hill, the plant height decreased at higher plant densities (183, 180, and 166 cm for 3, 4 and 5 plants per hill). The highest yield of fresh forage (114.6 MT/ha), dry matter (17.3 MT/ha), crude protein (2.33 MT/ha), and total digestible nutrients (TDN) (9.21 MT/ha) was obtained at 2 plants per hill. As plant density increased from 1 to 5 plants per hill, crude protein, ether extract, nitrogen free extract, and TDN contents increased from 13.1 to 15.4%, 3.0 to 3.7%, 20.1 to 23.2% and 41.1 to 45.4%, respectively, while crude fiber and crude ash contents decreased from 41.2 to 34.9% and 9.4 to 8.2%, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.1
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• pp.15-22
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• 2002

This study was conducted from April 13 to October 8, 2001 in Jeju to determine the influence of cutting height (2, 4, 6, 8 and 10 cm from the soil surface) on growth, forage yield and chemical composition of kenaf (Hibiscus cannabinus L.). As cutting height was increased from 2 to 10 cm, plant height averaged across two cuttings increased from 157.7 to 184.7 cm. This pattern held fir the number of leaves and branches per plant, stem diameter and plant weight per plant. As cutting height increased from 2 to 10 cm, fresh forage, dry matter, crude protein and TDN yields increased from 85.5 to 113.7MT/ha, from 11.97 to 15.63 MT/ha, from 1.63 to 2.72, and from 4.95 to 7.54 MT/ha, respectively. As cutting height was increased from 2 cm to 10 cm, crude protein, ether extract, nitrogen free extract, and TDN contents increased from 14.2 to 17.6%, 2.9 to 3.9%, 24.2 to 25.8% and 43.1 to 48.5%, respectively, while crude fiber and crude ash contents decreased from 35.5 to 30.4 % and 9.9 to 8.1 %, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.1
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• pp.9-14
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• 2002

Evegradies 71' kenaf (Hibiscus cannabinus L.) was grown at 160,000 plants per ha in a volcanic ash soil in Jeju island to determine the optimum frequency of split N application fer forage production. Nitrogen fertilizer was applied with 240 kg/ha, and frequencies of the split N applications were 1, 2, 3, 4 and 5 times. Plant height averaged across two harvests increased from 187 to 201cm as N was split-applied from one to three applications and then decreased to 201cm in five applications. This pattern held for the number of branches and leaves per plant stem diameter and weight of plant per plant. Fresh forage yield increased from 91.8 to 114.2 MT/ha. dry matter yield from 12.70 to 16.6 MT/ha, crude protein yield from 1.75 to 2.48MT/ha, and total digestible nutrients (TDN) yield from 5.39 to 7.63 MT/ha as N was split-applied from one to four applications, and then decreased to 106.6, 15.0, 2.32, and 7.22 MT/ha in five applications, respectively As N was split-applied from one to five applications, crude protein content increased from 13.8 to 15.4%. ether extract content from 4.1 to 5.9%, and TDN content from 42.4 to 48.1%. but crude fiber decreased from 38.2 to 37.1% and crude ash content from 11.5 to 8.6%. Nitrogen free extract content was about 19.0% regardless of cutting height.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.4
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• pp.225-232
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• 2001

In order to identify the optimum seeding rate of Jeju barnyard grass (Echinochloa crusgalli var. fiurnentacea(Roxb) Wight), 15, 20, 25, 30, 35 and 40 kilograms per a hectare were planted in April 16, 2000, respectively. The growth characterization, the yield and chemical composition were then investigated in June 28(1st cutting) and August 30(2nd cutting), 2000. According to increasing the seeding rate, plant height(155.5 to 162 cm), the yield of fresh forage(61 to 73 MT/ha), dry matter forage(11.9 to 16.9 MT/ha), crude protein(0.9 to 1.6 MT/ha), and TDN(6.1 to 9.7 MT/ha) were gradually increased until the seeding furrow, 35 kg/ha. In 40 kg/ha of seeding furrow, however, those results were decreased than that of the former seeding furrow. The contents of crude protein(7.4 to 10.4%), ether extract(3.3 to 5.2%), nitrogen free extract(46.4 to 47.8%), and TDN(52.1 to 60.4%) were also similar to those of the plant heights and the each yield excepted the seeding furrow, 40 kg/ha. Namely, the each results about the contents increased in 40kg/ha of seeding furrow. According to increasing the seeding rate, the stem diameter, number of leaves, number of withering leaves, and fresh weight were gradually decreased. The contents of crude fiber(30.3 to 27.5%) and crude ash(12.7 to 9.0%) were also decreased These results showed that the optimum seeding rate for the best of the feed production was the seeding furrow, 35 kg/ha.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.2
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• pp.129-136
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• 2004

Jeju native sorghum was grown at six spot seeding rates (1, 2, 3, 4, 5 and 6) from April 3 to september 6, 2000 in Jeju island to determine influence of number of seeds per hill in dibbling on agronomic characters, forage yield and qualities. Days to heading was increased as number of seeds per hill was increased. Plant height with three seeds per hill (206.7 cm) was the longest, while with six seeds per hill (175.2 cm) was the shortest. Fresh forage, dry matter and crude protein yield and total digestible nutrient (TDN) were the greatest at the three seeds per hill (48.1, 10.1, 0.9, 5.1 MT/ha). Crude protein, crude fat and nitrogen-tree extract (NFE) increased with the number of seeds per hill increased but crude fiber and crude ash decreased.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.139-146
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• 2004

Kenaf (Hibiscus cannabinus L.), an annual plant of the family Malvaceae, is considered to be the most promising for alternative plants with potential use as a non-wood fiber source. The objectives of this study were to select the optimum seeding date and adaptable cultivar among newly introduced kenaf cultivars (Everglades-41, Tainung-2 and Chingpi-3) in Jeju island, and to clarify the photosynthetic characteristics of those cultivars. Among the three cultivars, the fresh shoot weight per unit area of Chingpi-3 at harvest season showed highest through all seeding dates, that of while Everglades-41 was the lowest. The difference of shoot yield at harvest mainly due to seedling stand rate and plant number per unit area among the cultivars. The Chingpi-3 showed the highest shoot fresh weight in the seeding date of May 11 and decreased trend in the late seeding dates. Net photosynthesis rate was higher on Everglades-41 with entire type leaf than other two cultivars with palmate type leaf. The activity of ribulose-1,5-bisphosphate carboxylase/foxygenase (rubisco) estimated from the A-Ci curve showed highest in Chingpi-3 among three cultivars. These results suggest that Chingpi-3 might be adaptable cultivar with seeding date of around May 10 for kenaf production in Jeiu island.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.6
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• pp.434-438
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• 2001

Two late-maturing perilla cultivars for vegetables, ‘Ipdlkkae 1’ and ‘Manbaekdlkkae’, were planted on 15 May, 30 May, 15 June, 30 June, and 15 July in 2000 to determine the optimum planting date for seed production in Jeju Island. Significant interaction between cultivar and planting date was observed for number of days from planting to maturity. There were significant differences between two cultivars for days to flowering. Ipdlkkae 1 flowered two days earlier but matured one day later than Manbaekdlkkae. As planting was delayed from 15 May to 15 July, when averaged across two cultivars, days to flowering and maturity decreased from 137 to 77 days and 179 to 121 days, respectively. As planting was delayed, stem length, number of branches per plant and number of node on the main stem decreased from 150 to 81 cm, 17.0 to 7.3, and 16.9 to 10.3, respectively. Number of clusters per plant decreased 65.6 to 50.7 with delayed planting but number of capsules per cluster was not significantly affected by planting date. With delayed planting, 1,000-grain weight increased 3.2 to 3.9 g, but grain yield decreased from 1,820 to 1,338 kg/㏊. However, there was no significant difference for grain yield between 15 and 30 May plantings. The results of this study suggest that the optimum planting date for seed production of late maturing vegetable perilla may be from early May to late May in Jeju Island.