• Journal of Crop Science and Biotechnology
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• v.10 no.1
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• pp.33-38
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• 2007

Nitrogen management at the panicle initiation stage(PI) should be fine-tuned for securing a concurrent high yield and high quality rice production. For calibration and testing of the recommendation models of N topdressing rates at PI for target grain yield and protein content of rice, three split-split-plot design experiments including five rice cultivars and various N rates were conducted at the experimental farm of Seoul National University, Korea from 2003 to 2005. Data from the first two years of experiments were used to calibrate models to predict grain yield and milled-rice protein content using shoot fresh weight(FW), chlorophyll meter value(SPAD), and the N topdressing rate(Npi) at PI by stepwise multiple regression. The calibrated models explained 85 and 87% of the variation in grain yield and protein content, respectively. The calibrated models were used to recommend Npi for the target protein content of 6.8%, with FW and SPAD measured for each plot in 2005. The recommended N rate treatment was characterized by an average protein content of 6.74%(similar to the target protein content), reduced the coefficient of variation in protein content to 2.5%(compared to 4.6% of the fixed rate treatment), and increased grain yield. In the recommended N rate treatments for the target protein content of 6.8%, grain yield was highly dependent on FW and SPAD at PI. In conclusion, the models for N topdressing rate recommendation at PI were successful under present experimental conditions. However, additional testing under more variable environmental conditions should be performed before universal application of such models.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.4
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• pp.217-224
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• 2001

In order to identify the growth characterization, the yield and chemical composition of Jeju barnyard grass (Echinochloa crusgalli var. fiurnentacea(Roxb) Wight) based on seeding date in Jeju region, seeding carried out the 10-day intervals from March 27 to September 30 in 2000, respectively. Plant height was 143.2 cm, showing the highest on seeding date, April 6 among that of any other seeding date. On the other hand, those of early and late seeding gradually decrease. Plant height was 119.2 an in May 16 seeding. The results of stem diameter, number of withering leaves, number of leaves and fresh weight per plant were similar to those of the plant heights. The yield of fresh, dry matter forage, crude protein and TDN found the highest on April 6 seeding, 63.5 MT/ha, 13.9 MTha, 1.1 MT/ha, and 7.6 MT/ha, respectively. In early and late seeding, the yield was gradually decreased. In seeding May 16, the yield found .38.2 MTIha in fresh forage, 6.2 MTha in dry matter forage, 0.7 MT/ha in crude protein and 3.7 MTha in TDN, respectively. According to delaying the seeding date, March 27 to May 16, the contents of crude protein (from 7.9 to 10.8%), ether extract (from 4.6 to 6.0%), nitrogen free extract (from 45.1 to 46.5%), and TDN (from 54.2 to 60.8%) were gradually increased, respectively. On the other hand, those of crude fiber (from 28.9 to 25.6%) and crud ash (from 13.5 to 11.2%) were decreased. These results showed that April 6 was the optimum seeding date with the sole object of feed production of Jeju barnyard grass under the environmental condition like as atmospheric phenomena and soil in Jeju region. (Key words : Jeju barnyard grass, Seeding date, Forage yield, Chemical composition)

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.299-306
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• 2014

Fresh edible sweet corns demand relatively short period to harvest fresh ears, which can allow farmers to make a choice sweet corns for various cropping systems. For this reason, we were to find the optimum planting date of late-planted sweet corns to sell fresh ears in the autumn linked to cropping system with winter crops, investigating yield and properties of marketable fresh ears and growth traits of sweet corns (cv. 'Godangok' and cv. 'Guseulok') depending on planting dates such as 10 July, 20 July, and 30 July in Suwon 2012 and 2013, respectively. The 20 July-planted sweet corns showed the most fresh ear yield. However, the 10 July-planted and the 30 July-planted had 32% less yield caused by consecutive rainfall from 10 July through 20 July, and 15% less yield due to low air temperature during ripening than the 20 July-planted, respectively. The 10 and 20 July-planted sweet corns had average 140g of a fresh ear weight and 15% heavier ear than the 30 July-planted. For the July-planted sweet corns, silking days after planting ($r=-0.80^{**}$), and harvesting days after silking ($r=-0.97^{**}$) and planting ($r=-0.91^{**}$) were highly negatively correlated with daily mean air temperature during the period, resulting in it takes 1,100 growing degree days (GDD) to harvest fresh ears from the July-planted sweet corns. The fresh ears of the 20 July-planted sweet corns are able to be harvested by early October. Therefore it will be a good choice for the cropping system based on winter vegetable cash crops such as temperate garlic and onion with medium or late maturity. Among three planting dates 20 July-planted sweet corns had the best field performance in every year considering fresh ear yield, ear size, and stability to grow.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.2
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• pp.177-186
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• 1971

In order to obtain an idea on the cause of beneficial effect of organic matter, compost and fresh rice straw, in paddy production, a number of previous experimental results were reviewed. The results are as follows: 1. As a soil ameriolater, compost give a beneficial effect, in well drained and somewhat permeable soils but in ill drained and none permeable paddy field the effect is not observed. 2. The effect of fresh rice straw, is expected to be positive with less than compost limitation to the soil conditions. The reason for this benefical effect of fresh rice straw to paddy yield is evidenced to be of depressing effect of early stages of paddy growth which reserves plant nutrients in soil for later use. 3. Several problems in connection with the use of fresh rice straw in rice production is also discussed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.1
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• pp.17-22
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• 2015

A total of CNU 28 hybrids were developed at the CNU Corn Breeding Lab. were evaluated to identify new cultivars in botanical characteristics, fresh yield per 10a and taste qualities. Most of these hybrids were stable in environmental stresses such as lodging, disease and insects. Stem height ranged from 115.0 to 239.3 cm, and ear height ranged from 30.7 to 107.0 cm. The ear height to stem height ratio was showed low than 50% of standard as a stable plant type to lodging. The range of ear length was 14.2 cm to 23.0 cm. Especially, CNU 13H-73 was very longest ear as a 23 cm. The fresh yield per 10a was high in purple of CNU13H-79 hybrid than control hybrid Miheuckchal, and CNU13H-73 in white hybrid was similar Yeonnong check hybrid. The 100-kernel weights in CNU13H-3 and CNU13H-9 hybrids were higher than that of the control hybrid. CNU13H-98 among hybrids had a 100-kernel weight of 20.32 g, which was heavier than that of the control hybrid Daehackchal Gold 1. The average pericarp thickness was $41.4{\mu}m$, CNU13H-46 among hybrids had a very thin pericarp as a $35.5{\mu}m$. The mean sugar content of the used hybrids was 14.95 brix%; CNU13H-73 and CNU13H-55 had higher than Mibak2 as a control hybrid.

• Korean Journal of Medicinal Crop Science
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• v.12 no.3
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• pp.231-236
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• 2004

Crop productivity would be determined by relative capacity of source and sink. The study was carried out to measure the effects of shading and flower bud pinching on growth and yield of Atractylodes japonica Koidz. Shading treatment after transplanting was done at 100%, 65, 45 or 25% level of natural light intensity but the pinching treatment was to remove all the inflorescences formed after June 10, July 10, August 10 or none. Growth and yield at early and late stages were periodically measured. At the early stage, shading mainly influenced fresh weight rather than morphological characters. At the late stage, however, severer shading decreased numbers of stems, leaves, roots, fraction and total fresh weight. 65% shading from July 1 to September 30 after skipped the emerging and early growth stages showed nearly same growth and morphological characters but more rhizome yield per unit area than non-shading. In flower bud pinching treatment, earlier pinching increased number of roots, fraction fresh weights per plant and rhizome yield per unit area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.159-162
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• 1999

This study was carried out to determine the optimum harvest date of unshelled immature peanuts and dried kernels from 60 to 120 days after flowering. Fresh pod yield of spanish-type variety, 'Shaedl-tangkong(SD)' reached a peak of 9,140kg/ ha at 70 (days after flowering(Aug. 13) while that of virginia-type variety, 'Daepoongtangkong(DP)' reached a peak of 8,820kg/ha at 90 days(Sept. 11) after flowering. SD and DP showed maximum fresh kernel yield of 6,090 and 6,470kg/ha at 90 days after flowering (Sept. 11), respectively, while dry kernel yield reached a peak of 3,300 and 3,720kg/ha at 110 days(Oct. 1), respectively. Oil content of SD and DP were the highest at 90 days and 100 days after flowering, respectively and the oil content of two varieties increased rapidly from 60 to 90 days. Tannin content of the seed hull of SD increased continuously until 110 days after flowering while that of DP maximized at 100 days. The tannin content of the two varieties increased rapidly from 60 to 100 days. Total sugar of SD and DP showed highest content at 60 days and 70 days after flowering, respectively and suger content decreased very rapidly until 80 days and after that sugar content kept nearly constant. Oil, tannin and total sugar content of spanish-type SD were higher than those of virginia-type DP.

• Journal of Ginseng Research
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• v.37 no.1
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• pp.117-123
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• 2013

Polyphenol oxidase (PPO) was purified from fresh ginseng roots using acetone precipitation, carboxymethyl (CM)-Sepharose chromatography, and phenyl-Sepharose chromatography. Two isoenzymes (PPO 1 and PPO 2) were separated using an ion-exchange column with CM-Sepharose. PPO 1 was purified up to 13.2-fold with a 22.6% yield. PPO 2 bound to CM-Sepharose, eluted with NaCl, and was purified up to 22.5-fold with a 17.4% yield. PPO 2 was further chromatographed on phenyl-Sepharose. The molecular weight of the purified PPO 2 from fresh ginseng was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and was about 40 kDa. The optimum temperature and pH were $20^{\circ}C$ and 7.0, respectively, using catechol as a substrate. Pyrogallol showed the highest substrate specificity. The effect of a PPO inhibitor showed that its activity increased slightly in the presence of a low concentration of citric acid. High concentrations of acidic compounds and sulfite agents significantly inhibited purified ginseng PPO 2.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.2
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• pp.123-128
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• 2004

This study was conducted to investigate the effects of bulb size (10, 15, 20, 25 cm) on growth and yield characteristics of edible canna in Jeju region from 20 May to 24 Nov. 2003. The results obtained were summarized as follows; Plant height grew big 78.8~129.1 cm as bulb size increased 10~25 cm. Leaf length, leaf width, number of leaves, tillers and bulb per plant and stem diameter were the same trend with plant height response. Fresh matter yield increased 29.0~91.1 MT/ha as bulb size increased from 10 to 25 cm. Fresh weight of above-ground part and bulb yield were the same trend with fresh matter yield.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.2
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• pp.115-120
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• 1990

A series of experiments were carried out for two successive years to investigate the productivity of forage turnip in mid-northern area of Korea. Fresh matter and dry matter yields of 6 foreign cultivars (Purple Top Strap Leaved, Purple Top White Globed, Seven Top, Shogoin, White Egg and Amber Globe) seeded either in early spring or in autumn after harvesting forage corn were evaluated with different seeding date and harvesting date as well as with different level of fertilization. The results obtained are summarized as follows: 1. The earlier the seeding date in spring (Mar. 29, Apr. 12, Apr. 16) was, the higher was the yield of fresh matter and dry matter as the plant growth ceased after mid June, when the temperature began to rise. 2. In spite of its high DM yield, the Japanese cultivar, Shogoin, showed poor forage quality for summer feeding due to its earlier bolting in harvesting season. 3. Of the 6 cultivars Purple Top White Globed showed highest DM yield (800 kg/ 10a) in mid area including SEOUL irrespective of planting season. 4. Although the turnips showed mostly positive yield responses to fertization, the differences were not great especially above the level of$N-P_2O_5-K_2O$: 5-3-4 kg/lOa. 5. IN TAEGWALLYONG, a northern area of Korea, the average fresh matter yield of the six cultivars tested amounted to 3,500 kg/lOa when drilled on June 30 and harvested on Aug. 30, although bulb formation during the summer was relatively poor. 6. Concluded, forage turnip is regarded to be a suitable catch-crop which has the potential to maintain and increase the total forage production in mid-northern area of Korea. The intercropping is recommendable especially for autumn planting well past the time forage corn has been harvested.