• Korean journal of applied entomology
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• v.4
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• pp.33-38
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• 1965

1. This survey was conducted to make a basis for the cause of severe epidemic and disease control to the losses due to bacterial leaf blight of rice in Chun-Nam rice paddy field areas in the first part of October in 1965. The severe epidemic areas were included Taijun-Myun, Tamyang-Eup, riverside in Youngsanpo and seaside in the suburbs of Mokpo. 2. A drought in the period of rice transplanting and flooding due to a heavy rain in July were resulted reasonable weather conditions that the disease occurred more early and severe epidemic. 3. In Tamyang area, frist outbreak of the disease was on the middle part of July in the paddy flooded after heavy rainfall of the first fart of July. It is recognized to farmers that the disease is known as a now serious one. 4. The more date of transplanting is followed, the more serious damage is happened and especially, in the paddy field flooded, too. 5. Flooded areas showed more serious epidemic. 6. Varietal difference to the disease was surely noticed, and Kumnampoong and Chunbonwuk were susceptible, whereas Norin 6 was resistant. 7. Damage was occurred more in plant paddy area than tile slopping paddy area. 8. Fallow paddy field was more serious than the field using double cropping a year. 9. Moist and semimoist paddy field were more serious damage, while light damage in dry paddy field. 10. Near part of flood gate for drainage of submerge paddy was more serious damage than inside part of the field. 11. Soft type is often seen in the mode of the disease occurrences. 12. The most farmers insisted that dropping water is caused to promote disease dissemination when disease occurred.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.325-330
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• 2004

This study was carried out to determine adequate planting date, to compare the growth characteristics between early and late maturing cultivars, and to provide the data for the cultivation techniques of soybean [Glycine max (L.) Merr.] in double cropping system with winter crops on paddy field in Korea. Cultivars were planted on 26 May, 16 June, and 7 July with a planting density of $70cm(row\;widtb)\;{\times}\;10cm$ (planting spacing). Seed yield of soybean planted on June 16 and July 7 was approximately $37\%\;and\;53\%$, respectively, less than that of conventional planting date of May 26 in Pungsan-namulkong, and planted on June 16 and July 7 was about $30\%\;and\;37\%$, respectively, less then that of conventional planting date of May 26 in Hanamkong. The number of pods and seeds per plant decreased as planting date delayed. Seed weight increased in Pungsan-namulkong but decreased in Hannamkong as planting date delayed. The flowering date was late in delayed planting plots, but it was shorted for days from emergence to flowering and from emergence to maturity. The plant height of Hannamkong was greater than Pungsan-namulkong from the emergence to flowering stages, but in contrast, it was greater in Pungsan-namulkong than Hannamkong after flowering stage (50d after emergence) when it planted on May 26. There were no significant differences between two soybean cultivars at planting dates of June 16 and July 7. Leaf number, leaf area, and dry matter were also reduced by late planting, and Both of them were shown in high reduction at the later planting. There was a high significant difference at the flowering $(r\;=\;0.87^{**})$ and pod formation $(r\;=\;0.91^{**})$ stages between leaf dry matter and seed yield. Crop growth rate (CGR) was greater at $R2\~R3$ growth stages compared to $R3\~R4\;or\;R4\~R5$ growth stages in two soybean cultivars and the greatest CGR was obtained at planting date of May 26 in two soybean cultivars except for R4-R5 growth stage in Pungsan-namulkong. There was a highly significant positive difference between the seed yield and the leaf area index (LAI) across R3 to R4 and R2 to R3 stages. The photosynthetic rate $(P_N)$ of the uppermost leaf position had no significant difference among planting dates and between two soybean cultivars. However, $P_N$ of the $7^{th}$ leaf position increased as the planting date delayed.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.305-305
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• 2017

Seoritae with green cotyledons refers to Korean native black beans harvested when the frost falls because the maturity is late. It is one of the beans preferred by consumers because of its softness and high sugar content. Because of late maturity, if the agricultural work is delayed by weather or agricultural schedule in green cotyledon black soybean (Seoritae), it affects seriously harvest and yield of soybeans. The aim of this study was to investigate the marginal seeding period on June 30, July 10 and July 20 in Cheongju and Jecheon area in Korea to produce stable soybean yield. The yields of green cotyledon black soybean as seeding date in Cheongju area are as follows: Seolitae (Yeoncheon), Seoltae (Goesan) and Seoritae (Gogseong), which increased by 23%, 56%, 23% and 40%, respectively, compare to July 10th to June 30th. As soybean sowing is delayed, the quality of soybean seeds has decreased due to the increase of immature seeds and fungal damaged seeds. The contents of anthocyanin in Cheongju area a functional substance of soybeans, was high on July 20 for Heukcheong, on June 30 for Seolitae (Yeoncheon), on July 10 for Seoritae (Goesan). The yields of Heukcheong and Seolitae (Yeoncheon) in Jecheon area were increased by 5% and 17%, respectively, compare to July 10th to June 30th, while Seolite (Goesan) and Seolite (Gogseong) were high in yields on June 30th. Similarly in Cheongju area, as the sowing period is delayed, the number of immature and mold damaged seeds in Jecheon area increased. The contents of anthocyanin in Jecheon area was high on July 10 for Heukcheong, on June 30 for Seolitae (Yeoncheon) and Seolitae (Goesan). From the above results, Sowing marginal date of green cotyledon black soybeans (Seolitae) in Cheongju area increased 30% in sowing on July 10 and increased 2% in sowing on July 20 compared to June 30. And Sowing marginal date of green cotyledon black soybeans (Seolitae) in Jecheon area increased 2% in July 10 compared to June 30, and the yield decreased rapidly on July 20. We have identified the seeding time limit of green cotyledon black bean in Chungbuk province. It will be possible to provide a variety of crop selection after double cropping of farmers. And by knowing the yield and seed quality of soybean according to sowing date, farmers will observe appropriate sowing period of soybeans for high quality. From the viewpoint of consumers, functional substances of Seoritae will meet the desire for health.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.123-129
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• 1982

To determine the optimum harvesting date with good grain yield and quality, six different harvesting dates were tested from 25 to 50 days heading with five days intervals, using two varieties of Baekdong, naked barley and Olmil, wheat. The dates when grain yield, 1,000 grain weight and grain/whole spike weight ratio were reached to the highest were 35 and 40 days after heading for Baekdong and Olmil, respectively. Various grain qualities such as unhulled grain, plumpness, protein content and whiteness of grain were also very good at that times. One day earlier harvesting before the optimum dates resulted in yield decreases by 3.9% for Baekdong and 4.4% for Olmil. And it might be delayed for each 5 days with Combine harvesting.

• Korean Journal of Organic Agriculture
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• v.17 no.3
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• pp.381-391
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• 2009

Crop production can be secured by the cycle of green manure crops as an alternative of the chemical fertilizer. Recently, rapeseed (Brassica napus L.) has been cultivated in the south part of Korea for the production of biodiesel. In this research, we focused on recycling rapeseed residue, which is produced after harvesting the rapeseed for biodiesel, as a potential source of nitrogen to the succeeding crop. Pot experiment was conducted to evaluate the effects of winter rapeseed as green manure on mineralization and uptake of nitrogen to the succeeding corn (Zea mays L.). Result showed that total nitrogen and C/N ratio of rapeseed at the harvesting stage was 0.54% and 63, respectively. The incorporation of rapeseed without decomposition period slightly inhibited nitrogen uptake to the succeeding corn compared to those with 30 days decomposition period. The pH and EC values of soils increased by increasing the period of decomposition of rapeseed from 5.2 to 6.4 and from 0.05 dS/m to 0.21 dS/m, respectively. Significant amounts of $NH_4^+$ and $NO_3^-$ are released by incorporation of rapeseed. The succeeding corn took up 86% and 88% of inorganic nitrogen released from the rapeseed with and without decomposition period, respectively. The overall results suggested that the utilization of rapeseed residue as green manure can be an alternative source of nitrogen in corn-rapeseed double cropping system.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.4
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• pp.297-302
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• 2015

This experiment was conducted to evaluate the agronomic characteristics and forage production of Italian ryegrass cultivars at three locations (Gurae, Sungju and Cheonan) from 2013 to 2014. The experiment employed a randomized complete block design with three replications. The seven cultivars used in this experiment were 'Korwinearly', 'Florida80', 'YounbongI', 'YounbongII', 'YounbongIII', 'KeimyungI' and 'KeimyungII' varieties. Italian ryegrass varieties were seeded on October 4 at Gurae, October 8 at Seongju and October 3 at Cheonan in 2013. The Italian ryegrass varieties were harvested on April 26 at Gurae and Seongju, and on April 24 at Cheonan in 2014. Although the seven cultivars had resistance to foliar diseases and insects and high winter survival, they has little lodging resistance. The heading dates for 'Younbong I', 'Younbong II' and 'Keimyung I' were earlier than for other varieties at the three locations. Dry matter (DM) content and plant height in the early maturing cultivars were higher than in other cultivars at the three locations. The fresh and DM yields of the early maturing cultivars were also higher than others at the three locations. The results of this experiment indicate that the heading date for early maturing cultivars is earlier, and the plant height is higher than for other cultivars. Early maturing cultivars had higher DM content as well as fresh and DM yields of Italian ryegrass. Therefore, early maturing cultivars should be recommended as high-yield forage in double-cropping systems because of their superior production of forage and early heading date.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.1
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• pp.9-14
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• 2011

This experiment was carried out to breed a very early maturing variety of Italian ryegrass (Lolium multiflorum Lam.) in Grassland and Forage Crops Division, National Institute of Animal Science, RDA, Cheonan from 2009 to 2010. A new variety, 'Green farm' is a diploid variety with green in leaf color and has erect and semi-erect growth habit in late autumn and early spring, respectively. 'Green farm' was on 28 April in heading date as a early-maturing variety. 'Green farm' was also wider by 0.4 mm in flag leaf width, longer by 0.8 cm in flag leaf length and shorter by 5 cm in plant height than those of control variety, 'Florida 80', respectively. 'Green farm' was thicker in stem thickness and stronger in winter hardness than those of the 'Florida 80'. Dry matter (DM) yield (11,790 kg/ha) of 'Green farm' was similar to that of 'Florida 80'. In vitro dry matter digestibility (IVDMD), total digestible nutrient (TDN) and crude protein (CP) of 'Green farm' were 68.7, 63.3 and 10.3% which are 1.9, 1.7 and 0.6% higher than those of 'Florida 80', respectively. Acid detergent fiber (ADF) and neutral detergent fiber (NDF) of 'Green farm' were 32.5 and 54.6% which are 2.2 and 4.3% lower than those of the 'Florida 80', respectively.

• Research in Plant Disease
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• v.14 no.3
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• pp.210-213
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• 2008

The occurrence of Rice stripe virus (RSV) has been confirmed in some parts of South Korea. In the current year, this was observed to be limited in the double cropping zones of the southern region. Earlier, RSV occurred largely in the west coast regions of the country, particularly in Gangwha, Gyeonggi-do in 2001; and Buan, Jeollabuk-do and Seocheon, Chungcheongnam-do in 2007. This study was carried out to determine the nationwide extent of RSV occurrence by investigating RSV infestations in different latitudes and altitudes. Result revealed a recent reported occurrence of RSV in the southern region (Milyang, latitude $35^{\circ}$), a reported occurrence in the northern region (Cheolwon, latitude $38^{\circ}$) in 2005, and in the middle northern region of the east coast (Goseon, latitude $38^{\circ}$) as newly confirmed from this investigation. Results also confirmed the occurrence of RSV in a wide range of altitude from the plains (Milyang, 17 m altitude) to the alpine regions (Jinbu, 576 m) including the middle mountains (Sangju, altitude 285 m). The RSV occurrence in Jinbu in the alpine region and at Goseong and most of the northern end regions were confirmed only this year. The results of the present study confirmed that RSV is a fast-spreading disease in rice plant cultivation regions of the entire country.

• Journal of Plant Biotechnology
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• v.37 no.1
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• pp.25-46
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• 2010

The demand for fuel and energy resources continues to grow due to increased consumption and emerging economies in all parts of the world. With this increase in demand, crude oil prices in the international market has jumped dramatically. Global warming, which is a consequence of increasing greenhouse gas (GHG) emissions, has become scientific, social, and political concerns. To cope with global warming and energy crisis, cost-competitive biofuels are urgently needed. In addition, development of an infrastructure, which supplies energy stably and diversifies energy resources, as well as new cost-saving technologies should be developed to reduce the costs of producing biofuels. Due to high oleic acid content, rapeseed (Brassica napus L.) is currently the potential feedstock for biodiesel production in temperate zone region and the production and use of rapeseed oil is already commercialized in Europe. In Korea double-cropping (rice and rapeseed) became more prevalent because it reduces competitions from land constraints. Production of rapeseed as a biodiesel feedstock may reduce the influence of rising oil prices and nation's dependence on imported petroleum and increase job opportunities and farm incomes.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.39-45
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• 1995

This experiment was carried out at Yeongnam Crop Experiment Station since 1992 to obtain basic information on ecology of weeds and weedy rice in direct-seeded rice fields. Annual grass weeds of Echinochloa sp., Leptochloa sp., Digitaria sp. and Setaria sp.(C4 plant) and weedy rice(C3 plant) were important species in direct seeded rice compared to transplanted rice field. Period of seedling emergence of barnyard grass was varied from 8 days to 20 days depending on seeding date while it was shorter 4 to 6 days than rice. Weed occurrence and the degree of yield loss were varied by cultivation method. In direct seeding method weeds increased 2 to 3 times compared to manual transplanting. The greatest yield loss was recorded in direct seeding(40 to 100%) followed by mechanical transplanting(25 to 35%) and hand transplanting(10 to 20%), in order. Double cropping of rice-barley was reduced weeds about 30% than rice single crop due to alleopathic effect of barley residue or stubble. Weedy rice(red rice) occurrence was closely related with seeding date and tillage methods. Early seeding and reduced tillage enhanced the growth of weedy rice.