• Journal of Biosystems Engineering
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• v.7 no.2
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• pp.36-44
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• 1983

Farm population was rapidly decreasing due to shift of the people from farm sector to the non-farm sector caused by the economic growth of the country. Especially, a great shortage of farm labor in busy farming period in June and October is becoming a serious problem in maintaining or promoting land productivity. The peak of labor requirement in summer is caused by rice transplanting and barley harvesting. In order to reduce the restrictions imposed on farm management by the concurrence of labor requirement and the lack of labor, the experimental study for mechanization of barley harvesting has been carried out in the fields. 1. The machines for barley harvesting were knap-sack type reapers, windrow reaper (power tiller attachment), binder and combine. The order of higher efficiency of machine for barley harvesting was combine, binder, windrow reaper (WR), knapsack type reaper 1(KSTR1), and knap sack type reaper 2(KSTR2; mist and duster attachment). 2. The ratio of grain loss for the manual, binder, and combine plot was about four percent of total field yield. 3. The total yield of barley in 35 days and 40 days harvesting after heading were 514 kg and 507kg per 10 ares respectively. The yield of 35 days-plot was higher than other experimental plots. 4. The lowest yield was recorded in 30 days-plot due to the large quantity of immatured grains and having lighter 1000-grain weight. The ratio of immatured grains was 2.66 percent and 1000-grain weight was 29.4 grams. 5. The total harvesting cost of the windrow reaper was 10,178 won per 10 ares. It was the lowest value compared to other machines. The next were combine, binder, KSTR1, KSTR2, and manual in sequence. As a result, the optimum time of barley harvesting for mechanization was 35-40 days after heading. Combine, binder, and windrow reaper were recommended as the suitable machines for barley harvesting in the work efficiency. However, in total harvesting cost, the windrow reaper was the most promising machine for barley harvesting.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.254-258
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• 2002

The characteristics of yield and quality in 3 rice varieties according to harvest time of 40, 50, 60 and 70days after heading(DAH) was investigated to obtain basic information for the production of high quality rice. The protein content of milled rice increased significantly as increase the ripening period from 40 to 70DAH. The palatability value measured by rice taster was the highest in ripening period of 40DAH and decreased with increase of ripening period. The optimum time for harvest in terms of both rice yield and quality was 4050DAH in Daejinbyeo, and 4060DAH in Seojinbyeo and Chucheongbyeo, however, it was considered to be 4050DAH only for rice quality. The palatability value measured by rice taster showed a highly negative correlation with protein content of milled rice(1=-0.94$^{**}$) and cumulative ripening temperature(r=-0.79$^{**}$).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.3
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• pp.210-219
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• 2021

In recent years, air temperature has been increasing rapidly compared to the 1980s because of global warming. This increase in temperature reduces the yield and quality of rice; therefore, measures are needed to prevent such effects and ensure food security. The early maturing type (EMT) of rice is mainly cultivated in the central northern mid-mountainous area (CNMA). This study was conducted to shift the transplanting date of EMT and to examine the adaptability of the mid-maturing type (MMT) or mid-late maturing type (MLMT) in the Jecheon region of the CNMA to address global warming. The air temperature increased by 0.7-0.9℃ in the 2010s, compared to that in the 1980s, and was similar to other decades during the ripening period. Over the past 35 years, considering rice quality, the heading date of the Odae variety has arrived sooner by approximately 10 days, the ripened grain ratio has increased by more than 10%, and the thousand grain weight; however, the mean temperature at 40 days after heading has increased by more than 2℃. The late marginal heading date in the Jecheon region was determined as August 11 based on the accumulated temperature of 880℃ and August 15 based on 840℃ for 40 days after heading. According to different transplanting dates, milled rice yield per 10 a was the highest at 567 kg with June 10 in EMT, 595 kg with June 10 in MMT, and 572 kg with May 30 in MLMT. Considering the late marginal heading date, rice yield, and quality, the optimum transplanting date was June 15 in EMT, June 5 in MMT, and May 30 in MLMT in the Jecheon region of CNMA. Owing to global warming, MMT and MLMT are expected to be reliably cultivated in the CNMA.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.261-261
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• 2017

This study was carried out to provide basic data for spreading rice direct seeding by inducing stabilization of seedlings, yield and quality according to sowing times in rice direct seeding cultivation. In 2016, 'Sukwang' was seeded 3 times by 10 days interval on May. 10, 20, 30 and 6kg/10ha of seeding rate respectively in Iksan. In summary, the number of rice seedling establishment was higher than the optimum seedling establishment level at all sowing periods and the seeding rate was better as the sowing period was delayed. Weed development by sowing was the highest at early sowing, May 10, and decreased at late sowing. Heading dates were delayed by 3days for sowing on May 10, 7days for sowing on May 20, and 11 days on sowing on May 30. Rice yield increased with the delay sowing time and compared to the transplanting. It was 84% in sowing on May 10, 94% in sowing on May 20, and 99% in sowing on May 30. In addition, head rice ratio and head rice yield increased according to delayed of seedling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.4
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• pp.470-476
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• 1986

In order to find out the optimum seeding date of Job's tears, this study was investigated ecological characters, yield components and yield of Jang Seong native variety at 6 seeding dates (March 20, March 30, April 10, April 20, April 30 and May 10). Emergence period and heading period were shortened as the seeding date was late, and the number of leaves on the main stem was increased as the seeding date was early. Maturing period was 63-66 days when we seeded in March 20, March 30, April 10 and April 20, and it was delayed 68-77 days when we seeded on April 3$^{\circ}$ and May 10. Culm length was longest in April 10 seeding (it was 186.6 cm), and it grew short in the early and the late seeding, but there was no significant difference among seeding dates. Stem diameter was thickest in April 10, and April 20 seeding, that is, thickened to 10.1 mm, and it was thin in the early and the late seeding. Productive tiller number per hill was increased most in April 10 and April 20 seeding, that is, increased to 6.2, and it was decreased in the early and the late seeding. 100 grain weight was heaviest in April 10 seeding; it was 10.7 g, and it was light in the early and the late seeding. Ripeness rate was highest in April 10 seeding (87.4%), and it was lowest in May 10 seeding (76.3%). Grain yield was highest in April 10 seeding (602.8kg per l0a); therefore this period is regarded as optimum seeding date. C. protein, C. fat, C. fiber and C. starch showed significant difference among seeding dates, and C. protein showed possitive correlation (r =0.9811 **) and C. fiber Negative collelation (r =-0.8937*) with seeding dates.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.2
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• pp.85-92
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• 2007

This study was carried out to select the promising forage crops fer forage production in paddy field of YARI, RDA, Milyang from 1999 to 2001. The species of forage crop used in this experiment were barley(5 varieties), wheat(2), rye(3) and Italian ryegrass(IRG, 3). Stages of heading, milk and yellow ripe of barley were $20{\sim}24$ April, $6{\sim}10$ May and $21{\sim}24$ May, respectively. In milk to yellow ripe stage, dry matter(DM) yield of barley was $7.89{\sim}9.66$ MT per ha, and averaged ADF and NDF contents were $26.9{\sim}33.3%\;and\;53.1{\sim}59.2%$, respectively. Albori and Naehanssalbori were the most promising varieties among the barley. The growth of wheat was a little late compared to that of barley, but it seemed to be crop having higher forage yield and nutritive value. In milk to yellow stage, DM yield of wheat was $9.13{\sim}10.38$ MT per ha, and nutritive value of wheat was very good(ADF $25.9{\sim}31.7%$ and NDF $53.3{\sim}55.8%$). Heading stage of rye was $20{\sim}24$ April, and it seemed to be suitable far harvest at heading to flowering stage because of heavy lodging after flowering. In flowering stage, DM yield of rye was 13.64 MT per ha, and nutritive value of rye was the lowest among 4 species(ADF $33.1{\sim}38.0%$ and NDF $56.4{\sim}65.0%$). Heading stage of early maturing IRG was 2 May and it seemed to be suitable for harvest at flowering stage of middle May in cropping system. In flowering stage, DM yield of early type IRG was 5.51 MT per ha, and averaged ADF and NDF contents were $30.1{\sim}34.7%\;and\;59.7{\sim}60.5%$, respectively. The results demonstrated that the promising forage crops far forage production in paddy field were rye, barley, early maturing IRG and wheat in Yeongnam region. In Southern region, rye harvesting at early May was recommended when considered middle May of rice transplanting period, and barley(Albori and Naehanssalbori) and early maturing IRG harvesting at middle May were recommended when considered late May of rice planting period. And also, wheat with high nutritive value and possibility for harvesting at late May were recommended in case of transplanting period at early June.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.3
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• pp.217-224
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• 2004

This study was carried out to select the promising forage crops for forage production in paddy field of HARI, RDA, Iksan from 1999 to 2001. The species of forage crop used in this experiment were barley(5 varieties), wheat(2), rye(3) and Italian ryegrass(IRG, 3). Stage of heading, milk and yellow ripe of barley were 26 $April{\sim}l$ May, middle May and late May, respectively. In milk to yellow ripe stage, dry matter(DM) yield of barley was $6.64{\sim}10.47$ MT per ha, and averaged ADF and NDF contents were $31.6\%\;and\;62.2\%$ respectively. Albori was the most promising variety among the barley). The growth of wheat was a little late compared to that of barley, but it seemed to be crop having higher forage yield md nutritive value. In milk to yellow stage, DM yield of wheat was $7.51{\sim}11.96$ MT per ha, and nutritive value of wheat was high(ADF $30.6\%$ and NDF $60.1\%$). Heading stage of rye was $25{\sim}27$ April, and it seemed to be suitable to harvest at heading to flowering stage because of heavy lodging after flowering. In flowering stage, DM yield of rye was 17.26 MT per ha, and nutritive value of rye was the lowest among 4 species(ADF $38.6\%$ and NDF $65.5\%$). Heading stage of early maturing IRG was 30 April and it seemed to be suitable for harvest at flowering stage of middle May in cropping system. In flowering stage, DM yield of early type IRG was 10.77 MT per ha, and averaged ADF and NDF contents were $31.6\%\;and\;59.2\%$, respectively. The results demonstrated that the promising forage crops for forage production in paddy field were rye, barley, early maturing IRG and wheat in Honam region. In Southern region, rye harvesting at early May was recommended when considered middle May of rice transplanting period, and barley(Albori) and early maturing IRG harvesting at middle May were recommended when considered late May of rice planting period. And also, wheat with high nutritive value and possibility for harvesting at late May were recommended in case of transplanting period at early June.

• Korean Journal of Soil Science and Fertilizer
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• v.5 no.2
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• pp.65-74
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• 1972

A local rice variety, Jinheung and newly bred IR667-Suwon 214 were grown in $5m^2$ concret pot with two spacings and two nitrogen levels and their ripening structure and its function were comparatively investigated to elucidate the causes of unusually low ripened grain ratio of IR667 lines. The following differences between two varieties were found. 1. Though IR667 had much lower ripened grain ratio (64%) than Jinheung (85%) grain yield(790 kg/10a) of IR667 was higher than that (760 kg/10a) of Jinheung. 2. Number of ripined grain per net assimiration rate (NAR) at 10 days after heading was a little higher in IR667 (6,490) than in Jinheung (6,360) consiting to lower grain weight ($29.9{\times}10^{-3}g$) in IR667 than $31.2{\times}10^{-3}g$ of Jinheung. But number of total grain per NAR was much higher (10,530) in IR667 than 7,290 of Jinheung indicating that it was the probable cause of low ripened grain ratio of IR667. 3. Extinction coeificient (K) was 0.115 in IR667 and 0.200 in Jinheung, thus IR667 could construct greater ripening structure per unit area. 4. Number of grain per LAI was decreased with increasing LAI at heading and the decreasing rate was similar for both IR667 and Jinheung. 5. Critical leaf area index at which crop growth rata (CGR) is maximum was 6.5 for IR667 and 5.2 for Jinheung. Below 5.2 of LAI net assimilation rate was always higher an Jinheung throughout the growing season. 6. The estimated optimum leaf area index having maximum grain yield was 7.4 for IR667 and 6.2 for Jinheung at 10 days after heading. However, actual leaf area index was 6.2 for IR-667 and 4.7 for Jinheung and these were even below critical leaf area index. 7. The decrease of LAI during ripening period was great in IR667 but photosynthesis per $m^2$ was decreased more rapidly in Jinheung. 8. Net assimilation rate (NAR) decreased with the increase of LAI at any time of ripening period. The decreasing rate of NAR with the increase of LAI was greater in IR667 with ripening. The greater decreasing rate of NAR in IR667 seemed to be attributed to low photosynthetic activity and high respiratory loss due to the requirement of higher optimum temperature of ripening. 9. Grain yield-ripened grain ratio curve showed less contribution of dry matter yield after heading to grain yield in IR667 than in Jinheung due to unfavorable ripening environment(specialy air temperature) indicating that yield of IR667 could most effectively increased through the improvement of ripening environment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.166-171
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• 2017

For high-quality colored rice production, the cultivation environment is a critical factor. The major environmental factor is temperature, which includes the accumulated and average temperature during vegetative and reproductive stages. Generally, during the cultivation period, the temperature can be controlled by shifting the transplanting date. This study was carried out to determine the optimum transplanting date for high-quality red-colored rice production. Four red-colored rice varieties (Jeokjinju, Jeokjinjuchal, Hongjinju, and Gunganghongmi) were used as test materials. The transplanting dates were May 20 and June 5, 20, and 30 in 2015~2016. The most variable factor controlled by the transplanting date was the grain filling rate. The varieties transplanted on June 30 showed low yields owing to the decrease in the grain filling rate. In contrast, the polyphenol content increased with increasing delay in the transplanting date. Collectively, these two results indicate that the optimum transplanting date was June 20. The average temperature for 30 days after the heading date (30DAH) highly affected the polyphenol content. A lower temperature during the 30DAH induced higher polyphenol contents but also caused low yield. The optimum 30DAH temperature for obtaining a higher yield and polyphenol content was $22{\sim}23^{\circ}C$. Using the average 30DAH and accumulated temperatures, the optimum transplanting date was calculated as June 18 to 24 in Miryang region. The optimum transplanting date of Kyeungsangnamdo region was approximately mid-June to early July, and that of Kyeungsangbukdo region was approximately early to mid-June.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.699-705
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• 1997

This experiment was conducted to find out an optimum direct seeding date for rice in the southern alpine area of Korea as direct seeding method being considered as the most labor-saving method. A cultivar which was sprouted, Keumobyeo, was sown on the surface of flooded paddy from April 25 to May 15 with 5-day interval. The growth characters such plant height, tiller numbers, yield and its components as well as air temperatures were observed. Earlier sowing showed longer plant height and greater tillers than later sowing. Accumulated temperatures in the different growth stages varied from 1,010 to 1,052$^{\circ}C$ during the period from seeding date to maximum tillering stage, and from 1,785 to 1,846$^{\circ}C$ during the period from seeding to heading dates. The growth of rice sown up to May 5 showed comparatively good when compared to that of machine-transplanted rice, even though the grain yield was not competitive to that of machine-transplanted rice. Highly negative correlation coefficients were found between accumulated temperature during the period of first 30 days after seeding dates and the number of panicles, the number of spikelets per square meter, and grain yield. Regression equation between direct seeding date(X) and yield(Y;MT /ha) was $\hat{Y}$ =3.80990＋0.06207X-0.00174 $X^2$($R^2$=0.704), from which optimum seeding date for direct seeding method in alpine area was estimated to be on April 25 to May 1.