• Korean Journal of Medicinal Crop Science
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• v.1 no.2
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• pp.109-114
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• 1993

This study was carried out to determine the optimum planting time for in vitromultiplied tuber of Pinellia ternata(Thunb.) Breit. The tubers were planted on April 20, May 20, June 20, July 20, August 20 and September 20 in 1990. Emergence ratios were 68 to 87% in any planting time except planting on July 20. The number of tubers per $m^2$ at harvest in plantings on May 20 and June 20 were significantly higher with 1,110 and 1,021, respectively, while in plantings after July 20, those were drastically decreased. As compared with fresh yield of planting on April 20(352kg /10a), that of May 20 was 109% and June 20 was 103%, while those of after July 20 were from 41% to 19%. There was a highly positive correlation between dry tuber yield and the number of tubers per $m^2(r=0.991^{**})$. Tuber yields for commercial use(diameter over 7.1mm) were high in planting on May 20(322kg /10a) and on June 20(299kg /10a). It was suggested that optimum field planting time for in vitro multiplied tuber of Pinellia ternata(Thunb.) Breit was from May 20 to June May 20.

• Korean Journal of Weed Science
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• v.12 no.3
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• pp.271-291
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• 1992

This study was conducted to survey the situation of direct rice seeding in Honam province in Korea to investigate problems and seek countermeasure of weed control in direct rice seeding. The total area of direct rice seeding in the south-western part of Korea (Chonbuk, Chonnam, and Chungnam) was 1650.8ha (732.1ha for direct seeding in dry field and 918.7ha for direct seeding in flooding field) in 1992. The followings are summary of the study. 1. In case of direct rice seeding in dry field, butachlor EC and G at 3 to 5 DAS was mostly selected by farmers to control weeds in dry field. Benthiocarb or chlornitrofen was also used in few cases. At 10 to 14 DAS just before rice emergence, tank misture of butachlor EC and paraquat was treated by some farmers. At 35 to 40 days, after flooding mixture of sulfonylurea derivatives was sequentially applied. Surviving weeds including barnyardgrass were finally controlled by mixture of bentazon+quinclorac WP foliage application. 2. In case of direct rice seeding in flooding field, weed control were mostly unsuccessful partially due to wrong selection of herbicide and missing the optimum application time. Three relatively successful weed control in the survey were summarized as follows. 1) Oxadiazon EC, butachlor or benthiocarb were treated just after puddling(5 to 7 days before seeding). then mixture of bentazone+quinclorac WP or sulfonylurea derivatives was sequently applied to control remaining weeds at 20 days after seeding. 2) Mixtures of bensulfuronmethyl+dimepiperate G, pyrazosulfuronethyl+molinate G, or bensulfuronmethyl+mefenacet+dymron G were applied at 11 days after puddling when barnyardgrass were at 2.0 leaf stage. Phytotoxicity was not found in case of mixture of bensulfuronmethyl+dimepiperate G but found in the other two cases but disappeared later. 3) Mixtures of bensulfuronmethyl+quinclorac G., pyrazosulfuronethyl+quinclorac G or betazone and quinclorac G were treated after 18 to 20 days after puddling when barnyardgrass was within 3.0 leaf stage. It showed good weed control in both annuals and perrenials without phytotoxicity. On the contrary, other sulfonylurea derivatives such as middle periodic herbicide showed poor weed control against barnyardgrass, so that sequential treatment of bentazone+quinclorac WP mixture was required. 3. Herbicidal characteristics and optimum application time of 45 rigistered herbicides in Korea were analyzed to discover new substitute for quinclorac mixture, that showed excellent weed control against barnyardgrass at its 3 leaf stage or older. The analysis revealed that 70% of herbicides were for preemergence and the others were post periodic herbicide. Most farmers favor to apply herbicide when rice seedlings completely rooted, at this time barnyardgrass are at 2.5-3.0 leaf stage. Therefore herbicide of which optimum application time had long is required. In this study. 6 middle periodic herbicides among sulfonylurea derivatives and 2 quinclorac mixture were selected and evaluated their weeding spectrums at different leaf stage of barnyardgrass in both soil application in flooding condition and foliage application in dry paddy field. The order of weeding spectrum in magnitude was as follows : bentazone+quinclorac WP> bentazone + quinclorac G>bensulfuronmethyl + quinclorac G>pyrazosulfuronethyl + quinclorac G> pyrazosulfuronethyl + Molinate G>bensulfuronmethyl + mefenacet + dymron G>bensulfuronmethyl + mefenacet G>bensulfuron methyl+benthiocarb G. The above results coincided with that of the survey. In conclusion, there is no proper substitute for quinclorac mixrure, which can control barnyardgrass at 3.0 leaf stage or even older. Therefore quinclorac should be supplied continuously to farmers in order to anchor direct rice seeding in Korea. Author suggested the followings to eastablish direct rice seeding technology effectively and quickly : 1) A tentatively named "The research committee for direct rice seeding" which was composed of farmers. researchers and goberment. should be eastablished to cooperate effectively. 2) Development of a pricise direct rice seeding machine for both dry and flooding paddy field. which is workable regardless of condition and varieties of seeds. 3) Study on protecting rice seed and seedling from sparrows. 4) Systematic studies of weed control techniques in direct rice seeding to standardize herbicide application. 5) Studies on farm-land reformation. techniques of precise land preparation. and direct rice seeding using an airplane.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.3
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• pp.209-218
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• 2007

This experiment was conducted to investigate effect of plowing frequency and sowing dates on the agronomic characteristics, feed value, weed yield and palatability of silage corn. Treatments were a basal treatment(C: May 5 seeding, plowing once, weeding control once), T1(May 12 seeding, plowing twice, weeding control 0 time), T2(May 19 seeding, plowing three times, weeding control 0 time, T3(May 26 seeding, plowing four times, weeding control 0 time) and T4(June 2 seeding, plowing five times, weeding control 0 time). The experiment was performed at the College of Life and Natural Sciences of Sangju University in Sangju in 2006. The plant height and ear height showed highly in order to C > T1 > T2 > T3 > T4 treatment, leaf length was the highest at T2 (96.0cm). Leaf width and number of dead leaf were the highest at C and T3 (11.2cm), C, C and T1 (4.6), respectively. Stem diameter was the highest at T3 as 31mm, while T2 was the lowest as 25mm (p<0.05). Ear circle showed highly in order of C > T1 > T4 > T3 > T4 (p<0.05), and tip filling degree was the highest at C treatment as 8.8, while T4 treatment was the lowest as 6.0 (p<0.05). The stem hardness and grain hardness were C < T1 < T2 < T3 < T4 (p<0.05). Stem saccharinity was T1(6.1%) was the highest, while T2(3.0%) was the lowest(P<0.05). Fresh yield of weed was the lowest at C treatment as 500 kg/ha, but T1 treatment was the highest as 44,100 kg/ha (p<0.05). Weed coverage rate showed highly in order of T1 > T2 > T3 > T4 > C treatment (p<0.05). Fresh yield of corn was the highest at C treatment as T3,550 kg/ha, but T4 treatment was the lowest as 65,500 kg/ha (p<0.05). Dry matter yield of corn showed highly in order of C(26,978 kg/ha) > T1(26,130 kg/ha) > T2(20,255 kg/ha) > T3(20,255 kg/ha) > T4(17,508 kg/ha) treatment (p<0.05). Crude protein content was T1(7.69%) > T4(7.42%) > T2(6.34%) > T3(5.99%) > C(5.91%) treatment (p<0.05), and Crude fat content showed highly in order of C (2.13%) > T1(2.04%) > T2(1.96%) > T3(1.95%) > T4(1.84%) treatment. Relative palatability of Holstein, Korean native goat and spotted deer was the highest at C treatment, but Korean native cattle was the highest at T1 treatment.

• Journal of Sericultural and Entomological Science
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• v.16 no.1
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• pp.67-75
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• 1974

The studies are to know how much cocoon crops is damaged by the stained leaf with nicotine produced from the tobacco field cultivated in mulching system in spring season and by residual nicotine in autumn season. Furthermore, the new knowledges are to make both industries keep up with their development. In spring season mulberry Held is located higher on the West-North of tobacco held below 20 degrees of slope and with 36 per cent of East-South wind and 18 per cent of South wind blowing from tobacco fold to the mulberry fold. In addition, silkworm larvae are fed with the mulberry leaf produced in the different plots placing by the different distances, l0m, 25m, 50m, 80m, and loom far from the tobacco Held as a control and it is also considered that narcotic larvae including the dead larvae are not observed. On the other hand, it is noted that better leaf quality and abundant growth of mulberry tree is produced from the mulberry fold closer to the tobacco field and with a low slope. 1) Maximum weight of larval body at the 5th stage is damaged by the stained leaf with the nicotine up to 25m far from the tobacco held. 2) The larvae fed with the mulberry leaf in mulberry Held up to 25m far from the tobacco fold produce small number of the fresh cocoons per 1 liter. 3) Low single cocoon weight and low cocoon shell weight are produced by the poison damaged larvae fed with the mulberry. leaf up to 25m far from the tobacco field and weight of cocoon shell is damaged higher than the single cocoon weight. It is resulted in low percentage of cocoon shell. 4) Cocoon yield including the double cocoon from 10,000 larvae is decreased by the larvae fed with the stained leaf in the mulberry fold up to 25m far from the tobacco fold and 19 per cent of cocoon yield is decreased with 2.4kg of cocoon yield in l0m plot and with 2.5kg of cocoon yield in 25m plot at the first season and at the 2nd season with 1.8kg o( cocoon yield in l0m plot and with 11.5kg of cocoon yield in 25m plot, 11 per cent and 9 per cent of cocoon yield including double cocoon from 10,000 larvae is decreased, as compared with the control, respectively. With these results, it is observed that nicotine damage is occurred to the silkworm larvae if the larvae are fed with the leaf in the mulberry Held within 25m-50m far from the tobacco field.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.645-658
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• 2004

To investigate the effects of conjugated linoleic acid added diet feeding on CLA accumulation and quality characteristics of manufactured press ham using CLA accwnulated pork loin meat. The CLA used to add in diet was chemically synthesized by alkaline isomerization method with com oil. Pigs were divided into 5 treatment groups(4 pigs/group) and subjected to one of five treatment diets(0, 1.25% CLA for 2weeks, 2.5% CLA for 2weeks, 1.25% CLA for 4weeks and 2.5% CLA for 4weeks, CLA diets; total fed diets) before slaughter. Pork loin were collected from the animals(110kg body weight) slaughtering at the commercial slaughter house. Manufacture press ham using CLA accumulated pork loin meat were vacuum packaged and then stored during 1, 7, 14, 21 and 28 days at 4$^{\circ}C$. Samples were analyzed for general compositions, physico-chemical properties(pH, color, shear force value), TBARS. pH value of CLA treatment(T4) was increased significantly than that of oontrol(P<0.05). pH of control and CLA treatments were increased significantly as the storage period passed(P< 0.05). Crude fat content of CLA treatment groups was significantly higher than the control pork (P<0.05). Meat color(CIE $L^*$, $a^*$$b^*$

• Korean Journal of Breeding Science
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• v.51 no.4
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• pp.496-503
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• 2019

The soybean cultivar, 'Saegeum', has been developed for preparing soy-paste and tofu. The soybean cultivars 'Daepung' and 'SS98207-3SSD-168' were crossed in 2003 to obtain 'Saegeum'. Single seed descent method was used to advance the generation from F₃ to F₅, and the plant lines with promising traits were selected from F₆ to F₇ by pedigree method. The preliminary yield (PYT) and advanced yield trials (AYT) were conducted from 2009 to 2010, and the regional yield trial (RYT) was conducted in 12 regions between 2011 and 2013. The morphological characteristics of 'Saegeum' were as follows: determinate plant type, white flower, tawny pubescence color, and brown pod color. Flowering and maturity dates were August 2, XXXX and October 17, XXXX, respectively. Plant height, first pod height, number of nodes, number of branches, and number of pods were 79 cm, 18 cm, 16, 2.3, and 44, respectively. The seed characteristics of 'Saegeum' were as follows: yellow spherical shape, yellow hilum, and the 100-seed weight was 25.4 g. 'Saegeum' was resistant to bacterial pustule and SMV in the field test, and its lodging resistance was mildly strong, whereas its shattering resistance was excellent. The ability of this cultivar to be processed into tofu, soybean malt, and other fermented products was comparable with that of 'Daewonkong'. The yield of 'Saegeum' in the adaptable regions was 3.02 ton ha^-1. Thus, 'Saegeum' is adaptable to mechanized harvesting because of its high first pod height, as well as lodging and shattering resistance. (Registration number: 5929)

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.460-466
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• 2009

Carbon fixation and density of crops are important to estimate carbon uptake or emission by agricultural production activities and to establish life cycle inventory of crops for assessment of climate change impact. In this study, regional carbon fixation and density in each part of 14 crops, harvest index, and ratio of aboveground to underground were investigated to estimate biomass of 14 crops in Korea by using agricultural statistics data. Biomass yield of potato was $16.5ton\;ha^{-1}$, which was the highest, and those of rice, sweet potato, and garlic were $10.5ton\;ha^{-1}$, $8.7ton\;ha^{-1}$, and $7.5ton\;ha^{-1}$ respectively. Biomass yield of Green onion was the lowest as $2.8ton\;ha^{-1}$. Carbon density of 14 crops were in the order of potato ($6.4ton\;ha^{-1}$), rice ($4.2ton\;ha^{-1}$), sweet potato ($3.4ton\;ha^{-1}$), rape ($2.9ton\;ha^{-1}$) and garlic ($2.8ton\;ha^{-1}$). Regional distribution of carbon contents for each crop mapped revealed that carbon fixation of rice, soybean, sesame, garlic, and green onion were the highest in Jeonnam province, barley, red pepper, and watermelon in Gyeongnam, perilla in Chungnam, peanut in Gyeongbuk, rape and carrot in Jeju, sweet potato in Gyeonggi, potato in Gangwon. The results can be applied for assessing life cycle inventory of crops and crop productivity using remotely sensed data.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.459-465
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• 2012

This study was conducted to obtain investigated characteristic factors which has an influence on nitrous oxide ($N_2O$) emissions related to the environment change of nitrogen application level, rainfall and temperature. It was done by the carrot cultivation at black volcanic ashes soil in the experimental field of Jeju Special Self-governing Province Agricultural Research and Extension Services from 2010 to 2011. During the carrot cultivation period, the more amount of nitrogen fertilizer applied, the more amount of $N_2O$ emissions were released. Generally $N_2O$ emissions were so deeply released to climate as that in the first and middle of cultivation with heavy rainfall released amount is high, otherwise it was released very low at the end of cultivation and drought season. $N_2O$ emissions type was considered to relate with the rainfall pattern and soil water content. We obtained the result correlated with $N_2O$ emissions, in 2010, as the soil water and soil temperature were significant to $0.5718^{**}$ ($r$) and $0.4908^{**}$ ($r$) respectively, but soil EC was not significant to 0.2704 ($r$). In 2011, soil water was significant to $0.3394^*$ ($r$), but soil temperature and soil EC were not significant to 0.2138 ($r$) and 0.2462 ($r$) respectively. Also, $NO_3$-N and soil nitrogen ($NO_3-N+NH_4-N$) were not significant to 0.0575 ($r$) and 0.0787 ($r$) respectively. During the carrot cultivation period, the average emissions factor released by the nitrogen fertilizer application for 2 years was presumed to be 0.0025 $N_2O$-N kg / N kg. This factor was 4 times than the IPCC (0.0100 $N_2O$-N kg / N kg) factor.

• Korean Journal of Agricultural Science
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• v.13 no.1
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• pp.103-112
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• 1986

This study was carried out to prevent the entwining of rice straw on rotary shaft and blade where rice straw was spreaded on paddy field as an organic source before rotary tilling. The rotary tillage was conducted in the paddy field having the soil moisture contents of 30%, 39%, 59% in dry basis and spreaded rice straw (450kg/10a) of 30cm, 45cm, 90cm length with the edged curve angles of rotary blade of $30^{\circ}$, $40^{\circ}$, $50^{\circ}$, $55^{\circ}$ at Yuseung area. And the test were performed on the plot which has width of 30cm and 5cm length and the quantity of entwined rice straw was analized. The test results were summarized as the followings. 1. Entwining phenomenon of rice straw was decreased as the blade edged curve angle increased. The edged curve angle of rotary blade must be determind by considering the characteristics of soil cutting resistance, tilling torque and entwining phenomenon of rice straw. But according to the entwining phenomenon of rice straw only, the edged curve angle of rotary blade should be bigger than $55^{\circ}$ for design. 2. Amount of entwining rice straw was minimized when soil moisture contents was 30 percent (d. b.). It would be better that rotary tillage is performed when soil moisture contents is lower than 30 percent in dry basis. 3. Amount of entwining rice straw was minimized when the length of rice straw was 30cm with $55^{\circ}$ edged curve angle. Therefore, it would be better to chop rice straw as 30cm. 4. Entwining phenomenon of rice straw was decreased as the forward speed decreased. To decrease the entwining rice straw, rotary tillage should be done with forward fist gear (0.35m/s).

• Korean Journal of Soil Science and Fertilizer
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• v.1 no.1
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• pp.117-123
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• 1968

A simplest and best method to find out lime requirement for Korean soils is described. Twenty six top soil samples were collected from various localities and chemical characteristics were dertermined. Three different buffer curve methods were employed as the standard to find out the most reliable test for lime requirement. In addition, the lime requirement test by the Shoemaker's and Woodruff's as well as the O.R.D. kit method were compared with the most reliable buffer curve method. The results may be summarized as follows. 1. The regression equation of the most reliable lime requirement by buffer curve method, y, on percent base saturation of various soils, X, was y=9.69-0.106 X and the negative correlation coefficient r=-0.84 was statistically significant at 5% level. 2. Lime requirement test by the best, buffer curve, method was more well correlated with the sum of exchangeable hydrogen and exchangeable aluminum contents of the soil samples than the exchangeable hydrogen content only. 3. The ordinary buffer curve method for lime requirement is more reasonable than the lime requirement test by the buffer curve prepared after addition of 1 normal potassium chloride or calcium chloride solutions. 4. The lime requirement tests by the most reasonable buffer curve method, X, and by the Woodruff's, the Shoemaker's and O.R.D. kit were compared. The best method for laboratory lime requirement test was the Shoemaker's method and the O.R.D. kit method also was good enough for the field test and these two method are recommended as the unified method of lime requirement test in each soil testing laboratories throughout Korea.