• Proceedings of the Korean Society of Crop Science Conference
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• 2021.10a
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• pp.152-152
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• 2021

• Proceedings of the Korean Society of Crop Science Conference
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• 2021.04a
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• pp.47-47
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• 2021

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.1
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• pp.76-82
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• 2010

Experiments were conducted to investigate seed persistence of Chinese milk vetch(CMV) in naturally reseeded rice field in 2007~2009. The seed and pods with seeds were buried in rice field at 0, 5 and 10 cm depths and retrieved from the field at one to three month intervals from July to the following year March and determined change of seed dormancy and viability. In the second experiment, persistence of the CMV seeds in the naturally reseeded rice field at different tillage methods and soil depths were also investigated after rice harvest in autumn. Burial depths and durations affected recovery rate, dormancy and viability of CMV seed. The viability loss was faster and greater in the seed than the pod with seeds and on the soil surface than the 5 or 10 cm burial depths. The recovery rate of CMV seed was decreased starting from one month as seed burial and it was significantly decreased to 52~65% for the seed in September. However, unlike the seed burial, the nearly 100% CMV seeds were recovered for burial as pod with seeds even after four months burial in both 0 and 5 cm depths. However, the recovery rate was sharply declined to below 30% at October in 2007 in both seed and pods with seeds and in the 2008/2009 experiment. the 15~47% of CMV seeds still remained even after October. The CMV had high seed dormancy of 95%, showing only 4~5% germination at the beginning in June but the seed germination increased to 25 to 35% in seed and 55 to 61% in pod with seeds in September due to breakage of hard seed dormancy. The viability loss was faster in the seed than in the pod with seeds regardless of depths of placement in the soil base on decayed seeds. Also the seed placed on the soil surface lost viability faster than the 5~10 burial depths. On the other hand, field observation in the naturally reseeded CMV rice field showed that as many as 917~2,185 CMV seeds $m^2$ were from the 0~15 cm soil depth in the rotary tillage and 250~10,105 CMV seeds in minimum tillage treatmints. The recovered seed germinated 25~33%, 23~43% but still had high percentage of hard seed having 64~72% and 51~77% even after rice harvest in autumn. These results indicate that freshly harvested CMV seeds had high level of primary dormancy and the dormancy was gradually broken in soil with time during rice cultivation periods and appreciable number of CMV seeds remained even 4 month after burial in soil. CMV plant regenerated naturally from the remained seed bank at rice harvest time in autumn. The CMV seedling still emerged even after 2 years of continuous destructive killing of emerged CMV plant by rotary tillage in naturally reseeded CMV plant in rice field, indicating that CMV seeds do persistent as least two years in soil.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.2
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• pp.180-184
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• 2015

For waxy corn hybrid development, 23 waxy corn hybrids were planted and surveyed in both pericarp thickness and sugar content. Pericarp thickness showed average 50 to $49{\mu}m$ in field and greenhouse. Results like these advanced than previous other hybrids. Also, sugar content in developed waxy corn evaluated as 13.6 to 15.3 brix. Here, we concluded that edible quality of waxy corn depended on combing of two factors. Especially, CNU11H8 hybrid at field and CNU11H-38 at greenhouse were good in both factors. Accordingly, these hybrids will be planted in next time for productivity and area adaptation.

• 한국약용작물학회:학술대회논문집
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• 2011.09a
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• pp.154-155
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• 2011

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.184-184
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• 2017

Organic matter is very important and essential factor to maintain productivity of paddy field. But as meat consumption and the demand of grain increase, the demand of forage also increased gradually in Korea. So the amount of organic matter in paddy field have been declined gradually by the reduction of return of rice straw for the forage use for cattle. There is not enough alternative resources for forage, we guess this trend of organic matter decline in paddy field would continue for the time being in Korea. So this study was performed to confirm the variation of organic matter and change of rice yield to select suitable rice cultivars which yield reduction is small in condition of organic matter decrease in paddy field. To confirm the change of rice growth and yield in condition of organic matter decrease in paddy field, we transplanted 10 rice cultivars which yield reduction are small in low fertilizer condition. We transplanted it Buan where double cropping of winter barley continues several years on June 10. Planting density were $70plants/3.3m^2$ Fertilizer amount was $N-P_2O_5-K_2O=9-4.5-5.7kg/10a$ and fertilizer split application of nitrogen was basal-tillering stage-panicle initiation = 50-20-30%. And in the other cultivation management, we observed rice standard culture of NICS. In paddy field where withdraw straws of barley and rice, the organic matter content showed tendency to decrease as the years go on. During rice cultivation season, organic matter decreased little by little, but it increased again after rice harvest season. Rice yield was more in order of Sodami, Chunghaejinmi and Saenuri. We judge that there is an advantage in rice yield of rice cultivars which have later heading date because of suitable ripening temperature. Although Sobibyeo and Shindongjinbyeo showed high yield, head rice yield decreased severely owing to chalky and cracked rice.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.570-574
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• 2013

This study was conducted to assess $N_2O$ emissions in agricultural soils of Korea under the 1996 IPCC (Intergovernmental Panel on Climate Change) methodology. $N_2O$ emissions in agricultural soils were calculated the sum of direct emission and indirect emission by the N sources and emissions by field burning of crop residues. $N_2O$ emission was highest in animal manure as 1,547 $CO_2$-eq Gg. Indirect emissions by atmospheric deposition and leaching and runoff were 1,463 and 1,753 $CO_2$-eq Gg, respectively. $N_2O$ emission by field burning of crop residues was highest in pepper due to the residue/crop ratio and field burning ratio.

• Korean Journal of Agricultural Science
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• v.39 no.4
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• pp.473-476
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• 2012

The experiment was conducted to investigate the herbicidal efficacy of imazosulfuron mefenacet by using remote-controlled aerial application (RCAA) to control annual and perennial weeds in rice paddy field. Eight annual weed species including Echinochloa crus-galli L. and three perennial weeds were dominated in the experimental field. Application of imazosulfuron mefenacet using RCAA was highly effective to control both annual and perennial weed species. No phytotoxic effect was observed in the rice based on the plant height and the number of tillers. Finally, rice yield in the imazosulfuron mefenacet treatment was as much as that in the hand weeding. This study indicates that imazosulfuron mefenacet using RCAA can be applied to control both annual and perennial weed species in rice paddy field.

• Proceedings of the Korean Society of Crop Science Conference
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• 2021.04a
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• pp.99-99
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• 2021

• Korean Journal of Organic Agriculture
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• v.6 no.2
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• pp.127-140
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• 1998

Organic farming excludes any use of the herbicide. The present paper reviews what can be done for effective weed control with existing weed control technology by farmers crop-ping paddy rice, field crops, vegetables, and fruit trees. If condition of the crop-land-al-lows diversified rotational use of the paddy land as paddy and upland field would minimize weed problem. Practising this is limited in acreage due to extremely limited governmental investment to the land for the purpose. Secondly, rotation of crops in the upland field breaking life cycles of various weeds adapted to each crop should reduce the weed problem. This is also limited as only a few crops are making the farmer profitable. In addition climate and tolerance of crops to high and low temperature. Monsoon rains and poor drainage restrict the freedom of choice. For any crop land year-round multiple cropping in denser planting shall lessen the weed problem, this multiple cropping practiced by 1960s has been abandoned due to laborshortage and increased production cost. Deep flooding the rice is impractical at present in Korean. Mulching crop with transparent, black , or combinated polyethylene sheet, hs been in-creasingly used. Progresses in development and use of mulch with allelopathic crop residues. inexpensive paper mulch, allelopathic crop residues, inexpensive paper mulch, allelopathic crop cultivar development, recently developed ex-perimental weeding machinaries, flamers, microbial herbicides, biological control organisms, soil sterilization techniques have been critically reviewed for their adoption into existing in-tegrated weeding system. Unfortunately, information on cost-benifit, and labor-benefit, for the various methods above mentioned are lacking. Urgent need for the research on rational weeding in organic farming, and herbicide low-input farming is emphasized.