• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.446-451
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• 2017

The length frequency and weight-length relationships within the loach population of Misgurnus anguillicaudatus were investigated in environment-friendly (EFP) and conventional paddy fields (CP) in South Korea, in order to identify the influences of farming practices to the loach population living in paddy ecosystem. The size-frequency of distribution of M. anguillicaudatus populations noted to differ significantly when the loach populations of the EFP and the CP were compared. The mean weight and length of the loach population in EFP was greater than those of the loaches in CP. The equations based on weight and total length relationship in EFP and CP were $W=0.000004L^{3.0747}$ and $W=0.000002L^{3.2106}$, respectively. The condition factor (K) against total length of loaches at two paddy field types with different farming practices indicates that the loach population in EFP(mean K=0.95) had access to better nutritional conditions than those in CP (mean K=0.67). It therefore appears that the size and structure of loach populations in rice paddy fields might be affected by farming practices.

• Journal of Plant Biotechnology
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• v.45 no.4
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• pp.289-298
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• 2018

The Biosafety Division of the National Academy of Agricultural Science has developed a 'Crop Composition DB' that provides analytical data on commercialized crops. It can be used as a reference in the 'Comparative Evaluation by Compositional Analysis' for the safety assessment of genetically modified (GM) crops. This database provides the composition of crops cultivated in Korea, and thus upgrades the data to check the extent of changes in the compositional content depending on the cultivated area, varieties and year. The database is a compilation of data on the antioxidant, nutrient and secondary metabolite compositions of rice and capsicum grown in two or more cultivation areas for a period of more than two years. Data analysis was conducted under the guidelines of the Association of Official Analytical Chemists or methods previously reported on papers. The data was provided as average, minimum and maximum values to assess whether the statistical differences between the GM crops and comparative non-GM crops fall within the biological differences or tolerances of the existing commercial crops. The Crop Composition DB is an open-access source and is easy to access based on the query selected by the user. Moreover, functional ingredients of colored crops, such as potatoes, sweet potatoes and cauliflowers, were provided so that food information can be used and utilized by general consumers. This paper introduces the feature and usage of 'Crop Composition DB', which is a valuable tool for characterizing the composition of conventional crops.

• Korean Journal of Environmental Agriculture
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• v.13 no.3
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• pp.279-287
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• 1994

To develop mixed pesticides of herbicide and topdressing fertilizer for paddy rice, twelve mixtures were formulated with combination of urea coated with different level of acrylic acid wax(AAW) and four herbicides, which were thiobencarb, pretilachlor, mefenacet + bensulfuron-methyl and mefenacet + bensulfuron-methyl + dymron, and effects of the mixtures for weed control, phytotoxicity and rice tillering were investigated in the laboratory and the field experiments. Release rates of active ingredient of herbicides in the distilled water were over 90% during 24 hours same as that of the reference herbicides. The release rates of nitrogen showed different patterns according to coated level of granular urea with acrylic acid wax. Optimum release rate of nitrogen as $NH_4-N$ was obtained by 5.5% AAW coating on urea for thiobencarb or pretilachlor mixture, and by 4.0% AAW coating on urea for mefenacet + bensulfuron-methyl or mefenacet + bensulfuron-methyl + dymron mixture. The pesticide active ingredients of the mixtures were stable, which showed $3.7{\sim}8.0%$ of degradation rate after 90 days of storage under $50^{\circ}C$. Effects on weed control of mixtures were acceptable for both annual and perennial weeds, while ACRI-M9213 mixture showed considerable phytotoxicity at double dose of standard. When treated the mixed pesticides to paddy rice, rice growth status including culm length, ear length, panicle number and polished rice yield exhibited no significant differences compared with the conventional treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.2
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• pp.203-209
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• 2009

Yield monitoring is one of a precision agriculture technology that is used most widely. It is spatial variability analysis of yield information that should be attained with yield monitoring system development. This experiment was conducted to evaluate spatial variability of yield and grain moisture content in rice paddy field, and their relationships to rice productivity. It is necessary to minimize sampling interval for accurate yield map making or to control cutting width of rice combine. Considering small rice plots such as $0.2{\sim}0.4$ ha, optimum size of sampling plot was below 15 m more than 5 m in with and length. In variable rate treatment field, average yield was similar, but yield variation was reduced than conventional field. Gap of yield by another plot in same field was bigger than half of average yield than yield variation was significantly big. Therefore yield measuring flow sensor must be able to measure at least 300 kg/10a more than 1000 kg/10a. Variation of moisture content in same field was not big and spatial dependance did not appear greatly. But, variation between different field is appeared difference according to weather circumstance before harvesting. Change of spatial dependence of yield was not big, because of field variation of moisture content is not big.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.969-980
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• 2016

This experiment was conducted to assess changes to the chemical properties of soil and applicability in a case of rice cultivation with organic fertilizers. The investigator applied organic fertilizers to rice cultivation for five years to examine changes to the chemical properties of soil and found that the experiment group of organic fertilizers made an ongoing increase in pH, organism content, and available phosphate content annually compared with the control group with no big differences according to the amounts of organic fertilizers used. As for the yield components, there were no statistical differences in the number of spikelets and grain filling rate between the experiment group of organic fertilizers and the control group. The experiment group recorded a higher level in 1,000 seeds weight and yield than the control group. Experiment Group 4 recorded the highest level at 29.11 kg of 1,000 seeds weight. Experiment Groups 3 and 4, which used 222 kg and 267 kg per 10 a, respectively, recorded 576 kg and 572 kg of yield, respectively, which were 4.7% and 4.1% higher than 549 kg of control group, respectively. As for the quality of brown rice, there were no statistical differences in the head rice percentage between the control and experiment group, both of which were in the range of 83.2-85.7%. As for the protein content, Experiment Groups 3 and 4, both of which used a lot of organic fertilizers, were in the range of 6.9-7.1%, which was lower than 7.5% of control group. Those findings indicate that the long-term application of organic fertilizers can improve the chemical properties of soil and increase the yield more than the conventional method of fertilizer application. The findings also suggest that it will be effective to apply 222 kg of organic fertilizers or more per 10 a.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.200-208
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• 2010

The objectives of this study were to evaluate no-tillage cover crop cropping systems for organic farming in paddy. The experiment was performed at Ihyeon series (silt loam: 9.1% sand, 73.0% silt and 17.9% clay) which affected by different management practices. Planthopper population per 20 plant was significantly higher 65.3 for conventional tillage with chemical compounds (control) compared with 3.4~9.6 for no-tillage treatments (without rice straw or green manure, amended with rice straw, hairy vetch, rape, rye, and Chinese milk vetch). Also, disease severity of sheath blight was significantly higher 10.5% for control compared to 0.7~2.9% for no-tillage treatments. Four weed species, namely Monochoria vaginalis, Ludwigia prostrata, Rotala indica, and Aneilema keisak occurred in no-tillage paddy, whereas Monochoria vaginalis occurred in control only. The pH, available phosphate, and microbial biomass C in paddy were steeply decreased in response to submerging, but increased at first heading stage. Soil $NH_4$-N content at first heading stage was significantly higher in no-tillage treatments compared with control. The grain yield was significantly higher in 4.30 Mg $ha^{-1}$ for control than other treatments. Meanwhile, rice productivity was significantly higher in 2.69 Mg $ha^{-1}$ for no-tillage amended with Chinese milk vetch compared to other no-tillage treatments. The number of panicle per plant, grain number perpanicle, and percent ripened grain were highly related for increasing the yield of rice. These results show that Chinese milk vetch was optimum cover crop for organic farming in no-tillage paddy.

• Research in Plant Disease
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• v.15 no.2
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• pp.83-87
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• 2009

Direct Polymerase Chain Reaction (PCR) method that combines biological and enzymatic amplification of PCR targets was developed for the detection of Xanthomonas axonopodis pv. glycines on soybeen seeds without DNA isolation. Primers Xag F1 and Xag R1 were designed to specifically amplify a 401 bp fragment of the glycinecin A gene of X axonopodis pv. glycines. Xag F1 and Xag R1 were used to carry out the PCR analysis with genomic DNA from 45 different bacterial strains including phylogenetically related bacteria with X axonopodis pv. glycines, and other bacterial strains of different genus and species. The PCR assay using this set of primers were able to detect X axonopodis pv. glycines with DNA concentration as low as 200 fg and $1.8{\times}10^3$ cfu/ml. The Xag was detected from the seed samples incubated for 2 hrs with shaking and the intensity of the band was increase with the incubation time of seeds. The Direct PCR assay method without DNA isolation makes detection of X. axonopodis pv. glycines on soybean seeds easier and more sensitive than other conventional methods. The developed seed assay using direct PCR method will be useful for the specific detection of X. axonopodis pv. glycines in soybean seed samples.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.487-498
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• 1992

To study the effects of different nursing methods and transplanting on the growth of rice plant (Oriza sativa L.) in southern region of Korea, Kumo-byeo, Palgong-byeo and Dongjinbyeo were transplanted from April 20 to July 20 at an interval of 15 days with 8 days old seedling (infant seedling) and 25 days old box-seedling for machine transplanting, and 45 days old conventional seedling. Threshold transplanting date in southern region of Korea were June 26 for 8 days old seedling, July 1 for 25 days old seedling and] July 11 for 45 days old seedling for Kumo-byeo, and June 21, June 30, July 10 for Palgong-byeo, June 10, June 24, July 5 for Dongjin-byeo, respectively. Yield has no uniform tendency according to the transplanting date. However, yield were greater in the order of 8 days old seedling >25 days old seedling> 45 days old seedling in Kuma-byeo and 25 days old seedling (equation omitted)8 days old seedling (equation omitted)45 days old seedling in Palgong-byeo, 45 days old seedling(equation omitted)25 days old seedling(equation omitted) 8 days old seedling in Dongjin-byeo. The optimum accumulated air temperature during yield productive stage around heading (40 days from 10 days before heading to 30 days after heading) for high yield were 1,003$^{\circ}C$ for 8 days old seedling, 1,014$^{\circ}C$ for 25 days old seedling and 1,027$^{\circ}C$ for 45 days old seedling in Kumo-byeo. And they were 1,018$^{\circ}C$, 1,015$^{\circ}C$, 1,086$^{\circ}C$ in Palgong-byeo and 998$^{\circ}C$, 984$^{\circ}C$, 949$^{\circ}C$ in Dongjin-byeo, respectively. Earlier transplanting with 8 days old seedling showed higher ratio of broken rice and green kerneled rice in Kuma-byeo, and late transplanting after July 5 showed significant high rate of green kerneled rice. Palgong-byeo and Dongjin-byeo also showed high rate of green kerneled rice at transplanting after July 5.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.853-858
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• 2011

The cultivation methods are important for determining crop yield of green manure. The effect of cultivation methods of green manure crops (GMC) on biomass and rice yield was investigated. This experiment was conducted at Sinheung series (fine loamy, mixed, nonacid, mesic family of Fluvaquentic Endoaquepts from Oct. 2007 to Oct. 2008 at the National Institute of Crop Science (NICS), RDA, Suwon, Gyeonggi province, Korea. Seven GMC (hairy vetch, barley, Chinese milk vetch, rye, crimson clover, oats, rattail fescue) were cultivated and incorporated on paddy soil by broadcasting before rice harvesting (BBRH) and partial tillage seeding (PTS). Among the three leguminous GMC, the biomass and N production were the highest at the hairy vetch of PTS. Among the four gramineae GMC, the biomass and N production tended to be higher in the rye of BBRH and barley of PTS. The C/N ratio (56.5~74.2) of rye was high compared with hairy vetch (14.1). Among the GMC, the incorporation of hairy vetch increased $NH_4$-N contents in rice paddy soil at 14 and 42 days after transplanting. These results showed that hairy vetch had no significant to rice yield compared with conventional fertilization. Therefore, hairy vetch seems to be the most efficient green manure crop as an alternatives to chemical N fertilizer in the central regions of Korea.

• Current Research on Agriculture and Life Sciences
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• v.24
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• pp.23-27
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• 2006

Seedling characteristics of rice on nursery covered with different weight of polypropylene spunbonded fabric(PSF) were investigated to determine the optimum thickness of PSF for raising of healthy rice seedlings. Four different thickness of PSF 40, 60, 80 and $100g/m^2$ were used in the seedling nursery with a conventional polyethylene(PE) film. PSF and PE were taken off in 20 days after sowing(DAS) on April and in 10 DAS on June. Plant height of 20- and 30- day old seedlings in PSF covering nursery was slightly taller as the increase of PSF thickness from $40g/m^2$ to $100g/m^2$, but number of leaves and shoot dry-weight of the seedlings was reduced. Root solidity of seedlings grown in lighter PSF ($40{\sim}60g/m^2$) covering nursery was more favorable than that in relatively heavier PSF($80{\sim}100g/m^2$). The optimum thickness of PSF for the raising of healthy seedlings was $40{\sim}60g/m^2$ PSF at sowing on April 20 and April 30 for single cropping, and $40g/m^2$ PSF on June for double cropping based on the growth characteristics of seedlings investigated at seedling nursery covered with different thickness of PSF.