• 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.

• Korean journal of applied entomology
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• v.62 no.4
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• pp.267-275
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• 2023

Botanical extracts are employed in management of aphids. Extracts from Tanacetum cineariaiaefolium, Derris elliptica, and Sophora flavescens are widely used to control various insects. In this study, we determined concentrations of insecticidal active ingredients in commercial botanical extracts of these plants, and we investigated the time and concentration for lethal results with the green peach aphid, Myzus persicae. The concentrations of active ingredients, pyrethrins from T. cineariaiaefolium, rotenone from D. elliptica, and matrine and oxymatrine from S. flavescens, were determined after their fractionation by liquid chromatography followed by mass analysis and comparison with standard compounds. The extracts were tested for lethality in a bioassay with green peach aphids. Sprays at defined doses were applied to tobacco leaves infested with aphid nymphs. The lethal concentrations (LC50) were 20.4 ppm for pyrethrins, 34.1 ppm for rotenone, and 29.6 ppm for matrine at 48 h after treatments. At 100 ppm application levels, the lethal time LT50 was 13.4 h for pyrethrin, 15.1 h for rotenone, and 14.4 h for matrine. Kaplan-Meier analysis indicated the lethal times for the three botanical extracts at 100 ppm were significantly faster than application of a chemical insecticide, Sulfoxaflor, applied at the recommended level. These results provide baselines to develop and formulate single or mixed preparations containing botanical extracts to control green peach aphids on commercial crops.

• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.39-46
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• 2010

Environmental-friendly agriculture (EFA) is defined as the cultivation of crops with reduced amounts or without chemical-synthetic pesticides. Recently, the use of chemical pesticides has decreased significantly; therefore, we cultivated peppers following EFA- and conventional methods and compared their antioxidant activities. To accomplish this, the environmental-friendly cultivated peppers (EFPE) and conventionally cultivated peppers (CCPE) were extracted with 70% methanol and the effects of the extracts on the cell viability, intracellular ROS generation, lipid peroxidation and catalase activity of HepG2 cells were evaluated. EFPE showed a stronger protective effect against oxidative stress induced-cell death than that of CCPE. EFPE also reduced intracellular ROS generation (42.7% to 26.4%) following treatment with hydrogen peroxide more effectively than that of CCPE (24.2% to 6.3%). Furthermore, EFPE and CCPE showed protective effects against lipid peroxidation and induced catalase activity, although these effects were not statistically significant. Taken together, these results suggest that EFPE showed stronger antioxidant activities than CCPE, and thus represent evidence that EFA with biocontrol materials may improve the functional properties of crops and/or secondary metabolites with antioxidant activities when compared with conventional agricultural practices.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.4
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• pp.300-304
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• 1993

This experiment was carried out to increase the utility and productivity of forage crop as to investigate the rotation system which is suitable to cultivat at the alpine area. The treatments were 9 crops combinations including corn - rye treatment. The results obtained were as follows: 1. Rye can be cultivated satisfactorily at cold and high altitude areas such as Tae Kwan Ryong. 2. Corn, to be raised as a second crop after rye in the same year, does not have to be early (short) or medium maturity varieties in the high alpine area. 3. It is possible to increase the harvest by 30% in terms of dry melter or green crop yield through raising two crops, rye and corn, in the same year. 4. Maturity period or growth conditions of corn. as a tropical crop and the best forage crop, can improve or worsen acording to the external circumstance, such as low temperature resulting from high atitude.

• Korean Journal of Environmental Agriculture
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• v.35 no.2
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• pp.111-120
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• 2016

BACKGROUND: Arsenic (As)-contaminated groundwater used for long-term irrigation has emerged as a serious problem by adding As to soils. Phytoremediation potential of fiber crops viz., kenaf (Hibiscus cannabinus L.), mesta (Hibiscus sabdariffa L.), and jute (Corchorus capsularis L.) was studied to clean up As-contaminated soil.METHODS AND RESULTS: Varieties of three fiber crops were selected in this study. Seeds of kenaf, mesta, and jute varieties were germinated in As-contaminated soil. Uptake of As by shoot was significantly higher than that by root in the contaminated soil. In As-contaminated soil, kenaf and mesta varieties accumulated more As, than did jute varieties. In the plant parts above ground, mainly the shoots, the highest As absorption was recorded in kenaf cv. HC-3, followed by kenaf cv. HC-95. Kenaf varieties produced more biomass. In terms of higher plant biomass production, and As absorption, kenaf varieties showed considerable potential to remediate As-contaminated soil.CONCLUSION: The overall As absorption and phytoremediation potentiality of plant varieties were in the order of kenaf cv. HC-3 > kenaf cv. HC-95 > mesta cv. Samu-93 > jute cv. CVE-3 > jute cv. BJC-7370. All varieties of kenaf, mesta, and jute could be considered for an appropriate green plant-based remediation technology in As-contaminated soil.

• International Journal of Advanced Culture Technology
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• v.6 no.3
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• pp.178-186
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• 2018

Generally, in terms of the development of irrigation scheme, the efficient water resource management that supplies the irrigation water in consideration of the required time and accurate quantity to grow the crop should be conducted. The water resource assessment should precede to supply the irrigation water efficiently. The water resources assessment is divided into the water requirement analysis and the water availability assessment. In case of Korea, the major crop is paddy rice unlike crops of Africa, such as sugarcane, maize, and cassava, etc. Because it is not familiar with the method for upland irrigation development in tropical area, it needs to know the water resources assessment for irrigation scheme development about these crops. The Natama Scheme in Chiradzulu District of the Southern Malawi was selected as study area, which has tropical climate. From the collected meteorological data, the evapotranspiration was analyzed by Penman-Monteith Method and the effective rainfall was analyzed by USDA Soil Conservation Service Method. This study displays the results that for study area, the evapotranspiration varies from 2.80 mm/day to 5.51 mm/day and the effective rainfall varied from 2.1mm to 149.0mm. According to the selected crop (Green Maize, Dry Maize), the unit water requirement (UWR) and water demand (WD) considering the irrigation efficiency, irrigation time and irrigation area were estimated to be $0.00122m^3/s/ha$ and $0.0122m^3/s$ respectively. For the water availability assessment, the runoff of Natama scheme was calculated by specific yield method. The water availability was evaluated through reviewed differences of discharge between $Q80_{intake}$ and Total WD, and the irrigation water can be supplied sufficiently in the existing 10ha of Natama scheme. As a result of reviewing the extensibility of irrigable area, total WD of scheme is $0.02313m^3/s$, and $Q80_{intake}$ is $0.02387m^3/s$ ($Q80_{intake}$ > Total WD). Therefore, Natama scheme can be extended from 10 ha to 17 ha in the dry season in consideration of the $Q80_{intake}$.

• Journal of Environmental Science International
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• v.22 no.5
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• pp.625-638
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• 2013

Recently, the occurrences of droughts have been increased because of global warming and climate change. Water resources that mostly rely on groundwater are particularly vulnerable to the impact of precipitation variation, one of the major elements of climate change, are very sensitive to changes in the seasonal distribution as well as the average annual change in the viewpoint of agricultural activity. In this study, the status of drought for the present and future on Jeju Island which entirely rely on groundwater using SPI and PDSI were analyzed considering regional distribution of crops in terms of land use and fluctuation of water demand. The results showed that the precipitation distribution in Jeju Island is changed in intensity as well as seasonal variation of extreme events and the amount increase of precipitation during the dry season in the spring and fall indicated that agricultural water demand and supply policies would be considered by regional characteristics, especially the western region with largest market garden crops. Regarding the simulated future drought, the drought would be mitigated in the SPI method because of considering total rainfall only excluding intensity variation, while more intensified in the PDSI because it considers the evapotranspiration as well as rainfall as time passed. Moreover, the drought in the northern and western regions is getting worse than in the southern region so that the establishment of regional customized policies for water supply in Jeju Island is needed.

• The Plant Pathology Journal
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• v.36 no.1
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• pp.76-86
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• 2020

Cucumber mosaic virus (CMV) is damaging to the growth and quality of lettuce crops in Lanzhou, China. Recently, however, for the first time an isolate of lettuce necrotic yellows virus (LNYV) has been detected in lettuce crops in China, and there is concern that this virus may also pose a threat to lettuce production in China. Consequently, there is a need to develop a rapid and efficient detection method to accurately identify LNYV and CMV infections and help limit their spread. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) assays were developed to detect the nucleoprotein (N) and coat protein (CP) genes of LNYV and CMV, respectively. RT-LAMP amplification products were visually assessed in reaction tubes separately using green fluorescence and gel electrophoresis. The assays successfully detected both viruses in infected plants without cross reactivity recorded from either CMV or LNYV or four other related plant viruses. Optimum LAMP reactions were conducted in betaine-free media with 6 mM Mg²⁺ at 65℃ for LNYV and 60℃ for 60 min for CMV, respectively. The detection limit was 3.5 pg/ml and 20 fg/ml using RT-LAMP for LNYV and CMV plasmids, respectively. Detection sensitivity for both RT-LAMP assays was greater by a factor of 100 compared to the conventional reverse transcription polymerase chain reaction assays. This rapid, specific, and sensitive technique should be more widely applied due to its low cost and minimal equipment requirements.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.4
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• pp.695-702
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• 2020

Recently, as research on smart farms has been actively conducted, indoor environment control, such as a green house, has reached a high level. However, In the field of forestry where cultivation is carried out in outdoor, the use of ICT is still insufficient. In this paper, we propose LPWA-based forest growth environment collection and big data analysis system using ICT technology. The proposed system collects and transmits the field cultivation environment data to the server using small solar power generation and LPWA technology based on the oneM2M architecture. The transmitted data is constructed as big data on the server and utilizes it to predict the production and quality of forest products. The proposed system is expected to contribute to the production of low-cost, high-quality crops through the fusion of renewable energy and smart farms. In addition, it can be applied to other industrial fields that utilize the oneM2M architecture and monitoring the growth environment of agricultural crops in the field.

• Research in Plant Disease
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• v.14 no.1
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• pp.1-9
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• 2008

The severe damage induced by the important viruses of Rice stripe virus (RSV), Cucumber green mottle mosaic virus (CGMMV), Melon necrotic spot virus (MNSV), Tomato spotted wilt virus (TSWV) and Tomato bushy stunt virus (TBSV) was described on major crops in Korea. In 2007, the plot incidence rate of RSV was 100% on the precocious rice cultivars at the Western coastal provinces of Gyeonggido, Chungcheongnamdo, Jellabugdo and Jellanamdo, and Jejudo. RSV occurred in 2,441 ha with incidence rate of 70% over at 5 areas of Seocheon, Seosan, Boryung, Hongsung and Buyou in Chungcheongnamdo. At 4 areas of Buan, Gimje, Gunsan and Gochang in Jellabukdo, RSV occurred in 2.016 ha. CGMMV occurred on watermelon in 4.6 ha at Cheongyang area, and its outbreak was also 890 ha on oriental melon for 120 farmers with the incidence area of 23% against total cultivation areas of Seongju. MNSV was recorded firstly on watermelon in 2006 at Andong and it spread to 3 areas of Hapcheon, Gochang and Yanggu. TSWV occurred firstly at Danggin in Chungcheongnamdo in 2005. TSWV in 2006 spread to 6 areas; Taian, Hongsung and Seosan in Chungcheongnando, Namwon in Jellabukdo, and Sunchon and Kwangju in Jellanamdo. In 2007, TSWV covered 17 areas of western and southern parts; the 5 area including Taian in Chungcheongnamdo, Kwangju in Jellanamdo, Bucheon in Gyunggido, and so forth. TBSV was described firstly on table tomato at Sacheon in Kyungsangnamdo in 2004. TBSV occurred on cherry tomato at Chungju in 2006 and on table tomato at Busan area.