• Korean Journal of Weed Science
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• v.31 no.1
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• pp.34-40
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• 2011

Cover crop can be used to suppress weeds by competition for light and nutrient. Objective of this study was to evaluate the effectiveness of legume cover crops on change of weed community in no-till corn cultivation. Two legume cover crops, hairy vetch and crimson clover were grown in the field, and succeeding corn was sown on 4 May, 2010. The distribution of weed was surveyed at 15 April, 1 June, and 20 August. At 15 April, the weed biomass in hairy vetch field was higher than in crimson clover field. The dominant weeds were Capsella bursa-pastoris L. and Stellaria aquatica L. in hairy vetch and crimson clover fields, respectively. At vegetative stage of corn, occurred weeds in hairy vetch and crimson clover fields were four and six species, respectively, while the weed was occurred with nine species in conventional. Also the dry weight of weed was decreased by 82 and 75% in hairy vetch and crimson clover fields compared to conventional. On the other hand, after harvest of corn, occurred weed in hairy vetch, crimson clover and conventional was five, four and five species, respectively. Dry weight percentage of occurred weed in conventional was 23.5%, and the value was higher than 13.8 and 14.7% in hairy vetch and crimson clover fields, respectively. Stellaria aquatica L. as winter annual weed only occurred in cover crop field during corn growing season. It is these possibilities that low soil temperature and light interception by soil cover of legume cover crop.

• Journal of Plant Biotechnology
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• v.41 no.1
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• pp.56-63
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• 2014

Using commercial radish varieties for processing, about 30% of radish was discarded due to the root shape and low purity. To raise the processing ability, we tried to develop a new variety producing H-shaped root. As another characteristic required in variety for processing is high purity, we tried to raise purity using simple sequence repeats (SSR) markers for testing seed purity in every segregating generation. To develop Male-sterile (MS) seeding parent, we crossed commercial variety of 'Gwan dong spring' and 'Gyeo ryong spring'. One elite inbred was selected as recurrent parent for the MS plant. The major horticultural traits of selected inbred line were disease resistance, late bolting, heat resistance and bright green root top color. To develop pollen parent, we crossed commercial variety of 'Tae sang king' and 'Seoul spring'. We used individual selection method to develop H-shaped hard root and disease resistant inbred. In each segregating generation, we selected one plant based on phenotype and the uniformity of selected plant was tested by SSR markers using self-pollinated seeds. In the first segregating generation, 64.6% of sib plants shared the same band in PCR amplification using ACMP-490 primer and 66.7% using cnu-316 primer. The uniformity of segregating generations using ACMP-490 and cnu-316 raised in second generation to 68.8%, 70.8%, respectively; in third generation to 93.8%, 100%; in fourth generation to 93.8%, 100%; in fifth generation to 95.8%, 100%; in sixth generation to 100%, 100%. A novel cross was made using selected MS parent and pollen parent. When we checker the horticultural traits using autumn cultivation, the novel cross variety produced H-shaped root comparing other commercial varieties and produced highly uniform radish. Thus we registered this novel cross variety as 'YR ORE' at 2013 (Registration No. 4550).

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.181-190
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• 2003

An investigation was conducted on the aquatic environment of the Okchon Stream watershed six times from May to September 2002. The results of investigation revealed that variation of environmental factors were quite significant for each stream and reach, showing a significant difference between running water and stagnant water. Aquatic nutrients were relatively low in the upstream, gradually increasing as the influx of treated wastewater into the stream increased. This suggests that the point source definitely affected the nutrient content of the stream. In particular, the variations of SRP and $NH_4$ were very distinct in the watershed compared to other nutrients. Thus, it can be considered as a major factor in evaluating the effect of treated wastewater. Immediately after the influx of treated waste-water, the average content of SRP rose to 919.3 ${\mu}g$ P/l. This was a very effective level in the watershed, suggesting that the percentage of the nutrients in the water was controlled by the content of P. The constant supply of treated wastewater was found to be a critical factor in triggering the increase in chl-a in the embayment of the stream. With the proliferation of the blue-green algae, the content of chl- a ranged 234.5${\sim}$1,692.2 ${\mu}g/l$. The maximum standing crops exceeded $1.0{\times}10^6$ cells/ml in August, which was more than 200 times the level for red tide in the freshwater. This result was well reflected in other environmental factors, with 100% of AFDM/TSS reflecting the severity of water pollution by algae. Therefore, the reduction of P and N con-tents in the treated wastewater is critical in improving the aquatic environment of the stream as well as water quality management for the reservoir.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.2
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• pp.142-149
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• 2016

'Shinseong', a winter forage triticale cultivar (X Triticosecale Wittmack), was developed at the Department of Rice and Winter Cereal Crop, NICS, RDA in 2015. The cultivar 'Shinseong' was selected from the cross RONDO/2$^*$ERIZO_11//KISSA_4/3/ASNO/ARDI_3//ERIZO_7 by CIMMYT (Mexico) in 1998. Subsequent generations were handled in pedigree selection programs at Mexico from 1999 to 2004, and a line 'CTSS98Y00019S-0MXI-B-3-3-5' was selected for earliness and good agronomic characteristics. After preliminary and advance yield testing in Korea for 3 years, the line was designated 'Iksan47'. The line was subsequently evaluated for earliness and forage yield in seven locations, Jeju, Iksan, Cheongwon, Yesan, Gangjin, Daegu, and Jinju from 2013 to 2015 and was finally named 'Shinseong'. Cultivar 'Shinseong' has the characteristics of light green leaves, yellow culm and spike, and a medium grain of brown color. The heading date of cultivar 'Shinseong' was April 24 which was 3 days earlier than that of check cultivar 'Shinyoung'. The tolerance or resistance to lodging, wet injury, powdery mildew, and leaf rust of 'Shinseong' were similar to those of the check cultivar. The average forage dry matter yield of cultivar 'Shinseong' at milk-ripe stages was $15MT\;ha^{-1}$, which was 3% lower than that ($15.5MT\;ha^{-1}$) of the check cultivar 'Shinyoung'. The silage quality of 'Shinseong' (6.7%) was higher than that of the check cultivar 'Shinyoung' (5.9%) in crude protein content, while was similar to the check cultivar 'Shinyoung' in acid detergent fiber (34.6%), neutral detergent fiber (58.6%), and total digestible nutrients (61.6%). It showed grain yield of $7.2MT\;ha^{-1}$ which was 25% higher than that of the check cultivar 'Shinyoung' ($5.8MT\;ha^{-1}$). This cultivar is recommended for fall sowing forage crops in areas in which average daily minimum mean temperatures in January are higher than $-10^{\circ}C$.

• Journal of agriculture & life science
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• v.45 no.4
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• pp.1-11
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• 2011

The aim of this study was development of natural antifungal compounds from softwood. We investigated antifungal activities of extracts from Pseudotsuga menziesii and Chamaecyparis obtusa against Tricholderma genus which is virus causing green mold disease and analyzed antifungal compounds by Gas chromatography -Mass Spetrometer. Extracts from P. menziesii had inhibition activities against Tricholderma genus on 1,000 ppm and had high antifungal activities against T. viride by 70.1%, T. harzianum by 67.3% and T. aggressivum by 64.7% on 4,000 ppm. And extracts from C. obtusa had antifungal activities against Tricholderma genus on 1,000 ppm and had high antifungal activities against T. viride by 63.2%, T. harzianum by 59.3% and T. aggressivum by 59.1% on 4,000 ppm. But mixing compounds which are made from P. menziesii and C. obtusa extracts by variety ratio had lower antifungal activities than original extracts. Main antifungal active components of P. menziesii extracts against Tricholderma genus were 2-Isopropoxy-ethylamine 46.5%, epifluorohydrin 8.6%, trans-2,3-Di-methyloxirane 7.6%, (IR)-(-)-Myrtenal 6.0%, 2-Methoxy-4-Vinylphenol 3.9% and benzaldehyde 2.8%. In case of C. obtusa extracts, they were ${\alpha}$-Terpinenyl acetate 14.9%, Sabinene 10.9%, dl-Limonene 9.6%, ${\alpha}$-Terpinolene 7.5% and ${\alpha}$-Pinene 7.1%. As mentioned above, these results revealed extracts from P. menziesii and C. obtusa of softwood could be used as potential agents to inhibit Trichoderma genus.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.630-634
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• 2009

"Hyedang", a new covered cultivar derived from the crosses between "Suwon300" and "Haganemugi//CI08397/Haganemugi" developed at the Honam Agricultural Research Institute (HARI), NICS, RDA in 2007. The origin of "Hyedang" is "Iksan 407" (SB951033-B-B-B-72). The initial cross was made in 1995 and the selected line showed a high yield and good quality characteristics under yield trial test in 2004. "Iksan407" consistently performed well for three years (2005-2007) from the four locations of regional yield trial (RYT) in Korea and released as "Hyedang". The characteristics of "Hyedang" were the following: rate III growth habit, green leaf and stem, compact spike and with long rough awns. The heading date was April 25 in upland and April 17 in paddy field, which was 2 and 3 days earlier than that of check cultivar, "Olbori". The culm length was 80 cm which was 8 cm shorter than those of check cultivar. It showed spike length of 4.3 cm and 696 spikes per $m^2$, 51 grains per spike, 35.0 g of 1,000 grain weight and 704 g of test weight. It showed stronger winter hardiness and higher resistance to barley yellow mosaic virus (BaYMV) than those with check cultivar. It showed similar protein content and higher whiteness than those of the check cultivar and diastatic power was higher than that of Olbori. The average yield of the pearled grain in the RYT was $4.17ton\;ha^{-1}$ in upland and $4.27ton\;ha^{-1}$ in paddy field, which was 23% and 9% higher than that of the check cultivar, respectively. This cultivar would be suitable for the area above the daily minimum mean temperature of $-8^{\circ}C$ in January in Korean peninsula.

• Food Science and Preservation
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• v.18 no.3
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• pp.366-373
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• 2011

Recent studies suggested that Cheonnyuncho is a significant source of bioactive phenolic compounds, comparable to phytochemicals, including green tea and onion. In this study, the hot-water and 80% ethanolic extracts of Cheonnyuncho were assessed as to their total phenol content, total flavonoids content, antioxidant activity (DPPH radical-scavenging activity and reducing power), and anti-obesity activity. The results showed that the total phenol contents of the hot water extract and the 80% ethanolic extract were $16.52{\pm}3.87$ and $13.44{\pm}0.85$ mg GAE/g, respectively. The total flavonoids content was detected only in the 80% ethanolic extract, however, with a 778.08 ${\mu}g$ catechin equivalents/g content. The DPPH radical-scavenging activity and reducing power of the 80% ethanolic extract from Cheonnyuncho was significantly higher than those of the water extract (p < 0.05). During the adipocyte differentiation, the 80% ethanolic extract of Cheonnyuncho more significantly inhibited lipid accumulation and ROS production than the 3T3-L1 cells that were treated with hot water extract. Furthermore, the 80% ethanolic extract of Cheonnyuncho suppressed the mRNA abundance of the adipogenic transcription factor, $PPAR{\gamma}$ (peroxisome proliferator-activated receptor ${\gamma}$), and its target gene, aP2 (adipocyte protein 2). These results indicate that Cheonnyuncho extracts can inhibit adipogenesis through a mechanism that involves direct down regulation of $PPAR{\gamma}$ gene expression or via modulation of ROS production associated with radical-scavenging activities.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.435-441
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• 2007

Ground-based optical sensing over the crop canopy provides information on the mass of plant body which reflects the light, as well as crop nitrogen content which is closely related to the greenness of plant leaves. This method has the merits of being non-destructive real-time based, and thus can be conveniently used for decision making on application of nitrogen fertilizers for crops standing in fields. In the present study relationships among leaf nitrogen content of rice canopy, crop growth status, and Normalized Difference Vegetation Index (NDVI) values were investigated. We measured Green normalized difference vegetation index($gNDVI=({\rho}0.80{\mu}m-{\rho}0.55{\mu}m)/({\rho}0.80{\mu}m+{\rho}0.55{\mu}m)$) and NDVI($({\rho}0.80{\mu}m-{\rho}0.68{\mu}m)/({\rho}0.80{\mu}m+{\rho}0.68{\mu}m)$) were measured by using two different active sensors (Greenseeker, NTech Inc. USA). The study was conducted in the years 2005-06 during the rice growing season at the experimental plots of National Institute of Agricultural Science and Technology located at Suwon, Korea. The experiments carried out with randomized complete block design with the application of four levels of nitrogen fertilizers (0, 70, 100, 130kg N/ha) and same amount of phosphorous and potassium content of the fertilizers. gNDVI and rNDVI increased as growth advanced and reached to maximum values at around early August, G(NDVI) were a decrease in values of observed with the crop maturation. gNDVI values and leaf nitrogen content were highly correlated at early July in 2005 and 2006. On the basis of this finding we attempted to estimate the leaf N contents using gNDVI data obtained in 2005 and 2006. The determination coefficients of the linear model by gNDVI in the years 2005 and 2006 were 0.88 and 0.94, respectively. The measured and estimated leaf N contents using gNDVI values showed good agreement ($R^2=0.86^{***}$). Results from this study show that gNDVI values represent a significant positive correlation with leaf N contents and can be used to estimate leaf N before the panicle formation stage. gNDVI appeared to be a very effective parameter to estimate leaf N content the rice canopy.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.387-393
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• 2021

In this study, finite element analysis was performed to evaluate a method of increasing the fatigue life of the pipe connection structure commonly used in the topside structure of offshore platforms. MSC Patran/Nastran, a commercial analysis program, was used, and the critical structural model was selected from the global analysis. To realize the stress concentration phenomenon according to the load, modeling using 8-node solid elements was implemented. The main loads were considered to be two lateral loads and a tensile load on a diagonal pipe. To check the hotspot stress at the main location, a 0.01 mm dummy shell element was applied. After calculating the main stress at the 0.5-t and 1.5-t locations, the stress generated in the weld was estimated through extrapolation. In some sections, this stress was observed to be below the fatigue life that should be satisfied, and reinforcement was required. For reinforcement, a bracket was added to reduce the stress concentration factor where the fatigue life was insufficient without changing the thickness or diameter of the previously designed pipe. Regarding the tensile load, the stress in the bracket toe increased by 23 %, whereas the stress inside and outside of the pipe, which was a problem, decreased by approximately 8 %. Regarding the flexural load, the stress at the bracket toe increased by 3 %, whereas the stress inside and outside of the pipe, which was also a problem, decreased by approximately 48 %. Owing to the new bracket reinforcement, the stress in the bracket toe increased, but the S-N curve itself was better than that of the pipe joint, so it was not a significant problem. The improvement method of fatigue life is expected to be useful; it can efficiently increase the fatigue life while minimizing changes to the initial design.

• Korean Journal of Remote Sensing
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• v.37 no.6_2
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• pp.1819-1827
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• 2021

Land-use/cover change caused by rapid urbanization in South Korea is one of the concerns in flood risk management because groundwater recharge by precipitation hardly occurs due to an increase in impermeable surfaces in urban areas. This study investigated the hydrologic effects of land-use/cover on groundwater recharge in the Yeonje-gu district of Busan, South Korea. A statistical time series analysis was conducted with temporal variations of precipitation and groundwater level to estimate lag-time based on correlation coefficients calculated from auto-correlation function (ACF), cross-correlation function (CCF), and moving average (MA) at five sites. Landform and land-use/cover within 250 m radius of the monitoring wells(GW01, GW02, GW03, GW04, and GW05) at five sites were identified by land cover and digital map using Arc-GIS software. Long lag-times (CCF: 42-71 days and MA: 148-161 days) were calculated at the sites covered by mainly impermeable surfaces(GW01, GW03, and GW05) while short lag-times(CCF: 4 days and MA: 67 days) were calculated at GW04 consisting of mainly permeable surfaces. The results suggest that lag-time would be one of the good indicators to evaluate the effects of land-use/cover on estimating groundwater recharge. The results of this study also provide guidance on the application of statistical time series analysis to environmentally important issues on creating an urban green space for natural groundwater recharge from precipitation in the city and developing a management plan for hydrological disaster prevention.