• Korean Journal of Ecology and Environment
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• v.47 no.spc
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• pp.48-56
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• 2014

Weekly changes of water environments and phytoplankton community with the salinity gradients were investigated at Gyoungpo Lake from April to November in 1998 and 2012. Underwater crossam in Gyoungpo Lake was removed in 2004. Thereafter, average salinity of Gyoungpo lake increased from 7.5 ppt in 1998 to 20 ppt in 2012. A total of 99 and 80 species of phytoplankton was observed from the sampled in 1998 and 2012, respectively. The number of common species during the 2 separate years was 40. Transparency, SS, $NO_3-N$ concentration and N/P ratio in 2012 were lower than those in 1998. During the period of water shortage (April, May) of 2012 transparency decreased due to decreased salinity and increased SS and Chl. a. Correlation coefficients between species and community scores of DCA ordination based on data matrix of the phytoplankton revealed larger variation among sampling seasons in 1998 than in 2012. The increase of seawater influx and conversion rates following the removal of the underwater crossbeam might explain such a differential variation. Gymnodium sp., Peridinium sp., Prorocentrum sp., Nitzschia longissima, Schroederia setigera, Lyngbya sp., Asterococcus limneticus, Asterococcus superbus and Cyclotella meneghiniana were found to well adapt at the high salinities in 2012. Comparatively, Asterrionella formosa, Nitzschia frustulum, Chlorella ellipsoidea, Scenedesmus bijuga and Scenedesmus ellipsoideus were observed at lower salinities in 1998. Two quite contrasting phytoplankton communities were found in the two seasons of a year, spring with limited precipitation and summer, the flood season.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.26-32
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• 2004

Growth and yield of cucumber (Cucumis sativus L.) with arch training method were evaluated on several training heights, planting densities, and topping node orders. Cucumber cultivar 'Eunsung-baekdadagi' was planted on 9 June with three training heights of 1.5, 1.8, and 2.1 m, there planting densities of 90${\times}$40, 90${\times}$50, and 90${\times}$60 cm, and five topping node orders of 20th, 30th, 35th, and nontopping. The plot of 2.1 m training height resulted in the higher sun-scald fruit rates due to the higher temperature above 37$^{\circ}C$ in the upper space of plastic house. The plot of 1.8 m arch training height showed higher fruit setting and marketable yield rate compared to the other training heights. The maketable yield rate with 1.8 m height arch training was 102,691 kg ${\cdot}$ $ha^{-1}$, 21% higher value than that of 1.5 m. Powdery mildew incidence increased with the increase of planting density. Lower LAI were shown depending on the higher topping node order. Lower light transmission ratio was shown in the higher planting density plots, might be due to the crowded stems and leaves inside those plots. Fruit setting rate was also higher in main stems rather than in lateral ones. Marketable yie이 in 90${\times}$50 cm planting distance with 35th node topping treatment was 98,311 kg ${\cdot}$ $ha^{-1}$, 5% higher than that 90${\times}$40 cm planting distance with 30th node topping treatment. Thus the 1.8 m of training height, 90${\times}$50 cm of planting distance, and 35th node topping was evaluated for the effective cultivation condition in arch training of cucumber in highland.

• FLOWER RESEARCH JOURNAL
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• v.16 no.4
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• pp.299-303
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• 2008

An Oriental lily cultivar 'Pacific Wave' was released in 2007 at National Institute of Horticultural and Herbal Science, Rural Development Administration (RDA), Suwon, Korea. The crossing was made in 1999 between Oriental lily 'Simplon', an outward-facing and white colored cultivar, and 'Spinoza', pink colored cultivar. The first selection was done in 2003 with a line of 'O-03-16'. Multiplication and bulb growth, and performance test was conducted from 2004 to 2006. This selection was later on given as 'Pacific Wave' in 2007 at NHRI. Flowering time of 'Pacific Wave' in plastics house culture is mid June and grows average 115 cm. Flowers are upward-facing with 20.1 cm in diameter and white with yellow centered (RHS W155C + Y9A). Mean petal length and width is 12.2 cm and 4.2 cm, respectively. Leaves are 12.3 cm long, 2.9 cm wide. The throat color is green. It shows gray and purple stigma, and red brown pollen. The weight and size of bulb is 82.5 g and 19.6 cm, respectively. Year-round flowering can be by storing the bulb under -1 to $-2^{\circ}C$ conditions. It is necessary to add calcium to the fertilizer or remove side scales to prevent leaf scorch. It is needed to control Botrytis disease in summer wet season.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.323-334
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• 2007

We analyzed the ocean environmental data from water sample and automatic measurement instruments with the Incheon-Jeju passenger ship for 18 times during 4 years from 2001 to 2004. The objectives of this study are to monitor the spatial and temporal variations of ocean environmental parameters in coastal waters of the Yellow Sea using water sample analysis, and to compare and analyze the reliability of automatic measurement sensors for chlorophyll and turbidity using in situ measurements. The chlorophyll concentration showed the ranges between 0.1 to $6.0mg/m^3$. High concentrations occurred in the Gyeonggi Bay through all the cruises. The maximum value of chlorophyll concentration was $16.5mg/m^3$ in this area during September 2004. The absorption coefficients of dissolve organic matter at 400 nm showed below $0.5m^{-1}$ except those in August 2001 During 2002-2003, it did not distinctly change the seasonal variations with the ranges 0.1 to $0.4m^{-1}$. In the case of suspended sediment (SS) concentration, most of the area showed below $20g/m^3$ through all seasons except the Gyeonggi Bay and around Mokpo area. In general SS concentration of autumn and winter season was higher than that of summer. The central area of the Yellow Sea appeared to have lower value $10g/m^3$. The YSI fluorometer for chlorophyll concentration had a very low reliability and turbidity sensor had a $R^2$ value of 0.77 through the 4 times measurements comparing with water sampling method. For the automatic measurement using instruments for chlorphlyll and suspended sediment concentration, McVan and Choses sensor was greater than YSI multisensor. The SeaWiFS SS distribution map was well spatially matched with in situ measurement, however, there was a little difference in quantitative concentration.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.3
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• pp.154-162
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• 2003

This study was conducted to investigate the effects of tile drain on Physicochemical properties and crop productivity of soils under plastic film house for three years (1999 - 2001). Tiles (${\Phi}100mm$ PVC pipe) were established at 50-60 cm depth with 1 m, 2 m, and 3 m intervals in Gangseo silt loam soil under 2W-type plastic film house. Cropping system was a pumpkin-pumpkin in the first year, a cucumber-spinach-crown daisy-spinach-young radish in the second year, and a green red pepper-tomato-spinach in last year, with conventional fertilization and drip or furrow irrigation by groundwater pumping. Bulk density and soil hardness of plot with tile drain were lower than those of control (plot without tile drain). Soil water content was also lower in tile drain plot than in control regardless of soil depth, and decreased at narrower interval and longer distance from tile in the same plot, thus suggesting that water flow and density of tile drain plot was higher than those of control. Rhizosphere of spinach, a final crop of third year, was expanded more than 2 cm due probably to improvement of soil physical properties caused by tiles establishment. Electrical conductivity (EC) of topsoil decreased from $1.22dS\;m^{-1}$ to $0.82dS\;m^{-1}$ by tile drain system, and the extent of EC decrease was different with season: higher in spring and lower in summer and autumn. The $NO_{3^-}-N$ concentration in topsoil decreased, from $200mg\;kg^{-1}$ to $39mg\;kg^{-1}$. The effect of tile drain on crop yield varied with crops. Average crop productivity obtained in tile drain plot than that of control crop: 18.2% in 2 m interval, 14.2% in 3 m interval, but lower 0.2% in 1 m interval.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.667-673
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• 2011

There is relatively high vulnerability of soil erosion in slope highland agriculture due to a reclamation of mountain as well as low surface covering in early summer season with high rainfall intensity time. The aim of this study was to evaluate various surface covering methods for reducing soil loss in highland radish cultivation in highland. The experiment was conducted in 17% sloped lysimeter ($2.5m{\times}13.4m$) with 8 treatments including covering with cut rye, sod culture of rye, Ligularia fischeri var. spiciformis Nakai, Arachniodes aristata Tindale, Aster koraiensis Nakai, Festuca myuros L. and mulching with black polyethylene film, and runoff water, eroded soil and radish growth were investigated. Surface covering with sod culture and plant residue, especially cut rye treatment, had lower runoff water than non-covering, whereas black polyethylene film mulching had the reverse. The amount of eroded soil was also lowest in cut rye treatment, $0.3Mg\;ha^{-1}$, and increased in the order of rye sod culture, Ligularia fischeri var. spiciformis Nakai, Aster koraiensis Nakai, Festuca myuros L., Arachniodes aristata Tindale, black polyethylene film, and non-covering, $68.2Mg\;ha^{-1}$. The results showed that surface covering with sod culture or plant residue could be effective for reducing runoff water and soil erosion in the radish field, significantly in cut rye treatment. On the other hand, in sod culture of rye, Aster koraiensis Nakai and Ligularia fischeri var. spiciformis Nakai, radish yields were lower than in the non-covering. Unlike this, covering with cut rye, sod culture of Festuca myuros L. had similar radish yield to the non-covering radish yield. In conclusion, covering with cut rye and sod culture of Festuca myuros L. were beneficial for reduction of soil loss without decreasing in radish yield in highland sloped fields.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.3
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• pp.256-264
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• 2021

Rapeseed (Brassica napus L.) is generally sown in late autumn and harvested in early summer in Korea, however, spring cultivation has also been attempted in some areas because frequent climate changes induce reducing productivity. Therefore, there is a need for a transplanting technology that is relatively easy to control of cropping season according to changes in cultivation conditions. In this study, to find out the optimal characteristics of seedlings for machine transplanting of spring cultivation, seedling morphological characteristics were investigated according to the seedling age of three varieties for 2020 and 2021. The hypocotyl length was less than 2 cm in both years and the 40-day-old seedling was the shortest among all seedling ages. The number and size of leaf were increased with longer seedling age in both years. To evaluate seedling quality, total seedling length, seedling weight, and impact resistance were measured before transplanting. Total seedling length was the longest in 40-day-old seedlings and the shortest in 25-day-old seedlings in both years. In the case of seedling weight, no significant differences were observed depending on the seedling age and the impact resistance increased with increasing seedling age. Finally, 'Jungmo7001', 'Naehan', and 'Tamla' showed a high transplanting rate in seedlings grown for more than 30 days, 35 days, and 40 days, respectively, in the field using a general transplanter. These results suggest that the proper seedling age for transplanting is limited depending on the rapeseed varieties. The suitable seedling cultivation method can be selected for different cultivation environments.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.335-341
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• 2021

In this study, experiments were conducted to investigate the effects of high- temperature stress on paprika in a semi-closed greenhouse where cooling is available and a normal plastic greenhouse. Paprika grown in a semi-closed greenhouse in which geothermal cooling is provided showed a significantly higher speed of photosynthesis than paprika grown in a 3-layer plastic greenhouse in which there is no cooling system. It suggests that the photosynthesis speed of paprika in a plastic house decreases owing to high temperature stress. Plant height increased by 13cm more in the semi-closed greenhouse, and the size of leaf showed similar growth speed until the 2nd week after transplanting, however, after 3 weeks, the semi-closed greenhouse showed a big difference by 47% compared with the plastic greenhouse. In terms of the fruit count, the semi-closed greenhouse had 10.6 fruits/plant and the plastic greenhouse had 4.6 fruits/plant, indicating that the semi-closed greenhouse had a higher number of fruits by 130% than the plastic greenhouse. The fruit weight also presented a difference between the semi-closed greenhouse and the plastic greenhouse by 46%, which is 566.7g/plant and 387g/plant, respectively. According to the above mentioned results, it was validated that when paprika is cultivated in a semi-closed greenhouse where a cooling system is applied, photosynthesis and growth were better than in the normal plastic greenhouse. Thus, if the hot summer season is overcome by applying the elemental technologies for the cooling system to the normal plastic greenhouse, farm income may increase through improvement in the yield and quality.

• Korean Journal of Breeding Science
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• v.43 no.6
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• pp.576-580
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• 2011

'Keunseom', a new second generation Tongil-type rice variety (Oryza sativa L.), is a mid-maturing ecotype developed by the rice breeding team of Department of Functional Crop, NICS, RDA in 2006. This variety was originated from a cross between 'Dasanbyeo' and 'Namyeongbyeo' in 1996's summer season, which developed by pedigree breeding method. The pedigree of 'Keunseom' was YR18234-B-B-98-3-5-1, and it was designated 'Milyang202' in 2002. 'Keunseom' has tolerance to lodging, because it has short culm length as 77 cm. This variety is resistance to bacterial blight K1 race, rice stripe virus, rice dwarf virus, and leaf blast disease. Milled rice kernel of 'Keunseom' is a clean translucent with non-glutinous endosperm, and has good quality as it was clear in chalkness. The milled rice yield potential of 'Keunseom' was about 719 kg/10a at ordinary fertilizer level of local adaptability test. This cultivar would be adaptable to the mid and southern plain of Republic of Korea.

• Journal of Bio-Environment Control
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• v.28 no.3
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• pp.234-242
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• 2019

We analyzed the anthocyanin accumulation, abscisic acid (ABA), gibberellic acid (GA) contents and metabolic genes expression in berry skins under high temperature (High T) at veraison, in order to investigate the cause of bad coloration of 'Kyoho' grape due to High T in summer season. The coloration of 'Kyoho' grapes was stopped by High T for 10 days from veraison, and the fruit quality was not affected except skin color. Total anthocyanin of skins was decreased by High T treatment and malvidin and peonidin were decreased compared to control. In berry skins, ABA content did not decrease by High T treatment, but it was rather higher than that of control. GA content was increased about two times compared to the control after 10 days of High T treatment, which caused decreased ratio of ABA/GA. Analysis of expression of anthocyanin biosynthetic genes showed that the early biosynthetic genes were not affected by High T and the expression of UFGT was decreased by temperature treatment. ABA biosynthetic gene expressions were not affected by High T and the expression of GA20ox1 and GA2ox1/2, which are known to regulate the biosynthesis and inactivation of GA, were increased and decreased by High T, respectively. Therefore, the bad coloration of 'Kyoho' grapes under the High T at veraison was due to inhibition of anthocyanin biosynthesis of skin, and it was suggested that the anthocyanin biosynthesis was controlled by the ratio of ABA and GA rather than ABA content.