• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.293-296
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• 2008

This study was carried to select artichoke (Cynara scolymus L.) varieties that can be cultivated in non-heated greenhouse during winter in Jeju Island in Korea. Artichoke varieties namely, 'Purple Romagna' (Neseed Co.), 'Imperial Star' (Keithley Williams Seed Co.), 'Green Globe' (Park Seed Co.), 'Emerald' (Ferry-morse Seed Co.), 'Italian' (Unknown), and 'Carciofo Di Romagna' (Lortolano), were raised in a plug tray with 72 cells for two months and transplanted in a non-heated greenhouse on October 5, 2004. The first harvesting of 'Emerald' and 'Imperial Star' were the earliest and April 26 and 27, 2005 respectively. Most of the varieties were harvested from early May to June 2005. The number of head per plant was the highest in 'Green Globe' with more than five heads and the lowest were recorded in 'Italian' with one head or less. The weight of heads per plant was more than 228 g in 'Purple Romagna', 'Imperial Star' and 'Green Globe'. The highest yield was in 'Green Globe' with 2,172 kg/10a, followed by 'Imperial Star' with 1,947 kg/10a. Accordingly, it is considered that 'Green Globe' and 'Imperial Star' are adequate for the high-yield cultivation in non-heated greenhouse in Jeju Island. They can be harvested from the April to June when cultivated from the early October of the previous year.

• Korean Journal of Ecology and Environment
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• v.47 no.spc
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• pp.57-65
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• 2014

Spatial and temporal distributions of zooplankton were measured in an oligotrophic pumped storage-type hydroelectric reservoir which was composed of two reservoirs exchanging water daily, with water going up at night and going down during the day. Repetitive diel disturbance of the water column can be a unique feature of this reservoir system. Chl-${\alpha}$ concentration was highest in the early winter season. Phytoplankton density was lower in summer monsoon due to high flushing rate on rainy days. The zooplankton density was higher in the smaller upper reservoir possibly due to lower fish density in the upper reservoir. In the seasonal variation a time gap was observed between the phytoplankton bloom and the zooplankton bloom (particularly a rotifer, Keratella cochlearis). It is likely to that Keratella production is partially supported by heterotrophic food sources than phytoplankton. The dominance of a mixotrophic dinoflagellate (Peridinium bipes f. ocultatum) might have complicated the trophic relationship between phytoplankton and zooplankton. Our results provide some ecological information of zooplankton community in a highly disturbed alpine reservoir ecosystem relying on mostly allochthonous organic matter.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.785-789
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• 2021

Paprika productivity is different even in the same quality greenhouse and in the same region. These differences are known to due to differences in various environmental factors. This study was conducted to investigate the difference in the level of various environmental factors between high-productivity (HPF) and low-productivity (LPF) greenhouses. The largest difference between the two greenhouses in the daily or weekly average values of major environmental factors was the CO₂ concentration, but the LPF was higher than the HPF, so it was not determined as a factor for the difference in productivity. Correlation analysis among 14 environmental factors showed a high correlation among irradiation or related factors in moisture. The regression coefficients of the linear regression model between vapor pressure deficit and relative humidity were -0.0202kpa in HPF and -0.0262kpa in LPF. In particular, in February and March, the vapor pressure deficit in LPF was 1.5kpa or more, and the cumulative vapor pressure deficit compared to the cumulative irradiation at the early period of cultivation increased rapidly. The reason for the low productivity in LPF is thought to be that the plant was affected by moisture stress due to high vapor pressure deficit and transpiration under low irradiation conditions in the early period of cultivation and in winter.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.76-82
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• 1978

This experiment was carried out to select adaptable winter wheat varieties to deep seeding for developing early maturing, cold tolerant, and high yielding varieties. Varieties adaptable to deep seeding had deep crown and cold tolerant or early maturing characteristics. Varieties which had deep crown at 6cm seeding depth were Namkwang, Wonkwang, Suweon #202, Milyang #5, Milyang #7, Kitagamigomugi, Norin # 4, J ukoku # 81, Sage, Blueboy, Expection, Oasis, C.I. 14034, Rossalka, Benhur, Biserka, Martonvasar-1, and Martonvasar-2.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.326-336
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• 2023

Growth and seed productivity of black soybean (cv. Cheongja-3ho) sown on four different dates were investigated in paddy fields in the southern region to cope with climate change, trends in consumption of soy foods, and the spread of double cropping region. Sowing date of black soybean showed a significant correlation with above-ground growth, seed yield, useful components, etc. When sown in May, the above-ground part was plentiful, while seed yield significantly decreased. On the other hand, when sown in June and July, reproductive growth was vigorous resulting in high seed yield, exceeding 200 kg/10a, and pod injury and seed coat cracking were reduced. Furtherm ore, the isoflavone content of seed increased significantly as the sowing date was delayed. These results suggests that sowing from early June to early July is appropriate. Nevertheless, late June sowing oppears the m ost appropriate for black soybeans in the southern paddy fields, in order to avoid a risk of overlapping with sowing dates of winter crops in the double cropping.

• Korean Journal of Ecology and Environment
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• v.57 no.2
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• pp.61-74
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• 2024

Daemadeung, located in the estuary of the Nakdong River, is formed by sand dunes and possesses well-developed intertidal flats. This study aimed to investigate the habitat of benthic microalgae, photosynthetic pigments, and photosynthetic efficiency in the intertidal flats of Daemadeung from January to December 2011. The inorganic nitrogen content in the sediment pore water was primarily composed of ammonium, while nitrate + nitrite was dominant in the upper layer water. The concentration of chlorophyll a and fucoxanthin in the sediment surface was significantly higher than the mean of all the sediment layer. The average Fv/Fm of benthic microalgae during the entire survey period was 0.52±0.03, with the highest value (0.61±0.08) observed in February. The rETR_max showed a seasonal trend, being high from spring to early autumn (April to October) and low from winter to early spring (January to March, November, December), with the highest value (153.05±2.30 µmol electrons m^-2 s^-1) in July and the lowest (38.49±5.17 µmol electrons m^-2 s^-1) in January. The average Fv/Fm of diurnal microalgae was 0.48±0.03, with the highest value (0.61±0.08) observed at noon. The rETR_max showed a highest peak at noon (54.24±11.35 µmol electrons m^-2 s^-1) and reached its lowest point at 16:00 (26.17±4.75 µmol electrons m^-2 s^-1). These findings suggest that the productivity of benthic microalgae varies significantly depending on the survey time and sediment depth. Therefore, to quantify the productivity of benthic microalgae using Diving-PAM, surveys should be conducted based on tidal conditions, and simultaneous pigment analysis of sediment layers should also be performed.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.1
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• pp.31-36
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• 1978

A field experiment was conducted on a recently reclaimed hillside land to investigate the effectiveness of newly formulated compound fertilizer (10-14-11) containing fused phosphate as phosphorus source. Winter barley was adopted as a crop and commercial compound fertilizer (22-22-11), triple superphosphate, and ordinary fused phosphate were compared with the new compound fertilizer. The result of present study is summarized as follows. 1. When viewed from the plant hight and dry matter yield observed at different growth stages, it was indicated that newly formulated compound fertilizer seemed to be more effective in late stage than early stage. 2. Grain yields were higher in the compound fertilizer plots compared to the triple superphosphate and fused phosphate plots. The yield was specially high in the newly formulated compound fertilizer plot. In this plot, the number of grain per panicle and the rate of maturity were higher than the other plots. 3. The amount of phosphorus uptake by plant in the newly formulated compound fertilizer was lower in early stage and higher in late stage. In this experiment, the magnesium and silica contained in fused phosphate did not influence the growth and yield of barley because the soil was relatively high in these components. 4. Because of the unprecedented severity of winter weather during the experiment, the result obtained in present study may not be generalized until some studies confirm present findings.

• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.4
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• pp.245-251
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• 2013

These experiments are being conducted to obtain data of plant height, panicle length, heading date, number of culm, and fresh and dry weight, crude protein, acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrients (TDN) by six times seeding of 10 days interval ranging from May 1st to June 21st for two types of barnyard millet from the Suwon area in Korea. In the early-heading type, IT 170609 (Echinochloa crus-galli), the plant height and the number of culm per square meters are decreased by late seeding relatively, and heading date is 7 to 10 days earlier than the late seeding. And the dry weight of forage is rapidly decreased after the June 11th seeding. In the late-heading type, IT 195422 (Echinochloa frumentacea), the plant height and the number of culm per square meters are also decreased by late seeding relatively, and heading date is about 13 days earlier than late seeding. The dry weight of forage was rapidly decreased after the June 11th seeding. In both two types, the nutritive value of ADF, NDF, and TDN are not changed by late seeding, but crude protein is increased by late seeding. The TDN yields of late-heading type, IT 195400, show average amounts in the June 1st seeding, but the TDN yield of early-heading type, IT 170606, indicate safety amounts of dry weight to the March 21st seeding. And these data are available for cropping systems, cultivating barnyard millet in summer and cereals for forage in winter, to get high production of forage in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.311-322
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• 2019

In order to establish an optimal double cropping system to obtain the maximum annual quantity, we investigated the annual productivity of whole-crop silage (WCS) rice, Jowoo (Jw), Yeongwoo (Yw), and Mogwoo (Mw), and winter feed crops (WFC), Italian ryegrass (IRG), Greenfarm (GF), rye Gogu (GU), and triticale Joseong (JS), in paddy fields of the central plains of Korea. From 2016 to 2019, each crop was subjected to two standard cultivation methods: WCS rice and WFC optimal. Using the WCS optimal mode, the average dry matter yield (DMY) of WCS rice, early flowering Jw, was 15.8 tons/ha and 21.0 for the mid-late heading Yw; there was no significant difference compared to the 19.2 tons/ha late-flowering Mw (p<0.01). The WFC were not significantly different between GF (3.2 tons/ha) and GU (4.5) sown on September 23rd, while JS was the highest at 12.6 tons/ha (p<0.001). There was a significant difference in the order of JS (16.6 tons/ha) > GF (10.5) > GU (4.7)(p<0.001) sown on October 11th. For JS sown on October 31st, the DMY was 11.8 tons/ha, which was significantly higher than that of the other two crops (p<0.05). Except for rye GU, DMY was the highest when sown on October 11th. For WFC optimal mode, the average DMY of JS was the highest at 18.3 tons/ha, which was significantly different from that of GF (10.9) and GU (9.6) (p<0.001). The DMY of WCS rice transplanted on May 10th was the highest at 23.0 tons/ha in Mw, which was not significantly different from that of Yw (21.4) but significantly different from that of Jw (15.9) (p<0.05). On transplanting on May 25th, the DMY of Mw was the highest at 24.2 tons/ha; this was not significantly different from that of Yw (20.7), but it was significantly different from that of Jw (18.6) (p<0.05). When transplanted on June 11th, the DMY was 21.3 tons/ha in Yw, which was significantly higher than the DMY of other two cultivars, Jw and Mw (p<0.05). For the WCS rice-WFC double cropping, the total annual DMY was 33.6 tons/ha with the combination of the WCS rice, Yw, and the triticale JS for WCS optimal mode. Meanwhile, the total annual DMY was 39.6 tons/ha with the combination of the triticale JS and the WCS rice, Yw, for WFC optimal mode. In conclusion, the strategies for obtaining the maximum yield of high-quality forage for WCS rice-WFC, WFC-WCS rice double cropping are as follows: 1) cultivation centered on the optimal mode of WFC, and 2) sowing the WFC, triticale JS in mid-October, harvesting the crops around the end of May and transplanting the WCS rice, Yw, in early June to obtain the maximum DMY of 39.6 tons/ha.

• 한국해양학회지
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• v.23 no.4
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• pp.194-206
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• 1989

Seasonal variations of nutrients (ammonium, nitrite, nitrate, phosphate and silicate), primary productivity and ammonium regeneration rate of macrozooplankton were investigate to understand the relationship between nitrogen recycling and nitrogen requirement by phytoplankton from Feburuary 1986 to November 1987 in the Kyunggi Bay, shallow estuarine water of Yellow Sea. In general, nutrients increased during the winter and depleted during the spring and the early summer except temporally sharp increase after flood in September. Ammonium was prevalently generally found in high concentration throughout the study area and it occasionally raised N/P ratio in the range of 30 to 70 as in the freshwater environment. Daily net primary productivity ranged from 30.3 to 3580.0 mgC/$m^2$/d with an average of 883.9 mgC/$m^2$/d. Annual primary productivity was determined to be 320.0 gC/$m^2$/yr. Carbon assimilation number ranged from 2.9 to 19.4 mgC/mg chl-a/h which increased in the summer and decreased in the winter. Nitrogen requirement by phytoplankton ranged from 0.4 to 45.0 mg at-N/$m^2$/d and turnover time of inorganic nitrogen ranged from 2.4 in the late summer to 122.7 days in the winter. Nitrogen regeneration rate of mixed macrozooplankton determined by bottle incubation method ranged from 0.02 to 1.34 mg at-N $m^2$/d and it could contribute from 2.8 to 38.7% with an annual average of 14.9% of total nitrogen requirement by phytoplankton in this shallow estuarine environment.