• Journal of Bio-Environment Control
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• v.26 no.1
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• pp.7-12
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• 2017

This experiment was conducted to analyze the effect of drainage reuse rate on the growth and fruiting of summer paprika in closed hydroponic cultivation. The experiment was carried out for 25 weeks from March to September 2015 with 0, 20, 30, 50% mixing ratio of waste nutrient solution using non - recycling hydroponic cultivation as a control. As a result, stem diameter of the test was different in the groups 1 and 2, but no difference showed as the group progressed more than 3 groups. L.A.I tended to decrease with increasing drainage mixing ratio. The number of nodes in the 50% reuse test group was 1.4 compared to the control group, but there was no significant difference. The number of harvested nodes was significantly different in the control group (11.1 nodes) and the 50% reuse test group (8.7 nodes), and the harvested nodes tended to decrease as the drainage was reused. The ratio of harvest was also the same as that of the harvesting node, and the control was the highest at 33.2% and the lowest at the 50% reuse test at 27.6%. Relative yields were reduced by 30%, 35% and 45% in the control group in the first group, and this tendency was also observed in the second and fourth groups. However, in the 3 and 5 groups, the production of 50% test group increased by 13% and 5%. The ratio of unmarketable fruit was increased 2%, 4%, 4%, and 7% in 0%, 20%, 30% and 50% reuse test, respectively. In conclusion, if the decrease in yield due to the decline in early growth is carefully managed, even if the imbalance of inorganic ions occurs after the mid-term growth, the growth of the crop will enter into a stable period and the re-use will not be worried about the growth and the yield decrease.

• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.100-107
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• 2017

This experiment was carried out to analyze the effects of substrate reuse on the growth and yield of summer paprika in cyclic hydroponics. The test group was divided into a new coco slab, one year reused coco slab two year reused coco slab based on 30% nutrient solution reuse, and was performed from April 18 to November 31, 2016 for 30 weeks. As a result, plant height of early growth was that the 2 year reused slab was longer than the new slab but the final growth period was 56.58 cm shorter. First group flower position was that reused slab was shorter by 2.92 cm than the new slab and the second group flower position was 0.31 cm long. The relative internode length of early growth, when the reused slab was used, the imbalance in the late growth stage was increased compared with the use of the new slab. The number of growth nodes in the 1 and 2 year reused slab was the smallest with 27.4 nodes. However, the number of harvested nodes did not show the difference in the test group, and the ratio of harvested that the 2 year reused slab was the highest at 26.8%. The ratio of unmarketable fruit tended to increase as the growth progressed. Fresh weight was 227.7g for new slab, 219.2g for 2 year reused slab and 21.2g for 1 year reused slab. The dry weight of the new slab increased with the reuse of the slab. It was 17.13g for new slab, 18.26g for 1 year reused, and 19.28g for 2 year reused. The average water content of the entire growth period was smaller as the slab was reused, and the 1 year reused slab was about 20g less than the 2 year reused slab. This trend was steadily occurring throughout the entire growing season. Especially, the reused slab for 1 year was less than 60g after 3 groups compared to other test groups. In conclusion, If will control seriously occurrence of unmarketable fruits by weakening after medium growth in summer-cultivated paprika in EC-based recycling hydroponic cultivation with reused cocopeat substrate, It is not what I have to worry that decrease of the yield and deterioration of the quality due to the change of physical and chemical properties of the slab and the pathogenic bacteria infection.

• Journal of Bio-Environment Control
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• v.30 no.3
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• pp.230-236
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• 2021

Changes in greenhouse temperature and solar radiation due to fogging and shading were monitored during hydroponics in high temperature in summer season. Experiment 1 consists of four treatments, namely, Control, Shading, Fogging, and Fogging + Shading based on sunny days August. For Experiment 2, two melon cultivars of 'Dalgona' and 'Sopoong gaza' were cultivated in summer of 2020 using Fogging + Shading with the best result for temperature reduction effect from Experiment 1. As a result of Experiment 1, the effect of Fogging + Shading on temperature reduction was apparent where the inside was about 4℃ (as the lowest temperature) lower than the outside. Fogging + Shading showed the inside was 2-4℃ lower than the outside, and Fogging or Shading treatments had little difference, compared to the Control where the internal temperature of greenhouse was 3-4℃ higher than the external. For solar radiation changes between greenhouse inside and outside, the internal change was in a similar pattern between Fogging and Control, and between Shading and Fogging + Shading, respectively. In case of the Fogging treatment (similar with the Control) only the effect of solar radiation reduction as influenced by plastic greenhouse covering materials was examined. The Fogging + Shading had a very similar change in solar radiation to the Shading. Based on these results, Experiment 2 was conducted in summer of 2020 and resulted in a temperature reduction effect of about 3.9℃ according as the inside of air-conditioned greenhouse was kept 32.4℃ when the maximum temperature of the outside reached 36.3℃ in August during the cultivation period. In addition, the quality of melon fruit was good (1.3-1.5 kg of fruit weight, 12.6-13.3 of soluble solids content. In the case of using Fogging + Shading cooling treatment, it can bring about the effect of reducing the temperature during the high temperature in summer, and normal growth of melon and fruit harvesting were possible.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.4
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• pp.254-259
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• 1991

The present study was carried out to investigate the effect of nitrogen(urea) application on the seasonal change in pH content of Bray No.1-P, organic matter, and exchangeable cations along the grassland soil profile and further to provide the fundamental information for optimizing the rate of fertilizer application to grassland. Soil samples were taken 20cm intervals upto 100cm soil depth in spring(May 26), summer(July 27), and autumn (October 18) of 1990. The obtained results are summerized as follow 1. In spring and summer, soil pH at 0-20cm soil depth of 28kg N/10a treatment was lowered by 0.7 and 1.0 in comparison with those the same soil depth of 0 kg N/10a treatment and the tendency in pH decrease during all season at the soil depth below 20cm was in the order of summer>spring>autumn. 2. Although Bray No.1-P content at the soil depth 0-20cm of 28kg N/10a treatment was lowered by 20ppm compared to 0 kg N/10a treatment in summer, there was no great difference in its content between 0kg N/10a and 28kg N/10a treatment at all soil depth in spring and summer. In autumn, its content at soil depth below 20cm of 28kg N/10a treatment was higher than that of in summer. 3. Organic matter content at 0-20cm soil depth of 0 and 28kg N/10a treatment in autumn was slightly lowered and on the whole there was very little change in it by soil depth and nitrogen application. 4. The calcium content of 0 and 28kg N/10a treatment was also slightly lowered by increase in soil depth and Mg and K contents were below 0.4 and 0.2 me/100g during all seasons, respectively. 5. Positive correlations were shown among the $NH_4-N$ content and pH, organic matter, Ca and Mg of 0 kg N/10a treatment, however, there was negative correlation ($r=-0.534^{*}$) between $NO_3-N$ content and pH of 28kg N/10a treatment in summer.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1570-1574
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• 2009

2008년 여름 우리나라는 예년과 달리 홍수기에 북상하는 태풍이나 8월말에서 9월초까지 발생하던 장마전선의 영향을 받지 못했을 뿐만 아니라 홍수기 이후에도 중국에서 다가오는 동서고압대의 지속적인 영향으로 9월 중순 최고기온을 경신하면서, 강수가 없는 건조한 날씨가 계속되었다. 남부지방을 중심으로 8월말 이후 심화된 가뭄은 9월 중순에는 전국적으로 확산되었으며 도서지역의 부분적인 제한급수가 실시되거나 밭 작물 재배에 피해를 초래하기도 하였다. 본 연구에서는 위성영상 기반의 식생지수를 이용하여 2008년 가을가뭄의 시공간적 변화와 행정구역별, 권역별 가뭄 우심지역을 판별하였다. 또한, 가뭄정보를 제공하는 가뭄모니터링 시스템의 가뭄지수와 가뭄의 변화와 심도 등을 비교하였다. 위성영상자료는 MODIS NDVI를 이용하여 제작한 VCI와 SVI를 이용하였으며, 수자원공사의 '가뭄정보시스템'에서 제공하는 주 단위의 가뭄지수와 한국건설기술연구원 '통합수자원평가계획 시스템개발'에서 제공하는 월 단위의 가뭄지수를 활용하였다. 연구결과 행정구역상으로는 전라남 북도와 경상남도 지역이, 권역별로는 섬진 영산강 권역에서 극심한 가뭄이 발생한 것으로 판명되었으며 식생지수 기반의 가뭄발생지역 판별 결과와 기상학적 가뭄지수인 SPI와 PDSI의 가뭄분포가 유사하게 나타났다.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.324-332
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• 2010

This experiment was carrid out to develop a culture method by sequential highland-lowland cultivation for year-round production of fresh leaves in Ligularia stenocephala. Rootstocks of Ligularia stenocephala cultivated in Daegwallyeong openfield were digged up on late October 2007 and then stored in $-2^{\circ}C$ refrigerator. The rootstocks were monthly transplanted in protected greenhouse in Gangneung from November 2007 to June 2008 for lowland cultivation, and also they were monthly transplanted in rainshelter in Daegwallyeong from June to August 2008 for highland cultivation. The early growth of Ligularia stenocephala transplanted on January 2008 was faster. Most plant of Ligularia stenocephala regardless of transplanting time of rootstock grew over 30cm at the time of first harvesting of leaves till May, while the yield decreased during the summer season. The average plant height of Ligularia stenocephala transplanted on July and August in Daegwallyeong highland was lower than that cultivated in Gangneung lowland during spring season. Using of rootstock stored made it possible to produce in highland from Apr. to Oct. during summer season, and also to produce in lowland from Nov. to May next year. Therefore, the results indicates that sequential highland-lowland cutivation by using of stored rootstock will be capable of yearround production of fresh leaves in Ligularia stenocephala.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.388-392
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• 2013

A spray chrysanthemum cultivar 'Green Candy' was released by National Institute of Horticultural & Herbal Science, Rural Development Administration, in 2009. The cross between 'Yoko Ono', a spray chrysanthemum cultivar with light yellowish-green double type, and 'Green Bird', a spray chrysanthemum cultivar with vigorous and green double type, was made in Suwon in 2006. After the evaluation of the characteristics under shade culture in summer and retarding culture in spring and consecutive selection from 2007 to 2009, 'Green Candy' was selected finality. The natural flowering time of 'Green Candy' is October 28th, and it is possible to flower all year-round by shade and light culture. It has double flower type with green petals. The growth of plant is very vigorous and the color of the petals is stable when the variety is cultivated under high temperature conditions in summer season. The diameter of flower is 4.1 cm. The numbers of flower per stem and petals per flower are 12 and 217, respectively. The days for flowering under the short day treatment are about 58 and its vase life is 18.1 days in autumn season. 'Green Candy' was applied as No. 2010-212 on March 5, 2010 for variety protection and the plant variety protection rights have been registered as No. 3633 on August 2, 2011 at the Korea Seed and Variety Service.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.2
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• pp.109-114
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• 2010

This experiment was carried out to know adaptability and forage production and quality of sorghum and sorghum ${\times}$ sudangrass and sudangrass hybrids at paddy field from 2007 to 2008 at Chonnam province. Among growth characters of six Hybrids, 'SX17' hybrid was somewhat strong for waterlogging, and higher sugar content and very good at the 2nd regrowth and disease resistance. Fresh yield of 'SX17' hybrid was the highest as 89,192kg per ha among 6 Sorghum and Sorghum ${\times}$ Sudangrass and Sudangrass hybrids. The dry matter yield of 'SX17' hybrid was also the highest as 21,038 kg per ha. The result of this study showed that 'SX17' hybrid had good growth characters and forage productivity and crude protein (CP) and in vitro dry matter digestibility (IVDMD).

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.346-351
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• 2006

The study was performed to investigate the effect of incorporation of green manures (GM) into a sandy loam soil for organic vegetable production in the condition of plastic film house, relating to growth and yield of tomato crop. Three species of GM as perennial ryegrass, sudangrass and soybean are cultivated during the rest time of summer season and incorporated into soil just after the harvest. Thereafter tomato crop was transplanted as the following crop to soil incorporated GM. Among GM, soybean was proper as GM crop for organic farming, due to the effect of yield increase by continuous supply of nitrogen on following the tomato crop. Yield of tomato crop after soybean incorporation into soil was $4.2Mg\;ha^{-1}$ similar to $4.4Mg\;ha^{-1}$ of N-P-K standard fertilization (conventional) treatment. But perennial ryegrass and sudangrass were improper, because the biomass yield of perennial ryegrass was very low due to growth retardation by high temperature during summer season and soil incorporation of sudangrass as GM results in yield decrease of following the tomato crop caused by high C/N ratio of sudangrass itself. In conclusioa soybean incorporation into soil had advantage of producing conventional level on following the tomato yield and therefore it could recommend as GM for organic vegetable production.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.306-313
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• 2002

The investigation was conducted to find out amounts and ratios of N, P and K fertilizers applied on summer Chinese cabbage in 58 farmers' fields of highland area. The application levels of N, $P_2O_5$, $K_2O$, livestock manure and lime fertilizers were 444, 188, 390, 9,920 and $2,160kg\;ha^{-1}$, respectively, for summer Chinese cabbage. The ratios of basal dressing were 48% in N, 46.6% in $K_2O$. The frequencies of top dressing both N and K were 1.7 times. The kinds of compound fertilizers were in the order of 11-10-10+3+0.3 > 11-6-6+4+13+17 > 12-9-11+3+0.3 in basal application and 18-0-18+0.3 > 13-0-13+1+0.3 > 18-0-15+0.3 in top dressing. From the surveyed results, we could estimate that total 4,347 tons of N, $P_2O_5$, and $K_2O$ fertilizers were over used for summer Chinese cabbage by farmers in highland.