• Title/Summary/Keyword: Hydroponics

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Studies on the optimum cultivar for hydroponics ad the optimum hydroponic system of cherry tomatoes (수경재배에 적합한 방울토마토 품종선발 및 적정수경방식 개발에 관한 연구)

  • 김영식
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 1992.12a
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    • pp.19-20
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    • 1992
  • salad, desert용으로 수요가 급속히 증가하고 있는 방울토마토를 대상으로, 국내품종과 우리나라에서 지배되고 있는 일본품종중 수경재배방식에 적합한 방울토마토 품종을 선발하고, 또한 우리나라에 적합한 수경재배방식을 개발하는 것을 실험목적으로 한다. (중략)

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Development of the Measuring System for Automation of Hydroponics (수경재배 자동화를 위한 계측시스템의 개발)

  • 김성은;김영식;김승우
    • Journal of Bio-Environment Control
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    • v.5 no.2
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    • pp.210-214
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    • 1996
  • The measuring system was developed for automation of hydroponic culture. It runs in Windows 3.1 and 95. Main window contains greenhouse screen and menu bars such as system setting, sensor calibration, greenhouse status, actuator control, file management, view, and help. Users can use pop-up menu, tool bar and status bat as well as menu bar for manipulation. Especially it was designed to retain flexibility for researchers, who changed detecting sensors frequently. Users can change storage intervals of files, of which 3 types were prepared to use in other software like as statistical programs, graphic programs and/or spread sheets. This system was adopted to deep flow culture system and evaluated to be appropriate for any kind of hydroponic systems.

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Development of a Supporting System for Nutrient Solution Management in Hydroponics I. Fertilizer Combination and Electrical Conductivity(EC) Prediction (양액재배를 위한 배양액관리 지원시스템의 개발 I. 배양액의 배합 및 전기전도도(EC)의 예측)

  • 손정익;김문기
    • Journal of Bio-Environment Control
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    • v.1 no.1
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    • pp.52-60
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    • 1992
  • The optimum management of nutrient solution needs the effective combination of fertilizers as well as the accurate control of nutrient solution. This study was attempt to make a supporting system for effective fertilizer combination by using computer and also to develop a EC predicting equation for keeping the EC of solution within the allowable range after application of combined fertilizers. The supporting system consists of three parts : (1) data bases, (2) rules for deciding the kinds and amounts of fertilizers and (3) main control. With input data, the main control automatically constructs the network connecting the related data bases and subsequently executes the operation of searching proper fertilizers through it. For more effective searching, fertilizers are classified into two levels(level 1 and level 2) in consideration of solubility, price, and frequency in use, and searched in that order. The EC prediction equation, a extended form of the Robinson and Stroke's theoretical equation only available for a binary electrolyte, is suggested for predicting the EC of the nutrient solution containing many kinds of inorganic compounds. The comparison of predicted and measured ECs showed good agreements with the high correlation between the predicted EC decrement by ion interaction and the actual one(limiting EC minus measured EC).

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Effect of Potassium Phosphonate on the Control of Phytophthora Root Rot of Lettuce in Hydroponics

  • Jee, Hyeong-Jin;Cho, Weon-Dae;Kim, Choong-Hoe
    • The Plant Pathology Journal
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    • v.18 no.3
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    • pp.142-146
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    • 2002
  • The effect of potassium phosphonate ($KH_2PO_3 or $K_2 HPO_3$) on the control of Phytophthora root rot of lettuce was evaluated in a liquid hydroponic culture. Phosphonate 100 ppm strongly inhibited mycelial growth of Phytophthora species in vitro but did not affect normal growth of lettuce in a greenhouse test. Application of the chemical before infection showed over 94% control value, while it was less than 35% when applied after infection. In a field trial, phosphonate 100 ppm, which was directly supplemented into the nutrient solution, satisfactorily controlled the disease as it did not develop until 28 days after transplanting and remained at less than 2% infection rate at the end of cultivation. Meanwhile, in the control plot, the disease initiated at 7 days after transplanting and developed rapidly reaching over 70% infection rate at 28 days. Population density of the causal pathogen, R drechsleri, in a heavily infested farm was 22.0-25.0 cfu/100 ml of nutrient solution. However, it decreased to 1.3-2.0 cfu/100 ml at 7 days after treatment with phosphonate 200 ppm.

Non-Destructive Estimation of External Quality of Cherry Tomato Fruits by Hydroponics (방울토마토의 수경재배시 외형형질의 비파괴적 추정)

  • 김영식
    • Journal of Bio-Environment Control
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    • v.3 no.1
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    • pp.52-57
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    • 1994
  • The external qualities of cherry tomato fruits(Lycopersicon esculentum) grown in circulating deep flow hydroponic culture were non - destructively estimated in 1992 under warm climate conditions and evaluated in 1993-1994 under cool season. The fruit size of ‘Minicarol’ was by far the smallest compared to ‘Chelseamini’ and ‘Popo’. There were high correlations between external qualities of fruits-lengthwise growth harmonized with widthwise growth. The volume and/or weight of fruit could be non -destructively estimated by length and width of fruit. Volume=0.071$\times$ (length+width)$^3$+0.451, Fresh weight=0.072$\times$ (length+width)$^3$+0.542. These models were accurately evaluated by fruits harvested in 1994.

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