• Journal of Bio-Environment Control
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• v.9 no.3
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• pp.151-155
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• 2000

In order to investigate the optimum irrigation point by soil water tension in oriental melon grown in plastic greenhouse during low temperature season, irrigation points from 10 days before fruiting to 10 days before harvesting were examined with 10, 20, 30 and 50 kPa, respectively. Total amount of water applied was 92.5mm at 10kPa but not irrigated at 50kPa due to the unreach of irrigation point. Fruit weight increased with increased soil water content; it was 456g at 10kPa but 324g at 50kPa. While marketable yield of fruit was lowest at 10 kPa due to increased fermented fruit. Sugar content in fruit was highest at 30 or 50 kPa but lowest at 10kPa. As a result, for higher sugar content and marketable yield, the recommended irrigation point is 30kPa of soil water tension.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.388-398
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• 2020

Watermelon yield mainly depends on soil water content controlled by irrigation in a plastic greenhouse. In this study, we investigated the effect of different soil moisture contents affected by irrigation starting point on growth, yield, and physiological responses of small-sized watermelons. Irrigation was initiated at 5 different levels of soil water content as a starting point with soil moisture detecting sensor after 14 days of transplanting, and stopped at 7 ~ 10 days before harvest. These treatments were compared with the conventional periodic irrigation as control. When soil had the lowest moisture content (-50 kPa), the overall shoot growth was retarded, but the root length and root dry weight increased. The photosynthetic parameters (photosynthetic rate, stomatal conductance, and transpiration rate) of watermelon leaves decreased significantly in the lowest soil moisture content (-50 kPa). On the other hand, the photosynthetic rates of watermelon leaves grown with irrigation starting point between -20 and -40 kPa were observed to be higher than those of other treatments. Fruit set rate and marketable fruit yield increased significantly at -30 kPa and -40 kPa. Proline, abscisic acid (ABA), total phenol and citrulline, which are known to contribute to stress tolerance under drought condition, increased as soil water content decreased, particularly, the largest increases were recorded at -50 kPa. From these results, it was found that an appropriate water supply adjusted with an irrigation starting point between -30 and -40 kPa could help to keep favorable soil water content during the cultivation of small-sized watermelons, promoting the marketable fruit production as well as inducing the vigorous plant growth and reproductive development.

• Journal of Bio-Environment Control
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• v.8 no.4
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• pp.242-249
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• 1999

This study was conducted to investigate the effect of seedling age and irrigation set point on the growth and yield of white spined cucumber cv Sharp-1. Leaf area, number of lateral vines and root weight measured 70 days after planting were the greatest in 30 day-old seedling treatment. Inorganic element content measured 30 days after planting was the greatest in 30 day-old seedling treatment. Total and marketable yields were greater in 30 day-old seedlings than those of 20 or 40 day-old seedlings. The early yield was the least in 20 day-old seedlings. 40-day old seedlings lost vigor quickly. No significant differences in growth and yield observed as affected by irrigation set point.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1996.10a
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• pp.60-63
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• 1996

참외의 시설재배는 초기에 소형 턴넬재배로 부터 시작하여 '95년 현재 전체 재배면적 11,999㏊ 가운데 시설재배가 81.2%인 9,745㏊에 달하여 시설재배가 주류를 이루고 있다. 그러나 그 재배시설은 대부분 단동하우스내에서 소형턴넬을 이용하는 무가온 보은재배형태이기 때문에 환경관리가 부적절한 실정이다. 특히 최근 고당도 신품종보급과 함께 연중 생산ㆍ소비추세의 영향으로 (중략)

• Journal of Bio-Environment Control
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• v.7 no.4
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• pp.330-335
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• 1998

To investigate the effect of soil water control on yield and quality of musk melon in plastic film house, irrigation points were treated with -10, -20, -30, -50 and -100 kPa by 10mm dripping each time at fruit developing and ripening stage, respectively. Fresh weight of stem and leaves was not significant among irrigation points, but percentage of dry matter was highest at -100kPa and lowest at -10kPa. Marketable yield was not different among -50kPa, -100kPa, -30kPa and -20kPa and lowest at -10kPa. Sugar content of the flesh fruit at ripening stage was 15.1 $^。/Brix at -50kPa and 14.4 $^。/Brix at -10kPa Therefore, optimum irrigation point at ripening stage of fruit is -50kPa by 10mm dripping each time. time.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.288-292
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• 2008

This study was conducted to identify the effects of irrigation amount to produce high quality melon fruit in fertigation culture. Irrigation amount of during fruit harvesting period was doubled at the low irrigation point ($(-45{\sim}50\;kPa$) treatment as 115 mm as than that of the high irrigation point ($-20{\sim}25\;kPa$) treatment. The plant growth rates such as stem length, leaf weight and plant height were a little diminished at the low irrigation point ($-45{\sim}50\;kPa$) than those of the other treatments. Internode length was however not affected by irrigation amount. Fruit weight was lighter at the low irrigation point ($-45{\sim}50\;kPa$) than that of at the high irrigation point and fruit height was shorter, but fruit diameter was not affected by irrigation amount. Fruit soluble solid was $0.9^{\circ}Bx$ higher at the low irrigation point ($-45{\sim}50\;kPa$) than at the high irrigation point ($-20{\sim}25\;kPa$) and net index was higher. Total marketable yield was highest by 3,937 kg/10a at the high irrigation point ($-20{\sim}25\;kPa$), but the excellent marketable yield was highest by 2,531 kg/10a at the low irrigation point ($-45{\sim}50\;kPa$). Inorganic contents of the soil N, K, Ca and Mg were not affected by irrigation amount. It was therefore thought that optimum irrigation point to produce high quality melon fruit by fertigation culture was $-45{\sim}50\;kPa$ at ripening stage.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.236-242
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• 2012

This study was carried out to investigate the effect the water content in coir substrates as according to growth stage on the growth and yield of mini-paprika of three varieties 'E 499524' (red color), 'E 499526' (yellow colar) and 'E 499531' (orange colar) in summer hydroponics. Treatments of I, II and III were composed of 55-65-60, 50-60-55 and 45-55-50% in water contents of growth stages, respectively. Time domain reflectometry (TDR) sensors were used in a drip irrigation system. The early growth of mini-paprika was increased by high medium water content of treatment I in all of three varieties. Mean fruit weight was not affected by medium water content, but the fruit number per plant and yield were increased at high medium water content of treatment I. The Yield of treatment I was higher than that of treatment II and III in all of three varieties. The sugar content was increased by low medium water content of treatment in all of three varieties. The incidence of brown-stem fruit, blossom-end rot and sunburn was decreased with increasing water content of medium. Occurred in the low water content of medium. Mineral contents of fruits such as nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg) etc. were not affected in all of three varieties.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.258-262
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• 2011

This study was carried out to investigate the effect the water content in substrates as according to growth stage on the growth and yield of paprika in summer hydroponics. Treatments of I, II and III were composed of 55-65-60, 50-60-55 and 45-55-50 % in water contents of growth stages, respectively. Time domain reflectometry (TDR) sensors were used in a drip irrigation system. The early growth of paprika was increased by high medium water content of treatment I. Mean fruit weight was not affected by medium water content, but the fruit number per plant and yield were increased at high medium water content of treatment I. The yield of treatment I was higher than that of treatment II and III. The incidence of brown stem fruit, blossom end rot and sunburn was decreased with increasing water content of medium. Occurred in the low water content of medium. The nitrogen (N) was higher content in brown stem fruit than normal stem, but mineral contents such as potassium (K), calcium (Ca), magnesium (Mg) etc. were not affected.

• Journal of Bio-Environment Control
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• v.13 no.2
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• pp.102-106
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• 2004

Objective of this research was to investigate the effect of fertigation setting point such as -5, -10, -20, and -30 ㎪ on the growth and fruit quality of sweet pepper (Capsicum annuum L.) in greenhouse culture. The net $CO_2$ assimilation and transpiration rate were the lowest in the treatment of -30㎪. The pH and EC in soil solution were not severly affected by irrigation setting point and no statistical differences were observed among treatments of irrigation setting point tested. The N content of above ground plant tissue was the lowest in the treatment of -30 ㎪ and those of K, Ca, and Mg were the highest in the treatment of -10 ㎪. But that of P did not show statistical differences among treatments tested. As the fertigation setting point was getting low, the growth decreased at 60th day after planting, while there were no differences among treatments at 210th day after planting. The fruit quality except sugar contents did not show differences among treatments, but sugar contents was the highest in the treatment of -30 ㎪ with $8.0^{\circ}$Brix. Above results indicated that fertigation setting point should be in the range from -10 ㎪ to -20 ㎪ to ensure good crop growth and fruit quality in sweet pepper production.

• Research in Plant Disease
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• v.14 no.2
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• pp.85-89
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• 2008

Clubroot of Chinese cabbage, caused by Plasmodiophora brassicae, is one of the most serious plant diseases in the world. The objectives of this study were to investigate the effect of the irrigation times on the development of club root after planting and to evaluate the effect of clubroot disease on yield of chinese cabbage in pot and field. The clubroot disease gradually increased with increasing irrigation frequency after planting. The growth characters and yield of chinese cabbage by irrigation times varied according to soil moisture and clubroot disease severity. Based on marketable yield and control value, an ideal irrigation point was at the soil matric potential of 0.06 MPa. These results suggest that the suppression on clubroot disease development could be achieved by initially reduced irrigation times after planting. Future studies on irrigation times using fungicide treatment and resistant cultivar under natural field conditions are required to improve the control effect of clubroot.