• Horticultural Science & Technology
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• v.34 no.1
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• pp.77-83
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• 2016

The measurement of total fresh weight of plants provides an essential indicator of crop growth for monitoring production. To measure fresh weight without damaging the vegetation, image-based methods have been developed, but they have limitations. In addition, the total plant fresh weight is difficult to measure directly in hydroponic cultivation systems because of the amount of nutrient solution. This study aimed to develop a real-time, precise method to measure the total fresh weight of Romaine lettuce (Lactuca sativa L. cv. Asia Heuk Romaine) with growth stage in a plant factory using a nutrient film technique. The total weight of the channel, amount of residual nutrient solution in the channel, and fresh shoot and root weights of the plants were measured every 7 days after transplanting. The initial weight of the channel during nutrient solution supply (Wi) and its weight change per second just after the nutrient solution supply stopped were also measured. When no more draining occurred, the final weight of the channel (Ws) and the amount of residual nutrient solution in the channel were measured. The time constant (${\tau}$) was calculated by considering the transient values of Wi and Ws. The relationship of Wi, Ws, ${\tau}$, and fresh weight was quantitatively analyzed. After the nutrient solution supply stopped, the change in the channel weight exponentially decreased. The nutrient solution in the channel slowly drained as the root weight in the channel increased. Large differences were observed between the actual fresh weight of the plant and the predicted value because the channel included residual nutrient solution. These differences were difficult to predict with growth stage but a model with the time constant showed the highest accuracy. The real-time fresh weight could be calculated from Wi, Ws, and ${\tau}$ with growth stage.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.73-80
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• 2011

To investigate the characteristics of plant growth and flower quality of gerbera 'Sunny Lemon' by amount of nutrient solution, young seedling plants, 'Sunny Lemon' were transplanted to rock-wool and medium of peat moss and perlite mixed with 1 to 2 and they were acclimatized in greenhouse during about 1 month. Nutrient solution supplied to the plants is sonneveld solution of 1/2 concentration and treatments launched June 24, 2010 when average plant height was $20{\pm}1cm$. Nutrient contents as a standard for starting point of irrigation by time domain reflectometry (TDR) were determined with 60-65%, 70-75%, and 80-85%. Results of growth during vegetative growth, plant height, leaf width and leaf number increased by 10% in rockwool, but they were not significantly different. As for plant growth depending on nutrient content, 80-85% treatment showed the highest values. Leaf number increased by 60%, and leaf width and plant height had a about 40% increase than initial growth. Effectiveness for flower quality, yield and days to flowering were superior when nutrient content of media was higher than in the others. Especially, average days to flowering in 80-85% content was advanced by 7-10 days compared to the day in 60-65% treatment. The total amount of nutrient supply per plant was higher in mixed medium than in rockwool, but change patterns of EC and pH were enhanced in rockwool. Based on our results, we recommended that growth, cut flower, and yield of gerbera 'Sunny Lemon' were more effective when nutrient content of mixed medium was maintained at 80-85%.

• Horticultural Science & Technology
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• v.31 no.2
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• pp.179-185
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• 2013

This study was carried out to find a reasonable irrigation method of a nutrient solution for the phenolic foam slab (foam LC) used in a trial experiment to substitute the rockwool slab in the production of paprika (Capsicum annuum 'Veyron'). 100, 90, and 80 mL of a nutrient solution was supplied per plant each time when the accumulated radiation reached to 100, $90J{\cdot}cm^{-2}$, and they were named as the 100-100, 90-90, and 90-80 treatment, respectively. The drain percentage per plant of the 100-100 treatment was high by 33.8% in rockwool and 36.7% in foam LC (Lettuce Cube) and that of 90-80 treatment was low by 30.4% and 33.7%. The water content and EC of the rockwool slab were maintained in the range of 63.6-68.9% and $4.4-5.1mS{\cdot}cm^{-1}$, while those of the foam LC slab were in the range of 52.9-58.8% and $5.5-6.5mS{\cdot}cm^{-1}$. The plant height and leaf size of the 100-100 and 90-90 treatments increased in a similar manner, while those of the 90-80 treatment decreased and those of the rockwool were greater than those of the foam LC. The fruit size and weight of the 100-100 and 90-90 treatments were similarly bigger and heavier than those of the 90-80 treatment. The number of fruits harvested per plant was the greatest in the 90-80 treatment with 8 and 8.3 fruits in the rockwool and foam LC. The number of marketable fruits in the rockwool and foam LC was the greatest with 18.1 and 18.2, respectively, in the 90-90 treatment, while that in the 90-80 treatment was 17.2 and 16.8, respectively. The number of unmarketable fruits of the 90-80 treatment was the greatest (1.7-1.8 fruits per plant) in both the rockwool and foam LC, and most of them were small sized or blossom end rot fruits. The yield of the 90-90 treatment was the greatest among the irrigation.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.421-427
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• 2020

In this study, we investigated the effect of nutrient supply periods on the fruit growth and quality of 'Duke' blueberry. The nutrient solution was contained with NO₃-N 4.6, NH₄-N 3.4, PO₄-P 3.3, K 3.0, Ca 4.6, and Mg 2.2 mmol·L^-1, and EC in the nutrient solution was 1.5 ds.m^-1. In 2017 and 2018, an individual blueberry bush was supplied with 8 L of the nutrient solution per week. In 2018, the drainage water quality of growing medium and fruit quality was investigated. The nutrient supply was started from April 01, and stopped at 15 days intervals as follows, 15 days before final harvest, at the final harvest date (June 30), 15 days after final harvest (DAFH), 30 DAFH, 45 DAFH, and 60 DAFH. The content of inorganic components in the growing medium was not significantly different by the stop time of nutrient supply, but the content of phosphorus (P₂O₅) tended to increase with the delay of stop time of nutrient supply. There were no significant differences in the fruit quality characteristics in terms of size, sugar content, and acidity among the different stop time of nutrient supply. The blueberry yield was tended to decrease with the delay of periods of nutrient supply, while the lowest yield of 1.8 kg was recorded when nutrient supply stopped at 45 and 60 DAFH.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.767-772
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• 2011

The purpose of this study was to find out required time for recovery of nutritional disorder by Fe-DTPA treatment in induced Fe-deficient tomato cultivars and to select stable Fe-chelate in high pH of nutrient solution. The pH levels of nutrient solution were amended with 6.0, 7.0, and 8.0. Then Fe-EDTA (Ethylenediaminetetraacetic acid, ferric-sodium salt), Fe-DTPA (Sodium ferric diethylenetriamine pentaacetate), and Fe-EDDHA (Ethylenediamine-N,N-bis (2-hydroxyphenylacetic acid) ferric-sodium salt)) were treated as Fe $2.0mg\;L^{-1}$ concentration. The Fe-DTPA and Fe-EDDHA were stable in the nutrient solution of pH 6.0~8.0 but Fe-EDTA in nutrient solution of pH 8.0 was to become insoluble by 25%. The Fe $2.0mg\;L^{-1}$ as Fe-DTPA was treated for recovery of Fe deficient tomato seedlings. In case of Redyoyo and Supersunroad cultivars, total chlorophyll and Fe contents of leaves were recovered as much as those of normal leaves in 5 days. The Rafito cultivar for complete recovery was taken 7 days. When Fe $2.0mg\;L^{-1}$ as Fe-DTPA was supplied to Fe-deficient tomato seedlings, in geotype, heme oxigenase recovered as much as normal leaves in 24 hours in the Rafito and Redyoyo. However, it was not remarkable difference by elapsed time in the Supersunroad.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.1
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• pp.19-27
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• 2021

Hydroponic farming is a method to grow a plant without soil. Plants can be grown on water or hydroponic growing media, and they are fed with mineral nutrient solutions, which are fertilizers dissolved into water. Hydroponic farming has the advantage of increasing plant productivity over conventional greenhouse farming. Previous studies of hydroponic nutrient wastewater from acyclic hydroponic farms pointed out that hydroponic nutrient wastewater contained residual nutrients, and they were drained to a nearby river bank which causes several environmental issues. Also, previous studies suggest that excessive use of the nutrient solution and disposal of used hydroponic growing media and crop wastes in hydroponic farms are major problems to hydroponic farming. This study was conducted to determine the impact of hydroponic nutrient wastewater, used hydroponic growing media, and crop wastes from acyclic hydroponic farms on the surrounding environment by analyzing water quality and soil analysis of the above three factors. Three soil cultivation farms and several hydroponic farms in the Gangwon C region were selected for this study. Samples of water and soils were collected from both inside and outside of each farm. Also, a sample of soil and leachate from crop waste piles stacked near the farm was collected for analysis. Hydroponic nutrient wastewater from acyclic hydroponic farm contained an average of 402 mg/L of total nitrogen (TN) concentration, and 77.4 mg/L of total phosphate (TP) concentration. The result of TP in hydroponic nutrient wastewater exceeds the living environmental standard of the river in enforcement decree of the framework act on environmental policy by 993.7 times. Also, it exceeds the standard of industrial wastewater discharge standards under the water environment conservation act by 6~19 times in TN, and 2~27 times in TP. Leachate from crop waste piles contained 11,828 times higher COD and 395~2662 times higher TP than the standard set by the living environmental standard of the river in enforcement decree of the framework act on environmental policy and exceeds 778 times higher TN and 5 times higher TP than the standard of industrial wastewater discharge standards under the water environment conservation act. For more precise studies of the impact of hydroponic nutrient wastewater, used hydroponic growing media, and crop wastes from acyclic hydroponic farms on the surrounding environment, additional information regarding a number of hydroponic farms, arable area(ha), hydroponic farming area, seasonal, weather, climate factor around the river, and the property of the area and farm is needed. Analysis of these factors and additional water and soil samples are needed for future studies.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.377-384
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• 2009

This study was conducted to examine the effects of electrical conductivity (EC) and rootstock on initial growth and physiological response of grafted pepper in protected cultivation. The pepper (Capcicum annuum L.) cultivars 'Nokgwang' was used as scions, and the cultivars used as rootstocks were Capcicum annuum L: 'Kataguruma', 'Conesian hot' and 'Tantan'. The scion cultivar left ungrafted was used as a control. Two experiments were to examine the effects of the EC levels of nutrient solution on the growth and physiological response of grafted pepper, respectively. Nutrient solution was supplied with three level (1.5, 3.0, 5.0dS/m). By the change of nutrient solution EC level, the plant growth of all seedlings decreased with the increase in EC level. grafted seedling was grafted onto rootstock cultivar 'kataguruma' showed higher growth than the other cultivar at the EC 5.0dS/m level. But this result was slightly different by cultivation time (spring and fall). The total N and P concentration were increased with the increase in EC level, but the Ca and Mg concentration were decreased. Photosynthetic rate of ungrafted seedlings decreased at the EC 5.0dS/m level. But there was no difference between EC 1.5 and 3.0dS/m level. Grafted seedlings showed lower photosynthetic rate at the EC 5.0dS/m level. The activity of SOD do not have a uniformly tendency by the EC level. With the EC 5.0dS/m level, the activity of APX attained higher level than the other EC level. Further study will be needed to examine additional cultivation experiment for more variable rootstock, and development of rootstock for salinity tolerance.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1300-1305
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• 2011

The study was conducted to investigate the characteristics of flower quality and yield of gerbera 'Sunny Lemon' by mutrient solution strength and media of nutrient solution. The plant growth of 'Sunny Lemon' showed the highest values in the media of rockwool and perlite 1: peatmoss 2. Especially the yield of cut flowers for a year was more than 60 flowers and the flower longevity was over 10 days irrespective of nutrient solution concentration in the two media. There were no significant differences of plant characteristics in the nutrient concentration of 1/2 and 1 times, and the mineral nutrient contents showed similar values. Therefore, we recommended the media of perlite1: peatmoss2 with the concentration of 1/2 times for economical use. The rockwool media was not appropriate because of the weak buffer capacity like EC and pH.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.226-226
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• 2018

고품질 농산물의 수요가 증가함에 농업인의 물관리에 대한 관심 또한 높아져 밭 관개용수에 대한 요구가 늘어나고 있는 실정이다. 밭관개용수 확보는 경제적인 작물로 작목 변환이 가능하고 1모작에서 3모작까지 가능하여 높은 생산성을 확보할 수 있다. 따라서 안정적인 용수 공급을 위해 밭 관개시설의 용수공급을 위한 적정용수 확보 방안 연구가 필요하다. 밭농업의 경우는 과거부터 대부분 지하수를 이용하는 구조로 지금까지 이어져 오고 있다. 밭관개용수 확보 방안을 제시하기 위해 지하수와 지표수의 현황 조사 결과 최근 지하수는 전국적으로 수위가 낮아지고 있으며, 특히 가뭄시 지하수위 저하에 따른 용수공급이 어려울 것으로 예상된다. 지표수는 저수지나 하천에서 취수하여 콘크리트 또는 토공수로를 통해 공급되는 특성상 부유물 유입이 많고 오염원에 쉽게 노출되어 있다. 따라서 양액관개, 점적관개 등 시설농업에 많이 사용되는 첨단농업기술을 접목한 용수장치에 적용하기에는 부적합하므로 이에 따른 대처가 필요하다. 수질오염이 심각한 지역은 간이 정수장 설치?운영을 필요하며 기존의 정수처리방법은 비용이 상당히 많이 소요되기 때문에 경쟁력이 떨어지므로 저비용의 시설용수공급시스템 개발이 요구된다. 본 연구에서는 밭지대 용수확보를 위한 방안으로 지표수를 이용한 저류조 공급을 제안하고 아울러 수질문제를 해결하기 위한 저류조에 여과장치를 통한 수질 개선 및 수온 유지를 통한 열선처리를 적용한 다기능 저류조를 개발을 연구하고자 한다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.200-204
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• 2003

This study was conducted to develop a technology for raising seedlings hydroponically using the bed in which the seedlings grew in nutrient solution without soil. In order to establish the optimum EC value of nutrient solution, six initial EC values (1, 2, 3, 4, 5 dS/m and control) of Yoshida's hydroponic solution were examined. Seedling height and dry weight increased with increasing below EC up to 3.0 dS/m, but showed no significant increase at higher than EC 3.0 dS/m. Nutrient solution with initial EC of 3.0 dS/m was good to be dropped down nearly to 1 dS/m after 15-day seedling culture. But those with initial EC of 4.0 and 5.0 dS/m were judged not appropriate because of high EC value in waste nutrient solution. Utilization efficiency of minerals of nutrient solution and rice endosperm was higher on the whole at initial EC of 2.0-3.0 dS/m. Considering seedling growth and utilization efficiency of supplied nutrient solution, initial EC is judged to be suitable at 3.0 dS/m.