• Korean Journal of Agricultural Science
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• v.24 no.1
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• pp.94-107
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• 1997

Producing organic farm products is one of the high-payoff farming practices considering the rapid increase of consumer's purchasing power. The purpose of this study is to identify the optimal organic farming system in relation to farm income. To cope with the above objectives, present farming conditions and profitability of 15 farmers producing organic products including rice and leaf vegetables as lettuse and cabbage were surveyed in Hongsung and Ahsan Gun, Chungnam Province. Based on the surveyed data, maximization of organic farm income were analyzed under the constrained conditions such as limited monthly labour inputs and competitive use of land by Linear Programming Model. The results of this study can be summarized as follows. 1. In the profitability analysis of 15 farmers producing organic products, rice farmers could earn their farm income more than that of conventional farmers by 50%. On the other hand, the controlled lettuce farmers could get more about 100% than that of it. But the controlled cabbage farm could get more about 40% of it. These organic farm products were saled at high prices comparing with the prices of conventional farm products by 170% ~ 230% even though the crop yields produced by organic materials had decreased. 2. According to the labor requirement of the organically produced crops, rice cultivation was needed more labour inputs than the conventional farming method by 130%. On the other hand lettuce and cabbage could saved labour requirement by 40% and 80% of those respectively. Especially for the rice cultivation concern, higher labor requirement was due to the activities as organic fertilization, soil preparation and pest and weed controll, etc. 3. With the surveyed data from farmers who produced farm commodities, L.P. analysis was implemented to find out the optimul farming system and the maximum income. According to the results of L.P. analysis, 58% of total farm income could get more than the conventional farming system In the case of rice cultivation, one ha of paddy was recommendable to save more labour inputs than the controlled leaf vegetables such as lettuse and cabbage. However, in the controlled leaf vegatables, only 73% of total upland equivalent to 0.3 ha should be cultivated under the condition of labor shortage as the restricted 4 workers. And increasing the size of hogs raising should be recommened to achieve self-sufficiency of organic fertilizer. As pointed out the possibility of organic farming, present farmers producing organic farm products could be able to maximize their income by expanding organic farm size with regard to all conditions of our organic industry. Of course, there are many difficulties in the course of developing organic agriculture. So Government should effort to support the development of our organic agriculture considering the various aspects of production, marketing, Quality certification of organic produces.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.399-401
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• 2015

This study investigated the plant growth promoting activity of geraniol on Chinese cabbage (Brasscia campestris ssp. Pekinensis Rupr.), Pak Choi (Brassica rapa L.), Crown daisy (Chrysanthemum coronarium L.), Iceberg lettuce (Lactuca sativa L.) and Leaf perilla (Perilla frutescens Britt.). Geraniol at 0.5 to $10mg\;L^{-1}$ promoted radical growth of Chinese cabbage Pak Choi, Crown daisy, Iceberg lettuce and leaf perilla by >30%. In the pot experiments, geraniol treatment at $20mg\;L^{-1}$ by drenching increased up to 190% of the aerial part growth promotion. By comparison, foliar application showed 124% promoting activity only at $100mg\;L^{-1}$.

• The Korean Journal of Pesticide Science
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• v.10 no.3
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• pp.183-188
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• 2006

A nation-wide monitoring survey was performed to look into pesticide use pattern and amount on farmers' field after the national registration of pesticides from 2003 to 2004. Tow hundred ninety two leading farmers involved in the survey were chosen from main cultivating regions of targeted crops in consideration with area. Most farmers involved in the survey follow the safe use guideline of pesticides, while their information to select and making-decision for purchasing pesticides were done according to the recommendation of mainly pesticide market dealers or agricultural cooperative dealers. Used amount of pesticide per unit cropping area was surveyed as 5.51 on paddy, 3.91 on field cabbage, 2.93 on greenhouse cabbage, 0.76 on lettuce, 0.55 on spinach, 1.34 on perilla leaf, 4.89 on leek and 0.42 kg $ha^{-1}$ on young radish. As compound with those surveyed from 1999 to 2000, the pesticide amounts used for rice, lettuce and perilla leaf were reduced while that for cabbage was increased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.143-148
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• 1992

The antimutagenic effects of green-yellow vegetables toward aflatoxin B$_1$(AFB$_1$) and 4-nitroquinoline-1-ox-ide (4-NQO) using the Ames assay system with Salmonella typhimurium TA98 and TA100 were studied. Forty six to fifty percent of the methanol extracts of the vegetable samples inhibited the mutagenicity induced by AFB$_1$in TA98 and TA100. Perilla leaf, lettuce, broccoli, crown daisy, water dropwort, small water dropwort, red pepper, red pepper leaves, amaranth, spinach and radish root were significantly reduced the mutagenicity of AFB$_1$(p< 0.01). Whereas 25 out of 27 samples (93%) exhibited antimutagenicity toward a direct mutagen of 4-NQO (p< 0.01. 0.05). The samples which showed the strong antimutagenicity (>60%) were cabbage, kale, lettuce, broccoli, mustard leaf, green red pepper, green sweet pepper, spinach, amaranth, soybean sprout and immature pumpkin. The juices from the several samples also showed antimu-tagenic activity toward AFB$_1$. Cabbage, perilla leaf, small water dropwort and spinach reduced TAT100 revertants dose dependently in the range of 50-500$m\ell$/plate, however, cucumber and carrot showed little effect.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.351-359
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• 2010

To establish the optimum artificial light illumination method for baby leaf lettuce in closed plant factory system, the effects of red/blue light quality and short-term light quality conversion on growth and anthocyanin content were investigated. The growth of 'Hongha' lettuce was most favorable under red single wavelength LED light after 23 days of treatment, sequentially followed by the growth under red/blue mixed light, blue light, and fluorescent light. Total anthocyanin content in the mixed red/blue light (R57-B43) was 4.1-fold and 6.9-fold increased compared to the red LED and fluorescent light, respectively. With increasing the blue light ratio to 43%, the growth of lettuce was significantly decreased, while the relative chlorophyll content and Hunter's $a^*$ value was increased, indicating that the red/blue light ratio inversely affects on growth and anthocyanin pigment development. By changing light quality from red to red/blue mixed light source (R57-B43) for 9 days before harvest, the growth rate decreased compared to the continuous red light illumination, while the anthocyanin content dramatically increased compared to either red LED or fluorescent light. Whereas, when the light source was changed to red light, the growth rate was increased but anthocyanin content was reversely decreased. The result demonstrated that both growth and anthocyanin expression could be effectively regulated by shifting of light quality between red and red/blue mixed light source at a specific growth stage of lettuce in a plant factory.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.242-248
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• 1992

This study was carried out to investigate the effects of root-zone temperature in hydroponics on the plant growth and nutrient uptake of lettuce(Lactuca sativa L), tomato (Lycopersicon esculentum Mill), and cucumber (Cucumis sativus L). Respiration rate in roots increased with increase in root-zone temperature. At $10^{\circ}C$ of root-zone temperature, respiration rate in lettuce root was higher than those in tomato and cucumber. Increasing rate of root respiration in tomato with increase in root-zone temperature was greater than those in lettuce and cucumber. The lowest dry weight and leaf area of the crops studied were obtained at $10^{\circ}C$ of root-zone temperature, but they were not different between 20 and $30^{\circ}C$. Increase in root-zone temperature generally resulted in increase in T/R ratio and net assimilation rate. At the low root-zone temperature, root growth and leaf area of tomato and cucumber were severely affected. Relative growth rates of lettuce and cucumber were also greatly reduced by the low root-zone temperature. Contents of N, P, K, Ca, and Mg in the crops increased as root-zone temperature increased from 10 to $20^{\circ}C$, whereas only Ca content in tomato and cucumber increased with increase in root-zone temperature to $30^{\circ}C$. Remarkably low contents of P and Mg in the crops were found at the low root-zone temperature. Inhibition of plant growth and nutrient uptake due to low root-zone temperature was much greater in cucumber than in lettuce and tomato.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.305-311
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• 2012

To investigate the influence electrical conductivity (EC) of nutrient solution and light intensity on growth of red leafy lettuce, fresh and dry weights, number of leave, chlorophyll concentration and production efficiency were evaluated through nutrient film technique system. The levels of EC were 0.5, 1.0, 1.5, 2.0, 3.0, and $6.0dS{\cdot}m^{-1}$, and those of light intensity were 120, 150, and $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Under photoperiod of 16 h/day, the temperature was maintained in the range of $20{\sim}25^{\circ}C$. Planting density was $10{\times}10cm$ (100 plants/$m^2$). When red leafy lettuce were grown in the EC range of $0.5{\sim}1.5dS{\cdot}m^{-1}$, the fresh and dry weights decreased as the EC levels and light intensity were lowered, however, Hunter's a value showed no significant differences among the treatments of EC and light intensity levels (Ex. 1). The fresh and dry weights and production efficiency ($g{\cdot}FW/kw$) were the highest in the treatment of $3.0dS{\cdot}m^{-1}$ and $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ when crops were grown under the EC range of EC $1.5{\sim}6.0dS{\cdot}m^{-1}$ (Ex. 2). But the fresh and dry weights, number of leaves, and production efficiency of $2.0dS{\cdot}m^{-1}$ were the highest when the light intensity was $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ (Ex. 3). The SPAD value increased gradually as EC levels were elevated. From the above results, we concluded that optimum levels of EC and light intensity were $2.0dS{\cdot}m^{-1}$ and $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively, for production as well as production efficiency of red leaf lettuce in plant factory.

• Journal of Biosystems Engineering
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• v.42 no.2
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• pp.104-111
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• 2017

Purpose: We have studied the necessary qualities of seedlings of some leafy vegetables for a riding-type two-row automatic transplanter. When seedlings are planted using a transplanter, long roots may be rounded in the bottom of the tray, and this can interfere with the separation of the seedlings. Uprightness related to leaf spread angle is an important quality for seedlings in mechanical planting. Methods: To select cultivars suitable for the transplanter, we compared varieties of Kimchi cabbage (Chukwang, Daetong, Whipalam and Namdo), head lettuce (Abi and Sensation), cabbage (YR Onnuri, YR Hogel, Harutama, and Ogane), and broccoli (Nicegreen and Earlyyou). To compare the effect of bed soil on root formation and growth, we used five types of soil: Chologi, Burger, Wonjomix, Bio, and Baroker with 2.6-3 L per tray. Growth increment and the degree of root formation were measured according to the RDA guidelines 25 days after sowing for Kimchi cabbage and head lettuce and 44 days after sowing for cabbage and broccoli. Conclusions: According to the plug tray, the optimum seedling age in both 128- and 200-hole trays was 28 days for Kimchi cabbage and 44 days for cabbage and broccoli. Head lettuce took 35 days in 128-hole trays and 31 days in 200-hole trays. Burger soil was most effective for root formation and growth of the four kinds of leafy vegetables; it appeared that smaller soil volume led to faster root formation.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.105-109
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• 2020

This study was conducted to the improvement of solar light-based artificial light supply system and effect of lettuce cultivation. The artificial light supply system was consisted of units such as light source, power, system measurement and controller. The light source supply was composed of a solar transmitter and an LED lamp. The power supply consisted of an leakage breaker, SMPS, LED controller and relay. The solar transmitter was made of a quartz optical fiber with optimal light transmission. Artificial light used white lamp among LEDs. System measurement and control consisted of touch screen, Zigbee communication module and light quantity sensor. The results of test confirmed that the LED light is automatically activated when the intensity measured by the light intensity sensor is 200 μmolm^-2s^-1 or less. Moreover, the leaf length, root length, chlorophyll content and root fresh weight of optical fiber treatment was hight than LED lamp treatment. Therefore, it can be inferred that the energy-saving solar light collector device can be effective in the indoor lettuce production. However, the use of LED lamp is also recommended to assure the availability of sufficient sunlight in cloudy and rainy days.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.1
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• pp.47-57
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• 2021

This study was conducted to evaluate the properties of mixtures of mixed organic fertilizer (MOF) and various organic sources such as livestock manure compost (LMC), dried compost of poultry manure (CPM), dried food waste powder (FWP) and amino acid by-product fertilizer (ABF) and their influences on growth of lettuce and Chinese cabbage. The content of N, P2O5 and K2O of mixture of MOF, LMC and FWP (MLF) was 3.6~3.9%, 2.1~2.2% and 1.3~1.4%, respectively. Lettuce dry weight of MLF3 treatment blending with MOF (60%), LMC (10%) and FWP (30%) was increased by about 29% than that of MOF. The content of N, P2O5 and K2O of mixture of MOF, CPM, FWP and ABF (MCFA) was 4.5~4.7%, 1.7~1.9% and 1.3~1.4%, respectively. Compared to MOF, growth factors of lettuce and Chinese cabbage in the MCFA treatments were not significantly deferent. These results indicated that MLFs and MCFAs, the mixtures of respectively organic sources and MOF, could be applied as orgnic fertilizer in the cultivation of lettuce and Chinese cabbage, and were expected that LMC and ABF might be used as another sources of organic fertilizer.