• Horticultural Science & Technology
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• v.35 no.4
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• pp.456-464
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• 2017

We examined the effect of nutrient solution concentration in the second half of growing period on the pre- and postharvest characteristics of two leaf lettuce cultivars, 'Geokchima' and 'Cheongchima'. Plants were grown hydroponically in a deep flow technique (DFT) system at different concentrations of National Horticulture Research Institute hydroponic nutrient solution: 1/2 strength (S), 1S, 2S, and 4S. Lettuce leaf growth, number of leaves, and shoot fresh weight of both cultivars were greatest in plants grown in the 1S treatment. Compared to other treatments, pigment and nutrient ion contents were greater in the 4S treatment. Growth of lettuce was greatest in the 1S treatment, and decreased at higher or lower concentrations of nutrient solution. However, postharvest characteristics such as fresh weight loss, leaf chlorophyll level, and external appearance were better in both cultivars when grown in 2S solution. Variations in weight loss and SPAD values were smallest in the 2S treatment. These results show that the optimal nutrient concentration for growth does not necessarily provide the optimal postharvest storability.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.358-365
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• 2019

An agrivoltaic systems (AVS) is mixed systems associating photovoltaic panels (PVPs) and crop cultivation at the same time on the given land area. It is receiving attention to improve rural economy. However, it is likely that, the crop yield should be decreased due to the reduced absorption of solar radiation by leaves. Thus, before popularizing the AVS, it is necessary to comprehend the degree of shading by PVPs in AVS. In this study, the change of radiation condition under AVS mimic shading net was investigated. The minimum and maximum of difference of photosynthetically active radiation (PAR) between under and outside shading net were 3.03 mol/㎡/day on a cloudy day and 17.08 mol/㎡/day on a sunny day. This difference decreased when the ratio of diffuse irradiance to global irradiance increased. Such a shading effect resulted in the increase of rice height and decrease of rice tillering.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.542-549
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• 2015

This work was carried out to evaluate the effects of preharvest 1-methylcyclopropene (1-MCP, $Harvista^{TM}$) and postharvest 1-MCP ($SmartFresh^{TM}$) treatments on the fruit quality attributes of cold-stored 'Fuji' ( Malus domestica Borkh.) apples. Fruits were exposed to 0, 95, 125, or $250 mg{\cdot}L^{-1}$ $Harvista^{TM}$ at 3, 2, 1 weeks before harvest (WBH), and treated with 0 or $1{\mu}{\cdot}L^{-1}$ $SmartFresh^{TM}$ at harvest. Fruit was then stored for up to 180 days at $0{\pm}1^{\circ}C$. Fruit fresh weight, Hunter's value a, internal ethylene concentration (IEC), flesh firmness, titratable acidity (TA), and soluble solids content (SSC) in fruit treated with $Harvista^{TM}$ were not different from those of control fruit at harvest. During cold storage, flesh firmness and TA were higher in fruit treated with $250mg{\cdot}L^{-1}$ $Harvista^{TM}$ at 2 and 3 WBH than in control fruit. IEC was 5.5-10.0% lower in fruit treated with $250mg{\cdot}L^{-1}$ $Harvista^{TM}$ at 2 and 3 WBH compared with control fruit as storage duration progressed, while SSC was not affected. Furthermore, flesh firmness, TA, and IEC were affected neither by $Harvista^{TM}$ nor $Harvista^{TM}+SmartFresh^{TM}$ treatments, compared with those fruit quality attributes at harvest. The correlation maps indicated that IEC was negatively correlated with firmness and TA, regardless of $Harvista^{TM}$ application levels. In addition, positive correlations between fruit quality attributes were detected in treatments with $250mg{\cdot}L^{-1}$ $Harvista^{TM}+SmartFresh^{TM}$. Therefore, the results suggest that with a single application of $SmartFresh^{TM}$, a higher level of $Harvista^{TM}$ application would help in retention of fruit quality attributes during cold storage.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.783-789
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• 2010

The effective method for heating root-zone during winter season was studied in the aspects of growth, yield and economics for tomato ($Solanum$ $lycopersicum$) in perlite bag culture. There were four root-zone heating treatments: two hours heating from one hour before to one hour after sunrise, four hours from two hours before to two hours after sunrise, 15 hours after sunset, and no heating. The growth characteristics of the upper parts of plants were not significantly different among the treatments, but root volume increased with longer heating of the root zone. The Plant Development Index, using stem diameter and the length between growing tip and the upper flowering truss, showed relation between yield per cluster and growth pattern. The treatment heating for four hours was the most economic in terms of growth and yield of tomato.

• Korean Journal of Remote Sensing
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• v.33 no.5_2
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• pp.721-732
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• 2017

With the increasing socio-economic importance of rice as a global staple food, several models have been developed for rice yield estimation by combining remote sensing data with carbon cycle modelling. In this study, we aimed to estimate rice yield in Korea using such an integrative model using satellite remote sensing data in combination with a biophysical crop growth model. Specifically, daily meteorological inputs derived from MODIS (Moderate Resolution imaging Spectroradiometer) and radar satellite products were used to run a light use efficiency based crop growth model, which is based on the MODIS gross primary production (GPP) algorithm. The modelled biomass was converted to rice yield using a harvest index model. We estimated rice yield from 2003 to 2014 at the county level and evaluated the modelled yield using the official rice yield and rice straw biomass statistics of Statistics Korea (KOSTAT). The estimated rice biomass, yield, and harvest index and their spatial distributions were investigated. Annual mean rice yield at the national level showed a good agreement with the yield statistics with the yield statistics, a mean error (ME) of +0.56% and a mean absolute error (MAE) of 5.73%. The estimated county level yield resulted in small ME (+0.10~+2.00%) and MAE (2.10~11.62%),respectively. Compared to the county-level yield statistics, the rice yield was over estimated in the counties in Gangwon province and under estimated in the urban and coastal counties in the south of Chungcheong province. Compared to the rice straw statistics, the estimated rice biomass showed similar error patterns with the yield estimates. The subpixel heterogeneity of the 1 km MODIS FPAR(Fraction of absorbed Photosynthetically Active Radiation) may have attributed to these errors. In addition, the growth and harvest index models can be further developed to take account of annually varying growth conditions and growth timings.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.2
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• pp.58-65
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• 2001

To produce the substitute for farmland were mixed concrete waste and organic wastes. To estirnate the application of the mixture for farmland components in the solid and the leachate from the mixture were analyzed according to the ordinance of the Waste Society in Germany. Plants were cultivated in the mixture and its harvests were measured. The results showed that the mixture from waste may be used for the reclamation of landfill and landscaping according to circumstances, and the best mixture was from 85% of concrete waste, 10% of sewage sludge and 5% of paper mill sludge.

• Horticultural Science & Technology
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• v.17 no.2
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• pp.115-117
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• 1999

Tomato (Lycopersicon esculentum) fruits were grown by the hydroponic cultivation system using perlite and soil cultivation system. The growth, yield, and fruit quality were compared between two growing seasons of spring and summer and two cultivation systems, respectively. In tomato, little difference was observed in growth and yield between two cultivation systems, but plant growth and total yield of fruits were much more in summer than in spring. The contents of glucose and fructose were more in spring-grown fruit than in summer-grown one, and in hydroponically cultivated fruit than in soilcultivated, respectively. The weight loss during room temperature storage was lower in hydroponically cultivated fruit than in soil-cultivated one, and in summer-grown fruit than in spring-grown one, respectively. In terms of color change, the shelf-life of tomato fruit was shorter by one day in summer-grown one fruit than in spring-grown one, and in hydroponcically cultivated one fruit than in soil-cultivated, respectively.

• Horticultural Science & Technology
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• v.18 no.3
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• pp.395-398
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• 2000

This study was conducted to evaluate the effect of harvest time, temperature and ethephon on the softening of astringent persimmon 'Cheongdobansi'. The persimmon was harvested on Sep. 21 (early season harvesting) and Oct. 11 (optimum season harvesting). Quality changes were evaluated at 10, 15 and $20^{\circ}C$ after ethephon treatment. Seventy percent of hardness decrease occurred during the first 2 days of treatment at 15 and $20^{\circ}C$, and hardness was slowly decreased after 6 days. The treatment of $10^{\circ}C$ was not effective on inducing fruit softening. Soluble tannin content was sharply decreased 6 days after ethephon treatment at 15 and $20^{\circ}C$ regardless the harvest time, whereas this was much slower in control. Hunter 'L' and 'b' values were increased until 2 days, and then decreased with the early harvested persimmon. The Hunter values were decreased until the 8th day of storage in fruit harvested at optimum season.

• Korean journal of applied entomology
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• v.43 no.1
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• pp.27-34
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• 2004

This study was conducted to develop optimal control tactics of the northern root-knot nematode, Meloidogyne hapla, using cultural method and biological agents ｛Bacillus thuringiensis (Bt), Paecilomyces lilacinus and plant extract (Huhjunl)｝ in the fields of Codonopsis lanceolata. Germination of C. lanceolata was susceptible to fosthiazate, but not to Bt or a plant extract. In pot assay, the inhibitory effect of two microbial agents, Bt and Paecilomyces lilacinus, on M. hapla were significant, but less than that of fosthiazate. The plant extract also had significantly inhibitory effect on M. hapla. In field assay, treatments of P lilacinus and fosthiazate resulted in maximal yields and qualities of C. lanceolata. The effect of the plant extract on the yields of C. lanceolata was also better than no treatment. The nematode-occurring condition of the fields before transplanting had significant effect on development of C. lanceolata; nematode-occurring field type gave less yields than nematode-free field type. These results suggest that a cultural control technique using paddy field, microbial pesticides using Bt or P lilacinus, and the plant extract are the promising control tactics against M. hapla in C. lanceolata fields. As a field manual to decrease economical damage of C. lanceolata due to M. hapla, this study suggests that C. lanceolata can be cultured directly in paddy field or in upland field after nematode control using microbial agents or the plant extract.

• Korean Journal of Organic Agriculture
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• v.21 no.2
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• pp.283-294
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• 2013

Root-rot disease is a serious problem in ginger cultivation fields and it reduces the quality and productivity of ginger. This study was conducted to investigate the effects of different soil physical and chemical properties on the changes of ginger growth. As comparing the selected soil chemical properties after harvesting the ginger plants with those before planting them, the contents of total nitrogen and exchangeable $Mg^{2+}$ increased, whereas electrical conductivity (EC) and exchangeable $K^+$ content decreased. Potassium (K) concentrations in ginger plant were markedly higher in both its shoot and root parts ranging from 63.9 to $72.3g\;kg^{-1}$ and from 27.6 to $37.3g\;kg^{-1}$, respectively, which might be related to the decrease of exchangeable $K^+$ content in soils. Incidence rate of ginger root-rot disease in the plots ranges between 26.7% and 88.1%. It was higher in low elevation plots with clay loam soils than in high elevation plots. In addition, the incidence of the disease increased as affected by high temperature and humid condition during the growth and maturity stages of ginger. Therefore, soil texture, field slop, and drainage system as well as chemical properties should be considered to cultivate ginger plant.