• Journal of Bio-Environment Control
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• v.7 no.3
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• pp.253-258
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• 1998

Lettuce plants(Lactuca sativa var. capitata L.) were subjected to nitrogen starvation for 18, 14, 11, 7, and 0 days before harvest. The nitrate content of lettuce was decreased greatly by nitrogen starvation and also its fresh weight. The nitrate content of the middle part of leaves was lowest at the treatment of 18 days before harvest. In the inner part it was lowest at the treatment of 11 and 14 days before harvest. The longer the period of nitrogen starvation was, the more were decreased the absorption rates of cations at harvest. During the experiment, the pH was decreased except the treatment of 7 days before harvest. The EC was continuously increased regardless of treatments.

• 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 PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.3
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• pp.231-236
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• 2022

The research was aimed to improve pre-harvest methods to maintain marketability in postharvest leaf lettuce. In this study, the effect of hydroponics on the growth and post-harvest storage characteristics of 'Chongchima' lettuce grown in peat mass medium hydroponic system using a non-powered culture device or deep water culture (DWC) was evaluated. There was no difference in fresh weight, leaf number, SPAD, moisture content, and C/N ratio between peat moss growing medium hydroponic and DWC methods except plant height. It was found that lettuce cultivation by a nonpowered hydroponics method is easier than the existing DWC. The quality parameters, such as fresh weight loss, SPAD value, and general appearance of lettuce were investigated after harvest. There was no significant difference in fresh weight loss and general appearance during storage of lettuce by the hydroponics methods. However, with the increased storage time of SPAD, which is related to chlorophyll content, was slightly higher in peat moss medium hydroponic was than DWC. When crops such as lettuce are grown under favorable conditions without any agronomic abnormalities, it is suggested that post-harvest storage is not significantly affected by peat moss growing medium hydroponic and DWC.

• Korean Journal of Plant Resources
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• v.36 no.5
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• pp.517-526
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• 2023

The harvest time of the late-ripening 'Fuji' apple (Malus × domestica) is variable, depending on the coloration of the fruit skin. Ethephon, a plant growth regulator, promotes the ethylene production and induces physiological responses associated with fruit maturation in climacteric fruit crops, such as apples. This study aimed to investigate the effect of ethephon treatment on fruit characteristics after fruit enlargement, with the objective of proposing an economical and stable harvest control method for 'Fuji'/M.26 apples. Fruit characteristics were assessed at 10-days intervals following the application of 100 mg/L ethephon and mixture of 100 mg/L ethephon and 0.5% CaCl₂ at 145 days after full bloom (DAFB). Starch contents of ethephon-treated (ET) and ethephon with CaCl₂-treated (EC) apples began to decrease from 155 DAFB, and the starch contents of ET and EC at 10 days before harvest were similar to those of control at harvest time. Red coloration of fruit skin in EC was lower compared to ET but higher than control. The average fruit firmness was low in ET, while the control and EC exhibited similar levels of firmness. Fruit sugar acid ratios did not show significant differences between treatments. However, the titratable acidity of EC was significantly lower than that of the control at 10 days before harvest. Moreover, fruit sugar acid ratio of ET and EC at 10 days before harvest in 2021 was similar to their sugar acid ratio at harvest time. Therefore, it was thought that fruit maturation and skin coloration could be accelerated by 10 days from the harvest time through the combined treatment of 100 mg/L ethephon and 0.5% CaCl₂ at the end of fruit enlargement in 'Fuji'/M.26.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.307-314
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• 2006

Elevation differences within a paddy field relate strongly to plant health, crop homogeneity, and pest control. For precision agriculture (PA), the elevation within a field should be precisely controlled. We analyzed variation in elevation within two rice paddies over one crop cycle. The study took place in two rectangular plots (Field A and Field B, each $50m{\times}30m$). Elevations within the two plots were measured by a laser-equipped surveying instrument, that could determine elevations to precisions of 1 mm. The test fields were divided into grids with 30 squares; elevation was measured at the center of each $5{\times}10-m$ grid square. This study measured elevation during nine observation periods from pre-plowing to post-harvest. Descriptive statistics showed the highest elevations after plowing due to soil disturbance. One-way analysis of variance (ANOVA) revealed significant elevation differences before and after plowing and transplanting, although elevations were similar over the period of crop growth. Comparison of pre-plowing and post-harvest data showed differences in elevations, indicating that elevation changes occurred during plowing, rice transplanting, plant growth, and harvesting. In summary, the above statistical analyses indicated that elevation changes occurred due to plowing but not during the plant growth season or due to harvesting.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.95-101
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• 2012

This study was conducted to investigate the effect of climate conditions during cultivation and harvesting on the quality and storability of fresh bulb cabbage (Brassica oleracea L. var. capitata). Plug seedlings of six cabbage cultivars were transplanted to Gangneung-Wonju University high elevation research station in Gangwon province (780 m above sea level, lat. $37.5^{\circ}N$.) and harvested with four different harvest times like August 3 ($1^{st}$), August 13 ($2^{nd}$), August 23 ($3^{rd}$), and September 10 ($4^{th}$), respectively from 50 days after transplanting. Weight loss, Hunter color factors, firmness, and soluble solids content (SSC) of the cabbage bulbs were investigated during storage at $3^{\circ}C$ (85% RH) and $25^{\circ}C$ (60% RH). Decreased bulb weight and poor quality cabbages were apparent at the late transplanting (July 14) and harvest (September 10) respectively. Quality index such as firmness and SSC at August 23 ($3^{rd}$) harvested cabbage was better than August 3 ($1^{st}$) and August 13 ($2^{nd}$) cabbages due to the good weather condition just before harvesting. The cv. 'Speed king' and 'Minix 40' showed good qualities among the cultivars, especially when the bulbs were harvested during sunny day conditions from one week before harvesting. Also SSC was influenced by weather condition before harvesting rather than transplanting date, while firmness was influenced by transplanting and harvest date. However, the differences among the cultivars were not significant. The potential of storage as maintaining the quality was different, depending on weather conditions at harvest time. Generally the storage periods of six cultivars were around 3~5 days and 9~10 days at room and low temperature, respectively. However, the August 3 ($1^{st}$) harvested cabbage lost their marketable quality very fast because of rainy and cloudy weather condition before harvesting and also storability of bulbs was 2 days and 4 days at room temperature and $3^{\circ}C$, respectively. Quality index was also not significant difference among cultivars.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.437-446
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• 2013

This study was conducted for three years (2007, 2009, and 2010) to investigate the changes in fruit quality during maturation, and the quality and storage ability of fruits harvested at different times of 'Fuji' apple in Daegu region with a high air temperature during the fall season. Changes in apple fruit quality during the maturation period were investigated from 120-135 days to 183-198 days after full bloom. In comparing quality and storage ability of fruits harvested at different times, fruits harvested more than 180 days after full bloom were used. During the maturation period, poor coloring was the problem for 'Fuji' apple in Daegu region by the high air temperature about $20^{\circ}C$. In comparing quality of fruits harvested at different times, the soluble solid contents and hunter a value were increased by the extended harvest time. Fruit weight during harvest was not affected by different harvest time, while the fruit firmness and titratable acidity during harvest were decreased critically when the freezing damage happened. Ethylene production, fruit firmness, and titratable acidity during cold storage for twenty weeks did not differ according to the different harvest time. Soluble solid contents of fruits harvested at 216 days after full bloom in 2009 were similar at the time of harvest and cold storage. For fruits harvested at 201 days after full bloom, soluble solid content during cold storage was higher than during harvest time. However fruit firmness, soluble solid content, and titratable acidity after cold storage of fruit harvested after freezing damage was lower than those of the fruit harvested before freezing damage. The results show that the extended harvest time of 'Fuji' apples about 2-4 weeks from 180-200 days after full bloom in area with above-air temperature during fall season was seemed to be beneficial to enhancing soluble solid contents and fruit red color, but harvesting after the middle of November was dangerous because minimum air temperature began to fall under $-3.0^{\circ}C$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.2
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• pp.125-130
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• 2008

This study analyzed the growth, seed quality, and yield of major early-maturing soybean cultivars by comparing them in order to utilize the research results in the selection of early-maturing soybean cultivars in multi-cropping farms in the Southern area. This field trial was conducted at Naju region (latitude $35^{\circ}04'N$, longitude $126^{\circ}54'E$), Jeonnam, with planting on June 15. The maturing date for Keunol-kong and Hwaseong-put-kong was found to be around September 12, which was earlier than other cultivars. Thus, there were advantages to introducing a cropping system as well as having good seed quality and high yield. On the other hand, the maturing date for Saeol-kong and Sinrok-kong was found to be around September 20, which was a little bit late; however, the seed quality of the cultivars was good and they had a high yield. Therefore, if we want to sow the following crops of soybeans around mid-September, Keunol-kong and Hwaseong-put-kong are advantageous, while for the seeding around late September, Saeol-kong and Sinrok-kong would be good. This study was also performed to identify the limitation time for early harvesting by reviewing seed quality and yield of major early-maturing soybean cultivars according to early harvesting. When harvesting Keunol-kong on September 6, which was six days earlier than the optimal harvesting time (September 12), there was no difference in seed weight, yield, or seed quality than those of the harvested at the optimum maturing time. As for Saeol-kong, when harvesting on September 18, which was six days earlier than the optimal harvesting time (September 24), there was no difference in seed weight, yield, or seed quality than those of the harvested at the optimum maturing time. Therefore, the stable limitation time for early harvesting of Keunol-kong and Saeol-kong was concluded to be six days earlier than the optimal harvesting time.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.4
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• pp.287-292
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• 2016

The objective of this study was to determine the effect of harvesting time of rice on growth characteristics and dry matter yields of Italian ryegrass (Lolium multiflorum Lam., IRG) 'Kowinearly' after seeding them in paddy field. Experiments were performed in National Institute of Animal Science, RDA (Cheonan, Choongcheongnam-do province of Korea) for four years (2011~2014). Italian ryegrass variety 'Kowinearly' was seeded at experimental paddy fields before rice harvest in late September. Rice were harvested at 10, 20, and 30 days after seeding of IRG. As the harvest time of rice became later, the number of tillering before winter was reduced and IRG plant length before winter was shorter. The dry matter yield of IRG was also reduced. When rice were harvested at 20 days and 30 days after sowing of IRG compared to the rice harvested in autumn at 10 days after sowing of IRG, the number of tillering for IRG before winter was decreased by an average of 19% and 40%, respectively. The winter survival ratio of IRG was decreased by an average of 13% and 19%, respectively. Their dry matter yields were also reduced by an average of 8% and 19%, respectively. The heading date was different from each other in three years. The plant length at the time of IRG harvest in the spring was not significantly different among treatment groups. Taken together, our results suggest that when Italian ryegrass is grown in paddy fields by the method of 'seeding of IRG before rice harvest', rice should be harvested as soon as possible after sowing of IRG 'Kowinearly' in the autumn to increase forage productivity.

• 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.