• Journal of Food Hygiene and Safety
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• v.25 no.2
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• pp.91-99
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• 2010

Two pesticides commonly used in spinach were subjected to a field residue trial to ensure safety of terminal residues in the harvest. The residual patterns of two pesticides, which were Azoxystrobin and chlorpyrifos were examined after applying with the recommended dose and their $DT_{50}$ were calculated. Also degradation patterns of pesticides at storage $4^{\circ}C$ were compared to those at $20^{\circ}C$, and removal rates of pesticides by washing spinach with water were measured. Biological half-lives of azoxystrobin and chlorpyrifos were 3.2~3.8 and 3.8~4.7 days, respectively. During the storage period, the degradation patterns were appeared more obviously at $20^{\circ}C$ than $4^{\circ}C$. Removal rates of azoxystrobin and chlorpyrifos were 9.6~90.0% and 17.7~85.8% by various washing methods.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.183-188
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• 2004

This study was conducted to investigate the effects on the growth and yield by the different seeding methods and cultivating root weight in Atractylodes macrocephata Koidz. Seeding distances were different such as 5${\times}$5 cm, 5${\times}$10 cm, 10${\times}$10 cm, 10${\times}$15 cm by the hand seeder and 15 cm seeding in drill. Emergence date, plant height were not significantly changed with seeding space, but the number of leaf, fresh weight of above-ground part and fresh weight of root were increased in the sparse seeding compared with the dense seeding. The highest fresh root yield was 1,012 kg/10 a at the 5${\times}$5 cm. Roots yield was increased in the sparse seeding compared with the dense seeding, but the highest number of roots above 16 g yield was observed at the 10${\times}$10 cm seeding distance. Emergence date was faster 1∼3 day root weight above 6 g than that root weight 5 g. The plant height, number of stem and fresh weight of above-ground part were more increased as the root weight was heavier. The growth of underground part were more increased as the root weight was heavier, yield was increased about 27％ to 112％ compared with root weight above 6 g than that 134.6 kg/10 a with root 5 g.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.1
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• pp.16-22
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• 2013

Water is the most important resource for the maximum water use efficiency and yield of maize. Water has to be applied moderately based on the water requirement of maize. Crop water requirement (WR) is a function of the potential evapo-transpiration (PET) and crop coefficient (Kc). PET can be estimated by the climate data measured at the weather station in the production region. Kc was measured by the NIAST (RDA) through lysimeter experiments. In this study, the growth stage of maize was divided into five ones (G-1: Apr. 25 ~ May 20, G-2: May 21 ~ Jun. 20, G-3: Jun. 21 ~ Jul. 20, G4: Jul. 11 ~ Jul. 25, G5: Jul. 26 ~ Aug. 20). The average PET during maize growing season of the 45 areas was 2.85 mm $day^{-1}$. The highest water requirement was at the G-3 stage among the maize growth stages. The mean water requirement (MWR) according to growth stage was 1.74 ~ 2.42 (average 2.02), 2.99 ~ 4.21 (average 3.41), 3.82 ~ 5.25 (average 4.41), 3.05 ~ 4.31 (average 3.48), and 2.62 ~ 3.49 (average 3.01) mm $day^{-1}$ in the G-1, G-2, G-3, G-4 and G-5 stage, respectively. The total water requirement (TWR) according to growth stage was 45.37 ~ 63.04 (average 52.56), 92.54 ~ 130.59 (average 105.77), 76.46 ~ 105.09 (average 88.14), 45.73 ~ 64.67 (average 52.20), and 68.25 ~ 90.75 (average 78.33) mm in the G-1, G-2, G-3, G-4 and G-5 stage, respectively.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.2
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• pp.68-75
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• 2017

Demand for dwarf mondo grass (DMG; Ophiopogon japonicus 'Nanus') as an ornamental garden plant is expected to grow in the future. The purpose of this study was to investigate the levels of shade tolerance and ground cover by growing DMG under a variety of shade conditions for 18 months (May 2015~October 2016). DMG plants grown in bare ground for 3 years in Jangheung-gun, Jeonnam were used for testing. In an experimental site created in Naju city in Jeonnam, the DMG was planted in planters ($70cm{\times}70cm{\times}24cm$) and covered with a shading curtain to block natural light. Shaded conditions were then arranged under different levels of shade (0%, 55% and 75%). When the plants were grown, growth (leaf size, the number of leaves, fresh weight and dry weight) and ground coverage of DMG were analyzed. According to the results, DMG growth in terms of leaf size and the number of leaves was statistically higher under zero shade (full sunlight), when compared to other shaded conditions. DMG's fresh and dry weights were significantly greater under 0% and 55% shade, compared to those under 75% shade. The degrees of shade tolerance required for normal growth of DMG were found in the range of 0~50%, meaning that more than 50% shade may decrease plant growth. There were no statistical differences in ground coverage rates of DMG under different levels of shade. When 220 tillers were planted per $1m^2$ of plot, up to 80% of the area was covered by DMG after 18 months. Since DMG requires nutrient-rich soil to grow, sufficient nitrogen fertilizers are proposed to accelerate the ground cover of DMG. As DMG remained alive over the winter in the experiments, this study also suggests that DMG can be planted in the southern temperate region.

• FLOWER RESEARCH JOURNAL
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• v.18 no.3
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• pp.216-219
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• 2010

An Asiatic lily cultivar 'Yeri' was developed in 2005 at National Institute of Horticultural and Herbal Science (NIHHS), Rural Development Administration (RDA), Korea. The cross was made in 1993 between Asiatic lily 'Geneve', a light pink colored cultivar, and 'Montreux', deep purple colored cultivar. The first selection was done and was tentatively named as 'A95-68' in 1995. After in vitro multiplication and bulbing production, growth and flowering characteristic tests were conducted from 1996 to 2003. The evaluation of characteristics was performed and named as 'Wongyo C1-19' in 2005 that was registered as 'Yeri' to the registration office of Korea Seed & Variety Service. 'Yeri' flowered at the first of July and grew average 34.6 cm stem in length. Flowers bloomed facing upward, unspotted in petals and deep purple (RHS, RP58A). The size of flower was 13.3 cm. Mean petal length and width was 7.7 cm and 2.7 cm, respectively. Leaves were 5.1 cm long and 0.5 cm wide, respectively. The weight and size of bulb were 9.6 g and 11.7 cm, respectively. Year-round flowering can be done by storing the bulb under $-1.5^{\circ}C$ conditions. For forced cultivation, it was necessary to add calcium to the fertilizer or remove side scales to prevent leaf scorch. It was needed to control Botrytis disease in wet season.

• Korean Journal of Breeding Science
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• v.42 no.3
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• pp.218-221
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• 2010

'Anyu', a perilla (Perilla frutescens (L.) Britton) cultivar for edible seed was developed by the Department of Functional Crop Science, National Institute of Crop Science, RDA in 2008. It was originated from the cross between a pedigree of YCPL1824 as a female and SF9225-3-1 as a male parent in 1998. 'Anyu' can be characterized by purple flower color and brown grain color. 'Anyu' showed semi-dwarft type with 120 cm height, and has lodging tolerance. Maturing date of 'Anyu' was September 24, which is 15 days faster than that of 'Saeyeopsil'. The early maturity of this new cultivar showed a great advantage to various planting system with other crops. This new cultivar has high oil content (45%) and high linolenic acid in the fatty acid composition. The yield potential of 'Anyu' was about 0.9 ton/1ha in the regional yield trial.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.3
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• pp.163-168
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• 2021

The growth experiment under shading condition has been performed to understand the eco-physiological responses of crops to light in terms of photosynthesis. There are two types of shading: overall shading and partial shading. In this study, the chlorophyll fluorescence of soybean was observed under the overall shading of the box made by polyresin and the partial shading at agrivoltaic system. The overall shading condition during vegetative growth induced lower SPAD and Electron transport rate (ETR). These lower values recovered after removal of shading box. However, the Non-photochemical fluorescence quenching (NPQ) became lower under overall shading and higher under partial shading. Such increase in NPQ limited crop photosynthesis even though the ETR was almost same to the control without shading treatment. Under the condition of partial shading, the values of SP AD and ETR for soybean did not change. However, the NPQ was higher than control condition. This suggests that the crop photosynthesis under both types of shading would be decreased by different eco-physiological processes which are the lower ETR in overall shading and the higher NP Q in partial shading despite the reduced light under shading conditions.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.1
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• pp.1-14
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• 2021

Onions are a representative produce that requires supply-demand control measures due to large fluctuations in production and price by growing season. Accurate forecasts of crop production can improve the effectiveness of such measures. However, it is challenging to obtain accurate estimates of crop productivity for onions because they are mainly grown on the open fields. The objective of this study was to perform the empirical analysis of the relationship between factors for crop growth and meteorological conditions, which can support the development of models to predict crop growth and production. The growth survey data were collected from open fields. The survey data included the weight of above ground organs as well as that of the bulbs. The estimates of meteorological data were also compiled for the given fields. Correlation analysis between these factors was performed. The random forest was also used to compare the importance of the meteorological factors by the growth stage. Our results indicated that insolation in early March had a positive effect on the growth of the above-ground. There was a negative correlation between precipitation and the growth of the above-ground at the end of March although it has been suggested that drought can deter the growth of onion. The negative effects of precipitation and daylight hours on the growth of the above-ground and under-ground were significant during the harvest period. These meteorological factors identified by growth stage can be used to develop models for onion growth and production forecast.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1231-1244
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• 2022

The frequency of exposure of field crops to stress situations is increasing due to abnormal weather conditions. In South Korea, large-scale diseases in representative paddy rice cultivation area were happened. There are limits to field investigation on the crop damage due to large-scale. Satellite-based remote sensing techniques are useful for monitoring crops in cities and counties, but the sensitivity of vegetation index measured from satellite under abnormal growth of crop should be evaluated. The goal is to evaluate satellite-based normalized difference vegetation index (NDVI) retrieved from different spatial scales using drone imagery. In this study, Sentinel-2 and Landsat-8 satellites were used and they have spatial resolution of 10 and 30 m. Drone-based NDVI, which was resampled to the scale of satellite data, had correlation of 0.867-0.940 with Sentinel-2 NDVI and of 0.813-0.934 with Landsat-8 NDVI. When the effects of bias were minimized, Sentinel-2 NDVI had a normalized root mean square error of 0.2 to 2.8% less than that of the drone NDVI compared to Landsat-8 NDVI. In addition, Sentinel-2 NDVI had the constant error values regardless of diseases damage. On the other hand, Landsat-8 NDVI had different error values depending on degree of diseases. Considering the large error at the boundary of agricultural field, high spatial resolution data is more effective in monitoring crops.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.229-238
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• 2022

Animal pollination is an important ecosystem service provided mostly by diverse insect groups such as bees and hover flies. Maintaining agricultural productivity and securing the nutritional balance are closely tied to human wellbeing. This study aimed to estimate the pollination dependent food production in Korean agricultural system. Crop production data were obtained from Korean statistical information service (KOSIS) data of 2015. By implementing pollination dependency, crop production and market price, contribution of insect pollination to crop production increase were estimated from total 71 crops including 12 cereals, 19 fruits, 18 field vegetables, 13 greenhouse vegetables and 9 specialty crops. Mean pollination dependency of all crops were 29.2% and it was higher on fruits, specialty crops and greenhouse vegetables as well, but low (7.5%) in cereal crops. Pollination dependent (PD) production was estimated as 17.8% of total agricultural crop production with the economic value of 6,850 (6,508-7,193) billion won. Especially, PD production of greenhouse vegetables accounted 49.2% followed by fruits of 42.9%. Even specialty crop also showed higher PD production (35.9%). It was obvious that pollination is the vital service for agricultural production as well as nutritional security in Korea. Further protection and enhancing the pollination service were discussed with integrated pollinator-pest management (IPPM) strategies.