• The Korean Journal of Pesticide Science
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• v.17 no.3
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• pp.178-184
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• 2013

Residual toxicity test to honeybee was conducted to evaluate an indirect effects on honeybee after planting hole application of systemic insecticides which were highly toxic to honeybee (Apis mellifera). In this study, It was applied three application rates in the planting hole by three systemic insecticides, dinotefuran GR, imidacloprid GR and clothianidin GR at planting time of tomato. Residual analysis of foliage was carried out after periodic sampling the foliage and investigated the effects of exposed honeybee on the tomato foliage. The honeybee mortality by dinotefuran residues on the foliage was shown almost 100% at 7 days after treatment and decreased 17 days after treatment. The maximum mortality of honeybee by imidacloprid residues on the foliage was 44 ~ 72%. But the effect of pesticide lasted for 18 days and then decreased. The honeybee mortality by clothianidin residues on the foliage was 100% at 7 days after treatment and decreased 14 days after treatment. A tendency of the honeybee mortality and residue in foliage showed a similar character as time goes by. The residues in tomato foliage decreased gradually after 14 days by vigorous growth of tomatoes and the toxic effect of honeybee was significantly decreased after 21 days in actual usage of the treatment.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.3
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• pp.110-119
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• 2017

The agroclimatic indices are produced by statistical analysis based on primary climate data (e.g., temperature, precipitation, and solar irradiance) or driving agronomic models. This study was carried out to evaluate how selection of daily temperature for a climate normal (1983-2012) affected the precision of the agroclimatic indices. As a first step, averaged daily 0600 and 1500 LST temperature for a climate normal were produced by geospatial schemes based on topo-climatology ($365days{\times}1$ set, EST normal year). For comparison, 30 years daily temperature data were generated by applying the same process ($365days{\times}30sets$), and calculated mean of daily temperature (OBS normal year). The flowering date of apple 'Fuji' cultivar, the last frost date, and the risk of late frost were estimated based on EST normal year data and compared with the results from OBS normal year. The results on flowering date showed 2.9 days of error on average. The last frost date was of 11.4 days of error on average, which was relatively large. Additionally, the risk of the late frost was determined by the difference between the flowering and the last frost date. When it was determined based on the temperature of EST normal year, Akyang was classified as a risk area because the results showed that the last frost date would be the same or later than the flowering date in the 12.5% of area. However, the temperature of OBS normal year indicated that the area did not have the risk of a late frost. The results of this study implied that it would be necessary to reduce the error by replacing the EST method with the OBS method in the future.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.401-407
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• 2009

This study intends to examine the influence of foliage treatment and seed treatment on the suppression of the succulent growth of tomato seedlings, and further, to clarify the proper way of suppressing the succulent growth of tomatoes. For the foliage treatment, the time and the concentration of diniconazol treatment were considered, and for the seed treatment, the soaking time was considered. As a result of examining the stem elongation of tomatoes based on the time and the concentration of diniconazol treatment, suppression of stem elongation and internodal length was found in step 1, 2, and 3. Plants absorb more quantity of a chemical when they are young, so a good chemical effect was found. In step 1, the number of suppressed nodes was 4, which was decreased to 3 in step 2 and to 2 in step 3. As a result of examining the influence of chemical tenacity on stem elongation, $5\;mg{\cdot}L^{-1}$ in step 1 and 2 showed the suppression of stem elongation after chemical treatment, but it became recovered fast after a particular time, compared with others. In step 3, the period of stem elongation suppression was short and they were recovered fast. In step 1, the effect of chemical tenacity was found for 5 weeks, but in step 2 and 3, it lasted for 4 weeks respectively. After raising seedlings was finished, they got planted and the quantity of living bodies increased fast so there was no significant difference in breeding from non-treatment.

• Korean Journal of Environmental Agriculture
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• v.18 no.4
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• pp.327-331
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• 1999

The purpose of this study was to find out the effects of slow-released nitrogen fertilizer (SRF) on the growth and yield of Chinese cabbage. The SRF used in this study was prepared by embedding urea into a waste paper slum. The underwater dissolution rate of SRF was very rapid during the first 12 hours and 60.4% of the embedded nitrogen was released after 72 hours. The SRF and urea was applied as nitrogen source and growth. yield, yield components, nitrogen uptake of Chinese cabbage were investigated a pot experiment. Maximum leaf length of Chinese cabbage was not different between SRF and urea treatments. Length and wish of head, number of leaf per head and fresh weight of Chinese cabbage were higher in SRF treatment than those in urea treatment, but the differences were not statistically significant. Comparing to the urea treatment, nitrogen content and nitrogen uptake efficiency of Chinese cabbage were significantly higher in SRF treatment. After the experiment, total soil nitrogen contents were not different between the SRF and urea treatments.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.635-641
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• 2012

The present study evaluated the effect of chitosan on the changes of soil chemical properties, soil microbial population, and yield of red pepper (Capsicum annuum L.) for eco-friendly agriculture in an upland field. We utilized four treatment groups, control, foliar spray, soil drench, and foliar spray + soil drench with chitosan, and analyzed these variations throughout the seven, fourteen, and twenty one days interval. The pH values, organic matter, and available phosphate in the upland soil at the harvesting stage decreased in the chitosan treatment. The populations of bacteria, actinomyces, and fungi in the upland field were increased in plots treated with chitosan. The chlorophyll content of leaves was no significant differences between the control and the chitosan treatments, while calcium content of leaves was significantly higher in the chitosan treatments than in the control. In addition, the nitrogen content of leaves was no significant differences between the foliar spray and the soil drench. The yield of red pepper was significantly higher in the control ($383kg\;10a^{-1}$) than the chitosan treatments and the yield of soil drench with chitosan reached up to 95% of control.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.2
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• pp.171-176
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• 2012

Purpose: This study was to compare changes in near lateral phoria and near point of convergence after viewing smartphones and monitors during short periods. Methods: 50 subjects with healthy eyes from 20s to 30s (mean age, $21.84{\pm}5.13$ years) were examined. Viewing time was set at 5 min to 20 min, and recovery time was 10 min. Near lateral phoria and near point of convergence (NPC) were examined before and after watching smartphones and monitors, and subjectively symptoms for visual fatigue were surveyed using a questionnaire before and after viewing image. Results: The tendency of phoria in viewing smartpones found more exophoric results than in viewing monitors, and both exophoric shifts were recovered after 10 min. The receded NPC in the smartphones was more remote than in the monitors. The smartpones induced more visual fatigue than the monitors. Conclusions: Sustained smartphone works induced changes in phoria and NPC, and this type of stress could cause visual fatigue. Therefore, an appropriate rest breaks can be helpful in relieving visual fatigue.

• Applied Microscopy
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• v.33 no.4
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• pp.275-282
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• 2003

This study was undertaken to investigate paraquat-induced pulmonary injuries and effects of colchicine on pulmonary fibrosis by paraquat. Fifteen Sprague-Dawley rats were intraperitoneally injected 10 mg/kg of paraquat and repeatedly with 2 days interval. Another 15 rats were injected paraquat as same manner and simultaneously injected 10 mg/kg of colchicine in a week. Five rats in each group were sacrificed 1, 2, and 4 weeks after initial injections, and lungs extracted were observed by light and electron microscopes. On light microscopy, there was mild infiltration of neutrophils, macrophages, and lymphocytes in alveolar spaces and walls at 1 week after paraquat injection. The cellularity of alveolar wall was increased with time. However, the cellularity was not so prominent in paraquat and colchicine simultaneously injected group. On electron microscopy, there was marked swelling or excoriation of type I epithelial cells and alveolar capillary endothelium with infiltration of neutrophils, macrophages and monocytes, and lymphocytes in alveolar walls. Such findings were persisted with time. In addition, fibroblastic proliferation and deposition of collagen fibers were prominent at 4 weeks after paraquat injection. Fibrosis also occurred at 4 weeks after paraquat and colchicine simultaneous injection. It was not proninent than that of paraquat injected group. According to the above result, it would be concluded that the type I pneumocytes and alveolar capillary endothelial cells are most vulnerable on paraquat poisoning, and that the colchicine is effective on inhibition of paraquat-induced pulmonary fibrosis.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.3
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• pp.177-183
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• 2008

Sodium is known to reduce a plant growth and yields. However, the relationships between physiological response of seedling and salinity stress caused by growing media are not well understood yet. We conducted experiments to investigate change of some parameters including Na, EC, moisture content in media under different air temperature ($15^{\circ}C$, $25^{\circ}C$), and the response of fruit-vegetables such as cucumber, oriental melon on saline conditions originated from horticultural substrate. Volumetric moisture content of media at $15^{\circ}C$ was 70%, but at $25^{\circ}C$ was decreased by 45% within 22 hrs, showing below optimal matric potential, approximately. During reaction time, the increase of Na concentration was significantly greater in saline substrate than in control. The decrease rate of Na concentration according to supplying irrigation water was higher in saline substrate than in control. $CO_2$ assimilation rate and transpiration rate of Korea melon grown in low temperature were decreased with a Na/cation ratio in hydroponic solution. Water saturation deficit was also increased significantly at $15^{\circ}C$ as compare to $25^{\circ}C$. Saline stress during nursery stage induced a reduction of seedling quality, growth and cucumber yield. The results suggest that the relationship between uncontrolled Na uptake of seedling from saline substrate and meteological condition is responsible for saline stress.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.122-129
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• 2002

The removal rate of heavy metals from the wastewater, the accumulation and translocation of heavy metals in plants after transplanting, and the responses of water celery growth with different wastewater treatments were investigated to determine the potential ability of green-remediation with hydroponic culture of water celery. The removal rate and translocation of Cd, Cu, Ni and Pb from different wastewater to plants were compared with cultivation periods after transplanting. The removal rate of heavy metals from wastewater was different with each treatment but increased with growing periods of water celery plants. The removal rate of Cd, Cu, Ni and Pb in Artificial solution, Artificial solution+EDTA, Munmark industrical wastewater, Jungsun minewater is ranged from 22 to 73%, from 28 to 100%, from 13 to 92% and from 41 to 100% at 6 days after transplanting, respectively. The translocations of Cd, Cu, Ni and Pb from roots to shoots in Artificial solution, Artificial solution+EDTA, Munmark industrical wastewater, Jungsun minewater are ranged from 14 to 28%. 8 to 30%. from 28 to 45% and from 2 to 15% at 12 days after transplanting, respectively. In plant growth responses, it appears to be inhibited the plant growth over all treatments excepts for Munmark industrial wastewater in these glowing periods. Therefore the water celery might play a useful role in phytoremediation to clean up wastewater contaminated with Cd, Cu, Ni or Pb.

• Journal of Fisheries and Marine Sciences Education
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• v.10 no.2
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• pp.211-225
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• 1998

A field experiment was carried out for fishes on entering time to a set-net, swimming speed, current speed and direction at the Dongbok-Ri coast on Cheju Island. The results of the experiment are as follows : 1. The observation results from 07:00 to 18:00 showed that coral fish, flying fish, horse mackerel, drub mackerel and striped mullet enter the set-net from 07:00 to 14:00 mainly. 2. From the result of analyzing relationships between entering time and tide, coral fish and horse mackerel tend to enter the set-net on turn of tidal current and ebb respectively. 3. The leaving rates of coral fish, flying fish, drub mackerel, and striped mullet from the set-net were 13%, 45%, 50%, and 100%, respectively but all horse mackerel remained in the net. 4. The swimming speed of coral fish, flying fish, horse mackerel and drub mackerel are 5~25cm/sec, 20~50cm/sec, 15~45cm/sec and 10~30cm/sec, respectively and their dominant speeds are 10~15cm/sec(55%), 30~35cm/sec(30%), 30~40cm/sec(60%), and 15~20cm/sec(60%), respectively.