• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.143-147
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• 2000

This study was conducted to investigate suitable seeding rate under irrigation water-saving rice culture in ridge direct seeding on dry paddy during 1997~1998. Dongjinbyeo was seeded from 60 kg/ha to 120 kg/ha on silty loam condition. The number of irrigation from 3-leaf stage to complete drainage were 7.5 times and total amount of irrigation was 258.75 mm. The number of seedling stand rose with the increase of seeding rate, whereas the rate of seedling stand was decreased with the increase of it. Soil moisture tension was -2kPa at one day after stopped irrigation and lowered to -30kPa at five days after stopped irrigation. Leaf area index and shoot dry weight were increased with rising of seeding rate. Lodging index was increased with the rising of seeding rate, but lodging was not showed in field. Heading date, percent ripened grain and 1,000 grain weight had no difference with seeding rate, and number of spikelets per m$^2$ were highest at the rate of 100 kg/ha. Rice yield was increased by 9% at the seeding rate of 100 kg/ha and 4% at the rate of 80 kg/ha and 120 kg/ha compared with 60 kg/ha. Therefore, it was considered that appropriate seeding rate was 100 kg/ha under water-saving culture in ridge direct seeding on dry paddy.

• Journal of Integrative Natural Science
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• v.7 no.3
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• pp.214-218
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• 2014

The main objective of this study is to analyse the influence factors of snowfall enhancement by glaciogenic seeding in a mountainous area. Twenty-five seeding experiments have been conducted during the period of February to April 2010. To use two rates seeding experiments (SR1: $1.04g\;min^{-1}$, SR2: $2.08g\;min^{-1}$) have been tested to get an appropriate ratio for snowfall enhancement at Daegwallyeong area. The conditions of seeding are able as followings: surface temperature <$0^{\circ}C$, wind speed <5 m/s, wind direction between 0 and $130^{\circ}$. The experiment results indicated that in the case of SR1 was more effective than SR2. The number of small ice particles below 1.0 mm was increased during seeding period measured by PARSIVEL disdrometer near generator. Most of snowfall enhancement by seeding was observed the inflow of the easterly wind blew in toward Gangwon regions from the East Sea and the supersaturated supercooled liquid water due to orographic effect.

• Journal of Environmental Science International
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• v.31 no.2
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• pp.117-129
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• 2022

In this study, we investigated the characteristics of the meteorological and environmental conditions for a cloud seeding experiment over the Korean peninsula and estimated the available days for the same. The conditions of available days appropriate for a cloud seeding experiment were classified according to four purposes: water resources, drought relief, forest fire prevention, and air quality improvement. The average number of available days for a cloud seeding experiment were 91.27 (water resources), 45.93-51.11 (drought relief), 40.28-46.00 (forest fire prevention), and 42.19-44.60 days/year (air quality improvement). If six experiments were carried out per available day for a cloud seeding experiment, the number of times cloud seeding experiments could be conducted per year in a continuously operating system were estimated as 547.62 (water resources), 275.58-306.66 (drought relief), 241.68-276.00 (forest fire prevention), and 253.14-267.60 times/year (air quality improvement). From this result, it was possible to determine the appropriate meteorological and environmental conditions and statistically estimate the available days for a cloud seeding experiment. The data on the available days for a cloud seeding experiment might be useful for preparing and performing such an experiment.

• Journal of Korea Water Resources Association
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• v.53 no.11
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• pp.999-1013
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• 2020

Weather modification research has been actively performed worldwide, but a technology that can more quantitatively prove the research effects are needed. In this study, the seeding effect, the efficiency of precipitation enhancement in weather modification experiment, was verified using the radar data. Also, the effects of seeding material on hydrometeor change was analyzed. For this, radar data, weather conditions, and numerical simulation data for diffusion were applied. First, a method to analyze the seeding effect in three steps was proposed: before seeding, during seeding, and after seeding. The proposed method was applied to three cases of weather modification experiments conducted in Gangwon-do and the West Sea regions. As a result, when there is no natural precipitation, the radar reflectivity detected in the area where precipitation change is expected was determined as the seeding effect. When natural precipitation occurs, the seeding effect was determined by excluding the effect of natural precipitation from the maximum reflectivity detected. For the application results, it was found that the precipitation intensity increased by 0.1 mm/h through the seeding effect. In addition, it was confirmed that ice crystals, supercooled water droplets, and mixed-phase precipitation were distributed in the seeding cloud. The results of these weather modification research can be used to secure water resources as well as for future study of cloud physics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.522-527
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• 1997

To find out the optimum seeding rate in corrugated water seeded rice, field experiment was carried out at Yeongdeog Substation of the National Yeongnam Agricultural Experiment Station for two years, 1994 and 1995. A rice cultivar Donghaebyeo, was seeded on May 15 with five seeding rate from 3kg /10a to 7kg /10a. The number of seedling stand per unit area was curvilinearly increased with seeding rate. In characteristics of rice plant associated with lodging, the plant height, fresh weight per tiller, Culm wall thickness and ratio of gravity center were not significantly different among seeding rates, but the breaking strength of 4th internode was slightly decreased with increasing seeding rate and thus, lodging index was generally greater at higher seeding rate than lower seeding rate. Field lodging was observed at 1~3 degree in seeding rate of 5~7kg /10a. Panicle number per unit area was generally increase with increase of seeding rate, while ratio of ripened grain was decreased with increase of spikelet number. Milled rice yield was curvilinearly increased with seeding rate. The optimum seeding rate in the highest rice yield was 4.8kg /10a in 1994, and 4.3kg /a in 1995, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.425-431
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• 2014

Most fields in highland areas are covered with rye or hairy vetch for conservation during a fallow. However, using cover crops needs an effort to sow, and this makes top soil more vulnerable to loss due to surface disturbances. The aims of this study were to develop an automatic seeding-regulator device using a low-price, extensive-use GPS sensors and a DC motors and to evaluate a working efficiency of it after adaptation to partial tillage machine for reducing seeding effort. The amount of runoff water and soil loss was evaluated with partial tillage and simultaneous-seeding after harvesting soybean, in 17% slope lysimeters. In results, the seeding amount with the machine speed was stable between $0.5{\sim}0.8m\;s^{-1}$ of working sections. The automatic control device of seeding-rate could be enough to solve the slip problems of power selecting supply system or five four-wheel drive device. In partial tillage and simultaneous seeding, runoff water was 11.6% ($1.8m^3ha^{-1}$) of the scatter-seeding control ($15.5m^3ha^{-1}$) and soil loss was 13.2% ($7kg\;ha^{-1}$) of the scatter-seeding control ($53kg\;ha^{-1}$). These results suggest that partial tillage and simultaneous-seeding methods are very effective in decreasing work effort and soil loss of sloped land.

• Journal of Environmental Science International
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• v.30 no.12
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• pp.1027-1039
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• 2021

In this study, we investigated the optimal meteorological conditions for cloud seeding using aircraft over the Korean Peninsula. The weather conditions were analyzed using various data sources such as a weather chart, upper air observation, aircraft observation, and a numerical model for cloud seeding experiments conducted from 2018 to 2019 by the National Institute of Meteorological Sciences, Korea Meteorological Administration. Cloud seeding experiments were performed in the seasons of autumn (37.0%) and winter (40.7%) in the West Sea and Gangwon-do. Silver iodide (70.4%) and calcium chloride (29.6%) were used as cloud seeding materials for the experiments. The cloud seeding experiments used silver iodide in cold clouds. Aircraft observation revealed relatively low temperatures, low liquid water content, and strong wind speeds in clouds with a weak updraft. In warm clouds, the cloud seeding experiments used calcium chloride. Observations included relatively high temperatures, high liquid water content, and weak wind speeds in clouds with a weak updraft. Based upon these results, we determined the comprehensive meteorological conditions for cloud seeding experiments using aircraft over the Korean Peninsula. The understanding of optimal weather conditions for cloud seeding gained from this study provide information critical for performing successful cloud seeding and rain enhancement.

• Atmosphere
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• v.29 no.5
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• pp.609-614
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• 2019

Cloud seeding experiment has been proposed as a way to alleviate severe air pollution problem because, if successful, artificially produced precipitation through cloud seeding could scavenge out some portion of air pollutants. As a first step to verify the practicality of such experiment, seedability of the clouds observed in Seoul is assessed by examining statistical characteristics of some relevant meteorological variables. Analyses of 9 years of Korea Meteorological Agency Seoul station data indicate that as PM₁₀ mass concentration increases, cloud amount, liquid water path, and ice water path decrease, but the difference between temperature and dew point temperature tends to increase. Such finding suggests that cloud seeding becomes less feasible as air pollution becomes more severe in the Seoul metropolitan area, at least in a statistical sense. For some individual severe air pollution events, however, seedable clouds may exist and indeed cloud seeding experiments can be successful. Therefore, detailed investigation on cloud seedability for individual severe air pollution events are highly required to make a concrete assessment of cloud seeding as a way to alleviate severe air pollution problem.

• The Korean Journal of Food And Nutrition
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• v.31 no.5
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• pp.577-586
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• 2018

The proximate compositions, quality and physicochemical characteristics of mung-bean cultivars cultivated in the north-central region of South Korea with different seeding periods were evaluated. A significant difference was noted in the proximate compositions and chromaticity of mung-beans according to cultivars and different seeding periods. Crude ash and protein content decreased with the delay in seeding period and a slight increase in carbohydrate content was observed. Redness of the other five cultivars increased with the delay in seeding period except for the cultivar Jangan, while the yellowness decreased in cultivars Geumsung and Jangan. Water binding capacity of the $1^{st}$, $2^{nd}$ and $3^{rd}$ seeding on the cultivar Eoul was 115.15, 99.76 and 96.31%, respectively, and a decrease in the binding capacity was observed with the delay in seeding periods. Water solubility index and swelling power were significantly different among cultivars. Total polyphenol content of $1^{st}$ and $2^{nd}$ seeding on the cultivar Jangan was 8.59 and 8.57 mg GAE/g, respectively, and a decrease was observed with the delay in seeding periods except for the cultivar Sohyeon. Total flavonoid content of $1^{st}$ seeding on the cultivar Jangan was 5.25 mg CE/g, which decreased with the delay in seeding periods. DPPH radical scavenging activity of $1^{st}$ seeding on the cultivars Geumsung and Kyungseon was 2.44 and 2.32 mg TE/g, respectively, which decreased with the delay in seeding periods. The BTS radical scavenging activity of $1^{st}$ seeding on the cultivar Jangan was 6.98 mg TE/g. In the present study, the variations in phenol content and radical scavenging activity were observed to be dependent on the cultivars and seeding periods.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.252-257
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• 2010

The experiments were carried out to develop ecological weed control system in wheat field of rice-wheat cropping system. The results were, depression effect on water foxtail by wheat seeding method decreased the seeding after doing soil rotary by 85% compared with the no practices. The occurrence of Water foxtail was 40 piece $m^{-2}$ on October 16, 29 piece $m^{-2}$ on October 26, and 4 piece $m^{-2}$ when surveying based on the standard of seeding the wheat at 15kg $ha^{-1}$ which decreased as the seeding time got later. According to the wheat seeding quantity 29 piece $m^{-2}$ occurred at 150kg $ha^{-1}$, and 8-11 piece $m^{-2}$ decreasingly at more than 200 kg $ha^{-1}$ of wheat seedlings based on seeding on October 26. As a result of summarizing the above results, crushing the soil by use of rotary before seeding wheat against the end of October, and seeding by increasing the seedling quantity (200 kg $ha^{-1}$) it is judged that the competition damage by weeds including water foxtail can be reduced without any use of herbicide.