• Korean Journal of Soil Science and Fertilizer
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• v.6 no.2
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• pp.95-105
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• 1973

Sink (grain)-filling rates of IR667 line (Suwon 213 and 214) and local leading varieties (Jinheung and Paldal) were investigated in relation to sink-source ratio, sink-source distance, forms of photosynthates, and weather factors. The results are as follows. 1. IR667 line have higher maximum filling rate (g. grain/day. ear) and shorter duration to reach maximum filling rate than local varieties. The curve pattern of sink-filling rate was high and steep type in IR667 line and low and broad type in local varieties. 2. Weather factors seem to give little effect on the curve pattern of sink-filling rate. 3. The functional sink-source distance (actual sink-source distance multiplied by the contribution rate of leaf for grain production) was shorter in upper leaves (flag and 2nd leaf) for IR667 line, the upper leaf-dependent type in grain production, and was longer in lower leaves (3rd and 4th) for local varieties, the lower leaf-dependent type. Specially short first internode from top may contribute to the upper leaf depencency of IR667 line. 4. According to free sugar-starch ratio (sugar/starch) in the culm and leaf sheath IR667 line could be classified as the high sugar type and the local varieties as the high starch type. The ratio of transportable form (sugar) to non transportable photosynthate (starch) seems to relate with sink-filling rate. And high sugar type is expected to have higher efficiency for grain production in view of energy balance. 5. A hypothesis that the higher in the uniformity within the series of productive structure the more efficient in grain production is proposed and discussed in relation to productivity. 6. According to the pattern of percent nutrient retention of each leaf blade IR667 showed the central retention type and Jinheung showed the apical retention type and each retention type appears to be a cause of each canopy conservation pattern. 7. From the content and percent distribution of nutrient in various organ IR667 could be classified as the leaf sheath dominant type and Jinheung as the leaf blade dominant type. 8. The fact that the greater the percent translocation of nutrient into grain the greater the percent nutrient retention in leaf blade was held between nitrogen and phosphorus within a variety and between varieties within a nutrient (N, P or K).

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.2
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• pp.85-96
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• 2019

Solar radiation is an important variable for estimation of energy balance and water cycle in natural and agricultural ecosystems. A deep neural network (DNN) model has been developed in order to estimate the daily global solar radiation. Temperature and precipitation, which would have wider availability from weather stations than other variables such as sunshine duration, were used as inputs to the DNN model. Five-fold cross-validation was applied to train and test the DNN models. Meteorological data at 15 weather stations were collected for a long term period, e.g., > 30 years in Korea. The DNN model obtained from the cross-validation had relatively small value of RMSE ($3.75MJ\;m^{-2}\;d^{-1}$) for estimates of the daily solar radiation at the weather station in Suwon. The DNN model explained about 68% of variation in observed solar radiation at the Suwon weather station. It was found that the measurements of solar radiation in 1985 and 1998 were considerably low for a small period of time compared with sunshine duration. This suggested that assessment of the quality for the observation data for solar radiation would be needed in further studies. When data for those years were excluded from the data analysis, the DNN model had slightly greater degree of agreement statistics. For example, the values of $R^2$ and RMSE were 0.72 and $3.55MJ\;m^{-2}\;d^{-1}$, respectively. Our results indicate that a DNN would be useful for the development a solar radiation estimation model using temperature and precipitation, which are usually available for downscaled scenario data for future climate conditions. Thus, such a DNN model would be useful for the impact assessment of climate change on crop production where solar radiation is used as a required input variable to a crop model.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.444-451
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• 2022

Recently, long-term cultivation is becoming more common with the increase in tomato hydroponics. In hydroponics, it is very important to supply an appropriate nutrient solution considering the nutrient and moisture requirements of crops, in terms of productivity, resource use, and environmental conservation. Since seasonal environmental changes appear severely in long-term cultivation, it is so critical to manage irrigation control considering these changes. Therefore, this study was carried out to investigate the effect of irrigation volume on growth and yield in tomato long-term cultivation using coir substrate. The irrigation volume was adjusted at 4 levels (high, medium high, medium low and low) by different irrigation frequency. Irrigation scheduling (frequency) was controlled based on solar radiation which measured by radiation sensor installed outside the greenhouse and performed whenever accumulated solar radiation energy reached set value. Set value of integrated solar radiation was changed by the growing season. The results revealed that the higher irrigation volume caused the higher drainage rate, which could prevent the EC of drainage from rising excessively. As the cultivation period elapsed, the EC of the drainage increased. And the lower irrigation volume supplied, the more the increase in EC of the drainage. Plant length was shorter in the low irrigation volume treatment compared to the other treatments. But irrigation volume did not affect the number of nodes and fruit clusters. The number of fruit settings was not significantly affected by the irrigation volume in general, but high irrigation volume significantly decreased fruit setting and yield of the 12-15th cluster developed during low temperature period. Blossom-end rot occurred early with a high incidence rate in the low irrigation volume treatment group. The highest weight fruits was obtained from the high irrigation treatment group, while the medium high treatment group had the highest total yield. As a result of the experiment, it could be confirmed the effect of irrigation amount on the nutrient and moisture stabilization in the root zone and yield, in addition to the importance of proper irrigation control when cultivating tomato plants hydroponically using coir substrate. Therefore, it is necessary to continue the research on this topic, as it is judged that the precise irrigation control algorithm based on root zone-information applied to the integrated environmental control system, will contribute to the improvement of crop productivity as well as the development of hydroponics control techniques.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.194-203
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• 2022

Cultivation of tomatoes in Korea grown in soil covers 89% of the total area for tomato cultivation. Tomatoes grown in soil often encounter various environment stresses including not only salt stress and soil-borne diseases but also cold stress in the winter season. This study was conducted to comparatively analyze the performance of rootstocks with cold stress by measuring the growth, yield, and photosynthetic efficiency in tomatoes grown in soil. The rootstocks were used 'Powerguard', 'IT173773', and '20LM' for the domestic rootstock cultivars and 'B-blocking' for a control cultivar. The tomato cultivar 'Red250' was used as the scion and the non-grafted tomatoes. Stem diameter, flowering position, leaf length, and leaf width were investigated for the growth parameters. The stem diameter of the non-grafted tomatoes decreased by 15% compared to the grafted tomatoes at 80 days after transplanting when exposed to low temperatures of 9-14℃ for 14 days. The leaf length and width of the non-grafted tomatoes were the lowest with 42.4 cm and 41.8 cm at 80 days after transplanting. The total yield per plant was the highest in tomato plants grafted on 'Powerguard' with 1,615 g and lowest in non-grafted tomatoes with 1,299 g. As the result of measuring the chlorophyll fluorescence parameters, PI_ABS and DI₀/RC, which mean the performance index and dissipated energy flux, 'Powerguard' was the highest with 3.73 in PI_ABS and the lowest with 0.34 in DI₀/RC, whereas non-grafted tomatoes was the lowest with 2.62 in PI_ABS and the highest with 0.41 in DI₀/RC at 80 days after transplanting. The stem diameter has positive correlation with PI_ABS, while it has negative correlation with DI₀/RC. The results indicate that can be analyzed by chlorophyll fluorescence parameters can be used for analyzing the differences in the growth of tomato plants grafted on different rootstocks when exposed to cold stress.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.5
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• pp.69-79
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• 2022

This study aims to assess the current understanding of the landscape of wind power facilities as renewable energy sources that supply sightseeing, tourism, and other opportunities. Therefore, social media data related to the landscape of wind power facilities experienced by visitors from different regions was analyzed. The analysis results showed that the common characteristics of the landscape of wind power facilities are based on the scale of wind power facilities, the distance between overlook points of wind power facilities, the visual openness of the wind power facilities from the overlook points, and the terrain where the wind power facilities are located. In addition, the preference for wind power facilities is higher in places where the shape of wind power facilities and the surrounding landscape can be clearly seen- flat ground or the sea are considered better landscapes. Negative keywords about the landscape appear on Gade Mountain in Taibai, Meifeng Mountain in Taibai, Taiqi Mountain, and Gyeongju Wind Power Generation Facilities on Gyeongshang Road in Gangwon. The keyword 'negation' occurs when looking at wind power facilities at close range. Because of the high angle of the view, viewers can feel overwhelmed seeing the size of the facility and the ridge simultaneously, feeling psychological pressure. On the contrary, positive landscape adjectives are obtained from wind power facilities on flat ground or the sea. Visitors think that the visual volume of the landscape is fully ensured on flat ground or the sea, and it is a symbolic element that can represent the site. This study analyzes landscape awareness based on the opinions of visitors who have experienced wind power facilities. However, wind power facilities are built in different areas. Therefore, landscape characteristics are different, and there are many variables, such as viewpoints and observers, so the research results are difficult to popularize and have limitations. In recent years, landscape damage due to the construction of wind power facilities has become a hot issue, and the domestic methods of landscape evaluation of wind power facilities are unsatisfactory. Therefore, when evaluating the landscape of wind power facilities, the scale of wind power facilities, the inherent natural characteristics of the area where wind power facilities are set up, and the distance between wind power facilities and overlook points are important elements to consider. In addition, wind power facilities are set in the natural environment, which needs to be protected. Therefore, from the landscape perspective, it is necessary to study the landscape of wind power facilities and the surrounding environment.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.40-47
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• 2023

There are many different types of cultivation in tomatoes for year-round production. One of them, semi-forcing cultivation is characterized by growing seedlings in winter season. If grafted seedlings are used in winter season that energy cost can be reduced, because they have tolerance to cold stress. This study was conducted to analyze the rootstock performance by measuring the growth, yield, and leaf-macronutrient content of cherry tomatoes grown in semi-forcing hydroponics. Three domestic rootstocks 'HSF4', '21LM', '21A701', and a control cultivar 'B-blocking' were grafted onto jujube-shaped cherry tomato (Lycopersicon esculentum L.) commercial cultivar 'Nonari'. The total yield per plant with grafted cherry tomato '21A701' was 3,387g, which was 11%, 22% and 24% higher than the yield with 'B-blocking', non-grafted one and 'HSF4'. The stem diameter of '21A701' was thick with 8.26mm, whereas non-grafted one was thin with 7.23mm at 160 days after transplanting. The flowering position of '21LM' was 34% and 47% higher than the flowering position of 'B-blocking' and non-grafted one at 153 days after transplanting. The NO₃-N concentration in petiole sap of '21LM' was the highest with 1,746mg·L^-1 and non-grafted one and 'HSF4' were the lowest with 1,252mg·L^-1 and 1,245mg·L^-1 at 167 days after transplanting. The results indicated that rootstock/scion combinations in cherry tomatoes can affect the plant growth, yield, and the concentration of different NO₃-N in leaves at the late growth stage. Both '21A701' and '21LM' have vigorous root system, which influence the growth and yield increased.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.157-164
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• 2023

Codonopsis lanceolata (S. et Z.) Trautv. is mainly cultivated in Korea and China as a medicinal crop. C. lanceolata is difficult to produce plug seedlings in the summer, because C. lanceolata has a low germination rate and is vulnerable to high temperatures. Cold treatment is effective in breaking dormancy of seeds and increasing the germination rate. Shading cultivation can control the solar irradiance received by plants and reduce the damage by high temperatures and strong light. This study was conducted to examine the appropriate cold treatment period for the improving germination of C. lanceolata, and shading level during the summer seedling period. Cold treatment experiments were conducted for 0 (control), 1, 2, 3, and 4 weeks at 4℃ before sowing. In the shading experiment, C. lanceolata was grown for 45 days with 0 (non-treatment), 45, 75% shading levels. Cold treatment for one week significantly improved the germination energy. The plant height, leaf area, and fresh and dry weights of C. lanceolata seedlings were significantly increased under the 45% shading level. Total root length, root surface area, and the number of root tips were significantly higher in shading treatment (45 and 75%) than in non-treatment. The C. lanceolata seedling's compactness and Dickson's quality index were the highest at 45% shading level. Therefore, these results recommended sowing C. lanceolata after cold treatment for one week at 4℃, and 45% shading level could stably culture C. lanceolata plug seedlings during the high temperature period.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.1
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• pp.54-60
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• 2022

The planting date of corn for silage has been delayed because of spring drought and double cropping system in Korea. This experiment was conducted to evaluate agronomic characteristics, forage production and feed value of corn at April and May in 2019. Experimental design was a split-plot with three replications. Planting dates (12 April and 10 May) were designated to the main plot, and corn hybrids ('P0928', 'P1543' and 'P2088') to the subplot. The silking days of the early planting date (12 April) was 79 days and that of the late planting date (10 May) was 66 days (p<0.0001), however, there were no significant differences among the corn hybrids. Ear height of the late planting date was higher than that of the early planting (p<0.05), while there were no significant differences in plant height of corn. Insect resistance at the early planting was lower than that of late planting (p<0.05), however, lodging resistance was no significant difference at planting date. The rice black streaked virus (RBSDV) infection of early planting was 3.7% and that of late planting was 0.3% (p<0.001). Dry matter (DM) contents of stover, ear and whole plant had significant difference at planting date (p<0.05). And differences in ear percentages were observed among the corn hybrids (p<0.01). And ear percentages of early maturing corn ('P0928') was higher than for other hybrids. Ear percentage at the early planting date was higher than that at the late planting date (p<0.01). DM and total digestible nutrients (TDN) yields had significant difference at planting date, however, there were no significant differences among the corn hybrids. DM and TDN yields at the late planting (21,678 kg/ha and 14,878 kg/ha) were higher than those of the early planting (13,732 kg/ha and 9,830 kg/ha). Crude protein content at the early planting date was higher than that of the late planting. Acid detergent fiber content of the late planting was lower than that of the early planting date (p<0.01), while there were no significant neutral detergent fiber content difference among the corn tested. Calculated net energy for lactation (NE_L) and TDN at the early planting were higher than those of at the late planting (p<0.01). Results of this our study indicate that the late planting date (May) is better than early planting date (April) in forage yield and feed value of corn. Therefore, the delay of planting date by May was more suitable for use in cropping system.

• Journal of Radiation Protection and Research
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• v.33 no.4
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• pp.183-196
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• 2008

The internal dose by food consumption mostly accounts for radiological dose of public around nuclear power plants (NPPs). But, food consumption rates applied to off-site dose calculation in Korea which are the result of field investigation around Kori NPP by the KAERI (Korea Atomic Energy Research Institute) in 1988, are not able to reflect the latest dietary characteristics of Korean. The food consumption rates to be used for radiological dose assessment in Korea are based on the maximum individual of US NRC (Nuclear Regulatory Commssion) Regulatory Guide 1.109. However, the representative individual of the critical group is considered in the recent ICRP (International Commission on Radiological Protection) recommendation and European nations' practice. Therefore, the study on the re-establishment of the food consumption rates for individual around nuclear power plant sites in Korea was carried out to reflect on the recent change of the Korean dietary characteristics and to apply the representative individual of critical group to domestic regulations. The Ministry of Health and Welfare Affairs has investigated the food and nutrition of nations every 3 years based on the Law of National Health Improvement. The statistical data such as mean, standard deviation, various percentile values about food consumption rates to be used for the representative individual of the critical group were analyzed by using the raw data of the national food consumption survey in $2001{\sim}2002$. Also, the food consumption rates for maximum individual are re-estimated.

• Korean Journal of Environmental Agriculture
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• v.15 no.1
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• pp.11-18
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• 1996

A greenhouse experiment on the Sr-90 uptake by peanut and sesame was conducted through pot cultures on a sandy loam soil of pH 6.35 treated with Sr-90 in 5.2 and 31.2Bq per gram. The rate of Sr-90 transfer from soil to each plant part, the ratio of Sr-90 concentration in the part to the concentration in soil, and the patterns of their temporal changes were not, on the whole, significantly different between the two treatments. About 0.7 and 0.5 % of Sr-90 in soil transferred to all the mature plants of peanut and sesame, respectively, with the radioactivities in their roots not counted. Only 4% and less than 15% of Sr-90 absorbed by peanut and sesame, respectively, translocated to their seeds. Both crops showed the highest Sr-90 concentration in the leaf and the lowest in the seed. At maturities, the concentration ratio in dry seed was 0.4 in peanut and 3.3 in sesame and that in dry leaf was 12.5 and 10.7, respectively. Sr-90 concentrations in the top 15 cm soil after harvests averaged about 80 % of the concentrations at starting. Sr-90 uptake resulted in neither growth inhibition nor yield decrease.