• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.2
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• pp.13-35
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• 2017

This study was carried out to analyze vegetation structure and change of the disturbed area in forest ecosystem(FE), riparian ecosystem(RE) and coastal ecosystem(CE) related to Regional Ecological Network at Chungnam province through constancy and dominance analysis, species diversity index, similarity index and canonical correlation analysis. Data were collected from April to October in 2015. As a result of constancy and dominance analysis of forest disturbed area, non-effective species(NES) was 30 species(17.0%), exported species(ES) was 98 species(55.7%) and imported species(IS) was 48 species(27.3%) among the total 176 species, respectively. In riparian disturbed area with total 139 species, there were 16 NES(11.5%), 98 ES(70.5%) and 25 IS(18.0%) respectively. In coastal disturbed area with 140 species, there were 20 NES(14.3%), 88 ES(62.9%) and 32 IS(22.9%) respectively. In all types of disturbed areas, the ratio of ES was higher than IS. As a result of species diversity, species richness and shannon's diversity index of disturbed area decreased in all kinds of crown strata such as tree, subtree, shrub and herb layer compared to the control area. As a result of similarity index, that of each type between control site and disturbed site was 0.374 in FE, 0.329 in CE and 0.259 in RE in the order. As a result of the CCA analysis, the number of present species, vine plants ratio and exported species ratio in disturbed area of FE and RE were decreased, and the naturalized plant ratio, imported species ratio and herb ratio were increased. But environmental factors of CE were not shown any clear tendency. In conclusion, many species occupied in control site disappeared into the disturbed area, and the naturalized plants and herb species were abundantly imported in the area. Therefore, it was considered that this study could be applied to the development of long-term and short-term ecological restoration techniques in view of vegetation changes.

• Korean Journal of Agricultural Science
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• v.6 no.1
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• pp.1-14
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• 1979

Selection index methods were applied to selecting better performing rice varieties with better plant characters from rice yielding trials tested under six different cultural methods. The results obtained were summarized as follows: 1. Varieties such as NO. 3, 4, 5 and 6 were selected as best performing varieties with good plant and grain characters. 2. Selection index I computed from Hazel's method was appeared effective for selecting rice varieties grown under general optimum environmental conditions, while selection index II computed from Pesek and Baker's desired genetic gain were effective for selecting rice varieties grown under rather stressed conditions. 3. The rank of mean yield of each variety was not completely in agreement with that of index values, which indicates the importance of other characters besides yield in selecting varieties. 4. Most characters studied were high in broad sense of heritabilities. 5. No significant interaction was found between varieties and cultural methods.

• Applied Biological Chemistry
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• v.25 no.3
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• pp.150-154
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• 1982

Top-dressing pot experiment with $^{15}N$ urea was carried out by using three varieties. Two-split application was much better for Tongil line than 4-split. Fertilization efficiency (Fe), use efficiency (Eu) and absorbed fertilizer nitrogen efficiency (Ef) were much greater in 2-split than in 4-split. The order of Fe followed that of Ef. Grain yield and $^{15}N$ excess % among plant parts suggest that Tonsil line uptakes fertilizer nitrogen much in early stage and retranslocated well later. The order of soil nitrogen increment in plant per fertilizer nitrogen in plant $({\Delta}Ns/Nf)$ might be an index of soil nitrogen use efficiency due to fertilizer.

• Korean Journal of Remote Sensing
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• v.37 no.4
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• pp.733-745
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• 2021

Although waxy corn varieties developed after the 1980s show differences depending on development stages and conditions, studies on the characteristics of waxy corn during the growth stage are rare. The subject of this study was a field survey and unmanned aerial vehicle (UAV) image acquisition of four waxy corn varieties cultivated in Idam-ri, Gammul-myeon, Goesan-gun, Korea. The study was conducted in four stages at intervals of two weeks after planting in 2019. The growth characteristics of each of the four varieties were analyzed using growth curves obtained based on field survey and UAV imagery data. The characteristics of each growth stage of the four varieties of corn, as assessed using normalized difference vegetation index (NDVI) and plant height (P.H.) values, were as follows. The growth model was identified as a model in which three-parameter logistic (3PL) curves reflect the growth characteristics of corn well. In particular, it was found that the variations in growth rate shown by P.H. and NDVI values clearly explain the differences between corn varieties. Among the four cultivars, growth and development first occurred at the early vegetative stage in Daehakchal, followed by Mibaek 2, Miheukchal, and finally Hwanggeummatchal. The variationsin P.H. and NDVI were achieved quickly and earlier in Daehakchal, followed by Mibaek 2, Hwanggeummatchal, and Miheukchal. It was confirmed that these results reflected the characteristics of the fast white-type varieties, while the black-type varieties were delayed, as in a previous study. These results reflect the resistance to lodging that affects the cultivation environment and the response characteristics to nutrients and moisture. It was confirmed that UAV accurately provides growth information that is very useful for analyzing the growth characteristics of each corn variety.

• Journal of Environmental Science International
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• v.23 no.2
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• pp.303-312
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• 2014

As for chemical characteristics of cultivated media waste, the total content of nitrogen, phosphoric acid, and potassium was 6.93%; organic matter content was 67.78%; pH and EC were 7.20 and 1.46 ds/m, respectively. Organic acids identified during stabilization included citric acid, oxalic acid, fumaric acid, and acetic acid, which was highest. During the stabilization of cultivated media waste, temperature decreased and pH increased on the 15th day, and the germination index was 88 after the period, indicating that at least 15 days of stabilization is needed when cultivated media waste is used for growth material of crop. As for germination characteristics, when the mixture rate of cultivated media waste was 20% and under, germination of cucumber and oriental melon was favorable without difference compared to the control plots. For lettuce and Chinese cabbage, no statistically significant difference was found when the rate was 10% and under compared to the control plots. As for seedling quality after 20 days of sowing, cucumber, oriental melon, and Chinese cabbage showed favorable growth only when the mixture rate of cultivated media waste was 10% and under; lettuce showed lower growth characteristics regardless of mixture rate when compared to the control plots. Cultivated media waste may be significantly useful for cucumber and oriental melon, but not for Chinese cabbage and lettuce.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.2
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• pp.111-116
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• 2019

The biotic stress of garlic and tobacco infected by bacteria and virus was evaluated using a thermal imaging camera in a growth chamber. The remote sensing technique using the thermal camera detected that garlic leaf temperature increased when the leaves were infected by bacterial soft rot of garlic. Furthermore, the temperature of leaf was relatively high for the leaves where the colony-forming unit per mL was large. Such temperature patterns were detected for tobacco leaves infected by Cucumber Mosaic Virus using thermal images. In addition, the crop water stress index (CWSI) calculated from leaf temperature also increased for the leaves infected by the virus. The event such that CWSI increased by the infection of the virus occurred before visual disease symptom appeared. Our results suggest that the thermal imaging camera would be useful for the development of crop remote sensing technique, which can be applied to a smart farm.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.917-926
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• 2021

Lodging rice is one of critical agro-meteorological disasters. In this study, the UAV-based multispectral imageries before and after rice lodging in rice paddy field of Jeollanamdo agricultural research and extension servicesin 2020 was analyzed. The UAV imagery on 14th Aug. includesthe paddy rice without any damage. However, 4th and 19th Sep. showed the area of rice lodging. Multispectral camera of 10 bands from 444 nm to 842 nm was used. At the area of restoration work against lodging rice, the reflectance from 531 nm to 842 nm were decreased in comparison to un-lodging rice. At the area of lodging rice, the reflectance of around 668 nm had small increases. Further, the blue and NIR (Near-Infrared) wavelength had larger. However, according to the types of lodging, the change of reflectance was different. The NDVI (Normalized Difference Vegetation Index) and NDRE (Normalized Difference Red Edge) shows dome sensitivities to lodging rice, but they were different to types of lodging. These results will be useful to make algorithm to detect the area of lodging rice using a UAV.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.4
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• pp.57-67
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• 2014

The vigor condition of trees is an important indicator for the management of urban forested area. But difficulties in how to assess the tree vigor condition still remain. Previous efforts were limited in the 1) measurement of single indicator rather than using multiple indices, 2) purpose-oriented measurement such as for air-pollution effect or specific pathological symptom, and 3) ordinal-scale evaluations by field crews 4) despite human errors based on his/her experiences or prior knowledge. Therefore, this study attempted to develop a quantitative and objective methodology for assessing tree vigor condition, by measuring multiple modules and building the profile inventory. Furthermore, the possibility and limitations were discussed in terms of schematic frames describing tree vigor condition. The vigor condition of 56 flowering cherry plants in urban park were assessed by in-situ measurements of following eight items; growth of crown(Gc), growth of shoots, individual tree volume(Vol), plant area index, woody area index, leaf area index, leaf chlorophyll content(Lc) and leaf water content(Lw). For validation, these measurements were compared with the ranks of holistic tree vigor condition, which were visually assessed using a 4-point grading scale based on the expert's knowledge. As a result, the measures of each evaluation item successfully highlighted a variety of aspects in tree vigor condition, including the states of both photosynthetic and non-photosynthetic parts. The variation in the results depending on evaluated parts was shown within an individual tree, even though the broad agreement among the results was found. The result of correlation analysis between the tested measurements and 4-point visual assessment, demonstrated that the state of water-stressed foliage of the season (Lw) or the development of plant materials since sapling phase (Vol) could be better viewed from the outer appearance of trees than other symptoms. But only based on the visual assessment, it may be difficult to detect the quality of photosynthesis (Lc) or the recent trend in growth of trees (Gc). To make this methodology simplified for the broad-scale application, the tested eight measurements could be integrated into two components by principal component analysis, which was labelled with 'the amount of plant materials' and 'vigor trend', respectively. In addition, the use of these quantitative and multi-scale indicators underlies the importance of assessing various aspects of tree vigor condition, taking into account the response(s) on different time and spatial scale of pressure(s) shown in each evaluated module. Future study should be advanced for various species at diverse developing stages and environment, and the application to wide areas at a periodic manner.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.845-853
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• 2015

The objective of this study was to predict the timing of nitrogen (N) demand through analyzing chlorophyll fluorescence (ChlF), soil-plant analysis development (SPAD), and normalized difference vegetation index (NDVI), which are positively correlated with foliar N concentration in star cluster (Pentas lanceolata). The plants were grown in potting soil under optimal conditions for 30 d, followed by weekly irrigation with five concentrations (0, 4, 8, 16, and 24 mM) of N for an additional 30 d. These five N application levels corresponded to leaf N concentrations of 2.62, 3.48, 4.00, 4.23, and 4.69%, respectively. We measured 13 morphological and physiological parameters, as well as the responses of these parameters to various N-fertilizer treatments. The general increases in Dickson's quality index (DQI), above-ground dry weight (DW), total DW, flowering rate, ${\Delta}F/Fm$', and qP in response to treatment with 0 to 8 mM N were similar to those of SPAD, NDVI, and Fv/Fm. Consistent and strong correlations ($R^2$= 0.60 to 0.85) were observed between leaf N concentration (%) and SPAD, NDVI, ${\Delta}F/Fm$', and above-ground DW. Validation of leaf S PAD, NDVI, and ${\Delta}F/Fm$' revealed that these vegetation indices are accurate predictors of leaf N concentration that can be used for non-destructive estimation of the proper timing for N-solution irrigation of P. lanceolata. Moreover, irrigation with 8 mM N-fertilizer i s recommended w hen leaf N concentration, SPAD, NVDI, and ${\Delta}F/Fm$' ratios are reduced from their saturation values of 4.00, 50.68, 0.64, and 0.137%, respectively.

• Journal of Korean Society of Forest Science
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• v.111 no.2
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• pp.311-318
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• 2022

We conducted this study to derive the site index, which is a criterion for the planting of Robinia pseudoacacia, a honey plant, and to investigate the diameter distribution change by derived site index. We applied the Chapman-Richards equation model to estimate the site index of the Robinia pseudoacacia stand. The site index was distributed within the range of 16-22 when the base age was 30 years. The fitness index of the site index estimation model was low, but we judged that there was no problem in the application because the residual distribution of the equation had not shifted to one side. We used the Weibull diameter distribution function to determine the diameter distribution of the Robinia pseudoacacia stand by site index. We used the mean diameter and the dominant tree height as independent variables to present the diameter distribution, and our analysis procedure was to estimate and recover the parameters of the Weibull diameter distribution function. We used the mean diameter and the dominant tree height of the Robinia pseudoacacia stand to show distribution by diameter class, and the fitness index for dbh distribution estimation was about 80.5%. As a result of schematizing the diameter distribution by site indices as a 30-year-old, we found that the higher the site index, the more the curve of the diameter distribution moved to the right. This suggests that if the plantation were to be established in a high site index stand, considering the suitable trees on the site, the growth of Robinia pseudoacacia woul d become active, and not onl y the production of wood but al so the production of honey would increase. We therefore anticipate that the site index classification table and curve of this Robinia pseudoacacia stand will become the standard for decision making in the plantation and management of this tree.