• Journal of Wetlands Research
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• v.20 no.1
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• pp.1-13
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• 2018

Glaux maritima var. obtusifolia is distributed in very limited areas in South Korea and thus designated and protected as an endangered species. This study aimed to identify the diversity of vegetation in the Dangsa coast wetlands, the southern limit of G. maritima var. obtusifolia and to assess determinants of the vegetation and the importance of habitats. The phytosociological method of the $Z{\ddot{u}}rich-Montpellier$ School was used for vegetation classification and mathematical and statistical analyses were also conducted to analyze environmental factors and their relationship with the vegetation. The results of this study showed that there were 4 vegetation units in the Dangsa coast wetlands: Glaux maritima var. obtusifolia-Triglochin maritimum community (included three subcommunities), Puccinellia nipponica s.l. community, Beckmannia syzigachne-Isachne globosa community and Typha laxmannii-Phragmites communis community. It was also found that major determinants of the vegetation include moisture environment, soil depth, water level disturbance, vegetation height, community structure, etc. Glaux maritima was identified to grow most dominantly in the typicum subassociation of Glaux. maritima var. obtusifolia-Triglochin maritimum community, and the species compositions and dominant situations were observed to be similar to those in the southern limit in Japan, adjacent to South Korea. The assessment results indicated that the Dangsa coastal wetlands have a significant meaning from phytogeographical and syngeographical aspects, and contribute as a shelter for diverse species. It is required to establish conservation strategies to accurately determine the value of the wetlands of the Dangsa coast from various perspectives, and to protect and manage them.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.4
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• pp.199-205
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• 2001

This study was conducted to figure out temperature profiles of a partially developed paddy rice canopy, which are necessary to run plant disease forecasting models. Air temperature over and within the developing rice canopy was monitored from one month after transplanting (June 29) to just before heading (August 24) in 1999 and 2001. During the study period, the temporal march of the within-canopy profile was analyzed and an empirical formula was developed for simulating the profile. A partially developed rice canopy temperature seemed to be controlled mainly by the ambient temperature above the canopy and the water temperature beneath the canopy, and to some extent by the solar altitude, resulting in alternating isothermal and inversion structures. On sunny days, air temperature at the height of maximum leafages was increased at the same rate as the ambient temperature above the canopy after sunrise. Below the height, the temperature increase was delayed until the solar noon. Air temperature near the water surface varied much less than those of the outer- and the upper-canopy, which kept increasing by the time of daily maximum temperature observed at the nearby synoptic station. After sunset, cooling rate is much less at the lower canopy, resulting in an isothermal profile at around the midnight. A fairly consistent drop in temperature at rice paddies compared with the nearby synoptic weather stations across geographic areas and time of day was found. According to this result, a cooling by 0.6 to 1.2$^{\circ}C$ is expected over paddy rice fields compared with the officially reported temperature during the summer months. An empirical equation for simulating the temperature profile was formulated from the field observations. Given the temperature estimates at 150 cm above the canopy and the maximum deviation at the lowest layer, air temperature at any height within the canopy can be predicted by this equation. As an application, temperature surfaces at several heights within rice fields were produced over the southwestern plains in Korea at a 1 km by 1km grid spacing, where rice paddies were identified by a satellite image analysis. The outer canopy temperature was prepared by a lapse rate corrected spatial interpolation of the synoptic temperature observations combined with the hourly cooling rate over the rice paddies.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.2
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• pp.108-113
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• 1984

To find out the differences in micro-meteorological changes in the rice plant canopy at the different growing stages, Seokwang-byo, a high yielding variety, was cultivated with three planting densities of 50, 80 and 110 hills per $3.3m^2$ in 1982, and Seokwangbyo and Chucheong-byo, a local variety, were planted with a density of 80 hills per $3.3m^2$. Air temperature in plant canopies, water and soil temperatures were continuously monitored throughout the growing period. The relationship between solar radiation interception and leaf area indices at different height in the canopy also was studied. The results were as follows: 1. Air temperature in the densely planted canopy was 1 to $1.5^{\circ}C$ higher than that in the sparsely planted one at the early growing stage, but was inverted after 60 days of transplanting. The vertical distribution of temperature in the canopies showed that air temperature at 10 cm height from the ground was higher than that at 30 cm height. The temperature inversion occurred showing lower temperature at the 10 cm height than at the 30 cm height. 2. The highest temperature of a day in the canopy occurred at 14:00 to 15:00 Korean Standard Time same as that of air temperature, but approached to the solar noon time as the plants grew thick. 3. The air temperature in the canopy became higher than water temperature when the leaf area indices were 4.6 for Chucheongbyo and 5.2 for Seokwangbyo, and the light penetration ratios were 40 percents. 4. Light extinction coefficients of the 50 to 70 cm layer of the canopies were 0.3 to 0.5 but decreased at the lower layers. 5. Albedo of the canopies was 0.4 in the morning and evening while that was about 0.25 at noon. The difference in albedo between Seokwangbyo and Chucheongbyo could be recognized with the difference in leaf structure.

• Korean Journal of Environment and Ecology
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• v.34 no.4
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• pp.304-317
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• 2020

This study conducted selected two sites in Geumnamhonam and four sites in Honam-Jeongmaek for vegetation survey with consideration to the location environment and anthropogenic impacts to investigate the vegetation structures of the Geumnamhonam-Jeongmaek·Honam-Jeongmaek ridge areas. Using TWINSPAN (two-way indicator species analysis), each of the two ridge areas were categorized into seven plant communities. The differential species in the TWINSPAN technique indirectly represent the environmental factors of plant communities, and the community types of the two ridge areas were divided based on environmental factors such as altitudes above sea level, soil moisture, and disturbance. These results were in harmony with the environmental factors of the DCA (detrended correspondence analysis) axis 1. In the low-lying areas of both ridge areas, afforestation tree species such as Pinus rigida and P. thunbergii were in competition with native tree species. As such, in the low-lying areas, artificial vegetation disturbance was severe due to afforestation and development projects. In relatively highland areas, such as upper slopes, and top areas, in the ridge, the vegetation type with the dominance of Quercus mongolica, Q. variabilis, and P. densiflora was preserved well. As for differences between the two ridge areas, communities dominated by Q. mongolica were distributed widely in Geumnamhonam-Jeongmaek because of the altitudes above sea level, and the latitude of this ridge area are higher than those of Honam-Jeongmaek. On the other hand, communities dominated by P. densiflora were distributed along with communities dominated by Q. mongolica, and communities dominated by Q. variabilis appeared in Honam-Jeongmaek because it is adjacent to the south coast. In quantitative vegetation analysis such as TWINSPAN and DCA, changes in species composition and the extracting environmental factors that cause the changes are important. To that end, the removal of accidental emergent species, the establishment of an investigation plan that assumes environmental factors, and the selection of the optimal analytical method suitable for the characteristics of the survey data are necessary.

• Journal of Environmental Impact Assessment
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• v.25 no.2
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• pp.89-102
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• 2016

Damyang riverine wetland was designated as a wetland protected area in 2004; that is located in the Yeongsan river mainstream. Total 30 phytosociological releves at field studies were classified with 22 vegetation types including of 101 species (unidentified 1 species). Legends of actual vegetation map were separated by 6 types; riparian forest, substitute vegetation, synanthropic vegetation, wet meadow vegetation, open water, an area of wetland vegetation is about 35 % ($386,841.86m^2$). Results of this study area as follows. The plant society of Damyang riverine wetland was conjectured that it was formed by rapidly water environment change with installed weir on the upstream of protected area and operating of Damyang dam on top of the basin. Until recently, the terrace land on the river was used to cultivate, but that would be formed fallow vegetation scenery on riverfront caused by no cultivation after designated protected area. Paspalum distichum var. indutum community designated as invasive alien plant by Korea Ministry of Environment was widely developed and Myriophyllum spicatumunrecorded in the country as newly alien species was discovered in the study zone. The plants as lapped over developing environment for Leersia japonica must be occupied habitat of native plant species having similar niche. The various plant society in Damyang riverine wetland should be developed because of environmental changes, disturbances and damages of stream.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.132-139
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• 2018

The photosynthetic rate is an indicator of the growth state and growth rate of crops and is an important factor in constructing efficient production systems. The objective of this study was to develop a canopy photosynthetic rate model of romaine lettuce using the three variables of $CO_2$ concentration, light intensity, and growth stage. The canopy photosynthetic rates of the lettuce were measured at five different $CO_2$ concentrations ($600-2,200{\mu}mol{\cdot}mol^{-1}$), five light intensities ($60-340{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$), and four growth stages (5-20 days after transplanting) in three closed acrylic chambers ($1.0{\times}0.8{\times}0.5m$). A simple multiplication model expressed by multiplying three single-variable models and the modified rectangular hyperbola model including photochemical efficiency, carboxylation conductance, and dark respiration, which vary with growth stage, were also considered. In validation, the $R^2$ value was 0.923 in the simple multiplication model, while it was 0.941 in the modified rectangular hyperbola model. The modified rectangular hyperbola model appeared to be more appropriate than the simple multiplication model in expressing canopy photosynthetic rates. The model developed in this study will contribute to the determination of an optimal $CO_2$ concentration and light intensity with the growth stage of lettuce in plant factories.

• Korean Journal of Ecology and Environment
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• v.48 no.1
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• pp.26-31
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• 2015

This study was performed to evaluate the Ip-am wetland located in the Naejang National Park by analyzing vegetation and landscape and to suggest management plans. We carried out field survey in 2013 and analyzed aerial photos in 1976 and 2010 for landscape change. As a result, the places that were paddy fields in the past were dominated by 5 communities such as Salix koreensis Community (21.6%), Persicaria thunbergii Community (2.8%), Phragmites communis Community (1.1%), Molinia japonica Community (4.9%), Persicaria thunbergii-Molinia japonica Community (0.5%). On the other hand, the places that were upper fields in the past were occupied mostly by Rosa multiflora Community (6.8%), Humulus japonicus-Rosa multiflora Community (42.0%), Humulus japonicus Community (10.6%). In order to maintain and manage the wetland, water should be supplied continuously by making use of the six among the seven reservoirs located in the upper part through the hydrological survey should be accomplished. In addition, it was necessary to reinforce the banks for minimizing water outflow. It contributes to prevent dry peat and decrease in decomposition speed. Thus, it is hard to invade and settle of terrestrial plants and then secondary succession would be delayed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.229-235
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• 2001

The thermal and photometric properties of mulching materials modify the radiation and energy balance on the mulched soil surface and thereby change the soil temperature. The soil surface energy balances and soil temperatures under the mulching treatments of non-mulched control, recycled paper (RPM), and black polyethylene film (BPFM) were compared before and after the establishment of potato canopy. On August 30 in 1998 when potato was not emerged yet and solar radiation was 17.9 MJ $m^{-2}$${day}^{-1}$ , the net radiation of the soil surface was estimated as 10.(1, 2. 4, and 1.3 MJ $m^{-2}$${day}^{-1}$ under the control, BPFM, and RPM, respectively. The sensible and latent heat loss from the soil surface was 9.65 MJ $m^{-2}$${day}^{-1}$ in the control, most of the net radiation being lost through evaporation and convection, whereas it amounted only to 1.39 MJ $m^{-2}$${day}^{-1}$ in BPFM and 1.36 MJ $m^{-2}$${day}^{-1}$ in RPM. Therefore, the soil heat fluxes were 0.36 1.02, and 0.06 MJ m$^{-2}$ day$^{-1}$ under the control, BPFM and RPM, respectively. On September 27 when potato canopy was fully developed, the soil surface net radiation in the control was sharply decreased as compared to that of Aug. 30, whereas the net radiation of the mulched soil surfaces showed little changes. The soil heat flux was -0.01, 0.95, and 0.12 MJ $m^{-2}$${day}^{-1}$ at the soil surface under the control, BPFM and RPM, respectively. As the mulching treatments brought about such alteration of energy partitioning into the soil, the highest soil temperature was recorded in BPFM and the lowest in RMP without regard to potato canopy development. However, the soil temperature differences among the treatments become smaller when potato canopy were fully developed.

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2019.03a
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• pp.59-60
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• 2019

• Journal of Wetlands Research
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• v.17 no.1
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• pp.26-37
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• 2015

Halophyte distribution pattern and area in the Suncheon-bay and Beolgyo estuary coastal wetlands were analyzed using KOMPSAT-2 landsat images were taken in 2008 and 2009, and field investigations were fulfilled for confirming the precise boundaries of individual halophyte areas. The salt-marsh vegetation in those areas can be classified mainly into two dominant communities: Suaeda japonica-dominant and Phragmites communis-dominant communities. In order to identify sedimentary characteristics, tidal-flat surface leveling and sedimentary facies analysis had been conducted. The sedimentary facies of marsh area are mostly silty clayey and clay facies with a little seasonal change and its slope is very gentle (0.0007~0.002 in gradient). Phragmites communis and Suaeda japonica communities were distributed in the mud-flat zone between 0.7 m and 1.8 m higher than MSL (mean sea level): zone of 1.1~1.8 m in the former and zone of 0.7~1.3 m in the latter. In the Suncheon-bay estuarine wetland, on the basis of 2009 distribution, Phragmites communis-dominant and Suaeda japonica-dominant communities are about $0.79km^2$ and $0.22km^2$ in distribution area, respectively. On the other hand, Bulgyo estuarine marsh shows that the distribution areas of Phragmites communis-dominant and Suaeda japonica-dominant communities are about $0.31km^2$ and 0.031km2 in distribution area, respectively. Individual 105 and 60 dominant community areas and their distribution patterns can be well defined and indicated in the Suncheon-bay and Bulgyo estuarine marshes, respectively. The distribution pattern and area of hylophyte communities analyzed in this study based on 2008/2009 satellite images would be valuable as a base of future monitoring of salt-marsh related studies in the study area which is the most important salt-marsh research site in Korea.