• Journal of Bio-Environment Control
• /
• v.26 no.3
• /
• pp.167-174
• /
• 2017

To identify the appropriate irrigation level for Pinus densiflora, a common reforestation species in Korea, we investigated their growth response characteristics according to different irrigation treatment levels for producing container seedlings with relatively high growth rate for higher survival rate when planted at the reforestation site. The container seedlings including control seedlings (no irrigation was applied) were grown in 104-cell trays were irrigated for 8 weeks from 15 weeks after seeding, at intervals of 1, 2, 3, 5, 7, 10, and 15 days. Analysis of the height growth, root collar diameter growth, and dry matter production of the container seedlings according to irrigation showed that the highest growth reaction was observed for the irrigation interval of 1 day. A shorter irrigation cycle resulted in better growth of the container seedlings, but overall, longer total root length were observed with an irrigation cycle of 3 days compared with cycles of 1 or 2 days. Quality index (QI) was the highest for the irrigation interval of 1 day, and tended to decrease with increase in the irrigation interval. Thus, it was determined that irrigation at intervals of 1-2 days was appropriate for growing Pinus densiflora container seedlings.

• The Korean Journal of Quaternary Research
• /
• v.5 no.1
• /
• pp.1-13
• /
• 1991

The distribution of cryophilous arctic-alpine and alpine plants in Korea is reviewed in connection with palaeoenvironment, along with a discussion to their origins, patterns of migration, and their refugia. At present, the estimated number of Korean arctic-alpine and alpine species is 419, and this includes 75 arctic-alpine species, 239 alpine species and 105 Korean endemic alpine species. The disjunctive distribution of cryophilous arctic-alpine and alpine plants is likely to be due to first, the downslope and southward expansion of those species towards the Korean peninsula as a primary refugia from the arctic region as the Pleistocene glacial phases approached, and then their subsequent isolation upslope in mountain areas toward a secondary refugia as the interglacial and post-glacial climatic ameliorations followed; secondly, the expansion of forest tree communities on lowland and montane areas subsequent to the end of the Pleistocene has had the effect of dividing formerly high mountains as a result of the increased competition; and thirdly, the general disapperance or restriction of available habitats for arctic-alpine and alpine species because of post-glacial climatic amelioration. The existence of 139 alpine species exclusively in the north of Korea may be due to the following reasons; first, frequent exchanges of alpine floras with other neighbouring East Asian regions would have been facilitated; secondly, there are numerous high mountains available for the alpine plants to survive and prosper during the post-glacial period; thirdly, the existence of easy accesses between mountains within the north, which has enabled alpine floras to migrate when necessary; and finally, the availability of diverse environments and habitats for the alpine flora of the north. However, the continued survival of those species in Korea at the world's or East Asia's southernmost limits of their distribution for many species is in danger if global warming associated with the greenhouse effect takes place.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.69 no.3
• /
• pp.145-153
• /
• 2024

Crop damage is becoming increasingly prevalent because of the impact of climate change-induced abnormal weather conditions. This is particularly evident in the delayed rooting of transplanted rice, caused by insufficient solar radiation. This delay in rooting negatively affects crop growth, resulting in reduced yield and delayed development. To investigate the effects of shading and elevated temperatures during rooting stage on the early growth of transplanted rice seedlings, seedlings that had been cultivated for 15 days were transplanted into a greenhouse and subjected to varying levels of shading, including 0%(control), 34%, 44%, and 70%. The height of transplanted seedlings increased under 34% shading but decreased under 44% or more shading compared to that of the no shading treatment. As the degree of shading increased, the stem diameter and root length of the seedlings decreased significantly inhibiting growth, dry matter weight, and seedling quality. Additionally, shading increases the nitrogen content of plants because of the absence of soluble carbohydrates, thereby weakening them. The adverse effects of shading on plant growth was further exacerbated by high temperatures. These findings suggest that inadequate, sunlight and elevated temperatures during rooting stage, subsequent to transplanting, may result in delay plant development and decreased resistance of the seedlings to pests and environmental challenges. Therefore, it is essential to develop innovative cultivation management techniques during the rooting stage to improve growth outcomes.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.29 no.4
• /
• pp.153-162
• /
• 2024

The number of Ecklonia cava (E. cava) populations has been gradually declining due to natural and anthropogenic effects. Although many studies have been focused on ecological phenomena, there are little studies on chemical and isotopic characteristics of natural and transplanted E. cava. Here, we collected natural and transplanted E. cava in East Sea, and measured elemental and strontium isotope geochemistry (⁸⁷Sr/⁸⁶Sr ratios) in order to provide a powerful tool for classifying them. Elemental abundances of each E. cava follow the order of stipe (2.90% ± 3.17%) > blade (2.65 ± 2.98%) > holdfast (2.30 ± 2.04%), while those of ⁸⁷Sr/⁸⁶Sr ratios do the order of blade (0.709198 ± 0.000013) > stipe (0.709181 ± 0.000009) ≈ holdfast (0.709181 ± 0.000017). All E. cava have ⁸⁷Sr/⁸⁶Sr ratios higher than that of seawater, indicating they uptake Sr from rocks and cement with higher ⁸⁷Sr/⁸⁶Sr ratios. The results of t-test showed that there is little difference in elemental compositions between two populations (p value > 0.05, n = 30), while the difference in ⁸⁷Sr/⁸⁶Sr ratios is significant (p value < 0.05, n = 30). This study suggests that the ⁸⁷Sr/⁸⁶Sr ratios can be a useful tracer for classifying natural and transplanted E. cava.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.2
• /
• pp.142-150
• /
• 2020

This experiment was conducted to set ideal harvest time for itallian ryegrass (IRG) seed in reclaimed land. For IRG 'Kowinearly' variety sown in both autumn and spring, the peak growth in reclaimed land occurred in 20-30 days after heading. Plant height of IRG seedings in the spring was 90.4% of the fall-sown's plants. The yield of IRG seeds in reclaimed land was generally lower than that of farm land due to poor growth conditions. After heading, the lodging and shattering increased gradually with time. The highest yield of seed in the fall-sown trial treatment was 238 kg/10a. However, in the spring-sown treatment, the highest yield reached 169 kg/10a, which was 71% that of the fall-sown treatment. To set optimum harvesting time for IRG seed, morphological changes in the plant, moisture content of seed, and germination rate were analyzed according to time series after heading. After heading, IRG stem color had turned pink in 18 days and seed color also changed after 20 days. Following 20-25 days after heading, the seed moisture content decreased to below 55% and germination rate increased to over 90%. Therefore optimum harvesting time for IRG 'Kowinearly' variety in reclaimed land was 20-30 days after heading because germination rate and yields were high and shattering percentage was low.

• Weed & Turfgrass Science
• /
• v.2 no.1
• /
• pp.55-61
• /
• 2013

This study was carried out to investigate the morphological and soil characteristics of Zoysia spp. native to South Korea. Samples [41 ecotypes of Zoysia japonica, 28 ecotypes of natural hybride between Z. japonica and Z. sinica (Junggi), 22 ecotypes of Z. sinica, and 8 ecotypes of Z. matrella] were collected in seashores, levee and summit of the rock in southern Korea. Variations in leaf width, plant height, leaf angle, length of leaf sheath, leaf trichome, stolon length, and seed shape were measured at collection sites and experimental plots. Among the entries, most of the measurements did not show any significant differences between natural and experimental plot except for leaf angle of Z. sinica and the number of seeds per spike of Z. matrella, which might be caused by different environmental conditions. Soil pH was 6.0 at the most of the collection sites. $Mg^+$ was 0.06-0.02 $cmol{_c}^+kg^{-1}$, $Mg^{2+}$ was 0.09-0.03 $cmol{_c}^+kg^{-1}$, and $K^+$ was 0.02-0.007 $cmol{_c}^+kg^{-1}$ at most zoysiagrasses growing soils.

• Korean Journal of Environment and Ecology
• /
• v.28 no.3
• /
• pp.331-341
• /
• 2014

The present study was to survey the site environment, vegetation structure and soil characteristics in the wild habitats of Wikstroemia ganpi in Goheung, Busan and Ulsan, and offers basic information for habitat conservation and restoration. Most of the wild habitats were located at altitudes between 28~242m with inclinations ranged as $0{\sim}40^{\circ}$. The canopy openness was 57.56%. The vegetation structure by the PC-ORD based on the Two Way Cluster Analysis were divided into three groups Community I(Castanea crenata-Pinus densiflora), Community II(Quercus dentata-Pinus thunbergii) and Community III (Pinus thunbergii). The species diversity was 1.3650, and evenness and dominance were found recorded as 0.8666 and 0.1333, respectively. The soil textures were silty loam and sandy loam. The average soil pH was 5.5, electric conductivity was 0.15dS/m, soil organic matter was 2.60% and available phosphorus was 4mg $kg^{-1}$. Correlation coefficients based on environmental factors, vegetation and soil analysis were showed that positive correlations between species diversity and evenness, organic matter and total nitrogen, whereas species slop degree and coverage of herb, diversity and dominance were showed negative correlations.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.62 no.3
• /
• pp.249-258
• /
• 2017

The purpose of this study was to investigate the effects of envrionmental factors on the ecological responses, yield, and quality properties and physicochemical characteristics of yacon cultivated in various regions of Korea. Experiments were carried out in eight regions from 2010 to 2013. The temperature range in Jinbu, Bonghwa, Cheolwon, and Gangneung during the growth period of yacon cultivation was $17.5-24.6^{\circ}C$. The total yield and marketable yield of tuberous root in Jinbu were 4,065 and 3,196 kg/10a, respectively. The sugar content of yacon tuberous roots comprised 0.11-0.20% fructose, 0.11-0.37% glucose, 0.39-0.68% sucrose, 0.07-0.37% reducing sugar, and 7.03-9.62% fructo-oligosaccharides. The content of fructo-oligosaccharides, which is a functional substance, was the highest in yacon cultivated in Jinbu. Based on the productivity and functional fructo-oligosaccharides, the optimum areas to cultivate yacon are Jinbu and Bonghwa, which are located in the middle-highland zone (500-560 m) and have a suitable growth temperature of $18-25^{\circ}C$. The results of the present study indicate that temperature could be the factor with the greatest influence on the root growth of yacon.

• Korean Journal of Soil Science and Fertilizer
• /
• v.20 no.3
• /
• pp.205-208
• /
• 1987

This study was conducted to find out the optimum ranges of soil physical properties for red pepper growth by characterizing the relationship of soil physical properties and plant growth. Various environmental factors and soil physico-chemical properties and red pepper growth were investigated at 94 farmers fields in red pepper-growing area. Soil texture of the red pepper fields were mainly coarse loamy covering 72% of surveyed fields. Available soil depth, plowing layer and root zone were deeper, but bulk density and hardness of soils were lower in the area where red pepper grew well. The optimum ranges of soil three phases were identified as the solid phase below 50%, liquid phase above 10% and sir phase above 20%. The various soil physical properties were closely related with plant growth of red pepper which were highly influenced in order of available depth>bulk density>plowing layer>hardness>slope.

• Korean Journal of Environmental Biology
• /
• v.27 no.3
• /
• pp.266-271
• /
• 2009

This study was about three genus of Viola: V. rossii, V. japonica, and V. dissecta var. chaerophylloides which can live together under a deciduous forest canopy. The aim of the study was to directly compare reproductive characteristics of the three species under the same environmental condition. By taking a census of the morphologically different flowers, the results indicate that all three species opened chasmogamous flowers before the canopy of forest closed, but continuously opened cleistogamous flowers after the canopy closed. Numbers of seeds in a capsule followed an ascending order from V. rossii to V. japonica. Mass of seeds followed a descending order from V. rossii to V. japonica. Both results had statistical significance. In terms of characteristics of seed production, V. rossii has been adapted more than V. japonica, and V. dissecta var. chaerophylloides under the deciduous forest.