• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.95-95
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• 2022

Maize is one of the world's three largest crops and has a long cultivation history, and is an important crop used for various purposes such as food, feed, and industrial raw materials. Recently, the agricultural environment is changing, in which the limit of cultivation of crops is shifted to the north due to the rise in temperature due to climate change. This study was conducted in experimental field of Suwon in 2022 by setting a seeding period earlier than the sowing time to establish the North Korean agricultural climatic zone and meteorological conditions. The test cultivars were silage cultivars, Kwangpyeongok and Dacheongok. As a priming test method, it was used to directly plant seeds in the field through immersion using 4mM zinc (Zn) and 2.5mM manganese (Mn), which are trace elements for seeds. The planting season was early on March 15th, April 1st, and April 15th. The number of days from sowing to silk stage of the two cultivars sown on March 15, April 1, and April 15 was 107, 93, and 85 days for Kwangpyeongok and 109, 95, and 87 days for Dacheongok, respectively. The seed priming test did not show any difference from the control group in the growth survey up to the middle stage of growth. In another test, low-temperature recovery was confirmed through nitrogen (2-5%) foliar fertilization after 3 days, 5 days, and 7 days in refrigeration (0 degrees), a selective low temperature treatment for com in the third leaf stage. As a result of this study, it was confirmed that the low-temperature damaged com treated at 0℃ showed the same growth as that of the untreated com through nitrogen foliar fertilization. These results suggest that urea foliar fertilization for low-temperature damage reduction of corn for silage in high-latitude climates will be helpful. In addition, through the results of the study, additional studies are needed on the recovery mechanism and field application through urea foliar fertilization.

• The Korean Journal of Ecology
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• v.16 no.4
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• pp.515-526
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• 1993

In order to study the ecotypic variation of Rohinia pseudo-acacia L. distributed in southern area of Korean peninsula, 15 local populations(Daejin, Sokcho, Kangneung, Mt. Surak, Hongcheon, Kwangneung, Namhansanseong, Chungju, Yesan, Andong, Jeonju, Dalseong, Changweon, Mokpo and Wando), located from $34^{\circ}18'N\;to\;38^{\circ}36'N$, were selected based on the latitudes and geographical distances. Seeds of these populations were collected and protein contents of seeds and their band patterns were investigated. The seed proteins of all populations were electrophoresed on SDS-polyacrylamide gel. Total number of protein bands were 35, whose molecular weights ranged from 17, 258 daltons to 142, 232 daltons. The number of bands of seed proteins was 23 in Dalseong and Hongcheon and was 32 in Daejin and Sokcho, showing an increasing tendency in the number of bands as the latitude goes high. The local populations were classified into 3 local types based on protein analysis: the middle north east coastal type(Daejin, Sokcho. Kangneung), the central type (Mt. Surak, Hongcheon, Kwangneung, Namhansanseong, Chungju) and the southern type(Yesan, Andong, Jeonju, Dalseong, Changweon, Mokpo, Wando). According to the results of cluster analysis by UPGMA based on the similarity index(c0efficient of Jaccard) of the patterns, 3 local types were subdivided further into 6 types: the middle north east coastal type(Sokcho, Kangneung), the north central type I (Mt. Surak, Hongcheon), the north central type II (Narnhansanseong, Chungju, Daejin), the north central type III (Kwangneung), the south central type (Yesan, Dalseong, Jeonju) and the southern type(Andong, Changweon, Mokpo, Dalseong, Wando). The No. 12 band of the separated seed proteins showed the highest colored density in the preparations from all the populations. The No. 11~13 and No. 23~28 bands also showed high densities. As a whole, southern type populations (Changweon, Mokpo, Wando) showed high protein contents and high colored density. Total protein contents of the seeds in each population were variable from 9. 68mg / g (Mt. Surak) to 17.30mg/g (Jeonju), showing an increasing trends toward low latitudes.

• Korean Journal of Environment and Ecology
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• v.25 no.2
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• pp.132-144
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• 2011

We studied the forest environment and characteristics of bird community between April and September of 2010 on the Hyangjeokbong area(A), Baekryunsa area(B) and Anseong area(C), all in the Deogyusan National Park. Hyangjeokbong area of the high latitude ridge was characterized by the Taxus cuspidata and Abies koreana etc., and deciduous broadleaf forest species, such as the Quercus mongolica, with abundance of subalpine zone coniferous trees, the Hemerocallis fulva and the Rhododendron schlippenbachii, while the areas Baekryunsa and Anseong were primarily characterized by deciduous broadleaf forests, with the valleys showing Fraxinus mandshurica colonies. In terms of the DBH(diameter at breast height) of trees, between 11 and 20cm showed the highest frequencies, while over 30cm was the highest in Baekryunsa area and the lowest in Hyangjeokbong area. Furthermore, in terms of coverage in relation to layers, in Hyangjeokbong area, the coverage volume of the lower layer was very high, in Baekryunsa area, the coverage volume of the middle layer between 8 and 12m was the highest, and in Anseong area, the coverage volume of the upper layer over 18m was the highest. A total of 53 bird species were observed during the study period at the Deogyusan National Park. The numbers of species and density of areas were 25 species and 45.20 Ind./km for Hyangjeokbong area, 50 species and 58.63 Ind./km for Baekryunsa area and 35 species and 66.89 Ind./km for Anseong area, with Baekryunsa area showing the highest number of species and Anseong area showing the highest level of density. In terms of dominant species, in Hyangjeokbong area, Cettia diphone, along with species which inhabit in grassland and shrubs, were the dominant species, and species which live in the canopy layer, including the Aegithalos caudatus, were found to be dominant in Baekryunsa and Anseong areas. For guild structure, bush nesting guild and bush foraging guild species were the highest in all areas, and the hole nesting guild and the air foraging guild species showed the lowest proportion. This seems to be the result of the low number of trees with diameter at breast height of over 30cm, which results in the lack of nesting grounds for hole nesting guild species.

• Atmosphere
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• v.21 no.4
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• pp.349-359
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• 2011

The climatology in stratospheric ozone over the Korean Peninsula, presented in previous studies (e.g., Cho et al., 2003; Kim et al., 2005), is updated by using daily and monthly data from satellite and ground-based data through December 2009. In addition, long-term satellite data [Total Ozone Mapping Spectrometer (TOMS), Ozone Monitoring Instrument (OMI), 1979~2009] have been also analyzed in order to deduce the spatial distributions and temporal variations of the global total ozone. The global average of total ozone (1979~2009) is 298 DU which shows a minimum of about 244 DU in equatorial latitudes and increases poleward in both hemispheres to a maximum of about 391 DU in Okhotsk region. The recent period, from 2006 to 2009, shows reduction in total ozone by 6% relative to the values for the pre-1980s (1979~1982). The long-term trends were estimated by using a multiple linear regression model (e.g., WMO, 1999; Cho et al., 2003) including explanatory variables for the seasonal variation, Quasi-Biennial Oscillation (QBO) and solar cycle over three different time intervals: a whole interval from 1979 to 2009, the former interval from 1979 to 1992, and the later interval from 1993 to 2009 with a turnaround point of deep minimum in 1993 is related to the effect of Mt. Pinatubo eruption. The global trend shows -0.93% $decade^{-1}$ for the whole interval, whereas the former and the later interval trends amount to -2.59% $decade^{-1}$ and +0.95% $decade^{-1}$, respectively. Therefore, the long-term total ozone variations indicate that there are positive trends showing a recovery sign of the ozone layer in both North/South hemispheres since around 1993. Annual mean total ozone (1985~2009) is distributed from 298 DU for Jeju ($33.52^{\circ}N$) to 352 DU for Unggi ($42.32^{\circ}N$) in almost zonally symmetric pattern over the Korean Peninsula, with the latitudinal gradient of 6 DU $degree^{-1}$. It is apparent that seasonal variability of total ozone increases from Jeju toward Unggi. The annual mean total ozone for Seoul shows 323 DU, with the maximum of 359 DU in March and the minimum of 291 DU in October. It is found that the day to day variability in total ozone exhibits annual mean of 5.7% in increase and -5.2% in decrease. The variability as large as 38.4% in increase and 30.3% in decrease has been observed, respectively. The long-term trend analysis (e.g., WMO, 1999) of monthly total ozone data (1985~2009) merged by satellite and ground-based measurements over the Korean Peninsula shows increase of 1.27% $decade^{-1}$ to 0.80% $decade^{-1}$ from Jeju to Unggi, respectively, showing systematic decrease of the trend magnitude with latitude. This study also presents a new analysis of ozone density and trends in the vertical distribution of ozone for Seoul with data up to the end of 2009. The mean vertical distributions of ozone show that the maximum value of the ozone density is 16.5 DU $km^{-1}$ in the middle stratospheric layer between 24 km and 28 km. About 90.0% and 71.5% of total ozone are found in the troposphere and in the stratosphere between 15 and 33 km, respectively. The trend analysis reconfirms the previous results of significant positive ozone trend, of up to 5% $decade^{-1}$, in the troposphere and the lower stratosphere (0~24 km), with negative trend, of up to -5% $decade^{-1}$, in the stratosphere (24~38 km). In addition, the Umkehr data show a positive trend of about 3% $decade^{-1}$ in the upper stratosphere (38~48 km).

• Journal of the Korean earth science society
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• v.23 no.6
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• pp.494-506
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• 2002

The Korean Standard-Time (KST) in practice is about 30 minutes earlier than Korea’s solar-time. Suitability of tile KST is analysed by whether it is suitable for the society in general and for the mental and physical health of the Korean people. About 56% of the countries in the world use single standard-time coincident, 18% are 30 minutes earlier, and 21% are an hour or more earlier than their solar-times, respectively, and only 5% have standard-times 30 minutes later than their solar-time. This means adoption of the standard-time earlier than the solar-time is rather acceptable in most countries without any harm to the mental and physical health of their people. Because Korea is located on the western margin of the I-time zone (which is used standard longitude of 135$^{\circ}$E and is used as KST), KST is about 30 minutes earlier than Korea’s solar-time. This situation does not seem to affect adversely the physical, physiological or psychological activities of the people of Korea. It also helps in effective use of the daily time schedule throughout the year, moreover it diminishes the necessity of the summer-time system in the Korea. If H$^{\ast}$-time of the longitude of 127.5$^{\circ}$E that passes through middle of the Korean peninsular is used as KST, non-integer time difference from UTC is inevitable which may be of great inconvenience, and also the introduction of a summer-time system like most countries in high latitude, using their standard-time coincidentally with or even earlier than their solar time, will become essential.

• Korean Journal of Plant Resources
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• v.18 no.1
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• pp.85-116
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• 2005

Gyeryongsan(845m) is located at $36^{\circ}\;18'\;02'\;-36^{\circ}\;23'\;38'$ in latitude, at $127^{\circ}\;11'\;60'-127^{\circ}\;17'\;86'$ in longitude and on Nonsan City and Gongju City in Chungnam Province. Gyeryongsan shows the typical vegetation patterns including the middle area of temperate region represented by the secondary forests of Quercus mongotica and Q. serrata. And we tried to discuss on the distribution and availability of vascular plants including economical plants. The results of plant collection and their investigation from April in 1998 to October in 2002 are as follows : The vascular plants consist of total 684 taxa; 3 hybrids, 12 forms, 84 varieties, 1 subspecies, 584 species, 357 genera, 100 families, 34 orders, 4 classes, 3 subphyla. In this area useful resources plants were 277 taxa$(40.5\%)$ forage source, 261 taxa$(38.2\%)$ edible source, 204 taxa$(29.8\%)$ medicinal source, 80 taxa$(11.7\%)$ ornamental source, 20 taxa$(2.9\%)$ timber source, 3 taxa$(0.4\%)$ industrial raw material source respectively. Also, the Korean endemic plants are 29 taxa($4.2\%$ among total 684 taxa); 5 varieties, 24 species, 27 genera, 20 families. And rare and endangered plants are 2 taxa; Paeonia obovate, Gastrodia elata. Also, the naturalized plants are 31 taxa($4.5\%$ among total 684 taxa and $13.7\%$ among the total naturalized plants in Korea).